Oscillatory patterns in sympathetic neural discharge and cardiovascular variables during orthostatic stimulus

NASA Technical Reports Server (NTRS)

Furlan, R.; Porta, A.; Costa, F.; Tank, J.; Baker, L.; Schiavi, R.; Robertson, D.; Malliani, A.; Mosqueda-Garcia, R.

2000-01-01

BACKGROUND: We tested the hypothesis that a common oscillatory pattern might characterize the rhythmic discharge of muscle sympathetic nerve activity (MSNA) and the spontaneous variability of heart rate and systolic arterial pressure (SAP) during a physiological increase of sympathetic activity induced by the head-up tilt maneuver. METHODS AND RESULTS: Ten healthy subjects underwent continuous recordings of ECG, intra-arterial pressure, respiratory activity, central venous pressure, and MSNA, both in the recumbent position and during 75 degrees head-up tilt. Venous samplings for catecholamine assessment were obtained at rest and during the fifth minute of tilt. Spectrum and cross-spectrum analyses of R-R interval, SAP, and MSNA variabilities and of respiratory activity provided the low (LF, 0.1 Hz) and high frequency (HF, 0.27 Hz) rhythmic components of each signal and assessed their linear relationships. Compared with the recumbent position, tilt reduced central venous pressure, but blood pressure was unchanged. Heart rate, MSNA, and plasma epinephrine and norepinephrine levels increased, suggesting a marked enhancement of overall sympathetic activity. During tilt, LF(MSNA) increased compared with the level in the supine position; this mirrored similar changes observed in the LF components of R-R interval and SAP variabilities. The increase of LF(MSNA) was proportional to the amount of the sympathetic discharge. The coupling between LF components of MSNA and R-R interval and SAP variabilities was enhanced during tilt compared with rest. CONCLUSIONS: During the sympathetic activation induced by tilt, a similar oscillatory pattern based on an increased LF rhythmicity characterized the spontaneous variability of neural sympathetic discharge, R-R interval, and arterial pressure.

Physiological basis for human autonomic rhythms

NASA Technical Reports Server (NTRS)

Eckberg, D. L.

2000-01-01

Oscillations of arterial pressures, heart periods, and muscle sympathetic nerve activity have been studied intensively in recent years to explore otherwise obscure human neurophysiological mechanisms. The best-studied rhythms are those occurring at breathing frequencies. Published evidence indicates that respiratory fluctuations of muscle sympathetic nerve activity and electrocardiographic R-R intervals result primarily from the action of a central 'gate' that opens during expiration and closes during inspiration. Parallel respiratory fluctuations of arterial pressures and R-R intervals are thought to be secondary to arterial baroreflex physiology: changes in systolic pressure provoke changes in the R-R interval. However, growing evidence suggests that these parallel oscillations result from the influence of respiration on sympathetic and vagal-cardiac motoneurones rather than from baroreflex physiology. There is a rapidly growing literature on the use of mathematical models of low- and high-frequency (respiratory) R-R interval fluctuations in characterizing instantaneous 'sympathovagal balance'. The case for this approach is based primarily on measurements made with patients in upright tilt. However, the strong linear relation between such measures as the ratio of low- to high-frequency R-R interval oscillations and the angle of the tilt reflects exclusively the reductions of the vagal (high-frequency) component. As the sympathetic component does not change in tilt, the low- to high-frequency R-R interval ratio provides no proof that sympathetic activity increases. Moreover, the validity of extrapolating from measurements performed during upright tilt to measurements during supine rest has not been established. Nonetheless, it is clear that measures of heart rate variability provide important prognostic information in patients with cardiovascular diseases. It is not known whether reduced heart rate variability is merely a marker for the severity of disease or a measurement that identifies functional reflex abnormalities contributing to terminal dysrhythmias.

Inverse correlation between the standard deviation of R-R intervals in supine position and the simplified menopausal index in women with climacteric symptoms.

PubMed

Yanagihara, Nobuyuki; Seki, Meikan; Nakano, Masahiro; Hachisuga, Toru; Goto, Yukio

2014-06-01

Disturbance of autonomic nervous activity has been thought to play a role in the climacteric symptoms of postmenopausal women. This study was therefore designed to investigate the relationship between autonomic nervous activity and climacteric symptoms in postmenopausal Japanese women. The autonomic nervous activity of 40 Japanese women with climacteric symptoms and 40 Japanese women without climacteric symptoms was measured by power spectral analysis of heart rate variability using a standard hexagonal radar chart. The scores for climacteric symptoms were determined using the simplified menopausal index. Sympathetic excitability and irritability, as well as the standard deviation of mean R-R intervals in supine position, were significantly (P < 0.01, 0.05, and 0.001, respectively) decreased in women with climacteric symptoms. There was a negative correlation between the standard deviation of mean R-R intervals in supine position and the simplified menopausal index score. The lack of control for potential confounding variables was a limitation of this study. In climacteric women, the standard deviation of mean R-R intervals in supine position is negatively correlated with the simplified menopausal index score.

SCD-HeFT: Use of RR Interval Statistics for Long-term Risk Stratification for Arrhythmic Sudden Cardiac Death

PubMed Central

Au-yeung, Wan-tai M.; Reinhall, Per; Poole, Jeanne E.; Anderson, Jill; Johnson, George; Fletcher, Ross D.; Moore, Hans J.; Mark, Daniel B.; Lee, Kerry L.; Bardy, Gust H.

2015-01-01

Background In the SCD-HeFT a significant fraction of the congestive heart failure (CHF) patients ultimately did not die suddenly from arrhythmic causes. CHF patients will benefit from better tools to identify if ICD therapy is needed. Objective To identify predictor variables from baseline SCD-HeFT patients’ RR intervals that correlate to arrhythmic sudden cardiac death (SCD) and mortality and to design an ICD therapy screening test. Methods Ten predictor variables were extracted from pre-randomization Holter data from 475 patients enrolled in the SCD-HeFT ICD arm using novel and traditional heart rate variability methods. All variables were correlated to SCD using Mann Whitney-Wilcoxon test and receiver operating characteristic analysis. ICD therapy screening tests were designed by minimizing the cost of false classifications. Survival analysis, including log-rank test and Cox models, was also performed. Results α1 and α2 from detrended fluctuation analysis, the ratio of low to high frequency power, the number of PVCs per hour and heart rate turbulence slope are all statistically significant for predicting the occurrences of SCD (p<0.001) and survival (log-rank p<0.01). The most powerful multivariate predictor tool using the Cox Proportional Hazards was α2 with a hazard ratio of 0.0465 (95% CI: 0.00528 – 0.409, p<0.01). Conclusion Predictor variables from RR intervals correlate to the occurrences of SCD and distinguish survival among SCD-HeFT ICD patients. We believe SCD prediction models should incorporate Holter based RR interval analysis to refine ICD patient selection especially in removing patients who are unlikely to benefit from ICD therapy. PMID:26096609

Validation of Heart Rate Monitor Polar RS800 for Heart Rate Variability Analysis During Exercise.

PubMed

Hernando, David; Garatachea, Nuria; Almeida, Rute; Casajús, Jose A; Bailón, Raquel

2018-03-01

Hernando, D, Garatachea, N, Almeida, R, Casajús, JA, and Bailón, R. Validation of heart rate monitor Polar RS800 for heart rate variability analysis during exercise. J Strength Cond Res 32(3): 716-725, 2018-Heart rate variability (HRV) analysis during exercise is an interesting noninvasive tool to measure the cardiovascular response to the stress of exercise. Wearable heart rate monitors are a comfortable option to measure interbeat (RR) intervals while doing physical activities. It is necessary to evaluate the agreement between HRV parameters derived from the RR series recorded by wearable devices and those derived from an electrocardiogram (ECG) during dynamic exercise of low to high intensity. Twenty-three male volunteers performed an exercise stress test on a cycle ergometer. Subjects wore a Polar RS800 device, whereas ECG was also recorded simultaneously to extract the reference RR intervals. A time-frequency spectral analysis was performed to extract the instantaneous mean heart rate (HRM), and the power of low-frequency (PLF) and high-frequency (PHF) components, the latter centered on the respiratory frequency. Analysis was done in intervals of different exercise intensity based on oxygen consumption. Linear correlation, reliability, and agreement were computed in each interval. The agreement between the RR series obtained from the Polar device and from the ECG is high throughout the whole test although the shorter the RR is, the more differences there are. Both methods are interchangeable when analyzing HRV at rest. At high exercise intensity, HRM and PLF still presented a high correlation (ρ > 0.8) and excellent reliability and agreement indices (above 0.9). However, the PHF measurements from the Polar showed reliability and agreement coefficients around 0.5 or lower when the level of the exercise increases (for levels of O2 above 60%).

Assessment of cardiac autonomic regulation and ventricular repolarization after off-pump coronary artery bypass grafting.

PubMed

Kalisnik, Jurij M; Avbelj, Viktor; Trobec, Roman; Ivaskovic, Daroslav; Vidmar, Gaj; Troise, Giovanni; Gersak, Borut

2006-01-01

Altered autonomic regulation precipitates cardiac arrhythmias and increases the risk of sudden cardiac death. This risk is further increased by changes in ventricular repolarization. Autonomic regulation is deranged in patients after myocardial on-pump revascularization. We aimed to clarify how off-pump coronary artery bypass grafting (CABG) affects postoperative cardiac autonomic regulation and ventricular repolarization within 4 weeks after CABG. Forty-two patients (mean age, 61.9 +/- 9.3 years; mean EURO score 2.6 +/- 1.9) were electively admitted for off-pump CABG. The electrocardiographic and respiratory waveform recordings were performed in the afternoon in the supine position for 10 minutes. Autonomic modulation was assessed using heart rate variability analysis. Power spectra were computed from 5-minute stable RR intervals using Fourier Transform analysis. Total power of spectra was defined in the range of 0.01 to 0.40 Hz, high-frequency power within 0.15 to 0.40 Hz, and low-frequency power within 0.04 to 0.15 Hz. Normalized power was defined as a ratio of power in each band/total power. The high- and low-frequency power as well as their normalized values indicated cardiac vagal and sympathetic modulation, respectively. Ventricular repolarization was assessed using QT interval, QT interval variability, and QT-RR interdependence analysis. QT intervals were determined from the beginning of the 5-minute segments. QT interval variability was evaluated by a T-wave template-matching algorithm. Pearson correlation between length of RR and QT interval was applied to study QT-RR characteristics. The results were tested for significance using the Fisher exact test, nonpaired t test, and analysis of variance; a P <.05 was considered significant. The frequency of arrhythmic events and heart rate increased from the fourth to the seventh postoperative day and returned to preoperative levels 4 weeks after CABG. Heart rate variability measures indicating autonomic modulation remained depressed even 4 weeks after the procedure. QT variability index increased from -1.2 +/- 0.5 to -0.8 +/- 0.4 on the fourth day after the operation (P <.05) and returned to -1.0 +/- 0.5 4 weeks after CABG (P = not significant). QT-RR correlation decreased from 0.41 to 0.23 (P <.05) and remained significantly impaired as long as 4 weeks after CABG. Observed faster heart rates until 1 week after off-pump CABG imply excessive adrenergic activation, which is comparable to on-pump CABG procedure rates. The results indicate profound autonomic derangement and loss of rate-dependent regulation after off-pump CABG even 4 weeks after operation. Restituted repolarization as assessed by QT variability index 4 weeks postoperatively corresponded with decreased frequency of rhythm disturbances 4 weeks after CABG. The loss of coupling between QT and RR intervals shows increased electrical instability postoperatively, which may serve as an additional promoter for postoperative arrhythmias, especially at higher heart rates.

Heart-Rate Variability During Deep Sleep in World-Class Alpine Skiers: A Time-Efficient Alternative to Morning Supine Measurements.

PubMed

Herzig, David; Testorelli, Moreno; Olstad, Daniela Schäfer; Erlacher, Daniel; Achermann, Peter; Eser, Prisca; Wilhelm, Matthias

2017-05-01

It is increasingly popular to use heart-rate variability (HRV) to tailor training for athletes. A time-efficient method is HRV assessment during deep sleep. To validate the selection of deep-sleep segments identified by RR intervals with simultaneous electroencephalography (EEG) recordings and to compare HRV parameters of these segments with those of standard morning supine measurements. In 11 world-class alpine skiers, RR intervals were monitored during 10 nights, and simultaneous EEGs were recorded during 2-4 nights. Deep sleep was determined from the HRV signal and verified by delta power from the EEG recordings. Four further segments were chosen for HRV determination, namely, a 4-h segment from midnight to 4 AM and three 5-min segments: 1 just before awakening, 1 after waking in supine position, and 1 in standing after orthostatic challenge. Training load was recorded every day. A total of 80 night and 68 morning measurements of 9 athletes were analyzed. Good correspondence between the phases selected by RR intervals vs those selected by EEG was found. Concerning root-mean-squared difference of successive RR intervals (RMSSD), a marker for parasympathetic activity, the best relationship with the morning supine measurement was found in deep sleep. HRV is a simple tool for approximating deep-sleep phases, and HRV measurement during deep sleep could provide a time-efficient alternative to HRV in supine position.

Effects of controlled breathing, mental activity and mental stress with or without verbalization on heart rate variability.

PubMed

Bernardi, L; Wdowczyk-Szulc, J; Valenti, C; Castoldi, S; Passino, C; Spadacini, G; Sleight, P

2000-05-01

To assess whether talking or reading (silently or aloud) could affect heart rate variability (HRV) and to what extent these changes require a simultaneous recording of respiratory activity to be correctly interpreted. Sympathetic predominance in the power spectrum obtained from short- and long-term HRV recordings predicts a poor prognosis in a number of cardiac diseases. Heart rate variability is often recorded without measuring respiration; slow breaths might artefactually increase low frequency power in RR interval (RR) and falsely mimic sympathetic activation. In 12 healthy volunteers we evaluated the effect of free talking and reading, silently and aloud, on respiration, RR and blood pressure (BP). We also compared spontaneous breathing to controlled breathing and mental arithmetic, silent or aloud. The power in the so called low- (LF) and high-frequency (HF) bands in RR and BP was obtained from autoregressive power spectrum analysis. Compared with spontaneous breathing, reading silently increased the speed of breathing (p < 0.05), decreased mean RR and RR variability and increased BP. Reading aloud, free talking and mental arithmetic aloud shifted the respiratory frequency into the LF band, thus increasing LF% and decreasing HF% to a similar degree in both RR and respiration, with decrease in mean RR but with minor differences in crude RR variability. Simple mental and verbal activities markedly affect HRV through changes in respiratory frequency. This possibility should be taken into account when analyzing HRV without simultaneous acquisition and analysis of respiration.

Radiation dose to patients and image quality evaluation from coronary 256-slice computed tomographic angiography

NASA Astrophysics Data System (ADS)

Chen, Liang-Kuang; Wu, Tung-Hsin; Yang, Ching-Ching; Tsai, Chia-Jung; Lee, Jason J. S.

2010-07-01

The aim of this study is to assess radiation dose and the corresponding image quality from suggested CT protocols which depends on different mean heart rate and high heart rate variability by using 256-slice CT. Fifty consecutive patients referred for a cardiac CT examination were included in this study. All coronary computed tomographic angiography (CCTA) examinations were performed on a 256-slice CT scanner with one of five different protocols: retrospective ECG-gating (RGH) with full dose exposure in all R-R intervals (protocol A), RGH of 30-80% pulsing window with tube current modulation (B), RGH of 78±5% pulsing window with tube current modulation (C), prospective ECG-triggering (PGT) of 78% R-R interval with 5% padding window (D) and PGT of 78% R-R interval without padding window (E). Radiation dose parameters and image quality scoring were determined and compared. In this study, no significant differences were found in comparison on image quality of the five different protocols. Protocol A obtained the highest radiation dose comparing with those of protocols B, C, D and E by a factor of 1.6, 2.4, 2.5 and 4.3, respectively ( p<0.001), which were ranged between 2.7 and 11.8 mSv. The PGT could significantly reduce radiation dose delivered to patients, as compared to the RGH. However, the use of PGT has limitations and is only good in assessing cases with lower mean heart rate and stable heart rate variability. With higher mean heart rate and high heart rate variability circumstances, the RGH within 30-80% of R-R interval pulsing window is suggested as a feasible technique for assessing diagnostic performance.

The use of heart rate variability in assessing precompetitive stress in high-standard judo athletes.

PubMed

Morales, J; Garcia, V; García-Massó, X; Salvá, P; Escobar, R; Buscà, B

2013-02-01

The objective of this study is to examine the sensitivity to and changes in heart rate variability (HRV) in stressful situations before judo competitions and to observe the differences among judo athletes according to their competitive standards in both official and unofficial competitions. 24 (10 male and 14 female) national- and international-standard athletes were evaluated. Each participant answered the Revised Competitive State Anxiety Inventory (CSAI-2R) and their HRV was recorded both during an official and unofficial competition. The MANOVA showed significant main effects of the athlete's standard and the type of competition in CSAI-2R, in HRV time domain, in HRV frequency domain and in HRV nonlinear analysis (p<0.05). International-standard judo athletes have lower somatic anxiety, cognitive anxiety, heart rate and low-high frequency ratio than national-standard athletes (p<0.05). International-standard athletes have a higher confidence, mean RR interval, standard deviation of RR, square root of the mean squared difference of successive RR intervals, number of consecutive RR that differ by more than 5 ms, short-term variability, long-term variability, long-range scaling exponents and short-range scaling exponent than national-standard judo athletes. In conclusion, international-standard athletes show less pre-competitive anxiety than the national-standard athletes and HRV analysis is sensitive to changes in pre-competitive anxiety. © Georg Thieme Verlag KG Stuttgart · New York.

[Evaluation of autonomic nervous system function with heart rate variability analysis in patients with hyperthyroidism and during euthyroidism after pharmacologic and surgical treatment].

PubMed

Barczyński, M; Tabor, S; Thor, P

1997-01-01

The aim of the present study was both to estimate autonomic nervous system (ANS) function in patients with hyperthyroidism by the heart rate variability (HRV) analysis and to evaluate the impact of pharmacological and surgical treatment on the ANS function. Analysis of the HRV underwent 10 female patients in course of thyreotoxicosis and after reaching full clinical and biochemical euthyroidism, after pharmacological therapy and in month after surgical treatment. The 10 minutes records at rest, in horizontal position were evaluated. The HRV parameters like mean of the heart rate, mean of RR intervals, standard deviation of all normal RR intervals (SDNN), range of the heart rate variability, low frequency (LF), high frequency (HF) components of the heart rate power spectral density and LF/HF ratio were assessed. The results were compared to those obtained from 10 age-, sex-, and body mass index-matched control subjects. The statistical significance (p < 0.05) was found in reduction of range of RR intervals, in increase of LF/HF ratio and in decrease of SDNN in hyperthyroidism in comparison to the control group (151.6/346.8 ms; 2.4/0.74; 24.4/57.2 ms2). In course of pharmacological euthyroidism there were statistically significant (p < 0.05) increase of range of RR intervals, reduction of LF/HF ratio and increase of SDNN in comparison to hyperthyroidism (270/151.6 ms; 0.995/2.4; 39/24.4 ms2). In euthyroidism after surgical treatment all the above parameters kept the similar levels as in pharmacological euthyroidism (no statistical significance for p < 0.05). On the base of the outcomes it was considered that in hyperthyroid patients there is advantage of sympathetic part of ANS over parasympathetic one which is due to sharp reduction of parasympathetic system activity. Pharmacological therapy with thyreostatics normalises balance of ANS to the level of the control group and after surgical treatment the balance keeps the same. Moreover, in the estimation of ANS as important as LF/HF ratio is the mean range of RR intervals.

Causal transfer function analysis to describe closed loop interactions between cardiovascular and cardiorespiratory variability signals.

PubMed

Faes, L; Porta, A; Cucino, R; Cerutti, S; Antolini, R; Nollo, G

2004-06-01

Although the concept of transfer function is intrinsically related to an input-output relationship, the traditional and widely used estimation method merges both feedback and feedforward interactions between the two analyzed signals. This limitation may endanger the reliability of transfer function analysis in biological systems characterized by closed loop interactions. In this study, a method for estimating the transfer function between closed loop interacting signals was proposed and validated in the field of cardiovascular and cardiorespiratory variability. The two analyzed signals x and y were described by a bivariate autoregressive model, and the causal transfer function from x to y was estimated after imposing causality by setting to zero the model coefficients representative of the reverse effects from y to x. The method was tested in simulations reproducing linear open and closed loop interactions, showing a better adherence of the causal transfer function to the theoretical curves with respect to the traditional approach in presence of non-negligible reverse effects. It was then applied in ten healthy young subjects to characterize the transfer functions from respiration to heart period (RR interval) and to systolic arterial pressure (SAP), and from SAP to RR interval. In the first two cases, the causal and non-causal transfer function estimates were comparable, indicating that respiration, acting as exogenous signal, sets an open loop relationship upon SAP and RR interval. On the contrary, causal and traditional transfer functions from SAP to RR were significantly different, suggesting the presence of a considerable influence on the opposite causal direction. Thus, the proposed causal approach seems to be appropriate for the estimation of parameters, like the gain and the phase lag from SAP to RR interval, which have a large clinical and physiological relevance.

Improved detection of congestive heart failure via probabilistic symbolic pattern recognition and heart rate variability metrics.

PubMed

Mahajan, Ruhi; Viangteeravat, Teeradache; Akbilgic, Oguz

2017-12-01

A timely diagnosis of congestive heart failure (CHF) is crucial to evade a life-threatening event. This paper presents a novel probabilistic symbol pattern recognition (PSPR) approach to detect CHF in subjects from their cardiac interbeat (R-R) intervals. PSPR discretizes each continuous R-R interval time series by mapping them onto an eight-symbol alphabet and then models the pattern transition behavior in the symbolic representation of the series. The PSPR-based analysis of the discretized series from 107 subjects (69 normal and 38 CHF subjects) yielded discernible features to distinguish normal subjects and subjects with CHF. In addition to PSPR features, we also extracted features using the time-domain heart rate variability measures such as average and standard deviation of R-R intervals. An ensemble of bagged decision trees was used to classify two groups resulting in a five-fold cross-validation accuracy, specificity, and sensitivity of 98.1%, 100%, and 94.7%, respectively. However, a 20% holdout validation yielded an accuracy, specificity, and sensitivity of 99.5%, 100%, and 98.57%, respectively. Results from this study suggest that features obtained with the combination of PSPR and long-term heart rate variability measures can be used in developing automated CHF diagnosis tools. Copyright © 2017 Elsevier B.V. All rights reserved.

Reliability of Heart Rate Variability in Children: Influence of Sex and Body Position During Data Collection.

PubMed

Silva, Carla Cristiane; Bertollo, Maurizio; Reichert, Felipe Fossati; Boullosa, Daniel Alexandre; Nakamura, Fábio Yuzo

2017-05-01

To examine which body position and indices present better reliability of heart rate variability (HRV) measures in children and to compare the HRV analyzed in different body positions between sexes. Twenty eutrophic prepubertal children of each sex participated in the study. The RR intervals were recorded using a portable heart rate monitor twice a day for 7 min in the supine, sitting, and standing positions. The reproducibility was analyzed using the intraclass correlation coefficient (ICC; two way mixed) and within-subject coefficient of variation (CV).Two-way ANOVA with repeated measures was used to compare the sexes. High levels of reproducibility were indicated by higher ICC in the root-mean-square difference of successive normal RR intervals (RMSSD: 0.93 and 0.94) and Poincaré plot of the short-term RR interval variability (SD1: 0.92 and 0.94) parameters for boys and girls, respectively, in the supine position. The ICCs were lower in the sitting and standing positions for all HRV indices. In addition, the girls presented significantly higher values than the boys for SDNN and absolute high frequency (HF; p < .05) in the supine position. The supine position is the most reproducible for the HRV indices in both sexes, especially the vagal related indices.

Monty Roberts' Public Demonstrations: Preliminary Report on the Heart Rate and Heart Rate Variability of Horses Undergoing Training during Live Audience Events.

PubMed

Loftus, Loni; Marks, Kelly; Jones-McVey, Rosie; Gonzales, Jose L; Fowler, Veronica L

2016-09-09

Effective training of horses relies on the trainer's awareness of learning theory and equine ethology, and should be undertaken with skill and time. Some trainers, such as Monty Roberts, share their methods through the medium of public demonstrations. This paper describes the opportunistic analysis of beat-to-beat (RR) intervals and heart rate variability (HRV) of ten horses being used in Monty Roberts' public demonstrations within the United Kingdom. RR and HRV was measured in the stable before training and during training. The HRV variables standard deviation of the RR interval (SDRR), root mean square of successive RR differences (RMSSD), geometric means standard deviation 1 (SD1) and 2 (SD2), along with the low and high frequency ratio (LF/HF ratio) were calculated. The minimum, average and maximum RR intervals were significantly lower in training (indicative of an increase in heart rate as measured in beats-per-minute) than in the stable ( p = 0.0006; p = 0.01; p = 0.03). SDRR, RMSSD, SD1, SD2 and the LF/HF ratio were all significantly lower in training than in the stable ( p = 0.001; p = 0.049; p = 0.049; p = 0.001; p = 0.01). When comparing the HR and HRV of horses during Join-up (®) to overall training, there were no significant differences in any variable with the exception of maximum RR which was significantly lower ( p = 0.007) during Join-up (®) , indicative of short increases in physical exertion (canter) associated with this training exercise. In conclusion, training of horses during public demonstrations is a low-moderate physiological, rather than psychological stressor for horses. The physiological stress responses observed within this study were comparable or less to those previously reported in the literature for horses being trained outside of public audience events. Furthermore, there is no evidence that the use of Join-up (®) alters HR and HRV in a way to suggest that this training method negatively affects the psychological welfare of horses.

Validity of the Polar V800 monitor for measuring heart rate variability in mountain running route conditions.

PubMed

Caminal, Pere; Sola, Fuensanta; Gomis, Pedro; Guasch, Eduard; Perera, Alexandre; Soriano, Núria; Mont, Lluis

2018-03-01

This study was conducted to test, in mountain running route conditions, the accuracy of the Polar V800™ monitor as a suitable device for monitoring the heart rate variability (HRV) of runners. Eighteen healthy subjects ran a route that included a range of running slopes such as those encountered in trail and ultra-trail races. The comparative study of a V800 and a Holter SEER 12 ECG Recorder™ included the analysis of RR time series and short-term HRV analysis. A correction algorithm was designed to obtain the corrected Polar RR intervals. Six 5-min segments related to different running slopes were considered for each subject. The correlation between corrected V800 RR intervals and Holter RR intervals was very high (r = 0.99, p < 0.001), and the bias was less than 1 ms. The limits of agreement (LoA) obtained for SDNN and RMSSD were (- 0.25 to 0.32 ms) and (- 0.90 to 1.08 ms), respectively. The effect size (ES) obtained in the time domain HRV parameters was considered small (ES < 0.2). Frequency domain HRV parameters did not differ (p > 0.05) and were well correlated (r ≥ 0.96, p < 0.001). Narrow limits of agreement, high correlations and small effect size suggest that the Polar V800 is a valid tool for the analysis of heart rate variability in athletes while running high endurance events such as marathon, trail, and ultra-trail races.

A novel device based on smart textile to control heart's activity during exercise.

PubMed

Romagnoli, Marco; Alis, Rafael; Guillen, Javier; Basterra, Javier; Villacastin, J P; Guillen, Sergio

2014-06-01

In recent years, several systems have been developed to control cardiac function during exercise, and some are also capable of recording RR data to provide heart rate variability (HRV) analyses. In this study we compare time between heart beats and HRV parameters obtained with a smart textile system (GOW; Weartech sl., Spain) and an electrocardiogram machine commonly used in hospitals during continuous cycling tests. Twelve cardiology patients performed a 30-min cycling test at stable submaximal intensity. RR interval data were recorded during the test by both systems. 3-min RR segments were taken to compare the time intervals between beats and HRV variables using Bland-Altman analyses and intraclass correlation coefficients. Limits of agreement (LoAs) on RR intervals were stable at around 3 ms (widest LoAs -5.754 to 6.094 ms, tightest LoAs -2.557 to 3.105 ms, medium LoAs -3.638 ± 0.812 to 3.145 ± 0.539 ms). HRV parameters related to short-term change presented wide LoAs (RMSSD -0.17 to 18.41 %, HF -17.64 to 33.21 %, SD1 -0.50 to 17.54 %) as an effect of the error measurement of the GOW system. The GOW system is a valid tool for controlling HR during physical activity, although its use as a clinical tool for HRV cannot be supported.

How to Calculate Renyi Entropy from Heart Rate Variability, and Why it Matters for Detecting Cardiac Autonomic Neuropathy.

PubMed

Cornforth, David J; Tarvainen, Mika P; Jelinek, Herbert F

2014-01-01

Cardiac autonomic neuropathy (CAN) is a disease that involves nerve damage leading to an abnormal control of heart rate. An open question is to what extent this condition is detectable from heart rate variability (HRV), which provides information only on successive intervals between heart beats, yet is non-invasive and easy to obtain from a three-lead ECG recording. A variety of measures may be extracted from HRV, including time domain, frequency domain, and more complex non-linear measures. Among the latter, Renyi entropy has been proposed as a suitable measure that can be used to discriminate CAN from controls. However, all entropy methods require estimation of probabilities, and there are a number of ways in which this estimation can be made. In this work, we calculate Renyi entropy using several variations of the histogram method and a density method based on sequences of RR intervals. In all, we calculate Renyi entropy using nine methods and compare their effectiveness in separating the different classes of participants. We found that the histogram method using single RR intervals yields an entropy measure that is either incapable of discriminating CAN from controls, or that it provides little information that could not be gained from the SD of the RR intervals. In contrast, probabilities calculated using a density method based on sequences of RR intervals yield an entropy measure that provides good separation between groups of participants and provides information not available from the SD. The main contribution of this work is that different approaches to calculating probability may affect the success of detecting disease. Our results bring new clarity to the methods used to calculate the Renyi entropy in general, and in particular, to the successful detection of CAN.

How to Calculate Renyi Entropy from Heart Rate Variability, and Why it Matters for Detecting Cardiac Autonomic Neuropathy

PubMed Central

Cornforth, David J.;  Tarvainen, Mika P.; Jelinek, Herbert F.

2014-01-01

Cardiac autonomic neuropathy (CAN) is a disease that involves nerve damage leading to an abnormal control of heart rate. An open question is to what extent this condition is detectable from heart rate variability (HRV), which provides information only on successive intervals between heart beats, yet is non-invasive and easy to obtain from a three-lead ECG recording. A variety of measures may be extracted from HRV, including time domain, frequency domain, and more complex non-linear measures. Among the latter, Renyi entropy has been proposed as a suitable measure that can be used to discriminate CAN from controls. However, all entropy methods require estimation of probabilities, and there are a number of ways in which this estimation can be made. In this work, we calculate Renyi entropy using several variations of the histogram method and a density method based on sequences of RR intervals. In all, we calculate Renyi entropy using nine methods and compare their effectiveness in separating the different classes of participants. We found that the histogram method using single RR intervals yields an entropy measure that is either incapable of discriminating CAN from controls, or that it provides little information that could not be gained from the SD of the RR intervals. In contrast, probabilities calculated using a density method based on sequences of RR intervals yield an entropy measure that provides good separation between groups of participants and provides information not available from the SD. The main contribution of this work is that different approaches to calculating probability may affect the success of detecting disease. Our results bring new clarity to the methods used to calculate the Renyi entropy in general, and in particular, to the successful detection of CAN. PMID:25250311

The Impact of Computing Interpregnancy Intervals Without Accounting for Intervening Pregnancy Events.

PubMed

Conzuelo-Rodriguez, Gabriel; Naimi, Ashley I

2018-03-01

Short interpregnancy intervals (IPI) are associated with poor birth outcomes. Often, only livebirths are considered to estimate IPI. The objective of our work is to explore whether the associations between demographic, behavioural, and pregnancy variables and IPI change when events other than livebirth are included. We used data from the 2006-10 and 2011-13 period of the National Survey of Family Growth (NSFG). We defined IPI using the conception date of the index pregnancy and the event date of the previous one ending in (i) livebirth; (ii) stillbirth; (iii) miscarriage; (iv) abortion; or (v) any of these events. Risk ratios (RR) were estimated for short IPI (<18 months), and demographic, pregnancy, and behavioural variables using log-linear models. When intervening events are included, the association between short IPI and its predictors vary by definition, especially for unintended versus intended pregnancies (only livebirth risk ratio [RR] 1.34, 95% confidence interval [CI] 1.2, 1.5) versus livebirth and miscarriage RR 1.14, 95% CI 1.0, 1.3) and women older than 30 vs. younger than 20 at resolution of the previous pregnancy (only livebirth RR 1.22, 95% CI 1.0, 1.5 versus livebirth and miscarriage RR 1.36, 95% CI 1.2, 1.6). Including miscarriage as an intervening event in the calculation of IPI changes the association between several risk factors and short IPI. However, the association between short IPI and preterm birth does not vary when different IPI calculations are used. © 2018 John Wiley & Sons Ltd.

Correlation between indexes of autonomic maneuvers and heart rate variability in hemodialysis patients.

PubMed

Vieira, Carlos Felipe Delmondes; Lima, Márcia Maria Oliveira; Costa, Henrique Silveira; Diniz, Karen Marina Alves; Guião, João Paulo Lemos; Alves, Frederico Lopes; Maciel, Emílio Henrique; Brandao, Vanessa Gomes; Figueiredo, Pedro Henrique Scheidt

2016-06-01

The autonomic maneuvers are simple methods to evaluate autonomic balance, but the association between autonomic maneuvers and heart rate variability (HRV) in hemodialysis patients remains unknown. This study aimed to evaluate the correlation between HRV and respiratory sinus arrhythmia (RSA) and Valsalva maneuver (VM) indexes in hemodialysis patients and to compare two methods for RSA indexes acquisitions. Forty-eight volunteers on hemodialysis (66.7 % men) were evaluated by VM, RSA, and 24 h Holter monitoring. At the VM, the Valsalva index (VI) was the variable considered. In the RSA, the ratio and difference between the RR intervals of inspiratory and expiratory phase (E:I and E-I, respectively) were considered by traditional form (average of respiratory cycles) and independent respiratory cycles (E:Iindep and E-Iindep). The HRV indexes evaluated were standard deviation of all normal RR intervals (SDNN), standard deviation of sequential 5-min RR interval means (SDANN), root mean square of the successive differences (rMSSD) and percentage of adjacent RR intervals with difference of duration greater than 50 ms (pNN50). The SDNN, SDANN showed significant correlation with all classic indexes of RSA (E:I: r = 0.62, 0.55, respectively, E-I: r = 0.64, 0.57, respectively), E:Iindep (r = 0.59, 0.54, respectively), E-Iindep (r = 0.47, 0.43, respectively) and VI (r = 0.42, 0.34, respectively). Significant correlation of rMSSD with E:I (r = 0.37), E-I (r = 0.41) and E:Iindep (r = 0.34) was also observed. There was no association of any variable with pNN50. Have been show high values for all variables of independent cycles method (p < 0.05). The autonomic maneuvers, especially RSA, are useful methods to evaluate cardiac autonomic function in hemodialysis patients. The acquisition of the RSA index by independent cycles should not be used in this population.

Climatic, high tide and vector variables and the transmission of Ross River virus.

PubMed

Tong, S; Hu, W; Nicholls, N; Dale, P; MacKenzie, J S; Patz, J; McMichael, A J

2005-11-01

This report assesses the impact of the variability in environmental and vector factors on the transmission of Ross River virus (RRV) in Brisbane, Australia. Poisson time series regression analyses were conducted using monthly data on the counts of RRV cases, climate variables (Southern Oscillation Index and rainfall), high tides and mosquito density for the period of 1998-2001. The results indicate that increases in the high tide (relative risk (RR): 1.65; 95% confidence interval (CI): 1.20-2.26), rainfall (RR: 1.45; 95% CI: 1.21-1.73), mosquito density (RR: 1.17; 95% CI: 1.09-1.27), the density of Culex annulirostris (RR: 1.25; 95% CI: 1.13-1.37) and the density of Ochlerotatus vigilax (RR: 2.39; 95% CI: 2.30-2.48), each at a lag of 1 month, were statistically significantly associated with the rise of monthly RRV incidence. The results of the present study might facilitate the development of early warning systems for reducing the incidence of this wide-spread disease in Australia and other Pacific island nations.

Autonomic nervous functions in fetal type Minamata disease patients: assessment of heart rate variability.

PubMed

Oka, Tomoko; Matsukura, Makoto; Okamoto, Miwako; Harada, Noriaki; Kitano, Takao; Miike, Teruhisa; Futatsuka, Makoto

2002-12-01

In order to assess the cardiovascular autonomic nervous functions in patients with fetal type Minamata disease (FMD), we investigated blood pressure (BP), and conducted time and frequency domain analysis of heart rate variability (HRV). Subjects were 9 patients in Meisuien recognized as FMD, and 13 healthy age matched control subjects. HRV and BP were assessed after subjects rested in a supine position for 10 minutes. Electrocardiographic (ECG) data were collected for 3 minutes during natural breathing. Time domain analysis (the average of R-R intervals [Mean RR], standard deviation of R-R intervals [SD RR], coefficient of variation [CV]), and frequency domain analysis by fast Fourier transformation (FFT) (power of low frequency [LF] and high frequency [HF] component, expressed in normalized units[nu]) were then conducted. In the time domain analysis, the mean RR of the FMD group was significantly lower than that of the control group. Neither SD RR nor CV showed significant differences between the two groups, but both tended to be lower in the FMD group. In the frequency domain analysis, the HF component of the FMD group was significantly lower than that of the control group. Pulse pressure (PP) was significantly lower in the FMD subjects. These findings suggest that parasympathetic nervous dysfunction might exist in FMD patients, who were exposed to high doses of methylmercury (MeHg) during the prenatal period. Decrease of PP might be due to degenerative changes of blood vessels driven by exposure to high doses of MeHg.

Changes in cortisol release and heart rate variability in sport horses during long-distance road transport.

PubMed

Schmidt, A; Biau, S; Möstl, E; Becker-Birck, M; Morillon, B; Aurich, J; Faure, J-M; Aurich, C

2010-04-01

It is widely accepted that transport is stressful for horses, but only a few studies are available involving horses that are transported regularly and are accustomed to transport. We determined salivary cortisol immunoreactivity (IR), fecal cortisol metabolites, beat-to-beat (RR) interval, and heart rate variability (HRV) in transport-experienced horses (N=7) in response to a 2-d outbound road transport over 1370 km and 2-d return transport 8 d later. Salivary cortisol IR was low until 60 min before transport but had increased (P<0.05) 30 min before loading. Transport caused a further marked increase (P<0.001), but the response tended to decrease with each day of transport. Concentrations of fecal cortisol metabolites increased on the second day of both outbound and return transports and reached a maximum the following day (P<0.001). During the first 90 min on Day 1 of outbound transport, mean RR interval decreased (P<0.001). Standard deviations of RR interval (SDRR) decreased transiently (P<0.01). The root mean square of successive RR differences (RMSSD) decreased at the beginning of the outbound and return transports (P<0.01), reflecting reduced parasympathetic tone. On the first day of both outbound and return transports, a transient rise in geometric HRV variable standard deviation 2 (SD2) occurred (P<0.01), indicating increased sympathetic activity. In conclusion, transport of experienced horses leads to increased cortisol release and changes in heart rate and HRV, which is indicative of stress. The degree of these changes tended to be most pronounced on the first day of both outbound and return transport. Copyright 2009 Elsevier Inc. All rights reserved.

A pilot investigation of the effect of extremely low frequency pulsed electromagnetic fields on humans' heart rate variability.

PubMed

Baldi, Emilio; Baldi, Claudio; Lithgow, Brian J

2007-01-01

The question whether pulsed electromagnetic field (PEMF) can affect the heart rhythm is still controversial. This study investigates the effects on the cardiocirculatory system of ELF-PEMFs. It is a follow-up to an investigation made of the possible therapeutic effect ELF-PEMFs, using a commercially available magneto therapeutic unit, had on soft tissue injury repair in humans. Modulation of heart rate (HR) or heart rate variability (HRV) can be detected from changes in periodicity of the R-R interval and/or from changes in the numbers of heart-beat/min (bpm), however, R-R interval analysis gives only a quantitative insight into HRV. A qualitative understanding of HRV can be obtained considering the power spectral density (PSD) of the R-R intervals Fourier transform. In this study PSD is the investigative tool used, more specifically the low frequency (LF) PSD and high frequency (HF) PSD ratio (LF/HF) which is an indicator of sympatho-vagal balance. To obtain the PSD value, variations of the R-R time intervals were evaluated from a continuously recorded ECG. The results show a HR variation in all the subjects when they are exposed to the same ELF-PEMF. This variation can be detected by observing the change in the sympatho-vagal equilibrium, which is an indicator of modulation of heart activity. Variation of the LF/HF PSD ratio mainly occurs at transition times from exposure to nonexposure, or vice versa. Also of interest are the results obtained during the exposure of one subject to a range of different ELF-PEMFs. This pilot study suggests that a full investigation into the effect of ELF-PEMFs on the cardiovascular system is justified.

Human instrumental performance in ratio and interval contingencies: A challenge for associative theory.

PubMed

Pérez, Omar D; Aitken, Michael R F; Zhukovsky, Peter; Soto, Fabián A; Urcelay, Gonzalo P; Dickinson, Anthony

2016-12-15

Associative learning theories regard the probability of reinforcement as the critical factor determining responding. However, the role of this factor in instrumental conditioning is not completely clear. In fact, free-operant experiments show that participants respond at a higher rate on variable ratio than on variable interval schedules even though the reinforcement probability is matched between the schedules. This difference has been attributed to the differential reinforcement of long inter-response times (IRTs) by interval schedules, which acts to slow responding. In the present study, we used a novel experimental design to investigate human responding under random ratio (RR) and regulated probability interval (RPI) schedules, a type of interval schedule that sets a reinforcement probability independently of the IRT duration. Participants responded on each type of schedule before a final choice test in which they distributed responding between two schedules similar to those experienced during training. Although response rates did not differ during training, the participants responded at a lower rate on the RPI schedule than on the matched RR schedule during the choice test. This preference cannot be attributed to a higher probability of reinforcement for long IRTs and questions the idea that similar associative processes underlie classical and instrumental conditioning.

Health system determinants of infant, child and maternal mortality: A cross-sectional study of UN member countries

PubMed Central

2011-01-01

Objective Few studies have examined the link between health system strength and important public health outcomes across nations. We examined the association between health system indicators and mortality rates. Methods We used mixed effects linear regression models to investigate the strength of association between outcome and explanatory variables, while accounting for geographic clustering of countries. We modelled infant mortality rate (IMR), child mortality rate (CMR), and maternal mortality rate (MMR) using 13 explanatory variables as outlined by the World Health Organization. Results Significant protective health system determinants related to IMR included higher physician density (adjusted rate ratio [aRR] 0.81; 95% Confidence Interval [CI] 0.71-0.91), higher sustainable access to water and sanitation (aRR 0.85; 95% CI 0.78-0.93), and having a less corrupt government (aRR 0.57; 95% CI 0.40-0.80). Out-of-pocket expenditures on health (aRR 1.29; 95% CI 1.03-1.62) were a risk factor. The same four variables were significantly related to CMR after controlling for other variables. Protective determinants of MMR included access to water and sanitation (aRR 0.88; 95% CI 0.82-0.94), having a less corrupt government (aRR 0.49; 95%; CI 0.36-0.66), and higher total expenditures on health per capita (aRR 0.84; 95% CI 0.77-0.92). Higher fertility rates (aRR 2.85; 95% CI: 2.02-4.00) were found to be a significant risk factor for MMR. Conclusion Several key measures of a health system predict mortality in infants, children, and maternal mortality rates at the national level. Improving access to water and sanitation and reducing corruption within the health sector should become priorities. PMID:22023970

High Resolution ECG for Evaluation of QT Interval Variability during Exposure to Acute Hypoxia

NASA Technical Reports Server (NTRS)

Zupet, P.; Finderle, Z.; Schlegel, Todd T.; Starc, V.

2010-01-01

Ventricular repolarization instability as quantified by the index of QT interval variability (QTVI) is one of the best predictors for risk of malignant ventricular arrhythmias and sudden cardiac death. Because it is difficult to appropriately monitor early signs of organ dysfunction at high altitude, we investigated whether high resolution advanced ECG (HR-ECG) analysis might be helpful as a non-invasive and easy-to-use tool for evaluating the risk of cardiac arrhythmias during exposure to acute hypoxia. 19 non-acclimatized healthy trained alpinists (age 37, 8 plus or minus 4,7 years) participated in the study. Five-minute high-resolution 12-lead electrocardiograms (ECGs) were recorded (Cardiosoft) in each subject at rest in the supine position breathing room air and then after breathing 12.5% oxygen for 30 min. For beat-to-beat RR and QT variability, the program of Starc was utilized to derive standard time domain measures such as root mean square of the successive interval difference (rMSSD) of RRV and QTV, the corrected QT interval (QTc) and the QTVI in lead II. Changes were evaluated with paired-samples t-test with p-values less than 0.05 considered statistically significant. As expected, the RR interval and its variability both decreased with increasing altitude, with p = 0.000 and p = 0.005, respectively. Significant increases were found in both the rMSSDQT and the QTVI in lead II, with p = 0.002 and p = 0.003, respectively. There was no change in QTc interval length (p = non significant). QT variability parameters may be useful for evaluating changes in ventricular repolarization caused by hypoxia. These changes might be driven by increases in sympathetic nervous system activity at ventricular level.

Effect of repeated exercise and recovery on heart rate variability in elite trotting horses during high intensity interval training.

PubMed

Cottin, F; Barrey, E; Lopes, P; Billat, V

2006-08-01

Interval training is a commonly used training method for trotting horses. In addition, trainers are provided with efficient and inexpensive heart rate monitor devices for the management of training. Since the high frequency (HF) frequency peak (fHF) of heart rate variability (HRV) corresponds to the breathing frequency in combination with stride frequency during trotting, it is hypothesised that modifications of breathing and stride frequencies induced by repeated exercise could be detected from fHF. RR interval time series of 7 trotting horses were recorded during an interval training session. Interval training was made up of 5 successive 800 m high-velocity trotting runs (H1, H2...H5) separated by 1 min recovery bouts at low speed (R1, R2...R5). Fast Fourier transform (FFT) and Poincaré plot analysis techniques were applied to RR series. Repeated exercise had significant effects on HRV components during interval training. Despite constant trotting velocities during high-speed and recovery, repetition induced a decrease in mean RR interval (H1: 295 +/- 19 vs. H5: 283 +/- 15 msec, P<0.05) and in the root mean square of successive differences in RR series (RMSSD; H1: 6.31 +/- 1.28 vs. H5: 5.31 +/- 1.31 msec, P<0.05). Furthermore, high-speed and recovery repetitions induced an increase in fHF (H1: 1.37 +/- 0.35 vs. H5: 1.62 +/- 0.40 Hz and R1: 0.22 +/- 0.02 vs. R4: 0.64 +/- 0.38 Hz, P<0.05). Hence, recovery induced a decrease in the s.d. of the successive RR series (SDRR; R3: 10.5 +/- 3.96 vs. R5: 6.17 +/- 2.65 msecs, P>0.05) and in the long term index of Poincaré plot (SD2; R1: 43.29 +/- 28.90 vs. R5: 18.19 +/- 9.35 msecs, P<0.05). The observed increase in fHF during the interval training could be induced by alterations of the coupling between breathing and stride frequency linked to the emergence of fatigue. The decrease in SD2 and SDRR during successive recovery bouts could be linked with a deterioration of the recovery pattern. HRV can provide breathing frequency data of Standardbreds during training without any respiratory device. Furthermore, HRV could provide useful makers of the emergence of fatigue states during training.

Heart rate dynamics in patients with stable angina pectoris and utility of fractal and complexity measures

NASA Technical Reports Server (NTRS)

Makikallio, T. H.; Ristimae, T.; Airaksinen, K. E.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

1998-01-01

Dynamic analysis techniques may uncover abnormalities in heart rate (HR) behavior that are not easily detectable with conventional statistical measures. However, the applicability of these new methods for detecting possible abnormalities in HR behavior in various cardiovascular disorders is not well established. Conventional measures of HR variability were compared with short-term (< or = 11 beats, alpha1) and long-term (> 11 beats, alpha2) fractal correlation properties and with approximate entropy of RR interval data in 38 patients with stable angina pectoris without previous myocardial infarction or cardiac medication at the time of the study and 38 age-matched healthy controls. The short- and long-term fractal scaling exponents (alpha1, alpha2) were significantly higher in the coronary patients than in the healthy controls (1.34 +/- 0.15 vs 1.11 +/- 0.12 [p <0.001] and 1.10 +/- 0.08 vs 1.04 +/- 0.06 [p <0.01], respectively), and they also had lower approximate entropy (p <0.05), standard deviation of all RR intervals (p <0.01), and high-frequency spectral component of HR variability (p <0.05). The short-term fractal scaling exponent performed better than other heart rate variability parameters in differentiating patients with coronary artery disease from healthy subjects, but it was not related to the clinical or angiographic severity of coronary artery disease or any single nonspectral or spectral measure of HR variability in this retrospective study. Patients with stable angina pectoris have altered fractal properties and reduced complexity in their RR interval dynamics relative to age-matched healthy subjects. Dynamic analysis may complement traditional analyses in detecting altered HR behavior in patients with stable angina pectoris.

RR-Interval variance of electrocardiogram for atrial fibrillation detection

NASA Astrophysics Data System (ADS)

Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

2016-11-01

Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

Reading Ability as an Estimator of Premorbid Intelligence: Does It Remain Stable Among Ethnically Diverse HIV+ Adults?

PubMed Central

Olsen, J. Pat; Fellows, Robert P.; Rivera-Mindt, Monica; Morgello, Susan; Byrd, Desiree A.

2015-01-01

The Wide Range Achievement Test, 3rd edition, Reading-Recognition subtest (WRAT-3 RR) is an established measure of premorbid ability. Furthermore, its long-term reliability is not well documented, particularly in diverse populations with CNS-relevant disease. Objective: We examined test-retest reliability of the WRAT-3 RR over time in an HIV+ sample of predominantly racial/ethnic minority adults. Method: Participants (N = 88) completed a comprehensive neuropsychological battery, including the WRAT-3 RR, on at least two separate study visits. Intraclass correlation coefficients (ICCs) were computed using scores from baseline and follow-up assessments to determine the test-retest reliability of the WRAT-3 RR across racial/ethnic groups and changes in medical (immunological) and clinical (neurocognitive) factors. Additionally, Fisher’s Z tests were used to determine the significance of the differences between ICCs. Results: The average test-retest interval was 58.7 months (SD=36.4). The overall WRAT-3 RR test-retest reliability was high (r = .97, p < .001), and remained robust across all demographic, medical, and clinical variables (all r’s > .92). Intraclass correlation coefficients did not differ significantly between the subgroups tested (all Fisher’s Z p’s > .05). Conclusions: Overall, this study supports the appropriateness of word-reading tests, such as the WRAT-3 RR, for use as stable premorbid IQ estimates among ethnically diverse groups. Moreover, this study supports the reliability of this measure in the context of change in health and neurocognitive status, and in lengthy inter-test intervals. These findings offer strong rationale for reading as a “hold” test, even in the presence of a chronic, variable disease such as HIV. PMID:26689235

Complexity of the heart rhythm after heart transplantation by entropy of transition network for RR-increments of RR time intervals between heartbeats.

PubMed

Makowiec, Danuta; Struzik, Zbigniew; Graff, Beata; Wdowczyk-Szulc, Joanna; Zarczynska-Buchnowiecka, Marta; Gruchala, Marcin; Rynkiewicz, Andrzej

2013-01-01

Network models have been used to capture, represent and analyse characteristics of living organisms and general properties of complex systems. The use of network representations in the characterization of time series complexity is a relatively new but quickly developing branch of time series analysis. In particular, beat-to-beat heart rate variability can be mapped out in a network of RR-increments, which is a directed and weighted graph with vertices representing RR-increments and the edges of which correspond to subsequent increments. We evaluate entropy measures selected from these network representations in records of healthy subjects and heart transplant patients, and provide an interpretation of the results.

Sudden Death After Febrile Seizure Case Report: Cerebral Suppression Precedes Severe Bradycardia.

PubMed

Myers, Kenneth A; McPherson, Robyn E; Clegg, Robin; Buchhalter, Jeffrey

2017-11-01

A 20-month-old girl with a complex chromosomal disorder had first presentation of febrile status epilepticus and was admitted to the hospital. Two days after her initial seizure, she died suddenly and unexpectedly during a video EEG monitoring study. An advanced analysis of the physiologic changes in the hours and minutes leading up to death was undertaken. The electrocardiography over the last 19 minutes of life was reviewed, and the R-R intervals were manually measured. Heart rate variability was assessed through calculation of the SD of the R-R intervals and the root mean square of successive differences over successive 100 beat periods. Instantaneous heart rate, SD of the R-R intervals, the root mean square of successive differences, and oxygen saturation were plotted against time over the last 19 minutes of life. Diffuse cerebral suppression on EEG was observed 10 minutes before death, followed minutes later by severe bradycardia and increased heart rate variability. Although the child did not meet criteria for a diagnosis of epilepsy, the sequence of physiologic changes leading up to death suggests a pathophysiology similar to sudden unexplained death in epilepsy. A comparable pattern of diffuse cerebral suppression preceding parasympathetic overactivity has been suggested in some rare cases of adults who have experienced sudden unexplained death in epilepsy during video EEG monitoring. Copyright © 2017 by the American Academy of Pediatrics.

Mutual information detects a decreased interdependence between RR and SAP in orthostatic intolerance after microgravity condition.

PubMed

Raimondi, G; Chillemi, S; Michelassi, C; Di Garbo, A; Varanini, M; Legramante, J; Balocchi, R

2002-07-01

Orthostatic intolerance is the most serious symptom of cardiovascular deconditioning induced by microgravity. However, the exact mechanisms underlying these alterations have not been completely clarified. Several methods for studying the time series of systolic arterial pressure and RR interval have been proposed both in the time and in the frequency domain. However, these methods did not produce definitive results. In fact heart rate and arterial pressure show a complex pattern of global variability which is likely due to non linear feedback which involves the autonomic nervous system and to "stochastic" influences. Aim of this study was to evaluate the degree of interdependence between the mechanisms responsible for the variability of SAP and RR signals in subjects exposed to head down (HD). This quantification was achieved by using Mutual Information (MI).

Assessment of cardiac autonomic functions by heart rate recovery, heart rate variability and QT dynamicity parameters in patients with acromegaly.

PubMed

Dural, Muhammet; Kabakcı, Giray; Cınar, Neşe; Erbaş, Tomris; Canpolat, Uğur; Gürses, Kadri Murat; Tokgözoğlu, Lale; Oto, Ali; Kaya, Ergün Barış; Yorgun, Hikmet; Sahiner, Levent; Dağdelen, Selçuk; Aytemir, Kudret

2014-04-01

Cardiovascular complications are the most common causes of morbidity and mortality in acromegaly. However, there is little data regarding cardiac autonomic functions in these patients. Herein, we aimed to investigate several parameters of cardiac autonomic functions in patients with acromegaly compared to healthy subjects. We enrolled 20 newly diagnosed acromegalic patients (55% female, age:45.7 ± 12.6 years) and 32 age- and gender-matched healthy subjects. All participants underwent 24 h Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting 1st, 2nd and 3rd minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV) and QT dynamicity analysis. Baseline characteristics were similar except diabetes mellitus and hypertension among groups. Mean HRR1 (29.2 ± 12.3 vs 42.6 ± 6.5, p = 0.001), HRR2 (43.5 ± 15.6 vs 61.1 ± 10.8, p = 0.001) and HRR3 (46.4 ± 16.2 vs 65.8 ± 9.8, p = 0.001) values were significantly higher in control group. HRV parameters as, SDNN [standard deviation of all NN intervals] (p = 0.001), SDANN [SD of the 5 min mean RR intervals] (p = 0.001), RMSSD [root square of successive differences in RR interval] (p = 0.001), PNN50 [proportion of differences in successive NN intervals >50 ms] (p = 0.001) and high-frequency [HF] (p = 0.001) were significantly decreased in patients with acromegaly; but low frequency [LF] (p = 0.046) and LF/HF (p = 0.001) were significantly higher in acromegaly patients. QTec (p = 0.009), QTac/RR slope (p = 0.017) and QTec/RR slope (p = 0.01) were significantly higher in patients with acromegaly. Additionally, there were significant negative correlation of disease duration with HRR2, HRR3, SDNN, PNN50, RMSSD, variability index. Our study results suggest that cardiac autonomic functions are impaired in patients with acromegaly. Further large scale studies are needed to exhibit the prognostic significance of impaired autonomic functions in patients with acromegaly.

Activation of N-methyl-d-aspartate receptors reduces heart rate variability and facilitates atrial fibrillation in rats.

PubMed

Shi, Shaobo; Liu, Tao; Wang, Dandan; Zhang, Yan; Liang, Jinjun; Yang, Bo; Hu, Dan

2017-07-01

The goal of this study was to assess the effects of N-methyl-d-aspartate (NMDA) receptors activation on heart rate variability (HRV) and susceptibility to atrial fibrillation (AF). Rats were randomized for treatment with saline, NMDA (agonist of NMDA receptors), or NMDA plus MK-801 (antagonist of NMDA receptors) for 2 weeks. Heart rate variability was evaluated by using implantable electrocardiogram telemeters. Atrial fibrillation susceptibility was assessed with programmed stimulation in isolated hearts. Compared with the controls, the NMDA-treated rats displayed a decrease in the standard deviation of normal RR intervals, the standard deviation of the average RR intervals, the mean of the 5-min standard deviations of RR intervals, the root mean square of successive differences, and high frequency (HF); and an increase in low frequency (LF) and LF/HF (all P< 0.01). Additionally, the NMDA-treated rats showed prolonged activation latency and reduced effective refractory period (all P< 0.01). Importantly, AF was induced in all NMDA-treated rats. While atrial fibrosis developed, connexin40 downgraded and metalloproteinase 9 upgraded in the NMDA-treated rats (all P< 0.01). Most of the above alterations were mitigated by co-administering with MK-801. These results indicate that NMDA receptors activation reduces HRV and enhances AF inducibility, with cardiac autonomic imbalance, atrial fibrosis, and degradation of gap junction protein identified as potential mechanistic contributors. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

R-R interval variations influence the degree of mitral regurgitation in dogs with myxomatous mitral valve disease.

PubMed

Reimann, M J; Møller, J E; Häggström, J; Markussen, B; Holen, A E W; Falk, T; Olsen, L H

2014-03-01

Mitral regurgitation (MR) due to myxomatous mitral valve disease (MMVD) is a frequent finding in Cavalier King Charles Spaniels (CKCSs). Sinus arrhythmia and atrial premature complexes leading to R-R interval variations occur in dogs. The aim of the study was to evaluate whether the duration of the R-R interval immediately influences the degree of MR assessed by echocardiography in dogs. Clinical examination including echocardiography was performed in 103 privately-owned dogs: 16 control Beagles, 70 CKCSs with different degree of MR and 17 dogs of different breeds with clinical signs of congestive heart failure due to MMVD. The severity of MR was evaluated in apical four-chamber view using colour Doppler flow mapping (maximum % of the left atrium area) and colour Doppler M-mode (duration in ms). The influence of the ratio between present and preceding R-R interval on MR severity was evaluated in 10 consecutive R-R intervals using a linear mixed model for repeated measurements. MR severity was increased when a short R-R interval was followed by a long R-R interval in CKCSs with different degrees of MR (P<0.005 when adjusted for multiple testing). The relationship was not significant in control dogs with minimal MR and in dogs with severe MR and clinical signs of heart failure. In conclusion, MR severity increases in long R-R intervals when these follow a short R-R interval in CKCSs with different degrees of MR due to asymptomatic MMVD. Thus, R-R interval variations may affect the echocardiographic grading of MR in CKCSs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of moderate and heavy endurance exercise on nocturnal HRV.

PubMed

Hynynen, E; Vesterinen, V; Rusko, H; Nummela, A

2010-06-01

This study examined the effects of endurance exercise on nocturnal autonomic modulation. Nocturnal R-R intervals were collected after a rest day, after a moderate endurance exercise and after a marathon run in ten healthy, physically active men. Heart rate variability (HRV) was analyzed as a continuous four-hour period starting 30 min after going to bed for sleep. In relation to average nocturnal heart rate after rest day, increases to 109+/-6% and 130+/-11% of baseline were found after moderate endurance exercise and marathon, respectively. Standard deviation of R-R intervals decreased to 90+/-9% and 64+/-10%, root-mean-square of differences between adjacent R-R intervals to 87+/-10% and 55+/-16%, and high frequency power to 77+/-19% and 34+/-19% of baseline after moderate endurance exercise and marathon, respectively. Also nocturnal low frequency power decreased to 56+/-26% of baseline after the marathon. Changes in nocturnal heart rate and HRV suggest prolonged dose-response effects on autonomic modulation after exercises, which may give useful information on the extent of exercise-induced nocturnal autonomic modulation and disturbance to the homeostasis.

Autonomic adaptation after traditional and reverse swimming training periodizations.

PubMed

Clemente-Suárez, Vicente Javier; Fernandes, R J; Arroyo-Toledo, J J; Figueiredo, P; González-Ravé, J M; Vilas-Boas, J P

2015-03-01

The objective of the present study was to analyze the autonomic response of trained swimmers to traditional and reverse training periodization models. Seventeen swimmers were divided in two groups, performing a traditional periodization (TPG) or a reverse periodization (RPG) during a period of 10 weeks. Heart rate variability and 50 m swimming performance were analyzed before and after the training programs. After training, the TPG decreased the values of the high frequency band (HF), the number of differences between adjacent normal R-R intervals longer than 50 ms (NN50) and the percentage of differences between adjacent normal R-R intervals more than 50 ms (pNN50), and the RPG increased the values of HF and square root of the mean of the sum of the squared differences between adjacent normal R-R intervals (RMSSD). None of the groups improved significantly their performance in the 50-m test. The autonomic response of swimmers was different depending on the periodization performed, with the reverse periodization model leading to higher autonomic adaption. Complementary, the data suggests that autonomic adaptations were not critical for the 50-m swimming performance.

Influence of aging and chronic heart failure on temporal dispersion of myocardial repolarization

PubMed Central

Piccirillo, Gianfranco; Moscucci, Federica; Pascucci, Matteo; Pappadà, Maria Antonella; D’Alessandro, Gaetana; Rossi, Pietro; Quaglione, Raffaele; Di Barba, Daniele; Barillà, Francesco; Magrì, Damiano

2013-01-01

Background and purpose: QT and Tpeak-Tend (Te) intervals are associated with sudden cardiac death in patients with chronic heart failure (CHF). We studied age-dependent influence on short-term temporal dispersion of these two variables in patients with postischemic CHF. Method: We grouped 75 CHF and 53 healthy control subjects into three age subsets: ≤50 years, >50 years and ≤65 years, and >65 years. We then calculated the following indices: QT and Te variability index (QTVI and TeVI), the ratio between the short-term variability (STV) of QT or Te, and the STV of resting rate (RR) (QT/RR STV and Te/RR STV). Results: In all different age subgroups, patients with CHF showed a higher level of QTVI than age-matched control subjects (≤50 years: P < 0.0001; >50 years and ≤65 years: P < 0.05; >65 years: P < 0.05). Patients with CHF < 50 years old also had all repolarization variability indices higher than normal age-matched controls (TeVI, P < 0.05; QT/RR STV, P < 0.05; Te/RR STV, P < 0.05), whereas we did not find any difference between the two older classes of subjects. Both QTVI (r2: 0.178, P < 0.05) and TeVI (r2: 0.433, P < 0.001) were positively related to age in normal subjects, even if the first correlation was weaker than the second one. Conclusion: Our data showed that QTVI could be used in all ages to evaluate repolarization temporal liability, whereas the other indices are deeply influenced by age. Probably, the age-dependent increase in QTVI was more influenced by a reduction of RR variability reported in older normal subjects. PMID:23662051

Influence of aging and chronic heart failure on temporal dispersion of myocardial repolarization.

PubMed

Piccirillo, Gianfranco; Moscucci, Federica; Pascucci, Matteo; Pappadà, Maria Antonella; D'Alessandro, Gaetana; Rossi, Pietro; Quaglione, Raffaele; Di Barba, Daniele; Barillà, Francesco; Magrì, Damiano

2013-01-01

QT and T(peak)-T(end) (Te) intervals are associated with sudden cardiac death in patients with chronic heart failure (CHF). We studied age-dependent influence on short-term temporal dispersion of these two variables in patients with postischemic CHF. We grouped 75 CHF and 53 healthy control subjects into three age subsets: ≤ 50 years, >50 years and ≤ 65 years, and >65 years. We then calculated the following indices: QT and Te variability index (QTVI and TeVI), the ratio between the short-term variability (STV) of QT or Te, and the STV of resting rate (RR) (QT/RR STV and Te/RR STV). In all different age subgroups, patients with CHF showed a higher level of QTVI than age-matched control subjects (≤ 50 years: P < 0.0001; >50 years and ≤ 65 years: P < 0.05; >65 years: P < 0.05). Patients with CHF < 50 years old also had all repolarization variability indices higher than normal age-matched controls (TeVI, P < 0.05; QT/RR STV, P < 0.05; Te/RR STV, P < 0.05), whereas we did not find any difference between the two older classes of subjects. Both QTVI (r²: 0.178, P < 0.05) and TeVI (r²: 0.433, P < 0.001) were positively related to age in normal subjects, even if the first correlation was weaker than the second one. Our data showed that QTVI could be used in all ages to evaluate repolarization temporal liability, whereas the other indices are deeply influenced by age. Probably, the age-dependent increase in QTVI was more influenced by a reduction of RR variability reported in older normal subjects.

Autonomic cardiovascular modulation with three different anesthetic strategies during neurosurgical procedures.

PubMed

Guzzetti, S; Bassani, T; Latini, R; Masson, S; Barlera, S; Citerio, G; Porta, A

2015-01-01

Autonomic cardiovascular modulation during surgery might be affected by different anesthetic strategies. Aim of the present study was to assess autonomic control during three different anesthetic strategies in the course of neurosurgical procedures by the linear and non-linear analysis of two cardiovascular signals. Heart rate (EKG-RR intervals) and systolic arterial pressure (SAP) signals were analyzed in 93 patients during elective neurosurgical procedures at fixed points: anesthetic induction, dura mater opening, first and second hour of surgery, dura mater and skin closure. Patients were randomly assigned to three anesthetic strategies: sevoflurane+fentanyl (S-F), sevoflurane+remifentanil (S-R) and propofol+remifentanil (P-R). All the three anesthetic strategies were characterized by a reduction of RR and SAP variability. A more active autonomic sympathetic modulation, as ratio of low to high frequency spectral components of RR variability (LF/HF), was present in the P-R group vs. S-R group. This is confirmed by non-linear symbolic analysis of RR series and SAP variability analysis. In addition, an increased parasympathetic modulation was suggested by symbolic analysis of RR series during the second hour of surgery in S-F group. Despite an important reduction of cardiovascular signal variability, the analysis of RR and SAP signals were capable to detect information about autonomic control during anesthesia. Symbolic analysis (non-linear) seems to be able to highlight the differences of both the sympathetic (slow) and vagal (fast) modulation among anesthetics, while spectral analysis (linear) underlines the same differences but only in terms of balance between the two neural control systems.

Important influence of respiration on human R-R interval power spectra is largely ignored

NASA Technical Reports Server (NTRS)

Brown, T. E.; Beightol, L. A.; Koh, J.; Eckberg, D. L.

1993-01-01

Frequency-domain analyses of R-R intervals are used widely to estimate levels of autonomic neural traffic to the human heart. Because respiration modulates autonomic activity, we determined for nine healthy subjects the influence of breathing frequency and tidal volume on R-R interval power spectra (fast-Fourier transform method). We also surveyed published literature to determine current practices in this burgeoning field of scientific inquiry. Supine subjects breathed at rates of 6, 7.5, 10, 15, 17.1, 20, and 24 breaths/min and with nominal tidal volumes of 1,000 and 1,500 ml. R-R interval power at respiratory and low (0.06-0.14 Hz) frequencies declined significantly as breathing frequency increased. R-R interval power at respiratory frequencies was significantly greater at a tidal volume of 1,500 than 1,000 ml. Neither breathing frequency nor tidal volume influenced average R-R intervals significantly. Our review of studies reporting human R-R interval power spectra showed that 51% of the studies controlled respiratory rate, 11% controlled tidal volume, and 11% controlled both respiratory rate and tidal volume. The major implications of our analyses are that breathing parameters strongly influence low-frequency as well as respiratory frequency R-R interval power spectra and that this influence is largely ignored in published research.

The effects of cold water immersion with different dosages (duration and temperature variations) on heart rate variability post-exercise recovery: A randomized controlled trial.

PubMed

Almeida, Aline C; Machado, Aryane F; Albuquerque, Maíra C; Netto, Lara M; Vanderlei, Franciele M; Vanderlei, Luiz Carlos M; Junior, Jayme Netto; Pastre, Carlos M

2016-08-01

The aim of the present study was to investigate the effects of cold water immersion during post-exercise recovery, with different durations and temperatures, on heart rate variability indices. Hundred participants performed a protocol of jumps and a Wingate test, and immediately afterwards were immersed in cold water, according to the characteristics of each group (CG: control; G1: 5' at 9±1°C; G2: 5' at 14±1°C; G3: 15' at 9±1°C; G4: 15' at 14±1°C). Analyses were performed at baseline, during the CWI recuperative technique (TRec) and 20, 30, 40, 50 and 60min post-exercise. The average HRV indices of all RR-intervals in each analysis period (MeanRR), standard deviation of normal RR-intervals (SDNN), square root of the mean of the sum of the squares of differences between adjacent RR-intervals (RMSSD), spectral components of very low frequency (VLF), low frequency (LF) and high frequency (HF), scatter of points perpendicular to the line of identity of the Poincaré Plot (SD1) and scatter points along the line of identity (SD2) were assessed. Mean RR, VLF and LF presented an anticipated return to baseline values at all the intervention groups, but the same was observed for SDNN and SD2 only in the immersion for 15min at 14°C group (G4). In addition, G4 presented higher values when compared to CG. These findings demonstrate that if the purpose of the recovery process is restoration of cardiac autonomic modulation, the technique is recommended, specifically for 15min at 14°C. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Recurrence Plots: a New Tool for Quantification of Cardiac Autonomic Nervous System Recovery after Transplant.

PubMed

Takakura, Isabela Thomaz; Hoshi, Rosangela Akemi; Santos, Márcio Antonio; Pivatelli, Flávio Correa; Nóbrega, João Honorato; Guedes, Débora Linhares; Nogueira, Victor Freire; Frota, Tuane Queiroz; Castelo, Gabriel Castro; Godoy, Moacir Fernandes de

2017-01-01

To evaluate a possible evolutionary post-heart transplant return of autonomic function using quantitative and qualitative information from recurrence plots. Using electrocardiography, 102 RR tachograms of 45 patients (64.4% male) who underwent heart transplantation and that were available in the database were analyzed at different follow-up periods. The RR tachograms were collected from patients in the supine position for about 20 minutes. A time series with 1000 RR intervals was analyzed, a recurrence plot was created, and the following quantitative variables were evaluated: percentage of determinism, percentage of recurrence, average diagonal length, Shannon entropy, and sample entropy, as well as the visual qualitative aspect. Quantitative and qualitative signs of heart rate variability recovery were observed after transplantation. There is evidence that autonomic innervation of the heart begins to happen gradually after transplantation. Quantitative and qualitative analyses of recurrence can be useful tools for monitoring cardiac transplant patients and detecting the gradual return of heart rate variability.

Using complexity metrics with R-R intervals and BPM heart rate measures.

PubMed

Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian; Jegindø, Else-Marie

2013-01-01

Lately, growing attention in the health sciences has been paid to the dynamics of heart rate as indicator of impending failures and for prognoses. Likewise, in social and cognitive sciences, heart rate is increasingly employed as a measure of arousal, emotional engagement and as a marker of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically on variability of the data, different choices regarding the kind of measures can have a substantial impact on the results. In this article we compare linear and non-linear statistics on two prominent types of heart beat data, beat-to-beat intervals (R-R interval) and beats-per-min (BPM). As a proof-of-concept, we employ a simple rest-exercise-rest task and show that non-linear statistics-fractal (DFA) and recurrence (RQA) analyses-reveal information about heart beat activity above and beyond the simple level of heart rate. Non-linear statistics unveil sustained post-exercise effects on heart rate dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to non-linear analyses, the success of non-linear methods for BPM data critically depends on their construction. Generally, "oversampled" BPM time-series can be recommended as they retain most of the information about non-linear aspects of heart beat dynamics.

Using complexity metrics with R-R intervals and BPM heart rate measures

PubMed Central

Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian; Jegindø, Else-Marie

2013-01-01

Lately, growing attention in the health sciences has been paid to the dynamics of heart rate as indicator of impending failures and for prognoses. Likewise, in social and cognitive sciences, heart rate is increasingly employed as a measure of arousal, emotional engagement and as a marker of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically on variability of the data, different choices regarding the kind of measures can have a substantial impact on the results. In this article we compare linear and non-linear statistics on two prominent types of heart beat data, beat-to-beat intervals (R-R interval) and beats-per-min (BPM). As a proof-of-concept, we employ a simple rest-exercise-rest task and show that non-linear statistics—fractal (DFA) and recurrence (RQA) analyses—reveal information about heart beat activity above and beyond the simple level of heart rate. Non-linear statistics unveil sustained post-exercise effects on heart rate dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to non-linear analyses, the success of non-linear methods for BPM data critically depends on their construction. Generally, “oversampled” BPM time-series can be recommended as they retain most of the information about non-linear aspects of heart beat dynamics. PMID:23964244

Auditory stimulation with music influences the geometric indices of heart rate variability in response to the postural change maneuver.

PubMed

de Castro, Bianca C R; Guida, Heraldo L; Roque, Adriano L; de Abreu, Luiz Carlos; Ferreira, Celso; Marcomini, Renata S; Monteiro, Carlos B M; Adami, Fernando; Ribeiro, Viviane F; Fonseca, Fernando L A; Santos, Vilma N S; Valenti, Vitor E

2014-01-01

It is poor in the literature the behavior of the geometric indices of heart rate variability (HRV) during the musical auditory stimulation. The objective is to investigate the acute effects of classic musical auditory stimulation on the geometric indexes of HRV in women in response to the postural change maneuver (PCM). We evaluated 11 healthy women between 18 and 25 years old. We analyzed the following indices: Triangular index, Triangular interpolation of RR intervals and Poincarι plot (standard deviation of the instantaneous variability of the beat-to beat heart rate [SD1], standard deviation of long-term continuous RR interval variability and Ratio between the short - and long-term variations of RR intervals [SD1/SD2] ratio). HRV was recorded at seated rest for 10 min. The women quickly stood up from a seated position in up to 3 s and remained standing still for 15 min. HRV was recorded at the following periods: Rest, 0-5 min, 5-10 min and 10-15 min during standing. In the second protocol, the subject was exposed to auditory musical stimulation (Pachelbel-Canon in D) for 10 min at seated position before standing position. Shapiro-Wilk to verify normality of data and ANOVA for repeated measures followed by the Bonferroni test for parametric variables and Friedman's followed by the Dunn's posttest for non-parametric distributions. In the first protocol, all indices were reduced at 10-15 min after the volunteers stood up. In the protocol musical auditory stimulation, the SD1 index was reduced at 5-10 min after the volunteers stood up compared with the music period. The SD1/SD2 ratio was decreased at control and music period compared with 5-10 min after the volunteers stood up. Musical auditory stimulation attenuates the cardiac autonomic responses to the PCM.

A new technique to determine the correlation between the QT interval and heart-rate for control and SIDS babies

NASA Technical Reports Server (NTRS)

Sadeh, D.; Shannon, D. C.; Abboud, S.; Akselrod, S.; Cohen, R. J.

1987-01-01

The ability of the autonomic nervous system to alter the QT interval in response to heart rate changes is essential to cardiovascular control. An accurate way to determine the relation between QT intervals and their corresponding RR intervals is described. A computer algorithm measures the RR intervals using digital filtering and cross-correlating the QRS sections of consecutive waveforms. The QT intervals is calculated by choosing a section of, the ECG that includes the T wave and cross-correlating it with all the consecutive T waves. At least 4000 pairs of QT-RR intervals are computed for each subject and a best fit correlation function determines the relations between the QT and RR intervals. This technique enables to establish a precise correlation between RR and QT in order to distinguish between control and SIDS babies.

Quantitative Gait Markers and Incident Fall Risk in Older Adults

PubMed Central

Holtzer, Roee; Lipton, Richard B.; Wang, Cuiling

2009-01-01

Background Identifying quantitative gait markers of falls in older adults may improve diagnostic assessments and suggest novel intervention targets. Methods We studied 597 adults aged 70 and older (mean age 80.5 years, 62% women) enrolled in an aging study who received quantitative gait assessments at baseline. Association of speed and six other gait markers (cadence, stride length, swing, double support, stride length variability, and swing time variability) with incident fall rate was studied using generalized estimation equation procedures adjusted for age, sex, education, falls, chronic illnesses, medications, cognition, disability as well as traditional clinical tests of gait and balance. Results Over a mean follow-up period of 20 months, 226 (38%) of the 597 participants fell. Mean fall rate was 0.44 per person-year. Slower gait speed (risk ratio [RR] per 10 cm/s decrease 1.069, 95% confidence interval [CI] 1.001–1.142) was associated with higher risk of falls in the fully adjusted models. Among six other markers, worse performance on swing (RR 1.406, 95% CI 1.027–1.926), double-support phase (RR 1.165, 95% CI 1.026–1.321), swing time variability (RR 1.007, 95% CI 1.004–1.010), and stride length variability (RR 1.076, 95% CI 1.030–1.111) predicted fall risk. The associations remained significant even after accounting for cognitive impairment and disability. Conclusions Quantitative gait markers are independent predictors of falls in older adults. Gait speed and other markers, especially variability, should be further studied to improve current fall risk assessments and to develop new interventions. PMID:19349593

Human autonomic rhythms: vagal cardiac mechanisms in tetraplegic subjects

NASA Technical Reports Server (NTRS)

Koh, J.; Brown, T. E.; Beightol, L. A.; Ha, C. Y.; Eckberg, D. L.

1994-01-01

1. We studied eight young men (age range: 20-37 years) with chronic, clinically complete high cervical spinal cord injuries and ten age-matched healthy men to determine how interruption of connections between the central nervous system and spinal sympathetic motoneurones affects autonomic cardiovascular control. 2. Baseline diastolic pressures and R-R intervals (heart periods) were similar in the two groups. Slopes of R-R interval responses to brief neck pressure changes were significantly lower in tetraplegic than in healthy subjects, but slopes of R-R interval responses to steady-state arterial pressure reductions and increases were comparable. Plasma noradrenaline levels did not change significantly during steady-state arterial pressure reductions in tetraplegic patients, but rose sharply in healthy subjects. The range of arterial pressure and R-R interval responses to vasoactive drugs (nitroprusside and phenylephrine) was significantly greater in tetraplegic than healthy subjects. 3. Resting R-R interval spectral power at respiratory and low frequencies was similar in the two groups. During infusions of vasoactive drugs, low-frequency R-R interval spectral power was directly proportional to arterial pressure in tetraplegic patients, but was unrelated to arterial pressure in healthy subjects. Vagolytic doses of atropine nearly abolished both low- and respiratory-frequency R-R interval spectral power in both groups. 4. Our conclusions are as follows. First, since tetraplegic patients have significant levels of low-frequency arterial pressure and R-R interval spectral power, human Mayer arterial pressure waves may result from mechanisms that do not involve stimulation of spinal sympathetic motoneurones by brainstem neurones. Second, since in tetraplegic patients, low-frequency R-R interval spectral power is proportional to arterial pressure, it is likely to be mediated by a baroreflex mechanism. Third, since low-frequency R-R interval rhythms were nearly abolished by atropine in both tetraplegic and healthy subjects, these rhythms reflect in an important way rhythmic firing of vagal cardiac motoneurones.

Dynamic analysis of heart rate may predict subsequent ventricular tachycardia after myocardial infarction

NASA Technical Reports Server (NTRS)

Makikallio, T. H.; Seppanen, T.; Airaksinen, K. E.; Koistinen, J.; Tulppo, M. P.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

1997-01-01

Dynamics analysis of RR interval behavior and traditional measures of heart rate variability were compared between postinfarction patients with and without vulnerability to ventricular tachyarrhythmias in a case-control study. Short-term fractal correlation of heart rate dynamics was better than traditional measures of heart rate variability in differentiating patients with and without life-threatening arrhythmias.

An ECG electrode-mounted heart rate, respiratory rhythm, posture and behavior recording system.

PubMed

Yoshimura, Takahiro; Yonezawa, Yoshiharu; Maki, Hiromichi; Ogawa, Hidekuni; Ninomiya, Ishio; Morton Caldwell, W

2004-01-01

R-R interval, respiration rhythm, posture and behavior recording system has been developed for monitoring a patient's cardiovascular regulatory system in daily life. The recording system consists of three ECG chest electrodes, a variable gain instrumentation amplifier, a dual axis accelerometer, a low power 8-bit single-chip microcomputer and a 1024 KB EEPROM. The complete system is mounted on the chest electrodes. R-R interval and respiration rhythm are calculated by the R waves detected from the ECG. Posture and behavior such as walking and running are detected from the body movements recorded by the accelerometer. The detected data are stored by the EEPROM and, after recording, are downloaded to a desktop computer for analysis.

Cardiorespiratory interactions in patients with atrial flutter.

PubMed

Masè, Michela; Disertori, Marcello; Ravelli, Flavia

2009-01-01

Respiratory sinus arrhythmia (RSA) is generally known as the autonomically mediated modulation of the sinus node pacemaker frequency in synchrony with respiration. Cardiorespiratory interactions have been largely investigated during sinus rhythm, whereas little is known about interactions during reentrant arrhythmias. In this study, cardiorespiratory interactions at the atrial and ventricular level were investigated during atrial flutter (AFL), a supraventricular arrhythmia based on a reentry, by using cross-spectral analysis and computer modeling. The coherence and phase between respiration and atrial (gamma(AA)(2), phi(AA)) and ventricular (gamma(RR)(2), phi(RR)) interval series were estimated in 20 patients with typical AFL (68.0 +/- 8.8 yr) and some degree of atrioventricular (AV) conduction block. In all patients, atrial intervals displayed oscillations strongly coupled and in phase with respiration (gamma(AA)(2)= 0.97 +/- 0.05, phi(AA) = 0.71 +/- 0.31 rad), corresponding to a paradoxical lengthening of intervals during inspiration. The modulation pattern was frequency independent, with in-phase oscillations and short time delays (0.40 +/- 0.15 s) for respiratory frequencies in the range 0.1-0.4 Hz. Ventricular patterns were affected by AV conduction type. In patients with fixed AV conduction, ventricular intervals displayed oscillations strongly coupled (gamma(RR)(2)= 0.97 +/- 0.03) and in phase with respiration (phi(RR) = 1.08 +/- 0.80 rad). Differently, in patients with variable AV conduction, respiratory oscillations were secondary to Wencheback rhythmicity, resulting in a decreased level of coupling (gamma(RR)(2)= 0.50 +/- 0.21). Simulations with a simplified model of AV conduction showed ventricular patterns to originate from the combination of a respiratory modulated atrial input with the functional properties of the AV node. The paradoxical frequency-independent modulation pattern of atrial interval, the short time delays, and the complexity of ventricular rhythm characterize respiratory arrhythmia during AFL and distinguish it from normal RSA. These peculiar features can be explained by assuming a direct mechanical action of respiration on AFL reentrant circuit.

Predicting motion sickness during parabolic flight

NASA Technical Reports Server (NTRS)

Harm, Deborah L.; Schlegel, Todd T.

2002-01-01

BACKGROUND: There are large individual differences in susceptibility to motion sickness. Attempts to predict who will become motion sick have had limited success. In the present study, we examined gender differences in resting levels of salivary amylase and total protein, cardiac interbeat intervals (R-R intervals), and a sympathovagal index and evaluated their potential to correctly classify individuals into two motion sickness severity groups. METHODS: Sixteen subjects (10 men and 6 women) flew four sets of 10 parabolas aboard NASA's KC-135 aircraft. Saliva samples for amylase and total protein were collected preflight on the day of the flight and motion sickness symptoms were recorded during each parabola. Cardiovascular parameters were collected in the supine position 1-5 days before the flight. RESULTS: There were no significant gender differences in sickness severity or any of the other variables mentioned above. Discriminant analysis using salivary amylase, R-R intervals and the sympathovagal index produced a significant Wilks' lambda coefficient of 0.36, p=0.006. The analysis correctly classified 87% of the subjects into the none-mild sickness or the moderate-severe sickness group. CONCLUSIONS: The linear combination of resting levels of salivary amylase, high-frequency R-R interval levels, and a sympathovagal index may be useful in predicting motion sickness severity.

Predicting Motion Sickness During Parabolic Flight

NASA Technical Reports Server (NTRS)

Harm, Deborah L.; Schlegel, Todd T.

2002-01-01

Background: There are large individual differences in susceptibility to motion sickness. Attempts to predict who will become motion sick have had limited success. In the present study we examined gender differences in resting levels of salivary amylase and total protein, cardiac interbeat intervals (R-R intervals), and a sympathovagal index and evaluated their potential to correctly classify individuals into two motion sickness severity groups. Methods: Sixteen subjects (10 men and 6 women) flew 4 sets of 10 parabolas aboard NASA's KC-135 aircraft. Saliva samples for amylase and total protein were collected preflight on the day of the flight and motion sickness symptoms were recorded during each parabola. Cardiovascular parameters were collected in the supine position 1-5 days prior to the flight. Results: There were no significant gender differences in sickness severity or any of the other variables mentioned above. Discriminant analysis using salivary amylase, R-R intervals and the sympathovagal index produced a significant Wilks' lambda coefficient of 0.36, p= 0.006. The analysis correctly classified 87% of the subjects into the none-mild sickness or the moderate-severe sickness group. Conclusions: The linear combination of resting levels of salivary amylase, high frequency R-R interval levels, and a sympathovagal index may be useful in predicting motion sickness severity.

Validity of the Elite HRV Smartphone Application for Examining Heart Rate Variability in a Field-Based Setting.

PubMed

Perrotta, Andrew S; Jeklin, Andrew T; Hives, Ben A; Meanwell, Leah E; Warburton, Darren E R

2017-08-01

Perrotta, AS, Jeklin, AT, Hives, BA, Meanwell, LE, and Warburton, DER. Validity of the elite HRV smartphone application for examining heart rate variability in a field-based setting. J Strength Cond Res 31(8): 2296-2302, 2017-The introduction of smartphone applications has allowed athletes and practitioners to record and store R-R intervals on smartphones for immediate heart rate variability (HRV) analysis. This user-friendly option should be validated in the effort to provide practitioners confidence when monitoring their athletes before implementing such equipment. The objective of this investigation was to examine the relationship and validity between a vagal-related HRV index, rMSSD, when derived from a smartphone application accessible with most operating systems against a frequently used computer software program, Kubios HRV 2.2. R-R intervals were recorded immediately upon awakening over 14 consecutive days using the Elite HRV smartphone application. R-R recordings were then exported into Kubios HRV 2.2 for analysis. The relationship and levels of agreement between rMSSDln derived from Elite HRV and Kubios HRV 2.2 was examined using a Pearson product-moment correlation and a Bland-Altman Plot. An extremely large relationship was identified (r = 0.92; p < 0.0001; confidence interval [CI] 95% = 0.90-0.93). A total of 6.4% of the residuals fell outside the 1.96 ± SD (CI 95% = -12.0 to 7.0%) limits of agreement. A negative bias was observed (mean: -2.7%; CI 95% = -3.10 to -2.30%), whose CI 95% failed to fall within the line of equality. Our observations demonstrated differences between the two sources of HRV analysis. However, further research is warranted, as this smartphone HRV application may offer a reliable platform when assessing parasympathetic modulation.

Complexity quantification of cardiac variability time series using improved sample entropy (I-SampEn).

PubMed

Marwaha, Puneeta; Sunkaria, Ramesh Kumar

2016-09-01

The sample entropy (SampEn) has been widely used to quantify the complexity of RR-interval time series. It is a fact that higher complexity, and hence, entropy is associated with the RR-interval time series of healthy subjects. But, SampEn suffers from the disadvantage that it assigns higher entropy to the randomized surrogate time series as well as to certain pathological time series, which is a misleading observation. This wrong estimation of the complexity of a time series may be due to the fact that the existing SampEn technique updates the threshold value as a function of long-term standard deviation (SD) of a time series. However, time series of certain pathologies exhibits substantial variability in beat-to-beat fluctuations. So the SD of the first order difference (short term SD) of the time series should be considered while updating threshold value, to account for period-to-period variations inherited in a time series. In the present work, improved sample entropy (I-SampEn), a new methodology has been proposed in which threshold value is updated by considering the period-to-period variations of a time series. The I-SampEn technique results in assigning higher entropy value to age-matched healthy subjects than patients suffering atrial fibrillation (AF) and diabetes mellitus (DM). Our results are in agreement with the theory of reduction in complexity of RR-interval time series in patients suffering from chronic cardiovascular and non-cardiovascular diseases.

An easy-to-use technique to characterize cardiodynamics from first-return maps on ΔRR-intervals

NASA Astrophysics Data System (ADS)

Fresnel, Emeline; Yacoub, Emad; Freitas, Ubiratan; Kerfourn, Adrien; Messager, Valérie; Mallet, Eric; Muir, Jean-François; Letellier, Christophe

2015-08-01

Heart rate variability analysis using 24-h Holter monitoring is frequently performed to assess the cardiovascular status of a patient. The present retrospective study is based on the beat-to-beat interval variations or ΔRR, which offer a better view of the underlying structures governing the cardiodynamics than the common RR-intervals. By investigating data for three groups of adults (with normal sinus rhythm, congestive heart failure, and atrial fibrillation, respectively), we showed that the first-return maps built on ΔRR can be classified according to three structures: (i) a moderate central disk, (ii) a reduced central disk with well-defined segments, and (iii) a large triangular shape. These three very different structures can be distinguished by computing a Shannon entropy based on a symbolic dynamics and an asymmetry coefficient, here introduced to quantify the balance between accelerations and decelerations in the cardiac rhythm. The probability P111111 of successive heart beats without large beat-to-beat fluctuations allows to assess the regularity of the cardiodynamics. A characteristic time scale, corresponding to the partition inducing the largest Shannon entropy, was also introduced to quantify the ability of the heart to modulate its rhythm: it was significantly different for the three structures of first-return maps. A blind validation was performed to validate the technique.

Circadian rhythm in QT interval is preserved in mice deficient of potassium channel interacting protein 2.

PubMed

Gottlieb, Lisa A; Lubberding, Anniek; Larsen, Anders Peter; Thomsen, Morten B

2017-01-01

Potassium Channel Interacting Protein 2 (KChIP2) is suggested to be responsible for the circadian rhythm in repolarization duration, ventricular arrhythmias, and sudden cardiac death. We investigated the hypothesis that there is no circadian rhythm in QT interval in the absence of KChIP2. Implanted telemetric devices recorded electrocardiogram continuously for 5 days in conscious wild-type mice (WT, n = 9) and KChIP2 -/- mice (n = 9) in light:dark periods and in complete darkness. QT intervals were determined from all RR intervals and corrected for heart rate (QT 100 = QT/(RR/100) 1/2 ). Moreover, QT intervals were determined from complexes within the RR range of mean-RR ± 1% in the individual mouse (QT mean-RR ). We find that RR intervals are 125 ± 5 ms in WT and 123 ± 4 ms in KChIP2 -/- (p = 0.81), and QT intervals are 52 ± 1 and 52 ± 1 ms, respectively(p = 0.89). No ventricular arrhythmias or sudden cardiac deaths were observed. We find similar diurnal (light:dark) and circadian (darkness) rhythms of RR intervals in WT and KChIP2 -/- mice. Circadian rhythms in QT 100 intervals are present in both groups, but at physiological small amplitudes: 1.6 ± 0.2 and 1.0 ± 0.3 ms in WT and KChIP2 -/- , respectively (p = 0.15). A diurnal rhythm in QT 100 intervals was only found in WT mice. QT mean-RR intervals display clear diurnal and circadian rhythms in both WT and KChIP2 -/- . The amplitude of the circadian rhythm in QT mean-RR is 4.0 ± 0.3 and 3.1 ± 0.5 ms in WT and KChIP2 -/- , respectively (p = 0.16). In conclusion, KChIP2 expression does not appear to underlie the circadian rhythm in repolarization duration.

Effects of changing heart rate on electrophysiological and hemodynamic function in the dog.

PubMed

Hamlin, Robert L; Nakayama, Tomohiro; Nakayama, Hitomi; Carnes, Cynthia A

2003-03-14

Cardiovascular parameters were measured in dogs after RR interval was changed from 0.25 s to 1.2 s with atropine and graded doses of zatebradine, an I(f)-channel blocker. Left ventricular (LV) pre-ejection period (PEP), systemic vascular resistance, tau (an estimate of myocardial stiffness), PQ, QTc, dLVP/dt(max) and dLVP/dt(min), aortic pressure, and right atrial pressure did not change when each parameter was plotted against RR interval (r(2)'s < or = 0.5). LV end-diastolic pressure, stroke volume index, LV ejection time (ET), and QT all increased either linearly or curvilinearly as RR interval prolonged. Cardiac output index and PEP/ET decreased curvilinearly. When heart rate (HR) was fixed by pacing, and graded doses of zatebradine were given, changes in cardiovascular function were minimal. Thus zatebradine affects cardiovascular function principally by changing HR and not by affecting function directly. This study provides data on the effects of changing HR, alone, on cardiovascular parameters measured frequently during pharmacological and toxicological studies. It should prove useful when physiological variables, including HR, change, and there is need to know what change in HR, alone, contributes.

Agreement between Electrocardiogram and Heart Rate Meter Is Low for the Measurement of Heart Rate Variability during Exercise in Young Endurance Horses.

PubMed

Lenoir, Augustin; Trachsel, Dagmar S; Younes, Mohamed; Barrey, Eric; Robert, Céline

2017-01-01

Analysis of the heart rate variability (HRV) gains more and more importance in the assessment of training practice and welfare in equine industry. It relies on mathematical analyses of reliably and accurately measured variations in successive inter-beat intervals, measured as RR intervals. Nowadays, the RR intervals can be obtained through two different techniques: a heart rate meter (HRM) or an electrocardiogram (ECG). The agreement and reliability of these devices has not been fully assessed, especially for recordings during exercise. The purpose of this study was to assess the agreement of two commercially available devices using the two mentioned techniques (HRM vs ECG) for HRV analysis during a standardized exercise test. Simultaneous recordings obtained during light exercise and during canter with both devices were available for 36 horses. Data were compared using a Bland-Altman analysis and the Lin's coefficient. The agreement between the assessed HRV measures from the data obtained from the ECG and HRM was acceptable only for the mean RR interval and the mean heart rate. For the other studied measures (SDNN, root mean square of successive differences, SD1, SD2, low frequency, high frequency), the agreement between the devices was too poor for them to be considered as interchangeable in these recording conditions. The agreement tended also to be worse when speed of the exercise increased. Therefore, it is necessary to be careful when interpreting and comparing results of HRV analysis during exercise, as the results will depend upon recording devices. Furthermore, corrections and data processing included in the software of the devices affect largely the output used in the subsequent HRV analysis; this must be considered in the choice of the device.

QT Adaptation and Intrinsic QT Variability in Congenital Long QT Syndrome.

PubMed

Seethala, Srikanth; Singh, Prabhpreet; Shusterman, Vladimir; Ribe, Margareth; Haugaa, Kristina H; Němec, Jan

2015-12-16

Increased variability of QT interval (QTV) has been linked to arrhythmias in animal experiments and multiple clinical situations. Congenital long QT syndrome (LQTS), a pure repolarization disease, may provide important information on the relationship between delayed repolarization and QTV. Twenty-four-hour Holter monitor tracings from 78 genotyped congenital LQTS patients (52 females; 51 LQT1, 23 LQT2, 2 LQT5, 2 JLN, 27 symptomatic; age, 35.2±12.3 years) were evaluated with computer-assisted annotation of RR and QT intervals. Several models of RR-QT relationship were tested in all patients. A model assuming exponential decrease of past RR interval contributions to QT duration with 60-second time constant provided the best data fit. This model was used to calculate QTc and residual "intrinsic" QTV, which cannot be explained by heart rate change. The intrinsic QTV was higher in patients with long QTc (r=0.68; P<10(-4)), and in LQT2 than in LQT1/5 patients (5.65±1.28 vs 4.46±0.82; P<0.0002). Both QTc and intrinsic QTV were similar in symptomatic and asymptomatic patients (467±52 vs 459±53 ms and 5.10±1.19 vs 4.74±1.09, respectively). In LQTS patients, QT interval adaptation to heart rate changes occurs with time constant ≈60 seconds, similar to results reported in control subjects. Intrinsic QTV correlates with the degree of repolarization delay and might reflect action potential instability observed in animal models of LQTS. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

NASA Astrophysics Data System (ADS)

Nuryani, Nuryani; Satrio Nugroho, Anto

2017-11-01

Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

Quantitative comparison of entropy analysis of fetal heart rate variability related to the different stages of labor.

