Science.gov

Sample records for 24-hour heart rate

  1. Aldosterone-to-Renin Ratio Is Associated With Reduced 24-Hour Heart Rate Variability and QTc Prolongation in Hypertensive Patients

    PubMed Central

    Grübler, Martin R.; Kienreich, Katharina; Gaksch, Martin; Verheyen, Nicolas; Hartaigh, Bríain Ó.; Fahrleitner-Pammer, Astrid; März, Winfried; Schmid, Johannes; Oberreither, Eva-Maria; Wetzel, Julia; Catena, Cristiana; Sechi, Leonardo A.; Pieske, Burkert; Tomaschitz, Andreas; Pilz, Stefan

    2016-01-01

    Abstract Aldosterone is considered to exert direct effects on the myocardium and the sympathetic nervous system. Both QT time and heart rate (HR) variability (HRV) are considered to be markers of arrhythmic risk and autonomous dysregulation. In this study, we investigated the associations between aldosterone, QT time, and HRV in patients with arterial hypertension. We recruited 477 hypertensive patients (age: 60.2 ± 10.2 years; 52.3% females) with a mean systolic/diastolic 24-hour ambulatory blood pressure monitoring (ABPM) value of 128 ± 12.8/77.1 ± 9.2 mmHg and with a median of 2 (IQR: 1–3) antihypertensive agents. Patients were recruited from the outpatient clinic at the Department of Internal Medicine of the Medical University of Graz, Austria. Blood samples, 24-hour HRV derived from 24-hour blood pressure monitoring (ABPM) and ECG's were obtained. Plasma aldosterone and plasma renin concentrations were measured by means of a radioimmunoassay. Twenty-four-hour urine specimens were collected in parallel with ABPM. Mean QTc was 423.3 ± 42.0 milliseconds for males and 434.7 ± 38.3 milliseconds for females. Mean 24H-HR and 24H-HRV was 71.9 ± 9.8 and 10.0 ± 3.6 bpm, respectively. In linear regression analyses adjusted for age, sex, body mass index, ABPM, and current medication, aldosterone to active renin ratio (AARR) was significantly associated with the QTc interval, a marker for cardiac repolarization abnormalities (mean = 426 ± 42.4 milliseconds; β-coefficient = 0.121; P = 0.03) as well as with the 24-hour heart rate variability a surrogate for autonomic dysfunction (median = 9.67 [IQR = 7.38–12.22 bpm]; β-coefficient = −0.133; P = 0.01). In hypertensive patients, AARR is significantly related to QTc prolongation as well as HRV. Further studies investigating the effects of mineralocorticoid receptor blocker and aldosterone synthase inhibitors on QTc and HRV are warranted

  2. Heart rate variability parameters of myxomatous mitral valve disease in dogs with and without heart failure obtained using 24-hour Holter electrocardiography.

    PubMed

    Oliveira, M S; Muzzi, R A L; Araújo, R B; Muzzi, L A L; Ferreira, D F; Nogueira, R; Silva, E F

    2012-06-16

    Time-domain heart rate variability (HRV) parameters and the correlation between echocardiography and Holter examinations in dogs with myxomatous mitral valve disease (MMVD) were determined. Holter examination was also performed at different time frames: an entire 24-hour period, a four-hour period during sleep, and a four-hour period while awake. Ten healthy (control group) and 28 MMVD dogs, 15 with and 13 without heart failure, were evaluated. The SDANN (sd of the mean normal RR intervals for all five-minute segments during 24-hour Holter) and pNN(50) (percentage of differences between adjacent normal RR intervals that are >50 ms computed over 24-hour Holter) variables were significantly lower in the dogs with MMVD heart failure. The differences in HRV between the groups were only detected during the 24-hour evaluation period (P<0.05). There were high correlations (canonical analysis) between Holter and echocardiography examinations when considering pNN(50), SDANN, and LA/AO (left atrial to aortic root ratio) (r=0.92; P<0.05), indicating that both are important in evaluating MMVD dogs. SDANN and pNN(50) are measures of parasympathetic control of the heart, and thus, it is possible to infer that the MMVD dogs exhibit parasympathetic withdrawal during the development of heart failure.

  3. Diurnal 24-hour rhythm in ambulatory heart rate variability during the day shift in rotating shift workers.

    PubMed

    Yoshizaki, Takahiro; Kawano, Yukari; Tada, Yuki; Hida, Azumi; Midorikawa, Toru; Hasegawa, Kohe; Mitani, Takeshi; Komatsu, Taiki; Togo, Fumiharu

    2013-06-01

    Circadian variation in cardiac autonomic nervous system activity and behavior during the day shifts of shift workers has not hitherto been clarified. This study examined diurnal 24-h variation in heart rate variability (HRV), sleep-wake cycle, physical activity, and food intake during the day shift in rotating shift workers. The subjects were female nurses and caregivers working at a health care facility (14 day workers and 13 rotating shift workers). Each subject was asked to undergo 24-h electrocardiograph and step count recordings. Coarse graining spectral analysis was used for approximately 10-min segments of HRV (600 beats) to derive the total power (TOT: >0.04 Hz), integrated power in the low-frequency (LF: 0.04-0.15 Hz) and high-frequency (HF: >0.15 Hz) ranges, the ratio of HF power to TOT (HF nu), and the ratio of LF power to HF power (LF/HF). Double cosinor analysis was used to obtain 24-h and 12-h period variations in variables of HRV and physical activity. While no difference was found in the acrophases of either period for step counts or in the 12-h period of HRV variables between the groups, the acrophases of the 24-h period for HRV variables were delayed by 1.3 to 5.5 h in rotating shift workers, and their differences in HF power, HF nu, and LF/HF reached a significant level (p < 0.05). On the days of the experiment, retiring time, waking up time, total time in bed, sleep efficiency, and mealtimes and energy intake for each diet did not differ between the groups. These results suggest that there is a possibility of an abnormal phase angle between circadian variation in cardiac autonomic nervous system activity and the sleep-wake cycle during the day shift in shift workers.

  4. Effects of Verapamil SR and Atenolol on 24-Hour Blood Pressure and Heart Rate in Hypertension Patients with Coronary Artery Disease: An International Verapamil SR-Trandolapril Ambulatory Monitoring Substudy

    PubMed Central

    Denardo, Scott J.; Gong, Yan; Cooper-DeHoff, Rhonda M.; Farsang, Csaba; Keltai, Matyas; Szirmai, László; Messerli, Franz H.; Bavry, Anthony A.; Handberg, Eileen M.; Mancia, Giuseppe; Pepine, Carl J.

    2015-01-01

    Elevated nighttime blood pressure (BP) and heart rate (HR), increased BP and HR variability, and altered diurnal variations of BP and HR (nighttime dipping and morning surge) in patients with systemic hypertension are each associated with increased adverse cardiovascular events. However, there are no reports on the effect of hypertension treatment on these important hemodynamic parameters in the growing population of hypertensive patients with atherosclerotic coronary artery disease (CAD). This was a pre-specified subgroup analysis of the INternational VErapamil SR-Trandolapril STudy (INVEST), which involved 22,576 clinically stable patients aged ≥50 years with hypertension and CAD randomized to either verapamil SR- or atenolol-based hypertension treatment strategies. The subgroup consisted of 117 patients undergoing 24-hour ambulatory monitoring at baseline and after 1 year of treatment. Hourly systolic and diastolic BP (SBP and DBP) decreased after 1 year for both verapamil SR- and atenolol-based treatment strategies compared with baseline (P<0.0001). Atenolol also decreased hourly HR (P<0.0001). Both treatment strategies decreased SBP variability (weighted standard deviation: P = 0.012 and 0.021, respectively). Compared with verapamil SR, atenolol also increased the prevalence of BP and HR nighttime dipping among prior non-dippers (BP: OR = 3.37; 95% CI: 1.26 – 8.97; P = 0.015; HR: OR = 4.06; 95% CI: 1.35-12.17; P = 0.012) and blunted HR morning surge (+2.8 vs. +4.5 beats/min/hr; P = 0.019). Both verapamil SR- and especially atenolol-based strategies resulted in favorable changes in ambulatory monitoring parameters that have been previously associated with increased adverse cardiovascular events. Trial Registration Clinicaltrials.gov; NCT00133692 PMID:25835002

  5. Tolvaptan Prolongs Blockage of the Vasopressin Type II Receptor Over 24 Hours in Responders With Stage D Heart Failure.