PubMed

Lim, Jongil; Kwon, Ji Young; Song, Juhee; Choi, Hosoon; Shin, Jong Chul; Park, In Yang

2014-02-01

The interpretation of the fetal heart rate (FHR) signal considering labor progression may improve perinatal morbidity and mortality. However, there have been few studies that evaluate the fetus in each labor stage quantitatively. To evaluate whether the entropy indices of FHR are different according to labor progression. A retrospective comparative study of FHR recordings in three groups: 280 recordings in the second stage of labor before vaginal delivery, 31 recordings in the first stage of labor before emergency cesarean delivery, and 23 recordings in the pre-labor before elective cesarean delivery. The stored FHR recordings of external cardiotocography during labor. Approximate entropy (ApEn) and sample entropy (SampEn) for the final 2000 RR intervals. The median ApEn and SampEn for the 2000 RR intervals showed the lowest values in the second stage of labor, followed by the emergency cesarean group and the elective cesarean group for all time segments (all P<0.001). Also, in the second stage of labor, the final 5 min of 2000 RR intervals had a significantly lower median ApEn (0.49 vs. 0.44, P=0.001) and lower median SampEn (0.34 vs. 0.29, P<0.001) than the initial 5 min of 2000 RR intervals. Entropy indices of FHR were significantly different according to labor progression. This result supports the necessity of considering labor progression when developing intrapartum fetal monitoring using the entropy indices of FHR. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cardiovascular Autonomic Dysfunction in Patients with Morbid Obesity

PubMed Central

de Sant Anna Junior, Maurício; Carneiro, João Regis Ivar; Carvalhal, Renata Ferreira; Torres, Diego de Faria Magalhães; da Cruz, Gustavo Gavina; Quaresma, José Carlos do Vale; Lugon, Jocemir Ronaldo; Guimarães, Fernando Silva

2015-01-01

Background Morbid obesity is directly related to deterioration in cardiorespiratory capacity, including changes in cardiovascular autonomic modulation. Objective This study aimed to assess the cardiovascular autonomic function in morbidly obese individuals. Methods Cross-sectional study, including two groups of participants: Group I, composed by 50 morbidly obese subjects, and Group II, composed by 30 nonobese subjects. The autonomic function was assessed by heart rate variability in the time domain (standard deviation of all normal RR intervals [SDNN]; standard deviation of the normal R-R intervals [SDNN]; square root of the mean squared differences of successive R-R intervals [RMSSD]; and the percentage of interval differences of successive R-R intervals greater than 50 milliseconds [pNN50] than the adjacent interval), and in the frequency domain (high frequency [HF]; low frequency [LF]: integration of power spectral density function in high frequency and low frequency ranges respectively). Between-group comparisons were performed by the Student’s t-test, with a level of significance of 5%. Results Obese subjects had lower values of SDNN (40.0 ± 18.0 ms vs. 70.0 ± 27.8 ms; p = 0.0004), RMSSD (23.7 ± 13.0 ms vs. 40.3 ± 22.4 ms; p = 0.0030), pNN50 (14.8 ± 10.4 % vs. 25.9 ± 7.2%; p = 0.0061) and HF (30.0 ± 17.5 Hz vs. 51.7 ± 25.5 Hz; p = 0.0023) than controls. Mean LF/HF ratio was higher in Group I (5.0 ± 2.8 vs. 1.0 ± 0.9; p = 0.0189), indicating changes in the sympathovagal balance. No statistical difference in LF was observed between Group I and Group II (50.1 ± 30.2 Hz vs. 40.9 ± 23.9 Hz; p = 0.9013). Conclusion morbidly obese individuals have increased sympathetic activity and reduced parasympathetic activity, featuring cardiovascular autonomic dysfunction. PMID:26536979

A Detailed Study of the Variable Stars in Five Galactic Globular Clusters: IC4499, NGC4833, NGC6171 (M107), NGC6402 (M14), and NGC6584

NASA Astrophysics Data System (ADS)

Murphy, Brian W.; Darragh, Andrew; Hettinger, Paul; Hibshman, Adam; Johnson, Elliott W.; Liu, Z. J.; Pajkos, Michael A.; Stephenson, Hunter R.; Vondersaar, John R.; Conroy, Kyle E.; McCombs, Thayne A.; Reinhardt, Erik D.; Toddy, Joseph

2015-08-01

We present the results of an extensive study intended to search for and properly classify the variable stars in five galactic globular clusters. Each of the five clusters was observed hundreds to thousands of times over a time span ranging from 2 to 4 years using the SARA 0.6m located at Cerro Tololo Interamerican Observatory. The images were analyzed using the image subtract method of Alard (2000) to identify and produce light curves of all variables found in each cluster. In total we identified 373 variables with 140 of these being newly discovered increasing the number of known variables stars in these clusters by 60%. Of the total we have identified 312 RR Lyrae variables (187 RR0, 18 RR01, 99 RR1, 8 RR2), 9 SX Phe stars, 6 Cepheid variables, 11 eclipsing variables, and 35 long period variables. For IC4499 we identified 64 RR0, 18 RR01, 14 RR1, 4 RR2, 1 SX Phe, 1 eclipsing binary, and 2 long period variables. For NGC4833 we identified 10 RR0, 7 RR1, 2 RR2, 6 SX Phe, 5 eclipsing binaries, and 9 long period variables. For NGC6171 (M107) we identified 13 RR0, 7 RR1, and 1 SX Phe. For NGC6402 (M14) we identified 52 RR0, 56 RR1, 1 RR2, 1 SX Phe, 6 Cepheids, 1 eclipsing binary, and 15 long period variables. For NGC6584 we identified 48 RR0, 15 RR1, 1 RR2, 5 eclipsing binaries, and 9 long period variables. Using the RR Lyrae variables we found the mean V magnitude of the horizontal branch to be VHB = ⟨V ⟩RR = 17.63, 15.51, 15.72, 17.13, and 16.37 magnitudes for IC4499, NGC4833, NGC6171 (M107), NGC6402 (M14), and NGC6584, respectively. From our extensive data set we were able to obtain sufficient temporal and complete phase coverage of the RR Lyrae variables. This has allowed us not only to properly classify each of the RR Lyrae variables but also to use Fourier decomposition of the light curves to further analyze the properties of the variable stars and hence physical properties of each clusters. In this poster we will give the temperature, radius, stellar mass, metallicity, and helium abundance of the set of RR Lyrae variable stars found in each of the five globular clusters.

A novel apparatus for non-contact measurement of heart rate variability: a system to prevent secondary exposure of medical personnel to toxic materials under biochemical hazard conditions, in monitoring sepsis or in predicting multiple organ dysfunction syndrome.

PubMed

Matsui, T; Arai, I; Gotoh, S; Hattori, H; Takase, B; Kikuchi, M; Ishihara, M

2005-10-01

The impaired balance of the low-frequency/high-frequency ratio obtained from spectral components of RR intervals can be a diagnostic test for sepsis. In addition, it is known that a reduction of heart rate variability (HRV) is useful in identifying septic patients at risk of the development of multiple organ dysfunction syndrome (MODS). We have reported a non-contact method using a microwave radar to monitor the heart and respiratory rates of a healthy person placed inside an isolator or of experimental animals exposed to toxic materials. With the purpose of preventing secondary exposure of medical personnel to toxic materials under biochemical hazard conditions, we designed a novel apparatus for non-contact measurement of HRV using a 1215 MHz microwave radar, a high-pass filter, and a personal computer. The microwave radar monitors only the small reflected waves from the subject's chest wall, which are modulated by the cardiac and respiratory motion. The high-pass filter enhances the cardiac signal and attenuates the respiratory signal. In a human trial, RR intervals derived from the non-contact apparatus significantly correlated with those derived from ECG (r=0.98, P<0.0001). The non-contact apparatus showed a similar power spectrum of RR intervals to that of ECG. Our non-contact HRV measurement apparatus appears promising for future pre-hospital monitoring of septic patients or for predicting MODS patients, inside isolators or in the field for mass casualties under biochemical hazard circumstances.

A Detailed Survey of Pulsating Variables in Five Globular Clusters (Abstract)

NASA Astrophysics Data System (ADS)

Murphy, B. W.

2016-12-01

(Abstract only) Globular clusters are ideal laboratories for conducting a stellar census. Of particular interest are pulsating variables, which provide astronomers with a tool to probe the properties of the stars and the cluster. We observed each of five globular clusters hundreds to thousands of times over a time span ranging from 2 to 4 years in B, V, and I filters using the SARA 0.6-meter telescope located at Cerro Tololo Interamerican Observatory and the 0.9-meter telescope located at Kitt Peak, Arizona. The images were analyzed using difference image analysis to identify and produce light curves of all variables found in each cluster. In total we identified 377 variables with 140 of these being newly discovered increasing the number of known variables stars in these clusters by 60%. Of the total we have identified 319 RR Lyrae variables (193 RR0, 18 RR01, 101 RR1, 7 RR2), 9 SX Phe stars, 5 Cepheid variables, 11 eclipsing variables, and 33 long period variables. For IC4499 we identified 64 RR0, 18 RR01, 14 RR1, 4 RR2, 1 SX Phe, 1 eclipsing binary, and 2 long period variables. For NGC4833 we identified 10 RR0, 7 RR1, 3 RR2, 6 SX Phe, 5 eclipsing binaries, and 9 long period variables. For NGC6171 (M107) we identified 14 RR0, 7 RR1, and 1 SX Phe. For NGC6402 (M14) we identified 55 RR0, 57 RR1, 1 RR2, 1 SX Phe, 6 Cepheids, 1 eclipsing binary, and 15 long period variables. For NGC6584 we identified 50 RR0, 16 RR1, 4 eclipsing binaries, and 7 long period variables. From our extensive data set we were able to obtain sufficient temporal and complete phase coverage of the RR Lyrae variables. This has allowed us not only to properly classify each of the RR Lyrae variables but also to use Fourier decomposition of the B, V, and I light curves to further analyze the properties of the variable stars and hence the physical properties of each globular cluster.

Occupational exposures and cancer of the colon and rectum.

PubMed

Gerhardsson de Verdier, M; Plato, N; Steineck, G; Peters, J M

1992-01-01

The associations between occupational risks and colorectal cancer were examined in a Swedish population-based, case-referent study. The study was performed in Stockholm in 1986-1988 and included 569 cases and 512 referents. Relative risks (RRs) with 95% confidence intervals were calculated for different occupations/chemicals. Elevated risks of colon cancer were found among male petrol station/automobile repair workers (RR = 2.3, 0.8-6.6) and among males exposed to asbestos (RR = 1.8, 0.9-3.6), while elevated risks of rectal cancer were found among males exposed to soot (RR = 2.2, 1.1-4.3), asbestos (RR = 2.2, 1.0-4.7), cutting fluids/oils (RR = 2.1, 1.1-4.0), and combustion gases from coal/coke/wood (RR = 1.9, 1.0-3.7). However, due to a high correlation between the above-mentioned variables and the few exposed subjects, it is difficult to separate their effects properly. These analyses were adjusted for age. Further adjustments for diet, body mass, and physical activity had little or no influence on the results.

Work, social support and leisure protect the elderly from functional loss: EPIDOSO study.

PubMed

d'Orsi, Eleonora; Xavier, André Junqueira; Ramos, Luiz Roberto

2011-08-01

To identify risk factors for functional capacity loss in elderly people. Epidoso (Epidemiology of the Elderly) cohort study with elderly people living in São Paulo (Southeastern Brazil). A total of 326 participants in the first interview (1991-1992) who were independent or had mild dependence (one or two activities of daily living) were selected. Those who presented functional loss in the second (1994-1995) or third interviews (1998-1999) were compared to those who did not present it. The incidence of functional loss was calculated according to sociodemographic variables, life habits, cognitive status, morbidity, hospitalization, self-rated health, tooth loss, social support and leisure activities. Crude and adjusted relative risks with 95% confidence intervals were estimated through bivariate and multiple analyses with Poisson regression. The criterion for the inclusion of the variables in the model was p < 0.20 and for exclusion, p > 0.10. The incidence of functional loss was 17.8% (13.6; 21.9). The risk factors in the final model were: age group 70-74 years RR=1.9 (0.9;3.9); age group 75-79 years RR=2.8 (1.4;5.5); age group 80 years or older RR=5.4 (3.0;9.6); score in the mini-mental state examination <24 RR=1.8 (1.1;2.9); asthma RR=2.3 (1.3;3.9); hypertension RR=1.7 (1.1;2.6); and diabetes RR=1.7 (0.9;3.0). The protective factors were: paid work RR=0.3 (0.1;1.0); monthly relationship with friends RR=0.5 (0.3;0.8); watching TV RR=0.5 (0.3;0.9); and handcrafting RR=0.7 (0.4;1.0). The prevention of functional loss should include adequate control of chronic diseases, like hypertension, asthma and diabetes, as well as cognitive stimulation. Work, leisure and relationships with friends should be valued due to their protective effect.

[Population characteristics and impact on heart rate variability, heart rate and blood pressure of passive smoking].

PubMed

Zhao, Jing; He, Fei; Hu, Da-yi; Ding, Rong-jing; Yu, Xiao-jun; Wang, Long; Zhang, Ping; Li, Xue-bin; Guo, Ji-hong; Liu, Wen-ling; Li, Cui-lan; Li, Lei; Gao, Chuan-yu; Zhao, Luo-sha; Chu, Ying-jie; Huang, Zhen-wen; Wei, Jing-han; Hua, Shao-hua; Liu, Rui-yun; Zhuang, Xiao-feng

2013-05-01

To investigate the basic characteristics of passive smoking population, and the impact of passive smoking on heart rate variability, heart rate and blood pressure. Eighty-six passive smokers [mean age: (52.4 ± 7.6) years] were recruited from patients and their relatives who visited cardiovascular outpatient department and excluded structural heart disease between June 2010 and June 2012, 80 normal subjects who were not exposed to smoking served as controls. Questionnaire survey, 24 hours ambulatory electrocardiogram examination and blood pressure measurement were performed in all recruited subjects. (1) Non-marriage rate [18.60% (16/86) vs. 3.75% (3/80), P < 0.01] was significantly higher while education level were significantly lower in passive smoking group than in control group. Passive smokers were more likely service industry workers [29.07% (25/86) vs. 15.00% (12/80), P < 0.05] and had longer daily working time [(7.56 ± 1.24) h vs. (6.02 ± 0.96) h, P < 0.01], and were less likely to be professional technology industry employers [20.93% (18/86) vs. 36.25% (29/80), P < 0.05] and managers [13.95% (12/86) vs. 38.75% (31/80), P < 0.01] compared to controls. The main place of passive smoking was workplace (67.44%, 58/86), entertainment venues (63.95%,55/86), restaurants (48.84%, 42/86). (2) Standard of the normal sinus RR intervals (SDNN), the normal consecutive sinus RR interval difference between the root-mean-square (rMSSD) and adjacent the difference between the RR interval>50 ms the number of share the percentage (PNN50) were significantly lower in passive smoking group than in the control group (all P < 0.05). Every 5 min average of the standard deviation of sinus RR cycle (SDNN index) and 24 h every 5 min sinus RR interval mean standard deviation (SDANN) were similar between the 2 groups (all P > 0.05). Ultra-low-frequency power (VLF), low frequency power (LF), high frequency power (HF) and LF/HF were significantly lower in passive smoking group than in the control group (all P < 0.01). (3) Heart rate and diastolic blood pressure were significantly higher in passive smoking group than in control group (all P < 0.05) while systolic blood pressure was similar between the 2 groups (P > 0.05). Marriage status, education level, profession and daily working time are independent determinants for passive smoking. Passive smoking mainly occurred in the workplace, entertainment venues and restaurants. Passive smoking is linked with reduced heart rate variability, increased 24 h average heart rate and diastolic blood pressure.

Exercise training improves autonomic profiles in patients with Charcot-Marie-Tooth disease.

PubMed

El Mhandi, Lhassan; Pichot, Vincent; Calmels, Paul; Gautheron, Vincent; Roche, Frédéric; Féasson, Léonard

2011-11-01

The effect of an interval exercise training (ITE) program on heart rate variability (HRV) was studied in 8 patients with Charcot-Marie-Tooth (CMT) disease and 8 healthy controls. At baseline, all subjects underwent ambulatory 24-hour Holter electrocardiographic (ECG) monitoring to evaluate HRV. HRV analysis was repeated on CMT patients after they completed a 24-week ITE program on a cycle ergometer. Before exercise, all HRV indices were lower in patients compared with controls, and the difference reached statistical significance for pNN50 (percent of differences between adjacent R-R intervals exceeding 50 ms). After ITE, time- and frequency-domain indices were significantly improved, particularly at night (+8% mean R-R interval, +95% pNN50, 52% reduction in low/high-frequency ratio). We observed significant increases in some of the time and frequency parameters, and values sometimes exceeded those of controls at baseline. Our results suggest that ITE improves HRV modulation in CMT patients by enhancing parasympathetic activity. Copyright © 2011 Wiley Periodicals, Inc.

Reduced heart rate variability and vagal tone in anxiety: trait versus state, and the effects of autogenic training.

PubMed

Miu, Andrei C; Heilman, Renata M; Miclea, Mircea

2009-01-28

This study investigated heart rate variability (HRV) in healthy volunteers that were selected for extreme scores of trait anxiety (TA), during two opposite psychophysiological conditions of mental stress, and relaxation induced by autogenic training. R-R intervals, HF and LF powers, and LF/HF ratios were derived from short-term electrocardiographic recordings made during mental stress and relaxation by autogenic training, with respiratory rate and skin conductance being controlled for in all the analyses. The main finding was that high TA was associated with reduced R-R intervals and HF power across conditions. In comparison to mental stress, autogenic training increased HRV and facilitated the vagal control of the heart. There were no significant effects of TA or the psychophysiological conditions on LF power, or LF/HF ratio. These results support the view that TA, which is an important risk factor for anxiety disorders and predictor of cardiovascular morbidity and mortality, is associated with autonomic dysfunction that seems likely to play a pathogenetic role in the long term.

QT-RR relationships and suitable QT correction formulas for halothane-anesthetized dogs.

PubMed

Tabo, Mitsuyasu; Nakamura, Mikiko; Kimura, Kazuya; Ito, Shigeo

2006-10-01

Several QT correction (QTc) formulas have been used for assessing the QT liability of drugs. However, they are known to under- and over-correct the QT interval and tend to be specific to species and experimental conditions. The purpose of this study was to determine a suitable formula for halothane-anesthetized dogs highly sensitive to drug-induced QT interval prolongation. Twenty dogs were anesthetized with 1.5% halothane and the relationship between the QT and RR intervals were obtained by changing the heart rate under atrial pacing conditions. The QT interval was corrected for the RR interval by applying 4 published formulas (Bazett, Fridericia, Van de Water, and Matsunaga); Fridericia's formula (QTcF = QT/RR(0.33)) showed the least slope and lowest R(2) value for the linear regression of QTc intervals against RR intervals, indicating that it dissociated changes in heart rate most effectively. An optimized formula (QTcX = QT/RR(0.3879)) is defined by analysis of covariance and represents a correction algorithm superior to Fridericia's formula. For both Fridericia's and the optimized formula, QT-prolonging drugs (d,l-sotalol, astemizole) showed QTc interval prolongation. A non-QT-prolonging drug (d,l-propranolol) failed to prolong the QTc interval. In addition, drug-induced changes in QTcF and QTcX intervals were highly correlated with those of the QT interval paced at a cycle length of 500 msec. These findings suggest that Fridericia's and the optimized formula, although the optimized is a little bit better, are suitable for correcting the QT interval in halothane-anesthetized dogs and help to evaluate the potential QT prolongation of drugs with high accuracy.

Artificial neural network for normal, hypertensive, and preeclamptic pregnancy classification using maternal heart rate variability indexes.

PubMed

Tejera, Eduardo; Jose Areias, Maria; Rodrigues, Ana; Ramõa, Ana; Manuel Nieto-Villar, Jose; Rebelo, Irene

2011-09-01

A model construction for classification of women with normal, hypertensive and preeclamptic pregnancy in different gestational ages using maternal heart rate variability (HRV) indexes. In the present work, we applied the artificial neural network for the classification problem, using the signal composed by the time intervals between consecutive RR peaks (RR) (n = 568) obtained from ECG records. Beside the HRV indexes, we also considered other factors like maternal history and blood pressure measurements. The obtained result reveals sensitivity for preeclampsia around 80% that increases for hypertensive and normal pregnancy groups. On the other hand, specificity is around 85-90%. These results indicate that the combination of HRV indexes with artificial neural networks (ANN) could be helpful for pregnancy study and characterization.

Entropy Information of Cardiorespiratory Dynamics in Neonates during Sleep.

PubMed

Lucchini, Maristella; Pini, Nicolò; Fifer, William P; Burtchen, Nina; Signorini, Maria G

2017-05-01

Sleep is a central activity in human adults and characterizes most of the newborn infant life. During sleep, autonomic control acts to modulate heart rate variability (HRV) and respiration. Mechanisms underlying cardiorespiratory interactions in different sleep states have been studied but are not yet fully understood. Signal processing approaches have focused on cardiorespiratory analysis to elucidate this co-regulation. This manuscript proposes to analyze heart rate (HR), respiratory variability and their interrelationship in newborn infants to characterize cardiorespiratory interactions in different sleep states (active vs. quiet). We are searching for indices that could detect regulation alteration or malfunction, potentially leading to infant distress. We have analyzed inter-beat (RR) interval series and respiration in a population of 151 newborns, and followed up with 33 at 1 month of age. RR interval series were obtained by recognizing peaks of the QRS complex in the electrocardiogram (ECG), corresponding to the ventricles depolarization. Univariate time domain, frequency domain and entropy measures were applied. In addition, Transfer Entropy was considered as a bivariate approach able to quantify the bidirectional information flow from one signal (respiration) to another (RR series). Results confirm the validity of the proposed approach. Overall, HRV is higher in active sleep, while high frequency (HF) power characterizes more quiet sleep. Entropy analysis provides higher indices for SampEn and Quadratic Sample entropy (QSE) in quiet sleep. Transfer Entropy values were higher in quiet sleep and point to a major influence of respiration on the RR series. At 1 month of age, time domain parameters show an increase in HR and a decrease in variability. No entropy differences were found across ages. The parameters employed in this study help to quantify the potential for infants to adapt their cardiorespiratory responses as they mature. Thus, they could be useful as early markers of risk for infant cardiorespiratory vulnerabilities.

Poincaré plot analysis of autocorrelation function of RR intervals in patients with acute myocardial infarction.

PubMed

Chuang, Shin-Shin; Wu, Kung-Tai; Lin, Chen-Yang; Lee, Steven; Chen, Gau-Yang; Kuo, Cheng-Deng

2014-08-01

The Poincaré plot of RR intervals (RRI) is obtained by plotting RRIn+1 against RRIn. The Pearson correlation coefficient (ρRRI), slope (SRRI), Y-intercept (YRRI), standard deviation of instantaneous beat-to-beat RRI variability (SD1RR), and standard deviation of continuous long-term RRI variability (SD2RR) can be defined to characterize the plot. Similarly, the Poincaré plot of autocorrelation function (ACF) of RRI can be obtained by plotting ACFk+1 against ACFk. The corresponding Pearson correlation coefficient (ρACF), slope (SACF), Y-intercept (YACF), SD1ACF, and SD2ACF can be defined similarly to characterize the plot. By comparing the indices of Poincaré plots of RRI and ACF between patients with acute myocardial infarction (AMI) and patients with patent coronary artery (PCA), we found that the ρACF and SACF were significantly larger, whereas the RMSSDACF/SDACF and SD1ACF/SD2ACF were significantly smaller in AMI patients. The ρACF and SACF correlated significantly and negatively with normalized high-frequency power (nHFP), and significantly and positively with normalized very low-frequency power (nVLFP) of heart rate variability in both groups of patients. On the contrary, the RMSSDACF/SDACF and SD1ACF/SD2ACF correlated significantly and positively with nHFP, and significantly and negatively with nVLFP and low-/high-frequency power ratio (LHR) in both groups of patients. We concluded that the ρACF, SACF, RMSSDACF/SDACF, and SD1ACF/SD2ACF, among many other indices of ACF Poincaré plot, can be used to differentiate between patients with AMI and patients with PCA, and that the increase in ρACF and SACF and the decrease in RMSSDACF/SDACF and SD1ACF/SD2ACF suggest an increased sympathetic and decreased vagal modulations in both groups of patients.

Atrial Premature Depolarization-Induced Changes in QRS and T Wave Morphology on Resting Electrocardiograms in Horses.

PubMed

Broux, B; De Clercq, D; Decloedt, A; Van Der Vekens, N; Verheyen, T; Ven, S; Pardon, B; van Loon, G

2016-07-01

The electrocardiographic differentiation between atrial (APDs) and ventricular (VPDs) premature depolarizations is important. P wave prematurity and normal QRS and T wave morphology generally are used as discriminating criteria for APDs. The aim of this study was to determine whether P, Q, R, S, and T wave amplitude, PQ interval, QRS and P wave duration and P and T wave morphology differ between APDs and sinus beats. To determine the relationship between the RR coupling interval and the change in S wave amplitude between sinus beats and APDs. Case-control study. From a modified base-apex configuration of 30 horses with APDs at rest, sinus beat and APD associated preceding RR interval, P, PQ and QRS duration and P, R, S, and T wave amplitudes were measured. Linear mixed models and logistic regression were used to determine the effect of APDs on the ECG variables studied. In comparison to sinus beats, APDs were associated with a significant (P < .001) change in P amplitude (-0.03 ± 0.01 mV) and increase in S (0.20 ± 0.02 mV) and T (0.08 ± 0.03 mV) amplitude. PQ (-20.3 ± 5.2 ms) and RR (-519 ± 14 ms) interval and P duration (-21.1 ± 3.0 ms) decreased (P < .001). APDs were significantly associated with a singular positive P wave (OR: 11.0, P < .001) and were more likely to have a monophasic positive T wave (OR: 9.2, P < .001). A smaller RR coupling interval was associated with an increased relative difference in S amplitude (P < .01). Atrial premature depolarizations may lead to changes in QRS and T wave morphology. Knowledge of these changes is important to avoid interpreting certain APDs as VPDs. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Heart Rate Variability Can Be Used to Estimate Sleepiness-related Decrements in Psychomotor Vigilance during Total Sleep Deprivation

PubMed Central

Chua, Eric Chern-Pin; Tan, Wen-Qi; Yeo, Sing-Chen; Lau, Pauline; Lee, Ivan; Mien, Ivan Ho; Puvanendran, Kathiravelu; Gooley, Joshua J.

2012-01-01

Study Objectives: To assess whether changes in psychomotor vigilance during sleep deprivation can be estimated using heart rate variability (HRV). Design: HRV, ocular, and electroencephalogram (EEG) measures were compared for their ability to predict lapses on the Psychomotor Vigilance Task (PVT). Setting: Chronobiology and Sleep Laboratory, Duke-NUS Graduate Medical School Singapore. Participants: Twenty-four healthy Chinese men (mean age ± SD = 25.9 ± 2.8 years). Interventions: Subjects were kept awake continuously for 40 hours under constant environmental conditions. Every 2 hours, subjects completed a 10-minute PVT to assess their ability to sustain visual attention. Measurements and Results: During each PVT, we examined the electrocardiogram (ECG), EEG, and percentage of time that the eyes were closed (PERCLOS). Similar to EEG power density and PERCLOS measures, the time course of ECG RR-interval power density in the 0.02- 0.08-Hz range correlated with the 40-hour profile of PVT lapses. Based on receiver operating characteristic curves, RR-interval power density performed as well as EEG power density at identifying a sleepiness-related increase in PVT lapses above threshold. RR-interval power density (0.02-0.08 Hz) also classified subject performance with sensitivity and specificity similar to that of PERCLOS. Conclusions: The ECG carries information about a person's vigilance state. Hence, HRV measures could potentially be used to predict when an individual is at increased risk of attentional failure. Our results suggest that HRV monitoring, either alone or in combination with other physiologic measures, could be incorporated into safety devices to warn drowsy operators when their performance is impaired. Citation: Chua ECP; Tan WQ; Yeo SC; Lau P; Lee I; Mien IH; Puvanendran K; Gooley JJ. Heart rate variability can be used to estimate sleepiness-related decrements in psychomotor vigilance during total sleep deprivation. SLEEP 2012;35(3):325-334. PMID:22379238

Indexes of temporal myocardial repolarization dispersion and sudden cardiac death in heart failure: any difference?

PubMed

Piccirillo, Gianfranco; Rossi, Pietro; Mitra, Marilena; Quaglione, Raffaele; Dell'Armi, Annalaura; Di Barba, Daniele; Maisto, Damiana; Lizio, Andrea; Barillà, Francesco; Magrì, Damiano

2013-03-01

The QT variability index, calculated between Q- and the T-wave end (QTend VI), is an index of temporal myocardial repolarization lability associated with sudden cardiac death (SCD) in chronic heart failure (CHF). Little is known about temporal variability in the other two temporal myocardial repolarization descriptors obtained from Q-Tpeak and Tpeak -Tend intervals. We therefore investigated differences between these indexes in patients with CHF who died suddenly and in those who survived with a left ventricular ejection fraction (LVEF) ≤35% or >35%. We selected 127 ECG and systolic blood pressure (SPB) recordings from outpatients with CHF all of whom had been followed up for 30 months. We calculated RR and SPB variability by power spectral analysis and QTend VI, QTpeak VI, Tpeak Tend VI. We then subdivided data patients into three groups SCD, LVEF ≤ 35%, and LVEF > 35%. The LVEF was higher in the SCD than in the LVEF ≤ 35% group, whereas no difference was found between the SCD and LVEF > 35% groups. QTend VI, QTpeak VI, and Tpeak Tend VI were higher in the SCD and LVEF ≤ 35% groups than in the LVEF > 35% group. Multivariate analysis detected a negative relationship between all repolarization variability indexes, low frequency obtained from RR intervals and LVEF. Our data show that variability in the first (QTpeak VI) and second halves of the QT interval (Tpeak -Tend VI) significantly contributes to the QTend VI in patients with CHF. Further studies should investigate whether these indexes might help stratify the risk of SCD in patients with a moderately depressed LVEF. ©2012, Wiley Periodicals, Inc.

[Association of cardiovascular autonomic neuropathy and prolonged QT interval with cardiovascular morbidity and mortality in patients with type 2 diabetes mellitus].

PubMed

Ticse Aguirre, Ray; Villena, Jaime E

2011-03-01

In order to evaluate the relationship between cardiovascular autonomic neuropathy and corrected QT interval (QTc) with cardiovascular morbidity and mortality in patients with type 2 diabetes mellitus, we followed up for 5 years 67 patients attending the outpatient Endocrinology Service. 82% completed follow-up and cardiovascular events occurred in 16 patients. We found that long QTc interval was the only variable significantly associated with cardiovascular morbidity and mortality in the multiple logistic regression analysis (RR: 13.56, 95% CI: 2.01-91.36) (p = 0.0074).

High N-Terminal Pro-B-Type Natriuretic Peptide Levels Are Associated with Reduced Heart Rate Variability in Acute Myocardial Infarction

PubMed Central

Lorgis, Luc; Moreau, Daniel; Mock, Laurent; Daumas, Bernadette; Potard, Daniel; Touzery, Claude; Cottin, Yves; Zeller, Marianne

2012-01-01

Aim We investigated the relationships between the autonomic nervous system, as assessed by heart rate variability (HRV) and levels of N-terminal Pro-B-type Natriuretic Peptide (Nt-proBNP) in patients with acute myocardial infarction (MI). Methods and Results The mean of standard deviation of RR intervals (SDNN), the percentage of RR intervals with >50 ms variation (pNN50), square root of mean squared differences of successive RR intervals (rMSSD), and frequency domain parameters (total power (TP), high frequency and low frequency power ratio (LF/HF)) were assessed by 24 h Holter ECG monitoring. 1018 consecutive patients admitted <24 h for an acute MI were included. Plasma Nt-proBNP (Elecsys, Roche) was measured from blood samples taken on admission. The median (IQR) Nt-proBNP level was 681(159–2432) pmol/L. Patients with the highest quartile of Nt-proBNP were older, with higher rate of risk factors and lower ejection fraction. The highest Nt-proBNP quartile group had the lowest SDNN, LF/HF and total power but similar pNN50 and rMSSD levels. Nt-proBNP levels correlated negatively with SDNN (r = −0.19, p<0.001), LF/HF (r = −0.37, p<0.001), and LF (r = −0.29, p<0.001) but not HF (r = −0.043, p = 0.172). Multiple regression analysis showed that plasma propeptide levels remained predictive of LF/HF (B(SE) = −0.065(0.015), p<0.001)), even after adjustment for confounders. Conclusions In conclusion, our population-based study highlights the importance of Nt-proBNP levels to predict decreased HRV after acute MI. PMID:23071500

Augmented baroreflex heart rate gain after moderate-intensity, dynamic exercise

NASA Technical Reports Server (NTRS)

Halliwill, J. R.; Taylor, J. A.; Hartwig, T. D.; Eckberg, D. L.

1996-01-01

The occurrence of a sustained vasodilation and hypotension after acute, dynamic exercise suggests that exercise may alter arterial baroreflex mechanisms. Therefore, we assessed systemic hemodynamics, baroreflex regulation of heart rate, and cardiac vagal tone after 60 min of cycling at 60% peak oxygen consumption in 12 healthy, untrained men and women (ages 21-28 yr). We derived sigmoidal carotid-cardiac baroreflex relations by measurement of R-R interval changes induced by ramped, stepwise, R-wave-triggered changes in external neck pressure from 40 to -65 mmHg. We estimated tonic cardiac vagal control with power spectral analysis of R-R interval variability in the respiratory frequency band (0.2-0.3 Hz) during frequency- and tidal volume-controlled breathing. Both mean arterial pressure and total peripheral resistance were reduced postexercise [pressure: from 86 +/- 2 (mean +/- SE) to 81 +/- 2 mmHg; resistance: from 23 +/- 2 to 16 +/- 1 units; both P < 0.05]. Cardiac output was increased postexercise (from 3.9 +/- 0.3 to 5.5 +/- 0.5 l/min, P < 0.05). Both slope and range of the carotid-cardiac baroreflex relation were increased postexercise (slope: from 4.7 +/- 0.7 to 6.1 +/- 0.9 ms/mmHg; range: from 186 +/- 23 to 238 +/- 30 ms, P < 0.05). Respiratory R-R interval variability (cardiac vagal tone) was not changed at any time after exercise, whereas heart rate and plasma norepinephrine levels were elevated. Thus moderate-intensity, dynamic exercise increases heart rate and cardiac output, reduces peripheral vascular resistance, and augments baroreflex responsiveness. Our data suggest that augmented baroreflex heart rate gain restrains rather than contributes to postexercise hypotension, which appears to be mediated predominately by vasodilation.

Poincaré plot analysis of ultra-short-term heart rate variability during recovery from exercise in physically active men.

PubMed

Gomes, Rayana L; Marques Vanderlei, Luiz C; Garner, David M; Ramos Santana, Milana D; de Abreu, Luiz C; Valenti, Vitor E

2017-04-26

Recently there has been increasing interest in the study of ultra-short- term heart rate variability (HRV) in sports performance and exercise physiology. In order to improve standardization of this specific analysis, we evaluated the ultra-short-term HRV analysis through SD1Poincaré index to identify exercise induced responses. We investigated 35 physically active men aged between 18 and 35 years old. Volunteers performed physical exercise on treadmill with intensity of 6.0 km / hour + 1% slope in the first five minutes for physical "warming up." This was followed by 25 minutes with intensity equivalent to 60% of Vmax, with the same slope according to the Conconi threshold. HRV was analyzed in the following periods: the five-minute period before the exercise and the five-minute period immediately after the exercise, the five minutes were divided into five segments of 60 RR intervals. Ultra-short-term RMSSD and SD1 analysis were performed. Ultra-short-term RMSSD and SD1 were significantly (p<0.0001) reduced during the initial five minutes divided into five segments of 60 RR intervals compared to (at rest) control. Heart rate was significantly (p<0.0001) increased 1 min and 3 min immediately after exercise compared to (at rest) control. At rest ultra-short-term SD1 presented significant correlation with short-term (256 RR intervals) RMSSD (r=0.78; p<0.0001), HF (r=0.574; p=0.0007) and SD1 (r=0.78; p<0.0001). Additionally, visual analysis with the Poincaré plot detected changes in HRV after exercise. Ultra-short-term HRV analysis through Poincaré plot identified heart rate autonomic responses induced by aerobic exercise.

Multiband Fourier Analysis and Interstellar Reddening of the Variable Stars in the Globular Cluster NGC 6402 (M14)

NASA Astrophysics Data System (ADS)

Weinschenk, Sedrick; Murphy, Brian; Villiger, Nathan J.

2018-01-01

We present a detailed study of the variable stars in the globular cluster NGC 6402 (M14). Approximately 1500 B and V band images were collected from July 2016 to August 2017 using the SARA Consortium Jacobus Kaptyen 1-meter telescope located in the Canary Islands. Using difference image analysis, we were able to identify 145 probable variable stars, confirming the 133 previously known variables and adding 12 new variables. The variables consisted of 117 RR Lyrae stars, 18 long period variables, 2 eclipsing variables, 6 Cepheid variables, and 2 SX Phoenix variables. Of the RR Lyrae variables 55 were of fundamental mode RR0 stars, of which 18 exhibited the Blazhko effect, 57 were of 1st overtone RR1, of which 7 appear to exhibit the Blazhko effect, 1 2nd overtone RR2, and 2 double mode variables. We found an average period of 0.59016 days for RR0 stars and 0.30294 days for RR1 stars. Using the multiband light curves of both the RR0 and RR1 variables we found an average E(B-V) of 0.604 with a scatter of 0.15 magnitudes. Using Fourier decomposition of the RR Lyrae light curves we also determined the metallicity and distance of the NGC 6402.

AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS

PubMed Central

Báez, San Martín E.; Von Oetinger, A.; Cañas, Jamett R.; Ramírez, Campillo R.

2013-01-01

The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability – SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW. PMID:24744476

Autonomic control of heart rate after exercise in trained wrestlers.

PubMed

Henríquez, Olguín C; Báez, San Martín E; Von Oetinger, A; Cañas, Jamett R; Ramírez, Campillo R

2013-06-01

The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability - SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW.

Comparison of spontaneous vs. metronome-guided breathing on assessment of vagal modulation using RR variability.

PubMed

Bloomfield, D M; Magnano, A; Bigger, J T; Rivadeneira, H; Parides, M; Steinman, R C

2001-03-01

R-R interval variability (RR variability) is increasingly being used as an index of autonomic activity. High-frequency (HF) power reflects vagal modulation of the sinus node. Since vagal modulation occurs at the respiratory frequency, some investigators have suggested that HF power cannot be interpreted unless the breathing rate is controlled. We hypothesized that HF power during spontaneous breathing would not differ significantly from HF power during metronome-guided breathing. We measured HF power during spontaneous breathing in 20 healthy subjects and 19 patients with heart disease. Each subject's spontaneous breathing rate was determined, and the calculation of HF power was repeated with a metronome set to his or her average spontaneous breathing rate. There was no significant difference between the logarithm of HF power measured during spontaneous and metronome-guided breathing [4.88 +/- 0.29 vs. 5.29 +/- 0.30 ln(ms(2)), P = 0.32] in the group as a whole and when patients and healthy subjects were examined separately. We did observe a small (9.9%) decrease in HF power with increasing metronome-guided breathing rates (from 9 to 20 breaths/min). These data indicate that HF power during spontaneous and metronome-guided breathing differs at most by very small amounts. This variability is several logarithmic units less than the wide discrepancies observed between healthy subjects and cardiac patients with a heterogeneous group of cardiovascular disorders. In addition, HF power is relatively constant across the range of typical breathing rates. These data indicate that there is no need to control breathing rate to interpret HF power when RR variability (and specifically HF power) is used to identify high-risk cardiac patients.

Association of glucose homeostasis measures with heart rate variability among Hispanic/Latino adults without diabetes: the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

PubMed

Meyer, Michelle L; Gotman, Nathan M; Soliman, Elsayed Z; Whitsel, Eric A; Arens, Raanan; Cai, Jianwen; Daviglus, Martha L; Denes, Pablo; González, Hector M; Moreiras, Juan; Talavera, Gregory A; Heiss, Gerardo

2016-03-16

Reduced heart rate variability (HRV), a measure of cardiac autonomic function, is associated with an increased risk of cardiovascular disease (CVD) and mortality. Glucose homeostasis measures are associated with reduced cardiac autonomic function among those with diabetes, but inconsistent associations have been reported among those without diabetes. This study aimed to examine the association of glucose homeostasis measures with cardiac autonomic function among diverse Hispanic/Latino adults without diabetes. The Hispanic community Health Study/Study of Latinos (HCHS/SOL; 2008-2011) used two-stage area probability sampling of households to enroll 16,415 self-identified Hispanics/Latinos aged 18-74 years from four USA communities. Resting, standard 12-lead electrocardiogram recordings were used to estimate the following ultrashort-term measures of HRV: RR interval (RR), standard deviation of all normal to normal RR (SDNN) and root mean square of successive differences in RR intervals (RMSSD). Multivariable regression analysis was used to estimate associations between glucose homeostasis measures with HRV using data from 11,994 adults without diabetes (mean age 39 years; 52 % women). Higher fasting glucose was associated with lower RR, SDNN, and RMSSD. Fasting insulin and the homeostasis model assessment of insulin resistance was negatively associated with RR, SDNN, and RMSSD, and the association was stronger among men compared with women. RMSSD was, on average, 26 % lower in men with higher fasting insulin and 29 % lower in men with lower insulin resistance; for women, the corresponding estimates were smaller at 4 and 9 %, respectively. Higher glycated hemoglobin was associated with lower RR, SDNN, and RMSSD in those with abdominal adiposity, defined by sex-specific cut-points for waist circumference, after adjusting for demographics and medication use. There were no associations between glycated hemoglobin and HRV measures among those without abdominal adiposity. Impairment in glucose homeostasis was associated with lower HRV in Hispanic/Latino adults without diabetes, most prominently in men and individuals with abdominal adiposity. These results suggest that reduced cardiac autonomic function is associated with metabolic impairments before onset of overt diabetes in certain subgroups, offering clues for the pathophysiologic processes involved as well as opportunity for identification of those at high risk before autonomic control is manifestly impaired.

HRV based health&sport markers using video from the face.

PubMed

Capdevila, Lluis; Moreno, Jordi; Movellan, Javier; Parrado, Eva; Ramos-Castro, Juan

2012-01-01

Heart Rate Variability (HRV) is an indicator of health status in the general population and of adaptation to stress in athletes. In this paper we compare the performance of two systems to measure HRV: (1) A commercial system based on recording the physiological cardiac signal with (2) A computer vision system that uses a standard video images of the face to estimate RR from changes in skin color of the face. We show that the computer vision system performs surprisingly well. It estimates individual RR intervals in a non-invasive manner and with error levels comparable to those achieved by the physiological based system.

Sequential modulation of cardiac autonomic control induced by cardiopulmonary and arterial baroreflex mechanisms

NASA Technical Reports Server (NTRS)

Furlan, R.; Jacob, G.; Palazzolo, L.; Rimoldi, A.; Diedrich, A.; Harris, P. A.; Porta, A.; Malliani, A.; Mosqueda-Garcia, R.; Robertson, D.

2001-01-01

BACKGROUND: Nonhypotensive lower body negative pressure (LBNP) induces a reflex increase in forearm vascular resistance and muscle sympathetic neural discharge without affecting mean heart rate. We tested the hypothesis that a reflex change of the autonomic modulation of heartbeat might arise during low intensity LBNP without changes of mean heart rate. METHODS AND RESULTS: Ten healthy volunteers underwent plasma catecholamine evaluation and a continuous recording of ECG, finger blood pressure, respiratory activity, and central venous pressure (CVP) during increasing levels of LBNP up to -40 mm Hg. Spectrum and cross-spectrum analyses assessed the changes in the spontaneous variability of R-R interval, respiration, systolic arterial pressure (SAP), and CVP and in the gain (alpha(LF)) of arterial baroreflex control of heart rate. Baroreceptor sensitivity was also evaluated by the SAP/R-R spontaneous sequences technique. LBNP began decreasing significantly: CVP at -10, R-R interval at -20, SAP at -40, and the indexes alpha(LF) and baroreceptor sensitivity at -30 and -20 mm Hg, compared with baseline conditions. Plasma norepinephrine increased significantly at -20 mm Hg. The normalized low-frequency component of R-R variability (LF(R-R)) progressively increased and was significantly higher than in the control condition at -15 mm Hg. CONCLUSIONS: Nonhypotensive LBNP elicits a reflex increase of cardiac sympathetic modulation, as evaluated by LF(R-R), which precedes the changes in the hemodynamics and in the indexes of arterial baroreflex control.

Cortisol release, heart rate and heart rate variability, and superficial body temperature, in horses lunged either with hyperflexion of the neck or with an extended head and neck position.

PubMed

Becker-Birck, M; Schmidt, A; Wulf, M; Aurich, J; von der Wense, A; Möstl, E; Berz, R; Aurich, C

2013-04-01

Bringing the head and neck of ridden horses into a position of hyperflexion is widely used in equestrian sports. In our study, the hypothesis was tested that hyperflexion is an acute stressor for horses. Salivary cortisol concentrations, heart rate, heart rate variability (HRV) and superficial body temperature were determined in horses (n = 16) lunged on two subsequent days. The head and neck of the horse was fixed with side reins in a position allowing forward extension on day A and fixed in hyperflexion on day B. The order of treatments alternated between horses. In response to lunging, cortisol concentration increased (day A from 0.73 ± 0.06 to 1.41 ± 0.13 ng/ml, p < 0.001; day B from 0.68 ± 0.07 to 1.38 ± 0.13 ng/ml, p < 0.001) but did not differ between days A and B. Beat-to-beat (RR) interval decreased in response to lunging on both days. HRV variables standard deviation of RR interval (SDRR) and RMSSD (root mean square of successive RR differences) decreased (p < 0.001) but did not differ between days. In the cranial region of the neck, the difference between maximum and minimum temperature was increased in hyperflexion (p < 0.01). In conclusion, physiological parameters do not indicate an acute stress response to hyperflexion of the head alone in horses lunged at moderate speed and not touched with the whip. However, if hyperflexion is combined with active intervention of a rider, a stressful experience for the horse cannot be excluded. © 2012 Blackwell Verlag GmbH.

Heart rate variability in the individual fetus.

PubMed

Van Leeuwen, Peter; Cysarz, Dirk; Edelhäuser, Friedrich; Grönemeyer, Dietrich

2013-11-01

The change in fetal heart rate and its variability (HRV) during the course of gestation has been documented by numerous studies. The overall drop in heart rate and increase in fetal HRV is associated with fetal growth in general and with the increase in neural integration in particular. The increased complexity of the demands on the cardiovascular system leads to more variation in the temporal course of the heart rate. Most studies that document and interpret these changes are based on data acquired in groups of fetuses. The aim of this work was to investigate HRV within single fetuses. We acquired 213 5min fetal magnetocardiograms in 11 fetuses during the second and third trimesters (at least 10 data sets per fetus, median 17). From the magnetocardiograms we determined the fetal RR interval time series and calculated the standard deviation (SDNN), root mean square of successive differences (RMSSD), approximate entropy (ApEn) and temporal asymmetry (Irrev). For each subject and HRV measure, we performed regression analysis with respect to gestational age, alone and in combination with RR interval. The coefficient of determination R(2) was used to estimate goodness-of-fit. The coefficient of quartile dispersion (CQD) was used to compare the regression parameters for each HRV measure. Overall, the HRV measures increased with age and RR interval. The consistency of the HRV measures within the individual fetuses was greater than in the data pooled over all fetuses. The individual R(2) for the model including age and RR interval was best for ApEn (.79, .59-.94; median, 90% CI), followed by RMSSD (.71, .25-.88), SDNN (.55, .18-.90) and Irrev (.16, .01-.39). These values, except for Irrev, were higher than those calculated over all 213 data sets (R(2)=.65, .63, .35, .28, respectively). The slopes of the regressions of each individual's data were most consistent over all subjects for ApEn, followed by RMSSD and SDNN and Irrev. Interindividually, the time domain measures showed discrepancies and the within-fetus courses were more consistent than the course over all fetuses. On the other hand, the course of ApEn during gestation was not only very consistent within each fetus but also very similar between most of subjects. Complexity measures such as ApEn may thus more consistently reflect prenatal developmental factors influencing cardiovascular regulation. Copyright © 2013 Elsevier B.V. All rights reserved.

Tachycardia-dependent augmentation of "notched J waves" in a general patient population without ventricular fibrillation or cardiac arrest: not a repolarization but a depolarization abnormality?

PubMed

Aizawa, Yoshifusa; Sato, Masahito; Kitazawa, Hitoshi; Aizawa, Yoshiyasu; Takatsuki, Seiji; Oda, Eiji; Okabe, Masaaki; Fukuda, Keiichi

2015-02-01

J waves can be observed in individuals of the general population, but electrocardiographic characteristics are poorly understood. The purpose of this study was to examine the J-wave dynamicity in a general patient population. The responses of J waves (>0.1 mV above the isoelectric line in 2 contiguous leads) to varying RR intervals were analyzed. Patients with aborted sudden cardiac death, documented ventricular fibrillation, or a family history of sudden cardiac death were excluded. The J-wave amplitude was measured at baseline, in beats with short RR intervals in conducted atrial premature beats (APBs) or atrial stimulation during the electrophysiology study, and in the beats next to APBs with prolonged RR intervals. Mainly notched J waves were identified in 94 of 701 (24.5%) general patients (13.4%), and APBs were present in 23 of 94 (24.5%) patients. The mean baseline amplitude of J waves was 0.20 ± 0.06 mV at the baseline RR interval of 853 ± 152 ms, 0.25 ± 0.11 mV at the RR interval in the conducted APB of 545 ± 133 ms (P = .0018), and 0.19 ± 0.08 mV at the RR interval of 1146 ± 314 ms (P = .3102). The clinical characteristics were not different between patients with and without tachycardia-dependent augmentation of J waves. Augmentation of J waves was confirmed by the electrophysiology study: 0.28 ± 0.12 mV vs 0.42 ± 0.11 mV at baseline and in the beats of atrial stimulation, respectively (P = .0001). However, no bradycardia-dependent augmentation (>0.05 mV) was observed. Such tachycardia-dependent augmentation can represent depolarization abnormality rather than repolarization abnormality. J waves in a general patient population were augmented at shorter RR intervals, but not at prolonged RR intervals. Mechanistically, conduction delay is most likely responsible for this. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Identification of atrial fibrillation using electrocardiographic RR-interval difference

NASA Astrophysics Data System (ADS)

Eliana, M.; Nuryani, N.

2017-11-01

Automated detection of atrial fibrillation (AF) is an interesting topic. It is an account of very dangerous, not only as a trigger of embolic stroke, but it’s also related to some else chronical disease. In this study, we analyse the presence of AF by determining irregularities of RR-interval. We utilize the interval comparison to measure the degree of irregularities of RR-interval in a defined segment. The series of RR-interval is segmented with the length of 10 of them. In this study, we use interval comparison for the method. We were comparing all of the intervals there each other. Then we put the threshold to define the low difference and high difference (δ). A segment is defined as AF or Normal Sinus by the number of high δ, so we put the tolerance (β) of high δ there. We have used this method to test the 23 patients data from MIT-BIH. Using the approach and the clinical data we find accuracy, sensitivity, and specificity of 84.98%, 91.99%, and 77.85% respectively.

[Evaluation of the principles of distribution of electrocardiographic R-R intervals for elaboration of methods of automated diagnosis of cardiac rhythm disorders].

PubMed

Tsukerman, B M; Finkel'shteĭn, I E

1987-07-01

A statistical analysis of prolonged ECG records has been carried out in patients with various heart rhythm and conductivity disorders. The distribution of absolute R-R duration values and relationships between adjacent intervals have been examined. A two-step algorithm has been constructed that excludes anomalous and "suspicious" intervals from a sample of consecutively recorded R-R intervals, until only the intervals between contractions of veritably sinus origin remain in the sample. The algorithm has been developed into a programme for microcomputer Electronica NC-80. It operates reliably even in cases of complex combined rhythm and conductivity disorders.

Resting and postexercise heart rate variability in professional handball players.

PubMed

Kayacan, Yildirim; Yildiz, Sedat

2016-03-01

The aim of this study was to evaluate heart rate variability (HRV) in professional handball players during rest and following a 5 min mild jogging exercise. For that purpose, electrocardiogram (ECG) of male handball players (N.=12, mean age 25±3.95 years) and sedentary controls (N.=14, mean age 23.5±2.95 years) were recorded for 5 min at rest and just after 5 min of mild jogging. ECGs were recorded and following HRV parameters were calculated: time-domain variables such as heart rate (HR), average normal-to-normal RR intervals, standard deviation of normal-to-normal RR intervals, square root of the mean of the squares of differences between adjacent NN intervals, percentage of differences between adjacent NN intervals that are greater than 50 milliseconds (pNN50), and frequency-domain variables such as very low frequency, low (LF) and high frequency (HF) of the power and LF/HF ratio. Unpaired t-test was used to find out differences among groups while paired t-test was used for comparison of each group for pre- and postjogging HRV. Pearson correlations were carried out to find out the relationships between the parameters. Blood pressures were not different between handball players and sedentary controls but exercise increased systolic blood pressure (P<0.01). HR was increased with exercise (P<0.001) and was slower in handball players (P<0.01). QTc was increased with exercise (P<0.001) and was higher in handball players (P<0.001). Exercise decreased pNN50 values in both groups but LF/HF ratio increased only in sedentary subjects. In conclusion, results of the HRV parameters show that sympathovagal balance does not appear to change in handball players in response to a mild, short-time (5 min) jogging exercise. However, in sedentary subjects, either the sympathetic regulation of the autonomous nervous system increased or vagal withdrawal occurred.

Association between respiratory mechanics and autonomic function in morbid obesity.

PubMed

Sant' Anna, M; Carvalhal, R F; Carneiro, J R I; Lapa, M S; Zin, W A; Lugon, J R; Guimarães, F S

2014-01-01

This study aimed to investigate the association between respiratory mechanics and autonomic modulation in morbidly obese patients. We evaluated 10 morbidly obese subjects (BMI=52.9±11.2kg/m(2)), aged 23-58 years. Assessment of respiratory mechanics was done by the forced oscillation technique (FOT), and cardiovascular autonomic function was recorded by heart rate variability analysis (HRV). The Pearson correlation coefficient was used to test the associations between respiratory mechanics and HRV variables. There were associations between the standard deviation of all RR intervals (SDNN) and airway resistance (Rm) (r=-0.82; p=0.004), SDNN and respiratory system resistance (R0) (r=-0.79; p=0.006), root mean square of successive differences between adjacent normal RR intervals (rMSSD) and respiratory system resistance (R5) (r=-0.643; p=0.0451), rMSSD and R0 (r=-0.64; p=0.047), and rMSSD and Rm (r=-0.658; p=0.039). We concluded that the airway and respiratory system resistances are negatively associated with parasympathetic activity in patients with morbid obesity. Copyright © 2013 Sociedade Portuguesa de Pneumologia. Published by Elsevier España. All rights reserved.

Increasing sensitivity in the measurement of heart rate variability: the method of non-stationary RR time-frequency analysis.

PubMed

Melkonian, D; Korner, A; Meares, R; Bahramali, H

2012-10-01

A novel method of the time-frequency analysis of non-stationary heart rate variability (HRV) is developed which introduces the fragmentary spectrum as a measure that brings together the frequency content, timing and duration of HRV segments. The fragmentary spectrum is calculated by the similar basis function algorithm. This numerical tool of the time to frequency and frequency to time Fourier transformations accepts both uniform and non-uniform sampling intervals, and is applicable to signal segments of arbitrary length. Once the fragmentary spectrum is calculated, the inverse transform recovers the original signal and reveals accuracy of spectral estimates. Numerical experiments show that discontinuities at the boundaries of the succession of inter-beat intervals can cause unacceptable distortions of the spectral estimates. We have developed a measure that we call the "RR deltagram" as a form of the HRV data that minimises spectral errors. The analysis of the experimental HRV data from real-life and controlled breathing conditions suggests transient oscillatory components as functionally meaningful elements of highly complex and irregular patterns of HRV. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

A Prospective Cohort Study of Cigarette Prices and Smoking Cessation in Older Smokers.

PubMed

Stevens, Victoria L; Diver, W Ryan; Stoklosa, Michal; Flanders, W Dana; Westmaas, J Lee; Jemal, Ahmedin; Drope, Jeffrey M; Gapstur, Susan M; Jacobs, Eric J

2017-07-01

Background: Cigarette price increases effectively prevent smoking initiation and reduce cigarette consumption among young smokers. However, the impact of cigarette prices on smoking cessation among older smokers is less clear, particularly for those aged 65 years and older, a group that is at highest risk of smoking-related disease and will almost double in the United States between 2012 and 2050. Methods: Biennial questionnaires administered between 1997 and 2013 assessed smoking status for 9,446 Cancer Prevention Study-II Nutrition Cohort participants who were ≥50 years old and lived in Washington, DC, and 48 states. For each interval between biennial questionnaires, change in price per pack and average price level per pack were calculated. The separate associations between these price variables and smoking cessation during the same time interval were determined. Results: In multivariable-adjusted models, each $1.00 price increase was associated with a 9% higher rate of quitting [rate ratio (RR) = 1.09; 95% confidence interval (CI), 1.04-1.14). Each $1.00 increase in average price was associated with a 6% higher rate of quitting (RR = 1.06; 95% CI, 1.02-1.10). The association with average price was strongest among smokers aged 65 years and older (RR = 1.07; 95% CI, 1.04-1.11) and, for price change, for smokers with no major prevalent disease (RR = 1.13; 95% CI, 1.07-1.19). Conclusions: These results suggest that increasing cigarette prices will promote quitting even among smokers aged 65 years and older. Impact: Increasing cigarette prices through higher taxes could reduce smoking rates among older adults and decrease risk of smoking-related cancers and diseases in this high-risk group. Cancer Epidemiol Biomarkers Prev; 26(7); 1071-7. ©2017 AACR . ©2017 American Association for Cancer Research.

Controlled breathing protocols probe human autonomic cardiovascular rhythms

NASA Technical Reports Server (NTRS)

Cooke, W. H.; Cox, J. F.; Diedrich, A. M.; Taylor, J. A.; Beightol, L. A.; Ames, J. E. 4th; Hoag, J. B.; Seidel, H.; Eckberg, D. L.

1998-01-01

The purpose of this study was to determine how breathing protocols requiring varying degrees of control affect cardiovascular dynamics. We measured inspiratory volume, end-tidal CO2, R-R interval, and arterial pressure spectral power in 10 volunteers who followed the following 5 breathing protocols: 1) uncontrolled breathing for 5 min; 2) stepwise frequency breathing (at 0.3, 0.25, 0.2, 0.15, 0.1, and 0.05 Hz for 2 min each); 3) stepwise frequency breathing as above, but with prescribed tidal volumes; 4) random-frequency breathing (approximately 0.5-0.05 Hz) for 6 min; and 5) fixed-frequency breathing (0.25 Hz) for 5 min. During stepwise breathing, R-R interval and arterial pressure spectral power increased as breathing frequency decreased. Control of inspired volume reduced R-R interval spectral power during 0.1 Hz breathing (P < 0.05). Stepwise and random-breathing protocols yielded comparable coherence and transfer functions between respiration and R-R intervals and systolic pressure and R-R intervals. Random- and fixed-frequency breathing reduced end-tidal CO2 modestly (P < 0.05). Our data suggest that stringent tidal volume control attenuates low-frequency R-R interval oscillations and that fixed- and random-rate breathing may decrease CO2 chemoreceptor stimulation. We conclude that autonomic rhythms measured during different breathing protocols have much in common but that a stepwise protocol without stringent control of inspired volume may allow for the most efficient assessment of short-term respiratory-mediated autonomic oscillations.

Basic cardiovascular variability signals: mutual directed interactions explored in the information domain.

PubMed

Javorka, Michal; Krohova, Jana; Czippelova, Barbora; Turianikova, Zuzana; Lazarova, Zuzana; Javorka, Kamil; Faes, Luca

2017-05-01

The study of short-term cardiovascular interactions is classically performed through the bivariate analysis of the interactions between the beat-to-beat variability of heart period (RR interval from the ECG) and systolic blood pressure (SBP). Recent progress in the development of multivariate time series analysis methods is making it possible to explore how directed interactions between two signals change in the context of networks including other coupled signals. Exploiting these advances, the present study aims at assessing directional cardiovascular interactions among the basic variability signals of RR, SBP and diastolic blood pressure (DBP), using an approach which allows direct comparison between bivariate and multivariate coupling measures. To this end, we compute information-theoretic measures of the strength and delay of causal interactions between RR, SBP and DBP using both bivariate and trivariate (conditioned) formulations in a group of healthy subjects in a resting state and during stress conditions induced by head-up tilt (HUT) and mental arithmetics (MA). We find that bivariate measures better quantify the overall (direct  +  indirect) information transferred between variables, while trivariate measures better reflect the existence and delay of directed interactions. The main physiological results are: (i) the detection during supine rest of strong interactions along the pathway RR  →  DBP  →  SBP, reflecting marked Windkessel and/or Frank-Starling effects; (ii) the finding of relatively weak baroreflex effects SBP  →  RR at rest; (iii) the invariance of cardiovascular interactions during MA, and the emergence of stronger and faster SBP  →  RR interactions, as well as of weaker RR  →  DBP interactions, during HUT. These findings support the importance of investigating cardiovascular interactions from a network perspective, and suggest the usefulness of directed information measures to assess physiological mechanisms and track their changes across different physiological states.

The "Chaos Theory" and nonlinear dynamics in heart rate variability analysis: does it work in short-time series in patients with coronary heart disease?

PubMed

Krstacic, Goran; Krstacic, Antonija; Smalcelj, Anton; Milicic, Davor; Jembrek-Gostovic, Mirjana

2007-04-01

Dynamic analysis techniques may quantify abnormalities in heart rate variability (HRV) based on nonlinear and fractal analysis (chaos theory). The article emphasizes clinical and prognostic significance of dynamic changes in short-time series applied on patients with coronary heart disease (CHD) during the exercise electrocardiograph (ECG) test. The subjects were included in the series after complete cardiovascular diagnostic data. Series of R-R and ST-T intervals were obtained from exercise ECG data after sampling digitally. The range rescaled analysis method determined the fractal dimension of the intervals. To quantify fractal long-range correlation's properties of heart rate variability, the detrended fluctuation analysis technique was used. Approximate entropy (ApEn) was applied to quantify the regularity and complexity of time series, as well as unpredictability of fluctuations in time series. It was found that the short-term fractal scaling exponent (alpha(1)) is significantly lower in patients with CHD (0.93 +/- 0.07 vs 1.09 +/- 0.04; P < 0.001). The patients with CHD had higher fractal dimension in each exercise test program separately, as well as in exercise program at all. ApEn was significant lower in CHD group in both RR and ST-T ECG intervals (P < 0.001). The nonlinear dynamic methods could have clinical and prognostic applicability also in short-time ECG series. Dynamic analysis based on chaos theory during the exercise ECG test point out the multifractal time series in CHD patients who loss normal fractal characteristics and regularity in HRV. Nonlinear analysis technique may complement traditional ECG analysis.

Global longitudinal strain corrected by RR interval is a superior predictor of all-cause mortality in patients with systolic heart failure and atrial fibrillation.

PubMed

Modin, Daniel; Sengeløv, Morten; Jørgensen, Peter Godsk; Bruun, Niels Eske; Olsen, Flemming Javier; Dons, Maria; Fritz Hansen, Thomas; Jensen, Jan Skov; Biering-Sørensen, Tor

2018-04-01

Quantification of systolic function in patients with atrial fibrillation (AF) is challenging. A novel approach, based on RR interval correction, to counteract the varying heart cycle lengths in AF has recently been proposed. Whether this method is superior in patients with systolic heart failure (HFrEF) with AF remains unknown. This study investigates the prognostic value of RR interval-corrected peak global longitudinal strain {GLSc = GLS/[RR^(1/2)]} in relation to all-cause mortality in HFrEF patients displaying AF during echocardiographic examination. Echocardiograms from 151 patients with HFrEF and AF during examination were analysed offline. Peak global longitudinal strain (GLS) was averaged from 18 myocardial segments obtained from three apical views. GLS was indexed with the square root of the RR interval {GLSc = GLS/[RR^(1/2)]}. Endpoint was all-cause mortality. During a median follow-up of 2.7 years, 40 patients (26.5%) died. Neither uncorrected GLS (P = 0.056) nor left ventricular ejection fraction (P = 0.053) was significantly associated with all-cause mortality. After RR^(1/2) indexation, GLSc became a significant predictor of all-cause mortality (hazard ratio 1.16, 95% confidence interval 1.02-1.22, P = 0.014, per %/s^(1/2) decrease). GLSc remained an independent predictor of mortality after multivariable adjustment (age, sex, mean heart rate, mean arterial blood pressure, left atrial volume index, and E/e') (hazard ratio 1.17, 95% confidence interval 1.05-1.31, P = 0.005 per %/s^(1/2) decrease). Decreasing {GLSc = GLS/[RR^(1/2)]}, but not uncorrected GLS nor left ventricular ejection fraction, was significantly associated with increased risk of all-cause mortality in HFrEF patients with AF and remained an independent predictor after multivariable adjustment. © 2017 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.

Depressed heart rate variability as an independent predictor of death in chronic congestive heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

PubMed

Ponikowski, P; Anker, S D; Chua, T P; Szelemej, R; Piepoli, M; Adamopoulos, S; Webb-Peploe, K; Harrington, D; Banasiak, W; Wrabec, K; Coats, A J

1997-06-15

After acute myocardial infarction, depressed heart rate variability (HRV) has been proven to be a powerful independent predictor of a poor outcome. Although patients with chronic congestive heart failure (CHF) have also markedly impaired HRV, the prognostic value of HRV analysis in these patients remains unknown. The aim of this study was to investigate whether HRV parameters could predict survival in 102 consecutive patients with moderate to severe CHF (90 men, mean age 58 years, New York Heart Association [NYHA] class II to IV, CHF due to idiopathic dilated cardiomyopathy in 24 patients and ischemic heart disease in 78 patients, ejection fraction [EF], 26%; peak oxygen consumption, 16.9 ml/kg/min) after exclusion of patients in atrial fibrilation with diabetes or with chronic renal failure. In the prognostic analysis (Cox proportional-hazards model, Kaplan-Meier survival analysis), the following factors were investigated: age, CHF etiology, NYHA class, EF, peak oxygen consumption, presence of ventricular tachycardia on Holter monitoring, and HRV measures derived from 24-hour electrocardiography monitoring, calculated in the time (standard deviation of all normal RR intervals [SDNN], standard deviation of 5-minute RR intervals [SDANN], mean of all 5-minute standard deviations of RR intervals [SD], root-mean-square of difference of successive RR intervals [rMSSD], and percentage of adjacent RR intervals >50 ms different [pNN50]) and frequency domain (total power [TP], power within low-frequency band [LF], and power within high-frequency band [HF]). During follow-up of 584 +/- 405 days (365 days in all who survived), 19 patients (19%) died (mean time to death: 307 +/- 315 days, range 3 to 989). Cox's univariate analysis identified the following factors to be predictors of death: NYHA (p = 0.003), peak oxygen consumption (p = 0.01), EF (p = 0.02), ventricular tachycardia on Holter monitoring (p = 0.05), and among HRV measures: SDNN (p = 0.004), SDANN (p = 0.003), SD (p = 0.02), and LF (p = 0.003). In multivariate analysis, HRV parameters (SDNN, SDANN, LF) were found to predict survival independently of NYHA functional class, EF, peak oxygen consumption, and ventricular tachycardia on Holter monitoring. The Kaplan-Meier survival curves revealed SDNN < 100 ms to be a useful risk factor; 1-year survival in patients with SDNN < 100 ms was 78% when compared with 95% in those with SDNN > 100 ms (p = 0.008). The coexistence of SDNN < 100 ms and a peak oxygen consumption < 14 ml/kg/min allowed identification of a group of 18 patients with a particularly poor prognosis (1-year survival 63% vs 94% in the remaining patients, p <0.001). We conclude that depressed HRV on 24-hour ambulatory electrocardiography monitoring is an independent risk factor for a poor prognosis in patients with CHF. Whether analysis of HRV could be recommended in the risk stratification for better management of patients with CHF needs further investigation.

Association with meteo-climatological factors and daily emergency visits for renal colic and urinary calculi in Cuneo, Italy. A retrospective observational study, 2007-2010

NASA Astrophysics Data System (ADS)

Condemi, Vincenzo; Gestro, Massimo; Dozio, Elena; Tartaglino, Bruno; Corsi Romanelli, Massimiliano Marco; Solimene, Umberto; Meco, Roberto

2015-03-01

The incidence of nephrolithiasis is rising worldwide, especially in women and with increasing age. Incidence and prevalence of kidney stones are affected by genetic, nutritional, and environmental factors. The aim of this study is to investigate the link between various meteorological factors (independent variables) and the daily number of visits to the Emergency Department (ED of the S. Croce and Carle Hospital of Cuneo for renal colic (RC) and urinary stones (UC) as the dependent variable over the years 2007-2010. The Poisson generalized regression models (PGAMs) have been used in different progressive ways. The results of PGAMs (stage 1) adjusted for seasonal and calendar factors confirmed a significant correlation ( p < 0.03) with the thermal parameter. Evaluation of the dose-response effect [PGAMs combined with distributed lags nonlinear models (DLNMs)—stage 2], expressed in terms of relative risk (RR) and cumulative relative risk (RRC), indicated a relative significant effect up to 15 lag days of lag (RR > 1), with a first peak after 5 days (lag ranges 0-1, 0-3, and 0-5) and a second weak peak observed along the 5-15 lag range days. The estimated RR for females was significant, mainly in the second and fourth age group considered (19-44 and >65 years): RR for total ED visits 1.27, confidence interval (CI) 1.11-1.46 (lag 0-5 days); RR 1.42, CI 1.01-2.01 (lag 0-10 days); and RR 1.35, CI 1.09-1.68 (lag 0-15 days). The research also indicated a moderate involvement of the thermal factor in the onset of RC caused by UC, exclusively in the female sex. Further studies will be necessary to confirm these results.

Left Atrial Size and Function in a Canine Model of Chronic Atrial Fibrillation and Heart Failure

PubMed Central

Goldberg, Adam; Kusunose, Kenya; Qamruddin, Salima; Rodriguez, L. Leonardo; Mazgalev, Todor N.; Griffin, Brian P.; Van Wagoner, David R.; Zhang, Youhua; Popović, Zoran B.

2016-01-01

Background Our aim was to assess how atrial fibrillation (AF) induction, chronicity, and RR interval irregularity affect left atrial (LA) function and size in the setting of underlying heart failure (HF), and to determine whether AF effects can be mitigated by vagal nerve stimulation (VNS). Methods HF was induced by 4-weeks of rapid ventricular pacing in 24 dogs. Subsequently, AF was induced and maintained by atrial pacing at 600 bpm. Dogs were randomized into control (n = 9) and VNS (n = 15) groups. In the VNS group, atrioventricular node fat pad stimulation (310 μs, 20 Hz, 3–7 mA) was delivered continuously for 6 months. LA volume and LA strain data were calculated from bi-weekly echocardiograms. Results RR intervals decreased with HF in both groups (p = 0.001), and decreased further during AF in control group (p = 0.014), with a non-significant increase in the VNS group during AF. LA size increased with HF (p<0.0001), with no additional increase during AF. LA strain decreased with HF (p = 0.025) and further decreased after induction of AF (p = 0.0001). LA strain decreased less (p = 0.001) in the VNS than in the control group. Beat-by-beat analysis showed a curvilinear increase of LA strain with longer preceding RR interval, (r = 0.45, p <0.0001) with LA strain 1.1% higher (p = 0.02) in the VNS-treated animals, independent of preceding RR interval duration. The curvilinear relationship between ratio of preceding and pre-preceding RR intervals, and subsequent LA strain was weaker, (r = 0.28, p = 0.001). However, VNS-treated animals again had higher LA strain (by 2.2%, p = 0.002) independently of the ratio of preceding and pre-preceding RR intervals. Conclusions In the underlying presence of pacing-induced HF, AF decreased LA strain, with little impact on LA size. LA strain depends on the preceding RR interval duration. PMID:26771573

Combinatorial effect of nicotine and black tea on heart rate variability: Useful or harmful?

PubMed

Joukar, S; Sheibani, M

2017-06-01

The effect of nicotine on heart rate variability (HRV) is controversial. Autonomic nervous system is the main regulator of heart rhythm, and heart rate variability is an appropriate index to assessment of the effects of the autonomic system on heart. In this study, the combination effect of nicotine and black tea consumption on sympatho-vagal balance and heart rate variability was investigated in rats. Male Wistar rats were randomized into four groups as control, tea (2.5 g/100 cc, daily), nicotine (2 mg/kg/d) and tea plus nicotine groups which treated for 28 days, and in the 29th day, their electrocardiograms (lead II) were recorded. The mean of high-frequency power (HF) in tea, nicotine and tea plus nicotine groups was significantly more than control group (P < .05), and low-frequency power/high-frequency power (LF/HF) ratio in the nicotine and tea + nicotine groups was significantly less than control group (P < .05). LF values did not differ significantly among groups. Mean of standard deviation of normal RR intervals (SDNN) and square root of the mean squared differences of successive RR intervals (RMSSD) increased significantly in tea, nicotine and tea + nicotine groups in comparison with control group (P < .05) Overall, 4-week administration of black tea, nicotine or their combination with dosages used in this study can increase the heart rate variability and improve the sympatho-vagal balance in rat. © 2017 John Wiley & Sons Ltd.

Responses of heart rate and blood pressure to KC-135 hyper-gravity

NASA Technical Reports Server (NTRS)

Satake, Hirotaka; Matsunami, Ken'ichi; Reschke, Millard F.

1992-01-01

Many investigators have clarified the effects of hyper gravitational-inertial forces (G) upon the cardiovascular system, using the centrifugal apparatus with short rotating radius. We investigated the cardiovascular responses to KC-135 hyper-G flight with negligibly small angular velocity. Six normal, healthy subjects 29 to 40 years old (5 males and 1 female) took part in this experiment. Hyper gravitational-inertial force was generated by the KC-135 hyper-G flight, flown in a spiral path with a very long radius of 1.5 miles. Hyper-G was sustained for 3 minutes with 1.8 +Gz in each session and was repeatedly exposed to very subject sitting on a chair 5 times. The preliminary results of blood pressure and R-R interval are discussed. An exposure of 1.8 +Gz stress resulted in a remarkable increase of systolic and diastolic blood pressure, while the pulse pressure did not change and remained equal to the control level regardless of an exposure of hyper-G. These results in blood pressure indicate an increase of resistance in the peripheral vessels, when an exposure of hyper-G was applied. The R-R interval was calculated from ECG. R-R interval in all subjects was changed but not systematically, and R-R interval became obviously shorter during the hyper-G period than during the 1 +Gz control period although R-R interval varied widely in some cases. The coefficient of variation of R-R interval was estimated to determine the autonomic nerve activity, but no significant change was detectable.

Reproducibility of Heart Rate Variability Is Parameter and Sleep Stage Dependent.

PubMed

Herzig, David; Eser, Prisca; Omlin, Ximena; Riener, Robert; Wilhelm, Matthias; Achermann, Peter

2017-01-01

Objective: Measurements of heart rate variability (HRV) during sleep have become increasingly popular as sleep could provide an optimal state for HRV assessments. While sleep stages have been reported to affect HRV, the effect of sleep stages on the variance of HRV parameters were hardly investigated. We aimed to assess the variance of HRV parameters during the different sleep stages. Further, we tested the accuracy of an algorithm using HRV to identify a 5-min segment within an episode of slow wave sleep (SWS, deep sleep). Methods: Polysomnographic (PSG) sleep recordings of 3 nights of 15 healthy young males were analyzed. Sleep was scored according to conventional criteria. HRV parameters of consecutive 5-min segments were analyzed within the different sleep stages. The total variance of HRV parameters was partitioned into between-subjects variance, between-nights variance, and between-segments variance and compared between the different sleep stages. Intra-class correlation coefficients of all HRV parameters were calculated for all sleep stages. To identify an SWS segment based on HRV, Pearson correlation coefficients of consecutive R-R intervals (rRR) of moving 5-min windows (20-s steps). The linear trend was removed from the rRR time series and the first segment with rRR values 0.1 units below the mean rRR for at least 10 min was identified. A 5-min segment was placed in the middle of such an identified segment and the corresponding sleep stage was used to assess the accuracy of the algorithm. Results: Good reproducibility within and across nights was found for heart rate in all sleep stages and for high frequency (HF) power in SWS. Reproducibility of low frequency (LF) power and of LF/HF was poor in all sleep stages. Of all the 5-min segments selected based on HRV data, 87% were accurately located within SWS. Conclusions: SWS, a stable state that, in contrast to waking, is unaffected by internal and external factors, is a reproducible state that allows reliable determination of heart rate, and HF power, and can satisfactorily be detected based on R-R intervals, without the need of full PSG. Sleep may not be an optimal condition to assess LF power and LF/HF power ratio.

Reproducibility of Heart Rate Variability Is Parameter and Sleep Stage Dependent

PubMed Central

Herzig, David; Eser, Prisca; Omlin, Ximena; Riener, Robert; Wilhelm, Matthias; Achermann, Peter

2018-01-01

Objective: Measurements of heart rate variability (HRV) during sleep have become increasingly popular as sleep could provide an optimal state for HRV assessments. While sleep stages have been reported to affect HRV, the effect of sleep stages on the variance of HRV parameters were hardly investigated. We aimed to assess the variance of HRV parameters during the different sleep stages. Further, we tested the accuracy of an algorithm using HRV to identify a 5-min segment within an episode of slow wave sleep (SWS, deep sleep). Methods: Polysomnographic (PSG) sleep recordings of 3 nights of 15 healthy young males were analyzed. Sleep was scored according to conventional criteria. HRV parameters of consecutive 5-min segments were analyzed within the different sleep stages. The total variance of HRV parameters was partitioned into between-subjects variance, between-nights variance, and between-segments variance and compared between the different sleep stages. Intra-class correlation coefficients of all HRV parameters were calculated for all sleep stages. To identify an SWS segment based on HRV, Pearson correlation coefficients of consecutive R-R intervals (rRR) of moving 5-min windows (20-s steps). The linear trend was removed from the rRR time series and the first segment with rRR values 0.1 units below the mean rRR for at least 10 min was identified. A 5-min segment was placed in the middle of such an identified segment and the corresponding sleep stage was used to assess the accuracy of the algorithm. Results: Good reproducibility within and across nights was found for heart rate in all sleep stages and for high frequency (HF) power in SWS. Reproducibility of low frequency (LF) power and of LF/HF was poor in all sleep stages. Of all the 5-min segments selected based on HRV data, 87% were accurately located within SWS. Conclusions: SWS, a stable state that, in contrast to waking, is unaffected by internal and external factors, is a reproducible state that allows reliable determination of heart rate, and HF power, and can satisfactorily be detected based on R-R intervals, without the need of full PSG. Sleep may not be an optimal condition to assess LF power and LF/HF power ratio. PMID:29367845

Behavioral neurocardiac training in hypertension: a randomized, controlled trial.

PubMed

Nolan, Robert P; Floras, John S; Harvey, Paula J; Kamath, Markad V; Picton, Peter E; Chessex, Caroline; Hiscock, Natalie; Powell, Jonathan; Catt, Michael; Hendrickx, Hilde; Talbot, Duncan; Chen, Maggie H

2010-04-01

It is not established whether behavioral interventions add benefit to pharmacological therapy for hypertension. We hypothesized that behavioral neurocardiac training (BNT) with heart rate variability biofeedback would reduce blood pressure further by modifying vagal heart rate modulation during reactivity and recovery from standardized cognitive tasks ("mental stress"). This randomized, controlled trial enrolled 65 patients with uncomplicated hypertension to BNT or active control (autogenic relaxation), with six 1-hour sessions over 2 months with home practice. Outcomes were analyzed with linear mixed models that adjusted for antihypertensive drugs. BNT reduced daytime and 24-hour systolic blood pressures (-2.4+/-0.9 mm Hg, P=0.009, and -2.1+/-0.9 mm Hg, P=0.03, respectively) and pulse pressures (-1.7+/-0.6 mm Hg, P=0.004, and -1.4+/-0.6 mm Hg, P=0.02, respectively). No effect was observed for controls (P>0.10 for all indices). BNT also increased RR-high-frequency power (0.15 to 0.40 Hz; P=0.01) and RR interval (P<0.001) during cognitive tasks. Among controls, high-frequency power was unchanged (P=0.29), and RR interval decreased (P=0.03). Neither intervention altered spontaneous baroreflex sensitivity (P>0.10). In contrast to relaxation therapy, BNT with heart rate variability biofeedback modestly lowers ambulatory blood pressure during wakefulness, and it augments tonic vagal heart rate modulation. It is unknown whether efficacy of this treatment can be improved with biofeedback of baroreflex gain. BNT, alone or as an adjunct to drug therapy, may represent a promising new intervention for hypertension.

Oxytocin's role on the cardiorespiratory activity of endotoxemic rats.

PubMed

Elorza-Ávila, Ana Rosa; Reyes-Lagos, José Javier; Hadamitzky, Martin; Peña-Castillo, Miguel Ángel; Echeverría, Juan Carlos; Ortiz-Pedroza, María Del Rocío; Lückemann, Laura; Schedlowski, Manfred; Pacheco-López, Gustavo

2017-02-01

Recent findings concerning oxytocin indicate its anti-inflammatory, cardioprotective and parasympathetic modulating properties. In this study, we investigated the effects of systemically applied oxytocin on the cardiorespiratory activity in a rodent model of moderate endotoxemia. Telemetrically recorded electrocardiogram (ECGs) from animals which received lipopolysaccharide (LPS); oxytocin (Ox); lipopolysaccharide+oxytocin (LPS+Ox), or vehicle (V) were analyzed using the ECG-derived respiration (EDR) technique to estimate the respiratory rate. The mean R-R interval and the spectral parameters of heart rate variability (HRV), such as the natural logarithm of the high frequency (lnHF) and low frequency (lnLF) components were also estimated up to 24h after treatment. The endotoxemic animals (LPS) showed an elevated respiratory rate as well as a reduced mean R-R interval, lnHF and lnLF components compared to controls (V) from +5 to +12h after the treatment. The administration of oxytocin significantly attenuated the hyperventilation produced by the LPS-induced endotoxemia (LPS+Ox) and restored the values of the mean R-R interval and such spectral parameters at different time points. Our results support the existence of a link among the respiratory, cardiovascular, and immune systems in which oxytocin seems to act as a potential cardioprotective peptide by favoring cardiac cholinergic autonomic coupling. As a result, oxytocin diminished animal's endotoxemic tachypnea and restored the cardiorespiratory interactions, which was indicated by the spectral components of HRV. Copyright © 2016 Elsevier B.V. All rights reserved.

Psychophysiological correlates of relaxation induced by standard autogenic training.

PubMed

Mishima, N; Kubota, S; Nagata, S

1999-01-01

The present study aimed to determine the psychophysiological changes induced in subjects by standard autogenic training (AT). Physiological measurements were taken under strict experimental conditions. Thirty-one healthy students were divided randomly into two groups: the AT group and the control group. In the first session, the physiological variables were measured for all students before and after all were asked to relax in their own way. The AT group were then taught AT for 3 months, after which time the measurements were repeated. In the second session, the AT group practised the standard AT exercise, while the control group repeated their own form of simple relaxation. Electrocardiogram, plethysmogram (PTG) and blood pressure (BP) were measured while the students carried out a breathing rate of 15 cycles/min. The R-R intervals and BP were analysed by an autoregressive model for spectral analysis, and the data were compared by repeated-measures ANOVA. The AT group had a significant increase in the mean R-R interval and a significant decrease in the baseline deflection of the PTG in the second session. There were no significant changes in sympathetic activity except for the change in the PTG, although low frequency amplitude of systolic BP decreased slightly. AT was found to induce significant changes that were independent of respiration in healthy students, although paced breathing might have operated as a mental stress. The increase in mean R-R interval and the decrease in baseline deflection of the PTG were the most robust correlates of AT.

Diagnostic delays in 537 symptomatic cases of Middle East respiratory syndrome coronavirus infection in Saudi Arabia.

PubMed

Ahmed, Anwar E

2017-09-01

Although the literature indicates that patient delays in seeking medical support for Middle East respiratory syndrome coronavirus (MERS-CoV) infections are associated with poor clinical outcomes, delays in the diagnosis itself remain poorly understood in these patients. This study aimed to determine the median time interval from symptom onset to a confirmed diagnosis and to identify the potential predictors of this interval in Saudi Arabian MERS patients. This was a retrospective study of patients with confirmed MERS who were publicly reported by the World Health Organization (WHO). Five hundred and thirty-seven symptomatic cases of MERS-CoV infection were included. The median time interval between symptom onset and confirmation of the MERS diagnosis was 4 days (interquartile range 2-7 days), ranging from 0 to 36 days. According to the negative binomial model, the unadjusted rate ratio (RR) of delays in the diagnosis was significantly higher in older patients (>65 years) (RR 1.42), non-healthcare workers (RR 1.74), patients with severe illness (RR 1.22), those with an unknown source of infection (RR 1.84), and those who had been in close contact with camels (RR 1.74). After accounting for confounders, the adjusted rate ratio (aRR) of delays in the diagnosis was independently associated with unknown source of infection (aRR 1.68) and close contact with camels (aRR 1.58). The time interval from symptom onset to diagnosis was greater in older patients, non-healthcare workers, patients with severe illness, patients with an unknown source of infection, and patients who had been in close contact with camels. The findings warrant educational interventions to raise general public awareness of the importance of early symptom notification. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Cardiac electrical conduction, autonomic activity and biomarker release during recovery from prolonged strenuous exercise in trained male cyclists.

PubMed

Stewart, Glenn M; Kavanagh, Justin J; Koerbin, Gus; Simmonds, Michael J; Sabapathy, Surendran

2014-01-01

Although markers of myocyte injury, electrolyte disturbances and an autonomic imbalance have been reported following exercise, the effect of prolonged strenuous activity on cardiac electrical conduction is not well understood. This study examined atrial and ventricular conduction dynamics during recovery from exercise. Electrocardiographic intervals were obtained from eight highly-trained males before, during recovery (15, 30, 45 and 60 min post-exercise) and 24 h after a prolonged bout of strenuous exercise. Time-domain, frequency-domain and non-linear analyses of the RR, PR and QT intervals were analysed to investigate the effect of exercise on autonomic modulation and cardiac electrical conduction. Serum electrolyte and high-sensitivity cardiac troponin T (hs-cTnT) concentrations were measured before exercise, and after 60 min and 24 h of recovery. The root mean square of the successive differences of RR, PR and QT intervals was significantly reduced during recovery (p < 0.05). Normalised low- and high-frequency power of RR intervals significantly increased and decreased, respectively, during recovery. Approximate entropy of PR and QT intervals, and the QT-variability index significantly increased during recovery. All measures except mean QT interval (pre 422 ± 10 ms vs 24 h post 442 ± 11 ms, p = 0.013) returned to pre-exercise values after 24 h. Serum hs-cTnT was significantly elevated 60 min after exercise (pre 5.2 ± 0.7 ng L(-1) vs 60 min post 27.4 ± 6.2 ng L(-1), p = 0.01) and correlated with exercising heart rate (R(2) = 0.89, p < 0.001). Serum electrolyte concentrations were unchanged (p > 0.05). The results suggest suppressed parasympathetic and/or sustained sympathetic modulation of heart rate during recovery, concomitant with perturbations in atrial and ventricular conduction dynamics. Exercise-induced hs-cTnT release was heart rate dependent.

Multiresolution Wavelet Analysis of Heartbeat Intervals Discriminates Healthy Patients from Those with Cardiac Pathology

NASA Astrophysics Data System (ADS)

Thurner, Stefan; Feurstein, Markus C.; Teich, Malvin C.

1998-02-01

We applied multiresolution wavelet analysis to the sequence of times between human heartbeats ( R-R intervals) and have found a scale window, between 16 and 32 heartbeat intervals, over which the widths of the R-R wavelet coefficients fall into disjoint sets for normal and heart-failure patients. This has enabled us to correctly classify every patient in a standard data set as belonging either to the heart-failure or normal group with 100% accuracy, thereby providing a clinically significant measure of the presence of heart failure from the R-R intervals alone. Comparison is made with previous approaches, which have provided only statistically significant measures.

Fluctuations in heart rate variability of health care workers during four consecutive extended work shifts and recovery during rest and sleep.

PubMed

Goffeng, Elisabeth M; Nordby, Karl-Christian; Tarvainen, Mika P; Järvelin-Pasanen, Susanna; Wagstaff, Anthony; Goffeng, Lars Ole; Bugge, Merete; Skare, Øivind; Sigstad Lie, Jenny-Anne

2018-04-07

The aim of this study was to investigate fluctuations in heart rate variability (HRV), which reflect autonomic nervous system (ANS) function and potential psychological and physical strain, among 24 health care workers during work and sleep during four consecutive extended work shifts. Data included 24/36/12 h of HRV measurements, two logbooks, and a questionnaire. A cross-shift/cross-week design was applied. HRV was measured during work, leisure time, and sleep. The HRV data included time-domain [mean RR, SD of normal to normal R-R intervals (SDNN), and root mean square of the successive differences (RMSSD)] and frequency-domain [low frequency (LF)/high frequency (HF) ratio] parameters. HRV parameters revealed significant differences among work, leisure time, and sleep. Mean RR, RMSSD, and SDNN values were lower and the LF/HF ratio was higher on the first versus last day of the work period; however, the differences were most prominent in the morning hours. The results indicate higher levels of cardiovascular stress on the first versus fourth day of the working period, and measurements at night indicate a satisfactory recovery from the extended shifts.

Breathing frequency-independent effect of Tai Chi Chuan on autonomic modulation.

PubMed

Lu, Wan-An; Kuo, Cheng-Deng

2014-04-01

This study investigates the breathing frequency (BF)-independent effect of Tai Chi Chuan (TCC) on autonomic nervous modulation in TCC practitioners. Twenty-five TCC practitioners and 25 sedentary normal controls were recruited. The stationary heart rate variability (HRV) measures of TCC practitioners and controls were compared. The same HRV measures in TCC practitioners and among the controls, TCC practitioners before TCC and TCC practitioners 30 min after TCC were compared. In TCC practitioners, the BF, normalized high-frequency power (nHFP), and normalized very low-frequency power were significantly increased, while the normalized low-frequency power (nLFP) was significantly decreased 30 min after TCC. The BF correlated significantly and negatively with heart rate (HR), nHFP and nLFP, and correlated significantly and positively with mean RR interval (MnRR) before TCC in TCC practitioners. A slower BF is associated with a higher HR, a greater vagal modulation, and a greater combined sympatho-vagal modulation before TCC. To remove the effect of BF on HRV measures, new indices such as HR*BF, nHFP*BF, nLFP*BF, and MnRR/BF were introduced for comparison among the controls, TCC practitioners before TCC, and TCC practitioners 30 min after TCC. Thirty minutes after TCC, the MnRR/BF of TCC practitioner was smaller whereas HR*BF and nHFP*BF were greater than those before TCC. The BF-independent effects of TCC on the autonomic nervous modulation of TCC practitioners are an increase in vagal modulation and HR, and a decrease in mean RR interval. The mechanism underlying the parallel increase in HR and vagal modulation in TCC practitioners is not understood yet at present.

Documenting Penicillin Allergy: The Impact of Inconsistency.

PubMed

Shah, Nirav S; Ridgway, Jessica P; Pettit, Natasha; Fahrenbach, John; Robicsek, Ari

2016-01-01

Allergy documentation is frequently inconsistent and incomplete. The impact of this variability on subsequent treatment is not well described. To determine how allergy documentation affects subsequent antibiotic choice. Retrospective, cohort study. 232,616 adult patients seen by 199 primary care providers (PCPs) between January 1, 2009 and January 1, 2014 at an academic medical system. Inter-physician variation in beta-lactam allergy documentation; antibiotic treatment following beta-lactam allergy documentation. 15.6% of patients had a reported beta-lactam allergy. Of those patients, 39.8% had a specific allergen identified and 22.7% had allergic reaction characteristics documented. Variation between PCPs was greater than would be expected by chance (all p<0.001) in the percentage of their patients with a documented beta-lactam allergy (7.9% to 24.8%), identification of a specific allergen (e.g. amoxicillin as opposed to "penicillins") (24.0% to 58.2%) and documentation of the reaction characteristics (5.4% to 51.9%). After beta-lactam allergy documentation, patients were less likely to receive penicillins (Relative Risk [RR] 0.16 [95% Confidence Interval: 0.15-0.17]) and cephalosporins (RR 0.28 [95% CI 0.27-0.30]) and more likely to receive fluoroquinolones (RR 1.5 [95% CI 1.5-1.6]), clindamycin (RR 3.8 [95% CI 3.6-4.0]) and vancomycin (RR 5.0 [95% CI 4.3-5.8]). Among patients with beta-lactam allergy, rechallenge was more likely when a specific allergen was identified (RR 1.6 [95% CI 1.5-1.8]) and when reaction characteristics were documented (RR 2.0 [95% CI 1.8-2.2]). Provider documentation of beta-lactam allergy is highly variable, and details of the allergy are infrequently documented. Classification of a patient as beta-lactam allergic and incomplete documentation regarding the details of the allergy lead to beta-lactam avoidance and use of other antimicrobial agents, behaviors that may adversely impact care quality and cost.

The recursive combination filter approach of pre-processing for the estimation of standard deviation of RR series.

PubMed

Mishra, Alok; Swati, D

2015-09-01

Variation in the interval between the R-R peaks of the electrocardiogram represents the modulation of the cardiac oscillations by the autonomic nervous system. This variation is contaminated by anomalous signals called ectopic beats, artefacts or noise which mask the true behaviour of heart rate variability. In this paper, we have proposed a combination filter of recursive impulse rejection filter and recursive 20% filter, with recursive application and preference of replacement over removal of abnormal beats to improve the pre-processing of the inter-beat intervals. We have tested this novel recursive combinational method with median method replacement to estimate the standard deviation of normal to normal (SDNN) beat intervals of congestive heart failure (CHF) and normal sinus rhythm subjects. This work discusses the improvement in pre-processing over single use of impulse rejection filter and removal of abnormal beats for heart rate variability for the estimation of SDNN and Poncaré plot descriptors (SD1, SD2, and SD1/SD2) in detail. We have found the 22 ms value of SDNN and 36 ms value of SD2 descriptor of Poincaré plot as clinical indicators in discriminating the normal cases from CHF cases. The pre-processing is also useful in calculation of Lyapunov exponent which is a nonlinear index as Lyapunov exponents calculated after proposed pre-processing modified in a way that it start following the notion of less complex behaviour of diseased states.

Changes in Physiologic Parameters and Effects of Hooding in Red-tailed Hawks ( Buteo jamaicensis ) During Manual Restraint.

PubMed

Doss, Grayson A; Mans, Christoph

2016-06-01

Manual restraint in birds of prey is required for many veterinary and research procedures. To investigate the effects of handling stress on physiologic parameters in raptorial birds, 8 red-tailed hawks ( Buteo jamaicensis ) were manually restrained over a 15-minute period. Respiratory rate (RR), heart rate (HR), and cloacal temperature were monitored over time and recorded at defined intervals during the experiment. The effect of hooding on physiologic variables was also evaluated in a complete crossover design. Both RR and HR decreased significantly during the 15-minute restraint period (HR, -80 ± 101.4 beats/min [bpm], [P < .01]; RR, -17.5 ± 22.6 breaths/min, [P < .05]). Hooded birds had significantly lower HRs and RRs at 15 minutes of restraint (HR: 232.5 ± 26 bpm, [P < .037]; RR: 33.1 ± 6.7 breaths/min, [P < .05]) compared to birds restrained without a hood (HR: 280 ± 74.1 bpm; RR: 51.5 ± 28.8 breaths/min). Cloacal temperature increased significantly in all manually restrained birds (+2.2 ± 0.7°C, [P < .01]), with a comparable increase in hooded and nonhooded birds. In this study of the effects of manual restraint on red-tailed hawks, hooding versus nonhooding amplified the decrease in HR and RR but had no effect on stress-induced hyperthermia.

The impact of harm reduction programs and police interventions on the number of syringes collected from public spaces. A time series analysis in Barcelona, 2004-2014.

PubMed

Espelt, A; Villalbí, J R; Bosque-Prous, M; Parés-Badell, O; Mari-Dell'Olmo, M; Brugal, M T

2017-12-01

To estimate the effect of opening two services for people who use drugs and three police interventions on the number of discarded syringes collected from public spaces in Barcelona between 2004 and 2014. We conducted an interrupted time-series analysis of the monthly number of syringes collected from public spaces during this period. The dependent variable was the number of syringes collected per month. The main independent variables were month and five dummy variables (the opening of two facilities with safe consumption rooms, and three police interventions). To examine which interventions affected the number of syringes collected, we performed an interrupted time-series analysis using a quasi-Poisson regression model, obtaining relative risks (RR) and 95% confidence intervals (CIs). The number of syringes collected per month in Barcelona decreased from 13,800 in 2004 to 1655 in 2014 after several interventions. For example, following the closure of an open drug scene in District A of the city, we observed a decreasing trend in the number of syringes collected [RR=0.88 (95% CI: 0.82-0.95)], but an increasing trend in the remaining districts [RR=1.11 (95% CI: 1.05-1.17) and 1.08 (95% CI: 0.99-1.18) for districts B and C, respectively]. Following the opening of a harm reduction facility in District C, we observed an initial increase in the number collected in this district [RR=2.72 (95% CI: 1.57-4.71)] and stabilization of the trend thereafter [RR=0.97 (95% CI: 0.91-1.03)]. The overall number of discarded syringes collected from public spaces has decreased consistently in parallel with a combination of police interventions and the opening of harm reduction facilities. Copyright © 2017 Elsevier B.V. All rights reserved.

Frequency-dependent baroreflex control of blood pressure and heart rate during physical exercise.

PubMed

Spadacini, Giammario; Passino, Claudio; Leuzzi, Stefano; Valle, Felice; Piepoli, Massimo; Calciati, Alessandro; Sleight, Peter; Bernardi, Luciano

2006-02-15

It is widely recognised that during exercise vagal heart rate control is markedly impaired but blood pressure control may or may not be retained. We hypothesised that this uncertainty arose from the differing responses of the vagus (fast) and sympathetic (slow) arms of the autonomic effectors, and to differing sympatho-vagal balance at different exercise intensities. We studied 12 normals at rest, during moderate (50% maximal heart rate) and submaximal (80% maximal heart rate) exercise. The carotid baroreceptors were stimulated by sinusoidal neck suction at the frequency of the spontaneous high- (during moderate exercise) and low-frequency (during submaximal) fluctuations in heart period and blood pressure. The increases in these oscillations induced by neck suction were measured by autoregressive spectral analysis. At rest neck stimulation increased variability at low frequency (RR: from 6.99+/-0.24 to 8.87+/-0.18 ln-ms2; systolic pressure: from 3.05+/-1.7 to 4.09+/-0.17 ln-mm Hg2) and high frequency (RR: from 4.67+/-0.25 to 6.79+/-0.31 ln-ms2; systolic pressure: from 1.93+/-0.2 to 2.67+/-0.125 ln-mm Hg2) (all p<0.001). During submaximal exercise RR variability decreased but systolic pressure variability rose (p<0.01 vs rest); during submaximal exercise low-frequency neck stimulation increased the low-frequency fluctuations in blood pressure (2.35+/-0.51 to 4.25+/-0.38 ln-mm Hg2, p<0.05) and RR. Conversely, neck suction at high frequency was ineffective on systolic pressure, and had only minor effects on RR interval during moderate exercise. During exercise baroreflex control is active on blood pressure, but the efferent response on blood pressure and heart rate is only detected during low frequency stimulation, indicating a frequency-dependent effect.

Changes in autonomic activity preceding onset of nonsustained ventricular tachycardia

NASA Technical Reports Server (NTRS)

Osaka, M.; Saitoh, H.; Sasabe, N.; Atarashi, H.; Katoh, T.; Hayakawa, H.; Cohen, R. J.

1996-01-01

Background: The triggering role of the autonomic nervous system in the initiation of ventricular tachycardia has not been established. To investigate the relationship between changes in autonomic activity and the occurrence of nonsustained ventricular tachycardia (NSVT) we examined heart rate variability (HRV) during the 2-hour period preceding spontaneous episodes of NSVT. Twenty-four subjects were identified retrospectively as having had one episode of NSVT during 24-hour Holter ECC recording. Methods: We measured the mean interval between normal heats (meanRR), the standard deviation of the intervals between beats (SD), the percentage of counts of sequential intervals between normal beats with a change of >50 ms (%RR50), the logarithms of low- and high-frequency spectral components (lnLF, lnHF) of HRV for sequential 10-minute segments preceding NSVT. The correlation dimension (CDim) of HRV was calculated similarly for sequential 20-minute segments. We assessed the significance of the time-course change of each marker over the 120-minute period prior to NSVT onset. Results: MeanRR (P < 0.05), lnLF (P < 0.0001), lnHF (P < 0.0001), the natural logarithm of the ratio of LF to HF (ln[LF/HF]; P < 0.05), and CDim (P < 0.05) showed significant time-course changes during that period, while SD and %RR50 did not. MeanRR, lnLF, lnHF, and CDim all decreased prior to the onset of NSVT, whereas ln(LF/HF) increased. We divided the subjects into two groups: one consisting of 12 patients with coronary artery disease; and the second group of 12 patients without known coronary artery disease. Both groups showed significant changes (P < 0.05) of CDim, lnLF, and lnHF preceding the episodes of NSVT. Conclusions: Changes in the pattern of HRV prior to the onset of episodes of NSVT suggest that changes in autonomic activity may commonly play a role in the triggering of spontaneous episodes of NSVT in susceptible patients. The measured changes suggest a reduction in parasympathetic activity, perhaps in conjunction with an increase in sympathetic activity, may trigger NSVT.

Methoxyflurane anesthesia augments the chronotropic and dromotropic effects of verapamil.

PubMed

Jamali, F; Mayo, P R

1999-01-01

Inhalation anesthetics have been shown to have electrical suppressant effects on excitable membranes such as the cardiac conduction system. Therefore, the anesthetized patient or laboratory animal may respond differently to cardiac drugs when compared with their conscious counterparts. The purpose of this study was to assess the effects of anesthesia with methoxyflurane (MF) on the dromotropic and chronotropic effects of verapamil (VER) in the rat. A lead I ECG was measured using subcutaneous electrodes placed both axilli and over the xyphoid process in male Sprague-Dawley rats. Dromotropic effect was measured using the PR-interval which indicated the electrical spread across the atria to the AV-node and chronotropic effects were determined using RR-interval. A total of six animals were randomized to receive 10 mg/kg s.c. of verapamil in the presence or absence of general anesthesia containing methoxyflurane. In addition, PR-interval and RR-intervals were determined in the presence of only methoxyflurane and at rest without any drug exposure. The time for the ECG to normalize after exposure to methoxyflurane and/or verapamil was also determined. Exposure to verapamil alone resulted in a 5% prolongation in PR-interval and 6% prolongation in RR-interval. Methoxyflurane alone had a larger effect than verapamil demonstrating a 14.5% prolongation in PR-interval and a 12.3% in RR-interval which was statistically significant. The combination of MF + VER resulted in a synergistic prolongation in PR-interval to 28. 7% while the effect on RR-interval was additive with an increase to 17.6%. The time for the ECG to normalize after exposure to VER, MF and VER + MF was 37.5 15.1 min, 69.8 5.3 min, and 148.5 +/- 6.6 min respectively. General anesthesia with MF enhances the dromotropic and chronotropic effect of VER. This should be considered when MF-anesthesia is used in experimental procedure.

Intraday and Interday Reliability of Ultra-Short-Term Heart Rate Variability in Rugby Union Players.

PubMed

Nakamura, Fábio Y; Pereira, Lucas A; Esco, Michael R; Flatt, Andrew A; Moraes, José E; Cal Abad, Cesar C; Loturco, Irineu

2017-02-01

Nakamura, FY, Pereira, LA, Esco, MR, Flatt, AA, Moraes, JE, Cal Abad, CC, and Loturco, I. Intraday and interday reliability of ultra-short-term heart rate variability in rugby union players. J Strength Cond Res 31(2): 548-551, 2017-The aim of this study was to examine the intraday and interday reliability of ultra-short-term vagal-related heart rate variability (HRV) in elite rugby union players. Forty players from the Brazilian National Rugby Team volunteered to participate in this study. The natural log of the root mean square of successive RR interval differences (lnRMSSD) assessments were performed on 4 different days. The HRV was assessed twice (intraday reliability) on the first day and once per day on the following 3 days (interday reliability). The RR interval recordings were obtained from 2-minute recordings using a portable heart rate monitor. The relative reliability of intraday and interday lnRMSSD measures was analyzed using the intraclass correlation coefficient (ICC). The typical error of measurement (absolute reliability) of intraday and interday lnRMSSD assessments was analyzed using the coefficient of variation (CV). Both intraday (ICC = 0.96; CV = 3.99%) and interday (ICC = 0.90; CV = 7.65%) measures were highly reliable. The ultra-short-term lnRMSSD is a consistent measure for evaluating elite rugby union players, in both intraday and interday settings. This study provides further validity to using this shortened method in practical field conditions with highly trained team sports athletes.

Multiple Myeloma and Glyphosate Use: A Re-Analysis of US Agricultural Health Study (AHS) Data

PubMed Central

Sorahan, Tom

2015-01-01

A previous publication of 57,311 pesticide applicators enrolled in the US Agricultural Health Study (AHS) produced disparate findings in relation to multiple myeloma risks in the period 1993–2001 and ever-use of glyphosate (32 cases of multiple myeloma in the full dataset of 54,315 applicators without adjustment for other variables: rate ratio (RR) 1.1, 95% confidence interval (CI) 0.5 to 2.4; 22 cases of multiple myeloma in restricted dataset of 40,719 applicators with adjustment for other variables: RR 2.6, 95% CI 0.7 to 9.4). It seemed important to determine which result should be preferred. RRs for exposed and non-exposed subjects were calculated using Poisson regression; subjects with missing data were not excluded from the main analyses. Using the full dataset adjusted for age and gender the analysis produced a RR of 1.12 (95% CI 0.50 to 2.49) for ever-use of glyphosate. Additional adjustment for lifestyle factors and use of ten other pesticides had little effect (RR 1.24, 95% CI 0.52 to 2.94). There were no statistically significant trends for multiple myeloma risks in relation to reported cumulative days (or intensity weighted days) of glyphosate use. The doubling of risk reported previously arose from the use of an unrepresentative restricted dataset and analyses of the full dataset provides no convincing evidence in the AHS for a link between multiple myeloma risk and glyphosate use. PMID:25635915

Multiple myeloma and glyphosate use: a re-analysis of US Agricultural Health Study (AHS) data.

PubMed

Sorahan, Tom

2015-01-28

A previous publication of 57,311 pesticide applicators enrolled in the US Agricultural Health Study (AHS) produced disparate findings in relation to multiple myeloma risks in the period 1993-2001 and ever-use of glyphosate (32 cases of multiple myeloma in the full dataset of 54,315 applicators without adjustment for other variables: rate ratio (RR) 1.1, 95% confidence interval (CI) 0.5 to 2.4; 22 cases of multiple myeloma in restricted dataset of 40,719 applicators with adjustment for other variables: RR 2.6, 95% CI 0.7 to 9.4). It seemed important to determine which result should be preferred. RRs for exposed and non-exposed subjects were calculated using Poisson regression; subjects with missing data were not excluded from the main analyses. Using the full dataset adjusted for age and gender the analysis produced a RR of 1.12 (95% CI 0.50 to 2.49) for ever-use of glyphosate. Additional adjustment for lifestyle factors and use of ten other pesticides had little effect (RR 1.24, 95% CI 0.52 to 2.94). There were no statistically significant trends for multiple myeloma risks in relation to reported cumulative days (or intensity weighted days) of glyphosate use. The doubling of risk reported previously arose from the use of an unrepresentative restricted dataset and analyses of the full dataset provides no convincing evidence in the AHS for a link between multiple myeloma risk and glyphosate use.

Chronic orthostatic intolerance: a disorder with discordant cardiac and vascular sympathetic control

NASA Technical Reports Server (NTRS)

Furlan, R.; Jacob, G.; Snell, M.; Robertson, D.; Porta, A.; Harris, P.; Mosqueda-Garcia, R.

1998-01-01

BACKGROUND: Chronic orthostatic intolerance (COI) is a debilitating autonomic condition in young adults. Its neurohumoral and hemodynamic profiles suggest possible alterations of postural sympathetic function and of baroreflex control of heart rate (HR). METHODS AND RESULTS: In 16 COI patients and 16 healthy volunteers, intra-arterial blood pressure (BP), ECG, central venous pressure (CVP), and muscle sympathetic nerve activity (MSNA) were recorded at rest and during 75 degrees tilt. Spectral analysis of RR interval and systolic arterial pressure (SAP) variabilities provided indices of sympathovagal modulation of the sinoatrial node (ratio of low-frequency to high-frequency components, LF/HF) and of sympathetic vasomotor control (LFSAP). Baroreflex mechanisms were assessed (1) by the slope of the regression line obtained from changes of RR interval and MSNA evoked by pharmacologically induced alterations in BP and (2) by the index alpha, obtained from cross-spectral analysis of RR and SAP variabilities. At rest, HR, MSNA, LF/HF, and LFSAP were higher in COI patients, whereas BP and CVP were similar in the two groups. During tilt, BP did not change and CVP fell by the same extent in the 2 groups; the increase of HR and LF/HF was more pronounced in COI patients. Conversely, the increase of MSNA was lower in COI than in control subjects. Baroreflex sensitivity was similar in COI and control subjects at rest; tilt reduced alpha similarly in both groups. CONCLUSIONS: COI is characterized by an overall enhancement of noradrenergic tone at rest and by a blunted postganglionic sympathetic response to standing, with a compensatory cardiac sympathetic overactivity. Baroreflex mechanisms maintain their functional responsiveness. These data suggest that in COI, the functional distribution of central sympathetic tone to the heart and vasculature is abnormal.

Episiotomy and its relationship to various clinical variables that influence its performance

PubMed Central

Ballesteros-Meseguer, Carmen; Carrillo-García, César; Meseguer-de-Pedro, Mariano; Canteras-Jordana, Manuel; Martínez-Roche, Mª Emilia

2016-01-01

Objective: to understand the episiotomy rate and its relationship with various clinical variables. Method: a descriptive, cross-sectional, analytic study of 12,093 births in a tertiary hospital. Variables: Parity, gestational age, start of labor, use of epidural analgesia, oxytocin usage, position during fetal explusion, weight of neonate, and completion of birth. The analysis was performed with SPSS 19.0. Results: the global percentage of episiotomies was 50%. The clinical variables that presented a significant association were primiparity (RR=2.98), gestational age >41 weeks (RR=1.2), augmented or induced labor (RR=1.33), epidural analgesia use (RR=1,95), oxytocin use (RR=1.58), lithotomy position during fetal expulsion (RR=6.4), and instrumentation (RR=1.84). Furthermore, maternal age ≥35 years (RR=0.85) and neonatal weight <2500 g (RR=0.8) were associated with a lower incidence of episiotomy. Conclusions: episiotomy is dependent on obstetric interventions performed during labor. If we wish to reduce the episiotomy rate, it will be necessary to bear in mind these risk factors when establishing policies for reducing this procedure. PMID:27224064

Variability of the human heart rate as a diagnostic instrument obtained by mean of a wireless monitor

NASA Astrophysics Data System (ADS)

Barajas Mauricio, Sánchez; Hernández González, Martha Alicia; Figueroa Vega, Nicte; Malacara Hernández, Juan Manuel; Fraga Teodoro, Córdova

2014-11-01

Introduction: Heart rate variability (HRV) is the cyclic measurement of RR intervals between normal beats. Aim: To determine the VFC via a wireless Polar monitor. Material and methods: 100 symptomatic menopausal women were studied for measurements of HRV were I post a Polar RS400 Watch four hrs. Results: Obtained through the fast Fourier transform, the frequency domain HRV low frequency (LF) 0.04-0.15 Hz, high frequency (HF) 0.15-0.4Hz and the ratio LF / HF. Conclusion: obtaining HRV is important for cardiovascular autonomic assessment in menopausal women.

Fourier Analysis of First-Overtone RR Lyrae Variables in the LMC

NASA Astrophysics Data System (ADS)

Clement, C. M.; Muzzin, A. V.; Rowe, J. F.; MACHO Collaboration

2002-05-01

Simon's (1989, ApJ, 343, L17) Fourier decomposition technique has been applied to the V magnitudes of the first-overtone RR Lyrae (RR1) variables in 16 LMC fields observed by the MACHO collaboration. The Fourier coefficients R21 and φ 31 derived for these stars have been compared with the coefficients of RR1 variables in the galactic globular clusters Omega Centauri, M2, M3, M5, M68, M107 (NGC 6171) and NGC 6441. Our analysis indicates that the majority of the LMC RR1 variables have coefficients similar to those in the Oosterhoff type I (OoI) clusters M3 and M5 and to the OoI variables in Omega Centauri. In a study of hydrodynamic pulsation models of first overtone RR Lyrae variables, Simon & Clement (1993, ApJ, 410, 526) found that the Fourier phase parameter φ 31 depends essentially on mass and luminosity. From this, we conclude that the masses and luminosities of most of the RR1 variables in the LMC are comparable to those of the OoI RR1 variables in Omega Centauri, M3 and M5, a fact that should be considered when RR Lyrae variables are used for determining the distance to the LMC. The MACHO collaboration includes C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennet, K. H. Cook, A. J. Drake, K. C. Freeman, M. Geha, K. Griest, M. J. Lehner, S. L. Marshall, D. Minniti, C. A. Nelson, B. A. Peterson, P. Popowski, M. R. Pratt, P. J. Quinn, C. W. Stubbs, W. Sutherland, T. Vandehel and D. L. Welch. This research has been supported in part by the Natural Sciences and Engineering Research Council of Canada.

Variability in case-mix adjusted in-hospital cardiac arrest rates.

PubMed

Merchant, Raina M; Yang, Lin; Becker, Lance B; Berg, Robert A; Nadkarni, Vinay; Nichol, Graham; Carr, Brendan G; Mitra, Nandita; Bradley, Steven M; Abella, Benjamin S; Groeneveld, Peter W

2012-02-01

It is unknown how in-hospital cardiac arrest (IHCA) rates vary across hospitals and predictors of variability. Measure variability in IHCA across hospitals and determine if hospital-level factors predict differences in case-mix adjusted event rates. Get with the Guidelines Resuscitation (GWTG-R) (n=433 hospitals) was used to identify IHCA events between 2003 and 2007. The American Hospital Association survey, Medicare, and US Census were used to obtain detailed information about GWTG-R hospitals. Adult patients with IHCA. Case-mix-adjusted predicted IHCA rates were calculated for each hospital and variability across hospitals was compared. A regression model was used to predict case-mix adjusted event rates using hospital measures of volume, nurse-to-bed ratio, percent intensive care unit beds, palliative care services, urban designation, volume of black patients, income, trauma designation, academic designation, cardiac surgery capability, and a patient risk score. We evaluated 103,117 adult IHCAs at 433 US hospitals. The case-mix adjusted IHCA event rate was highly variable across hospitals, median 1/1000 bed days (interquartile range: 0.7 to 1.3 events/1000 bed days). In a multivariable regression model, case-mix adjusted IHCA event rates were highest in urban hospitals [rate ratio (RR), 1.1; 95% confidence interval (CI), 1.0-1.3; P=0.03] and hospitals with higher proportions of black patients (RR, 1.2; 95% CI, 1.0-1.3; P=0.01) and lower in larger hospitals (RR, 0.54; 95% CI, 0.45-0.66; P<0.0001). Case-mix adjusted IHCA event rates varied considerably across hospitals. Several hospital factors associated with higher IHCA event rates were consistent with factors often linked with lower hospital quality of care.

ECG-ViEW II, a freely accessible electrocardiogram database

PubMed Central

Park, Man Young; Lee, Sukhoon; Jeon, Min Seok; Yoon, Dukyong; Park, Rae Woong

2017-01-01

The Electrocardiogram Vigilance with Electronic data Warehouse II (ECG-ViEW II) is a large, single-center database comprising numeric parameter data of the surface electrocardiograms of all patients who underwent testing from 1 June 1994 to 31 July 2013. The electrocardiographic data include the test date, clinical department, RR interval, PR interval, QRS duration, QT interval, QTc interval, P axis, QRS axis, and T axis. These data are connected with patient age, sex, ethnicity, comorbidities, age-adjusted Charlson comorbidity index, prescribed drugs, and electrolyte levels. This longitudinal observational database contains 979,273 electrocardiograms from 461,178 patients over a 19-year study period. This database can provide an opportunity to study electrocardiographic changes caused by medications, disease, or other demographic variables. ECG-ViEW II is freely available at http://www.ecgview.org. PMID:28437484

Nine months in space: effects on human autonomic cardiovascular regulation.

PubMed

Cooke, W H; Ames JE, I V; Crossman, A A; Cox, J F; Kuusela, T A; Tahvanainen, K U; Moon, L B; Drescher, J; Baisch, F J; Mano, T; Levine, B D; Blomqvist, C G; Eckberg, D L

2000-09-01

We studied three Russian cosmonauts to better understand how long-term exposure to microgravity affects autonomic cardiovascular control. We recorded the electrocardiogram, finger photoplethysmographic pressure, and respiratory flow before, during, and after two 9-mo missions to the Russian space station Mir. Measurements were made during four modes of breathing: 1) uncontrolled spontaneous breathing; 2) stepwise breathing at six different frequencies; 3) fixed-frequency breathing; and 4) random-frequency breathing. R wave-to-R wave (R-R) interval standard deviations decreased in all and respiratory frequency R-R interval spectral power decreased in two cosmonauts in space. Two weeks after the cosmonauts returned to Earth, R-R interval spectral power was decreased, and systolic pressure spectral power was increased in all. The transfer function between systolic pressures and R-R intervals was reduced in-flight, was reduced further the day after landing, and had not returned to preflight levels by 14 days after landing. Our results suggest that long-duration spaceflight reduces vagal-cardiac nerve traffic and decreases vagal baroreflex gain and that these changes may persist as long as 2 wk after return to Earth.

Stereotactic radiosurgery alone versus resection plus whole-brain radiotherapy for 1 or 2 brain metastases in recursive partitioning analysis class 1 and 2 patients.

PubMed

Rades, Dirk; Bohlen, Guenther; Pluemer, Andre; Veninga, Theo; Hanssens, Patrick; Dunst, Juergen; Schild, Steven E

2007-06-15

The objective of this study was to compare stereotactic radiosurgery (SRS) alone with resection plus whole-brain radiotherapy (WBRT) for the treatment of patients in recursive partitioning analysis (RPA) class 1 and 2 who had 1 or 2 brain metastases. Two hundred six patients in RPA class 1 and 2 who had 1 or 2 brain metastases were analyzed retrospectively. Patients in Group A (n = 94) received from 18 grays (Gy) to 25 Gy SRS, and patients in Group B (n = 112) underwent resection of their metastases and received 10 x 3 Gy/20 x 2 Gy WBRT. Eight other potential prognostic factors were evaluated regarding overall survival (OS), brain control (BC), and local control (LC) of treated metastases: age, sex, performance status, tumor type, number of brain metastases, extracranial metastases, RPA class, and interval from tumor diagnosis to treatment of brain metastases. A comparison of the 2 treatment groups did not reveal significantly different OS (P = .19), BC (P = .52), or LC (P = .25). In RPA subgroup analyses, outcome also did not differ significantly for either RPA class of patients (P values from .21 to .83). On multivariate analysis, improved OS was associated with age < or =60 years (relative risk [RR], 1.75; P = .002), better performance status (RR, 1.67; P = .015), no extracranial metastases (RR, 2.84; P < .001), interval from tumor diagnosis to treatment >12 months (RR, 1.70; P = .003), and RPA class 1 (RR, 1.51; P = .016). Improved BC was associated with a single metastasis (RR, 1.54; P = .034) and an interval from tumor diagnosis to treatment >12 months (RR, 1.58; P = .019), and improved LC was associated with an interval from tumor diagnosis to treatment >12 months (RR, 1.59; P = .047). SRS alone appeared to be as effective as resection plus WBRT in the treatment of 1 or 2 brain metastases for patients in RPA class 1 and 2. Patient outcomes were associated with age, Karnofsky performance status, number of brain metastases, extracranial metastases, RPA class, and interval from tumor diagnosis to treatment. Copyright 2007 American Cancer Society.

Heart rate variability during carbachol-induced REM sleep and cataplexy.

PubMed

Torterolo, Pablo; Castro-Zaballa, Santiago; Cavelli, Matías; Velasquez, Noelia; Brando, Victoria; Falconi, Atilio; Chase, Michael H; Migliaro, Eduardo R

2015-09-15

The nucleus pontis oralis (NPO) exerts an executive control over REM sleep. Cholinergic input to the NPO is critical for REM sleep generation. In the cat, a single microinjection of carbachol (a cholinergic agonist) into the NPO produces either REM sleep (REMc) or wakefulness with muscle atonia (cataplexy, CA). In order to study the central control of the heart rate variability (HRV) during sleep, we conducted polysomnographic and electrocardiogram recordings from chronically prepared cats during REMc, CA as well as during sleep and wakefulness. Subsequently, we performed statistical and spectral analyses of the HRV. The heart rate was greater during CA compared to REMc, NREM or REM sleep. Spectral analysis revealed that the low frequency band (LF) power was significantly higher during REM sleep in comparison to REMc and CA. Furthermore, we found that during CA there was a decrease in coupling between the RR intervals plot (tachogram) and respiratory activity. In contrast, compared to natural behavioral states, during REMc and CA there were no significant differences in the HRV based upon the standard deviation of normal RR intervals (SDNN) and the mean squared difference of successive intervals (rMSSD). In conclusion, there were differences in the HRV during naturally-occurring REM sleep compared to REMc. In addition, in spite of the same muscle atonia, the HRV was different during REMc and CA. Therefore, the neuronal network that controls the HRV during REM sleep can be dissociated from the one that generates the muscle atonia during this state. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of age on the cardiac and vascular limbs of the arterial baroreflex.

PubMed

Brown, C M; Hecht, M J; Weih, A; Neundörfer, B; Hilz, M J

2003-01-01

Healthy ageing has several effects on the autonomic control of the circulation. Several studies have shown that baroreflex-mediated vagal control of the heart deteriorates with age, but so far there is little information regarding the effect of ageing on sympathetically mediated baroreflex responses. The aim of this study was to assess the effects of ageing on baroreflex control of the heart and blood vessels. In 40 healthy volunteers, aged 20-87 years, we applied oscillatory neck suction at 0.1 Hz to assess the sympathetic modulation of the heart and blood vessels and at 0.2 Hz to assess the effect of parasympathetic stimulation on the heart. Breathing was maintained at 0.25 Hz. Blood pressure, electrocardiographic RR intervals and respiration were recorded continuously. Spectral analysis was used to evaluate the magnitude of the low-frequency (0.03-0.14 Hz) and high-frequency (0.15-0.50 Hz) oscillations in the RR interval and blood pressure. Responses to neck suction were assessed as the change in power of the RR interval and blood pressure fluctuations at the stimulation frequency from baseline values. Resting low- and high-frequency powers of the RR interval decreased significantly with age (P < 0.01). However, the low-frequency power of systolic blood pressure did not correlate with age. Spontaneous baroreflex sensitivity (alpha-index) showed a significant inverse correlation with age (r = -0.46, P < 0.05). Responses of the RR interval and systolic blood pressure to 0.1 Hz neck suction stimulation were not related to age, however, the RR interval response to 0.2 Hz neck suction declined significantly with age (r = -0.61, P < 0.01). These results confirm an age-related decrease in cardiovagal baroreflex responses. However, sympathetically mediated baroreflex control of the blood vessels is preserved with age.

[Influence of geomagnetic storms on the balance of autonomic regulatory mechanisms].

PubMed

Chichinadze, G; Tvildiani, L; Kvachadze, I; Tarkhan-Mouravi, I

2005-09-01

The investigation aimed to evaluate autonomic regulatory mechanisms in practically healthy persons during the geomagnetically quiet periods and during geomagnetic storms. The examinations were conducted among the volunteer young men (n=64) 18-22 years of age. The autonomic function was studied on the basis of the heart rate variability. The geomagnetically quiet periods were considered when the value of the K-index was no more then 2 and a geomagnetic storm was considered when the value of the index was 5 and more. It is ascertained that in the both cases the basic statistical indices of the heart rate were identical. The analysis of R-R intervals spectral power gave the possibility to sort the persons examined into the three different groups. The data obtained allowed to suggest that geomagnetic storms influence human organisms through the vagus centers by means of their excitation. This phenomenon may be considered as a self-regulatory physiologic mechanism of the adaptive character. The analysis of the spectral power of R-R intervals may be considered as a sensitive method for the detection of the magnitolabile persons.

Heart rate variability analysed by Poincaré plot in patients with metabolic syndrome.

PubMed

Kubičková, Alena; Kozumplík, Jiří; Nováková, Zuzana; Plachý, Martin; Jurák, Pavel; Lipoldová, Jolana

2016-01-01

The SD1 and SD2 indexes (standard deviations in two orthogonal directions of the Poincaré plot) carry similar information to the spectral density power of the high and low frequency bands but have the advantage of easier calculation and lesser stationarity dependence. ECG signals from metabolic syndrome (MetS) and control group patients during tilt table test under controlled breathing (20 breaths/minute) were obtained. SD1, SD2, SDRR (standard deviation of RR intervals) and RMSSD (root mean square of successive differences of RR intervals) were evaluated for 31 control group and 33 MetS subjects. Statistically significant lower values were observed in MetS patients in supine position (SD1: p=0.03, SD2: p=0.002, SDRR: p=0.006, RMSSD: p=0.01) and during tilt (SD2: p=0.004, SDRR: p=0.007). SD1 and SD2 combining the advantages of time and frequency domain methods, distinguish successfully between MetS and control subjects. Copyright © 2016 Elsevier Inc. All rights reserved.

Heart rate dynamics in monoamine oxidase-A- and -B-deficient mice

PubMed Central

HOLSCHNEIDER, D. P.; SCREMIN, O. U.; CHIALVO, D. R.; CHEN, K.; SHIH, J. C.

2014-01-01

Heart rate (HR) dynamics were investigated in mice deficient in monoamine oxidase A and B, whose phenotype includes elevated tissue levels of norepinephrine, serotonin, dopamine, and phenylethylamine. In their home cages, spectral analysis of R-R intervals revealed more pronounced fluctuations at all frequencies in the mutants compared with wild-type controls, with a particular enhancement at 1–4 Hz. No significant genotypic differences in HR variability (HRV) or entropies calculated from Poincaré plots of the R-R intervals were noted. During exposure to the stress of a novel environment, HR increased and HRV decreased in both genotypes. However, mutants, unlike controls, demonstrated a rapid return to baseline HR during the 10-min exposure. Such modulation may result from an enhanced vagal tone, as suggested by the observation that mutants responded to cholinergic blockade with a decrease in HRV and a prolonged tachycardia greater than controls. Monoamine oxidase-deficient mice may represent a useful experimental model for studying compensatory mechanisms responsible for changes in HR dynamics in chronic states of high sympathetic tone. PMID:11959640

Oral Contraceptives Attenuate Cardiac Autonomic Responses to Musical Auditory Stimulation: Pilot Study.

PubMed

Milan, Réveni Carmem; Plassa, Bruna Oliveira; Guida, Heraldo Lorena; de Abreu, Luiz Carlos; Gomes, Rayana L; Garner, David M; Valenti, Vitor E

2015-01-01

The literature presents contradictory results regarding the effects of contraceptives on cardiac autonomic regulation. The research team aimed to evaluate the effects of musical auditory stimulation on cardiac autonomic regulation in women who use oral contraceptives. The research team designed a transversal observational pilot study. The setting was the Centro de Estudos do Sistema Nervoso Autônomo (CESNA) in the Departamento de Fonoaudiologia at the Universidade Estadual Paulista (UNESP) in Marília, SP, Brazil. Participants were 22 healthy nonathletic and nonsedentary females, all nonsmokers and aged between 18 and 27 y. Participants were divided into 2 groups: (1) 12 women who were not taking oral contraceptives, the control group; and (2) 10 women who were taking oral contraceptives, the oral contraceptive group. In the first stage, a rest control, the women sat with their earphones turned off for 20 min. After that period, the participants were exposed to 20 min of classical baroque music (ie, "Canon in D Major," Johann Pachelbel), at 63-84 dB. Measurements of the equivalent sound levels were conducted in a soundproof room, and the intervals between consecutive heartbeats (R-R intervals) were recorded, with a sampling rate of 1000 Hz. For calculation of the linear indices, the research team used software to perform an analysis of heart rate variability (HRV). Linear indices of HRV were analyzed in the time domain: (1) the standard deviation of normal-to-normal R-R intervals (SDNN), (2) the root-mean square of differences between adjacent normal R-R intervals in a time interval (RMSSD), and (3) the percentage of adjacent R-R intervals with a difference of duration greater than 50 ms (pNN50). The study also analyzed the frequency domain-low frequency (LF), high frequency (HF), and LF/HF ratio. For the control group, the musical auditory stimulation reduced (1) the SDNN from 52.2 ± 10 ms to 48.4 ± 16 ms (P = .0034); (2) the RMSSD from 45.8 ± 22 ms to 41.2 ± 19 ms (P = .0128); (3) the pNN50 from 25.5 ± 19 to 22.0 ± 18 (P = .0211); and (4) the LF (ms2) from 954.8 ± 457 ms2 to 686.2 ± 491 ms2 (P = .0024). In the oral contraceptive group, no significant changes occurred for the HRV indices during exposure to music. Musical auditory stimulation had a greater influence on cardiac autonomic regulation in women who did not use oral contraceptives.

Rapid-rate nonsustained ventricular tachycardia found on implantable cardioverter-defibrillator interrogation: relationship to outcomes in the SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial).

PubMed

Chen, Jay; Johnson, George; Hellkamp, Anne S; Anderson, Jill; Mark, Daniel B; Lee, Kerry L; Bardy, Gust H; Poole, Jeanne E

2013-05-28

The aim of this study was to examine rapid-rate nonsustained ventricular tachycardia (RR-NSVT) during routine implantable cardioverter-defibrillator (ICD) evaluation in patients with heart failure and its relationship to outcomes. The clinical implications of RR-NSVT identified during routine ICD interrogation are unclear. In this study, the occurrence of RR-NSVT and its association with ICD shocks and mortality in SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) were examined. The 811 patients who received ICDs in SCD-HeFT constituted the study population. The occurrence of RR-NSVT and its association with ICD shocks and mortality in SCD-HeFT were examined. RR-NSVT was documented on ICD interrogation in 186 of 811 patients (22.9%). The mean duration of RR-NSVT was 26.4 ± 9.1 beats (7.5 ± 2.6 s), with a mean cycle length of 259 ± 32 ms. Polymorphic RR-NSVT accounted for 56% of episodes. Compared with patients without RR-NSVT, those with RR-NSVT were less likely to be taking beta-blockers, statins, or aspirin at enrollment. After adjusting for other known predictors of mortality in SCD-HeFT, RR-NSVT was independently associated with appropriate ICD shocks (hazard ratio: 4.25; 95% confidence interval: 2.94 to 6.14; p < 0.0001), with all-cause mortality (hazard ratio: 2.40; 95% confidence interval: 1.62 to 3.54; p < 0.0001), and with a composite of all-cause mortality and appropriate ICD shocks (hazard ratio: 3.03; 95% confidence interval: 2.21 to 4.15; p < 0.0001). RR-NSVT identified on routine ICD interrogation should be considered an important clinical event. RR-NSVT during ICD interrogation is associated with appropriate ICD shocks and all-cause mortality. The clinical evaluation of patients with RR-NSVT should include intensification of medical therapy, particularly beta-blockers, or other appropriate clinical interventions. (Sudden Cardiac Death in Heart Failure Trial [SCD-HeFT]; NCT00000609). Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

A genome-wide interaction analysis of tri/tetracyclic antidepressants and RR and QT intervals: a pharmacogenomics study from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium

PubMed Central

Noordam, Raymond; Sitlani, Colleen M; Avery, Christy L; Stewart, James D; Gogarten, Stephanie M; Wiggins, Kerri L; Trompet, Stella; Warren, Helen R; Sun, Fangui; Evans, Daniel S; Li, Xiaohui; Li, Jin; Smith, Albert V; Bis, Joshua C; Brody, Jennifer A; Busch, Evan L; Caulfield, Mark J; Chen, Yii-Der I; Cummings, Steven R; Cupples, L Adrienne; Duan, Qing; Franco, Oscar H; Méndez-Giráldez, Rául; Harris, Tamara B; Heckbert, Susan R; van Heemst, Diana; Hofman, Albert; Floyd, James S; Kors, Jan A; Launer, Lenore J; Li, Yun; Li-Gao, Ruifang; Lange, Leslie A; Lin, Henry J; de Mutsert, Renée; Napier, Melanie D; Newton-Cheh, Christopher; Poulter, Neil; Reiner, Alexander P; Rice, Kenneth M; Roach, Jeffrey; Rodriguez, Carlos J; Rosendaal, Frits R; Sattar, Naveed; Sever, Peter; Seyerle, Amanda A; Slagboom, P Eline; Soliman, Elsayed Z; Sotoodehnia, Nona; Stott, David J; Stürmer, Til; Taylor, Kent D; Thornton, Timothy A; Uitterlinden, André G; Wilhelmsen, Kirk C; Wilson, James G; Gudnason, Vilmundur; Jukema, J Wouter; Laurie, Cathy C; Liu, Yongmei; Mook-Kanamori, Dennis O; Munroe, Patricia B; Rotter, Jerome I; Vasan, Ramachandran S; Psaty, Bruce M; Stricker, Bruno H; Whitsel, Eric A

2017-01-01

Background Increased heart rate and a prolonged QT interval are important risk factors for cardiovascular morbidity and mortality, and can be influenced by the use of various medications, including tri/tetracyclic antidepressants (TCAs). We aim to identify genetic loci that modify the association between TCA use and RR and QT intervals. Methods and Results We conducted race/ethnic-specific genome-wide interaction analyses (with HapMap Phase II imputed reference panel imputation) of TCAs and resting RR and QT intervals in cohorts of European (n=45,706; n=1,417 TCA users), African (n=10,235; n=296 TCA users) and Hispanic/Latino (n=13,808; n=147 TCA users) ancestry, adjusted for clinical covariates. Among the populations of European ancestry, two genome-wide significant loci were identified for RR interval: rs6737205 in BRE (β = 56.3, Pinteraction = 3.9e−9) and rs9830388 in UBE2E2 (β = 25.2, Pinteraction = 1.7e−8). In Hispanic/Latino cohorts, rs2291477 in TGFBR3 significantly modified the association between TCAs and QT intervals (β = 9.3, Pinteraction = 2.55e−8). In the meta-analyses of the other ethnicities, these loci either were excluded from the meta-analyses (as part of quality control), or their effects did not reach the level of nominal statistical significance (Pinteraction > 0.05). No new variants were identified in these ethnicities. No additional loci were identified after inverse-variance-weighted meta-analysis of the three ancestries. Conclusion Among Europeans, TCA interactions with variants in BRE and UBE2E2, were identified in relation to RR intervals. Among Hispanic/Latinos, variants in TGFBR3 modified the relation between TCAs and QT intervals. Future studies are required to confirm our results. PMID:28039329

Association of functional genetic variants of A-kinase anchoring protein 10 with QT interval length in full-term Polish newborns.

PubMed

Łoniewska, Beata; Kaczmarczyk, Mariusz; Clark, Jeremy Simon; Gorący, Iwona; Horodnicka-Józwa, Anita; Ciechanowicz, Andrzej

2015-03-16

A-Kinase Anchoring Proteins (AKAPs) coordinate the specificity of protein kinase A signaling by localizing the kinase to subcellular sites. The 1936G (V646) AKAP10 allele has been associated in adults with low cholinergic/vagus nerve sensitivity, shortened PR intervals in ECG recording and in newborns with increased blood pressure and higher cholesterol cord blood concentration. The aim of the study was to answer the question of whether 1936A > G AKAP10 polymorphism is associated with the newborn electrocardiographic variables. Electrocardiograms were recorded from 114 consecutive healthy Polish newborns (55 females, 59 males), born after 37 gestational weeks to healthy women with uncomplicated pregnancies. All recordings were made between 3(rd) and 7(th) day of life to avoid QT variability. The heart rate per minute and duration of PR, QRS, RR and QT intervals were usually measured. The ECGs were evaluated independently by three observers. At birth, cord blood of neonates was obtained for isolation of genomic DNA. The distribution of anthropometric and electrocardiographic variables in our cohort approached normality (skewness < 2 for all variables). No significant differences in anthropometric variables and electrocardiographic traits with respect to AKAP10 genotype were found. Multiple regression analysis with adjustment for gender, gestational age and birth mass revealed that QTc interval in GG AKAP10 homozygotes was significantly longer, but in range, when compared with A alleles carriers (AA + AG, recessive mode of inheritance). No rhythm disturbances were observed. Results demonstrate possible association between AKAP10 1936A > G variant and QTc interval in Polish newborns.

Prognostic value of heart rate variability footprint and standard deviation of average 5-minute intrinsic R-R intervals for mortality in cardiac resynchronization therapy patients.

PubMed

Gilliam, F Roosevelt; Singh, Jagmeet P; Mullin, Christopher M; McGuire, Maureen; Chase, Kellie J

2007-10-01

Cardiac resynchronization therapy devices provide effective therapy for heart failure. Heart rate variability (HRV) parameters in the device such as HRV footprint and SD of average 5-minute intrinsic R-R intervals (SDANN) are related to autonomic function and may be used to identify patients with a higher risk of mortality. We examined the relationship between HRV and mortality in a prospective cohort study. The 842 patients (mean age, 67.7 +/- 11.2; 23.5 % female; New York Heart Association class III, 88.6%; class IV, 11.4%) included in the analysis were implanted with a cardiac resynchronization therapy with defibrillation device and had baseline HRV measurements available. During a median of 11.6 months of follow-up, 7.8% (66/842) of patients died. Heart rate variability footprint and SDANN were significant predictors of mortality (all P < .05); patients with lower HRV values were at greater risk for death, compared with patients with higher HRV values. Heart rate variability changes over time tended to predict the risk of mortality in follow-up (P = nonsignificant); patients with low baseline HRV and small changes in HRV during the follow-up period were at the highest risk for death (7% mortality for SDANN and 8.9% for HRV footprint), and patients with high baseline HRV and large changes in HRV were at the lowest risk (1.5% mortality for SDANN and 2.4% for HRV footprint). Results were consistent when adjusted for age, sex, body mass index, and diastolic blood pressure. Continuously measured device HRV parameters provide prognostic information about patient mortality that may be helpful for risk stratification.

Influence of the hypothalamic paraventricular nucleus (PVN) on heart rate variability (HRV) in rat hearts via electronic lesion.

PubMed

Deng, Xin; Feng, Xuhui; Li, Sen; Gao, Ya; Yu, Bingzhi; Li, Gensong

2015-01-01

Previous literatures have indicated that hypothalamic paraventricular nucleus (PVN) neurons are important for regulating the level of sympathetic and vagal nervous activity. Sympathovagal balance is closely related to heart rate variability (HRV). However, it still requires further elucidation regarding the effect of PVN on HRV by regulating sympathovagal balance. To detect the influence of the PVN on HRV, we evaluated the changes in time domain (including standard deviation of the R-R intervals (SDNN), and the root mean square of successive differences (RMSSD)) and frequency domain (including low frequency (LFnu), high frequency (HFnu) and the ratio of LF/HF) in HRV upon appropriate electronic stimulation, and lesions on the PVN of the rat in vivo. Cardiac vagal modulation was evaluated by HFnu; sympathetic modulation was evaluated by LFnu. Sympathovagal balance was evaluated by LF/HF and SDNN. Upon electronic stimulating (less than 0.6 mA) to the PVN of rats, we found that LFnu and HFnu changed correspondingly but recovered after the stimulation. When the PVN of the rats was injured, the RR intervals were enhanced with the rats' unilaterally or bilaterally injured PVN, especially the bilateral lesion. Meanwhile, LFnu, LF/HF and SDNN decreased gradually, accompanied with an increase of HFnu levels. So these PVN changes may indicate alterations of the sympathovagal balance.

[The influence of physical exercise on heart rate variability].

PubMed

Gajek, Jacek; Zyśko, Dorota; Negrusz-Kawecka, Marta; Halawa, Bogumił

2003-03-01

Heart rate variability is controlled by the influence of autonomic nervous system, whereas one part of the system modulates the activity of the other. There is evidence of increased sympathetic activity in patients (pts) with essential hypertension. The aim of the study was to assess the persisting influence of increased sympathetic activity 30 min after moderate physical exercise on heart rate variability in patients with arterial hypertension. The study was performed in 19 patients (10 women, mean age 52.7 +/- 9.5 years and 9 men, mean age 37.7 +/- 8.8 years) with stage I (6 pts) and stage II (13 pts) arterial hypertension. All studied pts had sinus rhythm, were free of diabetes, coronary heart disease and congestive heart failure. 24-hour Holter monitoring was performed and for 30 min before the exercise test the pts stayed in supine rest. The exercise tests were performed between 10 and 11 a.m. Immediately after the exercise all pts stayed in supine position for 30 min. The heart rate variability parameters were studied using Holter monitoring system Medilog Optima Jet and were then analysed statistically. The mean energy expenditure during the exercise was 5.8 +/- 1.1 METs and the maximal heart rate was 148.1 +/- 20.3 bpm. All studied HRV parameters were significantly different in the assessed time period compared to the baseline values (p < 0.001). Significant correlation was found between the age of the studied patients and the mean RR interval, what can be considered as a hyperkinetic (hyperadrenergic) circulatory status and shorter RR interval in younger pts. Significant negative correlation between the age and SDNN parameter (r = -0.65, p < 0.001), 30 min after the exercise mirrors the prolonged adrenergic influence in older pts. The present study shows that the influence of moderate physical exercise on heart rate variability in pts with essential hypertension is extended over 30 min period after exercise and is more pronounced in older pts. The studies on HRV should be performed at longer time intervals after exercise.

Documenting Penicillin Allergy: The Impact of Inconsistency

PubMed Central

Shah, Nirav S.; Ridgway, Jessica P.; Pettit, Natasha; Fahrenbach, John; Robicsek, Ari

2016-01-01

Background Allergy documentation is frequently inconsistent and incomplete. The impact of this variability on subsequent treatment is not well described. Objective To determine how allergy documentation affects subsequent antibiotic choice. Design Retrospective, cohort study. Participants 232,616 adult patients seen by 199 primary care providers (PCPs) between January 1, 2009 and January 1, 2014 at an academic medical system. Main Measures Inter-physician variation in beta-lactam allergy documentation; antibiotic treatment following beta-lactam allergy documentation. Key Results 15.6% of patients had a reported beta-lactam allergy. Of those patients, 39.8% had a specific allergen identified and 22.7% had allergic reaction characteristics documented. Variation between PCPs was greater than would be expected by chance (all p<0.001) in the percentage of their patients with a documented beta-lactam allergy (7.9% to 24.8%), identification of a specific allergen (e.g. amoxicillin as opposed to “penicillins”) (24.0% to 58.2%) and documentation of the reaction characteristics (5.4% to 51.9%). After beta-lactam allergy documentation, patients were less likely to receive penicillins (Relative Risk [RR] 0.16 [95% Confidence Interval: 0.15–0.17]) and cephalosporins (RR 0.28 [95% CI 0.27–0.30]) and more likely to receive fluoroquinolones (RR 1.5 [95% CI 1.5–1.6]), clindamycin (RR 3.8 [95% CI 3.6–4.0]) and vancomycin (RR 5.0 [95% CI 4.3–5.8]). Among patients with beta-lactam allergy, rechallenge was more likely when a specific allergen was identified (RR 1.6 [95% CI 1.5–1.8]) and when reaction characteristics were documented (RR 2.0 [95% CI 1.8–2.2]). Conclusions Provider documentation of beta-lactam allergy is highly variable, and details of the allergy are infrequently documented. Classification of a patient as beta-lactam allergic and incomplete documentation regarding the details of the allergy lead to beta-lactam avoidance and use of other antimicrobial agents, behaviors that may adversely impact care quality and cost. PMID:26981866

Very low frequency oscillations in the power spectra of heart rate variability during dry supine immersion and exposure to non-hypoxic hypobaria.

PubMed

Tripathi, K K

2011-06-01

The origin of very low frequency (VLF) oscillations in the power spectra of heart rate variability (HRV) is controversial with possible mechanisms involving thermoregulation and/or renin-angiotensin-aldosterone system. Recently, a major contribution from vagal influences has been suggested. The present study investigated the behaviour of VLF (0.004-0.040 Hz) components of HRV power spectra in a group of healthy male volunteers during their exposure to (1) dry, supine, immersion in thermo-neutral water for 6 h (n = 7) and (2) non-hypoxic hypobaria (breathing 40-60% oxygen at 15,000' simulated in a decompression chamber) for 5 h (n = 15). The two manoeuvres are established to increase vagal outflow. During both the manoeuvres, all the frequency domain indices of HRV exhibited a significant increase. Increase in HRV was much more than that in the R-R interval. At 6 h of immersion, the R-R interval increased by ∼ 15% but the total power increased ∼ fourfold. Similarly, at 5 h of exposure to hypobaria, total power increased ∼ twofold with a very modest increase in an R-R of ∼ 9%. Increase in spectral power was appreciable even after normalization with mean R-R(2). Increase in VLF during immersion was more than reported during enalaprilat blockade of angiotensin convertase enzyme. Plasma renin activity did not vary during hypobaria. There was a significant increase in pNN50, an established marker of cardiac vagal activity. Centre frequencies of the spectra and slope (β) of the relation between log(PSD) and log(frequency) did not change. Results were supportive of the notion that the parasympathetic system is pre-potent to influence slower (than respiratory) frequency components in HRV spectrum. Additionally, such an effect was without a change in the time constant of effector responses or pacemaker frequencies of VLF and LF periodicities and HRV was not a simple linear surrogate for cardiac vagal effects. An invariance of spectral exponent (β) ruled out contamination of VLF and LF spectra from fractal power as an alternate explanation.

Heart rate variability (HRV) and muscular system activity (EMG) in cases of crash threat during simulated driving of a passenger car.

PubMed

Zużewicz, Krystyna; Roman-Liu, Danuta; Konarska, Maria; Bartuzi, Paweł; Matusiak, Krzysztof; Korczak, Dariusz; Lozia, Zbigniew; Guzek, Marek

2013-10-01

The aim of the study was to verify whether simultaneous responses from the muscular and circulatory system occur in the driver's body under simulated conditions of a crash threat. The study was carried out in a passenger car driving simulator. The crash was included in the driving test scenario developed in an urban setting. In the group of 22 young male subjects, two physiological signals - ECG and EMG were continuously recorded. The length of the RR interval in the ECG signal was assessed. A HRV analysis was performed in the time and frequency domains for 1-minute record segments at rest (seated position), during undisturbed driving as well as during and several minutes after the crash. For the left and right side muscles: m. trapezius (TR) and m. flexor digitorum superficialis (FDS), the EMG signal amplitude was determined. The percentage of maximal voluntary contraction (MVC) was compared during driving and during the crash. As for the ECG signal, it was found that in most of the drivers changes occurred in the parameter values reflecting HRV in the time domain. Significant changes were noted in the mean length of RR intervals (mRR). As for the EMG signal, the changes in the amplitude concerned the signal recorded from the FDS muscle. The changes in ECG and EMG were simultaneous in half of the cases. Such parameters as mRR (ECG signal) and FDS-L amplitude (EMG signal) were the responses to accident risk. Under simulated conditions, responses from the circulatory and musculoskeletal systems are not always simultaneous. The results indicate that a more complete driver's response to a crash in road traffic is obtained based on parallel recording of two physiological signals (ECG and EMG).

Impact of using different blood donor subpopulations and models on the estimation of transfusion transmission residual risk of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus in Zimbabwe.

PubMed

Mapako, Tonderai; Janssen, Mart P; Mvere, David A; Emmanuel, Jean C; Rusakaniko, Simbarashe; Postma, Maarten J; van Hulst, Marinus

2016-06-01

Various models for estimating the residual risk (RR) of transmission of infections by blood transfusion have been published mainly based on data from high-income countries. However, to obtain the data required for such an assessment remains challenging for most developing settings. The National Blood Service Zimbabwe (NBSZ) adapted a published incidence-window period (IWP) model, which has less demanding data requirements. In this study we assess the impact of various definitions of blood donor subpopulations and models on RR estimates. We compared the outcomes of two published models and an adapted NBSZ model. The Schreiber IWP model (Model 1), an amended version (Model 2), and an adapted NBSZ model (Model 3) were applied. Variably the three models include prevalence, incidence, preseroconversion intervals, mean lifetime risk, and person-years at risk. Annual mean RR estimates and 95% confidence intervals for each of the three models for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were determined using NBSZ blood donor data from 2002 through 2011. The annual mean RR estimates for Models 1 through 3 were 1 in 6542, 5805, and 6418, respectively for HIV; 1 in 1978, 2027, and 1628 for HBV; and 1 in 9588, 15,126, and 7750, for HCV. The adapted NBSZ model provided comparable results to the published methods and these highlight the high occurrence of HBV in Zimbabwe. The adapted NBSZ model could be used as an alternative to estimate RRs when in settings where two repeat donations are not available. © 2016 AABB.

Fourier Decomposition and Properties of the Variable Stars in the Globular Cluster NGC 4833

NASA Astrophysics Data System (ADS)

Reed, Hunter M.; Pajkos, Michael A.; Murphy, Brian W.; Darragh, Andrew

2016-01-01

Globular clusters provide an ideal setting to study stellar evolution of stars of similar composition and age. RR Lyrae stars found in globular clusters have a variety of uses in probing the physical characteristics of the stellar population itself and its evolution. Building upon our previous study, we focus on the RR Lyrae stars in the globular cluster NGC 4833. From March through June 2014, we used the Southeastern Association for Research in Astronomy 0.6-meter telescope located at CTIO to collect nearly 1,500 images of NGC 4833 in the B, V, R, and I bands. Using difference image analysis we identified 40 variable stars. Of these, 20 were RR Lyrae stars with 10 being of type RR0, 7 of type RR1, and 3 of type RR2. Additionally, 6 SX Phe, 5 eclipsing binaries, and 9 long period variables were identified. The average period of the type RR0, RR1, and RR2 type variables were 0.69597 days, 0.39547 days, and 0.30654 days, respectively. The periods of the RR Lyrae stars and ratio of N1/(N0+N1) of 0.41 is indicative of an Oosterhoff Type II cluster. The observations of the RR Lyrae stars were of very high quality and phase coverage allowing us to perform Fourier decomposition of their light curves. From this Fourier decomposition we were able to determine the physical characteristics of the RR Lyrae stars. We found the mean iron abundance to be [Fe/H]JKZW = -1.87 ± 0.06, the mean apparent V-magnitude RR0 and RR1 type variables to be VRR = 15.51 ± 0.11, a mean absolute V-magnitude of MV = 0.636 ± 0.053; and an effective temperature for RR0's and RR1's of log10Teff = 3.797 and log10Teff = 3.855, respectively. The multi-band photometry allowed us to determine the reddening of the cluster, E(B-V) = 0.342 ± 0.021, which resulted in a distance of D(kpc) = 5.91 ± 0.31 to NGC 4833.

Hemorheology and heart rate variability in patients with diabetes mellitus type 2.

PubMed

Velcheva, Irena; Damianov, Petar; Mantarova, Stefka; Antonova, Nadia

2011-01-01

Our study aimed to investigate the relationship between hemorheological parameters and heart rate variability (HRV) in patients with diabetes mellitus type 2. Hemorheological variables, including hematocrit (Ht), fibrinogen (Fib), whole blood (WBV) and plasma viscosity (PV) at shear rates of 0.0237 s(-1) to 128.5 s(-1) were examined in 20 patients with diabetes mellitus type 2 and in 10 control subjects. They all underwent non-invasive short-term monitoring of heart rate at rest and after passive head-up tilt. Measurement of the R-R intervals and calculation of the time domain parameters and the power spectral data were performed by our softwear, using fast Fourier transformation. Significant increase of Fib and WBV in the patients in comparison to controls was found within the range of shear rates 0.0237 s(-1) to 128.5 s(-1). In the diabetic patients parallel decrease of the total power (TP), the low frequency spectral power (LF) and of the mean RR and mild increase of the low frequency-high frequency ratio (LF/HF) at rest were established. This tendency was kept after the passive tilt. In patients with diabetes mellitus type 2 the increased blood viscosity was associated with reduced HRV.

Contribution of autonomic dysfunction to abnormal exercise blood pressure in type 2 diabetes mellitus.

PubMed

Weston, Kassia S; Sacre, Julian W; Jellis, Christine L; Coombes, Jeff S

2013-01-01

The purpose of this study was to compare the presence and severity of autonomic dysfunction in type 2 diabetes mellitus patients, with and without exaggerated blood pressure responses to exercise. We performed a cross-sectional analysis of 98 patients with type 2 diabetes mellitus (aged 59±9). Both time (standard deviation of RR intervals, root-mean-square of successive RR interval differences) and frequency (total spectral power, high frequency, low frequency, very low frequency) domains of heart rate variability were analysed in a 5 min recording at rest and 20 min after a maximal treadmill test. An exaggerated blood pressure response to exercise was identified by peak blood pressure ≥190/105 mmHg (women) or ≥210/105 mmHg (men). Each group of either exaggerated exercise blood pressure response or normal blood pressure response consisted of 49 patients. At rest there were no significant differences between groups for all time and frequency domain parameters of heart rate variability. Post-exercise, there was a significant (p<0.05) reduction in the SDNN, RMSSD and TP in the exaggerated exercise blood pressure group. Independent correlates (p<0.01) of exercise systolic blood pressure included post-exercise TP, resting systolic blood pressure, cardiac autonomic neuropathy and beta-blockers (beta=-0.28, adj. R² = 0.32, p<0.001). Reduced post-exercise heart rate variability in patients with type 2 diabetes mellitus, with an exaggerated exercise blood pressure response suggests preclinical autonomic dysfunction characterized by impaired vagal modulation. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Nocturnal heart rate variability in 1-year-old infants analyzed by using the Least Square Cosine Spectrum Method.

PubMed

Kochiya, Yuko; Hirabayashi, Akari; Ichimaru, Yuhei

2017-09-16

To evaluate the dynamic nature of nocturnal heart rate variability, RR intervals recorded with a wearable heart rate sensor were analyzed using the Least Square Cosine Spectrum Method. Six 1-year-old infants participated in the study. A wearable heart rate sensor was placed on their chest to measure RR intervals and 3-axis acceleration. Heartbeat time series were analyzed for every 30 s using the Least Square Cosine Spectrum Method, and an original parameter to quantify the regularity of respiratory-related heart rate rhythm was extracted and referred to as "RA (RA-COSPEC: Respiratory Area obtained by COSPEC)." The RA value is higher when a cosine curve is fitted to the original data series. The time sequential changes of RA showed cyclic changes with significant rhythm during the night. The mean cycle length of RA was 70 ± 15 min, which is shorter than young adult's cycle in our previous study. At the threshold level of RA greater than 3, the HR was significantly decreased compared with the RA value less than 3. The regularity of heart rate rhythm showed dynamic changes during the night in 1-year-old infants. Significant decrease of HR at the time of higher RA suggests the increase of parasympathetic activity. We suspect that the higher RA reflects the regular respiratory pattern during the night. This analysis system may be useful for quantitative assessment of regularity and dynamic changes of nocturnal heart rate variability in infants.

Effect of head-down-tilt bed rest and hypovolemia on dynamic regulation of heart rate and blood pressure

NASA Technical Reports Server (NTRS)

Iwasaki, K. I.; Zhang, R.; Zuckerman, J. H.; Pawelczyk, J. A.; Levine, B. D.; Blomqvist, C. G. (Principal Investigator)

2000-01-01

Adaptation to head-down-tilt bed rest leads to an apparent abnormality of baroreflex regulation of cardiac period. We hypothesized that this "deconditioning response" could primarily be a result of hypovolemia, rather than a unique adaptation of the autonomic nervous system to bed rest. To test this hypothesis, nine healthy subjects underwent 2 wk of -6 degrees head-down bed rest. One year later, five of these same subjects underwent acute hypovolemia with furosemide to produce the same reductions in plasma volume observed after bed rest. We took advantage of power spectral and transfer function analysis to examine the dynamic relationship between blood pressure (BP) and R-R interval. We found that 1) there were no significant differences between these two interventions with respect to changes in numerous cardiovascular indices, including cardiac filling pressures, arterial pressure, cardiac output, or stroke volume; 2) normalized high-frequency (0.15-0.25 Hz) power of R-R interval variability decreased significantly after both conditions, consistent with similar degrees of vagal withdrawal; 3) transfer function gain (BP to R-R interval), used as an index of arterial-cardiac baroreflex sensitivity, decreased significantly to a similar extent after both conditions in the high-frequency range; the gain also decreased similarly when expressed as BP to heart rate x stroke volume, which provides an index of the ability of the baroreflex to alter BP by modifying systemic flow; and 4) however, the low-frequency (0.05-0.15 Hz) power of systolic BP variability decreased after bed rest (-22%) compared with an increase (+155%) after acute hypovolemia, suggesting a differential response for the regulation of vascular resistance (interaction, P < 0.05). The similarity of changes in the reflex control of the circulation under both conditions is consistent with the hypothesis that reductions in plasma volume may be largely responsible for the observed changes in cardiac baroreflex control after bed rest. However, changes in vasomotor function associated with these two conditions may be different and may suggest a cardiovascular remodeling after bed rest.

Autonomic cardiovascular control recovery in quadriplegics after handcycle training.

PubMed

Abreu, Elizângela Márcia de Carvalho; Alves, Rani de Souza; Borges, Ana Carolina Lacerda; Lima, Fernanda Pupio Silva; Júnior, Alderico Rodrigues de Paula; Lima, Mário Oliveira

2016-07-01

The aim of this study was to investigate the cardiovascular autonomic acute response, during recovery after handcycle training, in quadriplegics with spinal cord injury (SCI). [Subjects and Methods] Seven quadriplegics (SCIG -level C6-C7, male, age 28.00 ± 6.97 years) and eight healthy subjects (CG -male, age 25.00 ± 7.38 years) were studied. Their heart rate variability (HRV) was assessed before and after one handcycle training. [Results] After the training, the SCIG showed significantly reduced: intervals between R waves of the electrocardiogram (RR), standard deviation of the NN intervals (SDNN), square root of the mean squares differences of sucessive NN intervals (rMSSD), low frequency power (LF), high frequency power (HF), and Poincaré plot (standard deviation of short-term HRV -SD1 and standard deviation of long-term HRV -SD2). The SDNN, LF, and SD2 remained decreased during the recovery time. The CG showed significantly reduced: RR, rMSSD, number of pairs of adjacent NN intervals differing by more than 50 ms (pNN50), LF, HF, SD1, and sample entropy (SampEn). Among these parameters, only RR remained decreased during recovery time. Comparisons of the means of HRV parameters evaluated between the CG and SCIG showed that the SCIG had significantly lower pNN50, LF, HF, and SampEn before training, while immediately after training, the SCIG had significantly lower SDNN, LF, HF, and SD2. The rMSSD30s of the SCIG significantly reduced in the windows 180 and 330 seconds and between the windows 300 seconds in the CG. [Conclusion] There was a reduction of sympathetic and parasympathetic activity in the recovery period after the training in both groups; however, the CG showed a higher HRV. The parasympathetic activity also gradually increased after training, and in the SCIG, this activity remained reduced even at three minutes after the end of training, which suggests a deficiency in parasympathetic reactivation in quadriplegics after SCI.

Neighborhood socioeconomic status and the prevalence of stroke and coronary heart disease in rural China: a population-based study

PubMed Central

Tang, Xun; Laskowitz, Daniel T.; He, Liu; Østbye, Truls; Bettger, Janet Prvu; Cao, Yang; Li, Na; Li, Jingrong; Zhang, Zongxin; Liu, Jianjiang; Yu, Liping; Xu, Haitao; Hu, Yonghua; Goldstein, Larry B.

2014-01-01

Background Lower neighborhood-level socioeconomic status (SES) is associated with an increased risk of vascular disease in developed countries. Aims This study aims to identify village- and individual-level determinants of stroke and coronary heart disease (CHD) in a rural Chinese population. Methods We analyzed data from a population-based survey of 14,424 rural Chinese adults aged over 40-years from 54 villages. Primary outcomes were stroke and CHD prevalence. Village-level SES was determined from the Chinese government's official statistical yearbook. Individual-level characteristics were obtained by in-person interviews. Prevalence rate ratios (RR) and 95% confidence intervals (95% CI) were calculated using generalized linear mixed models with log link function to explore associations of village-level SES and individual social, demographic, and cardiovascular risk factors with stroke or CHD. Variance was expressed using the median rate ratio (MRR) and interval rate ratio (IRR). Results Villages accounted for significant variability in the prevalence of stroke (MRR=1.70; 95% CI:1.42-1.94; P<0.05) and CHD (MRR=1.59; 95% CI:1.35-1.78, P<0.05) with village-level income alone accounted for 10% and 13.5% of between-village variation in stroke and CHD, respectively. High-income villages were at higher risk of both stroke (RR=1.69, 95% CI:1.09∼2.62) and CHD (RR=1.63, 95% CI:1.13∼2.34) than lower-income villages. Among individual-level risk factors, hypertension was associated with a higher prevalence of stroke (RR=2.33, 95% CI:1.93-2.80) than CHD (RR=1.58, 95% CI:1.38-1.82), whereas obesity was only associated with CHD (RR=1.43, 95% CI:1.23-1.66). In addition, there was an interaction between age and income; residents of higher income villages age<60 had a higher prevalence of CHD (RR=1.58, 95% CI:1.15-2.18), but not stroke. Conclusions There were differences in vascular risk across rural villages in China, with higher lifetime stroke and CHD prevalence in higher income villages. For CHD, neighborhood effects were stronger among younger residents of high-income villages. The results may have implications for public health interventions targeting populations at risk. PMID:25088683

Associations of Baroreflex Sensitivity, Heart Rate Variability, and Initial Orthostatic Hypotension with Prenatal and Recent Postnatal Methylmercury Exposure in the Seychelles Child Development Study at Age 19 Years

PubMed Central

Périard, Daniel; Beqiraj, Bujar; Hayoz, Daniel; Viswanathan, Bharathi; Evans, Katie; Thurston, Sally W.; Davidson, Philip W.; Myers, Gary J.; Bovet, Pascal

2015-01-01

Background: A few studies have suggested an association between prenatal exposure to methylmercury and decreased heart rate variability (HRV) related to autonomic heart function, but no study has examined this association using baroreflex sensitivity (BRS). In this study we assessed the distribution of BRS and immediate orthostatic hypotension (IOH) in young Seychellois adults and their associations with exposure to prenatal and recent postnatal methylmercury. Methods: Subjects in theSeychelles Child Development Study (SCDS) main cohort were evaluated at age 19 years. Non-invasive beat-to-beat blood pressure (BP) monitoring (Finapres, Ohmeda) was performed at rest and during active standing in 95 consecutive subjects. Recent postnatal mercury exposure was measured in subjects’ hair at the age of 19 years and prenatal exposure in maternal hair grown during pregnancy. BRS was estimated by sequence analysis to identify spontaneous ascending and descending BP ramps. HRV was estimated by the following markers: PNN50 (relative numbers of normal-to-normal intervals which are shorter by more than 50 ms than the immediately following normal-to-normal intervals); rMSSD (root mean of the squared sum of successive interval differences); LF/HF (low frequency/high frequency component ratio); ratio of the mean expiratory/inspiratory RR intervals (EI ratio); and the ratio between the longest RR interval 30 s after active standing and the shortest RR interval at 15 s (Max30/Min15). IOH was estimated by the deepest BP fall within the first 15 s after active standing up. Results: Prenatal MeHg exposures were similar in boys and girls (6.7 ± 4.3, 6.7 ± 3.8 ng/g) but recent postnatal mercury levels were higher in males than females (11.2 ± 5.8 vs 7.9 ± 4.3 ng/g, p = 0.003). Markers of autonomic heart rate control were within the normal range (BRS: 24.8 ± 7 ms/mm Hg, PNN50: 24.9 ± 6.8%, rMSSD: 68 ± 22, LF/HF: 0.61 ± 0.28) in both sexes. After standing, 51.4% of subjects had a transient systolic BP drop >40 mm Hg, but only 5.3% reported dizziness or had syncope. Prenatal and recent postnatal MeHg levels, overall, were not associated with BRS, E/I ratio, PNN50, rMSSD, LF/HF ratio, Max30/Min15 ratio, and IOH. Conclusions: This study provides no support for the hypothesis that prenatal or recent postnatal MeHg exposure from fish consumption is associated with impaired autonomic heart rate control. PMID:25807149

Associations of baroreflex sensitivity, heart rate variability, and initial orthostatic hypotension with prenatal and recent postnatal methylmercury exposure in the Seychelles Child Development Study at age 19 years.

PubMed

Périard, Daniel; Beqiraj, Bujar; Hayoz, Daniel; Viswanathan, Bharathi; Evans, Katie; Thurston, Sally W; Davidson, Philip W; Myers, Gary J; Bovet, Pascal

2015-03-23

A few studies have suggested an association between prenatal exposure to methylmercury and decreased heart rate variability (HRV) related to autonomic heart function, but no study has examined this association using baroreflex sensitivity (BRS). In this study we assessed the distribution of BRS and immediate orthostatic hypotension (IOH) in young Seychellois adults and their associations with exposure to prenatal and recent postnatal methylmercury. Subjects in the Seychelles Child Development Study (SCDS) main cohort were evaluated at age 19 years. Non-invasive beat-to-beat blood pressure (BP) monitoring (Finapres, Ohmeda) was performed at rest and during active standing in 95 consecutive subjects. Recent postnatal mercury exposure was measured in subjects' hair at the age of 19 years and prenatal exposure in maternal hair grown during pregnancy. BRS was estimated by sequence analysis to identify spontaneous ascending and descending BP ramps. HRV was estimated by the following markers: PNN50 (relative numbers of normal-to-normal intervals which are shorter by more than 50 ms than the immediately following normal-to-normal intervals); rMSSD (root mean of the squared sum of successive interval differences); LF/HF (low frequency/high frequency component ratio); ratio of the mean expiratory/inspiratory RR intervals (EI ratio); and the ratio between the longest RR interval 30 s after active standing and the shortest RR interval at 15 s (Max30/Min15). IOH was estimated by the deepest BP fall within the first 15 s after active standing up. Prenatal MeHg exposures were similar in boys and girls (6.7±4.3, 6.7±3.8 ng/g) but recent postnatal mercury levels were higher in males than females (11.2±5.8 vs 7.9±4.3 ng/g, p=0.003). Markers of autonomic heart rate control were within the normal range (BRS: 24.8±7 ms/mm Hg, PNN50: 24.9±6.8%, rMSSD: 68±22, LF/HF: 0.61±0.28) in both sexes. After standing, 51.4% of subjects had a transient systolic BP drop>40 mm Hg, but only 5.3% reported dizziness or had syncope. Prenatal and recent postnatal MeHg levels, overall, were not associated with BRS, E/I ratio, PNN50, rMSSD, LF/HF ratio, Max30/Min15 ratio, and IOH. This study provides no support for the hypothesis that prenatal or recent postnatal MeHg exposure from fish consumption is associated with impaired autonomic heart rate control.

Relevant Obstetric Factors for Cerebral Palsy: From the Nationwide Obstetric Compensation System in Japan

PubMed Central

Hasegawa, Junichi; Toyokawa, Satoshi; Ikenoue, Tsuyomu; Asano, Yuri; Satoh, Shoji; Ikeda, Tomoaki; Ichizuka, Kiyotake; Tamiya, Nanako; Nakai, Akihito; Fujimori, Keiya; Maeda, Tsugio; Masuzaki, Hideaki; Suzuki, Hideaki; Ueda, Shigeru

2016-01-01

Objective The aim of this study was to identify the relevant obstetric factors for cerebral palsy (CP) after 33 weeks’ gestation in Japan. Study design This retrospective case cohort study (1:100 cases and controls) used a Japanese national CP registry. Obstetric characteristics and clinical course were compared between CP cases in the Japan Obstetric Compensation System for Cerebral Palsy database and controls in the perinatal database of the Japan Society of Obstetrics and Gynecology born as live singleton infants between 2009 and 2011 with a birth weight ≥ 2,000 g and gestation ≥ 33 weeks. Results One hundred and seventy-five CP cases and 17,475 controls were assessed. Major relevant single factors for CP were placental abnormalities (31%), umbilical cord abnormalities (15%), maternal complications (10%), and neonatal complications (1%). A multivariate regression model demonstrated that obstetric variables associated with CP were acute delivery due to non-reassuring fetal status (relative risk [RR]: 37.182, 95% confidence interval [CI]: 20.028–69.032), uterine rupture (RR: 24.770, 95% CI: 6.006–102.160), placental abruption (RR: 20.891, 95% CI: 11.817–36.934), and preterm labor (RR: 3.153, 95% CI: 2.024–4.911), whereas protective factors were head presentation (RR: 0.199, 95% CI: 0.088–0.450) and elective cesarean section (RR: 0.236, 95% CI: 0.067–0.828). Conclusion CP after 33 weeks’ gestation in the recently reported cases in Japan was strongly associated with acute delivery due to non-reassuring fetal status, uterine rupture, and placental abruption. PMID:26821386

RR Lyrae variables in M33: two new fields and an analysis of the galaxy's population

NASA Astrophysics Data System (ADS)

Tanakul, Nahathai; Yang, Soung-Chul; Sarajedini, Ata

2017-06-01

We present a re-analysis of M33 RR Lyrae variables in four different fields: two inner disc fields and two outer disc fields. These are located at 8.5, 8.7, 36 and 46 arcmin from the centre of M33, respectively. We identify 48 new RR Lyrae variable stars and refine the light-curve properties of 51 previously identified variables. From the light curves, we calculate reddenings and metallicities for each star. Using data in this paper and previously published material, we are able to construct a radial density profile for the RR Lyrae stars in M33. This profile, when plotted in log space, has a slope of ˜-2.0 ± 0.15 which agrees with the radial distribution of halo stars in the Milky Way and M31. This suggests that the majority of M33 RR Lyrae variables observed so far belong to the halo. We also examine the RR Lyrae specific frequency and absolute magnitude relation in M33 and find good agreement with previous studies.

Cutoffs of Short-Term Heart Rate Variability Parameters in Brazilian Adolescents Male.

PubMed

Farah, Breno Quintella; Christofaro, Diego Giulliano Destro; Cavalcante, Bruno Remígio; Andrade-Lima, Aluísio; Germano-Soares, Antonio Henrique; Vanderlei, Luiz Carlos Marques; Lanza, Fernanda Cordoba; Ritti-Dias, Raphael Mendes

2018-05-15

A low heart rate variability (HRV) has been associated with cardiovascular risk factors in adolescents. However, no cut-off points are known for HRV parameters in this age group, making it difficult to use in clinical practice. Thus, the aims of the current study were to establish cutoffs of HRV parameters and to examine their association with cardiovascular risk in Brazilian adolescents male. For this reason, this cross-sectional study included 1152 adolescent boys (16.6 ± 1.2 years old). HRV measures of time (SD of all RR intervals, root mean square of the squared differences between adjacent normal RR intervals, and the percentage of adjacent intervals over 50 ms), frequency domains [low (LF) and high (HF) frequency], and Poincaré plot (SD1, SD2 and SD1/SD2 ratio) were assessed. Cardiovascular risk was assessed by sum of abdominal obesity, high blood pressure, overweight, and low physical activity level. The proposed cutoffs showed moderate to high sensitivity, specificity, and area under curve values (p < 0.05). HRV frequency parameters were statistically superior when compared to time-domain and Poincaré plot parameters. The binary logistic regression analysis indicated that all proposed HRV cutoffs were independently associated with a clustering of cardiovascular risk factors, with greater magnitude of HF and SD1/SD2 ratio (two or more risk factors: OR = 3.59 and 95% CI 1.76-7.34). In conclusion, proposed HRV cutoffs have moderate to high sensitivity in detecting of the cardiovascular risk factor and HRV frequency-domain were better discriminants of cardiovascular risk than time-domain and Poincaré plot parameters.

Heart rate variability is a predictor of mortality in chronic kidney disease: a report from the CRIC Study.

PubMed

Drawz, Paul E; Babineau, Denise C; Brecklin, Carolyn; He, Jiang; Kallem, Radhakrishna R; Soliman, Elsayed Z; Xie, Dawei; Appleby, Dina; Anderson, Amanda H; Rahman, Mahboob

2013-01-01

Low heart rate variability (HRV) is a risk factor for adverse outcomes in the general population. We aimed to determine the factors associated with HRV and evaluate the association between low HRV and clinical outcomes in patients with chronic kidney disease (CKD). A 10-second electrocardiogram was obtained at baseline in the Chronic Renal Insufficiency Cohort (CRIC) Study. HRV was measured by the standard deviation of all R-R intervals (SDNN) and the root mean square of successive differences between R-R intervals (RMSSD). In 3,245 CRIC participants with available baseline SDNN and RMSSD, lower HRV was associated with older age, lack of exercise, heart failure, elevated phosphorus and hemoglobin A1c, and low estimated glomerular filtration rate. After a median follow-up of 4.2 years, in fully adjusted models, lower HRV was not associated with renal [SDNN: hazard rate, HR = 0.96 (95% confidence interval, CI 0.88-1.05); RMSSD: HR = 0.97 (95% CI 0.88-1.07)] or cardiovascular outcomes [SDNN: HR = 1.02 (95% CI 0.92-1.13); RMSSD: HR = 1.00 (95% CI 0.90-1.10)]. There was a nonlinear relationship between RMSSD and all-cause mortality with increased risk with both low and high RMSSD (p = 0.04). In a large cohort of patients with CKD, multiple risk factors for renal and cardiovascular diseases were associated with lower HRV. Lower HRV was not associated with increased risk for renal or cardiovascular outcomes, but both low and high RMSSD were associated with increased risk for all-cause mortality. In conclusion, HRV measured by RMSSD may be a novel and independent risk factor for mortality in CKD patients. © 2013 S. Karger AG, Basel.

The role of wearable sensors and wireless technologies for the assessment of heart rate variability in anorexia nervosa.

PubMed

Billeci, Lucia; Tartarisco, Gennaro; Brunori, Elena; Crifaci, Giulia; Scardigli, Silvia; Balocchi, Rita; Pioggia, Giovanni; Maestro, Sandra; Morales, Maria Aurora

2015-03-01

Bradycardia and abnormal cardiac autonomic function are related to increased mortality in anorexia nervosa (AN). The aim of this study was to assess heart rate (HR) and HR variability of young adolescents with AN as compared to controls by means of wearable sensors and wireless technologies. The ECG signal was recorded in 27 AN girls and 15 healthy girls at rest using a wearable chest strap. The tachogram, the mean intervals between R peaks (meanRR), the root mean square of successive differences (RMSSD), the power of low-frequency (LF) and high-frequency (HF) bands and the LF/HF ratio were assessed. All AN girls showed a reduced HR and an increased meanRR and RMSSD. An HF increase, a LF decrease, and a LF/HF reduction indicated a prevalence of the parasympathetic on sympathetic activity. The instruments used in this pilot study were feasible, unobtrusive and extremely suitable in AN subjects who are burdened by high incidence of cardiovascular mortality; their application could open to new approaches of vital signs monitoring in hospitals as well as in home settings.

Association of Seasonal Climate Variability and Age-Specific Mortality in Northern Sweden before the Onset of Industrialization

PubMed Central

Rocklöv, Joacim; Edvinsson, Sören; Arnqvist, Per; de Luna, Sara Sjöstedt; Schumann, Barbara

2014-01-01

Background and aims: Little is known about health impacts of climate in pre-industrial societies. We used historical data to investigate the association of temperature and precipitation with total and age-specific mortality in Skellefteå, northern Sweden, between 1749 and 1859. Methods: We retrieved digitized aggregated population data of the Skellefteå parish, and monthly temperature and precipitation measures. A generalized linear model was established for year to year variability in deaths by annual and seasonal average temperature and cumulative precipitation using a negative binomial function, accounting for long-term trends in population size. The final full model included temperature and precipitation of all four seasons simultaneously. Relative risks (RR) with 95% confidence intervals (CI) were calculated for total, sex- and age-specific mortality. Results: In the full model, only autumn precipitation proved statistically significant (RR 1.02; CI 1.00–1.03, per 1cm increase of autumn precipitation), while winter temperature (RR 0.98; CI 0.95–1.00, per 1 °C increase in temperature) and spring precipitation (RR 0.98; CI 0.97–1.00 per 1 cm increase in precipitation) approached significance. Similar effects were observed for men and women. The impact of climate variability on mortality was strongest in children aged 3–9, and partly also in older children. Infants, on the other hand, appeared to be less affected by unfavourable climate conditions. Conclusions: In this pre-industrial rural region in northern Sweden, higher levels of rain during the autumn increased the annual number of deaths. Harvest quality might be one critical factor in the causal pathway, affecting nutritional status and susceptibility to infectious diseases. Autumn rain probably also contributed to the spread of air-borne diseases in crowded living conditions. Children beyond infancy appeared most vulnerable to climate impacts. PMID:25003551

RR Lyrae in the UMi dSph Galaxy

NASA Astrophysics Data System (ADS)

Kuehn, Charles; Kinemuchi, Karen; Jeffery, Elizabeth; Grabowski, Kathleen; Nemec, James; Herrera, Daniel

2018-01-01

Over the past two years we have obtained observations of the Ursa Minor dwarf spheroidal galaxy with the goal of completing an updated catalog of the variable stars in the dwarf galaxy. In addition to finding new variable stars, this updated catalog will allow us to look at period changes in the variables and to determine stellar characteristic for the RR Lyrae stars in the dSph. We will compare the RR Lyrae stellar characteristics to other RR Lyrae stars found in the Local Group dSph galaxies; these comparisons can give us insights to the near-field cosmology of the Local Group. In this poster we present our updated catalog of RR Lyrae stars in the UMi dSph; the updated catalog includes Fourier decomposition parameters, metallicities, and other physical properties for the RR Lyrae stars.

Association with meteo-climatological factors and daily emergency visits for renal colic and urinary calculi in Cuneo, Italy. A retrospective observational study, 2007-2010.

PubMed

Condemi, Vincenzo; Gestro, Massimo; Dozio, Elena; Tartaglino, Bruno; Corsi Romanelli, Massimiliano Marco; Solimene, Umberto; Meco, Roberto

2015-03-01

The incidence of nephrolithiasis is rising worldwide, especially in women and with increasing age. Incidence and prevalence of kidney stones are affected by genetic, nutritional, and environmental factors. The aim of this study is to investigate the link between various meteorological factors (independent variables) and the daily number of visits to the Emergency Department (ED of the S. Croce and Carle Hospital of Cuneo for renal colic (RC) and urinary stones (UC) as the dependent variable over the years 2007-2010.The Poisson generalized regression models (PGAMs) have been used in different progressive ways. The results of PGAMs (stage 1) adjusted for seasonal and calendar factors confirmed a significant correlation (p < 0.03) with the thermal parameter. Evaluation of the dose-response effect [PGAMs combined with distributed lags nonlinear models (DLNMs)-stage 2], expressed in terms of relative risk (RR) and cumulative relative risk (RRC), indicated a relative significant effect up to 15 lag days of lag (RR > 1), with a first peak after 5 days (lag ranges 0-1, 0-3, and 0-5) and a second weak peak observed along the 5-15 lag range days. The estimated RR for females was significant, mainly in the second and fourth age group considered (19-44 and >65 years): RR for total ED visits 1.27, confidence interval (CI) 1.11-1.46 (lag 0-5 days); RR 1.42, CI 1.01-2.01 (lag 0-10 days); and RR 1.35, CI 1.09-1.68 (lag 0-15 days). The research also indicated a moderate involvement of the thermal factor in the onset of RC caused by UC, exclusively in the female sex. Further studies will be necessary to confirm these results.

Fluctuations of healthy and unhealthy heartbeat intervals

NASA Astrophysics Data System (ADS)

Lan, Boon Leong; Toda, Mikito

2013-04-01

We show that the RR-interval fluctuations, defined as the difference between successive natural-logarithm of the RR interval, for healthy, congestive-heart-failure (CHF) and atrial-fibrillation (AF) subjects are well modeled by non-Gaussian stable distributions. Our results suggest that healthy or unhealthy RR-interval fluctuation can generally be modeled as a sum of a large number of independent physiological effects which are identically distributed with infinite variance. Furthermore, we show for the first time that one indicator —the scale parameter of the stable distribution— is sufficient to robustly distinguish the three groups of subjects. The scale parameters for healthy subjects are smaller than those for AF subjects but larger than those for CHF subjects —this ordering suggests that the scale parameter could be used to objectively quantify the severity of CHF and AF over time and also serve as an early warning signal for a healthy person when it approaches either boundary of the healthy range.

Facial Video-Based Photoplethysmography to Detect HRV at Rest.

PubMed

Moreno, J; Ramos-Castro, J; Movellan, J; Parrado, E; Rodas, G; Capdevila, L

2015-06-01

Our aim is to demonstrate the usefulness of photoplethysmography (PPG) for analyzing heart rate variability (HRV) using a standard 5-min test at rest with paced breathing, comparing the results with real RR intervals and testing supine and sitting positions. Simultaneous recordings of R-R intervals were conducted with a Polar system and a non-contact PPG, based on facial video recording on 20 individuals. Data analysis and editing were performed with individually designated software for each instrument. Agreement on HRV parameters was assessed with concordance correlations, effect size from ANOVA and Bland and Altman plots. For supine position, differences between video and Polar systems showed a small effect size in most HRV parameters. For sitting position, these differences showed a moderate effect size in most HRV parameters. A new procedure, based on the pixels that contained more heart beat information, is proposed for improving the signal-to-noise ratio in the PPG video signal. Results were acceptable in both positions but better in the supine position. Our approach could be relevant for applications that require monitoring of stress or cardio-respiratory health, such as effort/recuperation states in sports. © Georg Thieme Verlag KG Stuttgart · New York.

Extracting stationary segments from non-stationary synthetic and cardiac signals

NASA Astrophysics Data System (ADS)

Rodríguez, María. G.; Ledezma, Carlos A.; Perpiñán, Gilberto; Wong, Sara; Altuve, Miguel

2015-01-01

Physiological signals are commonly the result of complex interactions between systems and organs, these interactions lead to signals that exhibit a non-stationary behaviour. For cardiac signals, non-stationary heart rate variability (HRV) may produce misinterpretations. A previous work proposed to divide a non-stationary signal into stationary segments by looking for changes in the signal's properties related to changes in the mean of the signal. In this paper, we extract stationary segments from non-stationary synthetic and cardiac signals. For synthetic signals with different signal-to-noise ratio levels, we detect the beginning and end of the stationary segments and the result is compared to the known values of the occurrence of these events. For cardiac signals, RR interval (cardiac cycle length) time series, obtained from electrocardiographic records during stress tests for two populations (diabetic patients with cardiovascular autonomic neuropathy and control subjects), were divided into stationary segments. Results on synthetic signals reveal that the non-stationary sequence is divided into more stationary segments than needed. Additionally, due to HRV reduction and exercise intolerance reported on diabetic cardiovascular autonomic neuropathy patients, non-stationary RR interval sequences from these subjects can be divided into longer stationary segments compared to the control group.

Effects of Nitrate Supplementation on Cardiovascular and Autonomic Reactivity in African-American Females

PubMed Central

Bond, Vernon; Curry, Bryan H.; Adams, R. George; Asadi, M. Sadegh; Stancil, Kimani A.; Millis, Richard M.; Haddad, Georges E.

2014-01-01

Previous studies have shown that beetroot juice (BJ) decreases systolic blood pressure (SBP) and oxygen demand. This study tests the hypothesis that a beetroot juice (BJ) treatment increases heart rate variability (HRV) measured by the average standard deviation of normal-normal electrocardiogram RR intervals (SDNN) and the low frequency (LF), mainly sympathetic, fast Fourier transform spectral index of HRV. The subjects were 13 healthy young adult African-American females. Placebo control orange juice (OJ) and BJ treatments were given on separate days. Blood nitric oxide [NO], SBP and RR intervals were measured at rest and at constant workloads set to 40% and 80% of the predetermined VO2peak. Two hours after ingestion the BJ treatment increased [NO] and decreased SBP. BJ also increased SDNN at rest and at the 40% VO2peak workload, without significant effects on LF. SDNN was significantly greater after the BJ than after the OJ treatment, across the two physical activity conditions and SDNN was (negatively) correlated with SBP. These results suggest that BJ decreases SBP and increases HRV at rest and during aerobic exercise. Similar results in subjects with prehypertension or hypertension could translate to a dietary nitrate treatment for hypertension. PMID:25401100

The safety assessment of saffron (Crocus sativus L.) on sympathovagal balance and heart rate variability; a comparison with amiodarone.

PubMed

Joukar, Siyavash; Dehesh, Mohammad-Moein

2015-12-01

Dry stigmas of the Crocus sativus L. (Saffron) are well known in world as a popular flavouring and therapeutic agent. The anxiolytic, antidepressant, anticonvulsant and antiarrhythmic effects of saffron suggest that it may affect the autonomic control of the heart. This study assessed its safety on cardiac sympathovagal balance and heart rate variability in rat. Experimental groups were control, Saf50, Saf100, Saf200 (received saffron at dosages of 50 and 100 and 200 mg/kg/d, orally, respectively) and Amio (received 30 mg/mL/kg/d of amiodarone, orally, for 7 days) groups. On day 8, the frequency domain and time domain indices of animals' electrocardiograms were calculated. The heart rate decreased and RR interval increased in Saf200 and Amio groups (P<.05 vs other groups). Square root of the mean squared differences of successive RR intervals enhanced in all treated groups, however, was only significant in Amio group (P<.05). The SD1/SD2 ratio was higher in Saf200 and Amio groups. Both low-frequency (LF) and high-frequency (HF) parameters were higher, and the LF/HF ratio was non-significantly lower in treated groups. The findings suggest that saffron not only has no harmful effect on activity of cardiac autonomic nervous system, but it may improve the stability of heart sympathovagal balance in normal rat. © 2016 John Wiley & Sons Ltd.

Scatterplot analysis of EEG slow-wave magnitude and heart rate variability: an integrative exploration of cerebral cortical and autonomic functions.

PubMed

Kuo, Terry B J; Yang, Cheryl C H

2004-06-15

To explore interactions between cerebral cortical and autonomic functions in different sleep-wake states. Active waking (AW), quiet sleep (QS), and paradoxical sleep (PS) of adult male Wistar-Kyoto rats (WKY) on their daytime sleep were compared. Ten WKY. All rats had electrodes implanted for polygraphic recordings. One week later, a 6-hour daytime sleep-wakefulness recording session was performed. A scatterplot analysis of electroencephalogram (EEG) slow-wave magnitude (0.5-4 Hz) and heart rate variability (HRV) was applied in each rat. The EEG slow-wave-RR interval scatterplot from all of the recordings revealed a propeller-like pattern. If the scatterplot was divided into AW, PS, and QS according to the corresponding EEG mean power frequency and nuchal electromyogram, the EEG slow wave-RR interval relationship became nil, negative, and positive for AW, PS, and QS, respectively. A significant negative relationship was found for EEG slow-wave and high-frequency power of HRV (HF) coupling during PS and for EEG slow wave and low-frequency power of HRV to HF ratio (LF/HF) coupling during QS. The optimal time lags for the slow wave-LF/HF relationship were different between PS and QS. Bradycardia noted in QS and PS was related to sympathetic suppression and vagal excitation, respectively. The EEG slow wave-HRV scatterplot may provide unique insights into studies of sleep, and such a relationship may delineate the sleep-state-dependent fluctuations in autonomic nervous system activity.

Contributions of tidal lung inflation to human R-R interval and arterial pressure fluctuations

NASA Technical Reports Server (NTRS)

Koh, J.; Brown, T. E.; Beightol, L. A.; Eckberg, D. L.

1998-01-01

We studied the effects of mechanical lung inflation on respiratory frequency R-R interval and arterial pressure fluctuations in nine healthy young adults undergoing elective orthopedic surgery. We conducted this research to define the contribution of pulmonary and thoracic stretch receptor input to respiratory sinus arrhythmia. We compared fast Fourier transform spectral power during three modes of ventilation: (1) spontaneous, frequency-controlled (0.25 Hz) breathing, (2) intermittent positive pressure ventilation (0.25 Hz, with a tidal volume of 8 ml/kg) and (3) high frequency jet ventilation (5.0 Hz, 2.5 kg/cm2), after sedation and vecuronium paralysis. Mean R-R intervals, arterial pressures and arterial blood gas levels were comparable during all three breathing conditions. Respiratory frequency systolic pressure spectral power was comparable during spontaneous breathing and conventional mechanical ventilation, but was significantly reduced during high frequency jet ventilation (P < 0.05). Respiratory frequency R-R interval spectral power (used as an index of respiratory sinus arrhythmia) declined dramatically with sedation and muscle paralysis (P < 0.05), but was greater during conventional mechanical, than high frequency jet ventilation (P < 0.05). These results suggest that although phasic inputs from pulmonary and thoracic stretch receptors make a statistically significant contribution to respiratory sinus arrhythmia, that contribution is small.

Heart rate variability (HRV) analysis in radio and TV broadcasting stations workers.

PubMed

Bortkiewicz, Alicja; Gadzicka, Elżbieta; Szymczak, Wiesław; Zmyślony, Marek

2012-09-01

The aim of the study was to assess the mechanism of cardiovascular impairments in workers exposed to UHF-VHF radio frequency electromagnetic fields (EMF). Heart rate variability (HRV) was analysed using 512 normal heart beats registered at rest. The analysis concerned time-domain (STD R-R) and frequency-domain (VLF, LF, HF) parameters of HRV. Fifty nine workers (group I) with low-level and 12 workers (group II) with high-level exposure were examined. The mean age of the subjects was 47 ± 9 years and 41 ± 14 years, and mean exposure duration 19.1 ± 8.8 years and 13 ± 4 years, in groups I and II, respectively. The groups were divided according to: E(max), E(dose), E(mean) for frequencies UHF, VHF and UHF+VHF: The control group consisted of 42 non-exposed subjects, aged 49 ± 8 years. Statistical analysis comprised one-way analysis of variance, covariance analysis and logistic regression models. In the exposed groups, the heart rate was higher than in the control one. Standard deviation of R-R intervals (STD R-R) was found to be significantly (p = 0.0285) lower in group I (42.5 ± 24.7 ms) compared to the control group (62.9 ± 53.5 ms). The risk of lowered STD R-R was significantly increased (OR = 2.37, p = 0.023) in group II. Both exposed groups presented significantly higher VLF and LF values than the control group (p = 0.005 and p = 0.0025, respectively). The EMF-exposed groups were characterised by the dominance of the sympathetic system (LF/HF 1.3 ± 0.35). The results indicate that exposure to radiofrequency EMF may affect the neurovegetative regulation.

Musculoskeletal Injuries Among Female Soldiers Working With Dogs.

PubMed

Schermann, Haggai; Karakis, Isabella; Ankory, Ran; Kadar, Assaf; Yoffe, Victoria; Shlaifer, Amir; Yanovich, Ran

2018-05-18

Female soldiers serving in the Israeli Defense Forces canine unit may be at increased risk of overuse injuries related to working with military dogs. We hypothesized that this particular type of occupational exposure may lead to an increased strain of the upper extremity due to such non-physiologic motions as pulling the dog's strap or resisting the sudden pulling by the dog, and may result in an increased rate of overuse injuries. We compared incidence of overuse injuries in a retrospective cohort of female soldiers who served either in the military working dogs' unit (MWD), or in the light infantry battalions (Infantry) from 2005 to 2015. We compared injury incidence of both groups during two periods: 5 mo of basic training (neither worked with dogs) and 19 or more months of combat service. Incidence was calculated as number of diagnoses per person-months (rate ratios, RR); each diagnosis counted once per study subject. We used RR confidence intervals to compare incidence of injuries between groups. There were 3,443 person-months in the MWD group and 194,590 person-months in the Infantry group. There was no difference in injury incidence between groups during the initial period of basic training. During the second period, MWDs had higher incidence of upper limb (RR = 1.45, p = 0.048) and hip (RR = 3.6, p < 0.0001) injuries. The association between service with dogs and upper limb injuries remained significant (RR = 1.09, p = 0.005) after adjusting for confounding variables in the multivariate regression analysis. Other independent predictors of the upper limb overuse injuries included each additional month of service (RR = 1.003, p = 0.008), Eastern European origin compared with Israeli-born recruits (RR = 0.97, p = 0.03), increased body weight in increments of 10 kg (RR = 1.008, p = 0.03), anemia (RR = 1.02, p = 0.02) and fatigue (RR = 1.05, p ≤ 0.0001). We found that service in the MWD unit was associated with increased risk of upper limb injuries. Identification of the exact mechanism of injury and targeted interventions, as well as treatment of anemia and fatigue may lead to reduction of injuries in this unit.

Heart rate variabilty changes during first week of acclimatization to 3500 m altitude in Indian military personnel.

PubMed

Bhaumik, G; Dass, D; Bhattacharyya, D; Sharma, Y K; Singh, S B

2013-01-01

Acute exposure to hypobaric hypoxia induces the changes in autonomic control of heart rate. Due to emergencies or war like conditions, rapid deployment of Indian military personnel into high altitude frequently occurs. Rapid deployment to high altitude soldiers are at risk of developing high altitude sickness. The present study was conducted to evaluate the acute exposure to high altitude hypobaric hypoxia (3500 m altitude) on the autonomic nervous control of heart rate in Indian military personnel during first week of acclimatization Indices of heart rate variability (viz; R-R interval, total power, low frequency, high frequency, ratio of low to high frequency) and pulse arterial oxygen saturation were measured at sea level and 3500m altitude. Power spectrum of heart rate variability was quantified by low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.5 Hz) widths. The ratio of LF to HF was also assessed as an index of the sympathovagal balance. Mean R-R interval decreased significantly on day 2 on induction to altitude which tended to increase on day 5. Total power (TP) decreased high altitude and tended to recover within a week. Both HF and LF power showed decrement at 3500m in comparison to sea level. The ratio of LF to HF (LF/HF) at 3500m was significantly higher at 3500m. SpO2 values decreased significantly (P < 0.05) at high altitude on day-2 which increased on day-5. We conclude that autonomic control of the heart rate measured by heart rate variability was altered on acute induction to 3500m which showed a significant decrease in parasympathetic tone and increase in sympathetic tone, then acclimatization seems to be characterized by progressive shift toward a higher parasympathetic tone.

Validation of Cardiovascular Parameters During NASA's Functional Task Test

NASA Technical Reports Server (NTRS)

Arzeno, N. M.; Stenger, M. B.; Bloomberg, J. J.; Platts, Steven H.

2008-01-01

Microgravity-induced physiological changes, including cardiovascular deconditioning may impair crewmembers f capabilities during exploration missions on the Moon and Mars. The Functional Task Test (FTT), which will be used to assess task performance in short and long duration astronauts, consists of 7 functional tests to evaluate crewmembers f ability to perform activities to be conducted in a partial-gravity environment or following an emergency landing on Earth. The Recovery from Fall/Stand Test (RFST) tests both the subject fs ability to get up from a prone position and orthostatic intolerance. PURPOSE: Crewmembers have never become presyncopal in the first 3 min of quiet stand, yet it is unknown whether 3 min is long enough to cause similar heart rate fluctuations to a 5-min stand. The purpose of this study was to validate and test the reliability of heart rate variability (HRV) analysis of a 3-min quiet stand. METHODS: To determine the validity of using 3 vs. 5-min of standing to assess HRV, 7 healthy subjects remained in a prone position for 2 min, stood up quickly and stood quietly for 6 min. ECG and continuous blood pressure data were recorded. Mean R-R interval and spectral HRV were measured in minutes 0-3 and 0-5 following the heart rate transient due to standing. Significant differences between the segments were determined by a paired t-test. To determine the reliability of the 3-min stand test, 13 healthy subjects completed 3 trials of the complete FTT on separate days, including the RFST with a 3-min stand test. Analysis of variance (ANOVA) was performed on the HRV measures. RESULTS: Spectral HRV measures reflecting autonomic activity were not different (p>0.05) during the 0-3 and 0-5 min segment (mean R-R interval: 738+/-74 ms, 728+/-69 ms; low frequency to high frequency ratio: 6.5+/-2.2, 7.7+/-2.7; normalized high frequency: 0.19+/-0.03, 0.18+/-0.04). The average coefficient of variation for mean R-R interval, systolic and diastolic blood pressures in the prone position and stand test were less than 8% for the test sessions. ANOVA results yielded a greater inter-subject variability (p.0.006) than inter-session variability (p>0.05) for HRV in the stand test. CONCLUSION: These studies show that a 3 minute stand delivers repeatable cardiovascular heart rate and BP data in the context of this larger series of tests such as the FTT.

Hypertension, antihypertensive medication and risk of renal carcinoma in California Seventh-Day Adventists.

PubMed

Fraser, G E; Phillips, R L; Beeson, W L

1990-12-01

A longitudinal study of 34 198 non-Hispanic white California Seventh-day Adventists identified incident cases of renal carcinoma over six years of follow-up. The use of antihypertensive medications and self-reported hypertension had estimated age-sex adjusted incidence rate ratios of 4.51 and 2.90 respectively. These were relatively unchanged by stratifying on additional variables that may have been confounders. Cases diagnosed later during the follow-up period had the strongest association with hypertension, making the alternative explanation that the cancer may have caused the hypertension less likely. Being married in 1976 (amongst females at least) was also associated with a marked elevation of risk. Point estimates of effect suggested that frequent (greater than or equal to 3 week) consumption of fruit (RR = 0.21) and salad vegetables (RR = 0.34) may be protective for this cancer, although the 95% confidence interval did not quite exclude the null value.

Evaluation of autonomic functions of patients with multiple system atrophy and Parkinson's disease by head-up tilt test.

PubMed

Watano, Chikako; Shiota, Yuri; Onoda, Keiichi; Sheikh, Abdullah Md; Mishima, Seiji; Nitta, Eri; Yano, Shozo; Yamaguchi, Shuhei; Nagai, Atsushi

2018-02-01

The aim of this study was to evaluate the autonomic neural function in Parkinson's disease (PD) and multiple system atrophy (MSA) with head-up tilt test and spectral analysis of cardiovascular parameters. This study included 15 patients with MSA, 15 patients with PD, and 29 healthy control (HC) subjects. High frequency power of the RR interval (RR-HF), the ratio of low frequency power of RR interval to RR-HF (RR-LF/HF) and LF power of systolic BP were used to evaluate parasympathetic, cardiac sympathetic and vasomotor sympathetic functions, respectively. Both patients with PD and MSA showed orthostatic hypotension and lower parasympathetic function (RR-HF) at tilt position as compared to HC subjects. Cardiac sympathetic function (RR-LF/HF) was significantly high in patients with PD than MSA at supine position. RR-LF/HF tended to increase in MSA and HC, but decreased in PD by tilting. Consequently, the change of the ratio due to tilting (ΔRR-LF/HF) was significantly lower in patients with PD than in HC subjects. Further analysis showed that compared to mild stage of PD, RR-LF/HF at the supine position was significantly higher in advanced stage. By tilting, it was increased in mild stage and decreased in the advanced stage of PD, causing ΔRR-LF/HF to decrease significantly in the advanced stage. Thus, we demonstrated that spectral analysis of cardiovascular parameters is useful to identify sympathetic and parasympathetic disorders in MSA and PD. High cardiac sympathetic function at the supine position, and its reduction by tilting might be a characteristic feature of PD, especially in the advanced stage.