    PubMed

    Imamura, Teruhiko; Kinugawa, Koichiro; Komuro, Issei

    2016-01-01

    The urine aquaporin-2 (U-AQP2) level relative to the plasma arginine vasopressin (P-AVP) level is a novel predictor of the responsiveness to the vasopressin type 2 receptor (V2R) antagonist tolvaptan (TLV). However, little has been reported about the concentration-time profile of U-AQP2 after TLV treatment. We evaluated 24 patients with decompensated stage D heart failure (HF) who had received 3.75 mg/day of TLV on a de novo basis for > 7 days to treat congestion refractory to conventional diuretics. Seventeen patients were TLV-responders, whose 24-hour urine volume (UV) increased after TLV initiation; the other 7 patients were TLV-non-responders. The U-AQP2 of the TLV-responders, corrected for the urine creatinine concentration, decreased significantly at 4 hours after TLV administration without returning to the day-1 morning level on the morning of day-7. The TLV-non-responder U-AQP2 levels remained low even before the TLV treatment. On the morning of day-7, the TLV-responder U-AQP2/P-AVP ratio was comparable to that of the TLV-non-responders. Among 18 patients (11 responders and 7 non-responders), the day-7 TLV trough concentration was 64 ± 62 ng/mL and was negatively correlated with the estimated glomerular filtration rate (eGFR). TLV has antagonistic effects on the V2R over 24 hours in TLV-responders with advanced heart failure and chronic kidney disease, probably due to persistently elevated blood TLV concentration. The unresponsiveness to TLV in the TLV-non-responders is not attributable to malabsorption. PMID:26742881

  6. [Individual peculiarities of adaptation to long-term space flights: 24-hour heart rhythm monitoring

    NASA Technical Reports Server (NTRS)

    Baevskii, R. M.; Bogomolov, V. V.; Gol'dberger, A. L.; Nikulina, G. A.; Charl'z, D. B.; Goldberger, A. L. (Principal Investigator); Charles, J. B. (Principal Investigator)

    2000-01-01

    Presented are results of studying 24-hr variability of the cardiac rhythm which characterizes individual difference in reactions of two crew members to the same set of stresses during a 115-day MIR mission. Spacelab (USA) cardiorecorders were used. Data of monitoring revealed significantly different baseline health statuses of the cosmonauts. These functional differences were also observed in the mission. In one of the cosmonauts, the cardiac regulation changed over to a more economic functioning with the autonomous balance shifted towards enhanced sympathetic activity. After 2-3 months on mission he had almost recovered pre-launch level of regulation. In the other, the regulatory system was appreciably strained at the beginning of the mission as compared with preflight baseline. Later on, on flight months 2-3, this strain kept growing till a drastic depletion of the functional reserve. On return to Earth, this was manifested by a strong stress reaction with a sharp decline in power of high-frequency and grow in power of very low frequency components of the heart rhythm. The data suggest that adaptation to space flight and reactions in the readaptation period are dependent on initial health status of crew members, and functional reserve.

  7. [The incidence of arrhythmias in young persons without demonstrable heart disease: a 24-hour Holter study in 100 medical students].

    PubMed

    Berrazueta, J R; Poveda, J J; Puebla, F; Salas, E; Ochoteco, A; Gutiérrez, N

    1993-03-01

    A Holter monitorization study was performed in 100 voluntary university students (64 men and 36 women). The mean age was 23.6 years and organic heart disease was ruled out in all cases. Data were analysed in different subgroups including the practice of physical activity and subjects smokers or alcohol consumers. The maximum heart rate (HR) achieved during the wake period was 138.3 +/- 20.43 beat/m. Minimum daytime heart rate was 61.42 +/- 10.32 beat/m and it was below 60 beat/m in 41 subjects. During the nighttime period, the maximum heart rate achieved by the group was 89.34 +/- 11.31 beat/m. Minimum nighttime heart rate was 45.82 +/- 6.35 beat/m. Maximum heart rate in men was 134.3 +/- 21.35 beat/m, while in women was 145.42 +/- 16.36 beat/m. Eighty students presented one or more arrhythmias, among them 28 women and 52 men (p = NS): 92% in sportsmen and women groups as compared with 79% in the non sports practicers, 90% of alcohol consumers and 82% between subjects who smoked and drank, compared with 63% in the non drinkers (p < 0.006). 48% of the subjects presented one or more supraventricular arrhythmias during the daytime or during the nighttime (p = NS). Ventricular rhythm disturbances were found in 20 subjects. There was only one case who had a non sustained ventricular tachycardia of 4 complexes. These disturbances were not increased by practising sport nor by toxic habits. In 15 cases we found sinoatrial block, with a male predominance. Five subjects presented some type of atrioventricular block, 4 of which were alcohol and tobacco consumers.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Adrenal catecholamine synthesis rate changes induced by combined thermal and immobilization stress in fed and 24 hour fasted rats.

    PubMed

    Bargiel, Z; Nowicka, H

    1989-01-01

    The combined stress of acute immobilization (IM) at high and low ambient temperature has been used to determine its influence on adrenal catecholamine (CA) content assassed histofluorimetrically in fed and 24 hour fasted rats. The general course of changes obtained after the arrangement of adrenal strips deriving from the adrenals of rats exposed to cold and IM stress (CIMS) at +10 degrees C to -25 degrees C during the different time fragments presented the adrenal CA depletion events followed sometimes by the adrenal CA content increase after the longer stress exposure or/and stronger CIMS and WIMS conditions. It was found that this depletion-stimulated increase of adrenal Ca synthesis rate had been accelerated in 24 h fasted rats compared to satiated ones exposed to the same stress conditions, especially after the CIMS exposure. Moreover the survival time duration at first lethal temperature (-5 degrees C and +45 degrees C) was significantly higher in fasted rats. The possible hypothalamic regulation of adrenal CA synthesis rate accordingly to the actual metabolism needs and beta-adrenoceptor sensitivity changes depending on satiety state have been discussed and the necessity of further investigations concerning the specificity of stress-induced metabolism changes in 24 h starved rats has been suggested.

  9. Risk Stratification by 24-Hour Ambulatory Blood Pressure and Estimated Glomerular Filtration Rate in 5322 Subjects From 11 Populations

    PubMed Central

    Boggia, José; Thijs, Lutgarde; Li, Yan; Hansen, Tine W.; Kikuya, Masahiro; Björklund-Bodegård, Kristina; Ohkubo, Takayoshi; Jeppesen, Jørgen; Torp-Pedersen, Christian; Dolan, Eamon; Kuznetsova, Tatiana; Stolarz-Skrzypek, Katarzyna; Tikhonoff, Valérie; Malyutina, Sofia; Casiglia, Edoardo; Nikitin, Yuri; Lind, Lars; Schwedt, Emma; Sandoya, Edgardo; Kawecka-Jaszcz, Kalina; Filipovský, Jan; Imai, Yutaka; Wang, Jiguang; Ibsen, Hans; O’Brien, Eoin; Staessen, Jan A.

    2013-01-01

    No previous study addressed whether in the general population estimated glomerular filtration rate (eGFR [Chronic Kidney Disease Epidemiology Collaboration formula]) adds to the prediction of cardiovascular outcome over and beyond ambulatory blood pressure. We recorded health outcomes in 5322 subjects (median age, 51.8 years; 43.1% women) randomly recruited from 11 populations, who had baseline measurements of 24-hour ambulatory blood pressure (ABP24) and eGFR. We computed hazard ratios using multivariable-adjusted Cox regression. Median follow-up was 9.3 years. In fully adjusted models, which included both ABP24 and eGFR, ABP24 predicted (P≤0.008) both total (513 deaths) and cardiovascular (206) mortality; eGFR only predicted cardiovascular mortality (P=0.012). Furthermore, ABP24 predicted (P≤0.0056) fatal combined with nonfatal events as a result of all cardiovascular causes (555 events), cardiac disease (335 events), or stroke (218 events), whereas eGFR only predicted the composite cardiovascular end point and stroke (P≤0.035). The interaction terms between ABP24 and eGFR were all nonsignificant (P≥0.082). For cardiovascular mortality, the composite cardiovascular end point, and stroke, ABP24 added 0.35%, 1.17%, and 1.00% to the risk already explained by cohort, sex, age, body mass index, smoking and drinking, previous cardiovascular disease, diabetes mellitus, and antihypertensive drug treatment. Adding eGFR explained an additional 0.13%, 0.09%, and 0.14%, respectively. Sensitivity analyses stratified for ethnicity, sex, and the presence of hypertension or chronic kidney disease (eGFR <60 mL/min per 1.73 m2) were confirmatory. In conclusion, in the general population, eGFR predicts fewer end points than ABP24. Relative to ABP24, eGFR is as an additive, not a multiplicative, risk factor and refines risk stratification 2- to 14-fold less. PMID:23172928

  10. The effect of low level radiofrequency electromagnetic radiation on the excretion rates of stress hormones in operators during 24-hour shifts.

    PubMed

    Vangelova, K; Israel, M; Mihaylov, S

    2002-06-01

    The aim of the study was to investigate the effect of long term exposure to low level radiofrequency (RF) electromagnetic (EM) radiation on the excretion rates of stress hormones in satellite station operators during 24-hour shifts. Twelve male operators at a satellite station for TV communications and space research were studied during 24-hour shifts. Dosimetric evaluation of the exposure was carried out and showed low level exposure with specific absorption of 0.1127 J.kg-1. A control group of 12 unexposed male operators with similar job task and the same shift system were studied, too. The 11-oxycorticosteroids (11-OCS), adrenaline and noradrenaline were followed by spectrofluorimetric methods on 3-hour intervals during the 24-hour shifts. The data were analyzed by tests for interindividual analysis, Cosinor analysis and analysis of variance (ANOVA). Significant increase in the 24-hour excretion of 11-OCS and disorders in its circadian rhythm, manifested by increase in the mesor, decrease in the amplitude and shift in the acrophase were found in the exposed operators. The changes in the excretion rates of the catecholamines were significant and showed greater variability of both variables. The long term effect of the exposure to low-level RF EM radiation evoked pronounced stress reaction with changes in the circadian rhythm of 11-OCS and increased variability of catecholamines secretion. The possible health hazards associated with observed alteration in the stress system need to be clarified by identification of their significance and prognostic relevance.

  11. [Music and heart rate variability. Study of the effect of music on heart rate variability in healthy adolescents].

    PubMed

    Escher, J; Evéquoz, D

    1999-05-20

    The effect of trophotropic (relaxing) music on heart rate and heart rate variability has been investigated in 23 healthy young individuals by means of 24-hour Holter-ECG. Relaxing music (Bach, Vivaldi, Mozart) resulted in significant reduction of heart rate and also significant reduction of heart rate variability. The significance of these results for the use of music in coronary heart disease is discussed.

  12. 24-Hour Relativistic Bit Commitment

    NASA Astrophysics Data System (ADS)

    Verbanis, Ephanielle; Martin, Anthony; Houlmann, Raphaël; Boso, Gianluca; Bussières, Félix; Zbinden, Hugo

    2016-09-01

    Bit commitment is a fundamental cryptographic primitive in which a party wishes to commit a secret bit to another party. Perfect security between mistrustful parties is unfortunately impossible to achieve through the asynchronous exchange of classical and quantum messages. Perfect security can nonetheless be achieved if each party splits into two agents exchanging classical information at times and locations satisfying strict relativistic constraints. A relativistic multiround protocol to achieve this was previously proposed and used to implement a 2-millisecond commitment time. Much longer durations were initially thought to be insecure, but recent theoretical progress showed that this is not so. In this Letter, we report on the implementation of a 24-hour bit commitment solely based on timed high-speed optical communication and fast data processing, with all agents located within the city of Geneva. This duration is more than 6 orders of magnitude longer than before, and we argue that it could be extended to one year and allow much more flexibility on the locations of the agents. Our implementation offers a practical and viable solution for use in applications such as digital signatures, secure voting and honesty-preserving auctions.

  13. 24-Hour Academic Libraries: Adjusting to Change

    ERIC Educational Resources Information Center

    Bowman, Adam C.

    2013-01-01

    The purpose of this study was to explore the adaptive measures that academic libraries perform when implementing and operating a 24-hour schedule. Five in-depth interviews were conducted with current managerial-level librarians at 24-hour academic libraries. The exploratory interviews revealed similar measures for security, budgeting, employee…

  14. Target Heart Rate Calculator

    MedlinePlus

    ... My Saved Articles » My ACS » + - Text Size Target Heart Rate Calculator Compute your best workout Enter your age ... is your age? years. How to Check Your Heart Rate Right after you stop exercising, take your pulse: ...

  15. The 24-Hour Mathematical Modeling Challenge

    ERIC Educational Resources Information Center

    Galluzzo, Benjamin J.; Wendt, Theodore J.

    2015-01-01

    Across the mathematics curriculum there is a renewed emphasis on applications of mathematics and on mathematical modeling. Providing students with modeling experiences beyond the ordinary classroom setting remains a challenge, however. In this article, we describe the 24-hour Mathematical Modeling Challenge, an extracurricular event that exposes…

  16. A 24-HOUR AMBULATORY ECG MONITORING IN ASSESSMENT OF QT INTERVAL DURATION AND DISPERSION IN ROWERS WITH PHYSIOLOGICAL MYOCARDIAL HYPERTROPHY

    PubMed Central

    Kim, Z.F.; Bilalova, R.R.; Tsibulkin, N.A.; Almetova, R.R.; Mudarisova, R.R.; Ahmetov, I.I.

    2013-01-01

    Myocardial hypertrophy (MH) due to cardiac pathology is characterized by an increase in QT interval duration and dispersion, while the findings for exercise-induced myocardial hypertrophy are contradictory. The majority of published research findings have not explored this relationship, but there have only been a few conducted studies using 24-hour ECG monitoring. The aim of the study was to determine the QT interval duration and dispersion in short-term and 24-hour ECG in endurance athletes with myocardial hypertrophy and without it. Methods: A total of 26 well-trained rowers underwent a resting 12-lead ECG, 24-hour ECG monitoring and echocardiography. Results: Athletes with MH (n = 7) at rest did not show any increase in QTc interval duration and dispersion, or mean and maximal QTc duration in Holter monitoring compared to athletes without MH (n = 19). Left ventricular mass was not significantly correlated with any QTc characteristics. Furthermore, athletes with MH had significantly longer mean QT (P = 0.01) and maximal QT (P = 0.018) intervals in Holter monitoring and higher 24-hour heart rate variability indexes due to stronger vagal effects. Conclusions: The present study demonstrated that athlete's heart syndrome with myocardial hypertrophy as a benign phenomenon does not lead to an increase in QT interval duration, or increases in maximal and mean duration in a 24-hour ECG. An increase in QT interval duration in athletes may have an autonomic nature. PMID:24744494