Can we improve the clinical utility of respiratory rate as a monitored vital sign?

PubMed

Chen, Liangyou; Reisner, Andrew T; Gribok, Andrei; McKenna, Thomas M; Reifman, Jaques

2009-06-01

Respiratory rate (RR) is a basic vital sign, measured and monitored throughout a wide spectrum of health care settings, although RR is historically difficult to measure in a reliable fashion. We explore an automated method that computes RR only during intervals of clean, regular, and consistent respiration and investigate its diagnostic use in a retrospective analysis of prehospital trauma casualties. At least 5 s of basic vital signs, including heart rate, RR, and systolic, diastolic, and mean arterial blood pressures, were continuously collected from 326 spontaneously breathing trauma casualties during helicopter transport to a level I trauma center. "Reliable" RR data were identified retrospectively using automated algorithms. The diagnostic performances of reliable versus standard RR were evaluated by calculation of the receiver operating characteristic curves using the maximum-likelihood method and comparison of the summary areas under the receiver operating characteristic curves (AUCs). Respiratory rate shows significant data-reliability differences. For identifying prehospital casualties who subsequently receive a respiratory intervention (hospital intubation or tube thoracotomy), standard RR yields an AUC of 0.59 (95% confidence interval, 0.48-0.69), whereas reliable RR yields an AUC of 0.67 (0.57-0.77), P < 0.05. For identifying casualties subsequently diagnosed with a major hemorrhagic injury and requiring blood transfusion, standard RR yields an AUC of 0.60 (0.49-0.70), whereas reliable RR yields 0.77 (0.67-0.85), P < 0.001. Reliable RR, as determined by an automated algorithm, is a useful parameter for the diagnosis of respiratory pathology and major hemorrhage in a trauma population. It may be a useful input to a wide variety of clinical scores and automated decision-support algorithms.

The effect of post-exercise hydrotherapy on subsequent exercise performance and heart rate variability.

PubMed

Stanley, Jamie; Buchheit, Martin; Peake, Jonathan M

2012-03-01

We investigated the effect of hydrotherapy on time-trial performance and cardiac parasympathetic reactivation during recovery from intense training. On three occasions, 18 well-trained cyclists completed 60 min high-intensity cycling, followed 20 min later by one of three 10-min recovery interventions: passive rest (PAS), cold water immersion (CWI), or contrast water immersion (CWT). The cyclists then rested quietly for 160 min with R-R intervals and perceptions of recovery recorded every 30 min. Cardiac parasympathetic activity was evaluated using the natural logarithm of the square root of mean squared differences of successive R-R intervals (ln rMSSD). Finally, the cyclists completed a work-based cycling time trial. Effects were examined using magnitude-based inferences. Differences in time-trial performance between the three trials were trivial. Compared with PAS, general fatigue was very likely lower for CWI (difference [90% confidence limits; -12% (-18; -5)]) and CWT [-11% (-19; -2)]. Leg soreness was almost certainly lower following CWI [-22% (-30; -14)] and CWT [-27% (-37; -15)]. The change in mean ln rMSSD following the recovery interventions (ln rMSSD(Post-interv)) was almost certainly higher following CWI [16.0% (10.4; 23.2)] and very likely higher following CWT [12.5% (5.5; 20.0)] compared with PAS, and possibly higher following CWI [3.7% (-0.9; 8.4)] compared with CWT. The correlations between performance, ln rMSSD(Post-interv) and perceptions of recovery were unclear. A moderate correlation was observed between ln rMSSD(Post-interv) and leg soreness [r = -0.50 (-0.66; -0.29)]. Although the effects of CWI and CWT on performance were trivial, the beneficial effects on perceptions of recovery support the use of these recovery strategies.

The Influence of Interpregnancy Interval on Infant Mortality

PubMed Central

MCKINNEY, David; HOUSE, Melissa; CHEN, Aimin; MUGLIA, Louis; DEFRANCO, Emily

2017-01-01

Background In Ohio the infant mortality rate is above the national average and the black infant mortality rate is more than twice the white infant mortality rate. Having a short interpregnancy interval has been shown to correlate with preterm birth and low birth weight, but the effect of short interpregnancy interval on infant mortality is less well established. Objective To quantify the population impact of interpregnancy interval on the risk of infant mortality. Study Design This was a statewide population-based retrospective cohort study of all births (n=1,131,070) and infant mortalities (n=8,152) using linked Ohio birth and infant death records from 1/2007 through 9/2014. For this study we analyzed 5 interpregnancy interval categories: 0 to < 6 months, 6 to < 12 months, 12 to < 24 months, 24 to < 60 months, and ≥ 60 months. The primary outcome for this study was infant mortality. During the study period, 3701 infant mortalities were linked to a live birth certificate with an interpregnancy interval available. We calculated the frequency and relative risk (RR) of infant mortality for each interval compared to a referent interval of 12 to < 24 months. Stratified analyses by maternal race were also performed. Adjusted risks were estimated after accounting for statistically significant and biologically plausible confounding variables. Adjusted relative risk was utilized to calculate the attributable risk percent of short interpregnancy intervals on infant mortality. Results Short interpregnancy intervals were common in Ohio during the study period. 20.5% of all multiparous births followed an interval of < 12 months. The overall infant mortality rate during this time was 7.2 per 1000 live births (6.0 for white mothers and 13.1 for black mothers). Infant mortalities occurred more frequently for births that occurred following short intervals of 0 to < 6 months (9.2 per 1000) and 6 to < 12 months (7.1 per 1000) compared to 12 to < 24 months (5.6 per 1000), (p= <0.001 and <0.001). The highest risk for infant mortality followed interpregnancy intervals of 0 to < 6 months, adjRR 1.32 (95% CI 1.17–1.49) followed by interpregnancy intervals of 6 to < 12 months, adjRR 1.16 (95% CI 1.04–1.30). Analysis stratified by maternal race revealed similar findings. Attributable risk calculation showed that 24.2% of infant mortalities following intervals of 0 to < 6 months and 14.1% with intervals of 6 to < 12 months are attributable to the short interpregnancy interval. By avoiding short interpregnancy intervals of 12 months or less we estimate that in the state of Ohio 31 infant mortalities (20 white and 8 black) per year could have been prevented and the infant mortality rate could have been reduced from 7.2 to 7.0 during this time frame. Conclusion An interpregnancy interval of 12–60 months (1–5 years) between birth and conception of next pregnancy is associated with lowest risk of infant mortality. Public health initiatives and provider counseling to optimize birth spacing has the potential to significantly reduce infant mortality for both white and black mothers. PMID:28034653

Early Post-Operative Outcomes and Blood Product Utilization in Adult Cardiac Surgery- The Post Aprotinin Era

PubMed Central

DeSantis, Stacia; Toole, J. Matthew; Kratz, John M.; Uber, Walter E.; Wheat, Margaret J.; Stroud, Martha R.; Ikonomidis, John S.; Spinale, Francis G.

2011-01-01

Background Aprotinin was a commonly utilized pharmacological agent for homeostasis in cardiac surgery but was discontinued resulting in the extensive use of lysine analogues. This study tested the hypothesis that early post-operative adverse events and blood product utilization would affected in this post-aprotinin era. Methods/Results Adult patients (n=781) undergoing coronary artery bypass (CABG), valve replacement, or both from November 1, 2005-October 31, 2008 at a single institution were included. Multiple logistic regression modeling and propensity scoring were performed on 29 pre-operative and intra-operative variables in patients receiving aprotinin (n=325) or lysine analogues (n=456). The propensity adjusted relative risk (RR;95% confidence interval;CI) for the intra-operative use of packed red blood cells (RR:0.75;CI:0.57–0.99), fresh frozen plasma (RR:0.37;0.21–0.64), and cryoprecipitate (RR:0.06;CI:0.02–0.22) were lower in the aprotinin versus lysine analogue group (all p<0.05). The risk for mortality (RR:0.53;CI:0.16–1.79) and neurological events (RR:0.87;CI:0.35–2.18) remained similar between groups, whereas a trend for reduced risk for renal dysfunction was observed in the aprotinin group. Conclusions In the post-aprotinin era with the exclusive use of lysine analogues, the relative risk of early post-operative outcomes such as mortality and renal dysfunction have not improved, but the risk for the intra-operative use of blood products has increased. Thus, improvements in early post-operative outcomes have not been realized with the discontinued use of aprotinin, but rather increased blood product utilization has occurred with the attendant costs and risks inherent with this strategy. PMID:21911820

Beat-to-beat estimation of LVET and QS2 indices of cardiac mechanics from wearable seismocardiography in ambulant subjects.

PubMed

Di Rienzo, Marco; Vaini, Emanuele; Castiglioni, Paolo; Meriggi, Paolo; Rizzo, Francesco

2013-01-01

Seismocardiogram (SCG) is the measure of the minute vibrations produced by the beating heart. We previously demonstrated that SCG, ECG and respiration could be recorded over the 24 h during spontaneous behavior by a smart garment, the MagIC-SCG system. In the present case study we explored the feasibility of a beat-to-beat estimation of two indices of heart contractility, the Left Ventricular Ejection Time (LVET) and the electromechanical systole (QS2) from SCG and ECG recordings obtained by the MagIC-SCG device in one subject. We considered data collected during outdoor spontaneous behavior (while sitting in the metro and in the office) and in a laboratory setting (in supine and sitting posture, and during recovery after 100 W and 140 W cycling). LVET was estimated from SCG as the time interval between the opening and closure of the aortic valve, QS2 as the time interval between the Q wave of the ECG and the closure of the aortic valve. In every condition, LVET and QS2 could be estimated on a beat-to-beat basis from the SCG collected by the smart garment. LVET and QS2 are characterized by important beat-to-beat fluctuations, with standard deviations in the same order of magnitude of RR Interval. In all settings, spectral profiles are different for LVET, QS2 and RR Interval. This suggests that the biological mechanisms impinging on the heart exert a differentiated influence on the variability of each of these three indices.

An outbreak of cardiovascular syndromes requiring urgent medical treatment and its association with environmental factors: an ecological study

PubMed Central

Turner, Robin M; Muscatello, David J; Zheng, Wei; Willmore, Alan; Arendts, Glenn

2007-01-01

Background In April 2005, syndromic surveillance based on statistical control chart methods in Sydney, Australia, signalled increasing incidence of urgent emergency department visits for cardiovascular and chest pain syndromes compared to the preceding twelve months. This paper aimed to determine whether environmental factors could have been responsible for this 'outbreak'. Methods The outcome studied was daily counts of emergency department visits for cardiovascular or chest pain syndromes that were considered immediately or imminently life threatening on arrival at hospital. The outbreak had a mean daily count of 5.7 visits sustained for eight weeks, compared with 4.0 in the same months in previous years. Poisson regression was used to systematically assess the emergency department visits in relation to available daily weather and pollution variables by first finding the best model that explained short-term variation in the outcome over the period 25 January 2002 to 31 May 2005, and then assessing interactions of all available variables with the 'outbreak' period, April-May 2005. Rate ratios were estimated for an interquartile increase in each variable meaning that the ratio measures the relative increase (or decrease) in the emergency department visits for an interquartile increase in the weather or pollution variable. The rate ratios for the outbreak period measure the relative increase (or decrease) in the emergency department visits for an interquartile increase in the weather or pollution variable during the outbreak period only. Results The best fitting model over the whole study period included minimum temperature with a rate ratio (RR) of 0.86 (95% confidence interval (CI), 0.77–0.96), maximum relative humidity of 1.09 (95% CI 1.05–1.14) and minimum daily particulate matter less than 10 microns (PM10) of 1.05 (95% CI, 1.01–1.09). During the outbreak period, maximum temperature (RR 1.27, 95% CI 1.03–1.57), solar radiation (RR 1.44, 95% CI, 1.00–2.07) and ozone (RR 1.13, 95% CI 1.01–1.26) were associated with the outcome. Conclusion The increase may have been associated with photochemical pollution. Syndromic surveillance can identify outbreaks of non-communicable diseases associated with environmental factors. PMID:18036253

Analysis of Observational Studies in the Presence of Treatment Selection Bias: Effects of Invasive Cardiac Management on AMI Survival Using Propensity Score and Instrumental Variable Methods

PubMed Central

Stukel, Thérèse A.; Fisher, Elliott S; Wennberg, David E.; Alter, David A.; Gottlieb, Daniel J.; Vermeulen, Marian J.

2007-01-01

Context Comparisons of outcomes between patients treated and untreated in observational studies may be biased due to differences in patient prognosis between groups, often because of unobserved treatment selection biases. Objective To compare 4 analytic methods for removing the effects of selection bias in observational studies: multivariable model risk adjustment, propensity score risk adjustment, propensity-based matching, and instrumental variable analysis. Design, Setting, and Patients A national cohort of 122 124 patients who were elderly (aged 65–84 years), receiving Medicare, and hospitalized with acute myocardial infarction (AMI) in 1994–1995, and who were eligible for cardiac catheterization. Baseline chart reviews were taken from the Cooperative Cardiovascular Project and linked to Medicare health administrative data to provide a rich set of prognostic variables. Patients were followed up for 7 years through December 31, 2001, to assess the association between long-term survival and cardiac catheterization within 30 days of hospital admission. Main Outcome Measure Risk-adjusted relative mortality rate using each of the analytic methods. Results Patients who received cardiac catheterization (n=73 238) were younger and had lower AMI severity than those who did not. After adjustment for prognostic factors by using standard statistical risk-adjustment methods, cardiac catheterization was associated with a 50% relative decrease in mortality (for multivariable model risk adjustment: adjusted relative risk [RR], 0.51; 95% confidence interval [CI], 0.50–0.52; for propensity score risk adjustment: adjusted RR, 0.54; 95% CI, 0.53–0.55; and for propensity-based matching: adjusted RR, 0.54; 95% CI, 0.52–0.56). Using regional catheterization rate as an instrument, instrumental variable analysis showed a 16% relative decrease in mortality (adjusted RR, 0.84; 95% CI, 0.79–0.90). The survival benefits of routine invasive care from randomized clinical trials are between 8% and 21 %. Conclusions Estimates of the observational association of cardiac catheterization with long-term AMI mortality are highly sensitive to analytic method. All standard risk-adjustment methods have the same limitations regarding removal of unmeasured treatment selection biases. Compared with standard modeling, instrumental variable analysis may produce less biased estimates of treatment effects, but is more suited to answering policy questions than specific clinical questions. PMID:17227979

Features of influence of spatially inhomogeneous geomagnetic field on a humans heart rhythm variability

NASA Astrophysics Data System (ADS)

Tuzhilkin, D. A.; Borodin, A. S.; Shitov, A. V.

2017-11-01

The results of a study of the functioning of the human cardiovascular system in the epicentral zone of the Chui earthquake on a tectonic fault characterized by a sharp gradient zone of a regional magnetic field are presented. It is shown that in the dynamics of the daily distribution of RR-intervals, events corresponding to the time of visit by volunteers of sites characterized by the presence of a spatially inhomogeneous geomagnetic field are singled out. In particular, there is a decrease in the average period of cardiac contractions.

Atopy risk factors at birth and in adulthood.

PubMed

Ferraz, Erica; Garcia, Clécia Aparecida; Bettiol, Heloísa; Caldeira, Roseane Durães; Cardoso, Viviane Cunha; Arruda, Luiza Karla; Barbieri, Marco Antônio; Vianna, Elcio Oliveira

2011-01-01

To study the association between atopy and variables such as weight, length, and socioeconomic level at birth and in young adulthood. A total of 2,063 subjects were investigated in a prospective birth cohort study of individuals born in Ribeirão Preto, Brazil, in 1978/1979, and examined at the age of 23-25 years. Skin prick tests (SPT) for eight common allergens in Brazil were performed. Subjects with a wheal reaction ≥ 3 mm to one or more of the eight allergens tested were considered to be atopic. We used the log-binomial model (generalized linear model) in order to assess the association between atopy and birth or adult variables. The prevalence of positive SPT was 47.6%. Male gender was associated with an increased risk of atopy (relative risk [RR] = 1.18; 95% confidence interval [95%CI] 1.07-1.30). Low level of schooling was a protective factor against atopy, with a RR = 0.74; 95%CI 0.62-0.89. Living with a smoker in childhood was also associated with lower risk of atopy (RR = 0.87; 95%CI 0.79-0.96). Birth weight, length and order, maternal age, and intrauterine growth restriction were not associated with positive SPT. This study showed that male gender was associated with an increased risk of atopy. Low socioeconomic status, assessed by low level of schooling, was a protective factor against atopy. These data agree with the hygiene hypothesis.

Kinetics of cycle length dependence of ventricular repolarization: effect of autonomic blockade

NASA Technical Reports Server (NTRS)

Raeder, E. A.; Albrecht, P.; Perrott, M.; Cohen, R. J.

1995-01-01

INTRODUCTION: Beat-to-beat adaptation of ventricular repolarization duration to cardiac cycle length and autonomic activity has not been previously characterized in the spontaneously beating human heart. METHODS AND RESULTS: The ECG of 14 healthy subjects was recorded from the supine and upright positions. Autonomic blockade was accomplished by atropine and propranolol. RR and RT intervals were measured by a computer algorithm, and the impulse response (h) from RR to RT computed. In the supine position the maximal adjustment of the RT interval occurred in the first beat following a change in cycle length (hpeak = 17.8 +/- 1.6 msec/sec), but continued to be detectable for 3.8 seconds (2.9-4.7 sec). Propranolol attenuated the peak impulse response to 15.8 +/- 4.0 msec/sec (P = NS). In the standing position the peak impulse response was increased to 25.2 +/- 5.0 msec/sec (P = 0.004 vs supine), and the impulse response duration (hdur) shortened to 1.4 seconds (1.3-1.6). This was reversed by beta blockade (hpeak = 10.7 +/- 3.6 [P = 0.005 vs standing]; hdur = 5.5 sec [4.8-6.1]). Parasympathetic and combined autonomic blockade resulted in too little residual heart rate variability to estimate the impulse response accurately. The slope of the regression of delta RT and delta RR in the supine position was 0.0177 +/- 0.0016, which was closely correlated with the peak impulse response (r = 0.91). CONCLUSIONS: System identification techniques can assist in characterizing the cycle dependence of ventricular repolarization and may provide new insights into conditions associated with abnormal repolarization.

Abundance of Chemical Elements in RR Lyrae Variables and their Kinematic Parameters

NASA Astrophysics Data System (ADS)

Gozha, M. L.; Marsakov, V. A.; Koval', V. V.

2018-03-01

A catalog of the chemical and spatial-kinematic parameters of 415 RR Lyrae variables (Lyrids) in the galactic field is compiled. Spectroscopic determinations of the relative abundances of 13 chemical elements in 101 of the RR Lyrae variables are collected from 25 papers published between 1995 and 2017. The data from different sources are reduced to a single solar abundance scale. The mean weighted chemical abundances are calculated with coefficients inversely proportional to the reported errors. An analysis of the deviations in the published relative abundances in each star from the mean square values calculated from them reveals an absence of systematic biases among the results from the various articles. The rectangular coordinates of 407 of the RR Lyrae variables and the components of the three-dimensional (3D) velocities of 401 of the stars are calculated using data from several sources. The collected data on the abundances of chemical elements produced by various nuclear fusion processes for the RR Lyrae variables of the field, as well as the calculated 3D velocities, can be used for studying the evolution of the Galaxy.

Intravenous cannulation of adolescents does not affect the modulation of autonomic tone assessed by heart rate and blood pressure variability.

PubMed

Stewart, J M

2000-02-01

Invasive arterial monitoring alters autonomic tone. The effects of intravenous (i.v.) insertion are less clear. The author assessed the effects of i.v. insertion on autonomic activity in patients aged 11 to 19 years prior to head-up tilt by measuring heart rate, blood pressure, heart rate variability, blood pressure variability, and baroreceptor gain before and after i.v. insertion with continuous electrocardiography and arterial tonometry in patients with orthostatic tachycardia syndrome (OTS, N = 21), in patients who experienced simple fainting (N = 14), and in normal control subjects (N = 6). Five-minute samples were collected after 30 minutes supine. Fifteen minutes after i.v. insertion, data were collected again. These 5-minute samples were also collected in a separate control population without i.v. insertion after 30 minutes supine and again 30 minutes later. This population included 12 patients with OTS, 13 patients who experienced simple fainting, and 6 normal control subjects. Heart rate variability included the mean RR, the standard deviation of the RR interval (SDNN), and the root mean square of successive RR differences (RMSSD). Autoregressive spectral modeling was used. Low-frequency power (LFP, 0.04-0.15 Hz), high-frequency power (HFP, 0.15-0.40 Hz), and total power (TP, 0.01-0.40 Hz) were compared. Blood pressure variability included standard deviation of systolic blood pressure, LFP, and HFP. Baroreceptor gain at low frequency and high frequency was calculated from cross-spectral transfer function magnitudes when coherence was greater than 0.5. In patients with OTS, RR (790 +/- 50 msec), SDNN (54 +/- 6 msec), RMSSD (55 +/- 5 msec), LFP (422 +/- 200 ms2/Hz), HFP (846 +/- 400 ms2/Hz), and TP (1550 +/- 320 ms2/Hz) were less than in patients who experienced simple fainting (RR, 940 +/- 50 msec; SDNN, 84 +/- 10 msec; RMSSD, 91 +/- 7 msec; LFP, 880 +/- 342 ms2/Hz; HFP, 1720 +/- 210 ms2/Hz; and TP, 3228 +/- 490 ms2/Hz) or normal control subjects (RR, 920 +/- 30 msec; SDNN, 110 +/- 29 msec; RMSSD, 120 +/- 16 msec; LFP, 1600 +/- 331 ms2/Hz; HFP, 2700 +/- 526 ms2/Hz; and TP, 5400 +/- 1017 ms2/Hz). Blood pressure and blood pressure variability were not different in any group. Standard deviation, LFP, and HFP were, respectively, 5.24 +/- 0.8 mm Hg, 1.2 +/- 0.2, and 1.5 +/- 0.3 for patients with OTS; 4.6 +/- 0.4 mm Hg, 1.2 +/- 0.2, and 1.4 +/- 0.3 for patients who experienced simple fainting; and 5.55 +/- 1.0 mm Hg, 1.4 +/- 0.2, and 1.6 +/- 0.3 for normal control subjects. Baroreceptor gain at low frequency and high frequency in patients with OTS (16 +/- 4 msec/mm Hg, 17 +/- 5) was comparable to that in patients who experienced simple fainting (33 +/- 4, 32 +/- 3) and that in normal control subjects (31 +/- 8, 37 +/- 9). Heart rate variability differed between patients with OTS and patients who experienced simple fainting or normal control subjects, and blood pressure and blood pressure variability were not different, but no parameter changed after i.v. insertion. There were no differences from the groups that did not receive i.v. insertions. Data suggest, at most, a limited effect of i.v. insertion on autonomic function in adolescents.

Validation of Cardiovascular Parameters during NASA's Functional Task Test

NASA Technical Reports Server (NTRS)

Arzeno, N. M.; Stenger, M. B.; Bloomberg, J. J.; Platts, S. H.

2009-01-01

Microgravity exposure causes physiological deconditioning and impairs crewmember task performance. The Functional Task Test (FTT) is designed to correlate these physiological changes to performance in a series of operationally-relevant tasks. One of these, the Recovery from Fall/Stand Test (RFST), tests both the ability to recover from a prone position and cardiovascular responses to orthostasis. PURPOSE: Three minutes were chosen for the duration of this test, yet it is unknown if this is long enough to induce cardiovascular responses similar to the operational 5 min stand test. The purpose of this study was to determine the validity and reliability of heart rate variability (HRV) analysis of a 3 min stand and to examine the effect of spaceflight on these measures. METHODS: To determine the validity of using 3 vs. 5 min of standing to assess HRV, ECG was collected from 7 healthy subjects who participated in a 6 min RFST. Mean R-R interval (RR) and spectral HRV were measured in minutes 0-3 and 0-5 following the heart rate transient due to standing. Significant differences between the segments were determined by a paired t-test. To determine the reliability of the 3-min stand test, 13 healthy subjects completed 3 trials of the FTT on separate days, including the RFST with a 3 min stand. Analysis of variance (ANOVA) was performed on the HRV measures. One crewmember completed the FTT before a 14-day mission, on landing day (R+0) and one (R+1) day after returning to Earth. RESULTS VALIDITY: HRV measures reflecting autonomic activity were not significantly different during the 0-3 and 0-5 min segments. RELIABILITY: The average coefficient of variation for RR, systolic (SBP) and diastolic blood pressures during the RFST were less than 8% for the 3 sessions. ANOVA results yielded a greater inter-subject variability (p<0.006) than inter-session variability (p>0.05) for HRV in the RFST. SPACEFLIGHT: Lower RR and higher SBP were observed on R+0 in rest and stand. On R+1, both RR and SBP trended towards preflight rest and stand values. Postflight HRV showed higher LF/HF for rest and stand and lower HFnu during rest. CONCLUSION: These studies show that a 3 min stand delivers repeatable HRV data in the context of this larger series of FTT tests. Spaceflight-induced changes in blood pressure, RR and autonomic function (HRV) are evident from the RFST.

Prognostic Factors and Complications in Patients With Operational Peptic Ulcer Perforation in Northern Thailand.

PubMed

Suriya, Chutikarn; Kasatpibal, Nongyao; Kunaviktikul, Wipada; Kayee, Toranee

2014-02-01

Peptic ulcer perforation (PUP) is a very serious condition that leads to excessive complications and mortality. This study aimed to explore the possible prognostic factors and complications in patients with perforated peptic ulcer operation. A 6-year retrospective cohort study in Nakornping Hospital between January 1, 2005 and December 31, 2010 was conducted. The study included 912 patients who underwent PUP surgery. Patient characteristics were analyzed by using frequency, percentage, mean (standard deviation) and median (range). A comparison between groups was made. The Pearson's Chi-squared or Fisher's exact test was used for categorical variables, as appropriate. The Student's t test was used for continuous variables with normal distribution, and Wilcoxon rank sum test was performed for continuous variables with non-normal distributions. Exponential risk regression analysis was performed to estimate the relative risk (RR) for the prognostic factors with a probability value of < 0.05 as a statistically significant value. Post-operative length of stay was computed graphically based on Kaplan-Meier estimates. During the study period, 912 post-operative PUP patients were observed. The median age of patients was 78.5 (15 - 92) years, and 77.74% of the patients were male gender. Multivariate analysis showed that five prognostic indicators: underlying illnesses; liver disease (RR: 5.41; 95% confidence interval (CI): 1.36 - 21.56) and kidney disease (RR: 4.72; 95% CI: 1.05 - 21.11); duration of operation > 3 h (RR: 9.83; 95% CI: 1.61-59.66); unplanned admission to ICU (RR: 9.22; 95% CI: 1.55 - 54.68); and prolonged ventilation > 24 h (RR: 9.02; 95% CI: 0.42 - 9.98) were associated with post-operative PUP complications. Post-operative complications developed in 87 (9.54%) patients with 135 complications: 11 (1.21%) patients underwent re-operation, 32 (3.51%) patients suffered with surgical site infection, 74 (8.11%) patients encountered with pneumonia and 18 (1.97%) patients died. Post-operative complications including surgical site infection (incidence rate ratio (IRR): 2.00; 95% CI: 0.76 - 5.27), re-operation (IRR: 2.65; 95% CI: 0.73 - 9.62) and pneumonia (IRR: 6.97; 95% CI: 6.30 - 7.70) tend to be associated with mortality. The risk ratio showed a trend towards an increased risk for post-operative mortality with smaller values. However, this trend was not statistically significant. The findings might have clinical importance as to optimize the surgical management of PUP and to minimize the complications or mortality.

Bulge RR Lyrae stars in the VVV tile b201

NASA Astrophysics Data System (ADS)

Gran, F.; Minniti, D.; Saito, R. K.; Navarrete, C.; Dékány, I.; McDonald, I.; Contreras Ramos, R.; Catelan, M.

2015-03-01

Context. The VISTA Variables in the Vía Láctea (VVV) Survey is one of the six ESO public surveys currently ongoing at the VISTA telescope on Cerro Paranal, Chile. VVV uses near-IR (ZYJHKs) filters that at present provide photometry to a depth of Ks ~ 17.0 mag in up to 36 epochs spanning over four years, and aim at discovering more than 106 variable sources as well as trace the structure of the Galactic bulge and part of the southern disk. Aims: A variability search was performed to find RR Lyrae variable stars. The low stellar density of the VVV tile b201, which is centered at (ℓ,b) ~ (-9°, -9°), makes it suitable to search for variable stars. Previous studies have identified some RR Lyrae stars using optical bands that served to test our search procedure. The main goal is to measure the reddening, interstellar extinction, and distances of the RR Lyrae stars and to study their distribution on the Milky Way bulge. Methods: For each star in the tile with more than 25 epochs (~90% of the objects down to Ks ~ 17.0 mag), the standard deviation and χ2 test were calculated to identify variable candidates. Periods were determined using the analysis of variance. Objects with periods in the RR Lyrae range of 0.2 ≤ P ≤ 1.2 days were selected as candidate RR Lyrae. They were individually examined to exclude false positives. Results: A total of 1.5 sq deg were analyzed, and we found 39 RR Lyr stars, 27 of which belong to the ab-type and 12 to the c-type. Our analysis recovers all the previously identified RR Lyrae variables in the field and discovers 29 new RR Lyr stars. The reddening and extinction toward all the RRab stars in this tile were derived, and distance estimations were obtained through the period-luminosity relation. Despite the limited amount of RR Lyrae stars studied, our results are consistent with a spheroidal or central distribution around ~8.1 and ~8.5 kpc. for either the Cardelli or Nishiyama extinction law. Our analysis does not reveal a stream-like structure. Nevertheless, a larger area must be analyzed to definitively rule out streams. Based on observations taken within the ESO VISTA Public Survey VVV, Programme ID 179.B-2002.

The Optical Gravitational Lensing Experiment. Catalog of RR Lyr Stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Soszynski, I.; Udalski, A.; Szymanski, M.; Kubiak, M.; Pietrzynski, G.; Wozniak, P.; Zebrun, K.; Szewczyk, O.; Wyrzykowski, L.

2003-06-01

We present the catalog of RR Lyr stars discovered in a 4.5 square degrees area in the central parts of the Large Magellanic Cloud (LMC). Presented sample contains 7612 objects, including 5455 fundamental mode pulsators (RRab), 1655 first-overtone (RRc), 272 second-overtone (RRe) and 230 double-mode RR Lyr stars (RRd). Additionally we attach alist of several dozen other short-period pulsating variables. The catalog data include astrometry, periods, BVI photometry, amplitudes, and parameters of the Fourier decomposition of the I-band light curve of each object. We present density map of RR Lyr stars in the observed fields which shows that the variables are strongly concentrated toward the LMC center. The modal values of the period distribution for RRab, RRc and RRe stars are 0.573, 0.339 and 0.276 days, respectively. The period-luminosity diagrams for BVI magnitudes and for extinction insensitive index W_I are constructed. We provide the log P-I, log P-V and log P-W_I relations for RRab, RRc and RRe stars. The mean observed V-band magnitudes of RR Lyr stars in the LMC are 19.36 mag and 19.31 mag for ab and c types, respectively, while the extinction free values are 18.91 mag and 18.89 mag. We found a large number of RR Lyr stars pulsating in two modes closely spaced in the power spectrum. These stars are believed to exhibit non-radial pulsating modes. We discovered three stars which simultaneously reveal RR Lyr-type and eclipsing-type variability. If any of these objects were an eclipsing binary system containing RR Lyr star, then for the first time the direct determination of the mass of RR Lyr variable would be possible. We provide a list of six LMC star clusters which contain RR Lyr stars. The richest cluster, NGC 1835, hosts 84 RR Lyr variables. The period distribution of these stars suggests that NGC1835 shares features of Oosterhoff type I and type II groups. All presented data, including individual BVI observations and finding charts are available from the OGLE Internet archive.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunder, Andrea; Chaboyer, Brian; Layden, Andrew

New R-band observations of 21 local field RR Lyrae variable stars are used to explore the reliability of minimum light (V - R) colors as a tool for measuring interstellar reddening. For each star, R-band intensity mean magnitudes and light amplitudes are presented. Corresponding V-band light curves from the literature are supplemented with the new photometry, and (V - R) colors at minimum light are determined for a subset of these stars as well as for other stars in the literature. Two different definitions of minimum light color are examined, one which uses a Fourier decomposition to the V andmore » R light curves to find (V - R) at minimum V-band light, (V - R) {sup F} {sub min}, and the other which uses the average color between the phase interval 0.5-0.8, (V - R){sup {phi}}{sup (0.5-0.8)} {sub min}. From 31 stars with a wide range of metallicities and pulsation periods, the mean dereddened RR Lyrae color at minimum light is (V - R) {sup F} {sub min,0} = 0.28 {+-} 0.02 mag and (V - R){sup {phi}}{sup (0.5-0.8)} {sub min,0} = 0.27 {+-} 0.02 mag. As was found by Guldenschuh et al. using (V - I) colors, any dependence of the star's minimum light color on metallicity or pulsation amplitude is too weak to be formally detected. We find that the intrinsic (V - R) of Galactic bulge RR Lyrae stars are similar to those found by their local counterparts and hence that bulge RR0 Lyrae stars do not have anomalous colors as compared to the local RR Lyrae stars.« less

Comparison of rhythmic masticatory muscle activity during non-rapid eye movement sleep in guinea pigs and humans.

PubMed

Kato, Takafumi; Toyota, Risa; Haraki, Shingo; Yano, Hiroyuki; Higashiyama, Makoto; Ueno, Yoshio; Yano, Hiroshi; Sato, Fumihiko; Yatani, Hirofumi; Yoshida, Atsushi

2017-09-27

Rhythmic masticatory muscle activity can be a normal variant of oromotor activity, which can be exaggerated in patients with sleep bruxism. However, few studies have tested the possibility in naturally sleeping animals to study the neurophysiological mechanisms of rhythmic masticatory muscle activity. This study aimed to investigate the similarity of cortical, cardiac and electromyographic manifestations of rhythmic masticatory muscle activity occurring during non-rapid eye movement sleep between guinea pigs and human subjects. Polysomnographic recordings were made in 30 freely moving guinea pigs and in eight healthy human subjects. Burst cycle length, duration and activity of rhythmic masticatory muscle activity were compared with those for chewing. The time between R-waves in the electrocardiogram (RR interval) and electroencephalogram power spectrum were calculated to assess time-course changes in cardiac and cortical activities in relation to rhythmic masticatory muscle activity. In animals, in comparison with chewing, rhythmic masticatory muscle activity had a lower burst activity, longer burst duration and longer cycle length (P < 0.05), and greater variabilities were observed (P < 0.05). Rhythmic masticatory muscle activity occurring during non-rapid eye movement sleep [median (interquartile range): 5.2 (2.6-8.9) times per h] was preceded by a transient decrease in RR intervals, and was accompanied by a transient decrease in delta elelctroencephalogram power. In humans, masseter bursts of rhythmic masticatory muscle activity were characterized by a lower activity, longer duration and longer cycle length than those of chewing (P < 0.05). Rhythmic masticatory muscle activity during non-rapid eye movement sleep [1.4 (1.18-2.11) times per h] was preceded by a transient decrease in RR intervals and an increase in cortical activity. Rhythmic masticatory muscle activity in animals had common physiological components representing transient arousal-related rhythmic jaw motor activation in comparison to human subjects. © 2017 European Sleep Research Society.

VizieR Online Data Catalog: RR Lyraes in SDSS stripe 82 (Watkins+, 2009)

NASA Astrophysics Data System (ADS)

Watkins, L. L.; Evans, N. W.; Belokurov, V.; Smith, M. C.; Hewett, P. C.; Bramich, D. M.; Gilmore, G. F.; Irwin, M. J.; Vidrih, S.; Wyrzykowski, L.; Zucker, D. B.

2015-10-01

In this paper, we select first the variable objects in Stripe 82 and then the subset of RR Lyraes, using the Bramich et al. (2008MNRAS.386..887B, Cat. V/141) light-motion curve catalogue (LMCC) and HLC. We make a selection of the variable objects and an identification of RR Lyrae stars. (2 data files).

Cemented or cementless humeral fixation in reverse total shoulder arthroplasty? a systematic review.

PubMed

Phadnis, J; Huang, T; Watts, A; Krishnan, J; Bain, G I

2016-01-01

To date, there is insufficient evidence available to compare the outcome of cemented and uncemented fixation of the humeral stem in reverse shoulder arthroplasty (RSA). A systemic review comprising 41 clinical studies was performed to compare the functional outcome and rate of complications of cemented and uncemented stems in RSA. These included 1455 cemented and 329 uncemented shoulders. The clinical characteristics of the two groups were similar. Variables were compared using pooled frequency-weighted means and relative risk ratios (RR). Uncemented stems had a significantly higher incidence of early humeral stem migration (p < 0.001, RR 18.1, 95% confidence interval (CI) 5.0 to 65.2) and non-progressive radiolucent lines (p < 0.001, RR 2.4, 95% CI 1.7 to 3.4), but a significantly lower incidence of post-operative fractures of the acromion compared with cemented stems (p = 0.004, RR 14.3, 95% CI 0.9 to 232.8). There was no difference in the risk of stem loosening or revision between the groups. The cemented stems had a greater relative risk of infection (RR 3.3, 95% CI 0.8 to 13.7), nerve injury (RR 5.7, 95% CI 0.7 to 41.5) and thromboembolism (RR 3.9, 95% CI 0.2 to 66.6). The functional outcome and range of movement were equivalent in the two groups. RSA performed with an uncemented stem gives them equivalent functional outcome and a better complication profile than with a cemented stem. The natural history and clinical relevance of early stem migration and radiolucent lines found with uncemented stems requires further long-term study. This study demonstrates that uncemented stems have at least equivalent clinical and radiographic outcomes compared with cemented stems when used for reverse total shoulder arthroplasty. ©2016 The British Editorial Society of Bone & Joint Surgery.

Slowed atrial and atrioventricular conduction and depressed HRV in a murine model of hypertrophic cardiomyopathy.

PubMed

Lim, Wei-Wen; Baumert, Mathias; Neo, Melissa; Kuklik, Pawel; Ganesan, Anand N; Lau, Dennis H; Tsoutsman, Tatiana; Semsarian, Christopher; Sanders, Prashanthan; Saint, David A

2016-01-01

Hypertrophic cardiomyopathy (HCM) is a common heritable cardiac disorder with diverse clinical outcomes including sudden death, heart failure, and stroke. Depressed heart rate variability (HRV), a measure of cardiac autonomic regulation, has been shown to predict mortality in patients with cardiovascular disease. Cardiac autonomic remodelling in animal models of HCM are not well characterised. This study analysed Gly203Ser cardiac troponin-I transgenic (TG) male mice previously demonstrated to develop hallmarks of HCM by age 21 weeks. 33 mice aged 30 and 50 weeks underwent continuous electrocardiogram (ECG) recording for 30 min under anaesthesia. TG mice demonstrated prolonged P-wave duration (P < 0.001) and PR intervals (P < 0.001) compared to controls. Additionally, TG mice demonstrated depressed standard deviation of RR intervals (SDRR; P < 0.01), coefficient of variation of RR intervals (CVRR; P < 0.001) and standard deviation of heart rate (SDHR; P < 0.001) compared to controls. Additionally, total power was significantly reduced in TG mice (P < 0.05). No significant age-related difference in either strain was observed in ECG or HRV parameters. Mice with HCM developed slowed atrial and atrioventricular conduction and depressed HRV. These changes were conserved with increasing age. This finding may be indicative of atrial and ventricular hypertrophy or dysfunction, and perhaps an indication of worse clinical outcome in heart failure progression in HCM patients. © 2015 Wiley Publishing Asia Pty Ltd.

Sildenafil improves heart rate variability in dogs with asymptomatic myxomatous mitral valve degeneration

PubMed Central

PIRINTR, Prapawadee; SAENGKLUB, Nakkawee; LIMPRASUTR, Vudhiporn; SAWANGKOON, Suwanakiet; KIJTAWORNRAT, Anusak

2017-01-01

Myxomatous mitral valve degeneration (MMVD) causes an imbalance of sympathovagal activity resulted in poor cardiac outcomes. Phosphodiesterase-5 inhibitors have been revealed cardioprotective effect in patients with heart diseases. This study aimed to 1) compare the heart rate variability (HRV) between asymptomatic MMVD and healthy dogs and 2) assess long-term effects of sildenafil and enalapril on time- and frequency-domains analyzes. Thirty-four dogs with MMVD stage B1 or B2 and thirteen healthy dogs were recruited into the study. MMVD dogs were divided into 3 subgroups: control (n=13), sildenafil (n=12) and enalapril (n=9). HRV was analyzed from 1-hr Holter recording at baseline (D0) in all dogs and at 30, 90 and 180 days after treatment. The results showed that MMVD dogs had significant higher heart rate (HR), systemic blood pressures, the ratio of low to high frequency (LF/HF) and had significant decreased standard deviation of all normal to normal RR intervals (SDNN) and the percentage of the number of normal-to-normal sinus RR intervals with differences >50 msec computed over the entire recording (pNN50) when compared with healthy dogs (P<0.05). Neither time nor frequency domain parameters were different among subgroups of MMVD dogs at D0. After treatment with sildenafil for 90 days, both time- and frequency-domain parameters were significantly increased when compared with control and enalapril groups. This study demonstrated that sildenafil improves HRV in asymptomatic MMVD dogs suggesting that sildenafil should be used in the MMVD dogs to restore the sympathovagal balance. PMID:28717064

Nocturnal heart rate variability is lower in temporomandibular disorder patients than in healthy, pain-free individuals.

PubMed

Eze-Nliam, Chete M; Quartana, Phillip J; Quain, Angela M; Smith, Michael T

2011-01-01

To determine whether patients with a painful myofascial temporomandibular disorder (TMD) have diminished nocturnal heart rate variability (HRV), a marker of autonomic nervous system (ANS) dysfunction, relative to healthy, pain-free controls. Participants with myofascial TMD and healthy, pain-free volunteers underwent nocturnal polysomnography studies during which HRV indices were measured. Multiple linear regression analyses were used to determine whether TMD status exerted unique effects on HRV. Ninety-five participants (n = 37 TMD; n = 58 controls) were included in the analyses. The TMD group had a lower standard deviation of R-R intervals (89.81 ± 23.54 ms versus 107.93 ± 34.42 ms, P ⋜ .01), a lower root mean squared successive difference (RMSSD) of R-R intervals (54.78 ± 27.37 ms versus 81.88 ± 46.43 ms, P < .01), and a lower high frequency spectral power (2336.89 ± 1224.64 ms² versus 2861.78 ± 1319 ms², P = .05) than the control group. The ratio of the low-frequency (LF) to the high-frequency (HF) spectral power was higher in the TMD group (2.47 ± 2 versus 1.38 ± 0.65, P < .01). The differences in RMSSD (91.21 ms versus 112.03 ms, P = .05) and LF:HF ratio (0.71 versus 0.32, P < .01) remained significant after controlling for age and psychological distress. Myofascial TMD patients revealed lower nocturnal HRV than healthy, pain-free controls. Further research should focus on processes that address this ANS imbalance, which may potentially lead to effective therapeutic interventions.

Effect of weight loss on sympatho-vagal balance in subjects with grade-3 obesity: restrictive surgery versus hypocaloric diet.

PubMed

Pontiroli, Antonio E; Merlotti, Claudia; Veronelli, Annamaria; Lombardi, Federico

2013-12-01

Few and mostly uncontrolled studies indicate that weight loss improves heart rate variability (HRV) in grade-3 obesity. The aim of this study was to compare in grade-3 obesity surgery and hypocaloric diet on clinical and metabolic variables and on autonomic indices of HRV. Twenty-four subjects (body mass index, BMI 45.5 ± 9.13 kg/m(2)) underwent surgery (n = 12, gastric banding, LAGB) or received hypocaloric diet (n = 12, 1,000-1,200 kg/day). Clinical [BMI, systolic blood pressure (SBP) and diastolic blood pressure (DBP), heart rate] and metabolic variables [glucose, cholesterol, HDL- and LDL-cholesterol, triglycerides, AST and ALT transaminases] and 24-h Holter electrocardiographic-derived HRV parameters [R-R interval, standard deviation of R-R intervals (SDNN); low/high-frequency (LF/HF) ratio, and QT interval] were measured at baseline and after 6 months. The two groups were identical at baseline. BMI (-7.5 ± 3.57 kg/m(2), mean ± SD), glucose (-24.1 ± 26.77 mg/dL), SBP (-16.7 ± 22.19 mmHg) and DBP (-6.2 ± 8.56 mmHg) decreased in LAGB subjects (p < 0.05) and remained unchanged in controls. At 6 months, SDNN increased in LAGB subjects (+25.0 ± 37.19 ms, p < 0.05) and LF/HF ratio diminished (2.9 ± 1.84 vs. 4.9 ± 2.78; p = 0.01), with no change in controls; LF (daytime) and HF (24 h and daytime) increased in LAGB subjects, with no change in controls. Decrease in BMI correlated with SBP and DBP decrease (p < 0.05), and DBP decrease correlated with HR decrease (p < 0.05) and QT shortening (p < 0.05). Weight loss is associated with improvement of glucose metabolism, of blood pressure, and with changes in time and frequency domain parameters of HRV; all these changes indicate recovery of a more physiological autonomic control, with increase in parasympathetic and reduction in sympathetic indices of HRV.

Sample size, power calculations, and their implications for the cost of thorough studies of drug induced QT interval prolongation.

PubMed

Malik, Marek; Hnatkova, Katerina; Batchvarov, Velislav; Gang, Yi; Smetana, Peter; Camm, A John

2004-12-01

Regulatory authorities require new drugs to be investigated using a so-called "thorough QT/QTc study" to identify compounds with a potential of influencing cardiac repolarization in man. Presently drafted regulatory consensus requires these studies to be powered for the statistical detection of QTc interval changes as small as 5 ms. Since this translates into a noticeable drug development burden, strategies need to be identified allowing the size and thus the cost of thorough QT/QTc studies to be minimized. This study investigated the influence of QT and RR interval data quality and the precision of heart rate correction on the sample sizes of thorough QT/QTc studies. In 57 healthy subjects (26 women, age range 19-42 years), a total of 4,195 drug-free digital electrocardiograms (ECG) were obtained (65-84 ECGs per subject). All ECG parameters were measured manually using the most accurate approach with reconciliation of measurement differences between different cardiologists and aligning the measurements of corresponding ECG patterns. From the data derived in this measurement process, seven different levels of QT/RR data quality were obtained, ranging from the simplest approach of measuring 3 beats in one ECG lead to the most exact approach. Each of these QT/RR data-sets was processed with eight different heart rate corrections ranging from Bazett and Fridericia corrections to the individual QT/RR regression modelling with optimization of QT/RR curvature. For each combination of data quality and heart rate correction, standard deviation of individual mean QTc values and mean of individual standard deviations of QTc values were calculated and used to derive the size of thorough QT/QTc studies with an 80% power to detect 5 ms QTc changes at the significance level of 0.05. Irrespective of data quality and heart rate corrections, the necessary sample sizes of studies based on between-subject comparisons (e.g., parallel studies) are very substantial requiring >140 subjects per group. However, the required study size may be substantially reduced in investigations based on within-subject comparisons (e.g., crossover studies or studies of several parallel groups each crossing over an active treatment with placebo). While simple measurement approaches with ad-hoc heart rate correction still lead to requirements of >150 subjects, the combination of best data quality with most accurate individualized heart rate correction decreases the variability of QTc measurements in each individual very substantially. In the data of this study, the average of standard deviations of QTc values calculated separately in each individual was only 5.2 ms. Such a variability in QTc data translates to only 18 subjects per study group (e.g., the size of a complete one-group crossover study) to detect 5 ms QTc change with an 80% power. Cost calculations show that by involving the most stringent ECG handling and measurement, the cost of a thorough QT/QTc study may be reduced to approximately 25%-30% of the cost imposed by the simple ECG reading (e.g., three complexes in one lead only).

Variable Stars in the Draco Dwarf Spheroidal Galaxy

NASA Astrophysics Data System (ADS)

Harris, H. C.; Silberman, N. A.; Smith, H. A.

A new survey of the variable stars in the Draco dwarf spheroidal galaxy updates the pioneering study of this galaxy by Baade and Swope (1961). Our improved data, taken in BVI filters with CCD cameras on three telescopes at more than 80 epochs, allow us to investigate the known variables and to discover new, mostly low-amplitude variables. Approximately 300 variables are found and classified, more than double the number of variables analyzed previously. Most are RR Lyraes, with a small fraction of Anomalous Cepheids. This large sample of variables provides a unique opportunity to study the properties of these stars in a single system. This paper discusses the census of RR Lyraes, including RRc-type, double-mode, and Blazhko-effect RR Lyraes, as well as Anomalous Cepheids, and Type II Cepheids in Draco.

Effects of sildenafil citrate (viagra) on cardiac repolarization and on autonomic control in subjects with chronic heart failure.

PubMed

Piccirillo, Gianfranco; Nocco, Marialuce; Lionetti, Marco; Moisè, Antonio; Naso, Camilla; Marigliano, Vincenzo; Cacciafesta, Mauro

2002-04-01

Cases of sudden death associated with sildenafil citrate use have been reported in men with coronary artery disease. The aim of this study was to investigate the drug's effect on cardiac repolarization and sinus autonomic and vascular control in men with mild chronic heart failure (CHF; New York Heart Association classification II). Changes in these variables could predispose patients to malignant ventricular arrhythmias. We measured QT dispersion, the QT-RR slope, and the index of QT variability (QTVI) and analyzed spectral power of RR and systolic blood pressure variability in 10 men with dilated cardiomyopathy and in 10 control subjects after administration of a single 50-mg oral dose of sildenafil citrate or placebo at rest (not followed with any attempt at intercourse). In both groups, oral sildenafil citrate decreased the systolic blood pressure (P <.05) and increased the heart rate (P <.05). In subjects with CHF, it also increased the QT-RR (P <.001) and QTVI (from -0.45 +/- 0.07 to -0.27 +/- 0.07; P <.001), but in controls, it increased the QTVI (from -1.20 +/- 0.08 to -0.78 +/-.014; P <.001). In these subjects and controls, oral sildenafil citrate induced a significant reduction in high frequency, expressed in absolute power (subjects with CHF: from 4.04 +/- 0.14 to 3.43 +/- 0.16 natural logarithm ms2; P <.001; controls: from 5.61 +/- 0.44 to 4.98 +/- 0.32 natural logarithm ms2; P <.05) and in normalized units (P <.05). In subjects with CHF but not in controls, it also significantly increased the low frequency to high frequency ratio (from 1.3 +/- 0.12 to 1.89 +/- 0.16; P <.001) and low frequency expressed in normalized units (P <.05). Sildenafil citrate caused no significant changes in the QT interval or dispersion. These findings indicate that, in men with heart failure, sildenafil citrate reduces vagal modulation and increases sympathetic modulation, probably through its reflex vasodilatory action. The autonomic system changes induced with sildenafil citrate could alter QT dynamics. Both changes could favor the onset of lethal ventricular arrhythmias. At the dose usually taken for erectile dysfunction, sildenafil citrate has no direct effect on cardiac repolarization (QT interval or dispersion).

The Half RR Rule: A Poor Rule of Thumb and Not a Risk Assessment Tool for QT Interval Prolongation.

PubMed

Berling, Ingrid; Isbister, Geoffrey K

2015-10-01

Measuring the QT interval on an electrocardiogram (ECG) is integral to risk assessment of Torsade de Pointes (TdP). This study aimed to investigate the accuracy of the 1/2 RR rule as a risk assessment tool for drug-induced TdP, comparing it to the QT nomogram, Bazett's corrected QT (QTcB), and Fridericia's corrected QT (QTcF). The authors calculated sensitivity and specificity of the 1/2 RR rule using a published data set of 129 cases of drug-induced TdP and 316 controls (noncardiotoxic overdoses), compared to the QT nomogram, QTcB > 500 msec and QTcF > 500 msec. To further determine the value of the 1/2 RR rule, its observed positive, and negative agreement were calculated when compared to the QT nomogram for determining an abnormal QT in eight samples of different drugs in overdose. The sensitivity and specificity of the 1/2 RR rule were 88% (95% confidence interval [CI] = 80% to 93%) and 53% (95% CI = 47% to 58%), respectively, compared to the QT nomogram (sensitivity = 97%, 95% CI = 92% to 99%; specificity = 99%, 95% CI = 97% to 100%). It was also less sensitive than QTcB > 500 msec and had a lower specificity than QTcB > 500 msec and QTcF > 500 msec. In drug overdose patients, the 1/2 RR rule had poor observed agreement averaging 41%, which was mainly due to poor positive agreement, except for amisulpride where there was good agreement. The 1/2 RR rule was not as sensitive as the QT nomogram or QTcB > 500 msec for drug-induced TdP. It had poor positive agreement in almost all overdose patients, resulting in over half of patients receiving unnecessary cardiac monitoring and repeat ECGs. © 2015 by the Society for Academic Emergency Medicine.

VizieR Online Data Catalog: RR Lyrae in SDSS Stripe 82 (Suveges+, 2012)

NASA Astrophysics Data System (ADS)

Suveges, M.; Sesar, B.; Varadi, M.; Mowlavi, N.; Becker, A. C.; Ivezic, Z.; Beck, M.; Nienartowicz, K.; Rimoldini, L.; Dubath, P.; Bartholdi, P.; Eyer, L.

2013-05-01

We propose a robust principal component analysis framework for the exploitation of multiband photometric measurements in large surveys. Period search results are improved using the time-series of the first principal component due to its optimized signal-to-noise ratio. The presence of correlated excess variations in the multivariate time-series enables the detection of weaker variability. Furthermore, the direction of the largest variance differs for certain types of variable stars. This can be used as an efficient attribute for classification. The application of the method to a subsample of Sloan Digital Sky Survey Stripe 82 data yielded 132 high-amplitude delta Scuti variables. We also found 129 new RR Lyrae variables, complementary to the catalogue of Sesar et al., extending the halo area mapped by Stripe 82 RR Lyrae stars towards the Galactic bulge. The sample also comprises 25 multiperiodic or Blazhko RR Lyrae stars. (8 data files).

Quantitative analysis of ventricular ectopic beats in short-term RR interval recordings to predict imminent ventricular tachyarrhythmia.

PubMed

Martínez-Alanis, Marisol; Ruiz-Velasco, Silvia; Lerma, Claudia

2016-12-15

Most approaches to predict ventricular tachyarrhythmias which are based on RR intervals consider only sinus beats, excluding premature ventricular complexes (PVCs). The method known as heartprint, which analyses PVCs and their characteristics, has prognostic value for fatal arrhythmias on long recordings of RR intervals (>70,000 beats). To evaluate characteristics of PVCs from short term recordings (around 1000 beats) and their prognostic value for imminent sustained tachyarrhythmia. We analyzed 132 pairs of short term RR interval recordings (one before tachyarrhythmia and one control) obtained from 78 patients. Patients were classified into two groups based on the history of accelerated heart rate (HR) (HR>90bpm) before a tachyarrhythmia episode. Heartprint indexes, such as mean coupling interval (meanCI) and the number of occurrences of the most prevalent form of PVCs (SNIB) were calculated. The predictive value of all the indexes and of the combination of different indexes was calculated. MeanCI shorter than 482ms and the occurrence of more repetitive arrhythmias (sNIB≥2.5), had a significant prognostic value for patients with accelerated heart rate: adjusted odds ratio of 2.63 (1.33-5.17) for meanCI and 2.28 (1.20-4.33) for sNIB. Combining these indexes increases the adjusted odds ratio: 10.94 (3.89-30.80). High prevalence of repeating forms of PVCs and shorter CI are potentially useful risk markers of imminent ventricular tachyarrhythmia. Knowing if a patient has history of VT/VF preceded by accelerated HR, improves the prognostic value of these risk markers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Heart rate variability as determinism with jump stochastic parameters.

PubMed

Zheng, Jiongxuan; Skufca, Joseph D; Bollt, Erik M

2013-08-01

We use measured heart rate information (RR intervals) to develop a one-dimensional nonlinear map that describes short term deterministic behavior in the data. Our study suggests that there is a stochastic parameter with persistence which causes the heart rate and rhythm system to wander about a bifurcation point. We propose a modified circle map with a jump process noise term as a model which can qualitatively capture such this behavior of low dimensional transient determinism with occasional (stochastically defined) jumps from one deterministic system to another within a one parameter family of deterministic systems.

Effects of seasonal smog on asthma and COPD exacerbations requiring emergency visits in Chiang Mai, Thailand.

PubMed

Pothirat, Chaicharn; Tosukhowong, Apiwat; Chaiwong, Warawut; Liwsrisakun, Chalerm; Inchai, Juthamas

2016-12-01

Seasonal smog produces particulate matters that are less than 10 microns in diameter (PM₁₀), which are known to have several impacts on the respiratory system. This study was to determine the association of an increased PM10 level due to seasonal smog in Chiang Mai and emergency visits for asthma and chronic obstructive pulmonary disease (COPD) exacerbations. A retrospective cross-sectional study was conducted between the months of January and March from 2006 until 2009. The association of an increased PM₁₀ level and the daily number of asthma and COPD exacerbations were analyzed using a generalized linear model; a Poisson regression model was fit to the number of daily emergency visits using predictor variables: lags of PM10, day of the week, and time. There were a total of 917 emergency visits for acute exacerbations of asthma and COPD, with a median of 2 visits per day (range 0-10). The median PM₁₀ level during the same interval was 64.5 microgram per cubic meter (μg/m3) (16-304). For every 10 μg/m3 rise in PM10 concentration, there was a lag time of 6 days for asthma exacerbations [Adjusted relative risk (RR)=1.020; 95% confident interval (CI), 1.001-1.040; (p=0.014)], 7 days for COPD exacerbations [RR=1.030; 95%CI, 1.010-1.050 (p=0.024)] and 7 days for all exacerbations [RR=1.030 95%CI, 1.010-1.040 (p<0.001)]. This study confirms the effect of increasing PM₁₀ concentrations from seasonal smog on asthma and COPD exacerbations. However, there was an approximately 1 week lag time between the elevated PM₁₀ levels and time to emergency visits due to disease exacerbation.

Lung cancer risk prediction to select smokers for screening CT--a model based on the Italian COSMOS trial.

PubMed

Maisonneuve, Patrick; Bagnardi, Vincenzo; Bellomi, Massimo; Spaggiari, Lorenzo; Pelosi, Giuseppe; Rampinelli, Cristiano; Bertolotti, Raffaella; Rotmensz, Nicole; Field, John K; Decensi, Andrea; Veronesi, Giulia

2011-11-01

Screening with low-dose helical computed tomography (CT) has been shown to significantly reduce lung cancer mortality but the optimal target population and time interval to subsequent screening are yet to be defined. We developed two models to stratify individual smokers according to risk of developing lung cancer. We first used the number of lung cancers detected at baseline screening CT in the 5,203 asymptomatic participants of the COSMOS trial to recalibrate the Bach model, which we propose using to select smokers for screening. Next, we incorporated lung nodule characteristics and presence of emphysema identified at baseline CT into the Bach model and proposed the resulting multivariable model to predict lung cancer risk in screened smokers after baseline CT. Age and smoking exposure were the main determinants of lung cancer risk. The recalibrated Bach model accurately predicted lung cancers detected during the first year of screening. Presence of nonsolid nodules (RR = 10.1, 95% CI = 5.57-18.5), nodule size more than 8 mm (RR = 9.89, 95% CI = 5.84-16.8), and emphysema (RR = 2.36, 95% CI = 1.59-3.49) at baseline CT were all significant predictors of subsequent lung cancers. Incorporation of these variables into the Bach model increased the predictive value of the multivariable model (c-index = 0.759, internal validation). The recalibrated Bach model seems suitable for selecting the higher risk population for recruitment for large-scale CT screening. The Bach model incorporating CT findings at baseline screening could help defining the time interval to subsequent screening in individual participants. Further studies are necessary to validate these models.

Dental erosion among 12-year-old schoolchildren: a population-based cross-sectional study in South Brazil.

PubMed

Alves, Luana Severo; Brusius, Carolina Doege; Damé-Teixeira, Nailê; Maltz, Marisa; Susin, Cristiano

2015-12-01

To assess the epidemiology and risk indicators for dental erosion among 12-year-old schoolchildren in South Brazil. A population-based cross-sectional survey was conducted in Porto Alegre, Brazil, using a representative sample of 12-year-old schoolchildren (n = 1,528). Dental erosion was recorded according to the Basic Erosive Wear Examination (BEWE) index. Parents answered questions on socio-economic status, brushing frequency and general health. Schoolchildren answered questions on dietary habits. Anthropometric data were collected. Statistical analysis included logistic and Poisson regression models. The prevalence of dental erosion was 15% [95% confidence interval (95% CI): 13.6-16.5], being mainly mild erosion. Boys [odds ratio (OR) = 1.57, 95% CI: 1.17-2.10], private school attendees (OR = 1.45, 95% CI: 1.01-2.06) and schoolchildren reporting the daily consumption of soft drinks (OR = 5.04, 95% CI: 1.17-21.71) were more likely to have at least one tooth with dental erosion. Gender [boys, rate ratio (RR) = 1.66, 95% CI: 1.28-2.17], type of school (private, RR = 1.89, 95% CI: 1.53-2.35), the consumption of soft drinks (sometimes: RR = 5.27, 95% CI: 1.46-19.05; daily: RR = 6.82, 95% CI: 1.39-33.50) and the daily consumption of lemon (RR = 1.49, 95% CI: 1.11-2.00) were significantly associated with the number of affected surfaces. The present study found a moderate prevalence of dental erosion among young schoolchildren, with mild erosion being the most prevalent condition. Socio demographic variables and dietary habits were associated with dental erosion in this population. © 2015 FDI World Dental Federation.

The Globular Cluster NGC 6402 (M14). II. Variable Stars

NASA Astrophysics Data System (ADS)

Contreras Peña, C.; Catelan, M.; Grundahl, F.; Stephens, A. W.; Smith, H. A.

2018-03-01

We present time-series BVI photometry for the Galactic globular cluster NGC 6402 (M14). The data consist of ∼137 images per filter, obtained using the 0.9 and 1.0 m SMARTS telescopes at the Cerro Tololo Inter-American Observatory. The images were obtained during two observing runs in 2006–2007. The image-subtraction package ISIS, along with DAOPHOT II/ALLFRAME, was used to perform crowded-field photometry and search for variable stars. We identified 130 variables, eight of which are new discoveries. The variable star population is comprised of 56 ab-type RR Lyrae stars, 54 c-type RR Lyrae, 6 type II Cepheids, 1 W UMa star, 1 detached eclipsing binary, and 12 long-period variables. We provide Fourier decomposition parameters for the RR Lyrae, and discuss the physical parameters and photometric metallicity derived therefrom. The M14 distance modulus is also discussed, based on different approaches for the calibration of the absolute magnitudes of RR Lyrae stars. The possible presence of second-overtone RR Lyrae in M14 is critically addressed, with our results arguing against this possibility. By considering all of the RR Lyrae stars as members of the cluster, we derive < {P}ab > =0.589 {{d}}{{a}}{{y}}{{s}}. This, together with the position of the RR Lyrae stars of both Bailey types in the period–amplitude diagram, suggests an Oosterhoff-intermediate classification for the cluster. Such an intermediate Oosterhoff type is much more commonly found in nearby extragalactic systems, and we critically discuss several other possible indications that may point to an extragalactic origin for this cluster. Based on observations obtained with the 0.9 m and 1 m telescopes at the Cerro Tololo Inter-American Observatory, Chile, operated by the SMARTS consortium.

Variable Stars In the Unusual, Metal-Rich Globular Cluster

NASA Technical Reports Server (NTRS)

Pritzl, Barton J.; Smith, Horace A.; Catelan, Marcio; Sweigart, Allen V.; Oegerle, William R. (Technical Monitor)

2002-01-01

We have undertaken a search for variable stars in the metal-rich globular cluster NGC 6388 using time-series BV photometry. Twenty-eight new variables were found in this survey, increasing the total number of variables found near NGC 6388 to approx. 57. A significant number of the variables are RR Lyrae (approx. 14), most of which are probable cluster members. The periods of the fundamental mode RR Lyrae are shown to be unusually long compared to metal-rich field stars. The existence of these long period RRab stars suggests that the horizontal branch of NGC 6388 is unusually bright. This implies that the metallicity-luminosity relationship for RR Lyrae stars is not universal if the RR Lyrae in NGC 6388 are indeed metal-rich. We consider the alternative possibility that the stars in NGC 6388 may span a range in [Fe/H]. Four candidate Population II Cepheids were also found. If they are members of the cluster, NGC 6388 would be the most metal-rich globular cluster to contain Population II Cepheids. The mean V magnitude of the RR Lyrae is found to be 16.85 +/- 0.05 resulting in a distance of 9.0 to 10.3 kpc, for a range of assumed values of (M(sub V)) for RR Lyrae. We determine the reddening of the cluster to be E(B - V) = 0.40 +/- 0.03 mag, with differential reddening across the face of the cluster. We discuss the difficulty in determining the Oosterhoff classification of NGC 6388 and NGC 6441 due to the unusual nature of their RR Lyrae, and address evolutionary constraints on a recent suggestion that they are of Oosterhoff type II.

Recurrence patterns and factors associated with regular, irregular, and late return to service of female pigs and their lifetime performance on southern European farms.

PubMed

Tani, S; Piñeiro, C; Koketsu, Y

2016-05-01

A return-to-service occurrence increases nonproductive days of female pigs and decreases herd productivity. The objectives of the present study were 1) to characterize 3 return types based on reservice intervals in female pigs on southern European farms, 2) to determine return risks and recurrence patterns for these types of returns, and 3) to assess lifetime performance of females with the 3 types of returns. We analyzed 653,528 service records and lifetime records of 114,906 females on 125 farms between 2008 and 2013. Reservice intervals were categorized into 3 groups: regular returns (RR: 18 to 24 d), irregular returns (IR: 25 to 38 d), and late returns (LR: 39 d or later). Multilevel generalized linear models were applied to the data. There were 64,385 reservice records (9.9%), with mean risks of RR, IR, and LR per service (±SEM) of 3.6% ± 0.06%, 2.5% ± 0.05%, and 3.0% ± 0.06%, respectively. Of the 43,931 first-returned females, 32.7% had a second return in the same or later parity. Also, 18.8%, 10.2%, and 11.6% of females that had RR, IR, and LR first returns, respectively, had a second return of the same return type. Summer servicing was associated with greater RR, IR, and LR risks in gilts. Also, increased gilt age at first mating was associated with RR ( = 0.03) and LR risk ( < 0.01) but not with IR risk ( = 0.53). For sows, factors associated with greater RR, IR, or LR risks were summer servicing, lower parity, farrowing more stillborn piglets, and having a weaning-to-first-mating interval of 7 d or more ( < 0.01). In lifetime, 33.5% of serviced females had 1 or more returns. These returned females had 41.5 more lifetime nonproductive days than nonreturn females but also 1.9 more lifetime pigs born alive ( < 0.01). We recommend that producers closely monitor females in high-risk groups to reduce their return-to-service intervals.

Multi-Epoch Mid-Infrared Interferometric Observations of the Oxygen-rich Mira Variable Star RR Aql with the VLTI/MIDI Instrument

DTIC Science & Technology

2011-01-01

VLTI/ MIDI Instrument I. Karovicova,1,3 M. Wittkowski,1 D. A. Boboltz,2 E. Fossat,3 K. Ohnaka,4 and M. Scholz5,6 1European Southern Observatory...the oxygen-rich Mira variable RR Aql at 13 epochs covering 4 pulsation cycles with the MIDI instrument at the VLTI. We modeled the observed data...Variable Star RR Aql with the VLTI/ MIDI Instrument 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e

Brazilian Jiu-Jitsu Simulated Competition Part I: Metabolic, Hormonal, Cellular Damage, and Heart Rate Responses.

PubMed

Andreato, Leonardo V; Julio, Ursula F; Panissa, Valeria L G; Esteves, João V D C; Hardt, Felipe; de Moraes, Solange M F; de Souza, Camila O; Franchini, Emerson

2015-09-01

The aim of this study was to analyze physiological responses in Brazilian jiu-jitsu athletes during simulated competition. To this end, 10 athletes (age: 28 ± 4 years, body mass: 81.8 ± 7.4 kg, body fat: 13.0 ± 4.8%, systematic practice: 11 ± 4 years) were analyzed in simulated competition (4 matches of 10 minutes). Blood samples were taken to assess energy demand, hormonal responses, and cell damage. Additionally, the heart rate variability (HRV) response was analyzed. The main results show that in simulated competition, during the last matches, athletes had lower lactate (p < 0.001), epinephrine (p < 0.001), norepinephrine (p < 0.001), and insulin (p = 0.002) concentrations. Increases observed in creatine kinase (p < 0.001), aspartate aminotransferase (p < 0.001), alanine aminotransferase (p = 0.007), and creatinine (p < 0.001) seen, especially, in the last matches are indicative of possible cell damage. The HRV reflected a decrease in the RR medium (average of the normal R-R intervals) (p = 0.001) during the competition. Thus, it is concluded that successive matches from competition generate a gradual decrease of adrenergic and glycolytic activities, which is accompanied by a gradual increase in cell damage markers and decrease in the RR medium of the HRV.

Determination of heart rate variability with an electronic stethoscope.

PubMed

Kamran, Haroon; Naggar, Isaac; Oniyuke, Francisca; Palomeque, Mercy; Chokshi, Priya; Salciccioli, Louis; Stewart, Mark; Lazar, Jason M

2013-02-01

Heart rate variability (HRV) is widely used to characterize cardiac autonomic function by measuring beat-to-beat alterations in heart rate. Decreased HRV has been found predictive of worse cardiovascular (CV) outcomes. HRV is determined from time intervals between QRS complexes recorded by electrocardiography (ECG) for several minutes to 24 h. Although cardiac auscultation with a stethoscope is performed routinely on patients, the human ear cannot detect heart sound time intervals. The electronic stethoscope digitally processes heart sounds, from which cardiac time intervals can be obtained. Accordingly, the objective of this study was to determine the feasibility of obtaining HRV from electronically recorded heart sounds. We prospectively studied 50 subjects with and without CV risk factors/disease and simultaneously recorded single lead ECG and heart sounds for 2 min. Time and frequency measures of HRV were calculated from R-R and S1-S1 intervals and were compared using intra-class correlation coefficients (ICC). The majority of the indices were strongly correlated (ICC 0.73-1.0), while the remaining indices were moderately correlated (ICC 0.56-0.63). In conclusion, we found HRV measures determined from S1-S1 are in agreement with those determined by single lead ECG, and we demonstrate and discuss differences in the measures in detail. In addition to characterizing cardiac murmurs and time intervals, the electronic stethoscope holds promise as a convenient low-cost tool to determine HRV in the hospital and outpatient settings as a practical extension of the physical examination.

Relationships between QT interval and heart rate variability at rest and the covariates in healthy young adults.

PubMed

Arai, Kaori; Nakagawa, Yui; Iwata, Toyoto; Horiguchi, Hyogo; Murata, Katsuyuki

2013-01-01

To clarify the links between ECG QT-related parameters and heart rate variability (HRV) and the covariates possibly distorting them, the averaged RR and QT intervals in a single lead ECG were measured for 64 male and 86 female subjects aged 18-26. The QT index, defined by Rautaharju et al., in the young adults was not significantly related to any HRV parameters nor heart rate, but the Bazett's corrected QT (QTc) interval was associated negatively with the parasympathetic activity and positively with heart rate. No significant differences in the QTc interval, QT index or heart rate were seen between the men and women, but they significantly differed between both sexes after adjustment for possible covariates such as age and body mass index (BMI). Significant sex differences in parasympathetic parameters of the HRV were unchanged before and after the adjustment, but significant differences observed in the unadjusted sympathetic parameters disappeared after adjusting for covariates. Age, BMI and body fat percentage also were significant covariates affecting these ECG parameters. Consequently, QT index, unaffected by heart rate and HRV parameters, appears to be a more useful indicator than the QTc interval. Instead, the QT index and HRV parameters are recommended to be simultaneously measured in epidemiological research because they are probably complementary in assessing autonomic nervous function. Also, these parameters should be analyzed in men and women separately. Copyright © 2012 Elsevier B.V. All rights reserved.

Spatial analysis of community-onset Staphylococcus aureus bacteremia in Queensland, Australia.

PubMed

Marquess, John; Hu, Wenbiao; Nimmo, Graeme R; Clements, Archie C A

2013-03-01

To investigate and describe the relationship between indigenous Australian populations, residential aged care services, and community-onset Staphylococcus aureus bacteremia (SAB) among patients admitted to public hospitals in Queensland, Australia. Ecological study. We used administrative healthcare data linked to microbiology results from patients with SAB admitted to Queensland public hospitals from 2005 through 2010 to identify community-onset infections. Data about indigenous Australian population and residential aged care services at the local government area level were obtained from the Queensland Office of Economic and Statistical Research. Associations between community-onset SAB and indigenous Australian population and residential aged care services were calculated using Poisson regression models in a Bayesian framework. Choropleth maps were used to describe the spatial patterns of SAB risk. We observed a 21% increase in relative risk (RR) of bacteremia with methicillin-susceptible S. aureus (MSSA; RR, 1.21 [95% credible interval, 1.15-1.26]) and a 24% increase in RR with nonmultiresistant methicillin-resistant S. aureus (nmMRSA; RR, 1.24 [95% credible interval, 1.13-1.34]) with a 10% increase in the indigenous Australian population proportion. There was no significant association between RR of SAB and the number of residential aged care services. Areas with the highest RR for nmMRSA and MSSA bacteremia were identified in the northern and western regions of Queensland. The RR of community-onset SAB varied spatially across Queensland. There was increased RR of community-onset SAB with nmMRSA and MSSA in areas of Queensland with increased indigenous population proportions. Additional research should be undertaken to understand other factors that increase the risk of infection due to this organism.

Dietary and supplemental calcium intakes in relation to mortality from cardiovascular diseases in the NIH-AARP Diet and Health Study

PubMed Central

Xiao, Qian; Murphy, Rachel A; Houston, Denise K.; Harris, Tamara B.; Chow, Wong-Ho; Park, Yikyung

2013-01-01

Background Calcium intake has been promoted due to its proposed benefit on bone health, particularly among the older population. However, concerns have been raised about the potential adverse effect of high calcium intake on cardiovascular health. Methods Dietary and supplemental calcium intakes were assessed at baseline (1995–96) in 388,229 men and women aged 50–71 years in the National Institutes of Health (NIH)–AARP Diet and Health Study. Supplemental calcium intake included calcium from multivitamins and individual calcium supplements. Cardiovascular disease (CVD) deaths were ascertained using the National Death Index. Multivariate Cox Proportional hazard models adjusted for demographic, lifestyle and dietary variables were used to estimate relative risks (RRs) and 95% confidence intervals (CIs). Results During an average of 12 years of follow-up, 7904 and 3874 CVD deaths in men and women, respectively, were identified. Supplements containing calcium were used by 51% of men and 70% of women. In men supplemental calcium intake was associated with an elevated risk of CVD death (RR>1000 vs. 0 mg/day =1.20, 95% CI: 1.05–1.36), more specifically with heart disease death (RR=1.19, 95% CI: 1.03–1.37), but not significantly with cerebrovascular disease death (RR=1.14, 95% CI: 0.81–1.61). In women, supplemental calcium intake was not associated with CVD death (RR= 1.06, 95% CI: 0.96, 1.18), heart disease death (RR=1.05, 95% CI: 0.93–1.18) or cerebrovascular disease death (RR=1.08, 95% CI: 0.87–1.33). Dietary calcium intake was not related to CVD death in either men or women. Conclusion Our finding suggests that high intake of supplemental calcium is associated with an excess risk of CVD death in men, but not in women. Additional studies are needed to investigate the effect of supplemental calcium use beyond bone health. PMID:23381719

Male infertility in long-term survivors of pediatric cancer: A report from the Childhood Cancer Survivor Study

PubMed Central

Wasilewski-Masker, K; Seidel, K D; Leisenring, W; Mertens, A C; Shnorhavorian, M; Ritenour, C W; Stovall, M; Green, D M; Sklar, C A; Armstrong, G T; Robison, L L; Meacham, L R

2014-01-01

Purpose The purpose of this study was to assess the prevalence of male infertility and treatment-related risk factors in childhood cancer survivors. Methods Within the Childhood Cancer Survivor Study, 1622 survivors and 274 siblings completed the Male Health Questionnaire. The analysis was restricted to survivors (938/1622; 57.8%) and siblings (174/274; 63.5%) who tried to become pregnant. Relative risks (RR) and 95% confidence intervals (CI) for the prevalence of self-reported infertility were calculated using generalized linear models for demographic variables and treatment-related factors to account for correlation among survivors and siblings of the same family. All statistical tests were two-sided. Results Among those who provided self-report data, the prevalence of infertility was 46.0% in survivors versus 17.5% in siblings (RR=2.64, 95% CI 1.88-3.70, p < 0.001). Of survivors who met the definition for infertility, 37% had reported at least one pregnancy with a female partner that resulted in a live birth. In a multivariable analysis, risk factors for infertility included an alkylating agent dose score (AAD) ≥ 3 (RR= 2.13, 95% CI 1.69-2.68 for AAD ≥ 3 versus AAD<3), surgical excision of any organ of the genital tract (RR=1.63, 95% CI 1.20-2.21), testicular radiation ≥ 4Gy (RR=1.99, 95% CI 1.52-2.61), and exposure to bleomycin (RR=1.55, 95% CI 1.20-2.01). Conclusion Many survivors who experience infertility father their own children suggesting episodes of both fertility and infertility. This and the novel association of infertility with bleomycin warrant further investigation. Implications for Cancer Survivors Though infertility is common, male survivors reporting infertility often father their own children. Bleomycin may pose some fertility risk. PMID:24711092

Amnioinfusion for preterm premature rupture of membranes.

PubMed

Hofmeyr, G Justus; Essilfie-Appiah, George; Lawrie, Theresa A

2011-12-07

Preterm premature rupture of membranes (PPROM) is a leading cause of perinatal morbidity and mortality. Amnioinfusion aims to restore amniotic fluid volume by infusing a solution into the uterine cavity. The objective of this review was to assess the effects of amnioinfusion for PPROM on perinatal and maternal morbidity and mortality. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2011). Randomised trials of amnioinfusion compared to no amnioinfusion in women with PPROM. Three review authors independently assessed trials for inclusion. Two review authors independently assessed trial quality and extracted data. Data were checked for accuracy. We included five trials but we only analysed data from four studies (with a total of 241 participants). One trial did not contribute any data to the review.Transcervical amnioinfusion improved fetal umbilical artery pH at delivery (mean difference 0.11; 95% confidence interval (CI) 0.08 to 0.14; one trial, 61 participants) and reduced persistent variable decelerations during labour (risk ratio (RR) 0.52; 95% CI 0.30 to 0.91; one trial, 86 participants).Transabdominal amnioinfusion was associated with a reduction in neonatal death (RR 0.30; 95% CI 0.14 to 0.66; two trials, 94 participants), neonatal sepsis (RR 0.26, 95% CI 0.11 to 0.61; one trial, 60 participants), pulmonary hypoplasia (RR 0.22; 95% CI 0.06 to 0.88; one trial, 34 participants) and puerperal sepsis (RR 0.20; 95% CI 0.05 to 0.84; one trial, 60 participants). Women in the amnioinfusion group were also less likely to deliver within seven days of membrane rupture (RR 0.18; 95% CI 0.05 to 0.70; one trial, 34 participants). These results should be treated with circumspection as the positive findings were mainly due to one trial with unclear allocation concealment. These results are encouraging but are limited by the sparse data and unclear methodological robustness, therefore further evidence is required before amnioinfusion for PPROM can be recommended for routine clinical practice.

Job Loss, Unemployment and the Incidence of Hazardous Drinking during the Late 2000s Recession in Europe among Adults Aged 50-64 Years.

PubMed

Bosque-Prous, Marina; Espelt, Albert; Sordo, Luis; Guitart, Anna M; Brugal, M Teresa; Bravo, Maria J

2015-01-01

To estimate the incidence of hazardous drinking in middle-aged people during an economic recession and ascertain whether individual job loss and contextual changes in unemployment influence the incidence rate in that period. Longitudinal study based on two waves of the SHARE project (Survey of Health, Ageing and Retirement in Europe). Individuals aged 50-64 years from 11 European countries, who were not hazardous drinkers at baseline (n = 7,615), were selected for this study. We estimated the cumulative incidence of hazardous drinking (≥40g and ≥20g of pure alcohol on average in men and women, respectively) between 2006 and 2012. Furthermore, in the statistical analysis, multilevel Poisson regression models with robust variance were fitted and obtained Risk Ratios (RR) and their 95% Confidence Intervals (95%CI). Over a 6-year period, 505 subjects became hazardous drinkers, with cumulative incidence of 6.6 per 100 persons between 2006 and 2012 (95%CI:6.1-7.2). Age [RR = 1.02 (95%CI:1.00-1.04)] and becoming unemployed [RR = 1.55 (95%CI:1.08-2.23)] were independently associated with higher risk of becoming a hazardous drinker. Conversely, having poorer self-perceived health was associated with lower risk of becoming a hazardous drinker [RR = 0.75 (95%CI:0.60-0.95)]. At country-level, an increase in the unemployment rate during the study period [RR = 1.32 (95%CI:1.17-1.50)] and greater increases in the household disposable income [RR = 0.97 (95%CI:0.95-0.99)] were associated with risk of becoming a hazardous drinker. Job loss among middle-aged individuals during the economic recession was positively associated with becoming a hazardous drinker. Changes in country-level variables were also related to this drinking pattern.

[Analysis of time domain and frequency domain heart rate variability in fighter pilot before and after upright tilt].

PubMed

Wang, L; Wu, L; Ji, G; Zhang, X; Chen, T; Wang, L

1998-12-01

Effects of upright tilt on mechanism of autonomic nervous regulation of cardiovascular system and characteristics of heart rate variability (HRV) were observed in sixty healthy male pilots. Relation between time domain and frequency domain indexes of short-time HRV (5 min) were analysed before and after upright tilt. The results showed that there are significant difference in short time HRV parameters before and after upright tilt. Significant relationship was formed between time domain and frequency domain indexes of HRV. It suggests that time domain and frequency domain HRV analysis is capable of revealing certain informations embedded in a short series of R-R intervals and can help to evaluate the status of autonomic regulation of cardiovascular function in pilots.

Complex character analysis of heart rate variability following brain asphyxia.

PubMed

Cai, Yuanyuan; Qiu, Yihong; Wei, Lan; Zhang, Wei; Hu, Sijun; Smith, Peter R; Crabtree, Vincent P; Tong, Shanbao; Thakor, Nitish V; Zhu, Yisheng

2006-05-01

In the present study Renyi entropy and L-Z complexity were used to characterize heart rate variability (HRV) of rats that were suffered from brain asphyxia and ischemia. Two groups of rats were studied: (a) rats (n=5) injected with NAALADase inhibitor, 2-PMPA, which has been proven neuroprotective in asphyxia injury and (b) control subjects (n=5) without medication. Renyi entropy and L-Z complexity of the R-R intervals (RRI) at different experiment stages were investigated in the two groups. The results show that both measures indicate less injury and better recovery in the drug injection group. The dynamic change of 90 min RRI signal after the asphyxia was investigated. The sudden reduction of the two parameters shows their sensitivity to the asphyxia insult.

Phase Synchronization of Hemodynamic Variables at Rest and after Deep Breathing Measured during the Course of Pregnancy

PubMed Central

Papousek, Ilona; Roessler, Andreas; Hinghofer-Szalkay, Helmut; Lang, Uwe; Kolovetsiou-Kreiner, Vassiliki

2013-01-01

Background The autonomic nervous system plays a central role in the functioning of systems critical for the homeostasis maintenance. However, its role in the cardiovascular adaptation to pregnancy-related demands is poorly understood. We explored the maternal cardiovascular systems throughout pregnancy to quantify pregnancy-related autonomic nervous system adaptations. Methodology Continuous monitoring of heart rate (R-R interval; derived from the 3-lead electrocardiography), blood pressure, and thoracic impedance was carried out in thirty-six women at six time-points throughout pregnancy. In order to quantify in addition to the longitudinal effects on baseline levels throughout gestation the immediate adaptive heart rate and blood pressure changes at each time point, a simple reflex test, deep breathing, was applied. Consequently, heart rate variability and blood pressure variability in the low (LF) and high (HF) frequency range, respiration and baroreceptor sensitivity were analyzed in resting conditions and after deep breathing. The adjustment of the rhythms of the R-R interval, blood pressure and respiration partitioned for the sympathetic and the parasympathetic branch of the autonomic nervous system were quantified by the phase synchronization index γ, which has been adopted from the analysis of weakly coupled chaotic oscillators. Results Heart rate and LF/HF ratio increased throughout pregnancy and these effects were accompanied by a continuous loss of baroreceptor sensitivity. The increases in heart rate and LF/HF ratio levels were associated with an increasing decline in the ability to flexibly respond to additional demands (i.e., diminished adaptive responses to deep breathing). The phase synchronization index γ showed that the observed effects could be explained by a decreased coupling of respiration and the cardiovascular system (HF components of heart rate and blood pressure). Conclusions/Significance The findings suggest that during the course of pregnancy the individual systems become increasingly independent to meet the increasing demands placed on the maternal cardiovascular and respiratory system. PMID:23577144

Heart rate variability (HRV) in kidney failure: measurement and consequences of reduced HRV.

PubMed

Ranpuria, Reena; Hall, Martica; Chan, Chris T; Unruh, Mark

2008-02-01

A common cause of death in end-stage renal disease (ESRD) patients on dialysis is sudden cardiac death (SCD). Compared to the general population, the percentage of cardiovascular deaths that are attributed to SCD is higher in patients treated by dialysis. While coronary artery disease (CAD) is the predominant cause of SCD in dialysis patients, reduced heart rate variability (HRV) may play a role in the higher risk of SCD among other risk factors. HRV refers to beat-to-beat alterations in heart rate as measured by periodic variation in the R-R interval. HRV provides a non-invasive method for investigating autonomic input into the heart. It quantifies the amount by which the R-R interval or heart rate changes from one cardiac cycle to the next. The autonomic nervous system transmits impulses from the central nervous system to peripheral organs and is responsible for controlling the heart rate, blood pressure and respiratory activity. In normal individuals, without cardiac disease, the heart rate has a high degree of beat-to-beat variability. HRV fluctuates with respiration: it increases with inspiration and decreases with expiration and is primarily mediated by parasympathetic activity. HRV has been used to evaluate and quantify the cardiac risk associated with a variety of conditions including cardiac disorders, stroke, multiple sclerosis and diabetes. In this narrative review, we will examine the association between HRV and SCD. This report explains the measurement of HRV and the consequences of reduced HRV in the general population and dialysis patients. Lastly, this review will outline the possible use of HRV as a clinical predictor for SCD in the dialysis population. The current understanding of SCD based on HRV findings among the ESRD population support the use of more aggressive treatment of CAD; greater use of angiotensin converting enzyme inhibitor (ACE-i)/angiotensin receptor blockers (ARBs) and beta-blockers and more frequent and/or nocturnal haemodialysis to improve the survival of a patient with kidney failure.

Ambient particulate air pollution, heart rate variability, and blood markers of inflammation in a panel of elderly subjects.

PubMed Central

Pope, C Arden; Hansen, Matthew L; Long, Russell W; Nielsen, Karen R; Eatough, Norman L; Wilson, William E; Eatough, Delbert J

2004-01-01

Epidemiologic studies report associations between particulate air pollution and cardiopulmonary morbidity and mortality. Although the underlying pathophysiologic mechanisms remain unclear, it has been hypothesized that altered autonomic function and pulmonary/systemic inflammation may play a role. In this study we explored the effects of air pollution on autonomic function measured by changes in heart rate variability (HRV) and blood markers of inflammation in a panel of 88 elderly subjects from three communities along the Wasatch Front in Utah. Subjects participated in multiple sessions of 24-hr ambulatory electrocardiographic monitoring and blood tests. Regression analysis was used to evaluate associations between fine particulate matter [aerodynamic diameter less than or equal to 2.5 microm (PM2.5)] and HRV, C-reactive protein (CRP), blood cell counts, and whole blood viscosity. A 100- microg/m3 increase in PM2.5 was associated with approximately a 35 (SE = 8)-msec decline in standard deviation of all normal R-R intervals (SDNN, a measure of overall HRV); a 42 (SE = 11)-msec decline in square root of the mean of the squared differences between adjacent normal R-R intervals (r-MSSD, an estimate of short-term components of HRV); and a 0.81 (SE = 0.17)-mg/dL increase in CRP. The PM2.5-HRV associations were reasonably consistent and statistically robust, but the CRP association dropped to 0.19 (SE = 0.10) after excluding the most influential subject. PM2.5 was not significantly associated with white or red blood cell counts, platelets, or whole-blood viscosity. Most short-term variability in temporal deviations of HRV and CRP was not explained by PM2.5; however, the small statistically significant associations that were observed suggest that exposure to PM2.5 may be one of multiple factors that influence HRV and CRP. PMID:14998750

ECG R-R peak detection on mobile phones.

PubMed

Sufi, F; Fang, Q; Cosic, I

2007-01-01

Mobile phones have become an integral part of modern life. Due to the ever increasing processing power, mobile phones are rapidly expanding its arena from a sole device of telecommunication to organizer, calculator, gaming device, web browser, music player, audio/video recording device, navigator etc. The processing power of modern mobile phones has been utilized by many innovative purposes. In this paper, we are proposing the utilization of mobile phones for monitoring and analysis of biosignal. The computation performed inside the mobile phone's processor will now be exploited for healthcare delivery. We performed literature review on RR interval detection from ECG and selected few PC based algorithms. Then, three of those existing RR interval detection algorithms were programmed on Java platform. Performance monitoring and comparison studies were carried out on three different mobile devices to determine their application on a realtime telemonitoring scenario.

Increase in Ischemic Stroke Incident Hospitalizations Among Bedouin Arabs During Ramadan Month.

PubMed

Zimhony, Noa; Abu-Salameh, Ibrahim; Sagy, Iftach; Dizitzer, Yotam; Oxman, Liat; Yitshak-Sade, Maayan; Novack, Victor; Horev, Anat; Ifergane, Gal

2018-05-03

Previous studies have not shown any significant effect on stroke incidence during Ramadan. We aimed to investigate the association between ischemic stroke incident hospitalizations and Ramadan, accounting for seasonality and temperature. This retrospective cohort study included all patients admitted with acute ischemic stroke to Soroka University Medical Center from June 2012 to June 2016. We obtained daily mean temperatures and relative humidity rates from 2 monitoring stations in South Israel. We analyzed the association between stroke incidence and Ramadan month, adjusting for weekly temperature and seasonality using Poisson regression models. We compared the first versus the last Ramadan fortnight. We performed an effect specificity analysis by assessing stroke incidence in the non-Bedouin population. We identified 4727 cases of ischemic stroke, 564 cases of which were Bedouin Arabs. Fifty-one cases occurred during Ramadan. Ramadan was significantly associated with an increased risk for ischemic stroke (RR 1.48; 95% confidence interval, 1.04-2.09), mainly during the first fortnight (RR 1.73, 95% confidence interval, 1.13-2.66) when compared with non-Ramadan periods. Mean weekly temperatures and the summer season were not associated with stroke incidence among Bedouin Arabs (RR 0.98; 95% confidence interval, 0.82-1.18 and RR 0.77; confidence interval 0.56-1.06 accordingly). Such association was not observed in the non-Bedouin population. The Ramadan month, particularly in its first 2 weeks, is an independent and ethnicity specific risk factor for ischemic stroke hospitalizations among the Bedouin Arab fasting population. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

[Polar S810 as an alternative resource to the use of the electrocardiogram in the 4-second exercise test].

PubMed

Pimentel, Alan Santos; Alves, Eduardo da Silva; Alvim, Rafael de Oliveira; Nunes, Rogério Tasca; Costa, Carlos Magno Amaral; Lovisi, Júlio Cesar Moraes; Perrout de Lima, Jorge Roberto

2010-05-01

The 4-second exercise test (T4s) evaluates the cardiac vagal tone during the initial heart rate (HR) transient at sudden dynamic exercise, through the identification of the cardiac vagal index (CVI) obtained from the electrocardiogram (ECG). To evaluate the use of the Polar S810 heart rate monitor (HRM) as an alternative resource to the use of the electrocardiogram in the 4-second exercise test. In this study, 49 male individuals (25 +/- 20 years, 176 +/-12 cm, 74 +/- 6 kg) underwent the 4-second exercise test. The RR intervals were recorded simultaneously by ECG and HRM. We calculated the mean and the standard deviation of the last RR interval of the pre-exercise period, or of the first RR interval of the exercise period, whichever was longer (RRB), of the shortest RR interval of the exercise period (RRC), and of the CVI obtained by ECG and HRM. We used the Student t-test for dependent samples (p < or 0.05) to test the significance of the differences between means. To identify the correlation between the ECG and the HRM, we used the linear regression to calculate the Pearson's correlation coefficient and the strategy proposed by Bland and Altman. Linear regression showed r(2) of 0.9999 for RRB, 0.9997 for RRC, and 0.9996 for CVI. Bland e Altman strategy presented standard deviation of 0.92 ms for RRB, 0.86 ms for RRC, and 0.002 for CVI. Polar S810 HRM was more efficient in the application of T4s compared to the ECG.

Modified carotid sinus massage using an ultrasonography for maximizing vagal tone: a crossover simulation study.

PubMed

Ha, Seung Min; Cho, Young Suk; Cho, Gyu Chong; Jo, Choong Hyun; Ryu, Ji Young

2015-07-01

The aim of this study was to ascertain if a modified carotid sinus massage (CSM) using ultrasonography is superior to the conventional CSM for vagal tone generation. This was a prospective, crossover, clinical trial including 30 subjects with sinus rhythm. Participants were paired, and they performed 2 types of CSM to each other. To perform the conventional technique, pressure was exerted at the point where the maximal impulse of the carotid pulse was palpated. In the modified technique, participants localized the point of maximal diameter just above the bifurcation of the common carotid artery using ultrasonography and applied pressure to that point. Mean differences between premaneuver and postmaneuver R-R intervals and heart rates were compared. The distance from the midline of the neck (x distance) to the angle of the mandible (y distance) was measured, and the mean distance between the 2 techniques was compared. The baseline mean premaneuver R-R interval and heart rate did not differ significantly between the 2 techniques. The postmaneuver R-R interval and heart rate as well as the mean R-R interval and heart rate differences were significantly greater in the modified CSM. The mean location determined using the modified CSM was located 0.8 cm lateral and 0.8 cm superior to the mean location of the conventional CSM. The modified CSM using ultrasonography might be more useful than the conventional CSM in reverting episodes of paroxysmal supraventricular tachycardia and may be a suitable alternative for treating the same in the emergency department. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

HST Snapshot Study of Variable Stars in Globular Clusters: Inner Region of NGC 6441

NASA Technical Reports Server (NTRS)

Pritzl, Barton J.; Smith, Horace A.; Stetson, Peter B.; Catelan, Marcio; Sweigart, Allen V.; Layden, Andrew C.; Rich, R. Michael

2003-01-01

We present the results of a Hubble Space Telescope snapshot program to survey the inner region of the metal-rich globular cluster NGC 6441 for its variable stars. A total of 57 variable stars was found including 38 RR Lyrae stars, 6 Population II Cepheids, and 12 long period variables. Twenty-four of the RR Lyrae stars and all of the Population II Cepheids were previously undiscovered in ground-based surveys. Of the RR Lyrae stars observed in h s survey, 26 are pulsating in the fundamental mode with a mean period of 0.753 d and 12 are first-overtone mode pulsators with a mean period of 0.365 d. These values match up very well with those found in ground-based surveys. Combining all the available data for NGC 6441, we find mean periods of 0.759 d and 0.375 d for the RRab and RRc stars, respectively. We also find that the RR Lyrae in this survey are located in the same regions of a period-amplitude diagram as those found in ground-based surveys. The overall ratio of RRc to total RR Lyrae is 0.33. Although NGC 6441 is a metal-rich globular cluster and would, on that ground, be expected either to have few RR Lyrae stars, or to be an Oosterhoff type I system, its RR Lyrae more closely resemble those in Oosterhoff type II globular clusters. However, even compared to typical Oosterhoff type II systems, the mean period of its RRab stars is unusually long. We also derived I-band period-luminosity relations for the RR Lyrae stars. Of the six Population II Cepheids, five are of W Virginis type and one is a BL Herculis variable star. This makes NGC 6441, along with NGC 6388, the most metal-rich globular cluster known to contain these types of variable stars. Another variable, V118, may also be a Population II Cepheid given its long period and its separation in magnitude from the RR Lyrae stars. We examine the period-luminosity relation for these Population II Cepheids and compare it to those in other globular clusters and in the Large Magellanic Cloud. We argue that there does not appear to be a change in the period-luminosity relation slope between the BL Herculis and W Virginis stars, but that a change of slope does occur when the RV Tauri stars are added to the period-luminosity relation.

The Optical Gravitational Lensing Experiment: Analysis of the Bulge RR Lyrae Population from the OGLE-III Data

NASA Astrophysics Data System (ADS)

Pietrukowicz, P.; Udalski, A.; Soszyński, I.; Nataf, D. M.; Wyrzykowski, Ł.; Poleski, R.; Kozłowski, S.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Ulaczyk, K.

2012-05-01

We have analyzed the data on 16,836 RR Lyrae (RR Lyr) variables observed toward the Galactic bulge during the third phase of the Optical Gravitational Lensing Experiment (OGLE-III), which took place in 2001-2009. Using these standard candles, we show that the ratio of total-to-selective extinction toward the bulge is given by RI = AI /E(V - I) = 1.080 ± 0.007 and is independent of color. We demonstrate that the bulge RR Lyr stars form a metal-uniform population, slightly elongated in its inner part. The photometrically derived metallicity distribution is sharply peaked at [Fe/H] = -1.02 ± 0.18, with a dispersion of 0.25 dex. In the inner regions (|l| < 3°, |b| < 4°) the RR Lyr tend to follow the barred distribution of the bulge red clump giants. The distance to the Milky Way center inferred from the bulge RR Lyr is R 0 = 8.54 ± 0.42 kpc. We report a break in the mean density distribution at a distance of ~0.5 kpc from the center indicating its likely flattening. Using the OGLE-III data, we assess that (4-7) × 104 type ab RR Lyr variables should be detected toward the bulge area of the ongoing near-IR VISTA Variables in the Via Lactea (VVV) survey, where the uncertainty partially results from the unknown RR Lyr spatial density distribution within 0.2 kpc from the Galactic center.

Fetal electrocardiographic measurements in the assessment of fetal heart rate variability in the antepartum period.

PubMed

Van Leeuwen, Peter; Werner, Lisa; Hilal, Ziad; Schiermeier, Sven; Hatzmann, Wolfgang; Grönemeyer, Dietrich

2014-03-01

This study examines signal availability in fetal electrocardiogram (FECG) beat-to-beat acquisition and the accuracy of fetal heart rate variability (HRV) analysis in the clinical setting using a commercially available FECG monitor. Signal availability was examined in 130 FECG recordings of 0.3-17.5 h duration collected in 63 fetuses (25th-42nd week of gestation) under uncontrolled conditions. Identification of R-peaks demonstrated a signal loss of 30% ± 24% with 3.6 ± 1.7 signal gaps per minute. Median duration of the gaps within a recording was 1.8 ± 0.2 s. Per hour of recording, 1.8 ± 2.1 episodes of 5 min of uninterrupted data were found. Signal availability improved with gestational age and was poorer in women with high body-mass index. Fetal HRV between weeks 36-42 was examined on the basis of 5 min RR-interval episodes obtained under controlled quiet conditions in 55 FECG compared to 46 high quality fetal magnetocardiograms. There were no differences in RR-interval duration, its standard deviation and low frequency power. However, various measures of short-term HRV were significantly higher in the FECG data: root mean square of successive differences (10.0 ± 1.8 versus 6.6 ± 3.0 ms, p < 0.001, high frequency spectral power (24 ± 12 versus 13 ± 13 ms(2), p < 0.001) and approximate entropy (0.86 ± 0.16 versus 0.73 ± 0.24, p = 0.007). We conclude that, in spite of considerable signal loss, FECG recordings can accurately estimate heart rate and its overall variance. However, measures that quantify short-term beat-to-beat HRV will be compromised due to possible recurring inappropriate detection of single R-peaks.

Skin denervation and its clinical significance in late-stage chronic kidney disease.

PubMed

Chao, Chi-Chao; Wu, Vin-Cent; Tan, Chun-Hsiang; Wang, Yi-Mei; Tseng, Ming-Tsung; Wu, Pei-Chen; Lin, Yea-Huey; Lin, Whei-Min; Wu, Kwan-Dun; Hsieh, Sung-Tsang

2011-02-01

To investigate the skin innervation and its clinical significance in late-stage chronic kidney disease (CKD). Case series. National Taiwan University Hospital, Taipei, Taiwan. Forty consecutive nondiabetic patients with late-stage CKD (14 female and 26 male; mean [SD] age, 60.7 [12.3] years), including 2 cases with stage 3 CKD, 6 with stage 4 CKD, and 32 with stage 5 CKD, ie, end-stage kidney disease. Clinical evaluation of neurological deficits, nerve conduction study, autonomic function tests, and a 3-mm-diameter skin biopsy specimen taken from the distal leg. Quantitation of epidermal innervation, parameters of nerve conduction study, R-R interval variability, and sympathetic skin response. Clinically, 21 patients (52.5%) were symptomatic with paresthesia over the limbs or autonomic symptoms. The intraepidermal nerve fiber (IENF) density was markedly reduced in patients with CKD compared with age- and sex-matched controls (mean [SD], 2.8 [2.0] vs 8.6 [2.8] fibers/mm; P < .001). Skin denervation was observed in 27 patients (67.5%). Fifteen patients (37.5%) had abnormalities on nerve conduction studies, and 29 patients (72.5%) had abnormal results on autonomic function tests. By analysis with multiple regression models, the IENF density was negatively correlated with the duration of renal disease (P = .02). Additionally, the R-R interval variability at rest was linearly correlated with the IENF density (P = .02) and the absence of sympathetic skin responses at the soles was associated with reduced IENF density (P = .03). Small-fiber sensory and autonomic neuropathies constitute the major form of neuropathy in late-stage CKD. Furthermore, skin denervation was associated with the duration of renal disease.

Favorable effects of carotid endarterectomy on baroreflex sensitivity and cardiovascular neural modulation: a 4-month follow-up.

PubMed

Dalla Vecchia, Laura; Barbic, Franca; Galli, Andrea; Pisacreta, Massimo; Gornati, Rosella; Porretta, Tiziano; Porta, Alberto; Furlan, Raffaello

2013-06-15

Carotid surgery variably modifies carotid afferent innervation, thus affecting arterial baroreceptor sensitivity. Low arterial baroreflex sensitivity is a well-known independent risk factor for cardiovascular diseases. The aim of this study was to assess the 4-mo effects of carotid endarterectomy (CEA) on arterial baroreceptor sensitivity and cardiovascular autonomic profile in patients with unilateral carotid stenosis. We enrolled 20 patients (72 ± 8 yr) with unilateral >70% carotid stenosis. ECG, beat-by-beat blood pressure, and respiration were continuously recorded before and 126 ± 9 days after CEA, at rest and during a 75° head-up tilt. Both pharmacological (modified Oxford technique, BRS) and spontaneous (index α, spectral analysis) arterial baroreflex sensitivity were assessed. Cardiovascular autonomic profile was evaluated by plasma catecholamines and spectral indexes of cardiac sympathovagal modulation [low-frequency R-R interval (LFRR), low frequency-to high frequency ratio (LF/HF), high-frequency R-R interval (HFRR)] and sympathetic vasomotor control [low-frequency systolic arterial pressure (LFSAP)] obtained from heart rate and SAP variability. After CEA, both the index α and BRS were higher (P < 0.02) at rest. SAP variance decreased both at rest and during tilt (P < 0.02). Before surgery, tilt did not modify the autonomic profile compared with baseline. After CEA, tilt increased LF/HF and LFSAP and reduced HFRR compared with rest (P < 0.02). Four months after CEA was performed, arterial baroreflex sensitivity was enhanced. Accordingly, the patients' autonomic profile had shifted toward reduced cardiac and vascular sympathetic activation and enhanced cardiac vagal activity. The capability to increase cardiovascular sympathetic activation in response to orthostasis was restored. Baroreceptor sensitivity improvement might play an additional role in the more favorable outcome observed in patients after carotid surgery.

Heart Rate Variability Discriminates Competitive Levels in Professional Soccer Players.

PubMed

Proietti, Riccardo; di Fronso, Selenia; Pereira, Lucas A; Bortoli, Laura; Robazza, Claudio; Nakamura, Fabio Y; Bertollo, Maurizio

2017-06-01

Heart rate variability (HRV) has been increasingly used to monitor team sports athletes. Besides the traditional time domain indices (i.e., the SD of successive RR intervals [SDNN] and the root mean square difference of successive normal RR intervals [RMSSD]), recently the use of the stress score (SS), which is an inverse function of the SD2 index derived from the Poincaré plot, and the sympathetic/parasympathetic ratio (S/PS) to monitor soccer players has been proposed. However, the reliability of these new indices and the ability of HRV to differentiate between soccer competitive levels are unknown. The aim of this study was to analyze the reliability of the different HRV-derived indices in professional soccer players during the competitive period and to compare HRV of professional soccer players from 3 teams of distinct competitive levels (i.e., Italian Second Division [2D], European League [EL], and Champions League [CL]). Fifty-four male professional soccer players from 3 different teams of 2 European countries (Italy and Germany) participated in the study. The intraclass correlation coefficient values of the HRV indices varied from 0.78 (very large) to 0.90 (near perfect). The coefficient of variation (CV) values for RMSSD and SDNN were all <5.00%, although the CV for SS was 6.13% and for S/PS, it was 21.33%. Both the CL and EL groups, assumed to be internationally qualified, presented higher lnRMSSD and lnSDNN and lower lnSS and S/PS than the 2D. Therefore, the HRV can be considered reliable in professional soccer players and is able to differentiate between international- and national-level players.

Effect of Missing Inter-Beat Interval Data on Heart Rate Variability Analysis Using Wrist-Worn Wearables.

PubMed

Baek, Hyun Jae; Shin, JaeWook

2017-08-15

Most of the wrist-worn devices on the market provide a continuous heart rate measurement function using photoplethysmography, but have not yet provided a function to measure the continuous heart rate variability (HRV) using beat-to-beat pulse interval. The reason for such is the difficulty of measuring a continuous pulse interval during movement using a wearable device because of the nature of photoplethysmography, which is susceptible to motion noise. This study investigated the effect of missing heart beat interval data on the HRV analysis in cases where pulse interval cannot be measured because of movement noise. First, we performed simulations by randomly removing data from the RR interval of the electrocardiogram measured from 39 subjects and observed the changes of the relative and normalized errors for the HRV parameters according to the total length of the missing heart beat interval data. Second, we measured the pulse interval from 20 subjects using a wrist-worn device for 24 h and observed the error value for the missing pulse interval data caused by the movement during actual daily life. The experimental results showed that mean NN and RMSSD were the most robust for the missing heart beat interval data among all the parameters in the time and frequency domains. Most of the pulse interval data could not be obtained during daily life. In other words, the sample number was too small for spectral analysis because of the long missing duration. Therefore, the frequency domain parameters often could not be calculated, except for the sleep state with little motion. The errors of the HRV parameters were proportional to the missing data duration in the presence of missing heart beat interval data. Based on the results of this study, the maximum missing duration for acceptable errors for each parameter is recommended for use when the HRV analysis is performed on a wrist-worn device.

A statistical note on the redundancy of nine standard baroreflex parameters

NASA Technical Reports Server (NTRS)

Ludwig, David A.; Convertino, Victor A.

1991-01-01

An accepted method for measuring the responsiveness of the carotid-cardiac baroreflex to arterial pressure changes is to artificially stimulate the baroreceptors in the neck with a pressurized neck chamber. Nine physiological responses to this type of stimulation are quantified and used as indicators of the baroreflex response function. Thirty male humans between the ages of 27 and 46 underwent the carotid-cardiac baroreflex test. The data for the nine response parameters were analyzed by principle component factor analysis. The results indicated that 92.5 percent of the total variance across all nine parameters could be explained in four dimensions. The first two dimensions reflected location points for R-R interval and carotid distending pressure, respectively. The third factor was composed of measures reflecting the gain (responsiveness) of the reflex. The fourth dimension was the ratio of baseline R-R interval to the maximal R-R interval response during simulated hypertension. The data suggest that the analysis of all nine baroreflex parameters is likely to be redundant and researchers should account for these redundancies either in their analyses or conclusions.

Oral health of schoolchildren in Western Australia.

PubMed

Arrow, P

2016-09-01

The West Australian School Dental Service (SDS) provides free, statewide, primary dental care to schoolchildren aged 5-17 years. This study reports on an evaluation of the oral health of children examined during the 2014 calendar year. Children were sampled, based on their date of birth, and SDS clinicians collected the clinical information. Weighted mean values of caries experience were presented. Negative binomial regression modelling was undertaken to test for factors of significance in the rate of caries occurrence. Data from children aged 5-15 years were used (girls = 4616, boys = 4900). Mean dmft (5-10-year-olds), 1.42 SE 0.03; mean DMFT (6-15-year-olds), 0.51 SE 0.01. Negative binomial regression model of permanent tooth caries found higher rates of caries in children who were from non-fluoridated areas (RR 2.1); Aboriginal (RR 2.4); had gingival inflammation (RR 1.5); lower ICSEA level (RR 1.4); and recalled at more than 24-month interval (RR 1.8). The study highlighted poor dental health associated with living in non-fluoridated areas, Aboriginal identity, poor oral hygiene, lower socioeconomic level and having extended intervals between dental checkups. Timely assessments and preventive measures targeted at groups, including extending community water fluoridation, may assist in further improving the oral health of children in Western Australia. © 2015 Australian Dental Association.

Power law behavior of RR-interval variability in healthy middle-aged persons, patients with recent acute myocardial infarction, and patients with heart transplants

NASA Technical Reports Server (NTRS)

Bigger, J. T. Jr; Steinman, R. C.; Rolnitzky, L. M.; Fleiss, J. L.; Albrecht, P.; Cohen, R. J.

1996-01-01

BACKGROUND. The purposes of the present study were (1) to establish normal values for the regression of log(power) on log(frequency) for, RR-interval fluctuations in healthy middle-aged persons, (2) to determine the effects of myocardial infarction on the regression of log(power) on log(frequency), (3) to determine the effect of cardiac denervation on the regression of log(power) on log(frequency), and (4) to assess the ability of power law regression parameters to predict death after myocardial infarction. METHODS AND RESULTS. We studied three groups: (1) 715 patients with recent myocardial infarction; (2) 274 healthy persons age and sex matched to the infarct sample; and (3) 19 patients with heart transplants. Twenty-four-hour RR-interval power spectra were computed using fast Fourier transforms and log(power) was regressed on log(frequency) between 10(-4) and 10(-2) Hz. There was a power law relation between log(power) and log(frequency). That is, the function described a descending straight line that had a slope of approximately -1 in healthy subjects. For the myocardial infarction group, the regression line for log(power) on log(frequency) was shifted downward and had a steeper negative slope (-1.15). The transplant (denervated) group showed a larger downward shift in the regression line and a much steeper negative slope (-2.08). The correlation between traditional power spectral bands and slope was weak, and that with log(power) at 10(-4) Hz was only moderate. Slope and log(power) at 10(-4) Hz were used to predict mortality and were compared with the predictive value of traditional power spectral bands. Slope and log(power) at 10(-4) Hz were excellent predictors of all-cause mortality or arrhythmic death. To optimize the prediction of death, we calculated a log(power) intercept that was uncorrelated with the slope of the power law regression line. We found that the combination of slope and zero-correlation log(power) was an outstanding predictor, with a relative risk of > 10, and was better than any combination of the traditional power spectral bands. The combination of slope and log(power) at 10(-4) Hz also was an excellent predictor of death after myocardial infarction. CONCLUSIONS. Myocardial infarction or denervation of the heart causes a steeper slope and decreased height of the power law regression relation between log(power) and log(frequency) of RR-interval fluctuations. Individually and, especially, combined, the power law regression parameters are excellent predictors of death of any cause or arrhythmic death and predict these outcomes better than the traditional power spectral bands.

The Search for RR Lyrae Variables in the Dark Energy Survey

NASA Astrophysics Data System (ADS)

Nielsen, Chandler; Marshall, Jennifer L.; Long, James

2017-01-01

RR Lyrae variables are stars with a characteristic relationship between magnitude and phase and whose distances can be easily determined, making them extremely valuable in mapping and analyzing galactic substructure. We present our method of searching for RR Lyrae variable stars using data extracted from the Dark Energy Survey (DES). The DES probes for stars as faint as i = 24.3. Finding such distant RR Lyrae allows for the discovery of objects such as dwarf spheroidal tidal streams and dwarf galaxies; in fact, at least one RR Lyrae has been discovered in each of the probed dwarf spheroidal galaxies orbiting the Milky Way (Baker & Willman 2015). In turn, these discoveries may ultimately resolve the well-known missing satellite problem, in which theoretical simulations predict many more dwarf satellites than are observed in the local Universe. Using the Lomb-Scargle periodogram to determine the period of the star being analyzed, we could display the relationship between magnitude and phase and visually determine if the star being analyzed was an RR Lyrae. We began the search in frequently observed regions of the DES footprint, known as the supernova fields. We then moved our search to known dwarf galaxies found during the second year of the DES. Unfortunately, we did not discover RR Lyrae in the probed dwarf galaxies; this method should be tried again once more observations are taken in the DES.

Colorectal cancer mortality and industrial pollution in Spain

PubMed Central

2012-01-01

Background Records kept as a result of the implementation of Integrated Pollution Prevention and Control (IPPC) and the European Pollutant Release and Transfer Register (E-PRTR) constitute a public inventory of industries, created by the European Commission, which is a valuable resource for monitoring industrial pollution. Our objective is to ascertain whether there might be excess colorectal cancer mortality among populations residing in the vicinity of Spanish industrial installations that are governed by the IPPC Directive and E-PRTR Regulation and report their emissions to air. Methods An ecological study was designed to examine colorectal cancer mortality at a municipal level (8098 Spanish towns), over the period 1997–2006. We conducted an exploratory "near vs. far" analysis to estimate the relative risks (RR) of towns situated at a distance of less than 2 km from industrial installations. The analysis was repeated for each of the 24 industrial groups. RR and their 95% credible/confidence intervals (95%CI) were estimated on the basis of Poisson regression models, using two types of modelling: a) the conditional autoregressive Bayesian model proposed by Besag, York and Mollié, with explanatory variables; and b) a mixed regression model. Integrated nested Laplace approximations were used as a Bayesian inference tool. Results Statistically significant RRs were detected in the vicinity of mining industry (RR 1.258; 95%CI 1.082 - 1.463), paper and wood production (RR 1.071; 95%CI 1.007 – 1.140), food and beverage sector (RR 1.069; 95%CI 1.029 - 1.111), metal production and processing installations (RR 1.065; 95% CI 1.011 – 1.123) and ceramics (RR 1.050 ; 95%CI 1.004 – 1.099). Conclusions Given the exploratory nature of this study, it would seem advisable to check in other countries or with other designs, if the proximity of industries that emit pollutants into the air could be an added risk factor for colorectal cancer mortality. Nevertheless, some of the differences between men and women observed in the analyses of the industrial groups suggest that there may be a component of occupational exposure, little-studied in the case of cancers of the digestive system. PMID:22852770

Balancing the efficacy and safety of misoprostol: a meta-analysis comparing 25 versus 50 micrograms of intravaginal misoprostol for the induction of labour.

PubMed

McMaster, K; Sanchez-Ramos, L; Kaunitz, A M

2015-03-01

The optimal dose of misoprostol for the induction of labour remains uncertain. To compare the efficacy and safety of 25 versus 50 micrograms of intravaginal misoprostol tablets for the induction of labour and cervical ripening. We performed electronic and manual searches to identify relevant randomised trials. The efficacy outcomes assessed were rates of vaginal delivery within 24 hours, delivery within one dose, and oxytocin augmentation, and interval to delivery. The safety outcomes assessed were incidences of tachysystole, hyperstimulation, caesarean delivery, cesarean delivery for non-reassuring fetal heart rate (FHR), operative vaginal delivery, abnormal 5-minute Apgar score, abnormal cord gas values, admission to a neonatal intensive care unit (NICU), and meconium passage. Thirteen studies (1945 women) were included. Relative risk (RR) and 95% confidence intervals (CI) were calculated using fixed-effects and random-effects models. We found that 25 micrograms was less efficacious, with lower rates of delivery after one dose (RR 0.59; 95% CI 0.39-0.88) and vaginal delivery within 24 hours (RR 0.88; 95% CI 0.79-0.96), and with increased rates of oxytocin augmentation (RR 1.54, 95% CI 1.36-1.75). We noted an improved safety profile with 25 micrograms, however, with decreased rates of tachysystole (RR 0.46; 95% CI 0.35-0.61), hyperstimulation (RR 0.5; 95% CI 0.31-0.78), caesarean deliveries for non-reassuring FHR (RR 0.67; 95% CI 0.52-0.87), NICU admissions (RR 0.63; 95% CI 0.4-0.98), and meconium passage (RR 0.65; 95% CI 0.45-0.96). Although 50 micrograms of intravaginal misoprostol may be more efficacious, safety concerns make the 25-microgram dose preferable. © 2014 Royal College of Obstetricians and Gynaecologists.

Within-Session Stability of Short-Term Heart Rate Variability Measurement

PubMed Central

2016-01-01

Abstract The primary aim of this study was to assess the retest stability of the short-term heart rate variability (HRV) measurement performed within one session and without the use of any intervention. Additionally, a precise investigation of the possible impact of intrinsic biological variation on HRV reliability was also performed. First, a single test-retest HRV measurement was conducted with 20-30 min apart from one another. Second, the HRV measurement was repeated in ten non-interrupted consecutive intervals. The lowest typical error (CV = 21.1%) was found for the square root of the mean squared differences of successive RR intervals (rMSSD) and the highest for the low frequency power (PLF) (CV = 93.9%). The standardized changes in the mean were trivial to small. The correlation analysis revealed the highest level for ln rMSSD (ICC = 0.87), while ln PLF represented the worst case (ICC = 0.59). The reliability indices for ln rMSSD in 10 consecutive intervals improved (CV = 9.9%; trivial standardized changes in the mean; ICC = 0.96). In conclusion, major differences were found in the reliability level between the HRV indices. The rMSSD demonstrated the highest reliability level. No substantial influence of intrinsic biological variation on the HRV reliability was observed. PMID:28149345

Effects of auditory stimulation with music of different intensities on heart period

PubMed Central

do Amaral, Joice A.T.; Guida, Heraldo L.; de Abreu, Luiz Carlos; Barnabé, Viviani; Vanderlei, Franciele M.; Valenti, Vitor E.

2015-01-01

Various studies have indicated that music therapy with relaxant music improves cardiac function of patients treated with cardiotoxic medication and heavy-metal music acutely reduces heart rate variability (HRV). There is also evidence that white noise auditory stimulation above 50 dB causes cardiac autonomic responses. In this study, we aimed to evaluate the acute effects of musical auditory stimulation with different intensities on cardiac autonomic regulation. This study was performed on 24 healthy women between 18 and 25 years of age. We analyzed HRV in the time [standard deviation of normal-to-normal RR intervals (SDNN), percentage of adjacent RR intervals with a difference of duration >50 ms (pNN50), and root-mean square of differences between adjacent normal RR intervals in a time interval (RMSSD)] and frequency [low frequency (LF), high frequency (HF), and LF/HF ratio] domains. HRV was recorded at rest for 10 minutes. Subsequently, the volunteers were exposed to baroque or heavy-metal music for 5 minutes through an earphone. The volunteers were exposed to three equivalent sound levels (60–70, 70–80, and 80–90 dB). After the first baroque or heavy-metal music, they remained at rest for 5 minutes and then they were exposed to the other music. The sequence of songs was randomized for each individual. Heavy-metal musical auditory stimulation at 80–90 dB reduced the SDNN index compared with control (44.39 ± 14.40 ms vs. 34.88 ± 8.69 ms), and stimulation at 60–70 dB decreased the LF (ms2) index compared with control (668.83 ± 648.74 ms2 vs. 392.5 ± 179.94 ms2). Baroque music at 60–70 dB reduced the LF (ms2) index (587.75 ± 318.44 ms2 vs. 376.21 ± 178.85 ms2). In conclusion, heavy-metal and baroque musical auditory stimulation at lower intensities acutely reduced global modulation of the heart and only heavy-metal music reduced HRV at higher intensities. PMID:26870675

Association between heart rhythm and cortical sound processing.

PubMed

Marcomini, Renata S; Frizzo, Ana Claúdia F; de Góes, Viviane B; Regaçone, Simone F; Garner, David M; Raimundo, Rodrigo D; Oliveira, Fernando R; Valenti, Vitor E

2018-04-26

Sound signal processing signifies an important factor for human conscious communication and it may be assessed through cortical auditory evoked potentials (CAEP). Heart rate variability (HRV) provides information about heart rate autonomic regulation. We investigated the association between resting HRV and CAEP. We evaluated resting HRV in the time and frequency domain and the CAEP components. The subjects remained at rest for 10 minutes for HRV recording, then they performed the CAEP examinations through frequency and duration protocols in both ears. Linear regression indicated that the amplitude of the N2 wave of the CAEP in the left ear (not right ear) was significantly influenced by standard deviation of normal-to-normal RR-intervals (17.7%) and percentage of adjacent RR-intervals with a difference of duration greater than 50 milliseconds (25.3%) time domain HRV indices in the frequency protocol. In the duration protocol and in the left ear the latency of the P2 wave was significantly influenced by low (LF) (20.8%) and high frequency (HF) bands in normalized units (21%) and LF/HF ratio (22.4%) indices of HRV spectral analysis. The latency of the N2 wave was significantly influenced by LF (25.8%), HF (25.9%) and LF/HF (28.8%). In conclusion, we promote the supposition that resting heart rhythm is associated with thalamo-cortical, cortical-cortical and auditory cortex pathways involved with auditory processing in the right hemisphere.

Effects of Age, Exercise Duration, and Test Conditions on Heart Rate Variability in Young Endurance Horses

PubMed Central

Younes, Mohamed; Robert, Céline; Barrey, Eric; Cottin, François

2016-01-01

Although cardiac recovery is an important criterion for ranking horses in endurance competitions, heart rate variability (HRV) has hardly ever been studied in the context of this equestrian discipline. In the present study, we sought to determine whether HRV is affected by parameters such as age, exercise duration and test site. Accordingly, HRV might be used to select endurance horses with the fastest cardiac recovery. The main objective of the present study was to determine the effects of age, exercise duration, and test site on HRV variables at rest and during exercise and recovery in young Arabian endurance horses. Over a 3-year period, 77 young Arabian horses aged 4–6 years performed one or more exercise tests (consisting of a warm-up, cantering at 22 km.h−1and a final 500 m gallop at full speed) at four different sites. Beat-to-beat RR intervals were continuously recorded and then analyzed (using a time-frequency approach) to determine the instantaneous HRV components before, during and after the test. At rest, the root-mean-square of successive differences in RR intervals (RMSSD) was higher in the 4-year-olds (54.4 ± 14.5 ms) than in the 5-or 6-year-olds (44.9 ± 15.5 and 49.1 ± 11.7 ms, respectively). During the first 15 min of exercise (period T), the heart rate (HR) and RMSSD decreased with age. In 6-year-olds, RMSSD decreased as the exercise duration increased (T: 3.0 ± 1.4 vs. 2T: 3.6 ± 2.2 vs. 3T: 2.8 ± 1.0). During recovery, RMSSD was negatively correlated with the cardiac recovery time (CRT) and the recovery heart rate (RHR; R = −0.56 and −0.53, respectively; p < 0.05). At rest and during exercise and recovery, RMSSD and several HRV variables differed significantly as a function of the test conditions. HRV in endurance horses appears to be strongly influenced by age and environmental factors (such as ambient temperature, ambient humidity, and track quality). Nevertheless, RMSSD can be used to select endurance horses with the fastest cardiac recovery. PMID:27199770

Infertility, infertility treatment, and achievement of pregnancy in female survivors of childhood cancer: a report from the Childhood Cancer Survivor Study cohort

PubMed Central

Barton, Sara E.; Najita, Julie S.; Ginsburg, Elizabeth S.; Leisenring, Wendy M.; Stovall, Marilyn; Weathers, Rita E.; Sklar, Charles A.; Robison, Leslie L.; Diller, Lisa

2013-01-01

Background Prior studies have documented decreased pregnancy rates and early menopause in female cancer survivors; however, infertility rates and reproductive interventions have not been studied. This study investigates infertility and time to pregnancy among female childhood cancer survivors, and analyzes treatment characteristics associated with infertility and subsequent pregnancy. Methods The Childhood Cancer Survivor Study (CCSS) is a cohort study including five-year cancer survivors from 26 institutions who were <21 years old at the time of diagnosis between January 1, 1970, and December 31, 1986, and a sibling control group. CCSS females ages 18–39 years reporting they had ever been sexually active (3,531 survivors and 1,366 female controls) were studied. Self-reported infertility, medical treatment for infertility, the time to first pregnancy in survivors and siblings, and the risk of infertility in survivors by demographic, disease, and treatment variables were analyzed. Findings Survivors had an increased risk of clinical infertility (>1 year of attempts at conception without success) compared to siblings which was most pronounced at early reproductive ages (≤24 years Relative Risk (RR)=2·92, 95% Confidence Interval (CI) 1·18–7·20; 25–29 years RR=1·61, 95% CI 1·05–2·48; 30–39 years RR=1·37, 95% CI 1·11–1·69). Despite being equally likely to seek treatment for infertility, survivors were less likely to be prescribed medication for treatment of infertility (RR=0·57, 95% CI 0·46–0·70). Increasing doses of uterine radiation and alkylating agent chemotherapy were most strongly associated with infertility. Although survivors had an increased time to pregnancy interval (p=0·032), 64·2% (292/455) with infertility achieved a pregnancy. Interpretation A more comprehensive understanding of infertility after cancer is critical for counseling and decision-making regarding future attempts at conception as well as fertility preservation. PMID:23856401

Respiratory modulation of human autonomic function on Earth.

PubMed

Eckberg, Dwain L; Cooke, William H; Diedrich, André; Biaggioni, Italo; Buckey, Jay C; Pawelczyk, James A; Ertl, Andrew C; Cox, James F; Kuusela, Tom A; Tahvanainen, Kari U O; Mano, Tadaaki; Iwase, Satoshi; Baisch, Friedhelm J; Levine, Benjamin D; Adams-Huet, Beverley; Robertson, David; Blomqvist, C Gunnar

2016-10-01

We studied healthy supine astronauts on Earth with electrocardiogram, non-invasive arterial pressure, respiratory carbon dioxide concentrations, breathing depth and sympathetic nerve recordings. The null hypotheses were that heart beat interval fluctuations at usual breathing frequencies are baroreflex mediated, that they persist during apnoea, and that autonomic responses to apnoea result from changes of chemoreceptor, baroreceptor or lung stretch receptor inputs. R-R interval fluctuations at usual breathing frequencies are unlikely to be baroreflex mediated, and disappear during apnoea. The subjects' responses to apnoea could not be attributed to changes of central chemoreceptor activity (hypocapnia prevailed); altered arterial baroreceptor input (vagal baroreflex gain declined and muscle sympathetic nerve burst areas, frequencies and probabilities increased, even as arterial pressure climbed to new levels); or altered pulmonary stretch receptor activity (major breathing frequency and tidal volume changes did not alter vagal tone or sympathetic activity). Apnoea responses of healthy subjects may result from changes of central respiratory motoneurone activity. We studied eight healthy, supine astronauts on Earth, who followed a simple protocol: they breathed at fixed or random frequencies, hyperventilated and then stopped breathing, as a means to modulate and expose to view important, but obscure central neurophysiological mechanisms. Our recordings included the electrocardiogram, finger photoplethysmographic arterial pressure, tidal volume, respiratory carbon dioxide concentrations and peroneal nerve muscle sympathetic activity. Arterial pressure, vagal tone and muscle sympathetic outflow were comparable during spontaneous and controlled-frequency breathing. Compared with spontaneous, 0.1 and 0.05 Hz breathing, however, breathing at usual frequencies (∼0.25 Hz) lowered arterial baroreflex gain, and provoked smaller arterial pressure and R-R interval fluctuations, which were separated by intervals that were likely to be too short and variable to be attributed to baroreflex physiology. R-R interval fluctuations at usual breathing frequencies disappear during apnoea, and thus cannot provide evidence for the existence of a central respiratory oscillation. Apnoea sets in motion a continuous and ever changing reorganization of the relations among stimulatory and inhibitory inputs and autonomic outputs, which, in our study, could not be attributed to altered chemoreceptor, baroreceptor, or pulmonary stretch receptor activity. We suggest that responses of healthy subjects to apnoea are driven importantly, and possibly prepotently, by changes of central respiratory motoneurone activity. The companion article extends these observations and asks the question, Might terrestrial responses to our 20 min breathing protocol find expression as long-term neuroplasticity in serial measurements made over 20 days during and following space travel? Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Characterization of Myocardial Repolarization Reserve in Adolescent Females With Anorexia Nervosa.

PubMed

Padfield, Gareth J; Escudero, Carolina A; DeSouza, Astrid M; Steinberg, Christian; Gibbs, Karen; Puyat, Joseph H; Lam, Pei Yoong; Sanatani, Shubhayan; Sherwin, Elizabeth; Potts, James E; Sandor, George; Krahn, Andrew D

2016-02-09

Patients with anorexia nervosa exhibit abnormal myocardial repolarization and are susceptible to sudden cardiac death. Exercise testing is useful in unmasking QT prolongation in disorders associated with abnormal repolarization. We characterized QT adaptation during exercise in anorexia. Sixty-one adolescent female patients with anorexia nervosa and 45 age- and sex-matched healthy volunteers performed symptom-limited cycle ergometry during 12-lead ECG monitoring. Changes in the QT interval during exercise were measured, and QT/RR-interval slopes were determined by using mixed-effects regression modeling. Patients had significantly lower body mass index than controls; however, resting heart rates and QT/QTc intervals were similar at baseline. Patients had shorter exercise times (13.7±4.5 versus 20.6±4.5 minutes; P<0.001) and lower peak heart rates (159±20 versus 184±9 beats/min; P<0.001). The mean QTc intervals were longer at peak exercise in patients (442±29 versus 422±19 ms; P<0.001). During submaximal exertion at comparable heart rates (114±6 versus 115±11 beats/min; P=0.54), the QTc interval had prolonged significantly more in patients than controls (37±28 versus 24±25 ms; P<0.016). The RR/QT slope, best described by a curvilinear relationship, was more gradual in patients than in controls (13.4; 95% confidence interval, 12.8-13.9 versus 15.8; 95% confidence interval, 15.3-16.4 ms QT change per 10% change in RR interval; P<0.001) and steepest in patients within the highest body mass index tertile versus the lowest (13.9; 95% confidence interval, 12.9-14.9 versus 12.3; 95% confidence interval, 11.3-13.3; P=0.026). Despite the absence of manifest QT prolongation, adolescent anorexic females have impaired repolarization reserve in comparison with healthy controls. Further study may identify impaired QT dynamics as a risk factor for arrhythmias in anorexia nervosa. © 2016 American Heart Association, Inc.

Heart rate and cardiovascular variability at high altitude.

PubMed

Bernardi, Luciano

2007-01-01

Primary effect of hypobaric hypoxia on the circulation is a direct vasodilatory effect on the peripheral circulation, which is normally prevented by a sympathetic-induced vasoconstriction. Most of the clinical methods for testing the baroreflex sensitivity only evaluate the cardiac-vagal branch of the baroreflex, but at altitude it is also of importance to test the vascular effects of the baroreflex. This is possible by directly measuring sympathetic efferent activity (by microneurography) or by directly stimulating the carotid baroreceptors (by the neck suction). By cyclical stimulation of the carotid baroreceptors, neck suction-synchronous reflex oscillations could be observed in a large number of signals, including RR interval, blood pressure, microcirculation, muscle sympathetic nerve activity. An increase in fluctuations at the same frequency of the stimulus was considered an evidence of the ability of the carotid baroreceptors to modulate a given physiological signal. The sinusoidal neck suction was set at 0.10 Hz (low-frequency stimulation), or to a frequency close to- but distinct from- the respiratory signal (0.20 Hz, high frequency stimulation, whereas respiration was fixed to 0.25 Hz). The method is noninvasive, without side effects connected to use of drugs, and evaluates both the response to the heart and to the blood pressure of the baroreflex. The altitude-induced sympathetic activation was evidenced in sea level natives by a decrease in RR interval, an increase in blood pressure and in the 0.1Hz components of cardiac and vascular signals. The arterial baroflex was active on RR interval and also in blood pressure, even during acute exposure to high altitude, thus indicating that it was counteracting and modulating the increase in sympathetic tone. Signs of exaggerated sympathetic activation were evident in subjects with severe acute mountain sickness, while successful therapy was associated with a restoration of autonomic modulation. Conversely, sympathetic activation was reduced( and baroflex enhanced) in himalayan high altitude natives. In conclusion, a comprehensive understanding of the mechanism taking place during the adaptation to high altitude requires a multisignal approach, also integrated with equipment designed to provide specific provocative tests, such as those necessary to measure the cardiorespiratory interactions.

Tocolysis for repeat external cephalic version in breech presentation at term: a randomised, double-blinded, placebo-controlled trial.

PubMed

Impey, Lawrence; Pandit, Meghana

2005-05-01

External cephalic version (ECV) reduces the incidence of breech presentation at term and caesarean section for non-cephalic births. Tocolytics may improve success rates, but are time consuming, may cause side effects and have not been proven to alter caesarean section rates. The aim of this trial was to determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt. To determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt. Randomised, double-blinded, placebo-controlled trial. UK teaching hospital. One hundred and twenty-four women with a breech presentation at term who had undergone an unsuccessful attempt at ECV. Relative risks with 95% confidence intervals for categorical variables and a t test for continuous variables. Analysis was by intention to treat. Incidence of cephalic presentation at delivery. Secondary outcomes were caesarean section and measures of neonatal and maternal morbidity. The use of tocolysis for a repeat attempt at ECV significantly increases the incidence of cephalic presentation at delivery (RR 3.21; 95% CI 1.23-8.39) and reduces the incidence of caesarean section (RR 0.33; 95% CI 0.14-0.80). The effects were most marked in multiparous women (RR for cephalic presentation at delivery 9.38; 95% CI 1.64-53.62). Maternal and neonatal morbidity remain unchanged. The use of tocolysis increases the success rate of repeat ECV and reduces the incidence of caesarean section. A policy of only using tocolysis where an initial attempt has failed leads to a relatively high success rate with minimum usage of tocolysis.

Exposure assessment and heart rate variability monitoring in workers handling titanium dioxide particles: a pilot study

NASA Astrophysics Data System (ADS)

Ichihara, Sahoko; Li, Weihua; Omura, Seiichi; Fujitani, Yuji; Liu, Ying; Wang, Qiangyi; Hiraku, Yusuke; Hisanaga, Naomi; Wakai, Kenji; Ding, Xuncheng; Kobayashi, Takahiro; Ichihara, Gaku

2016-03-01

Titanium dioxide (TiO2) particles are used for surface coating and in a variety of products such as inks, fibers, food, and cosmetics. The present study investigated possible respiratory and cardiovascular effects of TiO2 particles in workers exposed to this particle at high concentration in a factory in China. The diameter of particles collected on filters was measured by scanning electron microscopy. Real-time size-dependent particle number concentration was monitored in the nostrils of four workers using condensation particle counter and optical particle counter. Electrocardiogram was recorded using Holter monitors for the same four workers to record heart rate variability. Sixteen workers underwent assessment of the respiratory and cardiovascular systems. Mass-based individual exposure levels were also measured with personal cascade impactors. The primary particle diameter ranged from 46 to 562 nm. Analysis of covariance of the pooled data of the four workers showed that number of particles with a diameter <300 nm was associated positively with total number of N-N and negatively with total number of increase or decrease in successive RR intervals greater than 50 ms (RR50+/-) or percentage of RR 50+/- that were parameters of parasympathetic function. The total mass concentration was 9.58-30.8 mg/m3 during work, but significantly less before work (0.36 mg/m3). The clear abnormality in respiratory function was not observed in sixteen workers who had worked for 10 months to 13 years in the factory. The study showed that exposure to particles with a diameter <300 nm might affect HRV in workers handling TiO2 particles. The results highlight the need to investigate the possible impact of exposure to nano-scaled particles on the autonomic nervous system.

Efficacy of low-dose bupivacaine in spinal anaesthesia for Caesarean delivery: systematic review and meta-analysis.

PubMed

Arzola, C; Wieczorek, P M

2011-09-01

Spinal anaesthesia is the preferred anaesthetic technique for elective Caesarean deliveries. Hypotension is the most common side-effect and has both maternal and neonatal consequences. Different strategies have been attempted to prevent spinal-induced hypotension, including the use of low-dose bupivacaine. We conducted a systematic search for randomized controlled trials comparing the efficacy of spinal bupivacaine in low dose (LD ≤8 mg) with conventional dose (CD >8 mg) for elective Caesarean delivery. Thirty-five trials were identified for eligibility assessment, 15 were selected for data extraction, and 12 were finally included in the meta-analysis. We investigated sources of heterogeneity, subgroup analysis, and meta-regression for confounding variables (baricity, intrathecal opioids, lateral vs sitting position, uterine exteriorization, and study population). Sensitivity analysis was performed to test the robustness of the results. In the LD group, the need for analgesic supplementation during surgery was significantly higher [risk ratio (RR)=3.76, 95% confidence interval (95% CI)=2.38-5.92] and the number needed to treat for an additional harmful outcome (NNTH) was 4 (95% CI=2-7). Furthermore, the LD group exhibited a lower risk of hypotension (RR=0.78, 95% CI=0.65-0.93) and nausea/vomiting (RR=0.71, 95% CI=0.55-0.93). Conversion to general anaesthesia occurred only in the LD group (two events). Neonatal outcomes (Apgar score, acid-base status) and clinical quality variables (patient satisfaction, surgical conditions) showed non-significant differences between LD and CD. This meta-analysis demonstrates that low-dose bupivacaine in spinal anaesthesia compromises anaesthetic efficacy (risk of analgesic supplementation: high grade of evidence), despite the benefit of lower maternal side-effects (hypotension, nausea/vomiting: moderate grade of evidence).

Period Change Similarities Among the RR Lyrae Variables in Oosterhoff I and Oosterhoff II Globular Systems

NASA Astrophysics Data System (ADS)

Kunder, Andrea; Walker, Alistair; Stetson, Peter B.; Bono, Giuseppe; Nemec, James M.; de Propris, Roberto; Monelli, Matteo; Cassisi, Santi; Andreuzzi, Gloria; Dall'Ora, Massimo; Di Cecco, Alessandra; Zoccali, Manuela

2011-01-01

We present period change rates (dP/dt) for 42 RR Lyrae variables in the globular cluster IC 4499. Despite clear evidence of these period increases or decreases, the observed period change rates are an order of magnitude larger than predicted from theoretical models of this cluster. We find that there is a preference for increasing periods, a phenomenon observed in most RR Lyrae stars in Milky Way globular clusters. The period change rates as a function of position in the period-amplitude plane are used to examine possible evolutionary effects in OoI clusters, OoII clusters, field RR Lyrae stars, and the mixed-population cluster ω Centauri. It is found that there is no correlation between the period change rate and the typical definition of Oosterhoff groups. If the RR Lyrae period changes correspond with evolutionary effects, this would be in contrast to the hypothesis that RR Lyrae variables in OoII systems are evolved horizontal-branch stars that spent their zero-age horizontal-branch phase on the blue side of the instability strip. This may suggest that age may not be the primary explanation for the Oosterhoff types. Based in part on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility.

Autonomic cardiovascular modulation in masters and young cyclists following high-intensity interval training.

PubMed

Borges, Nattai R; Reaburn, Peter R; Doering, Thomas M; Argus, Christos K; Driller, Matthew W

2017-04-01

This study aimed at examining the autonomic cardiovascular modulation in well-trained masters and young cyclists following high-intensity interval training (HIT). Nine masters (age 55.6 ± 5.0 years) and eight young cyclists (age 25.9 ± 3.0 years) completed a HIT protocol of 6 x 30 sec at 175% of peak power output, with 4.5-min' rest between efforts. Immediately following HIT, heart rate and R-R intervals were monitored for 30-min during passive supine recovery. Autonomic modulation was examined by i) heart rate recovery in the first 60-sec of recovery (HRR 60 ); ii) the time constant of the 30-min heart rate recovery curve (HRRτ); iii) the time course of the root mean square for successive 30-sec R-R interval (RMSSD 30 ); and iv) time and frequency domain analyses of subsequent 5-min R-R interval segments. No significant between-group differences were observed for HRR 60 (P = 0.096) or HRR τ (P = 0.617). However, a significant interaction effect was found for RMSSD 30 (P = 0.021), with the master cyclists showing higher RMSSD 30 values following HIT. Similar results were observed in the time and frequency domain analyses with significant interaction effects found for the natural logarithm of the RMSSD (P = 0.008), normalised low-frequency power (P = 0.016) and natural logarithm of high-frequency power (P = 0.012). Following high-intensity interval training, master cyclists demonstrated greater post-exercise parasympathetic reactivation compared to young cyclists, indicating that physical training at older ages has significant effects on autonomic function.

Fasting insulin at baseline influences the number of cardiometabolic risk factors and R-R interval at 3years in a healthy population: the RISC Study.

PubMed

Pataky, Z; Golay, A; Laville, M; Disse, E; Mitrakou, A; Guidone, C; Gabriel, R; Bobbioni-Harsch, E

2013-09-01

This was a cross-sectional and longitudinal study of factors contributing to the number of cardiometabolic risk factors, common carotid artery intima-media thickness (CCA-IMT) and R-R interval in clinically healthy subjects without diabetes. Anthropometric and cardiometabolic parameters were measured in the Relationship between Insulin Sensitivity and Cardiovascular Disease (RISC) Study cohort at baseline (n=1211) and 3years later (n=974). At baseline, insulin sensitivity was assessed by the euglycaemic clamp technique. The CCA-IMT was echographically measured and the R-R interval was electrocardiographically evaluated at baseline and at the 3-year follow-up. Higher baseline BMI, fasting insulin and tobacco use as well as greater changes in BMI and fasting insulin but lower adiponectin levels, were associated with a greater number of cardiometabolic risk factors at the 3-year follow-up independently of insulin sensitivity (all P<0.02). The CCA-IMT increased with the number of cardiometabolic risk factors (P=0.008), but was not related to fasting insulin, whereas higher fasting insulinaemia and its 3-year changes were significantly associated with a smaller R-R interval (P=0.005 and P=0.002, respectively). These relationships were independent of baseline age, gender, BMI, adiponectin, insulin sensitivity, tobacco use and physical activity. In clinically healthy subjects, fasting insulinaemia, adiponectin and lifestyle parameters are related to the presence of one or two cardiometabolic risk factors before criteria for the metabolic syndrome are met. These results underline the importance of fasting insulinaemia as an independent cardiometabolic risk factor at an early stage of disease development in a healthy general population. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Prediction of paroxysmal atrial fibrillation using recurrence plot-based features of the RR-interval signal.

PubMed

Mohebbi, Maryam; Ghassemian, Hassan

2011-08-01

Atrial fibrillation (AF) is the most common cardiac arrhythmia and increases the risk of stroke. Predicting the onset of paroxysmal AF (PAF), based on noninvasive techniques, is clinically important and can be invaluable in order to avoid useless therapeutic intervention and to minimize risks for the patients. In this paper, we propose an effective PAF predictor which is based on the analysis of the RR-interval signal. This method consists of three steps: preprocessing, feature extraction and classification. In the first step, the QRS complexes are detected from the electrocardiogram (ECG) signal and then the RR-interval signal is extracted. In the next step, the recurrence plot (RP) of the RR-interval signal is obtained and five statistically significant features are extracted to characterize the basic patterns of the RP. These features consist of the recurrence rate, length of longest diagonal segments (L(max )), average length of the diagonal lines (L(mean)), entropy, and trapping time. Recurrence quantification analysis can reveal subtle aspects of dynamics not easily appreciated by other methods and exhibits characteristic patterns which are caused by the typical dynamical behavior. In the final step, a support vector machine (SVM)-based classifier is used for PAF prediction. The performance of the proposed method in prediction of PAF episodes was evaluated using the Atrial Fibrillation Prediction Database (AFPDB) which consists of both 30 min ECG recordings that end just prior to the onset of PAF and segments at least 45 min distant from any PAF events. The obtained sensitivity, specificity, positive predictivity and negative predictivity were 97%, 100%, 100%, and 96%, respectively. The proposed methodology presents better results than other existing approaches.

Determinants of contraceptive use and future contraceptive intentions of women attending child welfare clinics in urban Ghana.

PubMed

Wuni, Caroline; Turpin, Cornelius A; Dassah, Edward T

2017-08-01

Family planning is an integral component of maternal and child health services in Ghana. Although knowledge on contraception is universal and most women attend maternal and child health services, contraceptive use remains low among women after delivery. This study aimed to determine factors influencing current use and future contraceptive intentions of women who were attending child welfare clinics within 2 years of delivery in Sunyani Municipality, Ghana. We conducted an analytical cross-sectional study among mothers in six selected health care facilities. Data was collected on their socio-demographic characteristics, reproductive and contraceptive experiences and future contraceptive intentions. Categorical variables were compared using the chi-squared (χ 2 ) test. Factors associated with current use and future contraceptive intentions were determined using Poisson regression with a robust error variance to estimate crude and adjusted relative risks (RRs) with 95% confidence intervals (CIs). P < 0.1 was considered statistically significant. A total of 590 women were recruited into the study. Overall, 50.2% of the women were using contraception, 30.7% modern and 19.5% traditional methods. Compared to previous use, more women were using and would prefer the more effective contraceptive methods in future. Significant factors associated with current contraceptive use were, level of education (p = 0.02), discussing family planning during antenatal care (adjusted RR, 1.28; 95% CI, 1.07-1.53), or with one's partner (adjusted RR, 1.22; 95% CI, 1.01-1.47) and previous contraceptive use (adjusted RR, 1.91; 95% CI, 1.56-2.33). Family planning discussions during child welfare clinic (adjusted RR, 1.12; 95% CI, 0.99-1.26) or with one's spouse (adjusted RR, 1.20; 95% CI, 1.08-1.34), desire to space children (adjusted RR, 1.35; 95% CI, 1.17-1.55), previous (adjusted RR, 1.15; 95% CI, 1.05-1.27) and current (adjusted RR, 1.11; 95% CI, 1.01-1.22) contraceptive use were predictive of clients' intention to adopt family planning in the future. Effective counselling on family planning during antenatal and child welfare clinics, and encouraging spousal communication on contraception are likely to increase contraceptive use after delivery.

Risk and mortality of traumatic brain injury in stroke patients: two nationwide cohort studies.

PubMed

Chou, Yi-Chun; Yeh, Chun-Chieh; Hu, Chaur-Jong; Meng, Nai-Hsin; Chiu, Wen-Ta; Chou, Wan-Hsin; Chen, Ta-Liang; Liao, Chien-Chang

2014-01-01

Patients with stroke had higher incidence of falls and hip fractures. However, the risk of traumatic brain injury (TBI) and post-TBI mortality in patients with stroke was not well defined. Our study is to investigate the risk of TBI and post-TBI mortality in patients with stroke. Using reimbursement claims from Taiwan's National Health Insurance Research Database, we conducted a retrospective cohort study of 7622 patients with stroke and 30 488 participants without stroke aged 20 years and older as reference group. Data were collected on newly developed TBI after stroke with 5 to 8 years' follow-up during 2000 to 2008. Another nested cohort study including 7034 hospitalized patients with TBI was also conducted to analyze the contribution of stroke to post-TBI in-hospital mortality. Compared with the nonstroke cohort, the adjusted hazard ratio of TBI risk among patients with stroke was 2.80 (95% confidence interval = 2.58-3.04) during the follow-up period. Patients with stroke had higher mortality after TBI than those without stroke (10.2% vs 3.2%, P < .0001) with an adjusted relative risk (RR) of 1.46 (95% confidence interval = 1.15-1.84). Recurrent stroke (RR = 1.60), hemorrhagic stroke (RR = 1.68), high medical expenditure for stroke (RR = 1.80), epilepsy (RR = 1.79), neurosurgery (RR = 1.94), and hip fracture (RR = 2.11) were all associated with significantly higher post-TBI mortality among patients with stroke. Patients with stroke have an increased risk of TBI and in-hospital mortality after TBI. Various characteristics of stroke severity were all associated with higher post-TBI mortality. Special attention is needed to prevent TBI among these populations.

"J waves" induced after short coupling intervals: a manifestations of latent depolarization abnormality?

PubMed

Aizawa, Yoshifusa; Nakayama, Masafumi; Sato, Masahito; Okabe, Masaaki; Aizawa, Yoshiyasu; Takatsuki, Seiji; Fukuda, Keiichi

2017-04-24

To confirm the presence of tachycardia-induced slur or notch in the terminal portion of the QRS complexes in a general patient population. A tachycardia-induced J wave was defined as a slur or notch in the terminal portion of the QRS complexes newly induced at short RR intervals during atrial premature contractions (APCs) or atrial electrical stimulation in the electrophysiological study (EPS). Twenty-three out of 2000 patients with general diseases were involved. All patients with aborted sudden cardiac death, ventricular fibrillation or a family history of sudden cardiac death were excluded. The mean age was 72 ± 9 years, and 11 patients were male (47.8%). When the RR interval was shortened from 821 ± 142 ms to 464 ± 52 ms in the conducted APCs (P < 0.0001), J waves became diagnostic (0.02 ± 0.03 mV to 0.20 ± 0.07 mV, P < 0.0001). J waves were confined to the inferior leads in 22 (95.7%) patients and were notched in 11 (47.8%) and slurred in 12 (52.2%) patients. The induction of J waves was accompanied by visible changes of the QRS morphology. When the post-APC RR interval was prolonged to 992 ± 305 ms (P = 0.0154 vs. baseline), the J waves were similar to baseline levels. During the EPS, J wave induction was confirmed during atrial stimulation. There were no characteristic clinical or ECG features in the patients with tachycardia-induced J waves. J waves can be newly induced by short RR intervals in a general patient population, and a conduction delay is the likely mechanism causing such J waves. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For Permissions, please email: journals.permissions@oup.com.

Sports practice is related to parasympathetic activity in adolescents

PubMed Central

Cayres, Suziane Ungari; Vanderlei, Luiz Carlos Marques; Rodrigues, Aristides Machado; Coelho e Silva, Manuel João; Codogno, Jamile Sanches; Barbosa, Maurício Fregonesi; Fernandes, Rômulo Araújo

2015-01-01

OBJECTIVE: To analyze the relationship among sports practice, physical education class, habitual physical activity and cardiovascular risk in adolescents. METHODS: Cross-sectional study with 120 schoolchildren (mean: 11.7±0.7 years old), with no regular use of medicines. Sports practice and physical education classes were assessed through face-to-face interview, while habitual physical activity was assessed by pedometers. Bodyweight, height and height-cephalic trunk were used to estimate maturation. The following variables were measured: body fatness, blood pressure, resting heart rate, blood flow velocity, intima-media thickness (carotid and femoral) and heart rate variability (mean between consecutive heartbeats and statistical index in the time domain that show the autonomic parasympathetic nervous system activity root-mean by the square of differences between adjacent normal R-R intervals in a time interval). Statistical treatment used Spearman correlation adjusted by sex, ethnicity, age, body fatness and maturation. RESULTS: Independently of potential confounders, sports practice was positively related to autonomic parasympathetic nervous system activity (β=0.039 [0.01; 0.76]). On the other hand, the relationship between sport practice and mean between consecutive heartbeats (β=0,031 [-0.01; 0.07]) was significantly mediated by biological maturation. CONCLUSIONS: Sport practice was related to higher heart rate variability at rest. PMID:25887927

A Data-driven Study of RR Lyrae Near-IR Light Curves: Principal Component Analysis, Robust Fits, and Metallicity Estimates

NASA Astrophysics Data System (ADS)

Hajdu, Gergely; Dékány, István; Catelan, Márcio; Grebel, Eva K.; Jurcsik, Johanna

2018-04-01

RR Lyrae variables are widely used tracers of Galactic halo structure and kinematics, but they can also serve to constrain the distribution of the old stellar population in the Galactic bulge. With the aim of improving their near-infrared photometric characterization, we investigate their near-infrared light curves, as well as the empirical relationships between their light curve and metallicities using machine learning methods. We introduce a new, robust method for the estimation of the light-curve shapes, hence the average magnitudes of RR Lyrae variables in the K S band, by utilizing the first few principal components (PCs) as basis vectors, obtained from the PC analysis of a training set of light curves. Furthermore, we use the amplitudes of these PCs to predict the light-curve shape of each star in the J-band, allowing us to precisely determine their average magnitudes (hence colors), even in cases where only one J measurement is available. Finally, we demonstrate that the K S-band light-curve parameters of RR Lyrae variables, together with the period, allow the estimation of the metallicity of individual stars with an accuracy of ∼0.2–0.25 dex, providing valuable chemical information about old stellar populations bearing RR Lyrae variables. The methods presented here can be straightforwardly adopted for other classes of variable stars, bands, or for the estimation of other physical quantities.

Factor analytic reduction of the carotid-cardiac baroreflex parameters

NASA Technical Reports Server (NTRS)

Ludwig, David A.

1989-01-01

An accepted method for measuring the responsiveness of the carotid-cardiac baroreflex to arterial pressure changes is to artificially stimulate the baroreceptors in the neck. This is accomplished by using a pressurized neck cuff which constricts and distends the carotid artery and subsequently stimulates the baroreceptors. Nine physiological responses to this type of stimulation are quantified and used as indicators of the baroreflex. Thirty male humans between the ages 27 and 46 underwent the carotid-cardiac baroreflex test. The data for the nine response parameters were analyzed by principle component factor analysis. The results of this analysis indicated that 93 percent of the total variance across all nine parameters could be explained in four dimensions. Examination of the factor loadings following an orthogonal rotation of the principle components indicated four well defined dimensions. The first two dimensions reflected location points for R-R interval and carotid distending pressure respectively. The third dimension was composed of measures reflecting the gain of the reflex. The fourth dimension was the ratio of the resting R-R interval to R-R interval during simulated hypertension. The data suggests that the analysis of all nine baroreflex parameters is redundant.

Health effects of a thorium waste disposal site.

PubMed Central

Najem, G R; Voyce, L K

1990-01-01

A case-control study of 112 households residing in the vicinity of a thorium waste disposal site found a higher prevalence of birth defects (RR 2.1) and liver diseases (RR 2.3) among exposed than the unexposed group. The numbers were quite small and the confidence intervals wide, however, so that no definite conclusions can be drawn from these data. PMID:2316775

Impact of human immunodeficiency virus on the natural history of human papillomavirus genital infection in South African men and women.

PubMed

Mbulawa, Zizipho Z A; Marais, Dianne J; Johnson, Leigh F; Coetzee, David; Williamson, Anna-Lise

2012-07-01

This study investigated genital human papillomavirus (HPV) incidence and clearance in 278 human immunodeficiency virus (HIV)-seropositive (HIV-positive) women, 208 HIV-negative women, 161 HIV-positive men, and 325 HIV-negative men, followed at 6-month intervals for up to 24 months. HPV types were determined by the Roche Reverse Linear Array HPV genotyping assay. The rate of new HPV detection at the cervix and penis were 33.83 events/1000 person-months (95% confidence interval [CI], 26.39-43.46) and 55.68 events/1000 person-months (95% CI, 43.59-69.19), respectively. HIV infection was associated with increased risk of new HPV detection in women (relative risk [RR], 2.98; 95% CI, 2.07-4.29) and men (RR, 2.00; 95% CI, 1.49-2.69). The risk of new HPV detection increased in women (RR, 5.25; 95% CI, 3.52-7.81) and men (RR, 8.71; 95% CI, 6.19-12.24) when the sexual partner was infected with the same HPV type. The rate of clearing any HPV infection was 95.1 events/1000 person-months (95% CI, 83.3-108.1) in men and 66.9 events/1000 person-months (95% CI, 57.0-78.5) in women. HIV infection reduced the rate of HPV clearance in women (RR, 0.46; 95% CI, .34-.62) and men (RR, 0.71; 95% CI, .55-.93). HIV infection increases the risk of new HPV detection and decreases the rate of HPV clearance in both women and men.

Factors Associated With Shorter Colonoscopy Surveillance Intervals for Patients With Low-Risk Colorectal Adenomas and Effects on Outcome.

PubMed

Anderson, Joseph C; Baron, John A; Ahnen, Dennis J; Barry, Elizabeth L; Bostick, Roberd M; Burke, Carol A; Bresalier, Robert S; Church, Timothy R; Cole, Bernard F; Cruz-Correa, Marcia; Kim, Adam S; Mott, Leila A; Sandler, Robert S; Robertson, Douglas J

2017-06-01

Endoscopists do not routinely follow guidelines to survey individuals with low-risk adenomas (LRAs; 1-2 small tubular adenomas, < 1 cm) every 5-10 years for colorectal cancer; many recommend shorter surveillance intervals for these individuals. We aimed to identify the reasons that endoscopists recommend shorter surveillance intervals for some individuals with LRAs and determine whether timing affects outcomes at follow-up examinations. We collected data from 1560 individuals (45-75 years old) who participated in a prospective chemoprevention trial (of vitamin D and calcium) from 2004 through 2008. Participants in the trial had at least 1 adenoma, detected at their index colonoscopy, and were recommended to receive follow-up colonoscopy examinations at 3 or 5 years after adenoma identification, as recommended by the endoscopist. For this analysis we collected data from only participants with LRAs. These data included characteristics of participants and endoscopists and findings from index and follow-up colonoscopies. Primary endpoints were frequency of recommending shorter (3-year) vs longer (5-year) surveillance intervals, factors associated with these recommendations, and effect on outcome, determined at the follow-up colonoscopy. A 3-year surveillance interval was recommended for 594 of the subjects (38.1%). Factors most significantly associated with recommendation of 3-year vs a 5-year surveillance interval included African American race (relative risk [RR] to white, 1.41; 95% confidence interval [CI], 1.14-1.75), Asian/Pacific Islander ethnicity (RR to white, 1.7; 95% CI, 1.22-2.43), detection of 2 adenomas at the index examination (RR vs 1 adenoma, 1.47; 95% CI, 1.27-1.71), more than 3 serrated polyps at the index examination (RR=2.16, 95% CI, 1.59-2.93), or index examination with fair or poor quality bowel preparation (RR vs excellent quality, 2.16; 95% CI, 1.66-2.83). Other factors that had a significant association with recommendation for a 3-year surveillance interval included family history of colorectal cancer and detection of 1-2 serrated polyps at the index examination. In comparisons of outcomes, we found no significant differences between the 3-year vs 5-year recommendation groups in proportions of subjects found to have 1 or more adenomas (38.8% vs 41.7% respectively; P = .27), advanced adenomas (7.7% vs 8.2%; P = .73) or clinically significant serrated polyps (10.0% vs 10.3%; P = .82) at the follow-up colonoscopy. Possibly influenced by patients' family history, race, quality of bowel preparation, or number or size of polyps, endoscopists frequently recommend 3-year surveillance intervals instead of guideline-recommended intervals of 5 years or longer for individuals with LRAs. However, at the follow-up colonoscopy, similar proportions of participants have 1 or more adenomas, advanced adenomas, or serrated polyps. These findings support the current guideline recommendations of performing follow-up examinations of individuals with LRAs at least 5 years after the index colonoscopy. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

Randomized Item Response Theory Models

ERIC Educational Resources Information Center

Fox, Jean-Paul

2005-01-01

The randomized response (RR) technique is often used to obtain answers on sensitive questions. A new method is developed to measure latent variables using the RR technique because direct questioning leads to biased results. Within the RR technique is the probability of the true response modeled by an item response theory (IRT) model. The RR…

Effects of cold water immersion and active recovery on post-exercise heart rate variability.

PubMed

Bastos, F N; Vanderlei, L C M; Nakamura, F Y; Bertollo, M; Godoy, M F; Hoshi, R A; Junior, J N; Pastre, C M

2012-11-01

The aim of the present study was to investigate the potential benefits of cold water immersion (CWI) and active recovery (AR) on blood lactate concentration ([Lac]) and heart rate variability (HRV) indices following high-intensity exercise. 20 male subjects were recruited. On the first visit, an incremental test was performed to determine maximal oxygen consumption and the associated speed (MAS). The remaining 3 visits for the performance of constant velocity exhaustive tests at MAS and different recovery methods (6 min) were separated by 7-day intervals [randomized: CWI, AR or passive recovery (PR)]. The CWI and AR lowered [Lac] (p<0.05) at 11, 13 and 15 min after exercise cessation in comparison to PR. There was a 'time' and 'recovery mode' interaction for 2 HRV indices: standard deviation of normal R-R intervals (SDNN) (partial eta squared=0.114) and natural log of low-frequency power density (lnLF) (partial eta squared=0.090). CWI presented significantly higher SDNN compared to PR at 15 min of recovery (p<0.05). In addition, greater SDNN values were found in CWI vs. AR during the application of recovery interventions, and at 30 and 75 min post-exercise (p<0.05 for all differences). The lnLF during the recovery interventions and at 75 min post-exercise was greater using CWI compared with AR (p<0.05). For square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD) and natural log of high-frequency power density (lnHF), a moderate effect size was found between CWI and PR during the recovery interventions and at 15 min post-exercise. Our findings show that AR and CWI offer benefits regarding the removal of [Lac] following high-intensity exercise. While limited, CWI results in some improvement in post-exercise cardiac autonomic regulation compared to AR and PR. Further, AR is not recommended if the aim is to accelerate the parasympathetic reactivation. © Georg Thieme Verlag KG Stuttgart · New York.

[Risk of death 4 years after a 1st cerebral infarction: prospective study in Barquisimeto, Estado Lara, Venezuela].

PubMed

Poni, E; Granero, R; Escobar, B

1995-12-01

Stroke, the 5th. cause of death in Venezuela, has been associated to cerebral infarction. However, there is little information concerning lethality factors. 33 atherothrombotic subtype stroke patients, 31 (96%) Latino and 2(4%) white, were admitted into a prospective study to analyze the role of 11 mortality risk factors for those patients. A mortality relative risk (RR) > 1.5 or < 1 (protective) was considered clinically important if 1 was excluded from the 95% confidence interval (95%CI). The Mantel-Haenszel Chi-square procedure was use to test statistical significance (p < 0.05). Mortality RR for patients age 65 and over (RR = 2.95) and 4 year mortality RR for male patients (RR = 2.04) were clinically and statistically significant. History of high blood pressure was protective (RR = 0.62) probably due to good medical control. Cumulative mortality was higher than that of comparable studies, even from the first week of follow-up, reaching 67% at the 4th year.

Breastfeeding and the risk of childhood asthma: A two-stage instrumental variable analysis to address endogeneity.

PubMed

Sharma, Nivita D

2017-09-01

Several explanations for the inconsistent results on the effects of breastfeeding on childhood asthma have been suggested. The purpose of this study was to investigate one unexplored explanation, which is the presence of a potential endogenous relationship between breastfeeding and childhood asthma. Endogeneity exists when an explanatory variable is correlated with the error term for reasons such as selection bias, reverse causality, and unmeasured confounders. Unadjusted endogeneity will bias the effect of breastfeeding on childhood asthma. To investigate potential endogeneity, a cross-sectional study of breastfeeding practices and incidence of childhood asthma in 87 pediatric patients in Georgia, the USA, was conducted using generalized linear modeling and a two-stage instrumental variable analysis. First, the relationship between breastfeeding and childhood asthma was analyzed without considering endogeneity. Second, tests for presence of endogeneity were performed and having detected endogeneity between breastfeeding and childhood asthma, a two-stage instrumental variable analysis was performed. The first stage of this analysis estimated the duration of breastfeeding and the second-stage estimated the risk of childhood asthma. When endogeneity was not taken into account, duration of breastfeeding was found to significantly increase the risk of childhood asthma (relative risk ratio [RR]=2.020, 95% confidence interval [CI]: [1.143-3.570]). After adjusting for endogeneity, duration of breastfeeding significantly reduced the risk of childhood asthma (RR=0.003, 95% CI: [0.000-0.240]). The findings suggest that researchers should consider evaluating how the presence of endogeneity could affect the relationship between duration of breastfeeding and the risk of childhood asthma. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Physiology and pathophysiology of heart rate and blood pressure variability in humans: is power spectral analysis largely an index of baroreflex gain?

PubMed

Sleight, P; La Rovere, M T; Mortara, A; Pinna, G; Maestri, R; Leuzzi, S; Bianchini, B; Tavazzi, L; Bernardi, L

1995-01-01

1. It is often assumed that the power in the low- (around 0.10 Hz) and high-frequency (around 0.25 Hz) bands obtained by power spectral analysis of cardiovascular variables reflects sympathetic and vagal tone [corrected] respectively. An alternative model attributes the low-frequency band to a resonance in the control system that is produced by the inefficiently slow time constant of the reflex response to beat-to-beat changes in blood pressure effected by the sympathetic (with or without the parasympathetic) arm(s) of the baroreflex (De Boer model). 2. We have applied the De Boer model of circulatory variability to patients with varying baroreflex sensitivity to patients with varying baroreflex sensitivity and one normal subject, and have shown that the main differences in spectral power (for both low and high frequency) between and within subjects are caused by changes in the arterial baroreflex gain, particularly for vagal control of heart rate (R-R interval) and left ventricular stroke output. We have computed the power spectrum at rest and during neck suction (to stimulate carotid baroreceptors). We stimulated the baroreceptors at two frequencies (0.1 and 0.2 Hz), which were both distinct from the controlled respiration rate (0.25 Hz), in both normal subjects and heart failure patients with either sensitive or poor baroreflex control. 3. The data broadly confirm the De Boer model. The low-frequency (0.1 Hz) peak in either R-R or blood pressure variability) was spontaneously generated only if the baroreflex control of the autonomic outflow was relatively intact.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification and validation of asthma phenotypes in Chinese population using cluster analysis.

PubMed

Wang, Lei; Liang, Rui; Zhou, Ting; Zheng, Jing; Liang, Bing Miao; Zhang, Hong Ping; Luo, Feng Ming; Gibson, Peter G; Wang, Gang

2017-10-01

Asthma is a heterogeneous airway disease, so it is crucial to clearly identify clinical phenotypes to achieve better asthma management. To identify and prospectively validate asthma clusters in a Chinese population. Two hundred eighty-four patients were consecutively recruited and 18 sociodemographic and clinical variables were collected. Hierarchical cluster analysis was performed by the Ward method followed by k-means cluster analysis. Then, a prospective 12-month cohort study was used to validate the identified clusters. Five clusters were successfully identified. Clusters 1 (n = 71) and 3 (n = 81) were mild asthma phenotypes with slight airway obstruction and low exacerbation risk, but with a sex differential. Cluster 2 (n = 65) described an "allergic" phenotype, cluster 4 (n = 33) featured a "fixed airflow limitation" phenotype with smoking, and cluster 5 (n = 34) was a "low socioeconomic status" phenotype. Patients in clusters 2, 4, and 5 had distinctly lower socioeconomic status and more psychological symptoms. Cluster 2 had a significantly increased risk of exacerbations (risk ratio [RR] 1.13, 95% confidence interval [CI] 1.03-1.25), unplanned visits for asthma (RR 1.98, 95% CI 1.07-3.66), and emergency visits for asthma (RR 7.17, 95% CI 1.26-40.80). Cluster 4 had an increased risk of unplanned visits (RR 2.22, 95% CI 1.02-4.81), and cluster 5 had increased emergency visits (RR 12.72, 95% CI 1.95-69.78). Kaplan-Meier analysis confirmed that cluster grouping was predictive of time to the first asthma exacerbation, unplanned visit, emergency visit, and hospital admission (P < .0001 for all comparisons). We identified 3 clinical clusters as "allergic asthma," "fixed airflow limitation," and "low socioeconomic status" phenotypes that are at high risk of severe asthma exacerbations and that have management implications for clinical practice in developing countries. Copyright © 2017 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Factors Associated with Informed Decisions and Participation in Bowel Cancer Screening among Adults with Lower Education and Literacy.

PubMed

Smith, Sian K; Simpson, Judy M; Trevena, Lyndal J; McCaffery, Kirsten J

2014-08-01

Making informed decisions about cancer screening involves understanding the benefits and harms in conjunction with personal values. There is little research examining factors associated with informed decision making or participation in screening in the context of a decision aid trial. To identify factors associated with informed choice and participation in fecal occult blood testing (FOBT) among lower education populations. Randomized controlled trial of an FOBT decision aid conducted between July and November 2008. Socioeconomically disadvantaged areas in New South Wales, Australia. Included 572 adults aged 55 to 64 years with lower education. Sociodemographic variables, perceived health literacy, and involvement preferences in decision making were examined to identify predictors of informed choice (knowledge, attitudes, and behavior). Multivariate analysis identified independent predictors of making an informed choice as having higher education (relative risk [RR], 1.49; 95% confidence interval [CI], 1.13-1.95; P = 0.001), receiving the decision aid (RR, 2.88; 95% CI, 1.87-4.44; P < 0.001), and being male (RR, 1.48; 95% CI, 1.11-1.97; P = 0.009). Participants with no confidence in completing forms and poorer self-reported health were less likely to make an informed choice (RR, 0.74; 95% CI, 0.53-1.03; P = 0.05 and RR, 0.57; 95% CI, 0.36-0.89; P = 0.007, respectively). Independent predictors of completing the FOBT were positive screening attitudes, receiving the standard information, preference for making the decision alone, and knowing that screening may lead to false-positive/negative results. We did not objectively measure health literacy. Participants with the lowest levels of education had greater difficulties making an informed choice about participation in bowel screening. Alternative methods are needed to support informed decision making among lower education populations. © The Author(s) 2014.

A Perioperative Smoking Cessation Intervention With Varenicline, Counseling, and Fax Referral to a Telephone Quitline Versus a Brief Intervention: A Randomized Controlled Trial.

PubMed

Wong, Jean; Abrishami, Amir; Riazi, Sheila; Siddiqui, Naveed; You-Ten, Eric; Korman, Jennifer; Islam, Sazzadul; Chen, Xin; Andrawes, Maged S M; Selby, Peter; Wong, David T; Chung, Frances

2017-08-01

The effectiveness of perioperative interventions to quit smoking with varenicline has not been compared with brief interventions. Our objective was to determine the efficacy of a comprehensive smoking cessation program versus a brief intervention for smoking cessation. In this prospective, multicenter study, 296 patients were randomized to participate in a smoking cessation program (one 10- to 15-minute counseling session, pharmacotherapy with varenicline, an educational pamphlet, and a fax referral to a telephone quitline); or brief advice and self-referral to a telephone quitline. The primary outcome was the 7-day point prevalence (PP) abstinence at 12 months after surgery. Secondary outcomes included abstinence at 1, 3, and 6 months. Multivariable generalized linear regression was used to identify independent variables related to abstinence. The 7-day PP abstinence for the smoking cessation program versus brief advice group was 42.4% vs 26.2% (relative risk [RR], 1.62; 95% confidence interval [CI], 1.16-2.25; P = .003) at 12 months. The 7-day PP abstinence at 1, 3, and 6 months was higher in the smoking cessation group versus the brief advice group: 45.7% vs 25.5% (RR, 1.79; 95% CI, 1.29-2.49; P < .001), 46.4% vs 26.9% (RR, 1.72; 95% CI, 1.25-2.37; P< .001), and 45.0% vs 26.2% (RR, 1.72; 95% CI, 1.24-2.38; P < .001), respectively. Participating in the smoking cessation group predicted abstinence at 12 months (RR, 1.58; 95% CI, 1.12-2.21; P = .0087). A perioperative smoking cessation program with counseling, pharmacotherapy with varenicline, an educational pamphlet, and a fax referral to a quitline increased abstinence from smoking 1, 3, 6, and 12 months after surgery versus a brief intervention.

Assessing heat load in drylot dairy cattle: Refining on-farm sampling methodology.

PubMed

Tresoldi, Grazyne; Schütz, Karin E; Tucker, Cassandra B

2016-11-01

Identifying dairy cattle experiencing heat stress and adopting appropriate mitigation strategies can improve welfare and profitability. However, little is known about how cattle use heat abatement resources (shade, sprayed water) on drylot dairies. It is also unclear how often we need to observe animals to measure high heat load, or the relevance of specific aspects of this response, particularly in terms of panting. Our objectives were to describe and determine sampling intervals to measure cattle use of heat abatement resources, respiration rate (RR) and panting characteristics (drooling, open mouth, protruding tongue), and to evaluate the relationship between the latter 2. High-producing cows were chosen from 4 drylots (8 cows/dairy, n=32) and observed for at least 5.9h (1000 to 1800h, excluding milking) when air temperature, humidity, and the combined index averaged 33°C, 30%, and 79, respectively. Use of heat abatement resources was recorded continuously; RR and the presence and absence of each panting characteristic were recorded every 5min. From the observed values, estimates using the specified sub-sampling intervals were calculated for heat abatement resource use (1, 5, 10, 15, 20, 30, 60, 90, and 120min), and for RR and panting (10, 15, 20, 30, 60, 90, and 120min). Estimates and observed values were compared using linear regression. Sampling intervals were considered accurate if they met 3 criteria: R 2 ≥0.9, intercept=0, and slope=1. The relationship between RR and each panting characteristic was analyzed using mixed models. Cows used shade (at corral or over feed bunk) and feed bunk area (where water was sprayed) for about 90 and 50% of the observed time, respectively, and used areas with no cooling for 2min at a time, on average. Cows exhibited drooling (34±4% of observations) more often than open mouth and protruding tongue (11±3 and 8±3% of observations, respectively). Respiration rate varied depending on the presence of panting (with vs. without drool present: 97±3 vs. 74±3 breaths/min; open vs. closed mouth: 104±4 vs. 85±4 breaths/min; protruding vs. non-protruding tongue: 105±5 vs. 91±5 breaths/min). Accurate estimates were obtained when using sampling intervals ≤90min for RR, ≤60min for corral shade and sprayed water use, and ≤30min for drooling. In a hot and dry climate, cows kept in drylots had higher RR when showing panting characteristics than when these were absent, and used shade extensively, avoiding areas with no cooling. In general, 30min intervals were most efficient for measuring heat load responses. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Cardiac autonomic activity has a circadian rhythm in summer but not in winter in non-lactating pregnant dairy cows.

PubMed

Kovács, Levente; Kézér, Fruzsina Luca; Ruff, Ferenc; Szenci, Ottó

2016-03-01

This investigation was conducted to examine circadian and seasonal rhythms of heart rate and heart rate variability (HRV) by means of hour-by-hour recordings over 24h in a large population of non-lactating Holstein-Friesian pregnant cows [N=56, summer (June-July); N=61, winter (November-December)]. Data were collected during a 5-day period from each animal. Besides parameters of cardiac autonomic function [the high-frequency (HF) component of HRV and the ratio between the low-frequency (LF) and the HF components (LF/HF ratio)], the RR triangular index and Lmax were calculated. A clear circadian profile was observed for every parameter in summer. Heart rate elevated gradually with the course of the day from 7:00 to 17:00 o'clock and then slightly decreased from 18:00 to 6:00. Sympathovagal balance shifted towards sympathetic dominance during the daytime (increased LF/HF ratio), whereas parasympathetic activity was predominant during the night (increased HF). Lmax reflected a chaotic behavior of heart rate fluctuations during the afternoon in summer. Decreased values of RR triangular index indicated a sensitive period for cows between 14:00 and 16:00 o'clock in summer. During winter, except for the RR triangular (RRtri) index reflecting a high overall variability in R-R intervals between 12:00 and 23:00 o'clock, heart rate and HRV showed no periodicity over the 24-h period. The results suggest an impaired cardiac autonomic function during daytime in summer. HF, Lmax and RRtri index showed seasonal differences for both daytime and nighttime. Heart rate was higher in summer than in winter during the daytime, whereas the LF/HF ratio was higher in winter during the nighttime. Circadian and seasonal rhythms of cardiovascular function are presumably related to the differing temperature, and animal activity associated with summer and winter. As all of the investigated parameters are commonly used in bovine HRV research, these findings have practical implications for behavioral, physiological and welfare studies on dairy cattle. Copyright © 2015 Elsevier Inc. All rights reserved.

[The characteristics of RR-Lorenz plot in persistent atrial fibrillation patients complicating with escape beats and rhythm].

PubMed

Pan, Yunping; Zhang, Fangfang; Liu, Ru; Jing, Yan; Shen, Jihong; Li, Zhongjian; Zhu, Huaijie

2014-06-01

To explore the characteristics of RR-Lorenz plot in persistent atrial fibrillation (AF) patients complicating with escape beats and rhythm though ambulatory electrocardiogram. The 24-hour ambulatory electrocardiogram of 291 persistent AF patients in second affiliated hospital of Zhengzhou university from July 2005 to April 2013 were retrospectively analyzed and the RR interval and the QRS wave were measured. Patients were divided into two groups according to the distribution of the RR-Lorenz point [AF without escape beats and rhythm group (Group A, n = 259) and AF with escape beats and rhythm group (Group B, n = 32)]. The characteristics of RR-Lorenz plot between the two groups were compared. (1) Fan-shaped RR-Lorenz plots were evidenced in Group A. (2)In Group B, 30 cases showed fan-shaped with L-shaped and a short dense rods along 45° line. The proportion of escape beats and rhythm was 0.28% (275/98 369) -14.06% (11 263/80 112) . The other 2 cases in group B showed no typical RR-Lorenz plots features. RR-Lorenz plot could help to quickly diagnose persistent AF complicating with escape beats and rhythm according to the typical RR-Lorenz plot characteristics in 24-hour ambulatory electrocardiogram.

Amnioinfusion for third trimester preterm premature rupture of membranes.

PubMed

Hofmeyr, G Justus; Eke, Ahizechukwu C; Lawrie, Theresa A

2014-03-30

Preterm premature rupture of membranes (PPROM) is a leading cause of perinatal morbidity and mortality. Amnioinfusion aims to restore amniotic fluid volume by infusing a solution into the uterine cavity. The objective of this review was to assess the effects of amnioinfusion for PPROM on perinatal and maternal morbidity and mortality. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (2 December 2013). Randomised trials of amnioinfusion compared with no amnioinfusion in women with PPROM. Three review authors independently assessed trials for inclusion. Two review authors independently assessed trial quality and extracted data. Data were checked for accuracy. We included five trials, of moderate quality, but we only analysed data from four studies (with a total of 241 participants). One trial did not contribute any data to the review.Transcervical amnioinfusion improved fetal umbilical artery pH at delivery (mean difference 0.11; 95% confidence interval (CI) 0.08 to 0.14; one trial, 61 participants) and reduced persistent variable decelerations during labour (risk ratio (RR) 0.52; 95% CI 0.30 to 0.91; one trial, 86 participants).Transabdominal amnioinfusion was associated with a reduction in neonatal death (RR 0.30; 95% CI 0.14 to 0.66; two trials, 94 participants), neonatal sepsis (RR 0.26; 95% CI 0.11 to 0.61; one trial, 60 participants), pulmonary hypoplasia (RR 0.22; 95% CI 0.06 to 0.88; one trial, 34 participants) and puerperal sepsis (RR 0.20; 95% CI 0.05 to 0.84; one trial, 60 participants). Women in the amnioinfusion group were also less likely to deliver within seven days of membrane rupture (RR 0.18; 95% CI 0.05 to 0.70; one trial, 34 participants). These results should be treated with circumspection as the positive findings were mainly due to one trial with unclear allocation concealment. These results are encouraging but are limited by the sparse data and unclear methodological robustness, therefore further evidence is required before amnioinfusion for PPROM can be recommended for routine clinical practice.

Does an Obesity Paradox Really Exist After Cardiovascular Intervention?: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies.

PubMed

Bundhun, Pravesh Kumar; Li, Nuo; Chen, Meng-Hua

2015-11-01

Several studies have shown the existence of an obesity paradox after Percutaneous Coronary Intervention (PCI). However, other studies have shown its absence. This study sought to perform a systematic review and meta-analysis of studies comparing the mortality risk between high body mass index patients and normal weight patients after PCI.We have searched PubMed, Embase, and Chinese medical journal for randomized controlled trials (RCTs) and observational studies published between the year 2000 and 2015 by typing the keywords "percutaneous coronary intervention" and "obesity paradox." The main outcome was "all-cause mortality". RevMan 5.3 software was used to calculate the risk ratio (RR) with 95% confidence interval (CI) to express the pooled effect on discontinuous variables.Twenty-two studies have been included in this meta-analysis consisting of a total of 242,377 patients with 73,143 normal weight patients, 103,608 overweight, and 65,626 obese patients. Younger age, higher cardiovascular risk factors and the intensive use of medications have mainly been observed among obese patients followed by overweight and normal weight patients respectively. In-hospital, 12 months and ≥ 1 year (long-term) mortality risks were significantly lower in the overweight and obese groups with (RR: 0.67; 95% CI: 0.63-0.72, P < 0.00001) and (RR: 0.60; 95% CI: 0.56-0.65, P < 0.00001) respectively in the in-hospital follow-up (RR: 0.62; 95% CI: 0.55-0.71 and 0.57; 95% CI: 0.52-0.63, P < 0.00001) at 12 months, and (RR: 0.70; 95% CI: 0.64-0.76; P < 0.00001) and (RR: 0.80; 95% CI: 0.71-0.91, P = 0.0006) respectively for the long-term follow-up after PCI.This "obesity paradox" does exist after PCI. The mortality in overweight and obese patients is really significantly lower compared to the normal weight patients. However, the exact reasons for this phenomenon need further exploration and research in the future.

Patterns of ectopy leading to increased risk of fatal or near-fatal cardiac arrhythmia in patients with depressed left ventricular function after an acute myocardial infarction.

PubMed

Lerma, Claudia; Gorelick, Alexander; Ghanem, Raja N; Glass, Leon; Huikuri, Heikki V

2013-09-01

To identify potential new markers for assessing the risk of sudden arrhythmic events based on a method that captures features of premature ventricular complexes (PVCs) in relation to sinus RR intervals in Holter recordings (heartprint). Holter recordings obtained 6 weeks after acute myocardial infarction from 227 patients with reduced ventricular function (left ventricular ejection fraction ≤ 40%) were used to produce heartprints. Measured indices were: PVCs per hour, standard deviation of coupling interval (SDCI), and the number of occurrences of the most prevalent form of PVCs (SNIB). Predictive values, survival analysis, and Cox regression with adjustment for clinical variables were performed based on primary endpoint, defined as an electrocardiogram-documented fatal or near-fatal arrhythmic event, death from any cause, and cardiac death. High ectopy (PVCs per hour ≥10) was a predictor of all endpoints. Repeating forms of PVCs (SNIB ≥ 83) was a predictor of primary endpoint, hazard ratio = 3.5 (1.3-9.5), and all-cause death, hazard ratio = 2.8 (1.1-7.3), but not cardiac death. SDCI ≤ 80 ms was a predictor of all-cause death and cardiac death, but not of primary endpoint. High ectopy, prevalence of repeating forms of PVCs, and low coupling interval variability are potentially useful risk markers of fatal or near-fatal arrhythmias after myocardial infarction.

Meat consumption, heterocyclic amines and colorectal cancer risk: the Multiethnic Cohort Study.

PubMed

Ollberding, Nicholas J; Wilkens, Lynne R; Henderson, Brian E; Kolonel, Laurence N; Le Marchand, Loïc

2012-10-01

Greater consumption of red and processed meat has been associated with an increased risk of colorectal cancer in several recent meta-analyses. Heterocyclic amines (HCAs) have been hypothesized to underlie this association. In this prospective analysis conducted within the Multiethnic Cohort Study, we examined whether greater consumption of total, red or processed meat was associated with the risk of colorectal cancer among 165,717 participants who completed a detailed food frequency questionnaire at baseline. In addition, we examined whether greater estimated intake of HCAs was associated with the risk of colorectal cancer among 131,763 participants who completed a follow-up questionnaire that included a meat-cooking module. A total of 3,404 and 1,757 invasive colorectal cancers were identified from baseline to the end of follow-up and from the date of administration of the meat-cooking module to the end of follow-up, respectively. Proportional hazard models were used to estimate basic and multivariable-adjusted relative risks (RRs) and 95% confidence intervals for colorectal cancer associated with dietary exposures. In multivariable models, no association with the risk of colorectal cancer was detected for density-adjusted total meat (RR(Q5 vs. Q1) = 0.93 [0.83-1.05]), red meat (RR = 1.02 [0.91-1.16]) or processed meat intake (RR = 1.06 [0.94-1.19]) or for total (RR = 0.90 [0.76-1.05]) or specific HCA intake whether comparing quintiles of dietary exposure or using continuous variables. Although our results do not support a role for meat or for HCAs from meat in the etiology of colorectal cancer, we cannot rule out the possibility of a modest effect. Copyright © 2012 UICC.

Quantifying the Risk of Spinal Injury in Motor Vehicle Collisions According to Ambulatory Status: A Prospective Analytical Study.

PubMed

McCoy, Christopher Eric; Loza-Gomez, Angelica; Lee Puckett, James; Costantini, Samantha; Penalosa, Patrick; Anderson, Craig; Schultz, Carl

2017-02-01

The association between ambulation at the scene of a motor vehicle collision (MVC) and spinal injury has never been quantified. To evaluate the association between ambulation and spinal injury in patients involved in a MVC. Prospective analytical-observational cohort study. Inclusion: patients sustaining traumatic injury in a MVC. Exclusion: < 18 years old, pregnancy. spinal injury defined as injury to the cervical, thoracic, or lumbar spinal cord, bones, or ligaments. Secondary outcome: Injury resulting in neurological deficit, need for surgery, or death. A generalized linear model was used to evaluate the association between outcome and predictor variables. Risk ratios [RR] were reported with a point estimate and 95% confidence interval (CI). A two-tailed alpha of < 0.05 was the threshold for statistical significance. There were 704 patients analyzed. Nonambulatory patients were 2.29 times more likely to sustain a spinal injury, compared to ambulatory patients (RR 2.29, 95% CI 1.34-3.91). Patients ≥ 65 years of age were 3.27 times more likely to sustain a spinal injury (RR 3.27, 95% CI 1.66-6.45). Patients with a Glasgow Coma Scale score ≤ 8 were 4.93 times more likely to sustain a spinal injury (RR 4.93, 95% CI 1.86-13.10). In this prospective analytical-observational study evaluating the association between ambulatory status and spinal injury in patients involved in MVCs, we observed that those patients who were nonambulatory were more than two times as likely to have a spinal injury compared to those patients who were ambulatory at the scene. Copyright © 2016 Elsevier Inc. All rights reserved.

Does the association of prostate cancer with night-shift work differ according to rotating vs. fixed schedule? A systematic review and meta-analysis.

PubMed

Mancio, Jennifer; Leal, Cátia; Ferreira, Marta; Norton, Pedro; Lunet, Nuno

2018-04-27

Recent studies suggested that the relation between night-shift work and prostate cancer may differ between rotating and fixed schedules. We aimed to quantify the independent association between night-shift work and prostate cancer, for rotating and fixed schedules. We searched MEDLINE for studies assessing the association of night-shift work, by rotating or fixed schedules, with prostate cancer. We computed summary relative risk (RR) estimates with 95% confidence intervals (95% CI) using the inverse variance method and quantified heterogeneity using the I 2 statistic. Meta-regression analysis was used to compare the summary RR estimates for rotating and fixed schedules, while reducing heterogeneity. A total of nine studies assessed the effect of rotating and, in addition, four of them provided the effect of fixed night-shift work, in relation to daytime workers. Rotating night-shift work was associated with a significantly increased risk of prostate cancer (RR = 1.06, 95% CI of 1.01 to 1.12; I 2  = 50%), but not fixed night-shift work (RR of 1.01, 95% CI of 0.81 to 1.26; I 2  = 33%). In meta-regression model including study design, type of population, and control of confounding, the summary RR was 20% higher for rotating vs. fixed schedule, with heterogeneity fully explained by these variables. This is the first meta-analysis suggesting that an increased risk of prostate cancer may be restricted to workers with rotating night shifts. However, the association was weak and additional studies are needed to further clarify this relation before it can be translated into measures for risk reduction in occupational settings.

Effect of Statin Use on Acute Kidney Injury Risk Following Coronary Artery Bypass Grafting

PubMed Central

Layton, J. Bradley; Kshirsagar, Abhijit V.; Simpson, Ross J.; Pate, Virginia; Funk, Michele Jonsson; Sturmer, Til; Brookhart, M. Alan

2013-01-01

Acute kidney injury (AKI) is a serious complication of cardiovascular surgery. While some non-experimental studies suggest statin use may reduce post-surgical AKI, methodological differences in study designs leave uncertainty regarding the reality or magnitude of the effect. We estimated the effect of pre-operative statin initiation on post-coronary artery bypass graft (CABG) AKI using an epidemiologic approach more closely simulating a randomized controlled trial in a large CABG patient population. We utilized healthcare claims from large, employer-based and Medicare insurance databases for the years 2000 – 2010. To minimize healthy user bias, we identified patients undergoing non-emergency CABG who either newly initiated a statin within 20 days prior to surgery or were unexposed for 200+ days prior to CABG. AKI was identified within 15 days following CABG. We calculated multivariable adjusted risk ratios (RR) and 95% confidence intervals (CI) with Poisson regression. Analyses were repeated using propensity score methods adjusted for clinical and healthcare utilization variables. We identified 17,077 CABG patients. Post-CABG AKI developed in 3.4% of statin initiators and 6.2% of non-initiators. After adjustment, we observed a protective effect of statin initiation on AKI (RR = 0.78, 95% CI 0.63, 0.96). This effect differed by age: ≥65 years, RR=0.91 (95% CI: 0.68, 1.20); <65 years, RR=0.62 (95% CI: 0.45, 0.86), although AKI was more common in the older age group (7.7 vs. 4.0%). In conclusion, statin initiation immediately prior to CABG may modestly reduce the risk of post-operative AKI, particularly in younger CABG patients. PMID:23273532

Sleep Disruption at Home As an Independent Risk Factor for Postoperative Delirium.

PubMed

Todd, Oliver M; Gelrich, Lisa; MacLullich, Alasdair M; Driessen, Martin; Thomas, Christine; Kreisel, Stefan H

2017-05-01

To determine whether sleep disruption at home or in hospital is an independent risk factor for postoperative delirium in older adults undergoing elective surgery. Prospective cohort study. German teaching hospital. Individuals aged 65 and older undergoing elective arthroplasty (N = 101). Preoperative questionnaires were used to assess sleep disruption at home (Pittsburgh Sleep Quality Index). Actigraphy was used to objectively measure sleep disruption in the hospital before and after surgery. Delirium was assessed daily after surgery using the Confusion Assessment Method and, if there was uncertainty, validated according to International Classification of Diseases, Tenth Revision (ICD-10), criteria. Twenty-seven participants developed postoperative delirium. Those with sleep disruption at home were 3.26 times as likely to develop postoperative delirium as those without (95% confidence interval (CI) = 1.34-7.92, P = .009). Participants with sleep disruption in hospital were 1.21 times as likely to develop postoperative delirium as those without (95% CI = 1.03-1.41, P = .02). When adjusting for other variables, risk remained significant for sleep disruption at home (risk ratio (RR) = 3.90, 95% CI = 2.14-7.11, P < .001) but not in the hospital (RR = 1.19, 95% CI = 0.69-2.07). Jointly modeling sleep disruption at home and in the hospital, adjusted for covariates, resulted in significant contributions of both (home: RR = 3.10, 95% CI = 1.34-7.17, P = .008; hospital: RR = 1.38 95% CI = 1.13-1.68, P = .002). Older people with sleep disruption at home are at significantly higher risk of developing postoperative delirium than those without. Sleep disruption in the hospital may further heighten this risk. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

Treating Hepatitis C in a Ryan White-Funded HIV Clinic: Has the Treatment Uptake Improved in the Interferon-Free Directly Active Antiviral Era?

PubMed

Cope, Rebecca; Glowa, Thomas; Faulds, Samantha; McMahon, Deborah; Prasad, Ramakrishna

2016-02-01

Now that highly efficacious, interferon-free (IFN-free), direct acting antivirals (DAA) for the treatment of hepatitis C (HCV) have closed the gap between treatment and cure, identifying barriers that prevent initiation of treatment is more crucial than ever. This is a retrospective study utilizing Electronic Medical Records and Prior Authorization Records to identify HCV treatment gaps, including predictors for intention-to-treat and treatment initiation in the first 15 months of a Ryan White funded human immunodeficiency virus (HIV)/HCV co-infection clinic. This study included 128 adults ≥ 18 years old with HIV and chronic HCV infection who had visited the treatment center at least once since January 2013. Provider intent-to-treat was used to differentiate patients actively considered for treatment based on documentation kept by a multidisciplinary HCV team. Members of this group who had gone on to initiate treatment were identified. Baseline characteristics were compared. Rates of active treatment consideration and treatment initiation were 30% and 14%, respectively. HCV treatment-naïve individuals were less likely to be considered for treatment [risk ratio (RR) 1.58, 95% confidence interval (CI) 1.07-2.32] and initiate therapy (RR 2.33, 95% CI 0.97-5.60). Advanced liver disease had no significant association. Black race (RR 1.96, 95% CI 0.90-4.25) and Medicaid insurance holders (RR 1.90, 95% CI 0.95-3.82) tended to be less likely to initiate therapy. The availability of IFN-free DAA regimens has yet to increase HCV treatment uptake in our HIV/HCV co-infected population. Barriers to HCV treatment initiation have shifted from medical contraindications to socioeconomic variables.

Short-term effects of meteorological factors on children hand, foot and mouth disease in Guangzhou, China

NASA Astrophysics Data System (ADS)

Chen, Chun; Lin, Hualiang; Li, Xiaoquan; Lang, Lingling; Xiao, Xincai; Ding, Peng; He, Peng; Zhang, Ying; Wang, Ming; Liu, Qiyong

2014-09-01

Hand, foot and mouth disease (HFMD) is a contagious viral illness that commonly affects infants and children. The underlying risk factors have not yet been systematically examined. This study analyzed the short-term effects of meteorological factors on children HFMD in Guangzhou, China. Daily count of HFMD among children younger than 15 years and meteorological variables from 2009 to 2011 were collected to construct the time series. A generalized additive model was applied to estimate the effects of meteorological factors on HFMD occurrence, after adjusting for long-term trend, seasonal trend, day of week, and public holidays. A negative association between temperature and children HFMD occurrence was observed at lag days 1-3, with the relative risk (RR) for a 1 °C increase on lag day 2 being 0.983 (95 % confidence intervals (CI) 0.977 to 0.989); positive effect was found for temperature at lag days 5-9, with the highest effect at lag day 6 (RR = 1.014, 95 % CI 1.006 to 1.023). Higher humidity was associated with increased HFMD at lag days 3-10, with the highest effect at lag day 8 (RR = 1.009 for 1 % increase in relative humidity, 95 % CI 1.007 to 1.010). And we also observed significant positive effect for rainfall at lag days 4 and 8 (RR = 1.001, 95 % CI 1.000 to 1.002) for 1-mm increase. Subgroup analyses showed that the positive effects of temperature were more pronounced among younger children. This study suggests that meteorological factors might be important predictors of children HFMD occurrence in Guangzhou.

Cardiac autonomic and haemodynamic recovery after a single session of aerobic exercise with and without blood flow restriction in older adults.

PubMed

Ferreira, Marina Lívia Venturini; Sardeli, Amanda Veiga; Souza, Giovana Vergínia De; Bonganha, Valéria; Santos, Lucas Do Carmo; Castro, Alex; Cavaglieri, Cláudia Regina; Chacon-Mikahil, Mara Patrícia Traina

2017-12-01

This study investigated the autonomic and haemodynamic responses to different aerobic exercise loads, with and without blood flow restriction (BFR). In a crossover study, 21 older adults (8 males and 13 females) completed different aerobic exercise sessions: low load without BFR (LL) (40% VO 2 max ), low load with BFR (LL-BFR) (40% VO 2 max + 50% BFR) and high load without BFR (HL) (70% VO 2 max ). Heart rate variability and haemodynamic responses were recorded during rest and throughout 30 min of recovery. HL reduced R-R interval, the root mean square of successive difference of R-R intervals and high frequency during 30 min of recovery at a greater magnitude compared with LL and LL-BFR. Sympathetic-vagal balance increased the values for HL during 30 min of recovery at a greater magnitude when compared with LL and LL-BFR. Post-exercise haemodynamic showed reduced values of double product at 30 min of recovery compared to rest in LL-BFR, while HL showed higher values compared to rest, LL-BFR and LL. Reduced systolic blood pressure was observed for LL-BFR (30 min) compared to rest. Autonomic and haemodynamic responses indicate lower cardiovascular stress after LL-BFR compared to HL, being this method, besides the functional adaptations, a potential choice to attenuate the cardiovascular stress after exercise in older adults.

Sympathovagal response to orthostatism in overt and in subclinical hyperthyroidism.

PubMed

Goichot, B; Brandenberger, G; Vinzio, S; Perrin, A E; Geny, B; Schlienger, J L; Simon, C

2004-04-01

Heart rate variability (HRV) is a measure of the physiological variation of R-R intervals, reflecting the sympathovagal balance. In both overt and subclinical hyperthyroidism, a relative increase in sympathetic activity has been demonstrated, mainly due to a decrease in vagal activity. The modifications of HRV during orthostatism in normal subjects resemble those seen in hyperthyroidism. We have studied the response of 19 patients with overt hyperthyroidism and 12 with subclinical hyperthyroidism during orthostatism using HRV and compared the results to those of 32 healthy controls. In the three groups, the R-R intervals decreased in the same proportion after orthostatism. The low frequency power (LF)/[LF + high frequency power (HF)] ratio, which reflects the sympathetic tone, also increased in the same proportion in the three groups. However, the mechanisms of the modulation of the sympathovagal balance during orthostatism were different among the three groups. In controls, the relative increase of sympathetic tone after orthostatism was due principally to a decrease in vagal tone (reflected by decreased power in the HF band), while in overt hyperthyroidism, where the power in the HF band was already minimal in the lying position, there was a clear increase in the LF band power during orthostatism. The results were intermediate in the subclinical hyperthyroidism group, reflecting a continuum of effects of the thyroid hormone excess on the autonomic nervous system. Our study shows that despite an apparent normal cardiovascular adaptation to orthostatism in hyperthyroidism, the modulation of the autonomic nervous system is profoundly modified.