  17. Effects of different training amplitudes on heart rate and heart rate variability in young rowers.

    PubMed

    Vaz, Marcelo S; Picanço, Luan M; Del Vecchio, Fabrício B

    2014-10-01

    The aim of this study was to investigate the autonomic nervous system recovery and the psychological response as a result of 3 training amplitudes on heart rate (HR), heart rate variability (HRV), and rate of perceived exertion (RPE) in rowing. Eight young rowers (16.8 ± 1.4 years) performed, in a randomized fashion, 2 sessions of high-intensity interval training, with high and low amplitude and a continuous training (CT) session, with the same exercise duration (10 minutes) and mean intensity (60% of maximal stroke test). The data of HR, HRV, and RPE were collected 5 minutes before, immediately after each session, and 24 hours later. High amplitude promoted higher impact in maximum HR (p ≤ 0.05) and RPE (p < 0.001) when compared with CT. For the time domain HRV variable, there was a statistically significant difference between moments of rest (pretraining or post 24 hours) and posttraining in all training sessions. Originally, we conclude that training with higher load variation between effort and recovery impacts HRV, HR, and RPE with greater intensity, but the younger rowers were ready for new training sessions 24 hours after either training method. Coaches can use the polarized training method, observing the stimulus nature and time required for recovery, because it may be an adequate strategy for the development of rower's conditioning. PMID:24736775

  18. Seasonal changes of 24-hour intraocular pressure rhythm in healthy Shanghai population

    PubMed Central

    Cheng, Jingyi; Xiao, Ming; Xu, Huan; Fang, Shaobin; Chen, Xu; Kong, Xiangmei; Sun, Xinghuai

    2016-01-01

    Abstract The aim of the present study was to investigate and compare the 24-hour intraocular pressure (IOP) rhythms in winter and summer in the healthy population of Shanghai, China. This is a cross-sectional study in which 24-hour IOP measurements were taken for all eligible healthy volunteers in winter and summer, respectively, and the temperature, hours of sunlight (sunlight time), and circulatory parameters, including heart rate, systolic blood pressure, and diastolic blood pressure, were also recorded. The 24-hour IOP curves and IOP parameters (mean, peak, trough, and fluctuation of IOP together with the diurnal-to-nocturnal IOP change) in winter and summer were obtained and compared. The magnitude of IOP changes from summer to winter was also calculated. A total of 29 participants (58 eyes), 14 (48.28%) male and 15 (51.72%) female, aged 43.66 ± 12.20 (19–61) years, were considered eligible for this study. Generally, IOP decreased progressively before noon, increased notably in the nocturnal period, and peaked at 12:00 am in winter and at 2:00 am in summer. The pattern of 24-hour IOP in winter and summer was significantly different (P = 0.002). The average IOPs from 4:00 pm to 8:00 am, except for 6:00 am, were significantly higher in winter (P < 0.05). However, no significant differences were shown after adjusting for temperature and/or sunlight time. From summer to winter, the extent of IOP increase was mostly around 0 to 3 mm Hg, and the IOPs increased more significantly in the nocturnal period than in the diurnal period (P = 0.05). The 24-hour IOP rhythms were different in winter and summer, with higher IOP level in winter. Temperature and sunlight time, which are independent of heart rate and blood pressure, affected the 24-hour IOP rhythms in healthy people in Shanghai, China. Further investigations are expected for the rhythm of some endogenous substance secretion and the inner mechanism of regulation of IOP. PMID:27495076

  19. Heart Rate Monitors

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

  20. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death.

  1. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death. PMID:24215748

  2. Heart Rate Monitor

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the mid 70's, NASA saw a need for a long term electrocardiographic electrode suitable for use on astronauts. Heart Rate Inc.'s insulated capacitive electrode is constructed of thin dielectric film applied to stainless steel surface, originally developed under a grant by Texas Technical University. HRI, Inc. was awarded NASA license and continued development of heart rate monitor for use on exercise machines for physical fitness and medical markets.

  3. Modelling heart rate kinetics.

    PubMed

    Zakynthinaki, Maria S

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual's cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women).

  4. Modelling Heart Rate Kinetics

    PubMed Central

    Zakynthinaki, Maria S.

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual’s cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  5. [Electrocardiographic recording of long duration (Holter) of 24 hours during idiopathic cardiomyopathy of the peripartum].

    PubMed

    Diao, M; Diop, I B; Kane, A; Camara, S; Kane, Ad; Sarr, M; Ba, S A; Diouf, S M

    2004-01-01

    The idiopathic myocardiopathy of the peripartum (IMPP) is a frequent disease in the Soudano-Sahelian zone of Africa whose evolution is loaded with many complications hemodynamic, thrombo-embolic and rhythmic. The prevalence and the meaning of the rhythm disorders are unknown. The aims of this prospective study are to measure and to describe the prevalence of the anomalies observed in Holter ECG of 24 hours. It's about a description cross-sectional study realized at the Cardiology Department (CHU Dakar) and 19 patients with IMPP were included, from October 2000 to July 2002. A recording ECG of 24 hours (Holter) was realized on all the patients. The average age was 29.4+/-6.9 years with a low socio-economic level (100%). The diagnosis of IMPP done before childbirth in 4 cases (21%) and the post partum on 15 patients (78.9%). The dyspnea was constant, the chest pain in 12 cases (63.1%) and palpitations in 8 cases (42%). The average rate of hemoglobin was of 10.85+/-2.05 g/dL. The standard electrocardiogram recorded a sinusal tachycardia (68.4%), a cavitary hypertrophy (78.8%), and disorders of the repolarization (47.3%). The cardiac echo-Doppler noted a cavitary dilatation (84.2%), a constant alteration of the left ventricular systolic function with a fraction of average ejection of 29.7+/-10.3%. The anatomy of the valves was normal. The recording Holter ECG of 24 hours recorded a sinusal tachycardia in 17 cases (89.4%), ventricular extrasystoles on 7 patients (36.8%), 4 cases of ventricular tachycardia non-sustained and double ventricular extrasystole on 1 patient, auricular extrasystoles in 4 cases (21%) and 1 case of auriculo-ventricular block of the first degree. The study of heart rate variability founded a mean value of 106 ms.

  6. Development of an artificial placenta IV: 24 hour venovenous extracorporeal life support in premature lambs.

    PubMed

    Gray, Brian W; El-Sabbagh, Ahmed; Rojas-Pena, Alvaro; Kim, Anne C; Gadepali, Samir; Koch, Kely L; Capizzani, Tony R; Bartlet, Robert H; Mychaliska, George B

    2012-01-01

    An extracorporeal artificial placenta would change the paradigm of treating extremely premature infants. We hypothesized that a venovenous extracorporeal life support (VV-ECLS) artificial placenta would maintain fetal circulation, hemodynamic stability, and adequate gas exchange for 24 hours. A near-term neonatal lamb model (130 days; term = 145 days) was used (n = 9). The right jugular vein was cannulated for VV-ECLS outflow, and an umbilical vein was used for inflow. The circuit included a peristaltic roller pump and a 0.5 m(2) hollow fiber oxygenator. Lambs were maintained on VV-ECLS in an "amniotic bath" for up to 24 hours. Five of nine fetuses survived for 24 hours. In the survivors, average mean arterial pressure was 69 ± 10 mm Hg for the first 4 hours and 36 ± 8 mm Hg for the remaining 20 hours. The mean fetal heart rate was 202 ± 30. Mean VV-ECLS flow was 94 ± 20 ml/kg/min. Using a gas mixture of 50% O(2)/3% CO(2) and sweep flow of 1-2 L/min, the mean pH was 7.27 ± 0.09, with Po(2) of 35 ± 12 mm Hg and Pco(2) of 48 ± 12 mm Hg. Necropsy revealed a patent ductus arteriosus in all cases, and there was no gross or microscopic intracranial hemorrhage. Complications in failed attempts included technically difficult cannulation and multisystem organ failure. Future studies will enhance stability and address the factors necessary for long-term support.