[Determination of the anaerobic threshold by the rate of ventilation and cardio interval variability].

PubMed

Seluianov, V N; Kalinin, E M; Pak, G D; Maevskaia, V I; Konrad, A H

2011-01-01

The aim of this work is to develop methods for determining the anaerobic threshold according to the rate of ventilation and cardio interval variability during the test with stepwise increases load on the cycle ergometer and treadmill. In the first phase developed the method for determining the anaerobic threshold for lung ventilation. 49 highly skilled skiers took part in the experiment. They performed a treadmill ski-walking test with sticks with gradually increasing slope from 0 to 25 degrees, the slope increased by one degree every minute. In the second phase we developed a method for determining the anaerobic threshold according dynamics ofcardio interval variability during the test. The study included 86 athletes of different sports specialties who performed pedaling on the cycle ergometer "Monarch" in advance. Initial output was 25 W, power increased by 25 W every 2 min. The pace was steady--75 rev/min. Measurement of pulmonary ventilation and oxygen and carbon dioxide content was performed using gas analyzer COSMED K4. Sampling of arterial blood was carried from the ear lobe or finger, blood lactate concentration was determined using an "Akusport" instrument. RR-intervals registration was performed using heart rate monitor Polar s810i. As a result, it was shown that the graphical method for determining the onset of anaerobic threshold ventilation (VAnP) coincides with the accumulation of blood lactate 3.8 +/- 0.1 mmol/l when testing on a treadmill and 4.1 +/- 0.6 mmol/1 on the cycle ergometer. The connection between the measure of oxygen consumption at VAnP and the dispersion of cardio intervals (SD1), derived regression equation: VO2AnT = 0.35 + 0.01SD1W + 0.0016SD1HR + + 0.106SD1(ms), l/min; (R = 0.98, error evaluation function 0.26 L/min, p < 0.001), where W (W)--Power, HR--heart rate (beats/min), SD1--cardio intervals dispersion (ms) at the moment of registration of cardio interval threshold.

Risk factors for suicide in the Israeli army between the years 1992-2012: A case-control study.

PubMed

Shelef, L; Tomer, G; Tatsa-Laur, L; Kedem, R; Bonne, O; Fruchter, E

2017-01-01

Young age, availability of weapons, and stressful life events, increase the risk of suicide. The aim of the present study was to assess additional risk factors for suicide in the Israeli army. We conducted a case-control study, to assess risk factors for suicide. The cases comprised soldiers who died by suicide during their military service (n=462; 0.039% of all soldiers in the cohort). The control group consisted of soldiers who did not commit suicide but were in active service during the investigated period (n=1,170,895; 99.96%). Predictor variables, including socio-demographic and psychiatric diagnoses, were considered. Using a Generalized Linear Model with a Binary Logistic dependent variable to predict suicide, while controlling the effect of intervening variables, we found the following variables enhanced the risk for committing suicide: male (RR=6.703; P<0.001), country of origin: Ethiopia (RR=4.555; P=0.014), low socioeconomic status (RR=1.448; P=0.016) and low adjustment difficulties (RR=2.324; P<0.001). In addition, we found that in males only, Cluster B Personality Disorder (RR=2.548; P=0.027), low (RR=1.657; P=0.002), to average motivation to serve in a combat unit (RR=1.322; P=0.046) increased the risk for suicide. IDF Soldiers bearing a psychiatric diagnosis or severe adjustment difficulties remained tightly monitored through their military service, and were found to be at a lower risk for suicide. However, those enlisted with mild (low) difficulties, were found to be at greater risk for suicide, as well as soldiers whose country of origin is Ethiopia. Suicide prevention program should focus on monitoring soldiers with these risk factors, together with soldiers' guidance regarding help seeking and de-stigmatizing suicide. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

The Carina Project. I. Bright Variable Stars

NASA Astrophysics Data System (ADS)

Dall'Ora, M.; Ripepi, V.; Caputo, F.; Castellani, V.; Bono, G.; Smith, H. A.; Brocato, E.; Buonanno, R.; Castellani, M.; Corsi, C. E.; Marconi, M.; Monelli, M.; Nonino, M.; Pulone, L.; Walker, A. R.

2003-07-01

We present new BV time series data of the Carina dwarf spheroidal galaxy (dSph). Current data cover an area of ~0.3 deg2 around the center of the galaxy and allow us to identify 92 variables. Among them 75 are RR Lyrae stars, 15 are bona fide anomalous Cepheids, one might be a Galactic field RR Lyrae star, and one is located along the Carina red giant branch. Expanding upon the seminal photographic investigation by Saha, Monet, & Seitzer we supply, for the first time, accurate estimates of their pulsation parameters (periods, amplitudes, mean magnitudes, and colors) on the basis of CCD photometry. Approximately 50% of both RR Lyrae stars and anomalous Cepheids are new identifications. Among the RR Lyrae sample, six objects are new candidate double-mode (RRd) variables. On the basis of their pulsation properties we estimate that two variables (V158, V182) are about 50% more massive than typical RR Lyrae stars, while the bulk of the anomalous Cepheids are roughly a factor of 2 more massive than fundamental-mode (RRab) RR Lyrae stars. This finding supports the evidence that these objects are intermediate-mass stars during central He-burning phases. We adopted three different approaches to estimate the Carina distance modulus, namely, the first-overtone blue edge method, the period-luminosity-amplitude relation, and the period-luminosity-color relation. We found DM=20.19+/-0.12, a result that agrees quite well with similar estimates based on different distance indicators. The data for Carina, together with data available in the literature, strongly support the conclusion that dSph's can barely be classified into the classical Oosterhoff dichotomy. The mean period of RRab's in Carina resembles that found for Oosterhoff type II clusters, whereas the ratio between first-overtone (RRc) pulsators and the total number of RR Lyrae stars is quite similar to that found in Oosterhoff type I clusters. Based on observations collected at the European Southern Observatory, La Silla, Chile, on Osservatorio Astronomico di Capodimonte guaranteed time.

Confidence Intervals for Proportion Estimates in Complex Samples. Research Report. ETS RR-06-21

ERIC Educational Resources Information Center

Oranje, Andreas

2006-01-01

Confidence intervals are an important tool to indicate uncertainty of estimates and to give an idea of probable values of an estimate if a different sample from the population was drawn or a different sample of measures was used. Standard symmetric confidence intervals for proportion estimates based on a normal approximation can yield bounds…

Risk factors for urinary tract infection in children with prenatal renal pelvic dilatation.

PubMed

Coelho, Graziela M; Bouzada, Maria Candida F; Lemos, Gilberto S; Pereira, Alamanda K; Lima, Bernado P; Oliveira, Eduardo A

2008-01-01

The aim of this study was to identify risk factors for urinary tract infection during followup of children with fetal renal pelvic dilatation. A total of 192 patients were diagnosed with isolated renal pelvic dilatation between 1999 and 2006 and were prospectively followed. After initial clinical and imaging evaluation ultrasound, clinical examination and laboratory reviews were scheduled at 6-month intervals. The event of interest was incidence of episodes of febrile urinary tract infection. A survival analysis was performed to identify variables significantly associated with the event. Cox model was applied to identify variables that were independently associated with urinary tract infection. A significant uropathy was diagnosed in 78 infants (41%). Median followup was 24 months. During followup urinary tract infection occurred in 27 (14%) of the 192 children. The incidence rate of urinary tract infection decreased from 7.2 episodes per 1,000 person-months in the first year of life to 1.4 after the third year. By survival analysis the cumulative incidence of urinary tract infection for the whole series was estimated at 8% at age 12 months, 13% at 24 months and 21% at 36 months. After adjustment 2 variables were independent predictors of urinary tract infection during followup-female gender (RR 1.4, 95% CI, 1.04 to 1.8, p = 0.02) and presence of uropathy (RR 4.6, 95% CI, 1.8 to 11.3, p = 0.001). According to our findings, in a cohort of prenatal hydronephrosis girls with vesicoureteral reflux or urinary tract obstruction had a higher risk of urinary tract infection during followup.

Tramadol does not enhance sedation induced by acepromazine in dogs

PubMed Central

Monteiro, Eduardo R.; Lobo, Renan B.; Nunes, Juarez S.; Rangel, Julia P.P.; Bitti, Flavia S.

2016-01-01

The sedative effect of acepromazine combined with 2 doses of tramadol [3 and 5 mg/kg body weight (BW)] was compared with the sedative effect of acepromazine alone in dogs and the effects of each sedative protocol on cardiorespiratory variables were examined. This was a prospective, randomized, blinded, crossover study. Each of 6 dogs received 3 treatments at 1-week intervals. During all anesthetic episodes, dogs received 0.05 mg/kg BW acepromazine. Approximately 25 min later, dogs were given physiological saline (control) or tramadol [3 mg/kg BW (TR3) or 5 mg/kg BW (TR5)]. All drugs were administered intravenously. Variables evaluated included heart rate (HR), respiratory rate (RR), systolic, mean, and diastolic blood pressures (SAP, MAP, and DAP), and sedation [by use of a simple descriptive scale (SDS, range: 0 to 3) and a numeric rating scale (NRS, range: 0 to 10)]. Variables were recorded 25 min after acepromazine and for 80 min after saline or tramadol. Acepromazine administration resulted in mild sedation in most dogs and decreased RR, SAP, MAP, and DAP in all treatments. Tramadol administration did not significantly increase SDS or NRS scores compared to acepromazine alone. The only exception to this rule was observed at 20 min after TR3, when NRS was higher in this group than in the control treatment. Administration of tramadol (TR3 and TR5) decreased HR. Under the conditions of this study, sedation induced by acepromazine with tramadol was similar to that of acepromazine alone. The main adverse effects of the combination were a decrease in blood pressure and HR, without clinical significance. PMID:27733788

Heart rate variability indexes as a marker of chronic adaptation in athletes: a systematic review.

PubMed

da Silva, Vanessa Pereira; de Oliveira, Natacha Alves; Silveira, Heitor; Mello, Roger Gomes Tavares; Deslandes, Andrea Camaz

2015-03-01

Regular exercise promotes functional and structural changes in the central and peripheral mechanisms of the cardiovascular system. Heart rate variability (HRV) measurement provides a sensitive indicator of the autonomic balance. However, because of the diversity of methods and variables used, the results are difficult to compare in the sports sciences. Since the protocol (supine, sitting, or standing position) and measure (time or frequency domain) are not well defined, the aim of this study is to investigate the HRV measures that better indicates the chronic adaptations of physical exercise in athletes. PubMed (MEDLINE), Web of Science, SciELO (Scientific Electronic Library), and Scopus databases were consulted. Original complete articles in English with short-term signals evaluating young and adult athletes, between 17 and 40 years old, with a control group, published up to 2013 were included. Selected 19 of 1369 studies, for a total sample pool of 333 male and female athletes who practice different sports. The main protocols observed were the supine or standing positions in free or controlled breathing conditions. The main statistical results found in this study were the higher mean RR, standard deviation of RR intervals, and high frequency in athletes group. In addition, the analyses of Cohen's effect size showed that factors as modality of sport, protocol used and unit of measure selected could influence this expected results. Our findings indicate that time domain measures are more consistent than frequency domain to describe the chronic cardiovascular autonomic adaptations in athletes. © 2014 Wiley Periodicals, Inc.

Heart rate variability to monitor performance in elite athletes: Criticalities and avoidable pitfalls.

PubMed

Lucini, Daniela; Marchetti, Ilaria; Spataro, Antonio; Malacarne, Mara; Benzi, Manuela; Tamorri, Stefano; Sala, Roberto; Pagani, Massimo

2017-08-01

Spectral analysis of Heart Rate Variability (HRV) is a simple, non-invasive technique that is widely used in sport to assess sympatho-vagal regulation of the heart. Its employment is increasing partly due to the rising usage of wearable devices. However data acquisition using these devices may be suboptimal because they cannot discriminate between sinus and non-sinus beats and do not record any data regarding respiratory frequency. This information is mandatory for a correct clinical interpretation. This study involved 974 elite athletes, all of them underwent a complete autonomic assessment, by way of Autoregressive HRV analysis. In 91 subjects (9% of the total population) we observed criticalities of either cardiac rhythm or respiration. Through perusal of one-lead ECG analysis we observed that 77 subjects had atrial or ventricular ectopy, i.e. conditions which impair stationarity and sinus rhythm. Running anyway autonomic nervous system analysis in this population, we observed that RR variance and raw values of LF and HF regions are significantly higher in arrhythmic subjects. In addition 14 subjects had slow (about 6 breath/min, 0.1Hz) respiration. This condition clouds the separation between LF from HF spectral regions of RR interval variability, respectively markers of the prevalent sympathetic and vagal modulation of SA node and of their synergistic interaction. Caution must be payed when assessing HRV with non-ECG wearable devices. Recording ECG signal and ensuring that respiratory rate is higher than 10 breath/min are both prerequisites for a more reliable analysis of HRV particularly in athletes. Copyright © 2017 Elsevier B.V. All rights reserved.

Tramadol does not enhance sedation induced by acepromazine in dogs.

PubMed

Monteiro, Eduardo R; Lobo, Renan B; Nunes, Juarez S; Rangel, Julia P P; Bitti, Flavia S

2016-10-01

The sedative effect of acepromazine combined with 2 doses of tramadol [3 and 5 mg/kg body weight (BW)] was compared with the sedative effect of acepromazine alone in dogs and the effects of each sedative protocol on cardiorespiratory variables were examined. This was a prospective, randomized, blinded, crossover study. Each of 6 dogs received 3 treatments at 1-week intervals. During all anesthetic episodes, dogs received 0.05 mg/kg BW acepromazine. Approximately 25 min later, dogs were given physiological saline (control) or tramadol [3 mg/kg BW (TR3) or 5 mg/kg BW (TR5)]. All drugs were administered intravenously. Variables evaluated included heart rate (HR), respiratory rate (RR), systolic, mean, and diastolic blood pressures (SAP, MAP, and DAP), and sedation [by use of a simple descriptive scale (SDS, range: 0 to 3) and a numeric rating scale (NRS, range: 0 to 10)]. Variables were recorded 25 min after acepromazine and for 80 min after saline or tramadol. Acepromazine administration resulted in mild sedation in most dogs and decreased RR, SAP, MAP, and DAP in all treatments. Tramadol administration did not significantly increase SDS or NRS scores compared to acepromazine alone. The only exception to this rule was observed at 20 min after TR3, when NRS was higher in this group than in the control treatment. Administration of tramadol (TR3 and TR5) decreased HR. Under the conditions of this study, sedation induced by acepromazine with tramadol was similar to that of acepromazine alone. The main adverse effects of the combination were a decrease in blood pressure and HR, without clinical significance.

VizieR Online Data Catalog: OGLE RR Lyrae in LMC (Soszynski+, 2003)

NASA Astrophysics Data System (ADS)

Soszynski, I.; Udalski, A.; Szymanski, M.; Kubiak, M.; Pietrzynski, G.; Wozniak, P.; Zebrun, K.; Szewczyk, O.; Wyrzykowski, L.

2003-11-01

We present the catalog of RR Lyr stars discovered in a 4.5 square degrees area in the central parts of the Large Magellanic Cloud (LMC). Presented sample contains 7612 objects, including 5455 fundamental mode pulsators (RRab), 1655 first-overtone (RRc), 272 second-overtone (RRe) and 230 double-mode RR Lyr stars (RRd). Additionally we attach alist of several dozen other short-period pulsating variables. The catalog data include astrometry, periods, BVI photometry, amplitudes, and parameters of the Fourier decomposition of the I-band light curve of each object. We provide a list of six LMC star clusters which contain RR Lyr stars. The richest cluster, NGC 1835, hosts 84 RR Lyr variables. The period distribution of these stars suggests that NGC1835 shares features of Oosterhoff type I and type II groups. All presented data, including individual BVI observations and finding charts are available from the OGLE Internet archive at ftp://sirius.astrouw.edu.pl/ogle/ogle2/var_stars/lmc/rrlyr (6 data files).

The Catalina Surveys Southern periodic variable star catalogue

NASA Astrophysics Data System (ADS)

Drake, A. J.; Djorgovski, S. G.; Catelan, M.; Graham, M. J.; Mahabal, A. A.; Larson, S.; Christensen, E.; Torrealba, G.; Beshore, E.; McNaught, R. H.; Garradd, G.; Belokurov, V.; Koposov, S. E.

2017-08-01

Here, we present the results from our analysis of 6 yr of optical photometry taken by the Siding Spring Survey (SSS). This completes a search for periodic variable stars within the 30 000 deg2 of the sky covered by the Catalina Surveys. The current analysis covers 81 million sources with declinations between -20° and -75° with median magnitudes in the range 11 < V < 19.5. We find approximately 34 000 new periodic variable stars in addition to the ˜9000 RR Lyrae that we previously discovered in SSS data. This brings the total number of periodic variables identified in Catalina data to ˜110 000. The new SSS periodic variable stars mainly consist of eclipsing binaries, RR Lyrae, LPVs, RS CVn stars, δ Scutis, and Anomalous Cepheids. By cross-matching these variable stars with those from prior surveys, we find that ˜90 per cent of the sources are new discoveries and recover ˜95 per cent of the known periodic variables in the survey region. For the known sources, we find excellent agreement between our catalogue and prior values of luminosity, period, and amplitude. However, we find many variable stars that had previously been misclassified. Examining the distribution of RR Lyrae, we find a population associated with the Large Magellanic Cloud (LMC) that extends more than 20° from its centre confirming recent evidence for the existence of a very extended stellar halo in the LMC. By combining SSS photometry with Dark Energy Survey data, we identify additional LMC halo RR Lyrae, thus confirming the significance of the population.

Noninvasive method to estimate anaerobic threshold in individuals with type 2 diabetes.

PubMed

Sales, Marcelo M; Campbell, Carmen Sílvia G; Morais, Pâmella K; Ernesto, Carlos; Soares-Caldeira, Lúcio F; Russo, Paulo; Motta, Daisy F; Moreira, Sérgio R; Nakamura, Fábio Y; Simões, Herbert G

2011-01-12

While several studies have identified the anaerobic threshold (AT) through the responses of blood lactate, ventilation and blood glucose others have suggested the response of the heart rate variability (HRV) as a method to identify the AT in young healthy individuals. However, the validity of HRV in estimating the lactate threshold (LT) and ventilatory threshold (VT) for individuals with type 2 diabetes (T2D) has not been investigated yet. To analyze the possibility of identifying the heart rate variability threshold (HRVT) by considering the responses of parasympathetic indicators during incremental exercise test in type 2 diabetics subjects (T2D) and non diabetics individuals (ND). Nine T2D (55.6 ± 5.7 years, 83.4 ± 26.6 kg, 30.9 ± 5.2 kg.m2(-1)) and ten ND (50.8 ± 5.1 years, 76.2 ± 14.3 kg, 26.5 ± 3.8 kg.m2(-1)) underwent to an incremental exercise test (IT) on a cycle ergometer. Heart rate (HR), rate of perceived exertion (RPE), blood lactate and expired gas concentrations were measured at the end of each stage. HRVT was identified through the responses of root mean square successive difference between adjacent R-R intervals (RMSSD) and standard deviation of instantaneous beat-to-beat R-R interval variability (SD1) by considering the last 60 s of each incremental stage, and were known as HRVT by RMSSD and SD1 (HRVT-RMSSD and HRVT-SD1), respectively. No differences were observed within groups for the exercise intensities corresponding to LT, VT, HRVT-RMSSD and HHVT-SD1. Furthermore, a strong relationship were verified among the studied parameters both for T2D (r = 0.68 to 0.87) and ND (r = 0.91 to 0.98) and the Bland & Altman technique confirmed the agreement among them. The HRVT identification by the proposed autonomic indicators (SD1 and RMSSD) were demonstrated to be valid to estimate the LT and VT for both T2D and ND.

Cardiac autonomic dysfunction is associated with high-risk albumin-to-creatinine ratio in young adolescents with type 1 diabetes in AdDIT (adolescent type 1 diabetes cardio-renal interventional trial).

PubMed

Cho, Yoon Hi; Craig, Maria E; Davis, Elizabeth A; Cotterill, Andrew M; Couper, Jennifer J; Cameron, Fergus J; Benitez-Aguirre, Paul Z; Dalton, R Neil; Dunger, David B; Jones, Timothy W; Donaghue, Kim C

2015-04-01

This study examined the association between cardiac autonomic dysfunction and high albumin-to-creatinine ratio (ACR) in adolescents with type 1 diabetes. Adolescents recruited as part of a multicenter screening study (n = 445, 49% female, aged 10-17 years, mean duration 6.9 years; mean HbA1c 8.4%, 68 mmol/mol) underwent a 10-min continuous electrocardiogram recording for heart rate variability analysis. Time-domain heart rate variability measures included baseline heart rate, SD of the R-R interval (SDNN), and root mean squared difference of successive R-R intervals (RMSSD). Spectral analysis included sympathetic (low-frequency) and parasympathetic (high-frequency) components. Standardized ACR were calculated from six early morning urine collections using an established algorithm, reflecting age, sex, and duration, and stratified into ACR tertiles, where the upper tertile reflects higher nephropathy risk. The upper-tertile ACR group had a faster heart rate (76 vs. 73 bpm; P < 0.01) and less heart rate variability (SDNN 68 vs. 76 ms, P = 0.02; RMSSD 63 vs. 71 ms, P = 0.04). HbA1c was 8.5% (69 mmol/mmol) in the upper tertile vs. 8.3% (67 mmol/mol) in the lower tertiles (P = 0.07). In multivariable analysis, upper-tertile ACR was associated with faster heart rate (β = 2.5, 95% CI 0.2-4.8, P = 0.03) and lower RMSSD (β = -9.5, 95% CI -18.2 to -0.8, P = 0.03), independent of age and HbA1c. Adolescents at potentially higher risk for nephropathy show an adverse cardiac autonomic profile, indicating sympathetic overdrive, compared with the lower-risk group. Longitudinal follow-up of this cohort will further characterize the relationship between autonomic and renal dysfunction and the effect of interventions in this population. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Heart Rate Dynamics and their Relation with the Cyclic Alternating Pattern of Sleep in Normal Subjects and NFLE Patients

NASA Astrophysics Data System (ADS)

González, Jose S.; Dorantes, Guadalupe; Alba, Alfonso; Méndez, Martin O.; Camacho, Sergio; Luna-Rivera, Martin; Parrino, Liborio; Riccardi, Silvia; Terzano, Mario G.; Milioli, Giulia

The aim of this work is to study the behavior of the autonomic system through variations in the heart rate (HR) during the Cyclic Alternating Pattern (CAP) which is formed by A-phases. The analysis was carried out in 10 healthy subjects and 10 patients with Nocturnal Front Lobe Epilepsy (NFLE) that underwent one whole night of polysomnographic recordings. In order to assess the relation of A-phases with the cardiovascular system, two time domain features were computed: the amplitude reduction and time delay of the minimum of the R-R intervals with respect to A-phases onset. In addition, the same process was performed over randomly chosen R-R interval segments during the NREM sleep for baseline comparisons. A non-parametric bootstrap procedure was used to test differences of the kurtosis values of two populations. The results suggest that the onset of the A-phases is correlated with a significant increase of the HR that peaks at around 4s after the A-phase onset, independently of the A-phase subtype and sleep time for both healthy subjects and NFLE patients. Furthermore, the behavior of the reduction in the R-R intervals during the A-phases was significantly different for NFLE patients with respect to control subjects.

Respiratory modulation of human autonomic rhythms

NASA Technical Reports Server (NTRS)

Badra, L. J.; Cooke, W. H.; Hoag, J. B.; Crossman, A. A.; Kuusela, T. A.; Tahvanainen, K. U.; Eckberg, D. L.

2001-01-01

We studied the influence of three types of breathing [spontaneous, frequency controlled (0.25 Hz), and hyperventilation with 100% oxygen] and apnea on R-R interval, photoplethysmographic arterial pressure, and muscle sympathetic rhythms in nine healthy young adults. We integrated fast Fourier transform power spectra over low (0.05-0.15 Hz) and respiratory (0.15-0.3 Hz) frequencies; estimated vagal baroreceptor-cardiac reflex gain at low frequencies with cross-spectral techniques; and used partial coherence analysis to remove the influence of breathing from the R-R interval, systolic pressure, and muscle sympathetic nerve spectra. Coherence among signals varied as functions of both frequency and time. Partialization abolished the coherence among these signals at respiratory but not at low frequencies. The mode of breathing did not influence low-frequency oscillations, and they persisted during apnea. Our study documents the independence of low-frequency rhythms from respiratory activity and suggests that the close correlations that may exist among arterial pressures, R-R intervals, and muscle sympathetic nerve activity at respiratory frequencies result from the influence of respiration on these measures rather than from arterial baroreflex physiology. Most importantly, our results indicate that correlations among autonomic and hemodynamic rhythms vary over time and frequency, and, thus, are facultative rather than fixed.

Peripheral neuromuscular dysfunction and falls in an elderly cohort.

PubMed

Sorock, G S; Labiner, D M

1992-09-01

In a prospective study of 169 tenants of senior citizen housing in New Jersey in 1986-1987, the relations between tests of peripheral sensory and motor functions in the lower extremities and the rate of first falls were evaluated. The mean age of the cohort was 79.8 years. Fifty-seven persons fell at least once during the follow-up period (mean, 5.6 months). After adjustment for history of stroke, heart failure, emphysema, and use of a walker or cane, rate ratios for first falls were elevated in subjects with reduced toe joint position sense (rate ratio (RR) = 2.2) and sharp-dull discrimination (RR = 2.0), but to a lesser extent for reduced ankle strength (RR = 1.5). Presence of one or more of these three deficits was defined as a peripheral neuromuscular dysfunction and was associated with first falls after adjustment for multiple covariates (RR = 2.4, 95% confidence interval 1.3-4.5). Having two or all three sensory or motor deficits increased the rate of falling 3.9 times (95% confidence interval 2.1-7.0) compared with persons without these deficits. These data suggest that impaired sensory and motor function of the lower extremities plays an important role in falls in the elderly.

Effects of immigrant status on Emergency Room (ER) utilisation by children under age one: a population-based study in the province of Reggio Emilia (Italy)

PubMed Central

2013-01-01

Background The primary aim of this study was to assess the effect of immigrant status on Emergency Room (ER) utilisation by children under age one, considering all, non-urgent, very urgent, and followed by hospitalisation visits. The second aim was to investigate the role played by mother’s educational level in the relationship between citizenship and ER utilisation. Methods The cohort study included all healthy singleton live births in the years 2008–2009 and residing in the province of Reggio Emilia, followed for the first year of life in order to study their ER visits. The outcomes were the ER utilisation rate for all, non-urgent, very urgent, and followed by hospitalisation visits. The main explanatory variable was mother’s citizenship. Other covariates were mother’s educational level, maternal age, parity, and child gender. Multivariate analyses (negative binomial regression and zero inflated when appropriate) were performed. Adjusted utilisation Rate Ratios (RR) and their 95% Confidence Intervals (95% CI) were calculated. Trend for age in months by citizenship is depicted. Results There were 3,191 children (36.4%) with at least one ER visit in the first year of life. Adjusted RR show a significantly greater risk of ER visit for immigrants than for Italians: (RR 1.51; 95% CI 1.39-1.63). Immigrants also had a higher risk of non-urgent visits (RR 1.72; 95% CI 1.48-2.00) and for visits followed by hospitalizations (RR 1.58; 95% CI 1.33-1.89). For very urgent visits, the immigrants had a slightly higher risk compared to Italians (RR 1.25; 95% CI 0.98-1.59). The risk of ER visits is higher in the first two months of life (RR1stvs 3rd-12th 2.08; 95% CI 1.93-2.24 and RR 2ndvs 3rd-12th 1.45; 95% CI 1.33-1.58, respectively). Considering all visits, the ER utilisation rate was inversely related with maternal education only for Italians (low educational level 44.0 and high educational level 73.9 for 100 children; p value for trend test < 0.001). Conclusions Our study observed a higher use of ER services by immigrant children and, to a lesser extent, by children of less educated Italian mothers. In immigrants, the excess is mostly due to non-urgent visits and only slightly to high acute conditions. PMID:24176109

Cardiovascular autonomic modulation and activity of carotid baroreceptors at altitude.

PubMed

Bernardi, L; Passino, C; Spadacini, G; Calciati, A; Robergs, R; Greene, R; Martignoni, E; Anand, I; Appenzeller, O

1998-11-01

1. To assess the effects of acute exposure to high altitude on baroreceptor function in man we evaluated the effects of baroreceptor activation on R-R interval and blood pressure control at high altitude. We measured the low-frequency (LF) and high-frequency (HF) components in R-R, non-invasive blood pressure and skin blood flow, and the effect of baroreceptor modulation by 0. 1-Hz sinusoidal neck suction. Ten healthy sea-level natives and three high-altitude native, long-term sea-level residents were evaluated at sea level, upon arrival at 4970 m and 1 week later.2. Compared with sea level, acute high altitude decreased R-R and increased blood pressure in all subjects [sea-level natives: R-R from 1002+/-45 to 775+/-57 ms, systolic blood pressure from 130+/-3 to 150+/-8 mmHg; high-altitude natives: R-R from 809+/-116 to 749+/-47 ms, systolic blood pressure from 110+/-12 to 125+/-11 mmHg (P<0.05 for all)]. One week later systolic blood pressure was similar to values at sea level in all subjects, whereas R-R remained elevated in sea-level natives. The low-frequency power in R-R and systolic blood pressure increased in sea-level natives [R-R-LF from 47+/-8 to 65+/-10% (P<0.05), systolic blood pressure-LF from 1.7+/-0. 3 to 2.6+/-0.4 ln-mmHg2 (P<0.05)], but not in high-altitude natives (R-R-LF from 32+/-13 to 38+/-19%, systolic blood pressure-LF from 1. 9+/-0.5 to 1.7+/-0.8 ln-mmHg2). The R-R-HF decreased in sea-level natives but not in high-altitude natives, and no changes occurred in systolic blood pressure-HF. These changes remained evident 1 week later. Skin blood flow variability and its spectral components decreased markedly at high altitude in sea-level natives but showed no changes in high-altitude natives. Neck suction significantly increased the R-R- and systolic blood pressure-LF in all subjects at both sea level and high altitude.3. High altitude induces sympathetic activation in sea-level natives which is partially counteracted by active baroreflex. Despite long-term acclimatization at sea level, high-altitude natives also maintain active baroreflex at high altitude but with lower sympathetic activation, indicating a persisting high-altitude adaptation which may be genetic or due to baroreflex activity not completely lost by at least 1 year's sea-level residence.

Effects of immigrant status on Emergency Room (ER) utilisation by children under age one: a population-based study in the province of Reggio Emilia (Italy).

PubMed

Ballotari, Paola; D'Angelo, Stefania; Bonvicini, Laura; Broccoli, Serena; Caranci, Nicola; Candela, Silvia; Giorgi Rossi, Paolo

2013-11-01

The primary aim of this study was to assess the effect of immigrant status on Emergency Room (ER) utilisation by children under age one, considering all, non-urgent, very urgent, and followed by hospitalisation visits. The second aim was to investigate the role played by mother's educational level in the relationship between citizenship and ER utilisation. The cohort study included all healthy singleton live births in the years 2008-2009 and residing in the province of Reggio Emilia, followed for the first year of life in order to study their ER visits. The outcomes were the ER utilisation rate for all, non-urgent, very urgent, and followed by hospitalisation visits. The main explanatory variable was mother's citizenship. Other covariates were mother's educational level, maternal age, parity, and child gender. Multivariate analyses (negative binomial regression and zero inflated when appropriate) were performed. Adjusted utilisation Rate Ratios (RR) and their 95% Confidence Intervals (95% CI) were calculated. Trend for age in months by citizenship is depicted. There were 3,191 children (36.4%) with at least one ER visit in the first year of life. Adjusted RR show a significantly greater risk of ER visit for immigrants than for Italians: (RR 1.51; 95% CI 1.39-1.63). Immigrants also had a higher risk of non-urgent visits (RR 1.72; 95% CI 1.48-2.00) and for visits followed by hospitalizations (RR 1.58; 95% CI 1.33-1.89). For very urgent visits, the immigrants had a slightly higher risk compared to Italians (RR 1.25; 95% CI 0.98-1.59).The risk of ER visits is higher in the first two months of life (RR(1st vs 3rd-12th) 2.08; 95% CI 1.93-2.24 and RR(2nd vs 3rd-12th) 1.45; 95% CI 1.33-1.58, respectively). Considering all visits, the ER utilisation rate was inversely related with maternal education only for Italians (low educational level 44.0 and high educational level 73.9 for 100 children; p value for trend test < 0.001). Our study observed a higher use of ER services by immigrant children and, to a lesser extent, by children of less educated Italian mothers. In immigrants, the excess is mostly due to non-urgent visits and only slightly to high acute conditions.

Muscle metaboreflex contribution to cardiovascular regulation during dynamic exercise in microgravity: insights from mission STS-107 of the space shuttle Columbia.

PubMed

Iellamo, Ferdinando; Di Rienzo, Marco; Lucini, Daniela; Legramante, Jacopo M; Pizzinelli, Paolo; Castiglioni, Paolo; Pigozzi, Fabio; Pagani, Massimo; Parati, Gianfranco

2006-05-01

One of the most important features of prolonged weightlessness is a progressive impairment of muscular function with a consequent decrease in exercise capacity. We tested the hypothesis that the impairment in musculo-skeletal function that occurs in microgravity results in a potentiation of the muscle metaboreflex mechanism and also affects baroreflex modulation of heart rate (HR) during exercise. Four astronauts participating in the 16 day Columbia shuttle mission (STS-107) were studied 72-71 days before launch and on days 12-13 in-flight. The protocol consisted of 6 min bicycle exercise at 50% of individual V(o2,max) followed by 4 min of postexercise leg circulatory occlusion (PECO). At rest, systolic (S) and diastolic (D) blood pressure (BP), R-R interval and baroreflex sensitivity (BRS) did not differ significantly between pre- and in-flight measurements. Both pre- and in-flight, SBP increased and R-R interval and BRS decreased during exercise, whereas DBP did not change. During PECO preflight, SBP and DBP were higher than at rest, whereas R-R interval and BRS recovered to resting levels. During PECO in-flight, SBP and DBP were significantly higher whereas R-R interval and BRS remained significantly lower than at rest. The part of the SBP response (delta) that was maintained by PECO was significantly greater during spaceflight than before (34.5 +/- 8.8 versus 13.8 +/- 11.9 mmHg, P = 0.03). The tachycardic response to PECO was also significantly greater during spaceflight than preflight (-141.5 +/- 25.2 versus - 90.5 +/- 33.3 ms, P = 0.02). This study suggests that the muscle metaboreflex is enhanced during dynamic exercise in space and that the potentiation of the muscle metaboreflex affects the vagally mediated arterial baroreflex contribution to HR control.

BIOPHYSICAL CHARACTERISATION OF THE UNDER-APPRECIATED AND IMPORTANT RELATIONSHIP BETWEEN HEART RATE VARIABILITY AND HEART RATE

PubMed Central

Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

2014-01-01

Heart rate variability (beat-to-beat changes in the RR interval) has attracted considerable attention over the last 30+ years (PubMed currently lists >17,000 publications). Clinically, a decrease in heart rate variability is correlated to higher morbidity and mortality in diverse conditions, from heart disease to foetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated heart rate variability parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart and single sinoatrial nodal cell) in diverse species, combining this with data from previously published papers. We show that regardless of conditions, there is a universal exponential decay-like relationship between heart rate variability and heart rate. Using two biophysical models, we develop a theory for this, and confirm that heart rate variability is primarily dependent on heart rate and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in heart rate variability and altered morbidity and mortality is substantially attributable to the concurrent change in heart rate. This calls for re-evaluation of the findings from many papers that have not adjusted properly or at all for heart rate differences when comparing heart rate variability in multiple circumstances. PMID:25225208

Electrocardiographic findings in athletes: the prevalence of left ventricular hypertrophy and conduction defects.

PubMed

Langdeau, J B; Blier, L; Turcotte, H; O'Hara, G; Boulet, L P

2001-06-01

To determine whether there are electrocardiographic differences or distinctive abnormalities between athletes and sedentary subjects, and to verify the relationship between vagal activity measured by heart rate variability (SD of all normal-to-normal intervals [SDNN]) and possible electrocardiographic abnormalities. Resting electrocardiograms and heart rate variability measurements were performed separately during a single visit on 100 athletes and 50 nonathlete control subjects aged 18 to 55 years. The athletes were from the following various sports disciplines: long-distance running, mountain biking, cross-country skiing, biathlon, speed skating, swimming and triathlon. There were significantly longer RR intervals, PR intervals and QT intervals in athletes than in control subjects (all P<0.05). The QRS complex and QTc did not show significant differences (both P>0.05). The prevalence of left ventricular hypertrophy (LVH) and incomplete right bundle branch block (IRBBB) was 10% and 7%, respectively, in athletes, but these conditions were absent in control subjects; among athletes, 2% presented with both conditions. LVH and IRBBB were more common among long-distance runners (six of 14 and four of 14, respectively) and could be attributed to normal, long term adaptation to intense, repeated exercise. LVH was related to age (P=0.04), whereas IRBBB was influenced by the number of years of training in the respective sports discipline (P=0.03). The mean SDNN value was significantly more elevated in athletes (P=0.0001), reflecting a higher parasympathetic tone than in sedentary control subjects. However, there was no relationship between vagal activity and LVH or IRBBB (both P>0.05).

Comparison of particulate matter dose and acute heart rate variability response in cyclists, pedestrians, bus and train passengers.

PubMed

Nyhan, Marguerite; McNabola, Aonghus; Misstear, Bruce

2014-01-15

Exposure to airborne particulate matter (PM) has been linked to cardiovascular morbidity and mortality. Heart rate variability (HRV) is a measure of the change in cardiac autonomic function, and consistent links between PM exposure and decreased HRV have been documented in studies. This study quantitatively assesses the acute relative variation of HRV with predicted PM dose in the lungs of commuters. Personal PM exposure, HR and HRV were monitored in 32 young healthy cyclists, pedestrians, bus and train passengers. Inhaled and lung deposited PM doses were determined using a numerical model of the human respiratory tract which accounted for varying ventilation rates between subjects and during commutes. Linear mixed models were used to examine air pollution dose and HRV response relationships in 122 commutes sampled. Elevated PM2.5 and PM10 inhaled and lung deposited doses were significantly (p<0.05) associated with decreased HRV indices. Percent declines in SDNN (standard deviation of normal RR intervals) relative to resting, due to an inter-quartile range increase in PM10 lung deposited dose were stronger in cyclists (-6.4%, 95% CI: -11.7, -1.3) and pedestrians (-5.8%, 95% CI: -11.3, -0.5), in comparison to bus (-3.2%, 95% CI: -6.4, -0.1) and train (-1.8%, -7.5, 3.8) passengers. A similar trend was observed in the case of PM2.5 lung deposited dose and results for rMSSD (the square root of the squared differences of successive normal RR intervals) followed similar trends to SDNN. Inhaled and lung deposited doses accounting for varying ventilation rates between modes, individuals and during commutes have been neglected in other studies relating PM to HRV. The findings here indicate that exercise whilst commuting has an influence on inhaled PM and PM lung deposited dose, and these were significantly associated with acute declines in HRV, especially in pedestrians and cyclists. © 2013.

"Polio Eradication" Game May Increase Public Interest in Global Health.

PubMed

Okitika, Toluwalose A; Barnabas, Ruanne V; Rue, Tessa; Weisman, Jordan; Harris, Nathan A; Orenstein, Walter A; Wasserheit, Judith N

2015-06-01

Interactive games that highlight global health challenges and solutions are a potential tool for increasing interest in global health. To test this hypothesis, we developed an interactive "Polio Eradication" (PE) game and evaluated whether playing or watching was associated with increased public interest in global health. The PE game is a life-size, human board game that simulates PE efforts. Four players-a researcher, a transportation expert, a local community coordinator, and a healthcare worker-collaborate as an interdisciplinary team to help limit ongoing and future polio outbreaks in Pakistan, represented on the game board. Participants who played or observed the game and those who did not participate in the game, but visited noninteractive global health exhibits, completed a survey on participation outcomes. We used relative risk regression to examine associations between cofactors and change in global health interest. Three variables predicted increased global health interest among the game participants: Having little or no previous global health knowledge prior to playing the game (risk ratio [RR]=1.28; 95 percent confidence interval [CI], 1.13-1.45), not currently being involved in global health (RR=1.41; 95 percent CI, 1.07-1.85), and visiting Seattle (RR=1.25; 95 percent CI, 1.04-1.51). Our results suggest that a hands-on, interactive game may increase the public's interest in global health, particularly among those with minimal previous knowledge of or involvement in global health activities.

Effects of weather and heliophysical conditions on emergency ambulance calls for elevated arterial blood pressure.

PubMed

Vencloviene, Jone; Babarskiene, Ruta M; Dobozinskas, Paulius; Sakalyte, Gintare; Lopatiene, Kristina; Mikelionis, Nerijus

2015-02-27

We hypothesized that weather and space weather conditions were associated with the exacerbation of essential hypertension. The study was conducted during 2009-2010 in the city of Kaunas, Lithuania. We analyzed 13,475 cards from emergency ambulance calls (EACs), in which the conditions for the emergency calls were made coded I.10-I.15. The Kaunas Weather Station provided daily records of air temperature (T), wind speed (WS), relative humidity, and barometric pressure (BP). We evaluated the associations between daily weather variables and daily number of EACs by applying a multivariate Poisson regression. Unfavorable heliophysical conditions (two days after the active-stormy geomagnetic field or the days with solar WS>600 km/s) increased the daily number of elevated arterial blood pressure (EABP) by 12% (RR=1.12; 95% confidence interval (CI) 1.04-1.21); and WS≥3.5 knots during days of T<1.5 °C and T≥12.5 °C by 8% (RR=1.08; CI 1.04-1.12). An increase of T by 10 °C and an elevation of BP two days after by 10 hPa were associated with a decrease in RR by 3%. An additional effect of T was detected during days of T≥17.5 °C only in females. Women and patients with grade III arterial hypertension at the time of the ambulance call were more sensitive to weather conditions. These results may help in the understanding of the population's sensitivity to different weather conditions.

“Polio Eradication” Game May Increase Public Interest in Global Health

PubMed Central

Barnabas, Ruanne V.; Rue, Tessa; Weisman, Jordan; Harris, Nathan A.; Orenstein, Walter A.

2015-01-01

Abstract Background: Interactive games that highlight global health challenges and solutions are a potential tool for increasing interest in global health. To test this hypothesis, we developed an interactive “Polio Eradication” (PE) game and evaluated whether playing or watching was associated with increased public interest in global health. Materials and Methods: The PE game is a life-size, human board game that simulates PE efforts. Four players—a researcher, a transportation expert, a local community coordinator, and a healthcare worker—collaborate as an interdisciplinary team to help limit ongoing and future polio outbreaks in Pakistan, represented on the game board. Participants who played or observed the game and those who did not participate in the game, but visited noninteractive global health exhibits, completed a survey on participation outcomes. We used relative risk regression to examine associations between cofactors and change in global health interest. Results: Three variables predicted increased global health interest among the game participants: Having little or no previous global health knowledge prior to playing the game (risk ratio [RR]=1.28; 95 percent confidence interval [CI], 1.13–1.45), not currently being involved in global health (RR=1.41; 95 percent CI, 1.07–1.85), and visiting Seattle (RR=1.25; 95 percent CI, 1.04–1.51). Conclusions: Our results suggest that a hands-on, interactive game may increase the public's interest in global health, particularly among those with minimal previous knowledge of or involvement in global health activities. PMID:26182064

Effect of various forms of physical training on the autonomic nervous system activity in patients with acute myocardial infarction.

PubMed

Daniłowicz-Szymanowicz, Ludmiła; Figura-Chmielewska, Monika; Ratkowski, Wojciech; Raczak, Grzegorz

2013-01-01

A shift in the dynamic autonomic nervous system (ANS) balance towards sympathetic activity in patients with acute myocardial infarction (AMI) predisposes them to life-threatening ventricular arrhythmias. Improvement of unfavourable changes in ANS can be expected in such patients as a result of physical training. A beneficial shift in ANS balance towards parasympathetic activity could be confirmed by demonstrating increased baroreceptor reflex sensitivity (BRS) as well as favourable changes in heart rate variability (HRV) parameters. To analyse the effect of different forms of physical training on ANS activity in patients with AMI after hospital discharge. The study included 38 patients with AMI (aged 59 ± 8 years) subjected to 2-month exercise training. Group 1 (n = 19)underwent 3-week supervised in-hospital cardiac rehabilitation followed by 5-week home-based training, and Group 2 (n = 19) underwent 8-week home-based training. BRS and HRV were determined based on a 10-min recording of systolic arterial pressure and the cardiac cycle. Measurements were performed one day before discharge (R1) and after 2 months of training (R2). A significant increase in the mean values of TP (total power), HF (high frequency power), rMSSD (square root of the mean of the squared differences between successive R-R intervals), and pNN50 (proportion of differences between successive R-R intervals that are greater than 50 ms) was observed in the overall study group, along with trends for higher SDNN (standard deviation of the mean of sinus rhythm R-R intervals) and HFnu (normalised HF power), and for lower LFnu (normalised LF power). Additionally, a significant increase in BRS (from 2.2 ± 0.6 to 5.1 ± 2.2 ms/mm Hg, p = 0.01) was found in patients with baseline BRS ≤ 3 ms/mm Hg. A significant increase in rMSSD, pNN50, HF and HFnu, as well as a decrease in LFnu and LF/HF (LF to HF ratio) was observed in Group 1. In contrast, a significant increase in BRS was noted in Group 2. Various forms of 2-month physical training led to a favourable shift in autonomic balance towards parasympathetic activity. Our findings suggest a clinically important effect of physical activity in patients after AMI.

Difference in human cardiovascular response between upright and supine recovery from upright cycle exercise.

PubMed

Takahashi, T; Okada, A; Saitoh, T; Hayano, J; Miyamoto, Y

2000-02-01

Cardiovascular responses were examined in seven healthy male subjects during 10 min of recovery in the upright or supine position following 5 min of upright cycle exercise at 80% peak oxygen uptake. An initial rapid decrease in heart rate (fc) during the early phase of recovery followed by much slower decrease was observed for both the upright and supine positions. The average fc at the 10th min of recovery was significantly lower (P < 0.05) in the supine position than in the upright position, while they were both significantly greater than the corresponding pre-exercise levels (each P < 0.05). Accordingly, the amplitude of the high frequency (HF) component of R-R interval variability (by spectrum analysis) in both positions was reduced with a decrease in mean R-R interval, the relationship being expressed by a regression line--mean R-R interval = 0.006 x HF amplitude + 0.570 (r = 0.905, n = 28, P < 0.001). These results would suggest that the slower reduction in fc following the initial rapid reduction in both positions is partly attributable to a retardation in the restoration of the activity of the cardiac parasympathetic nervous system. Post-exercise upright stroke volume (SV, by impedance cardiography) decreased gradually to just below the pre-exercise level, whereas post-exercise supine SV increased markedly to a level similar to that at rest before exercise. The resultant cardiac output (Qc) and the total peripheral vascular resistance (TPR) in the upright and supine positions returned gradually to their respective pre-exercise levels in the corresponding positions. At the 10th min of recovery, both average SV and Qc were significantly greater (each P < 0.005) in the supine than in the upright position, while average TPR was significantly lower (P < 0.05) in the supine than in the upright position. In contrast, immediately after exercise, mean blood pressure dropped markedly in both the supine and upright positions, and their levels at the 10th min of recovery were similar. Therefore we concluded that arterial blood pressure is maintained relatively constant through various compensatory mechanisms associated with fc, SV, Qc, and TPR during rest and recovery in different body positions.

RR Lyrae type stars

NASA Astrophysics Data System (ADS)

Samus, N. N.

Basic observational data on RR Lyrae type stars are reviewed. It is noted that these stars are used widely to investigate the structure and kinematics of the spherical and intermediate components of the Galaxy, with correct data on the absolute magnitude of these variables being decisive. Attention is given to the relationship between the orbit eccentricity and inclination of osculating RR Lyrae type stars in the Galaxy and their metallicity index.

QT correction formulas and laboratory analysis on patients with metabolic syndrome and diabetes

NASA Astrophysics Data System (ADS)

Wong, Sara; Rivera, Pedro; Rodríguez, María. G.; Severeyn, Érika; Altuve, Miguel

2013-11-01

This article presents a study of ventricular repolarization in diabetic and metabolic syndrome subjects. The corrected QT interval (QTc) was estimated using four correction formulas commonly employed in the literature: Bazett, Fridericia, Framingham and Hodges. After extracting the Q, R and T waves from the electrocardiogram of 52 subjects (19 diabetic, 15 with metabolic syndrome and 18 control), using a wavelet-based approach, the RR interval and QT interval were determined. Then, QTc interval was computed using the formulas previously mentioned. Additionally, laboratory test (fasting glucose, cholesterol, triglycerides) were also evaluated. Results show that metabolic syndrome subjects have normal QTc. However, a longer QTc in this population may be a sign of future complication. The corrected QT interval by Fridericia's formula seems to be the most appropriated for metabolic syndrome subjects (low correlation coefficient between RR and QTc). Significant differences were obtained in the blood glucose and triglyceride levels, principally due to the abnormal sugar metabolization of metabolic syndrome and diabetic subjects. Further studies are focused on the acquisition of a larger database of metabolic syndrome and diabetics subjects and the repetition of this study using other populations, like high performance athletes.

Pesticide leaching via subsurface drains in different hydrologic situations

NASA Astrophysics Data System (ADS)

Zajíček, Antonín; Fučík, Petr; Liška, Marek; Dobiáš, Jakub

2017-04-01

esticides and their degradates in tile drainage waters were studied in two small, predominantly agricultural, tile-drained subcatchments in the Bohemian-Moravian Highlands, Czech Republic. The goal was to evaluate their occurence and the dymamics of their concentrations in drainage waters in different hydrologic situations using discharge and concentration monitoring together with 18O and 2H isotope analysis for Mean Residence Time (MRT) estimation and hydrograph separations during rainfall - runoff (R-R) events. The drainage and stream discharges were measured continuously at the closing outlets of three drainage groups and one small stream. During periods of prevailing base and interflow, samples were collected manually in two-week intervals for isotope analysis and during the spraying period (March to October) also for pesticide analysis. During R-R events, samples were taken by automatic samplers in intervals varying from 20 min (summer) to 1 hour (winter). To enable isotopic analysis, precipitation was sampled both manually at two-week intervals and also using an automatic rainfall sampler which collected samples of precipitation during the R-R events at 20-min. intervals. The isotopic analysis showed, that MRT of drainage base flow and interflow varies from 2,2 to 3,3 years, while MRT of base flow and interflow in surface stream is several months. During R-R events, the proportion of event water varied from 0 to 60 % in both drainage and surface runoff. The occurrence of pesticides and their degradates in drainage waters is strongly dependent on the hydrologic situation. While degradates were permanently present in drainage waters in high but varying concentrations according to instantaneous runoff composition, parent matters were detected almost exclusively during R-R events. In periods with prevailing base flow and interflow (grab samples), especially ESA forms of chloracetanilide degradates occured in high concentrations in all samples. Average sum of degradates varried between 1 730 - 5 760 ng/l. During R-R events, pesticide concentration varried according to runoff composition and time between sprayng and event. Event with no protortiom of event water in drainage runoff were typical by incereas in degradates concentrations (up to 20 000ng/l) and none or low occurence of parent matters. Events with significant event water proportion in drainage runoff were characterised by decrease in degradates concentrations and (when event happened soon affter spraying) by presence of paternal pesticides in drinage runoff. Instanteous concentrations of paren matters can be extremely high in that causes, up to 23 000 ng/l in drainage waters and up to 40 000 ng/l in small stream. Above results suggest that drainage systems could act as significant source of pesticide leaching. When parent compounds leaches via tile drainage systems, there are some border conditions that must exist together such as the occurence of R-R event soon after the pests application and the presence of event water (or water with short residence time in the catchment) in the drainage runoff.

Gender, Race, and Survival: A Study in Non-Small-Cell Lung Cancer Brain Metastases Patients Utilizing the Radiation Therapy Oncology Group Recursive Partitioning Analysis Classification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Videtic, Gregory M.M., E-mail: videtig@ccf.or; Reddy, Chandana A.; Chao, Samuel T.

Purpose: To explore whether gender and race influence survival in non-small-cell lung cancer (NSCLC) in patients with brain metastases, using our large single-institution brain tumor database and the Radiation Therapy Oncology Group recursive partitioning analysis (RPA) brain metastases classification. Methods and materials: A retrospective review of a single-institution brain metastasis database for the interval January 1982 to September 2004 yielded 835 NSCLC patients with brain metastases for analysis. Patient subsets based on combinations of gender, race, and RPA class were then analyzed for survival differences. Results: Median follow-up was 5.4 months (range, 0-122.9 months). There were 485 male patients (M)more » (58.4%) and 346 female patients (F) (41.6%). Of the 828 evaluable patients (99%), 143 (17%) were black/African American (B) and 685 (83%) were white/Caucasian (W). Median survival time (MST) from time of brain metastasis diagnosis for all patients was 5.8 months. Median survival time by gender (F vs. M) and race (W vs. B) was 6.3 months vs. 5.5 months (p = 0.013) and 6.0 months vs. 5.2 months (p = 0.08), respectively. For patients stratified by RPA class, gender, and race, MST significantly favored BFs over BMs in Class II: 11.2 months vs. 4.6 months (p = 0.021). On multivariable analysis, significant variables were gender (p = 0.041, relative risk [RR] 0.83) and RPA class (p < 0.0001, RR 0.28 for I vs. III; p < 0.0001, RR 0.51 for II vs. III) but not race. Conclusions: Gender significantly influences NSCLC brain metastasis survival. Race trended to significance in overall survival but was not significant on multivariable analysis. Multivariable analysis identified gender and RPA classification as significant variables with respect to survival.« less

Therapeutic effect of erythropoietin in patients with traumatic brain injury: a meta-analysis of randomized controlled trials.

PubMed

Liu, Wen-Chao; Wen, Liang; Xie, Tao; Wang, Hao; Gong, Jiang-Biao; Yang, Xiao-Feng

2017-07-01

OBJECTIVE Erythropoietin (EPO) exerts a neuroprotective effect in animal models of traumatic brain injury (TBI). However, its effectiveness in human patients with TBI is unclear. In this study, the authors conducted the first meta-analysis to assess the effectiveness and safety of EPO in patients with TBI. METHODS In December 2015, a systematic search was performed of PubMed, Web of Science, MEDLINE, Embase, the Cochrane Library databases, and Google Scholar. Only English-language publications of randomized controlled trials (RCTs) using EPO in patients with TBI were selected for analysis. The assessed outcomes included mortality, favorable neurological outcome, hospital stay, and associated adverse effects. Continuous variables were presented as mean difference (MD) with a 95% confidence interval (CI). Dichotomous variables were presented as risk ratio (RR) or risk difference (RD) with a 95% CI. Statistical heterogeneity was examined using both I 2 and chi-square tests. RESULTS Of the 346 studies identified in the search, 5 RCTs involving 915 patients met the inclusion criteria. The overall results demonstrated that EPO significantly reduced mortality (RR 0.69, 95% CI 0.49-0.96, p = 0.03) and shortened the hospitalization time (MD -7.59, 95% CI -9.71 to -5.46, p < 0.0001) for patients with TBI. Pooled results of favorable outcome (RR 1.00, 95% CI 0.88-1.15, p = 0.97) and deep vein thrombosis (DVT; RD 0.00, 95% CI -0.05 to 0.05, p = 1.00) did not show a significant difference. CONCLUSIONS The authors suggested that EPO is beneficial for patients with TBI in terms of reducing mortality and shortening hospitalization time without increasing the risk of DVT. However, its effect on improving favorable neurological outcomes did not reach statistical significance. Therefore, more well-designed RCTs are necessary to ascertain the optimum dosage and time window of EPO treatment for patients with TBI.

[Socioeconomic inequalities and infant mortality in Bolivia].

PubMed

Maydana, Edgar; Serral, Gemma; Borrell, Carme

2009-05-01

To evaluate socioeconomic inequalities and its relation to infant mortality in Bolivia's municipalities in 2001. An ecological study based on data from the 2001 National Census on Population and Housing (Censo Nacional de Población y Vivienda) covering the 327 municipalities in Bolivia's nine departments. The dependent variable was the infant mortality rate (IMR); the independent variables were indirect socioeconomic indicators (the percentage of illiterates older than 15 years of age, and the building materials and sanitation features of the houses). The geographic distribution of each indicator was determined and the associations between IMR and each socioeconomic indicator were calculate using Spearman's rank correlation coefficient and adjusted with Poisson regression models. The resulting IMR for Bolivia in 2001 was 67 per 1000 live births. Rates ranged from <0.1 per 1000 live births in the Magdalena municipality, Beni department, to 170.0 per 1000 live births in the Caripuyo municipality, Potosí department. The mean rate of illiteracy per municipality was 17.5%; the mean percentage of houses without running water was 90.4%, and for those lacking sanitation services, 67.6%. The IMR was inversely associated with all of the socioeconomic indicators studied. The highest relative risk was found in housing without sanitation services. Multifactorial models adjusted for illiteracy showed that the following indicators were still strongly associated with the IMR: no sanitation services (Relative risk (RR)=1.54; 95% Confidence Interval (95%CI)=1.38-1.66); adobe, stone, or mud walls (RR=1.54; 95%CI: 1.43-1.67); and, corrugated metal, straw, or palm branch roof (RR=1.34; 95%CI: 1.26-1.43). A significant association was found between poor socioeconomic status and high IMR in Bolivia's municipalities in 2001. The municipalities in the country's central and southeastern areas had lower socioeconomic status and higher IMR. The lack of education, absence of basic sanitation, and precarious housing conditions were key factors that tripled the risk of death.

HST/ACS Observations of RR Lyrae Stars in Six Ultra-Deep Fields of M31

NASA Technical Reports Server (NTRS)

Jeffery, E. J.; Smith, E.; Brown, T. M.; Sweigart, A. V.; Kalirai, J. S.; Ferguson, H. C.; Guhathakurta, P.; Renzini, A.; Rich, R. M.

2010-01-01

We present HST/ACS observations of RR Lyrae variable stars in six ultra deep fields of the Andromeda galaxy (M31), including parts of the halo, disk, and giant stellar stream. Past work on the RR Lyrae stars in M31 has focused on various aspects of the stellar populations that make up the galaxy s halo, including their distances and metallicities. This study builds upon this previous work by increasing the spatial coverage (something that has been lacking in previous studies) and by searching for these variable stars in constituents of the galaxy not yet explored. Besides the 55 RR Lyrae stars we found in our initial field located 11kpc from the galactic nucleus, we find additional RR Lyrae stars in four of the remaining five ultra deep fields as follows: 21 in the disk, 24 in the giant stellar stream, 3 in the halo field 21kpc from the galactic nucleus, and 5 in one of the halo fields at 35kpc. No RR Lyrae were found in the second halo field at 35kpc. The RR Lyrae populations of these fields appear to mostly be of Oosterhoff I type, although the 11kpc field appears to be intermediate or mixed. We will discuss the properties of these stars including period and reddening distributions. We calculate metallicities and distances for the stars in each of these fields using different methods and compare the results, to an extent that has not yet been done. We compare these methods not just on RR Lyrae in our M31 fields, but also on a data set of Milky Way field RR Lyrae stars.

ART Attrition across Health Facilities Implementing Option B+ in Haiti.

PubMed

Myrtil, Martine Pamphile; Puttkammer, Nancy; Gloyd, Stephen; Robinson, Julia; Yuhas, Krista; Domercant, Jean Wysler; Honoré, Jean Guy; Francois, Kesner

2018-01-01

Describing factors related to high attrition is important in order to improve the implementation of the Option B+ strategy in Haiti. We conducted a retrospective cohort study to describe the variability of antiretroviral therapy (ART) retention across health facilities among pregnant and lactating women and assess for differences in ART retention between Option B+ clients and other ART patients. There were 1989 Option B+ clients who initiated ART in 45 health facilities. The percentage of attrition varied from 9% to 81% across the facilities. The largest health facilities had 38% higher risk of attrition (relative risk [RR]: 1.38, 95% confidence interval [CI]: 1.08-1.77, P = .009). Private institutions had 18% less risk of attrition (RR: 0.82, 95% CI: 0.70-0.96, P = .020). Health facilities located in the West department and the South region had lower risk of attrition. Being on treatment in a large or public health facility or a facility located in the North region was a significant risk factor associated with high attrition among Option B+ clients. The implementation of the Option B+ strategy must be reevaluated in order to effectively eliminate mother-to-child HIV transmission.

Predictive factors of long-term colorectal cancer survival after ultrasound-controlled ablation of hepatic metastases.

PubMed

Hernández-Socorro, Carmen Rosa; Saavedra, Pedro; Ramírez Felipe, José; Bohn Sarmiento, Uriel; Ruiz-Santana, Sergio

2017-04-21

The risk factors associated to long-term survival were assessed in patients with liver metastases of colorectal carcinoma undergoing ablative therapies. Single-centre cohort study, retrospectively analysed and prospectively collected consecutive patients with unresectable metastatic liver disease of colorectal carcinoma treated with ablative therapies between 1996 and 2013. Factors associated with survival time were identified using Cox's proportional hazard model with time-dependent covariates. A forward variable selection based on Akaike information criterion was performed. Relative risk and 95% confidence intervals for each factor were calculated. Statistical significance was set as P<.05. Seventy-five patients with liver metastases of colorectal cancer, with a mean age of 65.6 (10.3) underwent 106 treatments. Variables selected were good quality of life (RR 0.308, 95% CI 0.150-0.632) and tumour extension (RR 3.070, 95% CI 1.776-5.308). The median overall survival was 18.5 months (95% CI 17.4-24.4). The survival prognosis in median was 13.5 vs. 23.4 months for patients with and without tumour extension, and 23.0 vs. 12.8 months for patients with good and fair or poor quality of life, respectively. Good quality of life and tumour extension were the only statistically significant predictors of long-term survival in patients of colorectal carcinoma with liver metastatic disease undergoing ablative treatment with ultrasound. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

Is meat consumption associated with depression? A meta-analysis of observational studies.

PubMed

Zhang, Yi; Yang, Ye; Xie, Ming-Sheng; Ding, Xiang; Li, Hui; Liu, Zhi-Chen; Peng, Shi-Fang

2017-12-28

A number of epidemiological studies have examined the effect of meat consumption on depression. However, no conclusion has been reached. The aim of this study was to examine the relationship between meat consumption and depression. The electronic databases of PUBMED and EMBASE were searched up to March 2017, for observational studies that examined the relationship between meat consumption and depression. The pooled odds ratio (OR) for the prevalence of depression and the relative risk (RR) for the incidence of depression, as well as their corresponding 95% confidence interval (CI), were calculated respectively (the highest versus the lowest category of meat consumption). A total of eight observational studies (three cross-sectional, three cohort and two case-control studies) were included in this meta-analysis. Specifically, six studies were related to the prevalence of depression, and the overall multi-variable adjusted OR suggested no significant association between meat consumption and the prevalence of depression (OR = 0.89, 95% CI: 0.65 to 1.22; P = 0.469). In contrast, for the three studies related to the incidence of depression, the overall multi-variable adjusted RR evidenced an association between meat consumption and a moderately higher incidence of depression (RR = 1.13, 95% CI: 1.03 to 1.24; P = 0.013). Meat consumption may be associated with a moderately higher risk of depression. However, it still warrants further studies to confirm such findings due to the limited number of prospective studies.

Pediatric magnet ingestions: the dark side of the force.

PubMed

Brown, Julie C; Otjen, Jeffrey P; Drugas, George T

2014-05-01

Pediatric magnet ingestions are increasing. Commercial availability of rare-earth magnets poses a serious health risk. This study defines incidence, characteristics, and management of ingestions over time. Cases were identified by searching radiology reports from June 2002 to December 2012 at a children's hospital and verified by chart and imaging review. Relative risk (RR) regressions determined changes in incidence and interventions over time. In all, 98% of ingestions occurred since 2006; 57% involved multiple magnets. Median age was 8 years (range 0 to 18); 0% of single and 56% of multiple ingestions required intervention. Compared with 2007 to 2009, ingestions increased from 2010 to 2012 (RR = 1.9, 95% confidence interval 1.2 to 3.0). Intervention proportion was unchanged (RR = .94, 95% confidence interval .4 to 2.2). Small spherical magnets comprised 26.8% of ingestions since 2010; 86% involved multiple magnets and 47% required intervention. Pediatric magnet ingestions and interventions have increased. Multiple ingestions prompt more imaging and surgical interventions. Magnet safety standards are needed to decrease risk to children. Copyright © 2014 Elsevier Inc. All rights reserved.

Physiological Parameter Monitoring from Optical Recordings with a Mobile Phone

PubMed Central

Scully, Christopher G.; Lee, Jinseok; Meyer, Joseph; Gorbach, Alexander M.; Granquist-Fraser, Domhnull; Mendelson, Yitzhak

2012-01-01

We show that a mobile phone can serve as an accurate monitor for several physiological variables, based on its ability to record and analyze the varying color signals of a fingertip placed in contact with its optical sensor. We confirm the accuracy of measurements of breathing rate, cardiac R-R intervals, and blood oxygen saturation, by comparisons to standard methods for making such measurements (respiration belts, ECGs, and pulse-oximeters, respectively). Measurement of respiratory rate uses a previously reported algorithm developed for use with a pulse-oximeter, based on amplitude and frequency modulation sequences within the light signal. We note that this technology can also be used with recently developed algorithms for detection of atrial fibrillation or blood loss. PMID:21803676

Non stationary analysis of heart rate variability during the obstructive sleep apnea.

PubMed

Méndez, M O; Bianchi, A M; Cerutti, S

2004-01-01

Characteristic fluctuations of the heart rate are found during obstructive sleep apnea (OSA), bradycardia in apneonic phase and tachycardia at the recovery of ventilation. In order to assess its autonomic response, in this study, the time-frequency distribution of Born-Jordan and evolutive Poincare plots are used. From Physionet was taken a database with records of ECG and respiratory signals. During the OSA all spectral indexes presented oscillations correspondent to the changes between brady and tachycardia of the RR intervals as well as greater values than during control epochs. Born-Jordan distribution and evolutive Poincare plots could help to characterize and develop an index for the evaluation of OSA. Very low frequency could also be a good index of OSA.

Low dimensional model of heart rhythm dynamics as a tool for diagnosing the anaerobic threshold

NASA Astrophysics Data System (ADS)

Anosov, O. L.; Butkovskii, O. Ya.; Kadtke, J.; Kravtsov, Yu. A.; Protopopescu, V.

1997-05-01

We report preliminary results on describing the dependence of the heart rhythm variability on the stress level by using qualitative, low dimensional models. The reconstruction of macroscopic heart models yielding cardio cycles (RR-intervals) duration was based on actual clinical data. Our results show that the coefficients of the low dimensional models are sensitive to metabolic changes. In particular, at the transition between aerobic and aerobic-anaerobic metabolism, there are pronounced extrema in the functional dependence of the coefficients on the stress level. This strong sensitivity can be used to design an easy indirect method for determining the anaerobic threshold. This method could replace costly and invasive traditional methods such as gas analysis and blood tests.

RR Lyrae Variables in Stellar Systems

NASA Astrophysics Data System (ADS)

Smith, Horace A.; Catelan, Márcio; Clementini, Gisella

2009-09-01

The pioneering studies of RR Lyrae stars in globular clusters by Oosterhoff and by Sawyer Hogg in the 1930s and 1940s called attention to interesting systematic differences among RR Lyrae populations in different systems. When such studies were extended to the dwarf spheroidal companions of the Milky Way in the 1960s, it was found that the average properties of their RR Lyrae stars were often different from those that had previously been observed in globular clusters. Observations of RR Lyrae stars have now extended to the Andromeda Galaxy and other Local Group systems, with still greater variety being apparent. Our understanding of the reasons for these differences among the RR Lyrae populations in different systems is by no means complete, but properties of RR Lyrae stars within these different systems are tied to differing horizontal branch morphologies and also shed light upon scenarios for the formation of the Galaxy.

Anxiety, depression and autonomic nervous system dysfunction in hypertension.

PubMed

Bajkó, Zoltán; Szekeres, Csilla-Cecília; Kovács, Katalin Réka; Csapó, Krisztina; Molnár, Sándor; Soltész, Pál; Nyitrai, Erika; Magyar, Mária Tünde; Oláh, László; Bereczki, Dániel; Csiba, László

2012-06-15

This study examined the relationship between autonomic nervous system dysfunction, anxiety and depression in untreated hypertension. 86 newly diagnosed hypertensive patients and 98 healthy volunteers were included in the study. The psychological parameters were assessed with Spielberger State-Trait Anxiety Inventory and Beck Depression Inventory by a skilled psychologist. Autonomic parameters were examined during tilt table examination (10min lying position, 10min passive tilt). Heart rate variability (HRV) was calculated by autoregressive methods. Baroreflex sensitivity (BRS) was calculated by non-invasive sequence method from the recorded beat to beat blood pressure values and RR intervals. Significantly higher state (42.6±9.3 vs. 39.6±10.7 p=0.05) and trait (40.1±8.9 vs. 35.1±8.6, p<0.0001) anxiety scores were found in the hypertension group. There was no statistically significant difference in the depression level. LF-RRI (Low Frequency-RR interval) of HRV in passive tilt (377.3±430.6 vs. 494.1±547, p=0.049) and mean BRS slope (11.4±5.5 vs. 13.2±6.4, p=0.07) in lying position were lower in hypertensives. Trait anxiety score correlates significantly with sympatho/vagal balance (LF/HF-RRI) in passive tilt position (Spearman R=-0.286, p=0.01). Anxiety could play a more important role than depression in the development of hypertension. Altered autonomic control of the heart could be one of the pathophysiological links between hypertension and psychological factors. Copyright © 2012 Elsevier B.V. All rights reserved.

Cardiac and autonomic nerve function after reduced-intensity stem cell transplantation for hematologic malignancy in patients with pre-transplant cardiac dysfunction.

PubMed

Nakane, Takahiko; Nakamae, Hirohisa; Muro, Takashi; Yamagishi, Hiroyuki; Kobayashi, Yoshiki; Aimoto, Mizuki; Sakamoto, Erina; Terada, Yoshiki; Nakamae, Mika; Koh, Ki-Ryang; Yamane, Takahisa; Yoshiyama, Minoru; Hino, Masayuki

2009-09-01

Recent reports have shown that cardiomyopathy caused by hemochromatosis in severe aplastic anemia is reversible after reduced-intensity allogeneic stem-cell transplantation (RIST). We comprehensively evaluated cardiac and autonomic nerve function to determine whether cardiac dysfunction due to causes other than hemochromatosis is attenuated after RIST. In five patients with cardiac dysfunction before transplant, we analyzed the changes in cardiac and autonomic nerve function after transplant, using electrocardiography (ECG), echocardiography, radionuclide angiography (RNA), serum markers, and heart rate variability (HRV), before and up to 100 days after transplant. There was no significant improvement in cardiac function in any patient and no significant alteration in ECG, echocardiogram, RNA, or serum markers. However, on time-domain analysis of HRV, the SD of normal-to-normal RR intervals (SDNN) and the coefficient of variation of the RR interval (CVRR) decreased significantly 30 and 60 days after transplant (P = 0.04 and 0.01, respectively). Similarly, on frequency-domain analysis of HRV, low and high frequency power (LF and HF) significantly and temporarily decreased (P = 0.003 and 0.03, respectively). Notably, in one patient who had acute heart failure after transplantation, the values of SDNN, CVRR, r-MSSD, LF, and HF at 30 and 60 days after transplantation were the lowest of all the patients. In conclusion, this study suggests that (a) RIST is well-tolerated in patients with cardiac dysfunction, but we cannot expect improvement in cardiac dysfunction due to causes other than hemochromatosis; and (b) monitoring HRV may be useful in predicting cardiac events after RIST.

Variable Stars in the Field of the Hydra II Ultra-Faint Dwarf Galaxy

NASA Astrophysics Data System (ADS)

Vivas, Anna Katherina; Olsen, Knut A.; Blum, Robert D.; Nidever, David L.; Walker, Alistair R.; Martin, Nicolas; Besla, Gurtina; Gallart, Carme; Van Der Marel, Roeland P.; Majewski, Steven R.; Munoz, Ricardo; Kaleida, Catherine C.; Saha, Abhijit; Conn, Blair; Jin, Shoko

2016-06-01

We searched for variable stars in Hydra II, one of the recently discovered ultra-faint dwarf satellites of the Milky Way, using gri time-series obtained with the Dark Energy Camera (DECam) at Cerro Tololo Inter-American Observatory, Chile. We discovered one RR Lyrae star in the galaxy which was used to derive a distance of 154±8 kpc to this system and to re-calculate its absolute magnitude and half-light radius.A comparison with other RR Lyrae stars in ultra-faint systems indicates similar pulsational properties among them, which are different to those found among halo field stars and those in the largest of the Milky Way satellites. We also report the discovery of 31 additional short period variables in the field of view (RR Lyrae, SX Phe, eclipsing binaries, and a likely anomalous cepheid) which are likely not related with Hydra II.

Photographic photometry of RR Lyrae variables in the globular cluster M15

NASA Astrophysics Data System (ADS)

Bingham, E. A.; Cacciari, C.; Dickens, R. J.; Pecci, F. F.

1984-08-01

Light curves in B and V bands are presented for 56 RR Lyrae variables in the Oosterhoff Group II globular cluster M15. Correlations between light curves parameters are obtained and their significance is discussed. An accurate assessment of the sources of error in the period-color relation has permitted the prediction of the range of masses among the variables with a dispersion of about 0.025 solar mass. The period color relation was used to derive a mass-to-light ratio of -1.92 (+ or - 0.03). The luminosity observed in M15 implies an age a few billion years less than current estimates. The morphology of the SG tracks indicates that many of the RR Lyraes in M15 begin their horizontal evolution within the instability strip, spending much longer in the center of the strip than M3-like clusters which evolve more rapidly bluewards across the strip.

Systolic blood pressure but not electrocardiogram QRS duration is associated with heart rate variability (HRV): a cross-sectional study in rural Australian non-diabetics.

PubMed

Lee, Yvonne Yin Leng; Jelinek, Herbert F; McLachlan, Craig S

2017-01-01

A positive correlation between ECG derived QRS duration and heart rate variability (HRV) parameters had previously been reported in young healthy adults. We note this study used a narrow QRS duration range, and did not adjust for systolic blood pressure. Our aims are to investigate associations between systolic blood pressure (SBP), QRS duration and HRV in a rural aging population. A retrospective cross sectional population was obtained from the CSU Diabetes Screening Research Initiative data base where 200 participants had no diabetes or pre-diabetes. SBP data were matched with ECG derived QRS duration and HRV parameters. HRV parameters were calculated from R-R intervals. Resting 12-lead electrocardiograms were obtained from each subject using a Welch Allyn PC-Based ECG system. Pearson correlation analysis revealed no statistically significant associations between HRV parameters and QRS duration. No significant mean differences in HRV parameter subgroups across defined QRS cut-offs were found. SBP > 146 mmHg was associated with increasing QRS durations, however this association disappeared once models were adjusted for age and gender. SBP was also significantly associated with a number of HRV parameters using Pearson correlation analysis, including high frequency (HF) ( p  < 0.05), HFln ( p  < 0.02), RMSDD ( p  < 0.02) and non-linear parameters; ApEN ( p  < 0.001) were negatively correlated with increasing SBP while the low frequency to high frequency ratio (LF/HF) increased with increasing SBP ( p  < 0.03). Our results do not support associations between ECG derived R-R derived HRV parameters and QRS duration in aging populations. We suggest that ventricular conduction as determined by QRS duration is independent of variations in SA-node heart rate variability.

Fetal electrocardiogram (ECG) for fetal monitoring during labour.

PubMed

Neilson, James P

2015-12-21

Hypoxaemia during labour can alter the shape of the fetal electrocardiogram (ECG) waveform, notably the relation of the PR to RR intervals, and elevation or depression of the ST segment. Technical systems have therefore been developed to monitor the fetal ECG during labour as an adjunct to continuous electronic fetal heart rate monitoring with the aim of improving fetal outcome and minimising unnecessary obstetric interference. To compare the effects of analysis of fetal ECG waveforms during labour with alternative methods of fetal monitoring. The Cochrane Pregnancy and Childbirth Group's Trials Register (latest search 23 September 2015) and reference lists of retrieved studies. Randomised trials comparing fetal ECG waveform analysis with alternative methods of fetal monitoring during labour. One review author independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. One review author assessed the quality of the evidence using the GRADE approach. Seven trials (27,403 women) were included: six trials of ST waveform analysis (26,446 women) and one trial of PR interval analysis (957 women). The trials were generally at low risk of bias for most domains and the quality of evidence for ST waveform analysis trials was graded moderate to high. In comparison to continuous electronic fetal heart rate monitoring alone, the use of adjunctive ST waveform analysis made no obvious difference to primary outcomes: births by caesarean section (risk ratio (RR) 1.02, 95% confidence interval (CI) 0.96 to 1.08; six trials, 26,446 women; high quality evidence); the number of babies with severe metabolic acidosis at birth (cord arterial pH less than 7.05 and base deficit greater than 12 mmol/L) (average RR 0.72, 95% CI 0.43 to 1.20; six trials, 25,682 babies; moderate quality evidence); or babies with neonatal encephalopathy (RR 0.61, 95% CI 0.30 to 1.22; six trials, 26,410 babies; high quality evidence). There were, however, on average fewer fetal scalp samples taken during labour (average RR 0.61, 95% CI 0.41 to 0.91; four trials, 9671 babies; high quality evidence) although the findings were heterogeneous and there were no data from the largest trial (from the USA). There were marginally fewer operative vaginal births (RR 0.92, 95% CI 0.86 to 0.99; six trials, 26,446 women); but no obvious difference in the number of babies with low Apgar scores at five minutes or babies requiring neonatal intubation, or babies requiring admission to the special care unit (RR 0.96, 95% CI 0.89 to 1.04, six trials, 26,410 babies; high quality evidence). There was little evidence that monitoring by PR interval analysis conveyed any benefit of any sort. The modest benefits of fewer fetal scalp samplings during labour (in settings in which this procedure is performed) and fewer instrumental vaginal births have to be considered against the disadvantages of needing to use an internal scalp electrode, after membrane rupture, for ECG waveform recordings. We found little strong evidence that ST waveform analysis had an effect on the primary outcome measures in this systematic review.There was a lack of evidence showing that PR interval analysis improved any outcomes; and a larger future trial may possibly demonstrate beneficial effects.There is little information about the value of fetal ECG waveform monitoring in preterm fetuses in labour. Information about long-term development of the babies included in the trials would be valuable.

[Differences in the recognition of occupational diseases by sex, occupation and business activity in Spain (1990-2009)].

PubMed

García Gómez, Montserrat; Castañeda López, Rosario; Herrador Ortiz, Zaida; Simón Soria, Fernando

2017-01-09

According to official statistics, men suffer more occupational diseases (OD) than women. Nevertheless, the unequal distribution and participation in the labor markets between men and women should be kept in mind. The purpose was to assess the gender impact in the recognition of OD in Spain, examining interaction and confounding factors. An incidence study of the occupational diseases declared through the official OD reporting forms from 1999 to 2009, provided by the General Subdirectorate of Social and Labor Statistics of the Ministry of Employment and Social Security, was conducted. The variables included were: reporting year, sex, age, occupation and economic activity of the company. Rates and crude relative risks (cRR) by these variables were calculated. Adjusted RR were also computed by using multivariate Poisson regression. During the study period a total of 243,310 OD were reported in Spain, with a sex ratio of men to women of 1.07. Correlation existed between occupation and business activity, thus the OD rates and RR were computed by these variables separately. By occupation, men had a crude RR of 1.067 (95%CI:1.058 to 1.076) versus women, while wen the analysis was adjusted by all the variables, the RR was 0.507 (95%CI:0.502 to 0.512). By economic activity of the company, the sense of risk was reversed too in the adjusted analysis (cRR=1.065, 95%CI:1.056 to 1.074 versus 0.632, 95%CI:0.626 to 0.638). Although crude OD rates were lower in women than in men during the period 1999-2009 in Spain, when these rates were adjusted by company activity or worker occupation, age and year of OD declaration, RRs become almost 50% higher in women than in men for the majority of occupations and types of company activity.

Lower Interbreath Interval Complexity Is Associated With Extubation Failure in Mechanically Ventilated Patients During Spontaneous Breathing Trials

DTIC Science & Technology

2010-06-01

patient tolerated the SBT, then measurement of respiratory rate (RR), rapid shallow breathing index (RSBI), and negative inspiratory force ( NIF ) were...no deaths in either cohort during the study period. The characteristics of the two groups, along with RR, duration of IBI, NIF , and RSBI calculated... NIF , and RSBI did not differ between groups, and that all subjects who were extubated had weaning parameters predictive of success. To explore the

The effects of acupuncture on rates of clinical pregnancy among women undergoing in vitro fertilization: a systematic review and meta-analysis

PubMed Central

Manheimer, Eric; van der Windt, Daniëlle; Cheng, Ke; Stafford, Kristen; Liu, Jianping; Tierney, Jayne; Lao, Lixing; Berman, Brian M.; Langenberg, Patricia; Bouter, Lex M.

2013-01-01

BACKGROUND Recent systematic reviews of adjuvant acupuncture for IVF have pooled heterogeneous trials, without examining variables that might explain the heterogeneity. The aims of our meta-analysis were to quantify the overall pooled effects of adjuvant acupuncture on IVF clinical pregnancy success rates, and evaluate whether study design-, treatment- and population-related factors influence effect estimates. METHODS We included randomized controlled trials that compared needle acupuncture administered within 1 day of embryo transfer, versus sham acupuncture or no adjuvant treatment. Our primary outcome was clinical pregnancy rates. We obtained from all investigators additional methodological details and outcome data not included in their original publications. We analysed sham-controlled and no adjuvant treatment-controlled trials separately, but since there were no large or significant differences between these two subsets, we pooled all trials for subgroup analyses. We prespecified 11 subgroup variables (5 clinical and 6 methodological) to investigate sources of heterogeneity, using single covariate meta-regressions. RESULTS Sixteen trials (4021 participants) were included in the meta-analyses. There was no statistically significant difference between acupuncture and controls when combining all trials [risk ratio (RR) 1.12, 95% confidence interval (CI), 0.96–1.31; I2 = 68%; 16 trials; 4021 participants], or when restricting to sham-controlled (RR 1.02, 0.83–1.26; I2 = 66%; 7 trials; 2044 participants) or no adjuvant treatment-controlled trials (RR 1.22, 0.97–1.52; I2 = 67%; 9 trials; 1977 participants). The type of control used did not significantly explain the statistical heterogeneity (interaction P = 0.27). Baseline pregnancy rate, measured as the observed rate of clinical pregnancy in the control group of each trial, was a statistically significant effect modifier (interaction P < 0.001), and this covariate explained most of the heterogeneity of the effects of adjuvant acupuncture across all trials (adjusted R2 = 93%; I2 residual = 9%). Trials with lower control group rates of clinical pregnancy showed larger effects of adjuvant acupuncture (RR 1.53, 1.28–1.84; 7 trials; 1732 participants) than trials with higher control group rates of clinical pregnancy (RR 0.90, 0.80–1.01; 9 trials; 2289 participants). The asymmetric funnel plot showed a tendency for the intervention effects to be more beneficial in smaller trials. CONCLUSIONS We found no pooled benefit of adjuvant acupuncture for IVF. The subgroup finding of a benefit in trials with lower, but not higher, baseline pregnancy rates (the only statistically significant subgroup finding in our earlier review) has been confirmed in this update, and was not explained by any confounding variables evaluated. However, this baseline pregnancy rate subgroup finding among published trials requires further confirmation and exploration in additional studies because of the multiple subgroup tests conducted, the risk of unidentified confounders, the multiple different factors that determine baseline rates, and the possibility of publication bias. PMID:23814102

The role of respiratory measures to assess mental load in pilot selection.

PubMed

Grassmann, Mariel; Vlemincx, Elke; von Leupoldt, Andreas; Van den Bergh, Omer

2016-06-01

While cardiovascular measures have a long tradition of being used to determine operator load, responsiveness of the respiratory system to mental load has rarely been investigated. In this study, we assessed basic and variability measures of respiration rate (RR), partial pressure of end-tidal carbon dioxide (petCO2) as well as performance measures in 63 male pilot candidates during completion of a complex cognitive task and subsequent recovery. Mental load was associated with an increase in RR and a decrease in respiratory variability. A significant decrease was also found for petCO2. RR and respiratory variability showed partial and complete effects of recovery, respectively, whereas petCO2 did not return to baseline level. Overall, a good performance was related to a stronger reactivity in RR. Our findings suggest that respiratory parameters would be a useful supplement to common measures for the assessment of mental load in pilot selection. Practitioner Summary: Respiratory measures are a promising yet poorly investigated approach to monitor operator load. For pilot selection, we assessed respiration in response to multitasking in 63 candidates. Task-related changes as well as covariation with performance strongly support the consideration of respiratory parameters when evaluating reactivity to mental load.

Same-sex marriage, autoimmune thyroid gland dysfunction and other autoimmune diseases in Denmark 1989-2008.

PubMed

Frisch, Morten; Nielsen, Nete Munk; Pedersen, Bo Vestergaard

2014-01-01

Autoimmune diseases have been little studied in gay men and lesbians. We followed 4.4 million Danes, including 9,615 same-sex married (SSM) persons, for 47 autoimmune diseases in the National Patient Registry between 1989 and 2008. Poisson regression analyses provided first hospitalization rate ratios (RRs) comparing rates between SSM individuals and persons in other marital status categories. SSM individuals experienced no unusual overall risk of autoimmune diseases. However, the risk of autoimmune thyroid dysfunction was increased, notably Hashimoto's thyroiditis (women(SSM), RR = 2.92; 95% confidence interval (CI) 1.74-4.55) and Graves' disease (men(SSM), RR = 1.88; 95% CI 1.08-3.01). There was also an excess of primary biliary cirrhosis (women(SSM), RR = 4.09; 95% CI 1.01-10.7), and of psoriasis (men(SSM), RR = 2.48; 95% CI 1.77-3.36), rheumatic fever (men(SSM), RR = 7.55; 95% CI 1.87-19.8), myasthenia gravis (men(SSM), RR = 5.51; 95% CI 1.36-14.4), localized scleroderma (men(SSM), RR = 7.16; 95% CI 1.18-22.6) and pemphigoid (men(SSM), RR = 6.56; 95% CI 1.08-20.6), while Dupuytren's contracture was reduced (men(SSM), RR = 0.64; 95% CI 0.39-0.99). The excess of psoriasis was restricted to same-sex married men with HIV/AIDS (men(SSM), RR = 10.5; 95% CI 6.44-15.9), whereas Graves' disease occurred in excess only among same-sex married men without HIV/AIDS (men(SSM), RR = 1.99; 95% CI 1.12-3.22). Lesbians and immunologically competent gay men in same-sex marriage face no unusual overall risk of autoimmune diseases. However, the observed increased risk of thyroid dysfunction in these lesbians and gay men deserves further study.

The role of the Na+/Ca2+ exchanger, INa and ICaL in the genesis of dofetilide-induced torsades de pointes in isolated, AV-blocked rabbit hearts

PubMed Central

Farkas, Attila S; Makra, Péter; Csík, Norbert; Orosz, Szabolcs; Shattock, Michael J; Fülöp, Ferenc; Forster, Tamás; Csanády, Miklós; Papp, Julius Gy; Varró, András; Farkas, András

2009-01-01

Background and purpose: The Na+/Ca2+ exchanger (NCX) may contribute to triggered activity and transmural dispersion of repolarization, which are substrates of torsades de pointes (TdP) type arrhythmias. This study examined the effects of selective inhibition of the NCX by SEA0400 on the occurrence of dofetilide-induced TdP. Experimental approach: Effects of SEA0400 (1 µmol·L−1) on dofetilide-induced TdP was studied in isolated, Langendorff-perfused, atrioventricular (AV)-blocked rabbit hearts. To verify the relevance of the model, lidocaine (30 µmol·L−1) and verapamil (750 nmol·L−1) were also tested against dofetilide-induced TdP. Key results: Acute AV block caused a chaotic idioventricular rhythm and strikingly increased beat-to-beat variability of the RR and QT intervals. SEA0400 exaggerated the dofetilide-induced increase in the heart rate-corrected QT interval (QTc) and did not reduce the incidence of dofetilide-induced TdP [100% in the SEA0400 + dofetilide group vs. 75% in the dofetilide (100 nmol·L−1) control]. In the second set of experiments, verapamil further increased the dofetilide-induced QTc prolongation and neither verapamil nor lidocaine reduced the dofetilide-induced increase in the beat-to-beat variability of the QT interval. However, lidocaine decreased and verapamil prevented the development of dofetilide-induced TdP as compared with the dofetilide control (TdP incidence: 13%, 0% and 88% respectively). Conclusions and implications: Na+/Ca2+ exchanger does not contribute to dofetilide-induced TdP, whereas Na+ and Ca2+ channel activity is involved in TdP genesis in isolated, AV-blocked rabbit hearts. Neither QTc prolongation nor an increase in the beat-to-beat variability of the QT interval is a sufficient prerequisite of TdP genesis in rabbit hearts. PMID:19222480

Comparison of teen driver fatality rates by vehicle type in the United States.

PubMed

Trowbridge, Matthew J; McKay, Mary Pat; Maio, Ronald F

2007-10-01

To compare national fatality rates for teen drivers by vehicle type. Fatality rates were calculated for 16- to 19-year-old drivers by vehicle type using data from the Fatal Analysis Reporting System (1999-2003) and estimates of miles driven from the National Household Transportation Survey (2001). Relative fatality risks for teen drivers of sports utility vehicles (SUVs) and pickups were calculated using passenger cars as a reference. Per vehicle mile driven, the fatality risk for both male and female teens driving SUVs was decreased relative to passenger car drivers (male teens: relative risk [RR], 0.33 [95% confidence interval [CI] = 0.29 to 0.37]; female teens: RR, 0.45 [95% CI = 0.34 to 0.59]). Fatality rates for male teens driving pickups were also lower per mile driven compared with male passenger car drivers (RR, 0.55 [95% CI = 0.51 to 0.60]). Fatality rates for female teens driving pickups and passenger cars were not statistically different but appear potentially higher for pickups (RR, 1.19 [95% CI = 0.98 to 1.44]). Both SUVs and pickups demonstrated significantly higher rates of fatal rollovers than passenger cars. Female adolescent drivers of SUVs and pickups were at particularly high risk for fatal rollovers per vehicle mile driven compared with passenger cars (SUV: RR, 1.88 [95% CI = 1.19 to 2.96]; pickup: RR, 3.42 [95% CI = 2.29 to 5.10]). Fatality rates for teen drivers vary significantly by vehicle type. From 1999 to 2003 in the United States, fatal rollovers were significantly more likely per mile driven for teen drivers of both SUVs and pickups compared with passenger cars. However, overall fatality rates (i.e., all crash types) for teen drivers of SUVs and male drivers of pickups were lower per mile driven than for teen drivers of passenger cars. The results of this ecological analysis cannot predict the individual-level fatality risk for teens driving different vehicle types. However, the significant variability in fatality rates among SUVs, pickups, and passenger cars seen at a population level suggests that vehicle choice should be further explored as a potentially modifiable risk factor in interventions to address teen driver safety.

Primary care physician workforce and Medicare beneficiaries' health outcomes.

PubMed

Chang, Chiang-Hua; Stukel, Therese A; Flood, Ann Barry; Goodman, David C

2011-05-25

Despite a widespread interest in increasing the numbers of primary care physicians to improve care and to moderate costs, the relationship of the primary care physician workforce to patient-level outcomes remains poorly understood. To measure the association between the adult primary care physician workforce and individual patient outcomes. A cross-sectional analysis of the outcomes of a 2007 20% sample of fee-for-service Medicare beneficiaries aged 65 years or older (N = 5,132,936), which used 2 measures of adult primary care physicians (general internists and family physicians) across Primary Care Service Areas (N = 6542): (1) American Medical Association (AMA) Masterfile nonfederal, office-based physicians per total population and (2) office-based primary care clinical full-time equivalents (FTEs) per Medicare beneficiary derived from Medicare claims. Annual individual-level outcomes (mortality, ambulatory care sensitive condition [ACSC] hospitalizations, and Medicare program spending), adjusted for individual patient characteristics and geographic area variables. Marked variation was observed in the primary care physician workforce across areas, but low correlation was observed between the 2 primary care workforce measures (Spearman r = 0.056; P < .001). Compared with areas with the lowest quintile of primary care physician measure using AMA Masterfile counts, beneficiaries in the highest quintile had fewer ACSC hospitalizations (74.90 vs 79.61 per 1000 beneficiaries; relative rate [RR], 0.94; 95% confidence interval [CI], 0.93-0.95), lower mortality (5.38 vs 5.47 per 100 beneficiaries; RR, 0.98; 95% CI, 0.97-0.997), and no significant difference in total Medicare spending ($8722 vs $8765 per beneficiary; RR, 1.00; 95% CI, 0.99-1.00). Beneficiaries residing in areas with the highest quintile of primary care clinician FTEs compared with those in the lowest quintile had lower mortality (5.19 vs 5.49 per 100 beneficiaries; RR, 0.95; 95% CI, 0.93-0.96), fewer ACSC hospitalizations (72.53 vs 79.48 per 1000 beneficiaries; RR, 0.91; 95% CI, 0.90-0.92), and higher overall Medicare spending ($8857 vs $8769 per beneficiary; RR, 1.01; 95% CI, 1.004-1.02). A higher level of primary care physician workforce, particularly with an FTE measure that may more accurately reflect ambulatory primary care, was generally associated with favorable patient outcomes.

Period changes of 7 bright RR Lyrae variables included in the BAV standard program.

NASA Astrophysics Data System (ADS)

Wunder, E.

1995-11-01

On the basis of 1578 times of maxima historical and present period changes of the RR Lyrae stars SW And, SW Aqr, AA Aql, X Ari, RS Boo, RR Cet and XZ Cyg are analysed. In tables the period jumps and the quadratic terms of the elements are quantified and timed; elements are given to describe the historical O-C-curves; instant elements are listed to support nowadays observations.

Encountering the Body at the Site of the Suicide: A Population-Based Survey in Sweden.

PubMed

Omerov, Pernilla; Pettersen, Rossana; Titelman, David; Nyberg, Tommy; Steineck, Gunnar; Dyregrov, Atle; Nyberg, Ullakarin

2017-02-01

Encountering the body of a child who died by suicide at the site of death is believed to be especially harmful for bereaved parents. We investigated the association between encountering the body at the site of the suicide and psychological distress in 666 suicide-bereaved parents. Parents who had encountered their child's body at the site of the suicide (n = 147) did not have a higher risk of nightmares (relative risk [RR] 0.95, 95% confidence interval [CI] 0.67-1.35), intrusive memories (RR 0.97, 95% CI 0.84-1.13), avoidance of thoughts (RR 0.97, 95% CI 0.74-1.27), avoidance of places or things (RR 0.91, 95% CI 0.66-1.25), anxiety (RR 0.93, 95% CI 0.64-1.33), or depression (RR 0.94, 95% CI 0.63-1.42) compared with parents who had not encountered the body (n = 512). Our results suggest that losing a child by suicide is sufficiently disastrous by itself to elicit posttraumatic responses or psychiatric morbidity whether or not the parent has encountered the deceased child at the site of death. © 2016 The American Association of Suicidology.

Immersion in water in labour and birth

PubMed Central

Cluett, Elizabeth R; Burns, Ethel

2014-01-01

Background Enthusiasts suggest that labouring in water and waterbirth increase maternal relaxation, reduce analgesia requirements and promote a midwifery model of care. Critics cite the risk of neonatal water inhalation and maternal/neonatal infection. Objectives To assess the evidence from randomised controlled trials about immersion in water during labour and waterbirth on maternal, fetal, neonatal and caregiver outcomes. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (30 June 2011) and reference lists of retrieved studies. Selection criteria Randomised controlled trials comparing immersion in any bath tub/pool with no immersion, or other non-pharmacological forms of pain management during labour and/or birth, in women during labour who were considered to be at low risk of complications, as defined by the researchers. Data collection and analysis We assessed trial eligibility and quality and extracted data independently. One review author entered data and the other checked for accuracy. Main results This review includes 12 trials (3243 women): eight related to just the first stage of labour: one to early versus late immersion in the first stage of labour; two to the first and second stages; and another to the second stage only. We identified no trials evaluating different baths/pools, or the management of third stage of labour. Results for the first stage of labour showed there was a significant reduction in the epidural/spinal/paracervical analgesia/anaesthesia rate amongst women allocated to water immersion compared to controls (478/1254 versus 529/1245; risk ratio (RR) 0.90; 95% confidence interval (CI) 0.82 to 0.99, six trials). There was also a reduction in duration of the first stage of labour (mean difference −32.4 minutes; 95% CI −58.7 to −6.13). There was no difference in assisted vaginal deliveries (RR 0.86; 95% CI 0.71 to 1.05, seven trials), caesarean sections (RR 1.21; 95% CI 0.87 to 1.68, eight trials), use of oxytocin infusion (RR 0.64; 95%CI 0.32 to 1.28,five trials), perineal trauma or maternal infection. There were no differences for Apgar score less than seven at five minutes (RR 1.58; 95% CI 0.63 to 3.93, five trials), neonatal unit admissions (RR 1.06; 95% CI 0.71 to 1.57, three trials), or neonatal infection rates (RR 2.00; 95% CI 0.50 to 7.94, five trials). Of the three trials that compared water immersion during the second stage with no immersion, one trial showed a significantly higher level of satisfaction with the birth experience (RR 0.24; 95% CI 0.07 to 0.80). A lack of data for some comparisons prevented robust conclusions. Further research is needed. Authors’ conclusions Evidence suggests that water immersion during the first stage of labour reduces the use of epidural/spinal analgesia and duration of the first stage of labour. There is limited information for other outcomes related to water use during the first and second stages of labour, due to intervention and outcome variability. There is no evidence of increased adverse effects to the fetus/neonate or woman from labouring in water or waterbirth. However, the studies are very variable and considerable heterogeneity was detected for some outcomes. Further research is needed. PMID:19370552

Drugs for preventing malaria in pregnant women.

PubMed

Garner, P; Gülmezoglu, A M

2006-10-18

Malaria contributes to maternal illness and anaemia in pregnancy, especially in first-time mothers, and can harm the mother and the baby. Drugs given routinely to prevent or mitigate the effects of malaria during pregnancy are often recommended. To assess drugs given to prevent malaria infection and its consequences in pregnant women living in malarial areas. This includes prophylaxis and intermittent preventive treatment (IPT). We searched the Cochrane Infectious Diseases Group Specialized Register (March 2006), CENTRAL (The Cochrane Library 2006, Issue 1), MEDLINE (1966 to March 2006), EMBASE (1974 to March 2006), LILACS (1982 to March 2006), and reference lists. We also contacted researchers working in the field. Randomized and quasi-randomized controlled trials comparing antimalarial drugs given regularly with no antimalarial drugs for preventing malaria in pregnant women living in malaria-endemic areas. Both authors extracted data and assessed methodological quality. Dichotomous variables were combined using relative risks (RR) and weighted mean differences (WMD) for mean values, both with 95% confidence intervals (CI). Sixteen trials (12,638 participants) met the inclusion criteria; two used adequate methods to conceal allocation. Antimalarials reduced antenatal parasitaemia when given to all pregnant women (RR 0.53, 95% CI 0.33 to 0.86; 328 participants, 2 trials), placental malaria (RR 0.34, 95% CI 0.26 to 0.45; 1236 participants, 3 trials), but no effect was detected with perinatal deaths (2890 participants, 4 trials). In women in their first or second pregnancy, antimalarial drugs reduced severe antenatal anaemia (RR 0.62, 95% CI 0.50 to 0.78; 2809 participants, 1 prophylaxis and 2 IPT trials), antenatal parasitaemia (RR 0.27, 95% CI 0.17 to 0.44, random-effects model; 2906 participants, 6 trials), and perinatal deaths (RR 0.73, 95% CI 0.53 to 0.99; 1986 participants, 2 prophylaxis and 1 IPT trial; mean birthweight was higher (WMD 126.70 g, 95% CI 88.64 to 164.75 g; 2648 participants, 8 trials), and low birthweight less frequent (RR 0.57, 95% CI 0.46 to 0.72; 2350 participants, 6 trials). Proguanil performed better than chloroquine in one trial of women of all parities in relation to maternal fever episodes. Sulfadoxine-pyrimethamine performed better than chloroquine in two trials of low-parity women. Chemoprophylaxis or IPT reduces antenatal parasite prevalence and placental malaria when given to women in all parity groups. They also have positive effects on birthweight and possibly on perinatal death in low-parity women.

VizieR Online Data Catalog: Gaia DR1 and OGLE variable stars (Udalski+, 2016)

NASA Astrophysics Data System (ADS)

Udalski, A.; Soszynski, I.; Skowron, D. M.; Skowron, J.; Pietrukowicz, P.; Mroz, P.; Poleski, R.; Szymanski, M. K.; Kozlowski, S.; Wyrzykowski, L.; Ulaczyk, K.; Pawlak, M.

2018-04-01

To assess the Gaia dataset of Cepheids and RR Lyr stars presented in the Gaia DR1 (Clementini et al., 2016A&A...595A.133C, Cat. I/337) we cross-identified the sample of 3194 variable stars presented on the final Gaia pipeline list (599 Cepheid and 2595 RR Lyr candidates) with the OGLE detected objects using RA/DEC coordinates provided within Gaia DR1. (4 data files).

Comparison of anthropometric measurements in children to predict metabolic syndrome in adolescence: analysis of prospective cohort data.

PubMed

Wicklow, B A; Becker, A; Chateau, D; Palmer, K; Kozyrskij, A; Sellers, E A C

2015-07-01

The optimal screening measures for obesity in children remain controversial. Our study aimed to determine the anthropometric measurement at age 10 years that most strongly predicts the incidence of cardio-metabolic risk factors at age 13 years. This was a prospective cohort study of a population-based cohort of 438 children followed between age 7 and 13 years of age. The main exposure variables were adiposity at age 10 years determined from body mass index (BMI) Z-score, waist circumference (WC) Z-score, waist-to-hip ratio and waist-to-height ratio. Outcome measures included systolic (SBP) and diastolic blood pressure (DBP), fasting high-density (HDL-c) and low-density lipoprotein cholesterol (LDL-c), triglycerides, insulin and glucose (homeostasis model of assessment, HOMA), and the presence of metabolic syndrome (MetS). WC Z-score at age 10 years was a stronger predictor of SBP (β 0.21, R(2) 0.38, P<0.001 vs β 0.30, R(2) 0.20, P<0.001) and HOMA (β 0.51, R(2) 0.25, P<0.001 vs 0.40, R(2) 0.19, P<0.001) at age 13 years compared with BMI Z-score. WC relative to height and hip was stronger predictors of cardio- metabolic risk than BMI Z-score or WC Z-score. The relative risk (RR) of incident MetS was greater for an elevated BMI Z-score than for an elevated WC (girls: RR 2.52, 95% confidence interval (CI): 1.46-4.34 vs RR 1.56, 95% CI 1.18-2.07) and (boys: RR 2.86, 95% CI 1.79-4.62 vs RR 2.09, 95% CI 1.59-2.77). WC was a better predictor of SBP and HOMA compared with BMI or WC expressed relative to height or hip circumference. BMI was associated with higher odds of MetS compared with WC. Thus, BMI and WC may each be clinically relevant markers of different cardio-metabolic risk factors, and important in informing obesity-related prevention and treatment strategies.

Cardiovascular Benefits of Wearing Particulate-Filtering Respirators: A Randomized Crossover Trial

PubMed Central

Shi, Jingjin; Lin, Zhijing; Chen, Renjie; Wang, Cuicui; Yang, Changyuan; Cai, Jing; Lin, Jingyu; Xu, Xiaohui; Ross, Jennifer A.; Zhao, Zhuohui; Kan, Haidong

2016-01-01

Background: Practical approaches to protect individuals from ambient particulate matter (PM) are urgently needed in developing countries. Evidence on the health benefits of wearing particulate-filtering respirators is limited. Objectives: We evaluated the short-term cardiovascular health effects of wearing respirators in China. Methods: A randomized crossover trial was performed in 24 healthy young adults in Shanghai, China in 2014. The subjects were randomized into two groups and wore particulate-filtering respirators for 48 hr alternating with a 3-week washout interval. Heart rate variability (HRV) and ambulatory blood pressure (BP) were continuously monitored during the 2nd 24 hr in each intervention. Circulating biomarkers were measured at the end of each intervention. Linear mixed-effect models were applied to evaluate the effects of wearing respirators on health outcomes. Results: During the intervention periods, the mean daily average concentration of PM with an aerodynamic diameter < 2.5 μm (PM2.5) was 74.2 μg/m3. Compared with the absence of respirators, wearing respirators was associated with a decrease of 2.7 mmHg [95% confidence interval (CI): 0.1, 5.2 mmHg] in systolic BP and increases of HRV parameters, including 12.5% (95% CI: 3.8%, 21.2%) in high frequency (HF) power, 10.9% (95% CI: 1.8%, 20.0%) in the root mean square of the successive differences, and 22.1% (95% CI: 3.6%, 40.7%) in the percentage of normal RR intervals with duration > 50 msec different from the previous normal RR interval (pNN50). The presence of respirators was also associated with a decrease of 7.8% (95% CI: 3.5%, 12.1%) in the ratio of low frequency (LF)/HF power. Conclusions: Short-term wearing of particulate-filtering respirators may produce cardiovascular benefits by improving autonomic nervous function and reducing BP. Citation: Shi J, Lin Z, Chen R, Wang C, Yang C, Cai J, Lin J, Xu X, Ross JA, Zhao Z, Kan H. 2017. Cardiovascular benefits of wearing particulate-filtering respirators: a randomized crossover trial. Environ Health Perspect 125:175–180; http://dx.doi.org/10.1289/EHP73 PMID:27562361

Risk of mortality associated with neonatal hypothermia in southern Nepal.

PubMed

Mullany, Luke C; Katz, Joanne; Khatry, Subarna K; LeClerq, Steven C; Darmstadt, Gary L; Tielsch, James M

2010-07-01

To quantify the neonatal mortality/hypothermia relationship and develop evidence-based cutoffs for global definitions of neonatal hypothermia. Cohort study. Field workers recorded neonatal axillary temperature at home and recorded vital status at 28 days. Rural Nepal. Twenty-three thousand two hundred forty infants in Sarlahi, Nepal. Hypothermia. Mortality risk was estimated using binomial regression models. Infants were classified using (1) World Health Organization (WHO) cutoffs for mild, moderate, and severe hypothermia; (2) quarter-degree intervals from 32.0 degrees C to 36.5 degrees C; and (3) continuous temperatures. Estimates were adjusted for age, ambient temperature, and other potential confounders. Mortality increased among mild (relative risk [RR], 1.70; 95% confidence interval [CI], 1.23-2.35]), moderate (RR, 4.66; 95% CI, 3.47-6.24]), and severe (RR, 23.36; 95% CI, 4.31-126.70]) hypothermia cases. Within the WHO's moderate classification, risk relative to normothermic infants ranged from 2 to 30 times. Adjusted mortality risk increased 80% (95% CI, 63%-100%) for each degree decrease, was strongly associated with temperatures below 35.0 degrees C (RR, 6.11; 95% CI, 3.98-9.38), and was substantially higher among preterm infants (RR, 12.02; 95% CI, 6.23-23.18]) compared with full-term infants (RR, 3.12; 95% CI, 1.75-5.57). Relative risk was highest in the first 7 days, but remained elevated through 28 days. A new hypothermia classification system should be considered by the WHO for global guidelines. We recommend that grade 1 be equivalent to the current mild category (36.0 degrees C), restricting and splitting the moderate category into grades 2 (35.0 degrees C-36.0 degrees C) and 3 (34.0 degrees C-35.0 degrees C), and expanding severe hypothermia to less than 34.0 degrees C (grade 4). Reducing hypothermia may dramatically decrease the global neonatal mortality burden.

Work-Related Biomechanical Exposure and Job Strain as Separate and Joint Predictors of Musculoskeletal Diseases: A 28-Year Prospective Follow-up Study.

PubMed

Prakash, K C; Neupane, Subas; Leino-Arjas, Päivi; von Bonsdorff, Mikaela B; Rantanen, Taina; von Bonsdorff, Monika E; Seitsamo, Jorma; Ilmarinen, Juhani; Nygård, Clas-Håkan

2017-12-01

We investigated how work-related biomechanical exposure and job strain in midlife separately and jointly predicted back and degenerative musculoskeletal diseases (MSDs). A total of 6,257 employees participated in the Finnish Longitudinal Study on Aging Municipal Employees (FLAME) in 1981 and were followed up for 28 years. Risk ratios and the relative excessive risk due to interaction and 95% confidence intervals were modeled for separate and joint prediction estimates, respectively. After adjustment for confounders, job strain predicted degenerative MSDs among women after 4 and 11 years of follow-up. After 11 years, both exposures predicted both types of MSDs among men. Joint exposure predicted both types of MSDs after 4 years among women (for back MSDs, risk ratio (RR) = 1.58, 95% confidence interval (CI): 1.15, 2.18; for degenerative MSDs, RR = 1.59, 95% CI: 1.21, 2.07) and men (for back MSDs, RR = 1.50, 95% CI: 1.05, 2.15; for degenerative MSDs, RR = 1.61, 95% CI: 1.16, 2.22) and both types of MSDs after 11 years (for back MSDs, RR = 1.72, 95% CI: 1.21, 2.43; for degenerative MSDs, RR = 1.68, 95% CI: 1.25, 2.46) among men only, but the relative excessive risk due to interaction was not significant throughout. However, after 28 years, the separate and joint exposures did not predict MSDs. Workplace interventions should be focused on reducing job strain along with biomechanical exposure for possible prevention of MSDs in working life and around the time of retirement, but there may be other pathways of onset of MSDs in old age. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Initiators and promoters for the occurrence of screen-detected breast cancer and the progression to clinically-detected interval breast cancer.

PubMed

Yen, Amy Ming-Fang; Wu, Wendy Yi-Ying; Tabar, Laszlo; Duffy, Stephen W; Smith, Robert A; Chen, Hsiu-Hsi

2017-03-01

The risk factors responsible for breast cancer have been well documented, but the roles of risk factors as initiators, causing the occurrence of screen-detected breast cancer, or promoters, responsible for the progression of the screen-detected to the clinically-detected breast cancer, have been scarcely evaluated. We used data from women in a cohort in Kopparberg (Dalarna), Sweden between 1977 and 2010. Conventional risk factors, breast density, and tumor-specific biomarkers are superimposed to the temporal course of the natural history of the disease. The results show that older age at first full-term pregnancy, dense breast, and a family history of breast cancer increased the risk of entering the preclinical screen-detectable phase of breast cancer by 23%, 41%, and 89%, respectively. Overweight/obesity (body mass index ≥25 kg/m 2 ) was a significant initiator (adjusted relative risk [aRR] 1.15; 95% confidence interval [CI], 0.99-1.33), but was inversely associated with the role of promoter (aRR 0.65; 95% CI, 0.51-0.82). Dense breast (aRR 1.46; 95% CI, 1.12-1.91), triple-negative (aRR 2.07; 95% CI, 1.37-3.15), and Ki-67 positivity (aRR 1.66; 95% CI, 1.19-2.30) were statistically significant promoters. When the molecular biomarkers were considered collectively as one classification, the basal-like subtype was the most influential subtype on promoters (aRR 4.24; 95% CI, 2.56-7.02) compared with the Luminal A subtype. We ascertained state-dependent covariates of initiators and promoters to classify the risk of the two-step progression of breast cancer. The results of the current study are useful for individually-tailored screening and personalized clinical surveillance of patients with breast cancer that was detected at an early stage. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Image-Subtraction Photometry of Variable Stars in the Field of the Globular Cluster NGC 6934

NASA Astrophysics Data System (ADS)

Kaluzny, J.; Olech, A.; Stanek, K. Z.

2001-03-01

We present CCD BVI photometry of 85 variable stars from the field of the globular cluster NGC 6934. The photometry was obtained with the image subtraction package ISIS. 35 variables are new identifications: 24 RRab stars, five RRc stars, two eclipsing binaries of W UMa-type, one SX Phe star, and three variables of other types. Both detected contact binaries are foreground stars. The SX Phe variable belongs most likely to the group of cluster blue stragglers. Large number of newly found RR Lyr variables in this cluster, as well as in other clusters recently observed by us, indicates that total RR Lyr population identified up to date in nearby galactic globular clusters is significantly (>30%) incomplete. Fourier decomposition of the light curves of RR Lyr variables was used to estimate the basic properties of these stars. From the analysis of RRc variables we obtain a mean mass of M=0.63 Msolar, luminosity logL/Lsolar=1.72, effective temperature Teff=7300 and helium abundance Y=0.27. The mean values of the absolute magnitude, metallicity (on Zinn's scale) and effective temperature for RRab variables are MV=0.81, [Fe/H]=-1.53 and Teff=6450, respectively. From the B-V color at minimum light of the RRab variables we obtained the color excess to NGC 6934 equal to E(B-V)=0.09+/-0.01. Different calibrations of absolute magnitudes of RRab and RRc available in literature were used to estimate apparent distance modulus of the cluster: (m-M)V=16.09+/-0.06. We note a likely error in the zero point of the HST-based V-band photometry of NGC 6934 recently presented by Piotto et al. Among analyzed sample of RR Lyr stars we have detected a short period and low amplitude variable which possibly belongs to the group of second overtone pulsators (RRe subtype variables). The BVI photometry of all variables is available electronically via anonymous ftp. The complete set of the CCD frames is available upon request. Based on observations obtained with the 1.2 m Telescope at the F. L. Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics.

Association of antenatal depression with adverse consequences for the mother and newborn in rural Ghana: findings from the DON population-based cohort study.

PubMed

Weobong, Benedict; ten Asbroek, Augustinus H A; Soremekun, Seyi; Manu, Alexander A; Owusu-Agyei, Seth; Prince, Martin; Kirkwood, Betty R

2014-01-01

Whilst there is compelling evidence of an almost 2-fold increased risk of still births, and suggestive evidence of increased mortality among offspring of mothers with psychotic disorders, only three studies have addressed the role of antenatal depression (AND) on survival of the baby. We examined these associations in a large cohort of pregnant women in Ghana. A Cohort study nested within 4-weekly surveillance of all women of reproductive age to identify pregnancies and collect data on births and deaths in the Kintampo Health Research Centre study area of Ghana. Women were screened for AND using the Patient Health Questionnaire (PHQ-9) to ascertain DSM-IV major or minor depression. Outcomes were adverse birth outcomes, maternal/infant morbidity, and uptake of key newborn care practices, examined using logistic regression; effect sizes reported as relative risks with 95% confidence intervals. 20679 (89.6%) pregnant women completed the PHQ-9. The prevalence of AND was 9.9% (n = 2032) (95% confidence interval 9.4%-10.2%). AND was associated with: prolonged labour (RR 1.25, 95% CI 1.02-1.53); peripartum complications (RR 1.11, 95% CI 1.07-1.15); postpartum complications (RR 1.27, 96% CI 1.21-1.34); non-vaginal delivery (RR 1.19, 95% CI 1.02-1.40); newborn illness (RR 1.52, 95% CI 1.16-1.99); and bed net use during pregnancy (RR 0.93, 95% CI 0.89-0.98), but not neonatal deaths, still births, low birth weight, immediate breast feeding initiation, or exclusive breastfeeding. AND was marginally associated with preterm births (RR 1.32, 95% CI 0.98-1.76). This paper has contributed important evidence on the role of antenatal depression as a potential contributor to maternal and infant morbidity. Non-pharmacological treatments anchored on primary care delivery structures are recommended as an immediate step. We further recommend that trials are designed to assess if treating antenatal depression in conjunction with improving the quality of obstetric care results in improved maternal and newborn outcomes.

The soundtrack of RR Lyrae in omega Cen at high-frequency.

NASA Astrophysics Data System (ADS)

Calamida, A.; Randall, S. K.; Monelli, M.; Bono, G.; Buonanno, R.; Strampelli, G.; Catelan, M.; Van Grootel, V.; Alonso, M. L.; Stetson, P. B.; Stellingwerf, R. F.

We present preliminary Sloan u',g'-band light curves for a sample of known RR Lyrae variables in the Galactic globular cluster omega Cen. Results are based on the partial reduction of multi-band time series photometric data collected during six consecutive nights with the visitor instrument ULTRACAM mounted on the New Technology Telescope (La Silla, ESO). This facility allowed us to simultaneously observe in three different bands (Sloan u',g',r') a field of view of ˜ 6×6 arcminutes. The telescope and the good seeing conditions allowed us to sample the light curves every 15 seconds. We ended up with a data set of ˜ 6,000 images per night per filter, for a total of more than 200,000 images of the selected field. This data set allowed us to detect different kind of variables, such as RR-Lyraes, SX Phoenicis, eclipsing binaries, semi-regulars. More importantly, we were able for the first time to sample at high-frequency cluster RR Lyraes in the u',g'-band and to show in detail the pulsation phases across the dip located along the rising branch of RR-Lyraes. Based on data collected with ULTRACAM@NTT (La Silla, ESO, PID: 087.D-0216)

Determinants of long-lasting insecticidal net use in Burkina Faso after a mass distribution in the Diébougou health district.

PubMed

Tinoaga Ouédraogo, L; Ouédraogo, I; Yaméogo, A; Ouédraogo, V

2013-04-01

In 2009, a mass distribution of long-lasting insecticidal nets (LLINs) was conducted in an experimental site of the Diébougou health district. Carried out 1year after the distribution, this study aimed to determine the presence of LLINs in households, to determine the LLIN use rate, and thirdly, to identify key factors associated with LLIN use in households. We conducted a cross-sectional descriptive and analytical study, which covered the entire Diébougou health district. The study population consisted of households in the district. The statistical unit was the household head, or if absent his designated representative. For the selection of households to be studied, we considered the health centers and their geographic accessibility. We thus defined three zones: an area within 5 km of health centers, the area between 5 and 10 km away, and the area beyond 10 km. In each area, we randomly selected 20 households, totaling 60 households in the area of each health center, giving a sample of 840 households to be surveyed. We selected 60 households per health center in accordance with the time and financial resources allocated to data collection. The data were analyzed using the Epi Info 3.5.1 software package. The Chi square test was used to investigate the association between the dependent and independent variables with statistical significance set at P<0.05. When an association was demonstrated, the relative risk (RR) was calculated with the 95% confidence interval. A total of 822 households (97.8%) were surveyed, households inhabited by 6379 people including 1175 (11.4%) children under 5 years of age and 158 (2.5%) pregnant women. The overall use of LLINs was 76.5%. This rate was 81.7% in children under 5 years and 57.6% among pregnant women. Factors influencing the use of LLINs were the implementation of a communication plan by health actors (RR=2.42 [2.03-2.83]), the social position of the household head (RR=1.62 [1.43-1.83]), the marital status of the household head (RR=1.41 [1.33-1.49]), the number of persons per room (RR=1.39 [1.08-1.78]), the religion of household head (RR=1.21 [1.15-1.27]), the level of education of the household head (RR=1.15 [1.06-1.24]), and the number of IECs (information, education, communication) sessions followed by the household (RR=1.14 [1.08-1.20]). The results of this study provide guidance on measures to ensure the success of the mass distribution of LLINs to the entire country. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Peculiar double-periodic pulsation in RR Lyrae stars of the OGLE collection - II. Short-period stars with a dominant radial fundamental mode

NASA Astrophysics Data System (ADS)

Prudil, Z.; Smolec, R.; Skarka, M.; Netzel, H.

2017-03-01

We report the discovery of a new group of double-periodic stars in the OGLE Galactic bulge photometry. In 38 stars identified as fundamental-mode RR Lyrae and four classified as first-overtone RR Lyrae, we detected an additional shorter periodicity. The periods of the dominant variability in the newly discovered group are 0.28 < PD < 0.41 d. Period ratios (0.68-0.72) are smaller than the period ratios of the Galactic bulge RRd stars. The typical amplitude ratio (of the additional to the dominant periodicity) is 20 per cent for the stars identified as fundamental-mode RR Lyrae and 50 per cent for stars classified as first-overtone RR Lyrae. 10 stars from our sample exhibit equidistant peaks in the frequency spectrum, which suggests the Blazhko-type modulation of the main pulsation frequency and/or additional periodicity. The Fourier coefficients R21 and R31 are some of the lowest among fundamental-mode RR Lyrae stars, but among the highest for the first-overtone pulsators. For the phase Fourier coefficients φ21 and φ31, our stars lie between RRab and RRc stars. The stars discussed were compared with radial linear pulsation models. Their position in the Petersen diagram cannot be reproduced by assuming that two radial modes are excited and their physical parameters are like those characteristic of RR Lyrae stars. The non-radial-mode scenario also faces difficulties. We conclude that the dominant variability is most likely due to pulsation in the radial fundamental mode, which applies to stars classified as first-overtone mode pulsators. At this point, we cannot explain the nature of the additional periodicity. Even more, the classification of the stars as RR Lyrae should be treated as tentative.

Effects of fluoridated drinking water on bone mass and fractures: the study of osteoporotic fractures.

PubMed

Cauley, J A; Murphy, P A; Riley, T J; Buhari, A M

1995-07-01

To determine if optimal fluoridation of public water supplies influences bone mass and fractures, we studied 2076 non-black women, all aged > or = 65 years recruited into the Study of Osteoporotic Fractures at the Pittsburgh clinic. Information on fluoride exposure was limited to community water supplies. The variable used in the analysis was years of exposure to fluoridated water in community drinking water supplies. Bone mineral density (BMD) was measured at the spine and hip using dual energy X-ray absorptiometry and at the midpoint and ultradistal radius and calcaneus using single photon absorptiometry. Prevalent and incident vertebral fractures were determined by morphometry. Incident nonspine fractures were ascertained every 4 months and confirmed by radiographic report. Exposure to residential fluoridated water had no effect on bone mass. Women exposed to fluoride for > 20 years had similar axial and appendicular bone mass to women not exposed or women exposed for < or = 20 years. There was some suggestion that women exposed to fluoride for > 20 years had a lower relative risk of nonspine fractures (relative risk, RR, = 0.73; 95% confidence interval [CI] 0.48-1.12), osteoporotic fractures, RR = 0.74 (CI 0.46-1.19), and hip fractures, RR = 0.44 (CI 0.10-1.86), compared with women not exposed, but none of these relative risks was statistically significant. There was no association with wrist or spinal fractures. Our results do not support the findings from recent ecological studies which showed an increased risk of hip fracture among individuals exposed to fluoridated public water.

Impact of delay in diagnosis on survival to head and neck carcinomas: a systematic review with meta-analysis.

PubMed

Seoane, J; Takkouche, B; Varela-Centelles, P; Tomás, I; Seoane-Romero, J M

2012-04-01

To address the contradictory information on the role of delay in diagnosis on head and neck cancer survival. Systematic review and meta-analysis. Search on MEDLINE (1966 to March 2011), EMBASE (1980 to March 2011) and ISI proceedings (from inception to March 2011). The terms used were ('Head and neck cancers') AND ('delay'OR'prognostic'OR'survival') both in MeSH terms and free-text words. The reference lists of the retrieved articles were also revised manually to identify other potentially relevant papers. All searches were independently undertaken by two clinicians and one epidemiologist, and the results merged. Primary and specialised care levels. Meta-analysis of data from papers on the subject published from 1966 to 2011. Survival. After search in Medline and other databases, we computed pooled relative risks (RR) and 95% confidence interval (95%CI) from the 10 studies retrieved. The estimate of the relative risk of mortality related to any diagnostic delay (either patient or professional delay) was 1.34 (95%CI 1.12-1.61). Referral delay was associated with a three-fold increase in mortality. Total delay was marginally related to mortality (RR: 1.04, 95%CI: 1.01-1.07). By anatomic location, pharynx cancer shows the highest association (RR: 1.68, 95%CI: 1.22-2.31). Diagnostic delay is a moderate risk factor of mortality from head and neck cancer. However, part of the effect observed may be due to residual confounding (confounding from unknown variables that are not eliminated by adjustment). © 2012 Blackwell Publishing Ltd.

Standard versus Rotation Technique for Insertion of Supraglottic Airway Devices: Systematic Review and Meta-Analysis

PubMed Central

Park, Jin Ha; Lee, Jong Seok; Nam, Sang Beom; Ju, Jin Wu

2016-01-01

Purpose Supraglottic airway devices have been widely utilized as an alternative to tracheal intubation in various clinical situations. The rotation technique has been proposed to improve the insertion success rate of supraglottic airways. However, the clinical efficacy of this technique remains uncertain as previous results have been inconsistent, depending on the variable evaluated. Materials and Methods We systematically searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials in April 2015 for randomized controlled trials that compared the rotation and standard techniques for inserting supraglottic airways. Results Thirteen randomized controlled trials (1505 patients, 753 with the rotation technique) were included. The success rate at the first attempt was significantly higher with the rotation technique than with the standard technique [relative risk (RR): 1.13; 95% confidence interval (CI): 1.05 to 1.23; p=0.002]. The rotation technique provided significantly higher overall success rates (RR: 1.06; 95% CI: 1.04 to 1.09; p<0.001). Device insertion was completed faster with the rotation technique (mean difference: -4.6 seconds; 95% CI: -7.37 to -1.74; p=0.002). The incidence of blood staining on the removed device (RR: 0.36; 95% CI: 0.27 to 0.47; p<0.001) was significantly lower with the rotation technique. Conclusion The rotation technique provided higher first-attempt and overall success rates, faster insertion, and a lower incidence of blood on the removed device, reflecting less mucosal trauma. Thus, it may be considered as an alternative to the standard technique when predicting or encountering difficulty in inserting supraglottic airways. PMID:27189296

Cardiovascular hemodynamic effects of Red Bull® Energy Drink during prolonged, simulated, monotonous driving.

PubMed

Yamakoshi, Takehiro; Matsumura, Kenta; Hanaki, Shota; Rolfe, Peter

2013-12-01

The purpose of this study was to investigate the cardiovascular hemodynamic effects of Red Bull® Energy Drink during prolonged, simulated, monotonous driving. This was a double-blind, within-subjects-design, crossover study. Twelve healthy volunteers (21.7 ± 0.8 years old) experienced each of three conditions at various times: 1) consumption of Red Bull® Energy Drink; 2) consumption of placebo-controlled drink; and 3) no test drink. All subjects undertook 90-min periods of simulated monotonous driving, during which physiological measurements were made. The variables recorded were cardiovascular indices, i.e., mean blood pressure (MBP), cardiac output (CO), electrocardiogram RR interval (RR), total peripheral-vascular resistance (TPR: = MBP/CO), and normalized pulse volume (NPV). Additional parameters were the standard deviation of lateral position, i.e., the weaving of the car, and subjective rating of sleepiness. CO, RR, and TPR during the monotonous task were significantly different in those consuming the energy drink as compared with those receiving the placebo and as compared with no drink values. The energy drink elicited a cardiac-dominant reaction pattern, while the other conditions demonstrated the vascular-dominant reaction pattern typically observed in monotonous driving tasks. The observed differences indicate the cardiovascular system being more aroused with the energy drink. The effects of Red Bull® Energy Drink were reflected in cardiovascular hemodynamic phenomena especially to the heart function, and we conclude that consumption of this drink before long-distance driving in non-sleepy drivers could facilitate more physiologically active, and possibly safer, driving.

Effects of Weather and Heliophysical Conditions on Emergency Ambulance Calls for Elevated Arterial Blood Pressure

PubMed Central

Vencloviene, Jone; Babarskiene, Ruta M.; Dobozinskas, Paulius; Sakalyte, Gintare; Lopatiene, Kristina; Mikelionis, Nerijus

2015-01-01

We hypothesized that weather and space weather conditions were associated with the exacerbation of essential hypertension. The study was conducted during 2009–2010 in the city of Kaunas, Lithuania. We analyzed 13,475 cards from emergency ambulance calls (EACs), in which the conditions for the emergency calls were made coded I.10–I.15. The Kaunas Weather Station provided daily records of air temperature (T), wind speed (WS), relative humidity, and barometric pressure (BP). We evaluated the associations between daily weather variables and daily number of EACs by applying a multivariate Poisson regression. Unfavorable heliophysical conditions (two days after the active-stormy geomagnetic field or the days with solar WS > 600 km/s) increased the daily number of elevated arterial blood pressure (EABP) by 12% (RR = 1.12; 95% confidence interval (CI) 1.04–1.21); and WS ≥ 3.5 knots during days of T < 1.5 °C and T ≥ 12.5 °C by 8% (RR = 1.08; CI 1.04–1.12). An increase of T by 10 °C and an elevation of BP two days after by 10 hPa were associated with a decrease in RR by 3%. An additional effect of T was detected during days of T ≥ 17.5 °C only in females. Women and patients with grade III arterial hypertension at the time of the ambulance call were more sensitive to weather conditions. These results may help in the understanding of the population’s sensitivity to different weather conditions. PMID:25734792

Cortisol and progestin release, heart rate and heart rate variability in the pregnant and postpartum mare, fetus and newborn foal.

PubMed

Nagel, C; Erber, R; Bergmaier, C; Wulf, M; Aurich, J; Möstl, E; Aurich, C

2012-09-01

The mechanisms leading to parturition in the horse in many aspects differ from those in other species. Pregnancy is maintained not by progesterone but by 5α-pregnanes and the progestin precursor pregnenolone originates from the fetus. As parturition approaches, the fetal adrenal switches from pregnenolone to cortisol synthesis but it is not known whether cortisol crosses the placenta. We hypothesized that in parallel to fetal cortisol release, cortisol in the maternal circulation increases before foaling and this increase can be determined in both saliva and plasma. In addition, maternal, fetal and neonatal heart rate and heart rate variability were measured. In 25 pregnant mares, saliva for cortisol analysis was collected 4 times daily from 15 days before to 5 days after foaling. In 13 mares, in addition, fetomaternal electrocardiogram (ECG) recordings were made and blood samples for progestin and cortisol analysis were collected once daily. Heart rate (HR) was recorded until 5 days after foaling. The heart rate variability (HRV) variables standard deviation of the beat-to-beat (RR) interval (SDRR) and root mean square of successive RR differences (RMSSD) were calculated. From Days 15 to 4 before parturition, progestin concentration increased (peak 267 ± 42 ng/mL) and decreased thereafter (P < 0.05, day of foaling 113 ± 18 ng/mL). A prepartum increase in maternal cortisol concentrations was evident in blood (P < 0.05) and saliva (P < 0.05) and paralleled the decrease in progestin concentrations. In mares, HR remained constant during the last days of pregnancy but decreased within one day after parturition (P < 0.05) while maternal HRV did not change. In the fetus and neonate, HR increased from before to after birth (P < 0.05) indicating increasing demands on the cardiovascular system with adaptation to extrauterine life. Copyright © 2012 Elsevier Inc. All rights reserved.

Socio-economic differences in HIV/AIDS mortality in South Africa.

PubMed

Probst, Charlotte; Parry, Charles D H; Rehm, Jürgen

2016-07-01

To quantify socio-economic differences in the risk of HIV/AIDS mortality in South Africa for different measures of socio-economic status. Systematic literature search in Web of Knowledge and PubMed. Measures of relative risk (RR) were pooled separately for education, income, assets score and employment status as measures of socio-economic status, using inverse-variance weighted DerSimonian-Laird random effects meta-analyses. Ten studies were eligible for inclusion comprising over 175 000 participants and 6700 deaths. For income (RR 1.55, 95% confidence interval (CI) 1.15-2.09), assets score (RR 1.63, 95% CI 1.12-2.36) and employment status (RR 1.52, 95% CI 1.21-1.92), persons of low socio-economic status had an over 50% higher risk of dying from HIV/AIDS. The RR of 1.10 for education was not significant (95% CI 0.74-1.65). Future research should identify effective strategies to reduce HIV/AIDS mortality and alleviate the consequences of HIV/AIDS deaths, particularly for poorer households. © 2016 John Wiley & Sons Ltd.

Kubios HRV--heart rate variability analysis software.

PubMed

Tarvainen, Mika P; Niskanen, Juha-Pekka; Lipponen, Jukka A; Ranta-Aho, Perttu O; Karjalainen, Pasi A

2014-01-01

Kubios HRV is an advanced and easy to use software for heart rate variability (HRV) analysis. The software supports several input data formats for electrocardiogram (ECG) data and beat-to-beat RR interval data. It includes an adaptive QRS detection algorithm and tools for artifact correction, trend removal and analysis sample selection. The software computes all the commonly used time-domain and frequency-domain HRV parameters and several nonlinear parameters. There are several adjustable analysis settings through which the analysis methods can be optimized for different data. The ECG derived respiratory frequency is also computed, which is important for reliable interpretation of the analysis results. The analysis results can be saved as an ASCII text file (easy to import into MS Excel or SPSS), Matlab MAT-file, or as a PDF report. The software is easy to use through its compact graphical user interface. The software is available free of charge for Windows and Linux operating systems at http://kubios.uef.fi. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Ectopic beats in approximate entropy and sample entropy-based HRV assessment

NASA Astrophysics Data System (ADS)

Singh, Butta; Singh, Dilbag; Jaryal, A. K.; Deepak, K. K.

2012-05-01

Approximate entropy (ApEn) and sample entropy (SampEn) are the promising techniques for extracting complex characteristics of cardiovascular variability. Ectopic beats, originating from other than the normal site, are the artefacts contributing a serious limitation to heart rate variability (HRV) analysis. The approaches like deletion and interpolation are currently in use to eliminate the bias produced by ectopic beats. In this study, normal R-R interval time series of 10 healthy and 10 acute myocardial infarction (AMI) patients were analysed by inserting artificial ectopic beats. Then the effects of ectopic beats editing by deletion, degree-zero and degree-one interpolation on ApEn and SampEn have been assessed. Ectopic beats addition (even 2%) led to reduced complexity, resulting in decreased ApEn and SampEn of both healthy and AMI patient data. This reduction has been found to be dependent on level of ectopic beats. Editing of ectopic beats by interpolation degree-one method is found to be superior to other methods.

Whole-Body Vibration Training Improves Heart Rate Variability and Body Fat Percentage in Obese Hispanic Postmenopausal Women.

PubMed

Severino, Gregory; Sanchez-Gonzalez, Marcos; Walters-Edwards, Michelle; Nordvall, Michael; Chernykh, Oksana; Adames, Jason; Wong, Alexei

2017-07-01

The present study examined the effects of a 6-week whole-body vibration training (WBVT) regimen on heart rate variability (HRV) and body composition in obese Hispanic postmenopausal women. Participants were randomly assigned to either WBVT (n = 13) or a nonexercising control group (n = 14). HRV and body composition were measured before and after 6 weeks. There was a significant group by time interaction (P < .05) for heart rate, sympathovagal balance, and body fat percentage (BF%) such that all significantly decreased (P < .05); and R-R intervals significantly increased (P < .05) following WBVT compared to no changes after control. The changes in sympathovagal balance were correlated with changes in BF% (r = .63, P < .05). Our findings indicate that WBVT improves HRV and BF% in obese Hispanic postmenopausal women. The improvement in BF% partially explained the decrease in sympathovagal balance. Since obese and older individuals are at increased risk of developing cardiovascular diseases, they could potentially benefit from WBVT.

Meta-analysis: eating frequency and risk of colorectal cancer.

PubMed

Liu, Yanqiong; Tang, Weizhong; Zhai, Limin; Yang, Shi; Wu, Junrong; Xie, Li; Wang, Jian; Deng, Yan; Qin, Xue; Li, Shan

2014-04-01

Eating frequency has been implicated in the risk of colorectal cancer (CRC) in several epidemiological studies with contradictory and inconclusive findings. We performed a meta-analysis to evaluate their relationship. The pooled relative risk (RR) with 95% confidence interval (CI) was calculated to estimate the effects. A total of 15 eligible studies with 141,431 subjects and 11,248 cases were retrieved after a comprehensive search of the PubMed, Cochrane Library, and Web of Science databases up to October 2013. The overall meta-analysis revealed no strong significant association between eating frequency and risk of CRC in different eating occasion categories (1 meal/day): RR = 1.01, 95% CI 0.94-1.09, P = 0.709; 3 vs. <3 daily meals: RR = 1.17, 95% CI 0.93-1.46; 4 vs. <3 daily meals: RR = 1.13, 95% CI 0.92-1.38; ≥ 5 vs. <3 daily meals: RR = 0.95, 95% CI 0.61-1.47; 4 vs. ≤ 3 daily meals: RR = 1.18, 95% CI 0.92-1.51; and 1-2 vs. 3 or 4 daily meals: RR = 0.82, 95% CI 0.63-1.06). However, modest evidence of an increased risk of CRC in case-control studies (RR = 1.30; 95% CI, 1.11-1.52) and ≥ 5 vs. ≤ 3 meals group (RR = 1.30; 95% CI, 1.11-1.52) was observed. Our meta-analysis results do not support the hypothesis that eating frequency strongly reduced or increased the risk of CRC. Clinical randomized trials are required to evaluate this relationship further.

Relative risk of listeriosis in Foodborne Diseases Active Surveillance Network (FoodNet) sites according to age, pregnancy, and ethnicity.

PubMed

Pouillot, Régis; Hoelzer, Karin; Jackson, Kelly A; Henao, Olga L; Silk, Benjamin J

2012-06-01

Quantitative estimates of the relative risk (RR) of listeriosis among higher-risk populations and a nuanced understanding of the age-specific risks are crucial for risk assessments, targeted interventions, and policy decisions. The RR of invasive listeriosis was evaluated by age, pregnancy status, and ethnicity using 2004-2009 data from the Foodborne Diseases Active Surveillance Network (FoodNet). Nonparametric logistic regression was used to characterize changes in risk with age and ethnicity. Adjusted RRs and 95% confidence intervals (CIs) were evaluated using negative binomial generalized linear models. Among non-pregnancy-associated cases, listeriosis incidence rates increased gradually with age (45-59 years: RR, 4.7; 95% CI, 3.3-6.8; >85 years: RR, 53.8; 95% CI, 37.3-78.9; reference: 15-44 years). The RR was significantly higher for Hispanics than for non-Hispanics (RR, 1.8; 95% CI, 1.3-2.5). Among women of reproductive age (15-44 years), pregnant women had a markedly higher listeriosis risk (RR, 114.6; 95% CI, 68.9-205.1) than nonpregnant women. The RR was higher for Hispanic than non-Hispanic women, regardless of pregnancy status, and this increased during the study period (2004-2006: RR, 1.9; 95% CI, 1.0-3.3; 2007-2009: RR, 4.8; 95% CI, 3.1-7.1). This study quantifies the increases in risk of listeriosis among older persons, pregnant women, and Hispanics in the United States. Additional research is needed to better describe the independent effects of age on risk while accounting for underlying conditions. These estimates are needed both to optimize risk assessment models and to inform targeted interventions and policy decisions.

Failure to Redose Antibiotic Prophylaxis in Long Surgery Increases Risk of Surgical Site Infection.

PubMed

Kasatpibal, Nongyao; Whitney, Joanne D; Dellinger, E Patchen; Nair, Bala G; Pike, Kenneth C

Antibiotic prophylaxis is a key component of the prevention of surgical site infection (SSI). Failure to manage antibiotic prophylaxis effectively may increase the risk of SSI. This study aimed to examine the effects of antibiotic prophylaxis on SSI risk. A retrospective cohort study was conducted among patients having general surgery between May 2012 and June 2015 at the University of Washington Medical Center. Peri-operative data extracted from hospital databases included patient and operation characteristics, intra-operative medication and fluid administration, and survival outcome. The effects of antibiotic prophylaxis and potential factors on SSI risk were estimated using multiple logistic regression and were expressed as risk ratios (RRs). A total of 4,078 patients were eligible for analysis. Of these, 180 had an SSI. Mortality rates within and after 30 days were 0.8% and 0.3%, respectively. Improper antibiotic redosing increased the risk of SSI (RR 4.61; 95% confidence interval [CI] 1.33-15.91). Other risk factors were in-patient status (RR 4.05; 95% CI 1.69-9.66), smoking (RR 1.63; 95% CI 1.03-2.55), emergency surgery (RR 1.97; 95% CI 1.26-3.08), colectomy (RR 3.31; 95% CI 1.19-9.23), pancreatectomy (RR 4.52; 95% CI 1.53-13.39), proctectomy (RR 5.02; 95% CI 1.72-14.67), small bowel surgery (RR 6.16; 95% CI 2.13-17.79), intra-operative blood transfusion >500 mL (RR 2.76; 95% CI 1.45-5.26), and multiple procedures (RR 1.40; 95% CI 1.01-1.95). These data demonstrate that failure to redose prophylactic antibiotic during long operations increases the risk of SSI. Strengthening a collaborative surgical quality improvement program may help to eradicate this risk.

Drinking water chlorination and cancer-a historical cohort study in Finland.

PubMed

Koivusalo, M; Pukkala, E; Vartiainen, T; Jaakkola, J J; Hakulinen, T

1997-03-01

Chlorination of water rich in organic material is known to produce a complex mixture of organochlorine compounds, including mutagenic and carcinogenic substances. A historical cohort study of 621,431 persons living in 56 towns in Finland was conducted in order to assess the relation between historical exposure to drinking water mutagenicity and cancer. Exposure to quantity of mutagenicity was calculated on the basis of historical information of raw water quality and water treatment practices using an empirical equation relating mutagenicity and raw water pH, KMnO4 value and chlorine dose. Cancer cases were derived from the population-based Finnish Cancer Registry and follow-up time in the study started in 1970. Age, gender, time period, social class, and urban residence were taken into account in Poisson regression analysis of the observed numbers of cases using expected numbers of cases standardized for age and gender as a basis. Excess risks were calculated using a continuous variable for mutagenicity for 3,000 net rev/l exposure representing an average exposure in a town using chlorinated surface water. After adjustment for confounding, a statistically significant excess risk was observed for women in cancers of the bladder (relative risk [RR] = 1.48, 95 percent confidence interval [CI] = 1.01-2.18), rectum (RR = 1.38, CI = 1.03-1.85), esophagus (RR = 1.90, CI = 1.02-3.52), and breast (RR = 1.11, CI = 1.01-1.22). These results support the magnitude of excess risks for rectal and bladder cancers found in earlier epidemiologic studies on chlorination by-products and give additional information on exposure-response concerning the mutagenic compounds. Nevertheless, due to the public health importance of water chlorination, uncertainty related to the magnitude of observed risks, and the fact that excess risks were observed only for women, the results of the study should be interpreted with caution.

Comparison of cutting and pencil-point spinal needle in spinal anesthesia regarding postdural puncture headache

PubMed Central

Xu, Hong; Liu, Yang; Song, WenYe; Kan, ShunLi; Liu, FeiFei; Zhang, Di; Ning, GuangZhi; Feng, ShiQing

2017-01-01

Abstract Background: Postdural puncture headache (PDPH), mainly resulting from the loss of cerebral spinal fluid (CSF), is a well-known iatrogenic complication of spinal anesthesia and diagnostic lumbar puncture. Spinal needles have been modified to minimize complications. Modifiable risk factors of PDPH mainly included needle size and needle shape. However, whether the incidence of PDPH is significantly different between cutting-point and pencil-point needles was controversial. Then we did a meta-analysis to assess the incidence of PDPH of cutting spinal needle and pencil-point spinal needle. Methods: We included all randomly designed trials, assessing the clinical outcomes in patients given elective spinal anesthesia or diagnostic lumbar puncture with either cutting or pencil-point spinal needle as eligible studies. All selected studies and the risk of bias of them were assessed by 2 investigators. Clinical outcomes including success rates, frequency of PDPH, reported severe PDPH, and the use of epidural blood patch (EBP) were recorded as primary results. Results were evaluated using risk ratio (RR) with 95% confidence interval (CI) for dichotomous variables. Rev Man software (version 5.3) was used to analyze all appropriate data. Results: Twenty-five randomized controlled trials (RCTs) were included in our study. The analysis result revealed that pencil-point spinal needle would result in lower rate of PDPH (RR 2.50; 95% CI [1.96, 3.19]; P < 0.00001) and severe PDPH (RR 3.27; 95% CI [2.15, 4.96]; P < 0.00001). Furthermore, EBP was less used in pencil-point spine needle group (RR 3.69; 95% CI [1.96, 6.95]; P < 0.0001). Conclusions: Current evidences suggest that pencil-point spinal needle was significantly superior compared with cutting spinal needle regarding the frequency of PDPH, PDPH severity, and the use of EBP. In view of this, we recommend the use of pencil-point spinal needle in spinal anesthesia and lumbar puncture. PMID:28383416

A population-based study of the associations of stroke occurrence with weather parameters in Siberia, Russia (1982-92).

PubMed

Feigin, V L; Nikitin, Y P; Bots, M L; Vinogradova, T E; Grobbee, D E

2000-03-01

Previous studies have established a seasonal variation in stroke occurrence, but none have assessed the influence of inclement weather conditions on stroke incidence in a general population of Russia. We performed a stroke population-based study in the Oktiabrsky District of Novosibirsk, Siberia, Russia. Included in the analysis were 1929 patients with their first occurrence of ischemic stroke (IS), 215 patients with their first occurrence of intracerebral hemorrhage (ICH) and 64 patients with their first occurrence of subarachnoid hemorrhage (SAH): all patients were aged between 25 and 74 years. The cumulative daily occurrence of total strokes and stroke subtypes was evaluated in relation to aggregated daily mean values of ambient temperature, relative humidity and air pressure by means of Poisson regression analysis to estimate the rate ratio (RR) with corresponding confidence interval (CI) and to identify the weather parameters of most importance. In a multivariate analysis, with adjustment for the effects of season, solar and geomagnetic activity, and age of the patients, low ambient temperature (RR 1.32; 95% CI 1.05-1.66) and mean value of air pressure (RR 0.986; 95% CI 0.972-0.999) were important predictors of IS occurrence, while mild ambient temperature (RR 1.52; 95% CI 1. 04-2.22) was an important predictor of ICH occurrence. No relationship between SAH occurrence and any one of the weather parameters studied was revealed. There was no interaction between any meteorological variables that was statistically significant. Inclement weather conditions are associated with the occurrence of IS and ICH in Siberia, Russia. Among the meteorological parameters studied, low ambient temperature and mean air pressure are the most important predictors of IS occurrence, whereas the occurrence of ICH is associated with mild ambient temperature. There is no association between any one of the weather parameters studied and the occurrence of SAH.

Patient- and physician-related risk factors for hyperkalaemia in potassium-increasing drug-drug interactions.

PubMed

Eschmann, Emmanuel; Beeler, Patrick E; Kaplan, Vladimir; Schneemann, Markus; Zünd, Gregor; Blaser, Jürg

2014-02-01

Hyperkalaemia due to potassium-increasing drug-drug interactions (DDIs) is a clinically important adverse drug event. The purpose of this study was to identify patient- and physician-related risk factors for the development of hyperkalaemia. The risk for adult patients hospitalised in the University Hospital Zurich between 1 December 2009 and 31 December 2011 of developing hyperkalaemia was correlated with patient characteristics, number, type and duration of potassium-increasing DDIs and frequency of serum potassium monitoring. The 76,467 patients included in this study were prescribed 8,413 potentially severe potassium-increasing DDIs. Patient-related characteristics associated with the development of hyperkalaemia were pulmonary allograft [relative risk (RR) 5.1; p < 0.0001), impaired renal function (RR 2.7; p < 0.0001), diabetes mellitus (RR 1.6; p = 0.002) and female gender (RR 1.5; p = 0.007). Risk factors associated with medication were number of concurrently administered potassium-increasing drugs (RR 3.3 per additional drug; p < 0.0001) and longer duration of the DDI (RR 4.9 for duration ≥6 days; p < 0.0001). Physician-related factors associated with the development of hyperkalaemia were undetermined or elevated serum potassium level before treatment initiation (RR 2.2; p < 0.001) and infrequent monitoring of serum potassium during a DDI (interval >48 h: RR 1.6; p < 0.01). Strategies for reducing the risk of hyperkalaemia during potassium-increasing DDIs should consider both patient- and physician-related risk factors.

Promising effects of xanthine oxidase inhibition by allopurinol on autonomic heart regulation estimated by heart rate variability (HRV) analysis in rats exposed to hypoxia and hyperoxia

PubMed Central

Ziółkowski, Wiesław; Badtke, Piotr; Zajączkowski, Miłosz A.; Flis, Damian J.; Figarski, Adam; Smolińska-Bylańska, Maria; Wierzba, Tomasz H.

2018-01-01

Background It has long been suggested that reactive oxygen species (ROS) play a role in oxygen sensing via peripheral chemoreceptors, which would imply their involvement in chemoreflex activation and autonomic regulation of heart rate. We hypothesize that antioxidant affect neurogenic cardiovascular regulation through activation of chemoreflex which results in increased control of sympathetic mechanism regulating heart rhythm. Activity of xanthine oxidase (XO), which is among the major endogenous sources of ROS in the rat has been shown to increase during hypoxia promote oxidative stress. However, the mechanism of how XO inhibition affects neurogenic regulation of heart rhythm is still unclear. Aim The study aimed to evaluate effects of allopurinol-driven inhibition of XO on autonomic heart regulation in rats exposed to hypoxia followed by hyperoxia, using heart rate variability (HRV) analysis. Material and methods 16 conscious male Wistar rats (350 g): control-untreated (N = 8) and pretreated with Allopurinol-XO inhibitor (5 mg/kg, followed by 50 mg/kg), administered intraperitoneally (N = 8), were exposed to controlled hypobaric hypoxia (1h) in order to activate chemoreflex. The treatment was followed by 1h hyperoxia (chemoreflex suppression). Time-series of 1024 RR-intervals were extracted from 4kHz ECG recording for heart rate variability (HRV) analysis in order to calculate the following time-domain parameters: mean RR interval (RRi), SDNN (standard deviation of all normal NN intervals), rMSSD (square root of the mean of the squares of differences between adjacent NN intervals), frequency-domain parameters (FFT method): TSP (total spectral power) as well as low and high frequency band powers (LF and HF). At the end of experiment we used rat plasma to evaluate enzymatic activity of XO and markers of oxidative stress: protein carbonyl group and 8-isoprostane concentrations. Enzymatic activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were measures in erythrocyte lysates. Results Allopurinol reduced oxidative stress which was the result of hypoxia/hyperoxia, as shown by decreased 8-isoprostane plasma concentration. XO inhibition did not markedly influence HRV parameters in standard normoxia. However, during hypoxia, as well as hyperoxia, allopurinol administration resulted in a significant increase of autonomic control upon the heart as shown by increased SDNN and TSP, with an increased vagal contribution (increased rMSSD and HF), whereas sympathovagal indexes (LF/HF, SDNN/rMSSD) remained unchanged. Conclusions Observed regulatory effects of XO inhibition did not confirm preliminary hypothesis which suggested that an antioxidant such as allopurinol might activate chemoreflex resulting in augmented sympathetic discharge to the heart. The HRV regulatory profile of XO inhibition observed during hypoxia as well as post-hypoxic hyperoxia corresponds to reported reduced risk of sudden cardiovascular events. Therefore our data provide a new argument for therapeutical use of allopurinol in hypoxic conditions. PMID:29432445

Promising effects of xanthine oxidase inhibition by allopurinol on autonomic heart regulation estimated by heart rate variability (HRV) analysis in rats exposed to hypoxia and hyperoxia.

PubMed

Zajączkowski, Stanisław; Ziółkowski, Wiesław; Badtke, Piotr; Zajączkowski, Miłosz A; Flis, Damian J; Figarski, Adam; Smolińska-Bylańska, Maria; Wierzba, Tomasz H

2018-01-01

It has long been suggested that reactive oxygen species (ROS) play a role in oxygen sensing via peripheral chemoreceptors, which would imply their involvement in chemoreflex activation and autonomic regulation of heart rate. We hypothesize that antioxidant affect neurogenic cardiovascular regulation through activation of chemoreflex which results in increased control of sympathetic mechanism regulating heart rhythm. Activity of xanthine oxidase (XO), which is among the major endogenous sources of ROS in the rat has been shown to increase during hypoxia promote oxidative stress. However, the mechanism of how XO inhibition affects neurogenic regulation of heart rhythm is still unclear. The study aimed to evaluate effects of allopurinol-driven inhibition of XO on autonomic heart regulation in rats exposed to hypoxia followed by hyperoxia, using heart rate variability (HRV) analysis. 16 conscious male Wistar rats (350 g): control-untreated (N = 8) and pretreated with Allopurinol-XO inhibitor (5 mg/kg, followed by 50 mg/kg), administered intraperitoneally (N = 8), were exposed to controlled hypobaric hypoxia (1h) in order to activate chemoreflex. The treatment was followed by 1h hyperoxia (chemoreflex suppression). Time-series of 1024 RR-intervals were extracted from 4kHz ECG recording for heart rate variability (HRV) analysis in order to calculate the following time-domain parameters: mean RR interval (RRi), SDNN (standard deviation of all normal NN intervals), rMSSD (square root of the mean of the squares of differences between adjacent NN intervals), frequency-domain parameters (FFT method): TSP (total spectral power) as well as low and high frequency band powers (LF and HF). At the end of experiment we used rat plasma to evaluate enzymatic activity of XO and markers of oxidative stress: protein carbonyl group and 8-isoprostane concentrations. Enzymatic activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were measures in erythrocyte lysates. Allopurinol reduced oxidative stress which was the result of hypoxia/hyperoxia, as shown by decreased 8-isoprostane plasma concentration. XO inhibition did not markedly influence HRV parameters in standard normoxia. However, during hypoxia, as well as hyperoxia, allopurinol administration resulted in a significant increase of autonomic control upon the heart as shown by increased SDNN and TSP, with an increased vagal contribution (increased rMSSD and HF), whereas sympathovagal indexes (LF/HF, SDNN/rMSSD) remained unchanged. Observed regulatory effects of XO inhibition did not confirm preliminary hypothesis which suggested that an antioxidant such as allopurinol might activate chemoreflex resulting in augmented sympathetic discharge to the heart. The HRV regulatory profile of XO inhibition observed during hypoxia as well as post-hypoxic hyperoxia corresponds to reported reduced risk of sudden cardiovascular events. Therefore our data provide a new argument for therapeutical use of allopurinol in hypoxic conditions.

Mortality from bacterial meningitis in children in Kosovo.

PubMed

Namani, Sadie; Milenkovic, Zvonko; Kuchar, Ernest; Koci, Remzie; Mehmeti, Murat

2012-01-01

Bacterial meningitis is a severe infection responsible for high mortality. This prospective study of 277 pediatric bacterial meningitis cases was done to identify factors predicting death in children <16 years of age living and treated in a limited-resources country (Kosovo). Of the 277 children enrolled, 60 patients (22%) developed neurologic complications, and 15 children died (5%). The following variables were strongly correlated with mortality: altered mental status on admission (relative risk [RR] = 29.9), presentation of the initial cerebrospinal fluid as thick pus (RR = 29.9), prehospital seizures (RR = 23.5) and their recurrence >24 hours after admission (RR = 11.5), age <1 month (RR = 19.3), the use of inotropic agents (RR = 11.5), and admission after 5 days' duration of illness (P < .001). The mortality rate in children in Kosovo is similar to those reported from developing countries, and this is most likely due to the unfavorable living conditions.

Complexity of cardiovascular rhythms during head-up tilt test by entropy of patterns.

PubMed

Wejer, Dorota; Graff, Beata; Makowiec, Danuta; Budrejko, Szymon; Struzik, Zbigniew R

2017-05-01

The head-up tilt (HUT) test, which provokes transient dynamical alterations in the regulation of cardiovascular system, provides insights into complex organization of this system. Based on signals with heart period intervals (RR-intervals) and/or systolic blood pressure (SBP), differences in the cardiovascular regulation between vasovagal patients (VVS) and the healthy people group (CG) are investigated. Short-term relations among signal data represented symbolically by three-beat patterns allow to qualify and quantify the complexity of the cardiovascular regulation by Shannon entropy. Four types of patterns: permutation, ordinal, deterministic and dynamical, are used, and different resolutions of signal values in the the symbolization are applied in order to verify how entropy of patterns depends on a way in which values of signals are preprocessed. At rest, in the physiologically important signal resolution ranges, independently of the type of patterns used in estimates, the complexity of SBP signals in VVS is different from the complexity found in CG. Entropy of VVS is higher than CG what could be interpreted as substantial presence of noisy ingredients in SBP of VVS. After tilting this relation switches. Entropy of CG occurs significantly higher than VVS for SBP signals. In the case of RR-intervals and large resolutions, the complexity after the tilt becomes reduced when compared to the complexity of RR-intervals at rest for both groups. However, in the case of VVS patients this reduction is significantly stronger than in CG. Our observations about opposite switches in entropy between CG and VVS might support a hypothesis that baroreflex in VVS affects stronger the heart rate because of the inefficient regulation (possibly impaired local vascular tone alternations) of the blood pressure.

RR Lyrae, Delta Scuti, SX Phoenicis stars and Baade-Wesselink method. I - Photometric and radial velocity measurements of four field stars - RR Cet, DX Del, BS AQR and DY Peg

NASA Astrophysics Data System (ADS)

Meylan, G.; Burki, G.; Rufener, F.; Mayor, M.; Burnet, M.; Ischi, E.

1986-04-01

Simultaneous measurements in the Geneva seven-color photometry and in radial velocities with the spectrophotometer CORAVEL for two RR Lyrae, one Delta Scuti and one SX Phoenicis field star were obtained in order to apply the Baade-Wesselink method to these kinds of variable stars. As a first step, the data regarding the RR Cet, DX Del, BS Aqr, and DY Peg are presented. The target of this study will consist in determining the physical parameters (temperature, gravity, metal content, mass, luminosity) and distances of these stars.

Resonance Raman Spectroscopy of human brain metastasis of lung cancer analyzed by blind source separation

NASA Astrophysics Data System (ADS)

Zhou, Yan; Liu, Cheng-Hui; Pu, Yang; Cheng, Gangge; Yu, Xinguang; Zhou, Lixin; Lin, Dongmei; Zhu, Ke; Alfano, Robert R.

2017-02-01

Resonance Raman (RR) spectroscopy offers a novel Optical Biopsy method in cancer discrimination by a means of enhancement in Raman scattering. It is widely acknowledged that the RR spectrum of tissue is a superposition of spectra of various key building block molecules. In this study, the Resonance Raman (RR) spectra of human metastasis of lung cancerous and normal brain tissues excited by a visible selected wavelength at 532 nm are used to explore spectral changes caused by the tumor evolution. The potential application of RR spectra human brain metastasis of lung cancer was investigated by Blind Source Separation such as Principal Component Analysis (PCA). PCA is a statistical procedure that uses an orthogonal transformation to convert a set of observations of possibly correlated variables into a set of values of linearly uncorrelated variables called principal components (PCs). The results show significant RR spectra difference between human metastasis of lung cancerous and normal brain tissues analyzed by PCA. To evaluate the efficacy of for cancer detection, a linear discriminant analysis (LDA) classifier is utilized to calculate the sensitivity, and specificity and the receiver operating characteristic (ROC) curves are used to evaluate the performance of this criterion. Excellent sensitivity of 0.97, specificity (close to 1.00) and the Area Under ROC Curve (AUC) of 0.99 values are achieved under best optimal circumstance. This research demonstrates that RR spectroscopy is effective for detecting changes of tissues due to the development of brain metastasis of lung cancer. RR spectroscopy analyzed by blind source separation may have potential to be a new armamentarium.

Synthetic cannabinoid and marijuana exposures reported to poison centers.

PubMed

Forrester, M B; Kleinschmidt, K; Schwarz, E; Young, A

2012-10-01

Synthetic cannabinoids have recently gained popularity as a recreational drug because they are believed to result in a marijuana-like high. This investigation compared synthetic cannabinoids and marijuana exposures reported to a large statewide poison center system. Synthetic cannabinoid and marijuana exposures reported to Texas poison centers during 2010 were identified. The distribution of exposures to the two agents with respect to various demographic and clinical factors were compared by calculating the rate ratio (RR) of the synthetic cannabinoid and marijuana percentages for each subgroup and 95% confidence interval (CI). The proportion of synthetic cannabinoid and marijuana exposures, respectively, were 87.3% and 46.5% via inhalation (RR 1.88, 95% CI 1.38-2.61), 74.9% and 65.7% in male (RR 1.14, 95% CI 0.87-1.51), 40.2% and 56.6% age ≤ 19 years (RR 0.71, 95% CI 0.52-0.98), 79.2% and 58.6% occurring at a residence (RR 1.35, 95% CI 1.02-1.82), 8.4% and 16.2% managed on-site (RR 0.52. 95% CI 0.28-1.00), and 59.3% and 41.4% with serious medical outcomes (RR 1.43, 95% CI 1.03-2.05). Compared to marijuana, synthetic cannabinoid exposures were more likely to be used through inhalation, to involve adults, to be used at a residence, and to result in serious outcomes.

Study of Nevi in Children (SONIC): Baseline Findings and Predictors of Nevus Count

PubMed Central

Satagopan, Jaya M.; Geller, Alan C.; Dusza, Stephen W.; Weinstock, Martin A.; Berwick, Marianne; Bishop, Marilyn; Heneghan, Maureen K.; Halpern, Allan C.

2009-01-01

The authors report baseline findings and predictors of nevus count (log total nevi) at the completion of year 1 (2004) of the first known population-based, prospective study of nevi in a US cohort of children. Overall, 64% (n = 443/691) of grade 5 students and their parents in Framingham, Massachusetts, completed surveys and underwent digital photography. Total nevus count was associated with skin and hair color and tendency to burn, as measured by a sun sensitivity index. In multivariate analyses, male gender (rate ratio (RR) = 1.38, 95% confidence interval (CI): 1.22, 1.55; P < 0.0001), spending 5–6 weekly hours outdoors between 10 AM and 4 PM (RR = 1.13, 95% CI: 1.00, 1.28; P = 0.051), getting a painful sunburn once (RR = 1.24, 95% CI: 0.98, 1.57; P = 0.073) and at least twice (RR = 1.34, 95% CI: 0.99, 1.82; P = 0.061), and wearing a shirt at the beach or pool rarely (RR = 1.29, 95% CI: 1.08, 1.54; P = 0.005), sometimes (RR = 1.26, 95% CI: 1.01, 1.57; P = 0.041), and often and always (RR = 1.32, 95% CI: 1.13, 1.54; P = 0.001) were associated with increased number of nevi. Identifying factors that predict the development of nevi will improve primary prevention efforts during early life. PMID:19001133

A Meta-Analysis for Postoperative Complications in Tibial Plafond Fracture: Open Reduction and Internal Fixation Versus Limited Internal Fixation Combined With External Fixator.

PubMed

Wang, Dong; Xiang, Jian-Ping; Chen, Xiao-Hu; Zhu, Qing-Tang

2015-01-01

The treatment of tibial plafond fractures is challenging to foot and ankle surgeons. Open reduction and internal fixation and limited internal fixation combined with an external fixator are 2 of the most commonly used methods of tibial plafond fracture repair. However, conclusions regarding the superior choice remain controversial. The present meta-analysis aimed to quantitatively compare the postoperative complications between open reduction and internal fixation and limited internal fixation combined with an external fixator for tibial plafond fractures. Nine studies with 498 fractures in 494 patients were included in the present study. The meta-analysis found no significant differences in bone healing complications (risk ratio [RR] 1.17, 95% confidence interval [CI] 0.68 to 2.01, p = .58], nonunion (RR 1.09, 95% CI 0.51 to 2.36, p = .82), malunion or delayed union (RR 1.24, 95% CI 0.57 to 2.69, p = .59), superficial (RR 1.56, 95% CI 0.43 to 5.61, p = .50) and deep (RR 1.89, 95% CI 0.62 to 5.80) infections, arthritis symptoms (RR 1.20, 95% CI 0.92 to 1.58, p = .18), or chronic osteomyelitis (RR 0.31, 95% CI 0.05 to 1.84, p = .20) between the 2 groups. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

A method for analyzing temporal patterns of variability of a time series from Poincare plots.

PubMed

Fishman, Mikkel; Jacono, Frank J; Park, Soojin; Jamasebi, Reza; Thungtong, Anurak; Loparo, Kenneth A; Dick, Thomas E

2012-07-01

The Poincaré plot is a popular two-dimensional, time series analysis tool because of its intuitive display of dynamic system behavior. Poincaré plots have been used to visualize heart rate and respiratory pattern variabilities. However, conventional quantitative analysis relies primarily on statistical measurements of the cumulative distribution of points, making it difficult to interpret irregular or complex plots. Moreover, the plots are constructed to reflect highly correlated regions of the time series, reducing the amount of nonlinear information that is presented and thereby hiding potentially relevant features. We propose temporal Poincaré variability (TPV), a novel analysis methodology that uses standard techniques to quantify the temporal distribution of points and to detect nonlinear sources responsible for physiological variability. In addition, the analysis is applied across multiple time delays, yielding a richer insight into system dynamics than the traditional circle return plot. The method is applied to data sets of R-R intervals and to synthetic point process data extracted from the Lorenz time series. The results demonstrate that TPV complements the traditional analysis and can be applied more generally, including Poincaré plots with multiple clusters, and more consistently than the conventional measures and can address questions regarding potential structure underlying the variability of a data set.

Low dimensional model of heart rhythm dynamics as a tool for diagnosing the anaerobic threshold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anosov, O.L.; Butkovskii, O.Y.; Kadtke, J.

We report preliminary results on describing the dependence of the heart rhythm variability on the stress level by using qualitative, low dimensional models. The reconstruction of macroscopic heart models yielding cardio cycles (RR-intervals) duration was based on actual clinical data. Our results show that the coefficients of the low dimensional models are sensitive to metabolic changes. In particular, at the transition between aerobic and aerobic-anaerobic metabolism, there are pronounced extrema in the functional dependence of the coefficients on the stress level. This strong sensitivity can be used to design an easy indirect method for determining the anaerobic threshold. This methodmore » could replace costly and invasive traditional methods such as gas analysis and blood tests. {copyright} {ital 1997 American Institute of Physics.}« less

VizieR Online Data Catalog: Abundances of 8 RR Lyrae subclass C variable stars (Govea+, 2014)

NASA Astrophysics Data System (ADS)

Govea, J.; Gomez, T.; Preston, G. W.; Sneden, C.

2016-02-01

We chose 10 candidate RR Lyrae variable stars of subclass c (RRc) stars for spectroscopic observation. Many of these stars were first identified as RRc variables by the All Sky Automated Survey (ASAS) of Pojmanski 2003 (cat. II/264). The target star list included ASAS 144154-0324.7 and ASAS 204440-2402.7. But our spectroscopic study suggest that these two stars are probably W UMa binaries instead of RR Lyrae stars Our spectra were obtained with the echelle spectrograph of the du Pont 2.5m telescope at the Las Campanas Observatory. Four observing runs during 2009-2010 were partly devoted to this project. The spectrograph was used with the 1.5*4'' entrance slit, which translates to a resolving power of R=λ/Δλ~27000 at the MgI b lines near 5180Å. The total continuous wavelength coverage of the spectra was 3500-9000Å. (6 data files).

Clinical, Electrocardiographic, and Echocardiographic Parameter Combination Predicts the Onset of Atrial Fibrillation.

PubMed

Soeki, Takeshi; Matsuura, Tomomi; Tobiume, Takeshi; Bando, Sachiko; Matsumoto, Kazuhisa; Nagano, Hiromi; Uematsu, Etsuko; Kusunose, Kenya; Ise, Takayuki; Yamaguchi, Koji; Yagi, Shusuke; Fukuda, Daiju; Yamada, Hirotsugu; Wakatsuki, Tetsuzo; Shimabukuro, Michio; Sata, Masataka

2018-05-30

The ability to identify risk markers for new-onset atrial fibrillation (AF) is critical to the development of preventive strategies, but it remains unknown whether a combination of clinical, electrocardiographic, and echocardiographic parameters predicts the onset of AF. In the present study, we evaluated the predictive value of a combined score that includes these parameters.Methods and Results:We retrospectively studied 1,040 patients without AF who underwent both echocardiography and 24-h Holter electrocardiography between May 2005 and December 2010. During a median follow-up period of 68.4 months (IQR, 49.9-93.3 months), we investigated the incidence of new-onset AF. Of the 1,040 patients, 103 (9.9%) developed AF. Patients who developed AF were older than patients who did not. Total heart beats, premature atrial contraction (PAC) count, maximum RR interval, and frequency of sinus pause quantified on 24-h electrocardiography were associated with new-onset AF. LA diameter (LAD) on echocardiography was also associated with the development of AF. On multivariate Cox analysis, age ≥58 years, PAC count ≥80 beats/day, maximum RR interval ≥1.64 s, and LAD ≥4.5 cm were independently associated with the development of AF. The incidence rate of new-onset AF significantly increased as the combined score (i.e., the sum of the risk score determined using hazard ratios) increased. A combined score that includes age, PAC count, maximum RR interval, and LAD could help characterize the risk of new-onset AF.

Alcohol intake is associated with increased risk of squamous cell carcinoma of the skin: three US prospective cohort studies

PubMed Central

Siiskonen, Satu; Han, Jiali; Li, Tricia; Cho, Eunyoung

2016-01-01

The association between alcohol intake and cutaneous squamous cell carcinoma (cSCC) is unclear. We studied the association between alcohol intake and incident invasive cSCC in three cohorts of women and men with repeated assessments of alcohol intake in the US. Information on alcohol intake was collected repeatedly during follow-up. Cumulative average of alcohol intakes was used. Multivariable Cox proportional hazards models with time-dependent exposure were used to estimate relative risks (RR) and 95% confidence intervals, followed by a meta-analysis. During a follow-up of 4,234,416 person-years, 2,938 cSCC were identified. Alcohol intake was associated with an increased risk of cSCC with a dose-response relationship. Each additional drink (12.8 gram of alcohol) per day was associated with a 22% increased risk of cSCC (RR 1.22, 95% confidence interval: 1.13 to 1.31). White wine consumption of ≥5 times/wk was associated with an increased risk of cSCC (RR 1.31, 95% confidence interval: 1.09 to 1.59). We found no increased risk of cSCC with other alcoholic beverages. The population attributable risk associated with alcohol intake of ≥20 grams/d was 3% of cSCCs. In conclusion, alcohol intake was associated with an elevated risk of cSCC. Among alcoholic beverages, white wine was associated with cSCC. PMID:27145335

Properties of Asymmetric Detrended Fluctuation Analysis in the time series of RR intervals

NASA Astrophysics Data System (ADS)

Piskorski, J.; Kosmider, M.; Mieszkowski, D.; Krauze, T.; Wykretowicz, A.; Guzik, P.

2018-02-01

Heart rate asymmetry is a phenomenon by which the accelerations and decelerations of heart rate behave differently, and this difference is consistent and unidirectional, i.e. in most of the analyzed recordings the inequalities have the same directions. So far, it has been established for variance and runs based types of descriptors of RR intervals time series. In this paper we apply the newly developed method of Asymmetric Detrended Fluctuation Analysis, which so far has mainly been used with economic time series, to the set of 420 stationary 30 min time series of RR intervals from young, healthy individuals aged between 20 and 40. This asymmetric approach introduces separate scaling exponents for rising and falling trends. We systematically study the presence of asymmetry in both global and local versions of this method. In this study global means "applying to the whole time series" and local means "applying to windows jumping along the recording". It is found that the correlation structure of the fluctuations left over after detrending in physiological time series shows strong asymmetric features in both magnitude, with α+ <α-, where α+ is related to heart rate decelerations and α- to heart rate accelerations, and the proportion of the signal in which the above inequality holds. A very similar effect is observed if asymmetric noise is added to a symmetric self-affine function. No such phenomena are observed in the same physiological data after shuffling or with a group of symmetric synthetic time series.

Influence of cigarette smoking on human autonomic function

NASA Technical Reports Server (NTRS)

Niedermaier, O. N.; Smith, M. L.; Beightol, L. A.; Zukowska-Grojec, Z.; Goldstein, D. S.; Eckberg, D. L.

1993-01-01

BACKGROUND. Although cigarette smoking is known to lead to widespread augmentation of sympathetic nervous system activity, little is known about the effects of smoking on directly measured human sympathetic activity and its reflex control. METHODS AND RESULTS. We studied the acute effects of smoking two research-grade cigarettes on muscle sympathetic nerve activity and on arterial baroreflex-mediated changes of sympathetic and vagal neural cardiovascular outflows in eight healthy habitual smokers. Measurements were made during frequency-controlled breathing, graded Valsalva maneuvers, and carotid baroreceptor stimulation with ramped sequences of neck pressure and suction. Smoking provoked the following changes: Arterial pressure increased significantly, and RR intervals, RR interval spectral power at the respiratory frequency, and muscle sympathetic nerve activity decreased. Plasma nicotine levels increased significantly, but plasma epinephrine, norepinephrine, and neuropeptide Y levels did not change. Peak sympathetic nerve activity during and systolic pressure overshoots after Valsalva straining increased significantly in proportion to increases of plasma nicotine levels. The average carotid baroreceptor-cardiac reflex relation shifted rightward and downward on arterial pressure and RR interval axes; average gain, operational point, and response range did not change. CONCLUSIONS. In habitual smokers, smoking acutely reduces baseline levels of vagal-cardiac nerve activity and completely resets vagally mediated arterial baroreceptor-cardiac reflex responses. Smoking also reduces muscle sympathetic nerve activity but augments increases of sympathetic activity triggered by brief arterial pressure reductions. This pattern of autonomic changes is likely to influence smokers' responses to acute arterial pressure reductions importantly.

Cognitive impairment and risk of future stroke: a systematic review and meta-analysis

PubMed Central

Lee, Meng; Saver, Jeffrey L.; Hong, Keun-Sik; Wu, Yi-Ling; Liu, Hsing-Cheng; Rao, Neal M.; Ovbiagele, Bruce

2014-01-01

Background: Several studies have assessed the link between cognitive impairment and risk of future stroke, but results have been inconsistent. We conducted a systematic review and meta-analysis of cohort studies to determine the association between cognitive impairment and risk of future stroke. Methods: We searched MEDLINE and Embase (1966 to November 2013) and conducted a manual search of bibliographies of relevant retrieved articles and reviews. We included cohort studies that reported multivariable adjusted relative risks and 95% confidence intervals or standard errors for stroke with respect to baseline cognitive impairment. Results: We identified 18 cohort studies (total 121 879 participants) and 7799 stroke events. Pooled analysis of results from all studies showed that stroke risk increased among patients with cognitive impairment at baseline (relative risk [RR] 1.39, 95% confidence interval [CI] 1.24–1.56). The results were similar when we restricted the analysis to studies that used a widely adopted definition of cognitive impairment (i.e., Mini-Mental State Examination score < 25 or nearest equivalent) (RR 1.64, 95% CI 1.46–1.84). Cognitive impairment at baseline was also associated with an increased risk of fatal stroke (RR 1.68, 95% CI 1.21–2.33) and ischemic stroke (RR 1.65, 95% CI 1.41–1.93). Interpretation: Baseline cognitive impairment was associated with a significantly higher risk of future stroke, especially ischemic and fatal stroke. PMID:25157064

Use of fertility drugs and risk of uterine cancer: results from a large Danish population-based cohort study.

PubMed

Jensen, Allan; Sharif, Heidi; Kjaer, Susanne K

2009-12-01

Some epidemiologic studies have indicated that uterine cancer risk may be increased after use of fertility drugs. To further assess this association, the authors used data from a large cohort of 54,362 women diagnosed with infertility who were referred to Danish fertility clinics between 1965 and 1998. In a case-cohort study, rate ratios and 95% confidence intervals were used to assess the effects of 4 groups of fertility drugs on overall risk of uterine cancer after adjustment for potentially confounding factors. Through mid-2006, 83 uterine cancers were identified. Ever use of any fertility drug was not associated with uterine cancer risk (rate ratio (RR) = 1.10, 95% confidence interval (CI): 0.69, 1.76). However, ever use of gonadotropins (follicle-stimulating hormone and human menopausal gonadotropin) increased uterine cancer risk (RR = 2.21, 95% CI: 1.08, 4.50); the risk was primarily observed after 10 years of follow-up. Furthermore, uterine cancer risk increased with number of cycles of use for clomiphene (for > or =6 cycles, RR = 1.96, 95% CI: 1.03, 3.72) and human chorionic gonadotropin (for > or =6 cycles, RR = 2.18, 95% CI: 1.16, 4.08) but not for other gonadotropins. Use of gonadotropin-releasing hormone analogs was not associated with risk. Gonadotropins, and possibly clomiphene and human chorionic gonadotropin, may increase the risk of uterine cancer, with higher doses and longer follow-up leading to greater risk.

Association between obesity and heart rate variability indices: an intuition toward cardiac autonomic alteration - a risk of CVD.

PubMed

Yadav, Ram Lochan; Yadav, Prakash Kumar; Yadav, Laxmi Kumari; Agrawal, Kopila; Sah, Santosh Kumar; Islam, Md Nazrul

2017-01-01

Obese people have a higher prevalence of cardiovascular disease, which is supposed to be due to autonomic dysfunction and/or metabolic disorder. The alterations in cardiac autonomic functions bring out the changes in the heart rate variability (HRV) indicators, an assessing tool for cardiac autonomic conditions. To compare the cardiac autonomic activity between obese and normal weight adults and find out the highest association between the indices of HRV and obesity. The study was conducted in 30 adult obese persons (body mass index [BMI] >30 kg/m 2 ) and 29 healthy normal weight controls (BMI 18-24 kg/m 2 ). Short-term HRV variables were assessed using standard protocol. Data were compared between groups using Mann-Whitney U test. Obesity indices such as waist circumference, hip circumference, waist-hip ratio (WHR), and BMI were measured and calculated, and they were correlated with HRV indices using Spearman's correlation analysis. In the obese group, there was a significant increase in the mean heart rate, whereas the HRV parasympathetic indicators were less (eg, root mean square of differences of successive RR intervals [28.75 {16.72-38.35} vs 41.55 {30.6-56.75} ms, p =0.018], number of RR intervals that differ by >50 ms, that is, NN50 [15.5 {2-39} vs 83.5 {32.75-116.25}, p =0.010], etc) and the sympathetic indicator low frequency (LF)/high frequency (HF) ratio (1.2 [0.65-2.20] vs 0.79 [0.5-1.02], p =0.045) was more than that of the normal weight group. Spearman's correlation between HRV and obesity indices showed significant positive correlation of WHR with LF in normalized unit ( r =0.478, p <0.01) and LF/HF ratio ( r =0.479, p <0.01), whereas it had significant negative correlation with high frequency power ms 2 ( r =-0.374, p <0.05) and HF in normalized unit ( r =-0.478, p <0.01). There was a nonsignificant correlation of BMI with HRV variables in obese individuals. Increased WHR, by far an indicator of visceral adiposity, was strongly associated with reduced cardiac parasympathetic and increased sympathetic activity in obese individuals defined by BMI. However, BMI itself has a weak relationship with HRV cardiac autonomic markers. Thus, even with a slight increase in WHR in an individual, there could be a greater risk of cardiovascular morbidity and mortality brought about by cardiac autonomic alterations.

Methods to Obtain a Representative Sample of Ryan White-Funded Patients for a Needs Assessment in Los Angeles County: Results from a Replicable Approach.

PubMed

Dierst-Davies, Rhodri; Wohl, Amy Rock; Pinney, Glenda; Johnson, Christopher H; Vincent-Jones, Craig; Pérez, Mario J

The Health Resources and Services Administration requires that jurisdictions receiving Ryan White (RW) funding justify need, set priorities, and provide allocations using evidence-based methods. Methods and results from the 2011 Los Angeles Coordinated HIV/AIDS Needs Assessment-Care (LACHNA-Care) study are presented. Individual-level weights were applied to expand the sample from 400 to 18 912 persons, consistent with the 19 915 clients in the system. Awareness, need, and utilization for medical outpatient care were high (>90%). Other services (eg, child care) had limited awareness (21%). Majority of participants reported at least 1 service gap (81%). Lack of insurance (risk ratio [RR] = 3.0, 95% confidence interval [CI]: 1.5-6.2), substance use (RR = 2.9, 95% CI: 1.3-6.4), and past lapses in medical care (RR = 2.8, 95% CI: 1.3-5.9) were associated with gaps. Within clusters, past incarceration was associated with gaps for housing (RR = 13.5, 95% CI: 3.5-52.1), transportation (RR = 3.2, 95% CI: 1.2-8.4), and case management (RR = 4.0, 95% CI: 1.3-12.2). Applied methods resulted in representative data instrumental to RW program planning efforts.

Epilepsy is associated with ventricular alterations following convulsive status epilepticus in children.

PubMed

Ali, Wail; Bubolz, Beth A; Nguyen, Linh; Castro, Danny; Coss-Bu, Jorge; Quach, Michael M; Kennedy, Curtis E; Anderson, Anne E; Lai, Yi-Chen

2017-12-01

Convulsive status epilepticus can exert profound cardiovascular effects in adults including ventricular depolarization-repolarization abnormalities. Whether status epilepticus adversely affects ventricular electrical properties in children is less understood. Therefore, we sought to characterize ventricular alterations and the associated clinical factors in children following convulsive status epilepticus. We conducted a 2-year retrospective, case-control study. Children between 1 month and 21 years of age were included if they were admitted to the pediatric intensive care unit with primary diagnosis of convulsive status epilepticus and had 12-lead electrocardiogram (ECG) within 24 hours of admission. Children with heart disease, ion channelopathy, or on vasoactive medications were excluded. Age-matched control subjects had no history of seizures or epilepsy. The primary outcome was ventricular abnormalities represented by ST segment changes, abnormal T wave, QRS axis deviation, and corrected QT (QTc) interval prolongation. The secondary outcomes included QT/RR relationship, beat-to-beat QTc interval variability, ECG interval measurement between groups, and clinical factors associated with ECG abnormalities. Of 317 eligible children, 59 met the inclusion criteria. History of epilepsy was present in 31 children (epileptic) and absent in 28 children (non-epileptic). Compared with the control subjects (n = 31), the status epilepticus groups were more likely to have an abnormal ECG with overall odds ratio of 3.8 and 7.0 for the non-epileptic and the epileptic groups respectively. Simple linear regression analysis demonstrated that children with epilepsy exhibited impaired dependence and adaptation of the QT interval on heart rate. Beat-to-beat QTc interval variability, a marker of ventricular repolarization instability, was increased in children with epilepsy. Convulsive status epilepticus can adversely affect ventricular electrical properties and stability in children, especially those with epilepsy. These findings suggest that children with epilepsy may be particularly vulnerable to seizure-induced arrhythmias. Therefore postictal cardiac surveillance may be warranted in this population.

Citation Analysis and Trends in review articles in dentistry.

PubMed

Muniz, Francisco Wilker Mustafa Gomes; Celeste, Roger Keller; Oballe, Harry Juan Rivera; Rösing, Cassiano Kuchenbecker

2018-06-01

This study aimed to describe the trends in dentistry article reviews as well as to compare citation patterns between systematic and narrative reviews. A search strategy was developed, in Scopus database, in order to identify all narrative and systematic reviews published between 2000 and 2015. Original research studies, letters to the editor, editorials, book chapters, and case reports were excluded. From the list of studies available, 30 reviews per year were randomly chosen. The review type, year of publication, number of authors, country of the first author, open access, language, main topic of interest, journal's H index, number of references, and number of citations were extracted by 2 researchers. The number of citations was extracted from the Scopus database. Multivariable regression analysis was used in order to detect the association between citation rate and the independent variables. Overall, 118 and 362 systematic and narrative reviews were included in this study. Throughout the years, the number of systematic reviews has increased from 5.8% to 53.3%. However, the mean number of citations has significantly decreased, and this is affected by the review's year of publication. A trend for lower citation in systematic reviews (Relative risk [RR]: 0.79; 95% confidence interval: 0.75-0.84) has been demonstrated; however, the number of citations of narrative reviews has been increasing over the years (RR: 1.14; 95% confidence interval: 1.08-1.21). From 2000 to 2015, the number of systematic reviews increased substantially. On the other hand, a trend for lower citations of these studies has been observed that is affected over time. Copyright © 2017 Elsevier Inc. All rights reserved.

Minimal Window Duration for Accurate HRV Recording in Athletes.

PubMed

Bourdillon, Nicolas; Schmitt, Laurent; Yazdani, Sasan; Vesin, Jean-Marc; Millet, Grégoire P

2017-01-01

Heart rate variability (HRV) is non-invasive and commonly used for monitoring responses to training loads, fitness, or overreaching in athletes. Yet, the recording duration for a series of RR-intervals varies from 1 to 15 min in the literature. The aim of the present work was to assess the minimum record duration to obtain reliable HRV results. RR-intervals from 159 orthostatic tests (7 min supine, SU, followed by 6 min standing, ST) were analyzed. Reference windows were 4 min in SU (min 3-7) and 4 min in ST (min 9-13). Those windows were subsequently divided and the analyses were repeated on eight different fractioned windows: the first min (0-1), the second min (1-2), the third min (2-3), the fourth min (3-4), the first 2 min (0-2), the last 2 min (2-4), the first 3 min (0-3), and the last 3 min (1-4). Correlation and Bland & Altman statistical analyses were systematically performed. The analysis window could be shortened to 0-2 instead of 0-4 for RMSSD only, whereas the 4-min window was necessary for LF and total power. Since there is a need for 1 min of baseline to obtain a steady signal prior the analysis window, we conclude that studies relying on RMSSD may shorten the windows to 3 min (= 1+2) in SU or seated position only and to 6 min (= 1+2 min SU plus 1+2 min ST) if there is an orthostatic test. Studies relying on time- and frequency-domain parameters need a minimum of 5 min (= 1+4) min SU or seated position only but require 10 min (= 1+4 min SU plus 1+4 min ST) for the orthostatic test.

The differences between patients with panic disorder and healthy controls in psychophysiological stress profile.

PubMed

Kotianova, Antonia; Kotian, Michal; Slepecky, Milos; Chupacova, Michaela; Prasko, Jan; Tonhajzerova, Ingrid

2018-01-01

Alarming somatic symptoms, in particular, cardiovascular symptoms, are the characteristic feature of panic attacks. Increased cardiac mortality and morbidity have been found in these patients. Power spectral analysis of electrocardiogram R-R intervals is known to be a particularly successful tool in the detection of autonomic instabilities in various clinical disorders. Our study aimed to compare patients with panic disorder and healthy controls in heart rate variation (HRV) parameters (very-low-frequency [VLF], low-frequency [LF], and high-frequency [HF] band components of R-R interval) in baseline and during the response to the mental task. We assessed psychophysiological variables in 33 patients with panic disorder (10 men, 23 women; mean age 35.9±10.7 years) and 33 age- and gender-matched healthy controls (10 men, 23 women; mean age 35.8±12.1 years). Patients were treatment naïve. Heart rate, blood pressure, muscle tension, and HRV in basal conditions and after the psychological task were assessed. Power spectrum was computed for VLF (0.003-0.04 Hz), LF (0.04-0.15 Hz), and HF (0.15-0.40 Hz) bands using fast Fourier transformation. In the baseline period, the VLF band was significantly lower in panic disorder group compared to controls ( p <0.005). In the period of mental task, the LF/HF ratio was significantly higher in panic disorder patients compared to controls ( p <0.05). No significant differences were found in the remaining parameters. There was a significant difference in ΔHF and ΔLF/HF ratio between patients and controls, with Δ increasing in patients and decreasing in controls. These findings revealed that patients suffering from panic disorder were characterized by relative sympathetic dominance (reactivity) in response to mental stress compared with healthy controls.

Catheter-Based Renal Sympathetic Denervation Significantly Inhibits Atrial Fibrillation Induced by Electrical Stimulation of the Left Stellate Ganglion and Rapid Atrial Pacing

PubMed Central

Po, Sunny S.; Wang, Huan; Zhang, Ling; Zhang, Feng; Wang, Kun; Zhou, Qina

2013-01-01

Background Sympathetic activity involves the pathogenesis of atrial fibrillation (AF). Renal sympathetic denervation (RSD) decreases sympathetic renal afferent nerve activity, leading to decreased central sympathetic drive. The aim of this study was to identify the effects of RSD on AF inducibility induced by hyper-sympathetic activity in a canine model. Methods To establish a hyper-sympathetic tone canine model of AF, sixteen dogs were subjected to stimulation of left stellate ganglion (LSG) and rapid atrial pacing (RAP) for 3 hours. Then animals in the RSD group (n = 8) underwent radiofrequency ablation of the renal sympathetic nerve. The control group (n = 8) underwent the same procedure except for ablation. AF inducibility, effective refractory period (ERP), ERP dispersion, heart rate variability and plasma norepinephrine levels were measured at baseline, after stimulation and after ablation. Results LSG stimulation combined RAP significantly induced higher AF induction rate, shorter ERP, larger ERP dispersion at all sites examined and higher plasma norepinephrine levels (P<0.05 in all values), compared to baseline. The increased AF induction rate, shortened ERP, increased ERP dispersion and elevated plasma norepinephrine levels can be almost reversed by RSD, compared to the control group (P<0.05). LSG stimulation combined RAP markedly shortened RR-interval and standard deviation of all RR-intervals (SDNN), Low-frequency (LF), high-frequency (HF) and LF/HF ratio (P<0.05). These changes can be reversed by RSD, compared to the control group (P<0.05). Conclusions RSD significantly reduced AF inducibility and reversed the atrial electrophysiological changes induced by hyper-sympathetic activity. PMID:24223140

[Effectiveness of the "Five-Day Plan to Stop Smoking" in a city in Argentina].

PubMed

Alfaro, Mariana Elizabeth; Simi, Marcelo Ricardo

2007-05-01

To evaluate the effectiveness of the "Five-Day Plan to Stop Smoking" at the end of the intervention and after one year in a sample of participants in the city of Rosario, Santa Fe, Argentina. The quasi-experimental, longitudinal, prospective cohort, comparative study was based on the evaluation of the effectiveness of the "Five-Day Plan to Stop Smoking" in Rosario, Argentina, with eight groups of participants. Each session of the five-night course included presentations on medical aspects of smoking, an emphasis on group support in quitting, and relaxation techniques. The eight groups included a total of 739 people (50.5% of them women and 49.5% men). Using a sample of 281 participants who were chosen at random, effectiveness was evaluated immediately after the end of each course and again after one year. Effectiveness was assessed in relation to the age the subjects began smoking, the average daily consumption of cigarettes, the number of years participants had smoked, their educational level, the number of previous attempts to quit smoking, and the level of nicotine dependence as measured by the Fagerström scale. Association among qualitative variables was determined using relative risk (RR), with 95% confidence intervals. Differences in the means of quantitative variables were determined using the t test for independent samples. The chi-square test was used to establish differences among the categorical variables studied. Of the 281 participants (138 men and 143 women) in the sample, 201 (71.5%) (104 men and 97 women) quit smoking by the end of the course, and 77 (27.4%) (48 men and 29 women) did not smoke after one year. There was a significant association between relapse and female gender (RR = 1.22; P = 0.005), as was there for a score > or = 7 on the Fagerström scale of nicotine dependence (RR = 1.17; P = 0.03). Beginning to smoke before the age of 20 was a protective factor against relapse among those attending the "Five-Day Plan to Stop Smoking" courses. The most frequent determinants of relapse were abstinence syndrome symptoms (40.3%) and stressful situations (28.2%). The "Five-Day Plan to Stop Smoking" is an effective tool for secondary prevention of smoking. In the study population its effectiveness was associated with male gender and with a lower level of nicotine dependence.

A retrospective cohort study of Parkinson's disease in Korean shipbuilders.

PubMed

Park, Jungsun; Yoo, Cheol-In; Sim, Chang Sun; Kim, Jae Woo; Yi, Yunjeong; Shin, Yong Chul; Kim, Dae-Hyun; Kim, Yangho

2006-05-01

We performed a retrospective cohort study in South Korea to clarify the role of occupational exposure, especially to welding, in the etiology of Parkinson's disease (PD). We constructed a database of subjects classified into an exposure group (blue-collar workers) and a non-exposure group (white-collar workers) in two shipbuilding companies. Jobs of blue-collar workers were categorized into the first group of welding, the second group of fitting, grinding and finishing, cutting, and the other group. To determine new cases of PD during the follow-up period (1992-2003), we used the physician billing claims database of the National Health Insurance Corporation. For the detected PD patients in the physician billing claims database, a neurologist in our research team confirmed the appropriateness of each diagnosis by reviewing medical charts. Based on the review, we confirmed the numbers of new cases of PD and calculated the relative risk (RR) and the 95% confidence intervals (CI) by Cox regression analysis. In a backward selection procedure, 'age' was a significant independent variable but exposure was not. Furthermore, the RR in welders (high exposure group) was also insignificant and less than that in others (very low exposure group). This longitudinal study of shipbuilding workers supports our previous case-control studies suggesting that exposure to manganese does not increase the risk of PD.

Employee and Customer Injury During Violent Crimes in Retail and Service Businesses

PubMed Central

Peek-Asa, Corinne; Casteel, Carri; Kraus, Jess F.; Whitten, Paul

2006-01-01

Objectives. We sought to compare the frequency and risk factors for employees and customers injured during crimes in retail (convenience, grocery, and liquor stores) and service businesses (bars, restaurants, motels). Methods. A total of 827 retail and service businesses in Los Angeles were randomly selected. Police crime reports (n=2029) from violent crimes that occurred in these businesses from January 1996 through June 2001 were individually reviewed to determine whether a customer or an employee was injured and to collect study variables. Results. A customer injury was 31% more likely (95% confidence interval [CI]=1.11, 1.51) than an employee injury during a violent crime. Customer injury was more frequent than employee injury during violent crimes in bars, restaurants, convenience stores, and motels but less likely in grocery or liquor stores. Injury risk was increased for both employees and customers when resisting the perpetrator and when the perpetrator was suspected of using alcohol. Customers had an increased risk for injury during crimes that occurred outside (relative risk [RR]=2.01; 95% CI=1.57, 2.58) and at night (RR=1.79; 95% CI=1.40, 2.29). Conclusions. Security programs should be designed to protect customers as well as employees. PMID:17008585

Lidocaine dose-response effect on postoperative cognitive deficit: meta-analysis and meta-regression.

PubMed

Habibi, Mohammad Reza; Habibi, Valiollah; Habibi, Ali; Soleimani, Aria

2018-04-01

The true influence of the perioperative intravenous lidocaine on the development of postoperative cognitive deficit (POCD) in coronary artery bypass grafting (CABG) remains controversial. The principal aim is to undertake a meta-regression to determine whether moderator variables mediate the relationship between lidocaine and POCD. Areas covered: We searched the Web of Science, PubMed database, Scopus and the Cochrane Library database (up to June 2017) and systematically reviewed a list of retrieved articles. Our final review includes only randomized controlled trials (RCTs) that compared infusion of lidocaine and placebo during cardiopulmonary bypass (CPB). Mantel-Haenszel risk ratio (MH RR) and corresponding 95% confidence interval (CI) was used to report the overall effect and meta-regression analysis. A total of 688 patients in five RCTs were included. POCD occurred in 34% of all cases. Perioperative lidocaine reduces POCD (MH RR 0.702 (95% CI: 0.541-0.909). Younger age, male gender, longer CPB and higher concentration of lidocaine significantly mediate the relationship between lidocaine and POCD in favour of the neuroprotective effect of lidocaine. Expert commentary: The neuroprotective effect of lidocaine on POCD is consistent in spite of longer CPB time. A higher concentration of lidocaine strengthened the neuroprotective effect of lidocaine.

A HIGH-VELOCITY BULGE RR LYRAE VARIABLE ON A HALO-LIKE ORBIT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunder, Andrea; Storm, J.; Rich, R. M.

2015-07-20

We report on the RR Lyrae variable star, MACHO 176.18833.411, located toward the Galactic bulge and observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay, which has the unusual radial velocity of −372 ± 8 km s{sup −1} and true space velocity of −482 ± 22 km s{sup −1} relative to the Galactic rest frame. Located less than 1 kpc from the Galactic center and toward a field at (l, b) = (3, −2.5), this pulsating star has properties suggesting it belongs to the bulge RR Lyrae star population, yet a velocity indicating it is abnormal,more » at least with respect to bulge giants and red clump stars. We show that this star is most likely a halo interloper and therefore suggest that halo contamination is not insignificant when studying metal-poor stars found within the bulge area, even for stars within 1 kpc of the Galactic center. We discuss the possibility that MACHO 176.18833.411 is on the extreme edge of the bulge RR Lyrae radial velocity distribution, and also consider a more exotic scenario in which it is a runaway star moving through the Galaxy.« less

[Mother-child relationship and associated factors: Hierarchical analysis of the population base in a Brazilian state capital - BRISA Study].

PubMed

Cavalcante, Milady Cutrim Vieira; Lamy, Fernando; França, Ana Karina Teixeira da Cunha; Lamy, Zeni Carvalho

2017-05-01

Several factors can interfere in the mother-child relationship. Studies about different maternal characteristics and this relationship are scarce; they mainly evaluate women with psychopathology and use simultaneous regression models with adjustment for multiple confounders. This study aimed to assess factors associated with losses in the mother-child relationship through a cohort of 3,215 mothers of children between 15 and 36 months of age. Losses in the mother-child relationship, assessed by the Postpartum Bonding Questionnaire, was the outcome variable and the explanatory variables were demographic, socioeconomic, reproductive health and mental health of mothers as well as the conditions of the birth of children. It used multivariate regression analysis with a hierarchical approach in which the hierarchical blocks were structured according to the influence on the mother-child relationship. The prevalence of losses in the mother-child relationship was high (12.6%) and associated risk factors to lower maternal education (RR = 1.64), having unplanned pregnancy (RR = 1.42), consumption of alcoholic beverages during pregnancy (RR = 1.42) and maternal stress symptoms (RR = 1.88) and depression (RR = 2.00). Education and elements related to mental health were risks for damage in the mother-child relationship.