  7. Heart rate variability in isolated rabbit hearts.

    PubMed

    Frey, B; Heger, G; Mayer, C; Kiegler, B; Stöhr, H; Steurer, G

    1996-11-01

    The presence of heart rate variability (HRV) in patients with cardiac denervation after heart transplantation raised our interest in HRV of isolated, denervated hearts. Hearts from seven adult white ELCO rabbits were transferred to a perfusion apparatus. All hearts were perfused in the working mode and in the Langendorff mode for 20 minutes each. HRV was analyzed in the frequency domain. A computer simulated test ECG at a constant rate of 2 Hz was used for error estimation of the system. In the isolated, denervated heart, HRV was of random, broadband fluctuations, different from the well-characterized oscillations at specific frequencies in intact animals. Mean NN was 423 +/- 51 ms in the Langendorff mode, 406 +/- 33 ms in the working heart mode, and 500 ms in the test ECG. Total power was 663 +/- 207 ms2, 817 +/- 318 ms2, and 3.7 ms2, respectively. There was no significant difference in any measure of HRV between Langendorff and working heart modes. The data provide evidence for the presence of HRV in isolated, denervated rabbit hearts. Left atrial and ventricular filling, i.e., the working heart mode, did not alter HRV, indicating that left atrial or ventricular stretch did not influence the sinus nodal discharge rate.

  8. The 24-hour pulse wave velocity, aortic augmentation index, and central blood pressure in normotensive volunteers.

    PubMed

    Kuznetsova, Tatyana Y; Korneva, Viktoria A; Bryantseva, Evgeniya N; Barkan, Vitaliy S; Orlov, Artemy V; Posokhov, Igor N; Rogoza, Anatoly N

    2014-01-01

    The purpose of this study was to examine the pulse wave velocity, aortic augmentation index corrected for heart rate 75 (AIx@75), and central systolic and diastolic blood pressure during 24-hour monitoring in normotensive volunteers. Overall, 467 subjects (206 men and 261 women) were recruited in this study. Participants were excluded from the study if they were less than 19 years of age, had blood test abnormalities, had a body mass index greater than 2 7.5 kg/m(2), had impaired glucose tolerance, or had hypotension or hypertension. Ambulatory blood pressure monitoring (ABPM) with the BPLab(®) device was performed in each subject. ABPM waveforms were analyzed using the special automatic Vasotens(®) algorithm, which allows the calculation of pulse wave velocity, AIx@75, central systolic and diastolic blood pressure for "24-hour", "awake", and "asleep" periods. Circadian rhythms and sex differences in these indexes were identified. Pending further validation in prospective outcome-based studies, our data may be used as preliminary diagnostic values for the BPLab ABPM additional index in adult subjects.

  9. The 24-hour pulse wave velocity, aortic augmentation index, and central blood pressure in normotensive volunteers.

    PubMed

    Kuznetsova, Tatyana Y; Korneva, Viktoria A; Bryantseva, Evgeniya N; Barkan, Vitaliy S; Orlov, Artemy V; Posokhov, Igor N; Rogoza, Anatoly N

    2014-01-01

    The purpose of this study was to examine the pulse wave velocity, aortic augmentation index corrected for heart rate 75 (AIx@75), and central systolic and diastolic blood pressure during 24-hour monitoring in normotensive volunteers. Overall, 467 subjects (206 men and 261 women) were recruited in this study. Participants were excluded from the study if they were less than 19 years of age, had blood test abnormalities, had a body mass index greater than 2 7.5 kg/m(2), had impaired glucose tolerance, or had hypotension or hypertension. Ambulatory blood pressure monitoring (ABPM) with the BPLab(®) device was performed in each subject. ABPM waveforms were analyzed using the special automatic Vasotens(®) algorithm, which allows the calculation of pulse wave velocity, AIx@75, central systolic and diastolic blood pressure for "24-hour", "awake", and "asleep" periods. Circadian rhythms and sex differences in these indexes were identified. Pending further validation in prospective outcome-based studies, our data may be used as preliminary diagnostic values for the BPLab ABPM additional index in adult subjects. PMID:24812515

  10. All about Heart Rate (Pulse)

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More All About Heart Rate (Pulse) Updated:Apr 19,2016 ... Sodium and Salt 3 Low Blood Pressure 4 All About Heart Rate (Pulse) 5 How to Eat ...

  11. Nutritional behavior of cyclists during a 24-hour team relay race: a field study report

    PubMed Central

    2012-01-01

    Background Information about behavior of energy intake in ultra-endurance cyclists during a 24-hour team relay race is scarce. The nutritional strategy during such an event is an important factor which athletes should plan carefully before the race. The purpose of this study was to examine and compare the nutritional intake of ultra-endurance cyclists during a 24-hour team relay race with the current nutritional guidelines for endurance events. Additionally, we analyzed the relationship among the nutritional and performance variables. Methods Using a observational design, nutritional intake of eight males (mean ± SD: 36.7 ± 4.7 years; 71.6 ± 4.9 kg; 174.6 ± 7.3 cm; BMI 23.5 ± 0.5 kg/m2) participating in a 24-hour team relay cycling race was assessed. All food and fluid intake by athletes were weighed and recorded. Additionally, distance and speed performed by each rider were also recorded. Furthermore, before to the race, all subjects carried out an incremental exercise test to determine two heart rate-VO2 regression equations which were used to estimate the energy expenditure. Results The mean ingestion of macronutrients during the event was 943 ± 245 g (13.1 ± 4.0 g/kg) of carbohydrates, 174 ± 146 g (2.4 ± 1.9 g/kg) of proteins and 107 ± 56 g (1.5 ± 0.7 g/kg) of lipids, respectively. This amount of nutrients reported an average nutrient intake of 22.8 ± 8.9 MJ which were significantly lower compared with energy expenditure 42.9 ± 6.8 MJ (P = 0.012). Average fluid consumption corresponded to 10497 ± 2654 mL. Mean caffeine ingestion was 142 ± 76 mg. Additionally, there was no relationship between the main nutritional variables (i.e. energy intake, carbohydrates, proteins, fluids and caffeine ingestion) and the main performance variables (i.e. distance and speed). Conclusions A 24-hour hours cycling competition in a team relay format elicited high energy demands which were not compensated by energy intake of the athletes despite that dietary

  12. Human prolactin - 24-hour pattern with increased release during sleep.

    NASA Technical Reports Server (NTRS)

    Sassin, J. F.; Weitzman, E. D.; Kapen, S.; Frantz, A. G.

    1972-01-01

    Human prolactin was measured in plasma by radioimmunoassay at 20-minute intervals for a 24-hour period in each of six normal adults, whose sleep-wake cycles were monitored polygraphically. A marked diurnal variation in plasma concentrations was demonstrated, with highest values during sleep. Periods of episodic release occurred throughout the 24 hours.

  13. Coefficient of Variation of Coarsely Sampled Heart Rate Is Associated with Early Vasopressor Independence in Severe Sepsis and Septic Shock

    PubMed Central

    Brown, Samuel M.; Tate, M. Quinn; Jones, Jason P.; Kuttler, Kathryn G.; Lanspa, Michael; Rondina, Matthew T.; Grissom, Colin K.; Mathews, V.J.

    2014-01-01

    Purpose Determine whether variability of coarsely sample heart rate and blood pressure early in the course of severe sepsis and septic shock predicts successful resuscitation, defined as vasopressor independence at 24 hours after admission. Methods In an observational study of patients admitted with severe sepsis or septic shock from 2009 to 2011 to one of two ICUs at a tertiary-care hospital, in whom blood pressure was measured via an arterial catheter, we sampled heart rate and blood pressure every 30 seconds over the first six hours of ICU admission and calculated coefficient of variability of those measurements. Primary outcome was vasopressor independence at 24 hours; secondary outcome was 28-day mortality. Results We studied 165 patients, of which 97 (59%) achieved vasopressor independence at 24 hours. Overall 28-day mortality was 15%. Significant predictors of vasopressor independence at 24 hours included the coefficient of variation of heart rate, age, APACHE II, the number of increases in vasopressor dose, mean vasopressin dose, mean blood pressure, and time-pressure integral of mean blood pressure below 60mm Hg. Lower sampling frequencies (up to once every 5 minutes) did not affect the findings. Conclusions Increased variability of coarsely sampled heart rate was associated with vasopressor independence at 24 hours after controlling for possible confounders. Sampling frequencies of once in five minutes may be similar to once in 30 seconds. PMID:24578465

  14. High energy deficit in an ultraendurance athlete in a 24-hour ultracycling race

    PubMed Central

    Rodríguez, Ferran A.; Iglesias, Xavier; Benítez, Adolfo; Marina, Míchel; Padullés, Josep M.; Torrado, Priscila; Vázquez, Jairo; Knechtle, Beat

    2012-01-01

    This case study examined the nutritional behavior and energy balance in an official finisher of a 24-hour ultracycling race. The food and beverages consumed by the cyclist were continuously weighed and recorded to estimate intake of energy, macronutrients, sodium, and caffeine. In addition, during the race, heart rate was continuously monitored. Energy expenditure was assessed using a heart rate–oxygen uptake regression equation obtained previously from a laboratory test. The athlete (39 years, 175.6 cm, 84.2 kg, maximum oxygen uptake, 64 mL/kg/min) cycled during 22 h 22 min, in which he completed 557.3 km with 8760 m of altitude at an average speed of 25.1 km/h. The average heart rate was 131 beats/min. Carbohydrates were the main macronutrient intake (1102 g, 13.1 g/kg); however, intake was below current recommendations. The consumption of protein and fat was 86 g and 91 g, respectively. He ingested 20.7 L (862 mL/h) of fluids, with sport drinks the main fluid used for hydration. Sodium concentration in relation to total fluid intake was 34.0 mmol/L. Caffeine consumption over the race was 231 mg (2.7 mg/kg). During the race, he expended 15,533 kcal. Total energy intake was 5571 kcal, with 4058 (73%) and 1513 (27%) kcal derived from solids and fluids, respectively. The energy balance resulted in an energy deficit of 9915 kcal. PMID:22481841

  15. Tachycardia | Fast Heart Rate

    MedlinePlus

    ... Prevention & Treatment of High Blood Pressure High Blood Pressure Tools & Resources ... signals in the heart's upper chambers fire abnormally, which interferes with electrical signals coming from ...

  16. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  17. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  18. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  19. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  20. 29 CFR 785.21 - Less than 24-hour duty.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... be on duty for less than 24 hours is working even though he is permitted to sleep or engage in other... specified hours is working even though she is permitted to sleep when not busy answering calls. It makes...

  1. Extended duration orbiter medical project variability of blood pressure and heart rate (STS-50/USML-1)

    NASA Technical Reports Server (NTRS)

    Fritsch-Yelle, Janice M.; Charles, John B.; Boettcher, Sheila W.

    1994-01-01

    Decreases in arterial baroreflex function after space flight may be related to changes in blood pressure and heart rate patterns during flight. Ambulatory blood pressure and heart rate were measured for 24 hours, in fourteen astronauts on two occasions before flight, two to three occasions in flight, and 2 days after landing on Shuttle missions lasting 4 to 14 days. Blood pressure and heart rate were recorded every 20minutes during awake periods and every 30 minutes during sleep. In pre- and postflight studies, the 24-hour ambulatory measurements were followed by studies of carotid baroreceptor-cardiac reflex responses. Carotid baroreceptors were stimulated using a sequence of neck pressure and suction from +40 to -65 mmHg.

  2. Analysis of long term heart rate variability: methods, 1/f scaling and implications

    NASA Technical Reports Server (NTRS)

    Saul, J. P.; Albrecht, P.; Berger, R. D.; Cohen, R. J.

    1988-01-01

    The use of spectral techniques to quantify short term heart rate fluctuations on the order of seconds to minutes has helped define the autonomic contributions to beat-to-beat control of heart rate. We used similar techniques to quantify the entire spectrum (0.00003-1.0 Hz) of heart rate variability during 24 hour ambulatory ECG monitoring. The ECG from standard Holter monitor recordings from normal subjects was sampled with the use of a phase locked loop, and a heart rate time series was constructed at 3 Hz. Frequency analysis of the heart rate signal was performed after a nonlinear filtering algorithm was used to eliminate artifacts. A power spectrum of the entire 24 hour record revealed power that was inversely proportional to frequency, 1/f, over 4 decades from 0.00003 to 0.1 Hz (period approximately 10 hours to 10 seconds). Displaying consecutive spectra calculated at 5 minute intervals revealed marked variability in the peaks at all frequencies throughout the 24 hours, probably accounting for the lack of distinct peaks in the spectra of the entire records.

  3. Target Heart Rates

    MedlinePlus

    ... a Healthy Heart Healthy Kids Our Kids Programs Childhood Obesity What is childhood obesity? Overweight in Children BMI in Children Is Childhood Obesity an Issue in Your Home? Addressing your Child's ...

  4. Ambulatory arterial stiffness index derived from 24-hour ambulatory blood pressure monitoring.

    PubMed

    Li, Yan; Wang, Ji-Guang; Dolan, Eamon; Gao, Ping-Jin; Guo, Hui-Feng; Nawrot, Tim; Stanton, Alice V; Zhu, Ding-Liang; O'Brien, Eoin; Staessen, Jan A

    2006-03-01

    We hypothesized that 1 minus the slope of diastolic on systolic pressure during 24-hour ambulatory monitoring (ambulatory arterial stiffness index [AASI]) might reflect arterial stiffness. We compared AASI with established measures of arterial stiffness and studied its distribution in Chinese and European populations. We used 90207 SpaceLabs monitors and the SphygmoCor device to measure AASI, central and peripheral pulse pressures, the central (CAIx) and peripheral (PAIx) systolic augmentation indexes, and aortic pulse wave velocity. In 166 volunteers, the correlation coefficient between AASI and pulse wave velocity was 0.51 (P<0.0001). In 348 randomly recruited Chinese subjects, AASI correlated (P<0.0001) with CAIx (r=0.48), PAIx (r=0.50), and central pulse pressure (r=0.50). AASI increased with age and mean arterial pressure but decreased with body height. Both before and after adjustment for arterial wave reflections by considering height and heart rate as covariates, AASI correlated more (P<0.0001) closely with CAIx and PAIx than 24-hour pulse pressure. Among normotensive subjects, the 95th percentile of AASI was 0.55 in Chinese and 0.57 in 1617 Europeans enrolled in the International Database on Ambulatory Blood Pressure Monitoring. The upper boundary of the 95% prediction interval of AASI in relation to age ranged from 0.53 at 20 years to 0.72 at 80 years. In conclusion, AASI is a new index of arterial stiffness that can be easily measured under ambulatory conditions. Pending additional validation in outcome studies, normal values of AASI are probably <0.50 and 0.70 in young and older subjects, respectively. PMID:16432048

  5. Heart rate dynamics preceding hemorrhage in the intensive care unit.

    PubMed

    Moss, Travis J; Clark, Matthew T; Lake, Douglas E; Moorman, J Randall; Calland, J Forrest

    2015-01-01

    Occult hemorrhage in surgical/trauma intensive care unit (STICU) patients is common and may lead to circulatory collapse. Continuous electrocardiography (ECG) monitoring may allow for early identification and treatment, and could improve outcomes. We studied 4,259 consecutive admissions to the STICU at the University of Virginia Health System. We collected ECG waveform data captured by bedside monitors and calculated linear and non-linear measures of the RR interbeat intervals. We tested the hypothesis that a transfusion requirement of 3 or more PRBC transfusions in a 24 hour period is preceded by dynamical changes in these heart rate measures and performed logistic regression modeling. We identified 308 hemorrhage events. A multivariate model including heart rate, standard deviation of the RR intervals, detrended fluctuation analysis, and local dynamics density had a C-statistic of 0.62. Earlier detection of hemorrhage might improve outcomes by allowing earlier resuscitation in STICU patients.