PRISMA--efficacy and safety of vedolizumab for inflammatory bowel diseases: a systematic review and meta-analysis of randomized controlled trials.

PubMed

Wang, Man Cai; Zhang, Ling Yi; Han, Wei; Shao, Yuan; Chen, Mo; Ni, Rui; Wang, Gen Nian; Wei, Feng Xian; Zhang, Ya Wu; Xu, Xiao Dong; Zhang, You Cheng

2014-12-01

Vedolizumab is an anti-inflammatory monoclonal antibody that exclusively targets the α4β7 integrin. We aimed to systematically review the efficacy and safety of vedolizumab for patients with inflammatory bowel diseases (IBDs). PubMed, EMBASE, and the Cochrane Library were searched up to May 2014. Randomized controlled trials examining the efficacy or safety of vedolizumab in patients with IBDs were eligible for inclusion. Data were extracted independently by 2 investigators and pooled using Review Manager 5.0 software (The Cochrane Collaboration, Copenhagen). Results were expressed as the relative risk (RR) with 95% confidence intervals (CIs). Six randomized controlled trials involving 2815 patients were eligible for inclusion. Vedolizumab was more effective than placebo for patients with ulcerative colitis and Crohn disease (CD) in clinical response (RR=1.82, 95% CI, [1.43, 2.31]; RR=1.46, 95% CI [1.18,1.81]) and clinical remission (RR=2.23, 95% CI [1.35, 3.68]; RR=1.71, 95% CI [1.25, 2.34]) during induction therapy. A superior effect was found during maintenance therapy in durable clinical/CD Activity Index-100 response (RR=2.22, 95% CI [1.62, 3.05]; RR=1.48, 95% CI [1.13, 1.94]) and clinical remission (RR=2.55, 95% CI [1.38, 4.70]; RR=1.15, 95% CI [0.75, 1.77]). However, vedolizumab may be associated with serious adverse events (RR=1.25, 95% CI [1.03, 1.52]) and nasopharyngitis (RR=1.56, 95% CI [1.08, 2.25]) for patients with CD. Vedolizumab was more effective than placebo as induction and maintenance therapy for IBDs, with an acceptable short-term safety profile, and achieving cure, although it may be associated with serious adverse events and nasopharyngitis for patients with CD.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ordoñez, Antonio J.; Sarajedini, Ata; Yang, Soung-Chul, E-mail: a.ordonez@ufl.edu, E-mail: ata@astro.ufl.edu, E-mail: sczoo@kasi.re.kr

We present the first detailed study of the RR Lyrae variable population in the Local Group dSph/dIrr transition galaxy, Phoenix, using previously obtained HST/WFPC2 observations of the galaxy. We utilize template light curve fitting routines to obtain best fit light curves for RR Lyrae variables in Phoenix. Our technique has identified 78 highly probable RR Lyrae stars (54 ab-type; 24 c-type) with about 40 additional candidates. We find mean periods for the two populations of (P {sub ab}) = 0.60 ± 0.03 days and (P{sub c} ) = 0.353 ± 0.002 days. We use the properties of these light curvesmore » to extract, among other things, a metallicity distribution function for ab-type RR Lyrae. Our analysis yields a mean metallicity of ([Fe/H]) = –1.68 ± 0.06 dex for the RRab stars. From the mean period and metallicity calculated from the ab-type RR Lyrae, we conclude that Phoenix is more likely of intermediate Oosterhoff type; however the morphology of the Bailey diagram for Phoenix RR Lyraes appears similar to that of an Oosterhoff type I system. Using the RRab stars, we also study the chemical enrichment law for Phoenix. We find that our metallicity distribution is reasonably well fitted by a closed-box model. The parameters of this model are compatible with the findings of Hidalgo et al., further supporting the idea that Phoenix appears to have been chemically enriched as a closed-box-like system during the early stage of its formation and evolution.« less

Tea consumption and the risk of ovarian cancer: A meta-analysis of epidemiological studies.

PubMed

Zhan, Xin; Wang, Jie; Pan, Shufen; Lu, Caijuan

2017-06-06

A large number of epidemiological studies have provided conflicting results about the relationship between tea consumption and ovarian cancer. This study aimed to clarify the association between tea consumption and ovarian cancer. A literature search of the MEDICINE, Scopus, PubMed, and Web of Science databases was performed in April 2016. A total of 18 (11 case-control and 7 cohort) studies, representing data for 701,857 female subjects including 8,683 ovarian cancer cases, were included in the meta-analysis. A random-effects meta-analysis was used to compute the pooled relative risks (RR), meta regression, and publication bias, and heterogeneity analyses were performed for the included trials. We found that tea consumption had a significant protective effect against ovarian cancer (relative risk [RR] = 0.86; 95% confidence interval [CI]: 0.76, 0.96). The relationship was confirmed particularly after adjusting for family history of cancer (RR = 0.85; 95% CI: 0.72, 0.97), menopause status (RR = 0.85; 95% CI: 0.72, 0.98), education (RR = 0.82; 95% CI: 0.68, 0.96), BMI (RR = 0.85; 95% CI: 0.70, 1.00) , smoking (RR = 0.83; 95% CI: 0.72, 0.93) and Jadad score of 3 (RR = 0.76; 95% CI: 0.56, 0.95) and 5 (RR = 0.74; 95% CI: 0.59, 0.89). The Begg's and Egger's tests (all P > 0.01) showed no evidence of publication bias. In conclusion, our meta-analysis showed an inverse association between tea consumption and ovarian cancer risk. High quality cohort-clinical trials should be conducted on different tea types and their relationship with ovarian cancer.

Automated classification of periodic variable stars detected by the wide-field infrared survey explorer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masci, Frank J.; Grillmair, Carl J.; Cutri, Roc M.

2014-07-01

We describe a methodology to classify periodic variable stars identified using photometric time-series measurements constructed from the Wide-field Infrared Survey Explorer (WISE) full-mission single-exposure Source Databases. This will assist in the future construction of a WISE Variable Source Database that assigns variables to specific science classes as constrained by the WISE observing cadence with statistically meaningful classification probabilities. We have analyzed the WISE light curves of 8273 variable stars identified in previous optical variability surveys (MACHO, GCVS, and ASAS) and show that Fourier decomposition techniques can be extended into the mid-IR to assist with their classification. Combined with other periodicmore » light-curve features, this sample is then used to train a machine-learned classifier based on the random forest (RF) method. Consistent with previous classification studies of variable stars in general, the RF machine-learned classifier is superior to other methods in terms of accuracy, robustness against outliers, and relative immunity to features that carry little or redundant class information. For the three most common classes identified by WISE: Algols, RR Lyrae, and W Ursae Majoris type variables, we obtain classification efficiencies of 80.7%, 82.7%, and 84.5% respectively using cross-validation analyses, with 95% confidence intervals of approximately ±2%. These accuracies are achieved at purity (or reliability) levels of 88.5%, 96.2%, and 87.8% respectively, similar to that achieved in previous automated classification studies of periodic variable stars.« less

Growth performance, carcass and noncarcass traits and meat quality of Barbarine lambs fed rosemary distillation residues.

PubMed

Yagoubi, Y; Hajji, H; Smeti, S; Mahouachi, M; Kamoun, M; Atti, N

2018-02-15

The aim of this experiment was to study the effect of total replacement of oat hay by rosemary distillation residues (RR) on growth, carcass characteristics and meat quality of Barbarine lambs. A total of 21 lambs were divided into three groups. The control group (C) was offered 600 g of oat hay; the RR87 and RR60 groups received 600 g of pellets containing 87% and 60% of RR, respectively. The CP content was 9% and 14% for RR87 and RR60, respectively. All animals were supplemented by 600 g of concentrate. After 77 days of fattening, lambs were slaughtered. The DM and CP intakes were significantly increased with RR diets. The average daily gain was higher (P<0.001), while the feed conversion rate was lower for RR60 and RR87 than C group. The dressing percentage was similar for all groups. The tissular (muscle, fat and bone) and the regional (leg, shoulder, etc.) carcass composition did not differ among groups. The bony organs and gut weights were similar among groups, while functional ones (skin, liver, kidney and testicles) were significantly heavier for both RR groups than control. The ultimate pH, water cooking loss and color variables were similar among groups and the chemical composition (protein, fat, myoglobin, collagen and iron) did not differ also among groups. These results revealed the opportunity of RR use in fattening lambs without adverse effects on carcass and meat characteristics. Moreover, 9% CP in RR pellets are enough given the same growth performance recorded as that of RR with 14% CP.

Citrus fruit intake and bladder cancer risk: a meta-analysis of observational studies.

PubMed

Liang, Sudong; Lv, Gaofei; Chen, Weikai; Jiang, Jianxin; Wang, Jingqun

2014-11-01

Epidemiological studies have investigated the association between citrus fruit and bladder cancer risk; however, the results are inconsistent. To assess these issues, we conducted a meta-analysis of currently available studies. We identified relevant articles by searching the MEDLINE and EMBASE databases. We calculated the summary relative risk (RR) with 95% confidence interval (95% CI) using a random effect model. We included eight case-control studies and six cohort studies in the meta-analysis. There was a significant inverse association between citrus fruit intake and bladder cancer risk in all pooled studies (RR: 0.85; 95% CI, 0.76-0.94) and case-control studies (RR: 0.77; 95% CI, 0.64-0.92), but not in the cohort studies (RR: 0.96; 95% CI, 0.87-1.07). Our results suggest that citrus fruit intake is related to decreased bladder cancer risk. Subsequent well-designed, large prospective studies are needed to obtain better understanding of this relationship.

Perioperative ketorolac increases post-tonsillectomy hemorrhage in adults but not children.

PubMed

Chan, Dylan K; Parikh, Sanjay R

2014-08-01

To evaluate the risk of post-tonsillectomy hemorrhage associated with perioperative ketorolac use. Systematic review and meta-analysis of primary articles reporting individual-level post-tonsillectomy hemorrhage rates in subjects receiving perioperative ketorolac and matched controls. Retrospective and prospective studies were both included. PubMed search was performed for "[ketorolac OR toradol] AND tonsillectomy." Articles fulfilling inclusion criteria were subjected to meta-analysis to determine summary relative risk (RR). Adults are at five times increased risk for post-tonsillectomy hemorrhage with ketorolac use (RR: 5.64; 95% confidence interval [CI]: 2.08-15.27; P < .001). In contrast, children under 18 are not at statistically significantly increased risk (RR: 1.39; 95% CI: 0.84-2.30; P = .20). Both retrospective and prospective studies yield consistent findings. There is no association of RR with pre- or postoperative administration of ketorolac. Ketorolac can be used safely in children, but is associated with a five-fold increased bleeding risk in adults. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

The Selection of RR Lyrae Stars Using POSS and SDSS

NASA Astrophysics Data System (ADS)

Fraser, Oliver J.; Barton, J. R.; Oldfield, B. J.; Biesiadzinski, T. P.; Horning, D. A.; Baerny, J. K.; Kiuchi, F.; Krogsrud, D.; Longhurst, D. S.; McCommas, L. P.; Scheidt, J. A.; Covarrubias, R.; Covey, K.; Laws, C.; Sesar, B.; Ivezic, Z.

2006-12-01

We test a method for identifying candidate RR Lyrae stars based on a comparison of POSS and SDSS photometry (Sesar et. al. 2005). Our candidate stars range in SDSS g magnitude from 14.4--16, or a distance of 6--12 kpc. Follow-up photometry obtained at Manastash Ridge Observatory typically includes 30-40 points per light curve. We find that at least two thirds of our sample of 23 objects are clearly variable, with light curves consistent with RR Lyrae. Candidate RR Lyrae were selected using stars that had brightened at least 0.3 magnitudes between POSS and SDSS, and which had SDSS magnitudes and colors consistent with the cuts in Ivezic et al. 2004.

[Sedentariness and absenteeism in the work setting].

PubMed

Martínez-López, Elkin; Saldarriaga-Franco, Juan

2008-01-01

To study the absenteeism in regard to sex, age and physical inactivity in the work setting. Frequency, duration, cost and causes of absenteeism are studied in relation physical activity as a regular behaviour. Relative risk and its 95 % confidence intervals are estimated. Respiratory diseases are the first cause of sick leaves. Absenteeism is higher in women. RR 1 ,65 (CI 95 % 1,53-1,77), is associated to age RR 1,25 (CI 95% 1,12-1,38) and to sedentariness RR 2,17 (IC 95 % 1,72-2,73). Physical inactivity increases the rate and duration of absenteeism This fact has unfavourable implications for all: the worker, the institution and the society.Programs aimed at promoting physical activity in the work setting are strategic options in occupational health.

Heart rate variability in workers of various professions in contrasting seasons of the year.

PubMed

Markov, Alexander; Solonin, Iuriy; Bojko, Evgeniy

2016-01-01

It is known that professional occupation affects the heart rate variability (HRV). However, most studies have not taken into account seasonal features of the HRV. The aim of this study has been to evaluate the HRV differences in winter and in summer in the case of the Ministry of the Russian Federation for Civil Defense, Emergencies and Elimination of Consequences of Natural Disasters (EMERCOM) workers and scientific workers from the Komi Science Center of the Ural Branch of the Russian Academy of Sciences. The short-term HRV was examined for 13 EMERCOM workers and 13 scientific workers. The data was collected in winter (December) and summer (July) for the same groups of workers. The time domain and frequency domain HRV analyses were performed. The EMERCOM workers had more contact with the external environment than the scientific workers. The two-way analysis of variance with repeated observations on a single factor has shown that "Season" and interaction of two factors "Season" and "Profession" significantly influenced the HRV among volunteers. The "Profession" factor did not influence the HRV parameters (except for the heart rate in winter, p = 0.042). Seasonal changes in the HRV parameters were not significant in the case of scientific workers. In contrast, the EMERCOM workers showed significantly decreased parameters of parasympathetic activity (the root-mean-square of successive differences in RR intervals, percentage of consecutive RR intervals differing by > 50 ms and the relative value high frequency power, p = 0.001, p = 0.014 and p = 0.009, respectively) and increased parameters of sympathetic activity (the stress index and ratio of low-frequency power to high-frequency power, p = 0.012 and p = 0.006, respectively) in winter as compared to summer. The results of our study indicate that, unlike the scientific workers, the EMERCOM workers showed significant changes in the HRV in contrasting seasons (winter and summer). A season of a year should be considered when assessing the HRV among workers of various professions. Int J Occup Med Environ Health 2016;29(5):793-800. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Dietary sodium influences the effect of mental stress on heart rate variability: a randomized trial in healthy adults.

PubMed

Allen, Alexander R; Gullixson, Leah R; Wolhart, Sarah C; Kost, Susan L; Schroeder, Darrell R; Eisenach, John H

2014-02-01

Dietary sodium influences intermediate physiological traits in healthy adults independent of changes in blood pressure. The purpose of this study was to test the hypothesis that dietary sodium affects cardiac autonomic modulation during mental stress. In a prospective, randomized cross-over design separated by 1 month between diets, 70 normotensive healthy young adults (F/M: 44/26, aged 18-38 years) consumed a 5-day low (10 mmol/day), normal (150 mmol), and high (400 mmol) sodium diet followed by heart rate variability (HRV) recordings at rest and during 5-min computerized mental arithmetic. Women were studied in the low hormone phase of the menstrual cycle following each diet. Diet did not affect resting blood pressure, but heart rate (HR) (mean ± SE) was 66 ± 1, 64 ± 1, and 63 ± 1 bpm in low, normal, and high sodium conditions, respectively (analysis of variance P = 0.02). For HRV, there was a main effect of sodium on resting SD of normalized RR intervals (SDNN), square root of the mean squared difference of successive normalized RR intervals (RMSSD), high frequency, low-frequency normalized units (LFnu), and high-frequency normalized units (HFnu) (P < 0.01 for all). The response to low sodium was most marked and consistent with sympathetic activation and reduced vagal activity, with increased LFnu and decreased SDNN, RMSSD, and HFnu compared to both normal and high sodium conditions (P ≤0.05 for all). Dietary sodium-by-mental stress interactions were significant for mean NN, RMSSD, high-frequency power, LFnu, and low frequency/high frequency ratio (P < 0.05 for all). The interactions signify that sodium restriction evoked an increase in resting sympathetic activity and reduced vagal activity to the extent that mental stress caused modest additional disruptions in autonomic balance. Conversely, normal and high sodium evoked a reduction in resting sympathetic activity and incremental increase in resting vagal activity, which were disrupted to a greater extent during mental stress compared to low sodium. We conclude that autonomic control of HRV at rest and during mental stress is altered by dietary sodium in healthy normotensive young adult men and women.

Computerized system for assessing heart rate variability.

PubMed

Frigy, A; Incze, A; Brânzaniuc, E; Cotoi, S

1996-01-01

The principal theoretical, methodological and clinical aspects of heart rate variability (HRV) analysis are reviewed. This method has been developed over the last 10 years as a useful noninvasive method of measuring the activity of the autonomic nervous system. The main components and the functioning of the computerized rhythm-analyzer system developed by our team are presented. The system is able to perform short-term (maximum 20 minutes) time domain HRV analysis and statistical analysis of the ventricular rate in any rhythm, particularly in atrial fibrillation. The performances of our system are demonstrated by using the graphics (RR histograms, delta RR histograms, RR scattergrams) and the statistical parameters resulted from the processing of three ECG recordings. These recordings are obtained from a normal subject, from a patient with advanced heart failure, and from a patient with atrial fibrillation.

Number of siblings and the risk of solid tumours: a nation-wide study

PubMed Central

Altieri, A; Hemminki, K

2007-01-01

We analysed the effects of number of siblings on the risk of solid tumours using the Swedish Family-Cancer Database, including population-based information on over 11 million individuals and more than 178 000 cancer patients diagnosed between 1958 and 2004. Incidence rate ratios (RRs), estimated by Poisson regression models, were adjusted for age, sex, birth cohort, area of residence and socioeconomic status. Having eight or more siblings vs none increased the risk of stomach cancer (RR=1.83, 95% confidence interval (CI), 1.44–2.34). Anal cancer diagnosed before age 40 showed the strongest association with the total siblings (RR=3.27, 95% CI, 2.04–5.26 for five or more siblings vs none). Endometrial (RR=0.76, 95% CI, 0.70–0.82), testicular (RR=0.71, 95% CI, 0.62–0.82), skin cancer (RR=0.82, 95% CI, 0.69–0.97) and melanoma (RR=0.72, 95% CI, 0.65–0.79) showed strong decreased risks for five or more siblings vs none. Prostate cancer risk for those with five or more older siblings vs none was 1.38 (95% CI, 1.23–1.55). Having five or more younger siblings was most strongly associated with stomach cancer (RR=1.59, 95% CI, 1.29–1.95) and melanoma (RR=0.68, 95% CI, 0.59–0.79). We conclude that sibship characteristics are strong correlates of cancer risk at several sites; plausible interpretations include socioeconomic status. PMID:17453006

Indications of caesarean section in overweight and obese versus normal-weight pregnant women: a retrospective cohort study.

PubMed

Fernández Alba, Juan Jesús; Paublete Herrera, Carmen; Vilar Sanchez, Angel; Gonzalez-Macias, Carmen; Castillo Lara, Maria; Torrejón, Rafael; Moreno Corral, Luis Javier

2018-02-01

The aim of this study was to test the hypothesis that indications of c-section in overweight or obese pregnant women are different from those with normal-weight. Retrospective cohort study at University Hospital of Puerto Real (Cádiz-Spain). We compared frequency distribution of c-section indications in overweight and obese versus normal-weight. The risk of c-section by different indications was calculated as relative risk. A total of 4685 births were included in the study. There are significant differences in the frequency distribution of caesarean indications among normal weight and overweight or obese women. In overweight, we found an increased risk of c-section due to previous c-section (RR: 1.73; confidence interval [CI] 95% 1.24-2.42), obstructed/non-progressive labour (RR: 1.34; CI 95% 1.03-1.75), failed induction of labour (RR: 2.38; CI 95% 1.30-4.34) and foetal distress (RR: 1.73; CI 95% 1.21-2.49). This risk was even higher in obese women: previous c-section (RR: 3.25; CI 95% 2.24-4.71), obstructed/non-progressive labour (RR: 2; CI 95% 1.45-2.77), failed induction (RR: 2.52; CI 95% 1.15-5.51) and foetal distress (RR: 2.35; CI 95% 1.51-3.65). The risk of caesarean section due to previous caesarean section, obstructed/non-progressive labour, failed induction of labour or foetal distress is greater in overweight and obese than in normal-weight. This increase in risk also increases progressively as maternal BMI increases.

[Public hospital utilization by the foreign population in Aragon, Spain (2004-2007)].

PubMed

Ben Cheikh, Wafa; Abad, José María; Arribas, Federico; Andrés, Eva; Rabanaque, María José

2011-01-01

To describe hospitalization rates and hospital morbidity among the foreign population residing in Aragon (Spain) by country of birth, between 2004 and 2007, and to compare these rates with those in the autochthonous population. A retrospective longitudinal study was carried out of hospital discharges of the foreign population in public hospitals in Aragon. Utilization rates were estimated by sex, age, country of birth and main diagnosis. Poisson regression was used to estimate the utilization rate ratios and their 95% confidence intervals. Hospitalization rates were lower in the foreign population (adjusted RR: 0.52; 95% CI: 0.51-0.56), except in women aged between 15 and 24 years (RR: 2.9; 95% CI: 2.8-3.0) and among those born in the Maghreb (RR: 1.8; 95% CI: 1.7; 1.9), sub-Saharan Africa (RR: 2.0; 95% CI: 1.9-2.1) and Asia (RR=1.4; 95% CI: 1.3-1.6). When hospital discharges related to obstetrics and gynecology were excluded, only women born in sub-Saharan Africa continued to have adjusted RR greater than 1. These women had higher hospitalization rates in groups of infectious and parasitic diseases (RR: 2.5) and blood and blood-forming organs (RR: 2.8). In Aragon (Spain), public hospital utilization is lower in foreigners than in the autochthonous population. The diseases treated varied by country of birth. The diseases prevalent in these countries, together with hereditary diseases, can increase hospital utilization rates. Copyright © 2010 SESPAS. Published by Elsevier Espana. All rights reserved.

Identifying Occupations at Risk for Laryngeal Disorders Requiring Specialty Voice Care.

PubMed

Mori, Matthew C; Francis, David O; Song, Phillip C

2017-10-01

Objective To identify occupational groups' use of specialty voice clinic evaluation. Study Design Retrospective cohort study. Setting Tertiary subspecialty clinic. Subjects and Methods We analyzed data collected on patients presenting to the Massachusetts Eye and Ear Infirmary Voice and Speech Laboratory over a 20-year period (1993-2013). The relative risk (RR) and 99% confidence interval (CI) of presentation were calculated for each occupational category in the greater Boston population using year-matched data from the Bureau of Labor Statistics (BLS). Results The records of 12,120 new patients were reviewed. Using year- and occupation-matched BLS data from 2005 to 2013, 2726 patients were included in the cohort analysis. Several occupations had significantly higher risk of presentation. These included arts and entertainment (RR 4.98, CI 4.18-5.95), law (RR 3.24, CI 2.48-4.23), education (RR 3.08, CI 2.70-3.52), and social services (RR 2.07, CI 1.57-2.73). In contrast, many occupations had significantly reduced risk of presentation for laryngological disorders, for example, maintenance (RR 0.25, CI 0.15-0.42), food preparation (RR 0.35, CI 0.26-0.48), and administrative support (RR 0.49, CI 0.41-0.57). Conclusion Certain occupations are associated with higher use of laryngological services presumably because of their vocational voice needs. In addition to confirming findings from other studies, we identified several new occupation groups with increased or decreased risk for laryngologic disorders. Understanding what factors predispose to requiring specialty voice evaluation may help in targeting preventative efforts.

[Diabetes mellitus as a risk factor for dementia in the Mexican elder population].

PubMed

Mejía-Arango, Silvia; Zúñiga-Gil, Clemente

2011-10-01

Diabetes and dementia are growing problems throughout the world and especially in developing countries. To determine the risk of developing dementia in subjects with type 2 diabetes mellitus. Diabetic elders free of dementia from the Mexican Health and Aging study, a prospective community-based cohort research were followed after two years. Socio-demographic factors, comorbid conditions and type of diabetes treatment were analyzed in subjects who become demented. At baseline, 749 participants (13.8%) had diabetes mellitus. During the follow-up period (mean: 2.02 years; range: 1-3 years), 306 of 749 persons with diabetes mellitus developed dementia, yielding a relative risk (RR) of 2.08 (95% confidence interval, 95% CI = 1.59-2.73). The effect was strongest in persons aged 80 years or older with a RR of 2.44 (95% CI = 1.46-4.08), men had a greater relative risk than women (RR = 2.25; 95% CI = 1.46-3.49 vs. RR = 1.98; 95% CI = 1.08-1.11) and subjects with low education (< 7 years of schooling) had a significant RR while those with higher education didn't. Individuals treated with insulin where at highest risk of dementia (RR = 2.83; 95% CI = 1.58-5.06). Hypertension (RR = 2.75; 95% CI = 1.86-4.06) and depression (RR = 3.78; 95% CI = 2.37-6.04) where the two comorbidities which increased the risk of dementia. Subjects with diabetes mellitus have an increased risk of developing dementia. Sociodemographic factors and other co-morbidities highly prevalent in the Mexican population contribute to the diabetes-dementia association.

Before the Bar: Kinematic Detection of a Spheroidal Metal-poor Bulge Component

NASA Astrophysics Data System (ADS)

Kunder, Andrea; Rich, R. M.; Koch, A.; Storm, J.; Nataf, D. M.; De Propris, R.; Walker, A. R.; Bono, G.; Johnson, C. I.; Shen, Juntai; Li, Z.-Y.

2016-04-01

We present 947 radial velocities of RR Lyrae variable stars in four fields located toward the Galactic bulge, observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay (BRAVA-RR). We show that these RR Lyrae stars (RRLs) exhibit hot kinematics and null or negligible rotation and are therefore members of a separate population from the bar/pseudobulge that currently dominates the mass and luminosity of the inner Galaxy. Our RRLs predate these structures and have metallicities, kinematics, and spatial distribution that are consistent with a “classical” bulge, although we cannot yet completely rule out the possibility that they are the metal-poor tail of a more metal-rich ([{Fe}/{{H}}]˜ -1 dex) halo-bulge population. The complete catalog of radial velocities for the BRAVA-RR stars is also published electronically.

Stress management at the worksite: reversal of symptoms profile and cardiovascular dysregulation.

PubMed

Lucini, Daniela; Riva, Silvano; Pizzinelli, Paolo; Pagani, Massimo

2007-02-01

Work stress may increase cardiovascular risk either indirectly, by inducing unhealthy life styles, or directly, by affecting the autonomic nervous system and arterial pressure. We hypothesized that, before any apparent sign of disease, work-related stress is already accompanied by alterations of RR variability profile and that a simple onsite stress management program based on cognitive restructuring and relaxation training could reduce the level of stress symptoms, revert stress-related autonomic nervous system dysregulation, and lower arterial pressure. We compared 91 white-collar workers, enrolled at a time of work downsizing (hence, in a stress condition), with 79 healthy control subjects. Psychological profiles were assessed by questionnaires and autonomic nervous system regulation by spectral analysis of RR variability. We also tested a simple onsite stress management program (cognitive restructuring and relaxation training) in a subgroup of workers compared with a sham subgroup (sham program). Workers presented an elevated level of stress-related symptoms and an altered variability profile as compared with control subjects (low-frequency component of RR variability was, respectively, 65.2+/-2 versus 55.3+/-2 normalized units; P<0.001; opposite changes were observed for the high-frequency component). These alterations were largely reverted (low-frequency component of RR variability from 63.6+/-3.9 to 49.3+/-3 normalized units; P<0.001) by the stress management program, which also slightly lowered systolic arterial pressure. No changes were observed in the sham program group. This noninvasive study indicates that work stress is associated with unpleasant symptoms and with an altered autonomic profile and suggests that a stress management program could be implemented at the worksite, with possible preventive advantages for hypertension.

The epidemiology of hepatitis A in Rio de Janeiro: environmental and domestic risk factors.

PubMed Central

Almeida, L. M.; Werneck, G. L.; Cairncross, S.; Coeli, C. M.; Costa, M. C.; Coletty, P. E.

2001-01-01

A serological study of hepatitis A was carried out in low-income areas scheduled for a major sanitation programme in Rio de Janeiro, Brazil. Blood spots were collected by finger puncture and transported on filter paper, and total antibodies to hepatitis A virus were detected by ELISA. Households were also interviewed to collect information on their environmental conditions and socio-economic status. A generalized linear model using a complementary log-log function was fitted to the data, using the logarithm of age as an explanatory variable to derive adjusted rate ratios (RR). The risk of infection was greater among households with 2-3 members per room (RR = 1.4; 95% CI = 1.04-1.8) or more than three per room (RR = 1.5; 95% CI = 1.2-2.0). People living on hilltops (RR = 1.5; 95% CI = 1.02-2.2), near to open sewers (RR = 1.2; 95% CI = 1.03-1.5) or lacking a kitchen (RR = 1.4; 95% CI = 1.08-1.9) were also at greater risk than others. The number of taps and water-using fittings in the house was associated with a protective effect (RR = 0.9 for each tap; 95% CI = 0.9-0.98). A significant protective association was found with maternal education but not with gender or household income. The results do not suggest a strong association with water quality. Ownership of a ceramic water filter was associated with a protective effect on the margin of significance, but the practice of boiling drinking-water was not, nor was the type of water source used. The results suggest that that the risk of infection with hepatitis A is determined by environmental variables in the domestic and public domains. PMID:11693510

Genetic influences on heart rate variability

PubMed Central

Golosheykin, Simon; Grant, Julia D.; Novak, Olga V.; Heath, Andrew C.; Anokhin, Andrey P.

2016-01-01

Heart rate variability (HRV) is the variation of cardiac inter-beat intervals over time resulting largely from the interplay between the sympathetic and parasympathetic branches of the autonomic nervous system. Individual differences in HRV are associated with emotion regulation, personality, psychopathology, cardiovascular health, and mortality. Previous studies have shown significant heritability of HRV measures. Here we extend genetic research on HRV by investigating sex differences in genetic underpinnings of HRV, the degree of genetic overlap among different measurement domains of HRV, and phenotypic and genetic relationships between HRV and the resting heart rate (HR). We performed electrocardiogram (ECG) recordings in a large population-representative sample of young adult twins (n = 1060 individuals) and computed HRV measures from three domains: time, frequency, and nonlinear dynamics. Genetic and environmental influences on HRV measures were estimated using linear structural equation modeling of twin data. The results showed that variability of HRV and HR measures can be accounted for by additive genetic and non-shared environmental influences (AE model), with no evidence for significant shared environmental effects. Heritability estimates ranged from 47 to 64%, with little difference across HRV measurement domains. Genetic influences did not differ between genders for most variables except the square root of the mean squared differences between successive R-R intervals (RMSSD, higher heritability in males) and the ratio of low to high frequency power (LF/HF, distinct genetic factors operating in males and females). The results indicate high phenotypic and especially genetic correlations between HRV measures from different domains, suggesting that >90% of genetic influences are shared across measures. Finally, about 40% of genetic variance in HRV was shared with HR. In conclusion, both HR and HRV measures are highly heritable traits in the general population of young adults, with high degree of genetic overlap across different measurement domains. PMID:27114045

Discovering Cepheid and RR Lyrae Stars: Pan-STARRS Science Archive @ STScI and Robotically Controlled Telescopes

NASA Astrophysics Data System (ADS)

Johnson, Elizabeth; Strolger, Louis-Gregory; Engle, Scott G.; Anderson, Richard I.; Rest, Armin; Calamida, Annalisa; Dosovitz Fox, Ori; Laney, David

2017-01-01

Cepheid and RR Lyrae stars are an integral part of the cosmic distance ladder and are also useful for studying galactic structure and stellar ages. This project aims to greatly expand the number of known periodic variables in our galaxy by identifying candidates in the PanSTARRS-1 3pi catalog, and carrying out systematically targeted characterization with robotically controlled telescopes. Candidate targets are selected from available detection tables based on color and variability indices and are then fully vetted using robotic telescopes: the RCT 1.3 meter (Kitt Peak National Observatory) and RATIR 1.5 meter (Mexico). Here we present work to develop a full, semi-automated prescription for candidate selection, targeted follow-up photometry, cataloging, and classification, which allows the review of approximately 25 variable candidates every two weeks. We make comparisons of our sample selection and purity from a similar study based on Pan-STARRS data (Hernitschek et al. 2016), as well as candidates identified in Gaia DR1. The goal, through continued observation and analysis, is to identify at least 10,000 new variables, hundreds of which will be new Cepheid and RR Lyrae stars.

A NEW CENSUS OF THE VARIABLE STAR POPULATION IN THE GLOBULAR CLUSTER NGC 2419

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Criscienzo, M.; Greco, C.; Ripepi, V.

We present B, V, and I CCD light curves for 101 variable stars belonging to the globular cluster NGC 2419, 60 of which are new discoveries, based on data sets obtained at the Telescopio Nazionale Galileo, the Subaru telescope, and the Hubble Space Telescope. The sample includes 75 RR Lyrae stars (38 RRab, 36 RRc, and one RRd), one Population II Cepheid, 12 SX Phoenicis variables, two {delta} Scuti stars, three binary systems, five long-period variables, and three variables of uncertain classification. The pulsation properties of the RR Lyrae variables are close to those of Oosterhoff type II clusters, consistentmore » with the low metal abundance and the cluster horizontal branch morphology, disfavoring (but not totally ruling out) an extragalactic hypothesis for the origin of NGC 2419. The observed properties of RR Lyrae and SX Phoenicis stars are used to estimate the cluster reddening and distance, using a number of different methods. Our final value is {mu}{sub 0} (NGC 2419) = 19.71 {+-} 0.08 mag (D = 87.5 {+-} 3.3 kpc), with E(B - V) = 0.08 {+-} 0.01 mag, [Fe/H] = -2.1 dex on the Zinn and West metallicity scale, and a value of M{sub V} that sets {mu}{sub 0} (LMC) = 18.52 mag. This value is in good agreement with the most recent literature estimates of the distance to NGC 2419.« less

A metronome for pacing manual ventilation in a neonatal resuscitation simulation.

PubMed

Cocucci, Cecilia; Madorno, Matías; Aguilar, Adriana; Acha, Leila; Szyld, Edgardo; Musante, Gabriel

2015-01-01

During manual positive pressure ventilation (PPV), delivering a recommended respiratory rate (RR) is operator dependent. We tested the efficacy of a metronome as a standardised method to improve the accuracy of delivered RR during manual PPV in a neonatal resuscitation simulation. We conducted a blinded simulation in two consecutive stages. Using a self-inflating bag, 36 CPR trained operators provided PPV to a modified neonatal manikin via an endotracheal tube. Pressure and flow signals were captured by a respiratory function monitor. In the first standard stage, participants delivered RR as they would in delivery room. Prior to the second stage, they were asked about what their target RR had been and a metronome was set to that target. Subsequently, operators repeated PPV attempting to coordinate their delivered RR with the metronome. To evaluate accuracy we generated the variable RR Gap as the absolute difference between delivered and target RR. The primary outcome was the difference in RR Gap between stages. Mean (SD) target RR was 50 (8.7) inflations/min. During the initial stage, median (IQR) RR Gap was 11.6 (4.7-18.3) inflations/min and 20/36 participants (55.5%) had a mean delivered RR beyond the recommended range. When paced by the metronome, RR Gap was reduced to 0.2 (0.1-0.4) inflations/min and 32/36 participants (89%) fell within the recommended range. The use of a metronome improved the accuracy of delivered RR during manual PPV. Novel approaches to deliver an accurate RR during manual PPV need to be tested in more realistic scenarios. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Impact of changing US cigarette smoking patterns on incident cancer: risks of 20 smoking-related cancers among the women and men of the NIH-AARP cohort

PubMed Central

Freedman, Neal D; Abnet, Christian C; Caporaso, Neil E; Fraumeni, Joseph F; Murphy, Gwen; Hartge, Patricia; Hollenbeck, Albert R; Park, Yikyung; Shiels, Meredith S; Silverman, Debra T

2016-01-01

Abstract Background: Historically, US women started smoking at a later age than men and had lower relative risks for smoking-related cancers. However, more recent birth cohorts of women and men have similar smoking histories and have now reached the high-risk age for cancer. The impact of these changes on cancer incidence has not been systematically examined. Methods: Relative risks (RR), 95% confidence intervals (CI) and attributable fractions were calculated for cigarette smoking and incidence of 20 smoking-related cancers in 186 057 women and 266 074 men of the National Institutes of Health-AARP cohort, aged 50 to 71 years in 1995 and followed for 11 years. Results: In the cohort, which included participants born between 1924 and 1945, most women and men started smoking as teenagers. RRs for current vs never smoking were similar in women and men for the following cancers: lung squamous-cell (RR women: 121.4, 95% CI: 57.3–257.4; RR men:114.6, 95% CI: 61.2–214.4), lung adenocarcinoma (RR women: 11.7, 95% CI: 9.8–14.0; RR men: 15.6, 95% CI: 12.5–19.6), laryngeal (RR women: 37.0, 95% CI: 14.9–92.3; RR men: 13.8, 95% CI: 9.3–20.2), oral cavity-pharyngeal (RR women:4.4, 95% CI: 3.3–6.0; RR men: 3.8, 95% CI: 3.0–4.7), oesophageal squamous cell (RR women: 7.3, 95% CI: 3.5–15.5; RR men: 6.2, 95% CI: 2.8–13.7), bladder (RR women: 4.7, 95% CI: 3.7–5.8; RR men: 4.0, 95% CI: 3.5–4.5), colon (RR women: 1.3, 95% CI: 1.2–1.5; RR men: 1.3, 95% CI: 1.1–1.4), and at other sites, with similar attributable fractions. Conclusions: RRs for current smoking and incidence of many smoking-related cancers are now similar in US women and men, likely reflecting converging smoking patterns. PMID:26411408

Anomalous double-mode RR Lyrae stars in the Magellanic Clouds

NASA Astrophysics Data System (ADS)

Soszyński, I.; Smolec, R.; Dziembowski, W. A.; Udalski, A.; Szymański, M. K.; Wyrzykowski, Ł.; Ulaczyk, K.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Skowron, D.; Skowron, J.; Mróz, P.; Pawlak, M.

2016-12-01

We report the discovery of a new subclass of double-mode RR Lyrae stars in the Large and Small Magellanic Clouds. The sample of 22 pulsating stars has been extracted from the latest edition of the Optical Gravitational Lensing Experiment collection of RR Lyrae variables in the Magellanic System. The stars pulsating simultaneously in the fundamental (F) and first-overtone (1O) modes have distinctly different properties than regular double-mode RR Lyrae variables (RRd stars). The P1O/PF period ratios of our anomalous RRd stars are within a range of 0.725-0.738, while `classical' double-mode RR Lyrae variables have period ratios in the range of 0.742-0.748. In contrast to the typical RRd stars, in the majority of the anomalous pulsators, the F-mode amplitudes are higher than the 1O-mode amplitudes. The light curves associated with the F-mode in the anomalous RRd stars show different morphology than the light curves of, both, regular RRd stars and single-mode RRab stars. Most of the anomalous double-mode stars show long-term modulations of the amplitudes (Blazhko-like effect). Translating the period ratios into the abundance parameter, Z, we find for our stars Z ∈ (0.002, 0.005) - an order of magnitude higher values than typical for RR Lyrae stars. The mass range of the RRd stars inferred from the WI versus PF diagram is (0.55-0.75) M⊙. These parameters cannot be accounted for with single star evolution assuming a Reimers-like mass-loss. Much greater mass-loss caused by interaction with other stars is postulated. We blame the peculiar pulsation properties of our stars to the parametric resonance instability of the 1O-mode to excitation of the F- and 2O-modes as with the inferred parameters of the stars 2ω1O ≈ ωF + ω2O.

Traveler's diarrhea at sea: three outbreaks of waterborne enterotoxigenic Escherichia coli on cruise ships.

PubMed

Daniels, N A; Neimann, J; Karpati, A; Parashar, U D; Greene, K D; Wells, J G; Srivastava, A; Tauxe, R V; Mintz, E D; Quick, R

2000-04-01

Enterotoxigenic Escherichia coli (ETEC) has become the leading bacterial cause of gastroenteritis outbreaks on cruise ships. Investigation of recent outbreaks of ETEC gastroenteritis on 3 cruise ships indicated that all were associated with consuming beverages with ice cubes on board the ship (relative risk [RR], 1.4, 95% confidence interval [CI], 1.0-1.9, P=.02; RR, 1.9, 95% CI, 1.3-2. 9, P<.001; and RR, 1.3, 95% CI, 1.0-1.6, P<.01), and 2 were associated with drinking unbottled water (RR, 2.7, 95% CI, 1.8-4.1, P<.001; RR, 1.7, 95% CI, 1.3-2.3, P<.001). Multiple ETEC serotypes were detected in patients' stool specimens in each of the 3 outbreaks, and 12 (38%) of 32 isolates were resistant to > or =3 antimicrobial agents. ETEC appears to be emerging as a waterborne pathogen on cruise ships. Water bunkered in overseas ports was the likely source of ETEC infection in these outbreaks. To ensure passenger safety, cruise ships that take on water in foreign ports must ensure that water treatment and monitoring systems function properly.

Coal home heating and environmental tobacco smoke in relation to lower respiratory illness in Czech children, from birth to 3 years of age

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, R.J.; Hert-Picciotto, I.; Dostal, M.

2006-07-15

The objective of this study was to evaluate how indoor pollution from tobacco and home heating may adversely affect respiratory health in young children. A total of 452 children born 1994-1996 in two districts in the Czech Republic participated. Lower respiratory illness (LRI) diagnoses occurred more frequently in children from homes heated by coal (vs. other energy sources or distant furnaces; rate ratio (RR) = 1.45; 95% confidence interval (CI), 1.07-1.97). Maternal prenatal smoking and other adult smokers also increased LRI rates (respectively: RR = 1.48; 95% CI, 1.10-2.01; and RR = 1.29; 95% CI, 1.01-1.65). Cooking fuels (primarily electricity,more » natural gas, or propane) were not associated with LRI incidence. For children never breast-fed, coal home heating and mother's smoking conferred substantially greater risks: RR = 2.77 (95% CI, 1.45-5.27) and RR = 2.52 (95% CI, 1.31-4.85), respectively. This maternal smoking and coal home heating increased risk for LRI in the first 3 years of life, particularly in children not breast-fed.« less

Neurological mortality among U.S. veterans of the Persian Gulf War: 13-year follow-up.

PubMed

Barth, Shannon K; Kang, Han K; Bullman, Tim A; Wallin, Mitchell T

2009-09-01

This study focuses on long-term mortality, specifically brain cancer, amyotrophic lateral sclerosis (ALS), Parkinson's disease, and multiple sclerosis (MS) of 621,902 veterans who served in the 1990-1991 Persian Gulf War (GW), and 746,248 non-GW veterans. Follow-up began with the date the veteran left the GW theater or May 1, 1991 and ended with the date of death or December 31, 2004. Cox proportional hazard models were used for analyses. Adjusted mortality rate ratios (aRR) of GW veterans compared to non-GW veterans were not statistically significant for brain cancer (aRR = 0.90, 95% confidence interval (CI): 0.73, 1.11), MS (aRR = 0.61, 95% CI: 0.23, 1.63), Parkinson's disease (aRR = 0.71, 95% CI: 0.17, 2.99), or ALS (aRR = 0.96, 95% CI: 0.56, 1.62). GW veterans potentially exposed to nerve agents for 2 or more days and GW veterans exposed to oil well fire smoke were at increased risk for brain cancer mortality (aRR = 2.71, 95% CI: 1.25, 5.87; aRR = 1.81, 95% CI: 1.00, 3.27; respectively). The risk of death due to ALS, MS, Parkinson's disease, and brain cancer was not associated with 1991 GW service in general. However, GW veterans potentially exposed to nerve agents at Khamisiyah, Iraq, and to oil well fire smoke had an increased risk of mortality due to brain cancer. (c) 2009 Wiley-Liss, Inc.

BARRIERS TO LIFE JACKET USE AMONG ADULT RECREATIONAL BOATERS

PubMed Central

Quistberg, D. Alex; Quan, Linda; Ebel, Beth E.; Bennett, Elizabeth E.; Mueller, Beth A.

2015-01-01

Objective To identify barriers to life jacket use. Design Cross-sectional survey. Setting Nine public boat ramps in western Washington State, USA, August-November, 2008. Participants 675 adult boaters (>18 years) on motor boats <26 feet long. Main outcome Low or no life jacket use (0–50% of time) versus high life jacket use (51–100% of time). Results Low/no life jacket use (0%–50% of time) was associated with longer boat length (per foot, risk ratio [RR] 1.03, 95% confidence interval [CI] 1.02–1.05), alcohol use (RR 1.11, 95% CI 1.01–1.20), perception of life jackets as “uncomfortable” (RR 1.29, 95%CI 1.09–1.52), perceived greater level of swimming ability (RR 1.25, 95% CI 1.03–1.53 for “expert swimmer”), and possibly with lack of confidence that a life jacket may save one from drowning (RR 1.13, 95%CI 0.96–1.32). Low life jacket use was less likely when a child was onboard (RR 0.88, 95% CI 0.79–0.99), or if the respondent had taken a boating safety class (RR 0.94, 95% CI 0.87–1.01). Conclusions Life jacket use may increase with more comfortable devices, such as inflatable life jackets, and with increased awareness of their efficacy in preventing drowning. Boater education classes may be associated with increased life jacket use among adults. PMID:24686261

A case-control study of gallstones: a major risk factor for biliary tract cancer.

PubMed

Kato, I; Kato, K; Akai, S; Tominaga, S

1990-01-01

Because of the strong association between gallstones and biliary tract cancer, we conducted a case-control study of gallstones at Niigata Cancer Center Hospital. Eighty-six cases with gallstones (33 males and 53 females) and 116 hospital controls (56 males and 60 females) were surveyed by means of a self-administered questionnaire. Gallstones were categorized into cholesterol stones (25 cases) and pigment stones (30 cases) based on the appearance of the stones. In multivariate analyses based on an unconditional logistic regression model, the risk of total gallstones was positively associated with a taste for salty food (relative risk (RR) = 2.31, 95% confidence interval (CI): 1.10-4.84), an intake of lettuce and cabbage (RR = 2.98, 95% CI: 1.47-6.06) and a family history of biliary diseases (RR = 5.63, 95% CI: 1.76-17.95), and inversely associated with an intake of salted and dried fish (RR = 0.16, 95% CI: 0.04-0.64). When analyzed by type of stones, cholesterol stones were associated with a taste for oily food (RR = 3.87, 95% CI: 1.36-11.03) and pigment stones were positively associated with professional or administrative occupation (RR = 4.74, 95% CI: 1.35-16.68) and inversely associated with a taste for less greasy food (RR = 0.28, 95% CI: 0.10-0.83). Some of these results are consistent with the results of our previous study on biliary tract cancer.

Health outcomes and family services in kinship care: analysis of a national sample of children in the child welfare system.

PubMed

Sakai, Christina; Lin, Hua; Flores, Glenn

2011-02-01

To comprehensively assess family services, health, and health care outcomes for US children in kinship care vs foster care. A 3-year prospective cohort study. National Survey of Child and Adolescent Well-Being. The sample consisted of 1308 US children entering out-of-home care following reported maltreatment. Kinship care vs foster care. Baseline caregivers' support services and the children's behavioral, mental health, and health service use outcomes 3 years after placement. Kinship caregivers were more likely than foster caregivers to have a low socioeconomic status but reported significantly fewer support services (caregiver subsidies, parent training, peer support, and respite care). Kinship care was associated with a lower risk ratio (RR) of continuing behavioral problems (RR = 0.59; 95% confidence interval [CI], 0.41-0.80), low social skills (RR = 0.61; 95% CI, 0.40-0.87), mental health therapy use (RR = 0.45; 95% CI, 0.27-0.73), and psychotropic medication use (RR = 0.46; 95% CI, 0.24-0.82) but higher risk of substance use (RR = 1.88; 95% CI, 0.92-3.20) and pregnancy (RR = 4.78; 95% CI, 1.07-17.11). Kinship caregivers received fewer support services than foster caregivers. Children in kinship care fared better with behavioral and social skills problems, mental health therapy use, and psychotropic medication use. Adolescents in kinship care may be at higher risk for substance use and pregnancy.

Post-cataract Surgery Endophthalmitis in the United States: Analysis of the Complete 2003–2004 Medicare Database of Cataract Surgeries

PubMed Central

Keay, Lisa; Gower, Emily W.; Cassard, Sandra D.; Tielsch, James M.; Schein, Oliver D.

2011-01-01

OBJECTIVE To estimate endophthalmitis incidence following cataract surgery nationally and at the state level in 2003–2004 and to explore risk factors. DESIGN Analysis of Medicare beneficiary claims data. PARTICIPANTS 100% sample of Medicare recipients’ claims for endophthalmitis and outpatient cataract surgery services. METHODS Cataract surgeries were identified by procedure codes and merged with demographic information. Cataract annual surgical volume was calculated for all surgeons. Presumed post-operative endophthalmitis cases were identified by International Classification of Diseases-9 Clinical Modification Codes (ICD-9-CM) on claims within 42 days after surgery. Endophthalmitis rates and 95% confidence intervals were calculated at state and national levels. Logistic regression was used to investigate the association between developing endophthalmitis and surgery location and surgeon factors. MAIN OUTCOME MEASURES Endophthalmitis incidence and risk factors. RESULTS 4,006 cases of presumed endophthalmitis occurred following 3,280,966 cataract surgeries. The national rate in 2003 was 1.33 per 1000 surgeries (95% confidence interval [CI]: 1.27–1.38) and decreased to 1.11 per 1000 (95% CI: 1.06–1.16) in 2004. Males (relative risk [RR] 1.23, 95% CI: 1.15–1.31), older individuals (RR 1.53, 95% CI 1.38–1.69; 85+ compared to 65–74 years), Blacks (RR 1.17, 95% CI 1.03–1.33) and Native Americans (RR 1.72, 95% CI 1.07–2.77) had increased risk of disease. After adjustment, surgeries by surgeons with low annual volume (RR 3.80, 95% CI 3.13–4.61 for 1–50 compared to 1001+annual surgeries) and less experience (RR 1.41, 95% CI 1.25–1.59 1–10 compared to 30+ years) and surgeries per formed in 2003 (RR 1.20, 95% CI 1.13–1.28) had increased endophthalmitis risk. CONCLUSIONS Endophthalmitis rates are lower than previous-year US estimates, but remain higher than rates reported from a series of studies from Sweden; patient factors or methodological differences may contribute to differences across countries. Patient age, gender and race, and surgeon volume and years of experience are important risk factors. PMID:22297029

Variable Stars in Large Magellanic Cloud Globular Clusters. II. NGC 1786

NASA Astrophysics Data System (ADS)

Kuehn, Charles A.; Smith, Horace A.; Catelan, Márcio; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

2012-12-01

This is the second in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to study how RR Lyrae stars in Oosterhoff-intermediate systems compare to their counterparts in Oosterhoff I/II systems. In this paper, we present the results of our new time-series B-V photometric study of the globular cluster NGC 1786. A total of 65 variable stars were identified in our field of view. These variables include 53 RR Lyraes (27 RRab, 18 RRc, and 8 RRd), 3 classical Cepheids, 1 Type II Cepheid, 1 Anomalous Cepheid, 2 eclipsing binaries, 3 Delta Scuti/SX Phoenicis variables, and 2 variables of undetermined type. Photometric parameters for these variables are presented. We present physical properties for some of the RR Lyrae stars, derived from Fourier analysis of their light curves. We discuss several different indicators of Oosterhoff type which indicate that the Oosterhoff classification of NGC 1786 is not as clear cut as what is seen in most globular clusters. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Meat Consumption, Heterocyclic Amines, and Colorectal Cancer Risk: The Multiethnic Cohort Study

PubMed Central

Ollberding, Nicholas J.; Wilkens, Lynne R.; Henderson, Brian E.; Kolonel, Laurence N.; Le Marchand, Loïc

2012-01-01

Greater consumption of red and processed meat has been associated with an increased risk of colorectal cancer in several recent meta-analyses. Heterocyclic amines (HCAs) have been hypothesized to underlie this association. In this prospective analysis conducted within the Multiethnic Cohort Study, we examined whether greater consumption of total, red, or processed meat was associated with the risk of colorectal cancer among 165,717 participants who completed a detailed food frequency questionnaire at baseline. In addition, we examined whether greater estimated intake of HCAs was associated with the risk of colorectal cancer among 131,763 participants who completed a follow-up questionnaire that included a meat-cooking module. A total of 3,404 and 1,757 invasive colorectal cancers were identified from baseline to the end of follow-up, and from the date of administration of the meat-cooking module to the end of follow-up, respectively. Proportional hazards models were used to estimate basic and multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CIs) for colorectal cancer associated with dietary exposures. In multivariable models, no association with the risk of colorectal cancer was detected for density-adjusted total meat (RRQ5 vs Q1=0.93 [0.83–1.05]), red meat (RR =1.02 [0.91–1.16]), or processed meat intake (RR =1.06 [0.94–1.19]), or for total (RR =0.90 [0.76–1.05]) or specific HCA intake whether comparing quintiles of dietary exposure or using continuous variables. Although our results do not support a role for meat or for HCAs from meat in the etiology of colorectal cancer, we cannot rule out the possibility of a modest effect. PMID:22438055

Systematic review of the association between climate and hip fractures

NASA Astrophysics Data System (ADS)

Román Ortiz, Carmen; Tenías, José María; Estarlich, Marisa; Ballester, Ferran

2015-10-01

This study aims to systematically review epidemiological studies that evaluate the relationship between meteorology and the incidence of hip fracture (HF). After a search in Scopus, PubMed, and Embase, two independent authors assessed the relevance of studies and extracted data for description. From each study, we extracted the geographic and temporal scope, design, study variables (meteorological and related to HF), statistical analysis, and estimated associations. Of a total of 134 works, 20 studies were selected. All use an ecological design but one case-crossover. Most studies have been conducted in northern latitudes. The analysis methodology did not take into account the temporal structure of the data in 10 studies (regression and linear correlations); the rest used Poisson regression (7) and ARIMA model (3). Most studies showed significant positive associations with rainfall, especially in the form of snow: HF relative risk (RR) on days with precipitation vs. days without precipitation that ranged from 1.14 (95 % confidence interval (CI)1.04 to 1.24) to 1.60 (95 % CI 1.06 to 2.41), the temperature, with RR by one degree Celsius decline from 1.012 (95 % CI 1.004 to 1.020) to 1.030 (95 % CI 1.023 to 1.037), and wind (3) RR FC windiest days vs. calm days: 1.32 (95 % CI 1.10 to 1.58) to 1.35 (95 % CI 0.88 to 2.08). This review shows that analytic methods are very heterogeneous and poorly adapted to the temporary nature of the data. Studies confirm a certain seasonality, with more fractures in winter and meaningful relationships with meteorological conditions typical of this season.

Primary closure versus T-tube drainage in laparoscopic common bile duct exploration: a meta-analysis of randomized clinical trials.

PubMed

Wu, Xiangsong; Yang, Yong; Dong, Ping; Gu, Jun; Lu, Jianhua; Li, Maolan; Mu, Jiasheng; Wu, Wenguang; Yang, Jiahua; Zhang, Lin; Ding, Qichen; Liu, Yingbin

2012-08-01

To compare the safety and effectiveness of primary closure with those of T-tube drainage in laparoscopic common bile duct exploration (LCBDE) for choledocholithiasis. A comprehensive search was performed in the PubMed, EmBase, and Cochrane Library databases. Only randomized controlled trials comparing primary closure with T-tube drainage in LCBDE were considered eligible for this meta-analysis. The analyzed outcome variables included postoperative mortality, overall morbidity, biliary complication rate, biliary leak rate, reoperation, operating time, postoperative hospital stay, time to abdominal drain removal, and retained stone. All calculations and statistical tests were performed using ReviewerManager 5.1.2 software. A total of 295 patients (148 patients with primary closure and 147 patients with T-tube drainage) from three trials were identified and analyzed. No deaths occurred in any of the trials. Primary closure showed significantly better results in terms of morbidity (risk ratio (RR), 0.51; 95% confidence interval (CI), 0.30 to 0.88), biliary complication without a combination of retained stone (RR, 0.44; 95% CI, 0.20 to 0.97), reoperation (RR, 0.16; 95% CI, 0.03 to 0.87), operating time (mean difference (MD), -20.72; 95% CI, -29.59 to -11.85), postoperative hospital stay (MD, -3.24; 95% CI, -3.96 to -2.52), and time to abdominal drainage removal (MD, -0.45; 95% CI, -0.86 to -0.04). Statistically significant differences were not found between the two methods in terms of biliary leak, biliary complication, and retained stones. The current meta-analysis indicates that primary closure of the common bile duct is safer and more effective than T-tube drainage for LCBDE. Therefore, we do not recommend routine performance of T-tube drainage in LCBDE.

Cumulative probability of neodymium: YAG laser posterior capsulotomy after phacoemulsification.

PubMed

Ando, Hiroshi; Ando, Nobuyo; Oshika, Tetsuro

2003-11-01

To retrospectively analyze the cumulative probability of neodymium:YAG (Nd:YAG) laser posterior capsulotomy after phacoemulsification and to evaluate the risk factors. Ando Eye Clinic, Kanagawa, Japan. In 3997 eyes that had phacoemulsification with an intact continuous curvilinear capsulorhexis, the cumulative probability of posterior capsulotomy was computed by Kaplan-Meier survival analysis and risk factors were analyzed using the Cox proportional hazards regression model. The variables tested were sex; age; type of cataract; preoperative best corrected visual acuity (BCVA); presence of diabetes mellitus, diabetic retinopathy, or retinitis pigmentosa; type of intraocular lens (IOL); and the year the operation was performed. The IOLs were categorized as 3-piece poly(methyl methacrylate) (PMMA), 1-piece PMMA, 3-piece silicone, and acrylic foldable. The cumulative probability of capsulotomy after cataract surgery was 1.95%, 18.50%, and 32.70% at 1, 3, and 5 years, respectively. Positive risk factors included a better preoperative BCVA (P =.0005; risk ratio [RR], 1.7; 95% confidence interval [CI], 1.3-2.5) and the presence of retinitis pigmentosa (P<.0001; RR, 6.6; 95% CI, 3.7-11.6). Women had a significantly greater probability of Nd:YAG laser posterior capsulotomy (P =.016; RR, 1.4; 95% CI, 1.1-1.8). The type of IOL was significantly related to the probability of Nd:YAG laser capsulotomy, with the foldable acrylic IOL having a significantly lower probability of capsulotomy. The 1-piece PMMA IOL had a significantly higher risk than 3-piece PMMA and 3-piece silicone IOLs. The probability of Nd:YAG laser capsulotomy was higher in women, in eyes with a better preoperative BCVA, and in patients with retinitis pigmentosa. The foldable acrylic IOL had a significantly lower probability of capsulotomy.

Alcohol Use Disorders and Perceived Drinking Norms: Ethnic Differences in Israeli Adults

PubMed Central

Shmulewitz, Dvora; Wall, Melanie M.; Keyes, Katherine M.; Aharonovich, Efrat; Aivadyan, Christina; Greenstein, Eliana; Spivak, Baruch; Weizman, Abraham; Frisch, Amos; Hasin, Deborah

2012-01-01

Objective: Individuals’ perceptions of drinking acceptability in their society (perceived injunctive drinking norms) are widely assumed to explain ethnic group differences in drinking and alcohol use disorders (AUDs), but this has never been formally tested. Immigrants to Israel from the former Soviet Union (FSU) are more likely to drink and report AUD symptoms than other Israelis. We tested perceived drinking norms as a mediator of differences between FSU immigrants and other Israelis in drinking and AUDs. Method: Adult household residents (N = 1,349) selected from the Israeli population register were assessed with a structured interview measuring drinking, AUD symptoms, and perceived drinking norms. Regression analyses were used to produce odds ratios (OR) and risk ratios (RR) and 95% confidence intervals (CI) to test differences between FSU immigrants and other Israelis on binary and graded outcomes. Mediation of FSU effects by perceived drinking norms was tested with bootstrapping procedures. Results: FSU immigrants were more likely than other Israelis to be current drinkers (OR = 2.39, CI [1.61, 3.55]), have higher maximum number of drinks per day (RR = 1.88, CI [1.64, 2.16]), have any AUD (OR = 1.75, CI [1.16, 2.64]), score higher on a continuous measure of AUD (RR = 1.44, CI [1.12, 1.84]), and perceive more permissive drinking norms (p < .0001). For all four drinking variables, the FSU group effect was at least partially mediated by perceived drinking norms. Conclusions: This is the first demonstration that drinking norms mediate ethnic differences in AUDs. This work contributes to understanding ethnic group differences in drinking and AUDs, potentially informing etiologic research and public policy aimed at reducing alcohol-related harm. PMID:23036217

Persistence of transmitted HIV-1 drug resistance mutations associated with fitness costs and viral genetic backgrounds.

PubMed

Yang, Wan-Lin; Kouyos, Roger D; Böni, Jürg; Yerly, Sabine; Klimkait, Thomas; Aubert, Vincent; Scherrer, Alexandra U; Shilaih, Mohaned; Hinkley, Trevor; Petropoulos, Christos; Bonhoeffer, Sebastian; Günthard, Huldrych F

2015-03-01

Transmission of drug-resistant pathogens presents an almost-universal challenge for fighting infectious diseases. Transmitted drug resistance mutations (TDRM) can persist in the absence of drugs for considerable time. It is generally believed that differential TDRM-persistence is caused, at least partially, by variations in TDRM-fitness-costs. However, in vivo epidemiological evidence for the impact of fitness costs on TDRM-persistence is rare. Here, we studied the persistence of TDRM in HIV-1 using longitudinally-sampled nucleotide sequences from the Swiss-HIV-Cohort-Study (SHCS). All treatment-naïve individuals with TDRM at baseline were included. Persistence of TDRM was quantified via reversion rates (RR) determined with interval-censored survival models. Fitness costs of TDRM were estimated in the genetic background in which they occurred using a previously published and validated machine-learning algorithm (based on in vitro replicative capacities) and were included in the survival models as explanatory variables. In 857 sequential samples from 168 treatment-naïve patients, 17 TDRM were analyzed. RR varied substantially and ranged from 174.0/100-person-years;CI=[51.4, 588.8] (for 184V) to 2.7/100-person-years;[0.7, 10.9] (for 215D). RR increased significantly with fitness cost (increase by 1.6[1.3,2.0] per standard deviation of fitness costs). When subdividing fitness costs into the average fitness cost of a given mutation and the deviation from the average fitness cost of a mutation in a given genetic background, we found that both components were significantly associated with reversion-rates. Our results show that the substantial variations of TDRM persistence in the absence of drugs are associated with fitness-cost differences both among mutations and among different genetic backgrounds for the same mutation.

Fractal analysis of heart rate dynamics as a predictor of mortality in patients with depressed left ventricular function after acute myocardial infarction. TRACE Investigators. TRAndolapril Cardiac Evaluation

NASA Technical Reports Server (NTRS)

Makikallio, T. H.; Hoiber, S.; Kober, L.; Torp-Pedersen, C.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

1999-01-01

A number of new methods have been recently developed to quantify complex heart rate (HR) dynamics based on nonlinear and fractal analysis, but their value in risk stratification has not been evaluated. This study was designed to determine whether selected new dynamic analysis methods of HR variability predict mortality in patients with depressed left ventricular (LV) function after acute myocardial infarction (AMI). Traditional time- and frequency-domain HR variability indexes along with short-term fractal-like correlation properties of RR intervals (exponent alpha) and power-law scaling (exponent beta) were studied in 159 patients with depressed LV function (ejection fraction <35%) after an AMI. By the end of 4-year follow-up, 72 patients (45%) had died and 87 (55%) were still alive. Short-term scaling exponent alpha (1.07 +/- 0.26 vs 0.90 +/- 0.26, p <0.001) and power-law slope beta (-1.35 +/- 0.23 vs -1.44 +/- 0.25, p <0.05) differed between survivors and those who died, but none of the traditional HR variability measures differed between these groups. Among all analyzed variables, reduced scaling exponent alpha (<0.85) was the best univariable predictor of mortality (relative risk 3.17, 95% confidence interval 1.96 to 5.15, p <0.0001), with positive and negative predictive accuracies of 65% and 86%, respectively. In the multivariable Cox proportional hazards analysis, mortality was independently predicted by the reduced exponent alpha (p <0.001) after adjustment for several clinical variables and LV function. A short-term fractal-like scaling exponent was the most powerful HR variability index in predicting mortality in patients with depressed LV function. Reduction in fractal correlation properties implies more random short-term HR dynamics in patients with increased risk of death after AMI.

Locomotor Performance During Rehabilitation of People With Lower Limb Amputation and Prosthetic Nonuse 12 Months After Discharge.

PubMed

Roffman, Caroline E; Buchanan, John; Allison, Garry T

2016-07-01

It is recognized that multifactorial assessments are needed to evaluate balance and locomotor function in people with lower limb amputation. There is no consensus on whether a single screening tool could be used to identify future issues with locomotion or prosthetic use. The purpose of this study was to determine whether different tests of locomotor performance during rehabilitation were associated with significantly greater risk of prosthetic abandonment at 12 months postdischarge. This was a retrospective cohort study. Data for descriptive variables and locomotor tests (ie, 10-Meter Walk Test [10MWT], Timed "Up & Go" Test [TUGT], Six-Minute Walk Test [6MWT], and Four Square Step Test [FSST]) were abstracted from the medical records of 201 consecutive participants with lower limb amputation. Participants were interviewed and classified as prosthetic users or nonusers at 12 months postdischarge. The Mann-Whitney U test was used to analyze whether there were differences in locomotor performance. Receiver operating characteristic curves were generated to determine performance thresholds, and relative risk (RR) was calculated for nonuse. At 12 months postdischarge, 18% (n=36) of the participants had become prosthetic nonusers. Performance thresholds, area under the curve (AUC), and RR of nonuse (95% confidence intervals [CI]) were: for the 10MWT, if walking speed was ≤0.44 ms(-1) (AUC=0.743), RR of nonuse=2.76 (95% CI=1.83, 3.79; P<.0001); for the TUGT, if time was ≥21.4 seconds (AUC=0.796), RR of nonuse=3.17 (95% CI=2.17, 4.14; P<.0001); for the 6MWT, if distance was ≤191 m (AUC=0.788), RR of nonuse=2.84, (95% CI=2.05, 3.48; P<.0001); and for the FSST, if time was ≥36.6 seconds (AUC=0.762), RR of nonuse=2.76 (95% CI=1.99, 3.39; P<.0001). Missing data, potential recall bias, and assessment times that varied were limitations of the study. Locomotor performance during rehabilitation may predict future risk of prosthetic nonuse. It may be implied that the 10MWT has the greatest clinical utility as a single screening tool for prosthetic nonuse, given the highest proportion of participants were able to perform this test early in rehabilitation. However, as locomotor skills improve, other tests (in particular, the 6MWT) have specific clinical utility. To fully enable implementation of these locomotor criteria for prosthetic nonuse into clinical practice, validation is warranted. © 2016 American Physical Therapy Association.

Examining intendedness among pregnancies ending in spontaneous abortion.

PubMed

Flink-Bochacki, Rachel; Meyn, Leslie A; Chen, Beatrice A; Achilles, Sharon L; Chang, Judy C; Borrero, Sonya

2017-08-01

Spontaneous abortion (SAB) affects over 1 million US women each year, yet little is known about the intendedness of these pregnancies. We examined prevalence and correlates of unintended and unwanted pregnancies ending in SAB. We used nationally-representative cross-sectional data of US women aged 15-44 from the 2011-2013 National Survey of Family Growth to examine pregnancies ending in SAB. We used modified Poisson regression models to evaluate associations between demographic and pregnancy characteristics with unintended and unwanted pregnancy. Among 1351 pregnancies ending in SAB, 44.5% were unintended (i.e. unwanted or occurring sooner than desired). Younger women with SAB were more likely to report unintended pregnancies than women 30-44 years, and women 15-19 years reported unintended pregnancy most often [adjusted relative risk (aRR)=3.0; 95% confidence interval (CI): 2.2-4.1]. Unintended pregnancy was two times more likely among unmarried than married women [never married: aRR=2.2; 95% CI: 1.7-2.7; previously married: aRR=2.2; 95% CI: 1.7-3.0]. Other factors associated with unintended pregnancy were multiparity compared to nulliparity [aRR=2.6; 95% CI: 1.7-4.1 for ≥3 children; aRR=1.8; 95% CI: 1.3-2.5 for 2 children] and inter-pregnancy interval ≤12 months compared to >12 months [aRR=1.4; 95% CI: 1.2-1.7]. We found similar associations with unwanted pregnancies ending in SAB (15.3% of pregnancies). Neither race/ethnicity nor socioeconomic indicators were independently associated with unintended or unwanted pregnancy ending in SAB. Many pregnancies ending in spontaneous abortion are unintended and/or unwanted. Women with pregnancy loss, like all reproductive-aged women, should receive comprehensive counseling about reproductive planning and contraception. Similar to all pregnancies, nearly half of pregnancies ending in spontaneous abortion are unintended and/or unwanted, suggesting that many women experiencing spontaneous abortion may benefit from a review of family planning desires and the provision of reproductive planning counseling and effective contraception to prevent future undesired pregnancy. Copyright © 2017 Elsevier Inc. All rights reserved.

A machine learned classifier for RR Lyrae in the VVV survey

NASA Astrophysics Data System (ADS)

Elorrieta, Felipe; Eyheramendy, Susana; Jordán, Andrés; Dékány, István; Catelan, Márcio; Angeloni, Rodolfo; Alonso-García, Javier; Contreras-Ramos, Rodrigo; Gran, Felipe; Hajdu, Gergely; Espinoza, Néstor; Saito, Roberto K.; Minniti, Dante

2016-11-01

Variable stars of RR Lyrae type are a prime tool with which to obtain distances to old stellar populations in the Milky Way. One of the main aims of the Vista Variables in the Via Lactea (VVV) near-infrared survey is to use them to map the structure of the Galactic Bulge. Owing to the large number of expected sources, this requires an automated mechanism for selecting RR Lyrae, and particularly those of the more easily recognized type ab (I.e., fundamental-mode pulsators), from the 106-107 variables expected in the VVV survey area. In this work we describe a supervised machine-learned classifier constructed for assigning a score to a Ks-band VVV light curve that indicates its likelihood of being ab-type RR Lyrae. We describe the key steps in the construction of the classifier, which were the choice of features, training set, selection of aperture, and family of classifiers. We find that the AdaBoost family of classifiers give consistently the best performance for our problem, and obtain a classifier based on the AdaBoost algorithm that achieves a harmonic mean between false positives and false negatives of ≈7% for typical VVV light-curve sets. This performance is estimated using cross-validation and through the comparison to two independent datasets that were classified by human experts.

Meteorological factors affecting dengue incidence in Davao, Philippines.

PubMed

Iguchi, Jesavel A; Seposo, Xerxes T; Honda, Yasushi

2018-05-15

Dengue fever is a major public health concern in the Philippines, and has been a significant cause of hospitalizations and deaths among young children. Previous literature links climate change to dengue, and with increasingly unpredictable changing climate patterns, there is a need to understand how these meteorological variables affect dengue incidence in a highly endemic area. Weekly dengue incidences (2011-2015) in Davao Region, Philippines were obtained from the Department of Health. Same period of weekly local meteorological variables were obtained from the National Climatic Data Center (NCDC) and the National Oceanic and Atmospheric Administration (NOAA). Wavelet coherence analysis was used to determine the presence of non-stationary relationships, while a quasi-Poisson regression combined with distributed lag nonlinear model (DLNM) was used to analyze the association between meteorological variables and dengue incidences. Significant periodicity was detected in the 7 to 14-week band between the year 2011-2012 and a 26-week periodicity from the year 2013-2014. Overall cumulative risks were particularly high for rainfall at 32 mm (RR: 1.67, 95% CI: 1.07-2.62), while risks were observed to increase with increasing dew point. On the other hand, lower average temperature of 26 °C has resulted to an increased RR of dengue (RR: 1.96, 95% CI: 0.47-8.15) while higher temperature from 27 °C to 31 °C has lower RR. The observed possible threshold levels of these meteorological variables can be integrated into an early warning system to enhance dengue prediction for better vector control and management in the future.

[The influence of occupational lead exposure on transmural repolarization dispersion].

PubMed

Zyśko, Dorota; Gajek, Jacek; Chlebda, Ewa; Mazurek, Walentyna

2005-02-01

The parts of QT interval: time from Q wave to the peak of T wave (QTp) representing the de- and repolarization of subepicardial layer and the time from the peak of T wave to its end (QTp-e) building the transmural dispersion of repolarization enable more exact assessment of repolarization period of the heart muscle. Occupational exposure to lead influences the electrophysiologic properties of the heart. The aim of our study was to assess the QTp and QTp-e interval in workers occupationally exposed to lead. The study was carried out in 22 copper smelters aged 41.8 +/- 8.7 years, occupationally exposed to lead. The control group consisted of 14 healthy men. In all studied subjects blood lead concentration (Pb) and the concentration of free protoporphyrins in erytrocytes were assessed. 24-hour ECG holter monitoring was done to study rhythm disturbances and the duration in lead CM5 of QT interval, QTp interval, RR interval preceding the assessed QT interval (pRR) during sleep, rest during the awake state and moderate daily activity. The QTp-e interval is the difference between the duration of QT and QTp interval. The duration of QTp and QTp-e in occupationally exposed workers and healthy persons did not differ significantly. These parameters were significantly lower in both groups during moderately physical activity comparing to the values during sleep. The QTp-e/ QTp ratio in occupationally exposed workers during night hours was significantly lower than during daily activity what was not the case in control persons. Occupational exposure to lead do not change significantly the transmural dispersion of repolarization. Occupational exposure to lead diminishes the QTp-e/QTp ratio during the night.

A new approach to correct the QT interval for changes in heart rate using a nonparametric regression model in beagle dogs.

PubMed

Watanabe, Hiroyuki; Miyazaki, Hiroyasu

2006-01-01

Over- and/or under-correction of QT intervals for changes in heart rate may lead to misleading conclusions and/or masking the potential of a drug to prolong the QT interval. This study examines a nonparametric regression model (Loess Smoother) to adjust the QT interval for differences in heart rate, with an improved fitness over a wide range of heart rates. 240 sets of (QT, RR) observations collected from each of 8 conscious and non-treated beagle dogs were used as the materials for investigation. The fitness of the nonparametric regression model to the QT-RR relationship was compared with four models (individual linear regression, common linear regression, and Bazett's and Fridericia's correlation models) with reference to Akaike's Information Criterion (AIC). Residuals were visually assessed. The bias-corrected AIC of the nonparametric regression model was the best of the models examined in this study. Although the parametric models did not fit, the nonparametric regression model improved the fitting at both fast and slow heart rates. The nonparametric regression model is the more flexible method compared with the parametric method. The mathematical fit for linear regression models was unsatisfactory at both fast and slow heart rates, while the nonparametric regression model showed significant improvement at all heart rates in beagle dogs.

Catheter-Related Complications in Children With Cancer Receiving Parenteral Nutrition: Change in Risk Is Moderated by Catheter Type.

PubMed

Shenep, Melissa A; Tanner, Mary R; Sun, Yilun; Culley, Tina; Hayden, Randall T; Flynn, Patricia M; Tang, Li; Wolf, Joshua

2017-08-01

Although central venous catheters (CVCs) are essential to pediatric cancer care, complications are common (eg, occlusion, central line-associated bloodstream infection [CLABSI]). Parenteral nutrition (PN) and external CVCs are associated with an increased complication risk, but their interaction is unknown. A retrospective matched cohort study of pediatric oncology patients who received PN through subcutaneous ports or external CVCs. Complication rates were compared between CVC types during PN and non-PN periods (log-negative binomial model). Risk of CLABSI was higher during PN for children with ports (relative risk [RR] = 39.6; 95% confidence interval, 5.0-309) or external CVCs (RR = 2.9; 95% confidence interval, 1.1-7.4). This increased risk during PN was greater for ports than for external CVCs (ratio of relative risks = 13.6). Occlusion risk was higher during PN in both groups (RR = 10.0 for ports; RR = 2.0 for external CVCs), and the increase was significantly greater in ports (ratio of relative risks, 4.9). Overall, complication rates for ports were much lower than for external CVCs during the non-PN period but similar during the PN period. Children with cancer who receive PN have increased risk of CLABSI and occlusion. The risk increase is greatest in children with ports: a 40- and 10-fold increase in infection risk and occlusion, respectively, resulting in similar complication rates during PN regardless of CVC type and negating the usual benefits of ports. Children with cancer who will require PN should have primary insertion of external CVCs where possible.

Microgravity alters respiratory sinus arrhythmia and short-term heart rate variability in humans

NASA Technical Reports Server (NTRS)

Migeotte, P-F; Prisk, G. Kim; Paiva, M.; West, J. B. (Principal Investigator)

2003-01-01

We studied heart rate (HR), heart rate variability (HRV), and respiratory sinus arrhythmia (RSA) in four male subjects before, during, and after 16 days of spaceflight. The electrocardiogram and respiration were recorded during two periods of 4 min controlled breathing at 7.5 and 15 breaths/min in standing and supine postures on the ground and in microgravity. Low (LF)- and high (HF)-frequency components of the short-term HRV (< or =3 min) were computed through Fourier spectral analysis of the R-R intervals. Early in microgravity, HR was decreased compared with both standing and supine positions and had returned to the supine value by the end of the flight. In microgravity, overall variability, the LF-to-HF ratio, and RSA amplitude and phase were similar to preflight supine values. Immediately postflight, HR increased by approximately 15% and remained elevated 15 days after landing. LF/HF was increased, suggesting an increased sympathetic control of HR standing. The overall variability and RSA amplitude in supine decreased postflight, suggesting that vagal tone decreased, which coupled with the decrease in RSA phase shift suggests that this was the result of an adaptation of autonomic control of HR to microgravity. In addition, these alterations persisted for at least 15 days after return to normal gravity (1G).

Modeling heart rate variability including the effect of sleep stages

NASA Astrophysics Data System (ADS)

Soliński, Mateusz; Gierałtowski, Jan; Żebrowski, Jan

2016-02-01

We propose a model for heart rate variability (HRV) of a healthy individual during sleep with the assumption that the heart rate variability is predominantly a random process. Autonomic nervous system activity has different properties during different sleep stages, and this affects many physiological systems including the cardiovascular system. Different properties of HRV can be observed during each particular sleep stage. We believe that taking into account the sleep architecture is crucial for modeling the human nighttime HRV. The stochastic model of HRV introduced by Kantelhardt et al. was used as the initial starting point. We studied the statistical properties of sleep in healthy adults, analyzing 30 polysomnographic recordings, which provided realistic information about sleep architecture. Next, we generated synthetic hypnograms and included them in the modeling of nighttime RR interval series. The results of standard HRV linear analysis and of nonlinear analysis (Shannon entropy, Poincaré plots, and multiscale multifractal analysis) show that—in comparison with real data—the HRV signals obtained from our model have very similar properties, in particular including the multifractal characteristics at different time scales. The model described in this paper is discussed in the context of normal sleep. However, its construction is such that it should allow to model heart rate variability in sleep disorders. This possibility is briefly discussed.

Safety of Tenofovir Disoproxil Fumarate–Based Antiretroviral Therapy Regimens in Pregnancy for HIV-Infected Women and Their Infants: A Systematic Review and Meta-Analysis

PubMed Central

Uthman, Olalekan A.; Mofenson, Lynne M.; Anderson, Jean R.; Kanters, Steve; Renaud, Francoise; Ford, Nathan; Essajee, Shaffiq; Doherty, Meg C.; Mills, Edward J.

2017-01-01

Background: There are limited data on adverse effects of tenofovir disoproxil fumarate (TDF)-based antiretroviral therapy (ART) on pregnant women and their infants. Methods: We conducted a systematic review of studies published between January 1980 and January 2017 that compared adverse outcomes in HIV-infected women receiving TDF- vs. non–TDF-based ART during pregnancy. The risk ratio (RR) for associations was pooled using a fixed-effects model. Results: Seventeen studies met the study inclusion criteria. We found that the rate of preterm (<37 weeks gestation) delivery (RR = 0.90, 95% confidence interval [CI]: 0.81 to 0.99, I2 = 59%) and stillbirth (RR = 0.60, 95% CI: 0.43 to 0.84, I2 = 72.0%) were significantly lower in women exposed (vs. not) to TDF-based ART regimen. We found no increased risk in maternal severe (grade 3) or potentially life-threatening (grade 4) adverse events (RR = 0.62; 95% CI: 0.30 to 1.29), miscarriage (RR = 1.09; 95% CI: 0.80 to 1.48), very preterm (<34 weeks gestation) delivery (RR = 1.08, 95% CI: 0.72 to 1.62), small for gestational age (RR = 0.87, 95% CI: 0.67 to 1.13), low birth weight (RR = 0.91; 95% CI: 0.80 to 1.04), very low birth weight (RR = 3.18; 95% CI: 0.65 to 15.63), congenital anomalies (RR = 1.03; 95% CI: 0.83 to 1.28), infant adverse outcomes or infant mortality (age >14 days) (RR = 0.65; 95% CI: 0.23 to 1.85), but increased neonatal mortality (age <14 days) risk (RR = 5.64, 95% CI: 1.70 to 18.79) with TDR-based ART exposure. No differences were found for anthropomorphic parameters at birth; one study reported minor differences in z-scores for length and head circumference at age 1 year. Conclusions: TDF-based ART in pregnancy seems generally safe for women and their infants. However, data remain limited and further studies are needed, particularly to assess neonatal mortality and infant growth/bone effects. PMID:28291053

Risk of immune-related colitis with PD-1/PD-L1 inhibitors vs chemotherapy in solid tumors: systems assessment.

PubMed

Su, Qiang; Zhang, Xiaochen; Shen, Xinhua; Hou, Yanli; Sun, Zhigang; Gao, Zu Hua

2018-01-01

Background: We performed a meta-analysis to evaluate the risk of immune-related colitis associated with PD1/PD-L1 inhibitors as compared to chemotherapy in solid tumor patients. Methods: Eligible studies were identified through a comprehensive search of multiple databases and included solid tumor patients in randomized controlled trials (RCTs) with PD-1/PD-L1 inhibitors. The data was analyzed by Stata version 12.0 software. Results: After exclusion of ineligible studies, 11 clinical trials were considered eligible for the meta-analysis, including 5751 patients. Compared with chemotherapy, the risk ratios (RRs) of all-grade colitis were significant for the PD-1 inhibitor subgroup (RR 2.69, 95% confidence interval (CI): 1.15-6.29, p=0.023), and for pembrolizumab subgroup (RR 3.17, 95% CI: 1.08-9.37, p=0.037), but not for nivolumab treatment and PD-L1 inhibitor (atezolizumab) treatment (RR 2.05, 95% CI: 0.52-8.13, p=0.305; RR 4.75,95% CI: 0.56-40.50, p=0.154, respectively). The RR of all-grade colitis was significant for PD-1/PD-L1 inhibitor in NSCLC (RR 4.34, 95% CI: 1.37-13.82, p=0.013), and not significant in melanoma (RR 2.11, 95% CI: 0.54-8.34, p=0.285). Moreover, the RRs of all-grade diarrhea were significant for the PD-1 inhibitor subgroup (RR 0.61, 95% CI: 0.44-0.83, p=0.002), for the nivolumab subgroup (RR 0.54, 95% CI: 0.34-0.87, p=0.012), and for atezolizumab subgroup (RR 0.48, 95% CI: 0.25-0.89, p=0.021). The RR of high-grade diarrhea was significant for atezolizumab subgroup (RR 0.34, 95% CI: 0.12-0.94, p=0.037). Conclusions: Our meta-analysis demonstrates that compared with chemotherapy, pembrolizumab may result in a higher risk of all-grade immune-mediated colitis. PD-1/PD-L1 inhibitor treatment in NSCLC patients, but not in melanoma patients, increases the risk of all-grade colitis incidence.

Effects of noradrenaline on human vagal baroreflexes

NASA Technical Reports Server (NTRS)

Airaksinen, K. E.; Huikuri, H. V.; Huhti, L.; Kuusela, T. A.; Tahvanainen, K. U.; Tulppo, M.; Makikallio, T.; Eckberg, D. L.

2001-01-01

BACKGROUND: Baroreflex sensitivity (BRS) is depressed in conditions associated with high sympathetic nerve activity in proportion to circulating noradrenaline (NA) levels. Despite the prognostic importance of measurements of BRS in patients, there is little information on how high NA levels affect arterial baroreflex function. AIM: To understand better the role of NA in cardiovascular homeostasis. METHODS: We gave incremental intravenous NA infusions (at 50 and 100 ng/kg/min) to 12 healthy young men. We measured RR intervals and photoplethysmographic arterial pressures and estimated BRS with cross-spectral and sequence methods during metronome-guided respiration at 0.25 Hz. RESULTS: The high NA infusion rate significantly increased respiratory-frequency (0.15-0.40 Hz) RR interval spectral power and decreased low-frequency (0.04-0.15 Hz) systolic pressure spectral power compared with baseline levels (P < 0.05 for both). Cross-spectral BRS increased from an average (+/- SD) baseline level of 17.3+/-6.6 to 34.1+/-20.8 ms/mmHg at the high NA infusion rate (P < 0.05). Sequence BRS values did not increase significantly during NA infusions. The percentage of sequences with parallel changes in systolic pressures and RR intervals decreased progressively from a baseline level of 16.0+/-12.9 to 10.1+/-7.4 during the low NA infusion rate and to 6.2+/-6.2% during the high rate (P < 0.05 and 0.01, respectively). CONCLUSIONS: Increases in circulating NA to high physiological levels do not depress BRS but interfere with the close baroreflex-mediated coupling that is usually present between arterial pressure and heart rate.

Automated measurements for individualized heart rate correction of the QT interval.

PubMed

Mason, Jay W; Moon, Thomas E

2015-04-01

Subject-specific electrocardiographic QT interval correction for heart rate is often used in clinical trials with frequent electrocardiographic recordings. However, in these studies relatively few 10-s, 12-lead electrocardiograms may be available for calculating the individual correction. Highly automated QT and RR measurement tools have made it practical to measure electrocardiographic intervals on large volumes of continuous electrocardiogram data. The purpose of this study was to determine whether an automated method can be used in lieu of a manual method. In 49 subjects who completed all treatments in a four-armed crossover study we compared two methods for derivation of individualized rate-correction coefficients: manual measurement on 10-s electrocardiograms and automated measurement of QT and RR during continuous 24-h electrocardiogram recordings. The four treatments, received by each subject in a latin-square randomization sequence were placebo, moxifloxacin, and two doses of an investigational drug. Analysis of continuous electrocardiogram data yielded a lower standard deviation of QT:RR regression values than the manual method, though the differences were not statistically significant. The within-subject and within-treatment coefficients of variation between the manual and automated methods were not significantly different. Corrected QT values from the two methods had similar rates of true and false positive identification of moxifloxacin's QT prolonging effect. An automated method for individualized rate correction applied to continuous electrocardiogram data could be advantageous in clinical trials, as the automated method is simpler, is based upon a much larger volume of data, yields similar results, and requires no human over-reading of the measurements. © The Author(s) 2015.

Reduced Baroreflex Sensitivity in Cluster Headache Patients.

PubMed

Barloese, Mads C J; Mehlsen, Jesper; Brinth, Louise; Lundberg, Helena I S; Jennum, Poul J; Jensen, Rigmor H

2015-06-01

Important elements of cluster headache (CH) pathophysiology may be seated in the posterior hypothalamus. Cranial autonomic features are inherent, but involvement of systemic autonomic control is still debated. We aimed to characterize autonomic function as investigated by baroreflex sensitivity (BRS) in CH patients. Twenty-six active CH patients and an equal number of age-, sex-, and BMI-matched controls underwent head-up tilt table test and BRS was determined by the sequence method. Compared with controls, patients exhibited a blunted reactivity of RR intervals in response to falls and increases in systolic blood pressure (SBP) (15.3 vs. 20.0 ms/mmHg, P = .0041) in the supine position. Also, compared with controls, BRS was lower in patients having suffered an attack within the past 12 hours (n = 13, 12.5 vs. 22.3 ms/mmHg, P = .0091), opposed to those patients who had not (n = 13, 16.0 ms/mmHg, P = .1523). In the tilted position, the drop in SBP at the carotid sinuses was higher in patients who had recently suffered an attack. Despite this, they exhibited a less marked shortening of RR intervals when compared with patients who had been attack free for longer. CH patients exhibit a subclinical blunting of BRS that may be affected by the attacks themselves. The fast RR interval fluctuations used in this method reflects cardiovagal responses, thus the blunted responses are suggestive of dysfunction in the parasympathetic division of the autonomic nervous system or in the central relay of impulses from the baroreceptors. © 2015 American Headache Society.

Antioxidant intake from fruits, vegetables and other sources and risk of non-Hodgkin's lymphoma: the Iowa Women's Health Study.

PubMed

Thompson, Carrie A; Habermann, Thomas M; Wang, Alice H; Vierkant, Robert A; Folsom, Aaron R; Ross, Julie A; Cerhan, James R

2010-02-15

Antioxidant nutrients found in fruits, vegetables and other foods are thought to inhibit carcinogenesis and to influence immune status. We evaluated the association of these factors with risk of non-Hodgkin's lymphoma (NHL) overall and for diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma specifically in a prospective cohort of 35,159 Iowa women aged 55-69 years when enrolled at baseline in 1986. Diet was ascertained using a validated semiquantitative food frequency questionnaire. Through 2005, 415 cases of NHL (including 184 DLBCL and 90 follicular) were identified. Relative risks (RRs) and 95% confidence intervals (CIs) were estimated using Cox regression, adjusting for age and total energy. The strongest associations of antioxidants with risk of NHL (RR for highest versus lowest quartile; p for trend) were observed for dietary vitamin C (RR = 0.78; p = 0.044), alpha-carotene (RR = 0.71; p = 0.015), proanthocyanidins (RR = 0.70; p = 0.0024) and dietary manganese (RR = 0.62; p = 0.010). There were no associations with multivitamin use or supplemental intake of vitamins C, E, selenium, zinc, copper or manganese. From a food perspective, greater intake of total fruits and vegetables (RR = 0.69; p = 0.011), yellow/orange (RR = 0.72; p = 0.015) and cruciferous (RR = 0.82; p = 0.017) vegetables, broccoli (RR = 0.72; p = 0.018) and apple juice/cider (RR = 0.65; p = 0.026) were associated with lower NHL risk; there were no strong associations for other antioxidant-rich foods, including whole grains, chocolate, tea or nuts. Overall, these associations were mainly observed for follicular lymphoma and were weaker or not apparent for DLBCL. In conclusion, these results support a role for vegetables, and perhaps fruits and associated antioxidants from food sources, as protective factors against the development of NHL and follicular lymphoma in particular.

Telephone triage by GPs in out-of-hours primary care in Denmark: a prospective observational study of efficiency and relevance

PubMed Central

Huibers, Linda; Moth, Grete; Carlsen, Anders H; Christensen, Morten B; Vedsted, Peter

2016-01-01

Background In the UK, telephone triage in out-of-hours primary care is mostly managed by nurses, whereas GPs perform triage in Denmark. Aim To describe telephone contacts triaged to face-to-face contacts, GP-assessed relevance, and factors associated with triage to face-to-face contact. Design and setting A prospective observational study in Danish out-of-hours primary care, conducted from June 2010 to May 2011. Method Information on patients was collected from the electronic patient administration system and GPs completed electronic questionnaires about the contacts. The GPs conducting the face-to-face contacts assessed relevance of the triage to face-to-face contacts. The authors performed binomial regression analyses, calculating relative risk (RR) and 95% confidence intervals. Results In total, 59.2% of calls ended with a telephone consultation. Factors associated with triage to a face-to-face contact were: patient age >40 years (40–64: RR = 1.13; >64: RR = 1.34), persisting problem for 12–24 hours (RR = 1.15), severe problem (RR = 2.60), potentially severe problem (RR = 5.81), and non-severe problem (RR = 2.23). Face-to-face contacts were assessed as irrelevant for 12.7% of clinic consultations and 11.7% of home visits. A statistically significantly higher risk of irrelevant face-to-face contact was found for a persisting problem of >24 hours (RR = 1.25), contact on weekday nights (RR = 1.25), and contact <2 hours before the patient’s own GP’s opening time (RR = 1.80). Conclusion Around 12% of all face-to-face consultations in the study are assessed as irrelevant by GP colleagues, suggesting that GP triage is efficient. Knowledge of the factors influencing triage can provide better education for GPs, but future studies are needed to investigate other quality aspects of GP telephone triage. PMID:27432608

Antioxidant Intake from Fruits, Vegetables and Other Sources and Risk of Non-Hodgkin Lymphoma: The Iowa Women's Health Study

PubMed Central

Thompson, Carrie A.; Habermann, Thomas M.; Wang, Alice H.; Vierkant, Robert A.; Folsom, Aaron R.; Ross, Julie A.; Cerhan, James R.

2009-01-01

Antioxidant nutrients found in fruits, vegetables, and other foods are thought to inhibit carcinogenesis and to influence immune status. We evaluated the association of these factors with risk of NHL overall and for diffuse large B-cell (DLBCL) and follicular lymphoma specifically in a prospective cohort of 35,159 Iowa women aged 55–69 years when enrolled at baseline in 1986. Diet was ascertained using a validated semi-quantitative food frequency questionnaire. Through 2005, 415 cases of NHL (including 184 DLBCL and 90 follicular) were identified. Relative risks (RRs) and 95% confidence intervals (CI) were estimated using Cox regression, adjusting for age and total energy. The strongest associations of antioxidants with risk of NHL (RR for highest versus lowest quartile; p for trend) were observed for dietary vitamin C (RR=0.78; p=0.044), α-carotene (RR=0.71; p=0.015), proanthocyanidins (RR=0.70; p=0.0024), and dietary manganese (RR=0.62; p=0.010). There were no associations with multivitamin use or supplemental intake of vitamins C, E, selenium, zinc, copper or manganese. From a food perspective, greater intake of total fruits and vegetables (RR=0.69; p=0.011), yellow/orange (RR=0.72; p=0.015) and cruciferous (RR=0.82; p=0.017) vegetables, broccoli (RR=0.72; p=0.018), and apple juice/cider (RR=0.65; p=0.026) were associated with lower NHL risk; there were no strong associations for other antioxidant-rich foods, including whole grains, chocolate, tea or nuts. Overall, these associations were mainly observed for follicular lymphoma, and were weaker or not apparent for DLBCL. In conclusion, these results support a role for vegetables and perhaps fruits, and associated antioxidants from food sources, as protective factors against the development of NHL and follicular lymphoma in particular. PMID:19685491

Complications after cardiac implantable electronic device implantations: an analysis of a complete, nationwide cohort in Denmark

PubMed Central

Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard; Jørgensen, Ole Dan; Nielsen, Jens Cosedis

2014-01-01

Aims Complications after cardiac implantable electronic device (CIED) treatment, including permanent pacemakers (PMs), cardiac resynchronization therapy devices with defibrillators (CRT-Ds) or without (CRT-Ps), and implantable cardioverter defibrillators (ICDs), are associated with increased patient morbidity, healthcare costs, and possibly increased mortality. Methods and results Population-based cohort study in all Danish patients who underwent a CIED procedure from May 2010 to April 2011. Data on complications were gathered on review of all patient charts while baseline data were obtained from the Danish Pacemaker and ICD Register. Adjusted risk ratios (aRRs) with 95% confidence intervals were estimated using binary regression. The study population consisted of 5918 consecutive patients. A total of 562 patients (9.5%) experienced at least one complication. The risk of any complication was higher if the patient was a female (aRR 1.3; 1.1–1.6), underweight (aRR 1.5; 1.1–2.3), implanted in a centre with an annual volume <750 procedures (0–249 procedures: aRR 1.6; 1.1–2.2, 250–499: aRR 2.0; 1.6–2.7, 500–749: aRR 1.5; 1.2–1.8), received a dual-chamber ICD (aRR 2.0; 1.4–2.7) or CRT-D (aRR 2.6; 1.9–3.4), underwent system upgrade or lead revision (aRR 1.3; 1.0–1.7), had an operator with an annual volume <50 procedures (aRR 1.9; 1.4–2.6), or underwent an emergency, out-of-hours procedure (aRR 1.5; 1.0–2.3). Conclusion CIED complications are more frequent than generally acknowledged. Both patient- and procedure-related predictors may identify patients with a particularly high risk of complications. This information should be taken into account both in individual patient treatment and in the planning of future organization of CIED treatment. PMID:24347317

A retrospective cohort study of cause-specific mortality and incidence of hematopoietic malignancies in Chinese benzene-exposed workers.

PubMed

Linet, Martha S; Yin, Song-Nian; Gilbert, Ethel S; Dores, Graça M; Hayes, Richard B; Vermeulen, Roel; Tian, Hao-Yuan; Lan, Qing; Portengen, Lutzen; Ji, Bu-Tian; Li, Gui-Lan; Rothman, Nathaniel

2015-11-01

Benzene exposure has been causally linked with acute myeloid leukemia (AML), but inconsistently associated with other hematopoietic, lymphoproliferative and related disorders (HLD) or solid tumors in humans. Many neoplasms have been described in experimental animals exposed to benzene. We used Poisson regression to estimate adjusted relative risks (RR) and the likelihood ratio statistic to derive confidence intervals for cause-specific mortality and HLD incidence in 73,789 benzene-exposed compared with 34,504 unexposed workers in a retrospective cohort study in 12 cities in China. Follow-up and outcome assessment was based on factory, medical and other records. Benzene-exposed workers experienced increased risks for all-cause mortality (RR = 1.1, 95% CI = 1.1, 1.2) due to excesses of all neoplasms (RR = 1.3, 95% CI = 1.2, 1.4), respiratory diseases (RR = 1.7, 95% CI = 1.2, 2.3) and diseases of blood forming organs (RR = ∞, 95% CI = 3.4, ∞). Lung cancer mortality was significantly elevated (RR = 1.5, 95% CI = 1.2, 1.9) with similar RRs for males and females, based on three-fold more cases than in our previous follow-up. Significantly elevated incidence of all myeloid disorders reflected excesses of myelodysplastic syndrome/acute myeloid leukemia (RR = 2.7, 95% CI = 1.2, 6.6) and chronic myeloid leukemia (RR = 2.5, 95% CI = 0.8, 11), and increases of all lymphoid disorders included excesses of non-Hodgkin lymphoma (RR = 3.9, 95%CI = 1.5, 13) and all lymphoid leukemia (RR = 5.4, 95%CI = 1.0, 99). The 28-year follow-up of Chinese benzene-exposed workers demonstrated increased risks of a broad range of myeloid and lymphoid neoplasms, lung cancer, and respiratory diseases and suggested possible associations with other malignant and non-malignant disorders. © 2015 UICC.