  6. Blood Pressure vs. Heart Rate

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Blood Pressure vs. Heart Rate Updated:Aug 30,2016 Blood ... last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  7. The 24 Hours before Hospitalization: Factors Related to Suicide Attempting.

    ERIC Educational Resources Information Center

    Chiles, John A.; And Others

    1986-01-01

    Psychiatric inpatients (N=59) were interviewd concerning psychological and environmental events that occurred in the 24 hours prior to their hospitalization. Suicide attempters were more likely to have used alcohol or marijuana and less likely to have contacted a health care professional than suicide ideators, even when past history of suicide…

  8. Microtensile bond strength of resin-resin interfaces after 24-hour and 2-month soaking.

    PubMed

    Leavitt, Curry; Boberick, Kenneth G; Winkler, Sheldon

    2007-01-01

    Evaluate the bond strengths of denture base-repair materials to minimize recurrent failure rate. Use microtensile bond strength (muTBS) testing to evaluate the interfacial bonding strength of 6 commercial denture repair materials after 24-hour and 12-month soaking. Blocks of poly(methyl metacrylate) (PMMA) and Triad were fabricated, fractured, and repaired. Twenty bars (1 x 1 x 30 mm) per group were sectioned from each block parallel to the long axis and approximately 90 degrees to the resin-resin repair interface and stored before muTBS testing in a servo-hydraulic tensile-testing machine. Intact PMMA and Triad bars that had been soaked for 24 hours and 12 months were tested for reference. The 24-hour repair strengths for PMMA ranged from 52% to 84% of original strength. Soaking for 12 months resulted in a 20% decrease in strength for the PMMA control. The 12-month repair strengths for PMMA ranged from 43% to 74% of the 12-month soaked material strength. Triad repair tested 35% of original strength after soaking for 24 hours. Permabond (cyanoacrylate) to PMMA tested 47% of original strength after 24 hours of soaking and 26% of the 12-month soaked material strength. Permabond to Triad tested 30% of original strength after 24 hours of soaking. Permabond and Triad showed a 100% adhesive mode of failure. All other materials tested exhibited either an adhesive mode of failure at the denture base-repair-material interface or a complex cohesive failure within the repair-material interface. The muTBS approach can be used to analyze the resin-resin interface of repaired acrylics. The relatively small standard deviations make the muTBS approach attractive. In this study, muTBS was used to evaluate the repair strength of 6 denture repair materials enabling clinicians to make clinical judgments regarding the strongest repair bond available. PMID:17987865

  9. [Heart rate variability analysis: a new approach in clinical research methodology for neonatal sepsis].

    PubMed

    Cuestas, Eduardo; Rizzotti, Alina; Agüero, Guillermo

    2011-08-01

    The knowledge on neonatal sepsis has increase significantly, but a clinical or biochemical marker is not available for an early and appropriate diagnosis. This fact results of an inadequate analysis which might be missing important quantum of biological information. A new method of nonlinear analysis have been proposed to investigate time series of physiological data, particularly heart rate variability analysis, that apparently would detect abnormal changes which precedes clinical or biochemical signs of infection by as much as 12-24 hours.

  10. Effect of daily oral omeprazole on 24 hour intragastric acidity.

    PubMed Central

    Walt, R P; Gomes, M D; Wood, E C; Logan, L H; Pounder, R E

    1983-01-01

    Twenty four hour intragastric acidity was measured in nine patients with duodenal ulcer before and after one week of treatment with oral omeprazole 30 mg daily, a drug that inhibits gastric secretion by inhibition of parietal cell H+K+ adenosinetriphosphatase (ATPase). Omeprazole virtually eliminated intragastric acidity in all patients: the median 24 hour intragastric pH rose from 1.4 to 5.3 and the mean hourly hydrogen ion activity fell from 38.50 to 1.95 mmol(mEq)/1 (p less than 0.001). This inhibition of 24 hour intragastric acidity is more profound than that previously reported with either cimetidine 1 g daily or ranitidine 300 mg daily. PMID:6407676

  11. Dimensional analysis of heart rate variability in heart transplant recipients

    SciTech Connect

    Zbilut, J.P.; Mayer-Kress, G.; Geist, K.

    1987-01-01

    We discuss periodicities in the heart rate in normal and transplanted hearts. We then consider the possibility of dimensional analysis of these periodicities in transplanted hearts and problems associated with the record.

  12. [Gastroesophageal reflux during pregnancy: 24-hour esophageal ph monitoring].

    PubMed

    Anton, C; Anton, E; Drug, V; Stanciu, C

    2001-01-01

    Gastroesophageal reflux (GER) occurs in 30-50% of all pregnancies. The progressive rise in plasma progesterone has been suggested as a possible mediator of GER during pregnancy. Recent advances in technology have made it possible to detect GER through monitoring of esophageal pH for prolonged periods, including sleep. 24-hour pH monitoring is the proper method for diagnosing GER in pregnant women. If 24-hour esophageal pH monitoring is to be a useful diagnostic tool, it must reliably discriminate GER patients despite daily variations in distal esophageal acid exposure. To address this issue, we studied 62 women (30 healthy non-pregnant women without GER symptoms and 32 pregnant women with GER symptoms-heartburn, acid regurgitation) with 24-hour esophageal pH monitoring. Intrasubject reproducibility of three pH parameters to discriminate the presence of abnormal acid reflux was determined (DeMeester score, Kaye score, circadian one hour diagram for pH < 4). Each patient was interviewed, using a reliable questionnaire detailing individual habits, life style characteristics and symptoms, at four time points during the first, second, third trimesters of pregnancy and post-partum period. Symptoms of GER are common in pregnancy and although GER rarely endangers maternal or fetal health, it can significantly affect patient comfort and quality of life. We conclude: 1. GER is almost constantly present during pregnancy, increasing with gestational age. 2. The most important pH--parameter is DeMcester score. 3. Heartburn disappear after delivery. 4. 24-hour esophageal pH monitoring is the gold standard for measuring acid exposure and is a reproducible test for the diagnosis of GER in pregnancy.

  13. Enhanced carotid-cardiac baroreflex response and elimination of orthostatic hypotension 24 hours after acute exercise in paraplegics

    NASA Technical Reports Server (NTRS)

    Engelke, K. A.; Shea, J. D.; Doerr, D. F.; Convertino, V. A.

    1992-01-01

    To test the hypothesis that an acute bout of maximal exercise can ameliorate orthostatic hypotension consequent to prolonged wheelchair confinement, we evaluated heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure responses during 15 minutes of 70 degrees head-up tilt (HUT) in 10 paraplegic subjects 24 hours after arm crank exercise designed to elicit maximal effort, and during a control (no exercise) conditions. Additionally, the carotid baroreceptor stimulus-cardiac response relationship was determined by measurement of R-R interval during external application of graded pressures to the carotid sinuses. One week separated the treatment conditions. The maximum slope of the carotid-cardiac baroreflex response was increased (p = 0.049) by exercise (6.2 +/- 1.7 msec/mmHg) compared to control (3.3 +/- 0.6). During control HUT, HR increased from 61 +/- 1 to 90 +/- 7 bpm (p = 0.001) while SBP decreased from 118 +/- 5 to 106 +/- 9 mmHg (p = 0.025). During HUT 24 hours after exercise, HR increased from 60 +/- 2 to 90 +/- 4 bpm (p = 0.001), but the reduction in SBP was essentially eliminated (116 +/- 5 to 113 +/- 5 mmHg).

  14. Impact of age and basic heart rate on heart rate turbulence in healthy persons.

    PubMed

    Schwab, Jörg Otto; Eichner, Gerrit; Shlevkov, Nikolay; Schrickel, Jan; Yang, Alexander; Balta, Osman; Lewalter, Thorsten; Lüderitz, Berndt

    2005-01-01

    Postextrasystolic acceleration of heart rate (HR), known as HR turbulence (HRT) is attenuated in patients with coronary artery disease at increased risk of adverse events. The influence of age and basic HR on HRT have not been evaluated in a large cohort of persons. In 95 healthy individuals, HRT onset (TO) and slope (TS) were calculated from 24-hour ambulatory electrocardiograms, as well as the turbulence timing (TT). Gender specific differences in TO and TS were compared in simple, linear, weighted regression model. The influence of age and the basic HR preceding ventricular premature contractions on HRT were examined. We found that, in men and women, TO decreases as basic HR increases (P < 0.01). In contrast, in men, TS decreased as basic HR increases, whereas in women, basic HR influenced TS only slightly (P < 0.01). A multiple, linear regression model revealed a decrease in HRT with increasing age in men. In conclusion, physiological acceleration of the HR within the first 11 beats after premature ventricular complex (VPC) was observed in >75% of healthy individuals. An accelerating HR preceding the VPC influenced HRT in men. An increasing age was associated with a decrease in HRT in men and a decrease in TO in women. These results illustrate the importance of physiological modulations of HRT when used for risk stratification, especially in older populations.

  15. Laparoscopic Colon Resections With Discharge Less Than 24 Hours

    PubMed Central

    Ganji, Maedeh; Alam, Shaan E.; Kar, Pran M.

    2013-01-01

    Background and Objectives: A short hospital stay is one of the main advantages of laparoscopic surgery. Previous studies have shown that after a multimodal fast-track process, the hospital length of stay can be shortened to between 2 and 5 days. The objective of this review is to show that the hospital length of stay can, in some cases, be reduced to <24 hours. Methods: This study retrospectively reviews a surgeon's experience with laparoscopic surgery over a 12-month period. Seven patients were discharged home within 24 hours after minimally invasive laparoscopic surgical treatment, following a modified fast-track protocol that was adopted for perioperative care. Results: Of the 7 patients, 4 received laparoscopic right hemicolectomy for malignant disease and 3 underwent sigmoid colectomies for recurrent diverticulitis. The mean hospital stay was 21 hours, 47 minutes; the mean volume of intraoperative fluid (lactated Ringer) was 1850 mL; the mean surgical blood loss was only 74.3 mL; the mean duration of surgery was 118 minutes; and the patients were ambulated and fed a liquid diet after recovery from anesthesia. The reviewed patients had functional gastrointestinal tracts and were agreeable to the timing of discharge. On the follow-up visit, they showed no adverse consequences such as bleeding, infection, or anastomotic leak. Conclusion: Laparoscopic colon surgery that incorporated multimodal perioperative care allowed patients to be discharged within the first 24 hours. Careful postoperative outpatient follow-up is important in monitoring complications such as anastomotic leak, which may not present until postoperative day 5. PMID:23925012

  16. The relation of ambulatory heart rate with all-cause mortality among middle-aged men: a prospective cohort study.

    PubMed

    Korshøj, Mette; Lidegaard, Mark; Kittel, France; Van Herck, Koen; De Backer, Guy; De Bacquer, Dirk; Holtermann, Andreas; Clays, Els

    2015-01-01

    The aim of this study was to investigate the association between average 24-hour ambulatory heart rate and all-cause mortality, while adjusting for resting clinical heart rate, cardiorespiratory fitness, occupational and leisure time physical activity as well as classical risk factors. A group of 439 middle-aged male workers free of baseline coronary heart disease from the Belgian Physical Fitness Study was included in the analysis. Data were collected by questionnaires and clinical examinations from 1976 to 1978. All-cause mortality was collected from the national mortality registration with a mean follow-up period of 16.5 years, with a total of 48 events. After adjustment for all before mentioned confounders in a Cox proportional hazards regression analysis, a significant increased risk for all-cause mortality was found among the tertile of workers with highest average ambulatory heart rate compared to the tertile with lowest ambulatory heart rate (Hazard ratio = 3.21, 95% confidence interval: 1.22-8.44). No significant independent association was found between resting clinic heart rate and all-cause mortality. The study indicates that average 24-hour ambulatory heart rate is a strong predictor of all-cause mortality independent from resting clinic heart rate, cardiorespiratory fitness, occupational and leisure time physical activity and other classical risk factors among healthy middle-aged workers.

  17. Heart rate reduction in coronary artery disease and heart failure.

    PubMed

    Ferrari, Roberto; Fox, Kim

    2016-08-01

    Elevated heart rate is known to induce myocardial ischaemia in patients with coronary artery disease (CAD), and heart rate reduction is a recognized strategy to prevent ischaemic episodes. In addition, clinical evidence shows that slowing the heart rate reduces the symptoms of angina by improving microcirculation and coronary flow. Elevated heart rate is an established risk factor for cardiovascular events in patients with CAD and in those with chronic heart failure (HF). Accordingly, reducing heart rate improves prognosis in patients with HF, as demonstrated in SHIFT. By contrast, data from SIGNIFY indicate that heart rate is not a modifiable risk factor in patients with CAD who do not also have HF. Heart rate is also an important determinant of cardiac arrhythmias; low heart rate can be associated with atrial fibrillation, and high heart rate after exercise can be associated with sudden cardiac death. In this Review, we critically assess these clinical findings, and propose hypotheses for the variable effect of heart rate reduction in cardiovascular disease.

  18. Multifractality and heart rate variability

    NASA Astrophysics Data System (ADS)

    Sassi, Roberto; Signorini, Maria Gabriella; Cerutti, Sergio

    2009-06-01

    In this paper, we participate to the discussion set forth by the editor of Chaos for the controversy, "Is the normal heart rate chaotic?" Our objective was to debate the question, "Is there some more appropriate term to characterize the heart rate variability (HRV) fluctuations?" We focused on the ≈24 h RR series prepared for this topic and tried to verify with two different techniques, generalized structure functions and wavelet transform modulus maxima, if they might be described as being multifractal. For normal and congestive heart failure subjects, the hq exponents showed to be decreasing for increasing q with both methods, as it should be for multifractal signals. We then built 40 surrogate series to further verify such hypothesis. For most of the series (≈75%-80% of cases) multifractality stood the test of the surrogate data employed. On the other hand, series coming from patients in atrial fibrillation showed a small, if any, degree of multifractality. The population analyzed is too small for definite conclusions, but the study supports the use of multifractal series to model HRV. Also it suggests that the regulatory action of autonomous nervous system might play a role in the observed multifractality.

  19. Wearable sensor for heart rate detection

    NASA Astrophysics Data System (ADS)

    Shi, Cong; Liu, Xiaohua; Kong, Lingqin; Wu, Jizhe; Liu, Ming; Dong, Liquan; Hui, Mei; Zhao, Yuejin

    2015-08-01

    In recent years heart and blood vessel diseases kill more people than everything else combined. The daily test of heart rate for the prevention and treatment of the heart head blood-vessel disease has the vital significance. In order to adapt the transformation of medical model and solve the low accuracy problem of the traditional method of heart rate measuring, we present a new method to monitor heart rate in this paper. The heart rate detection is designed for daily heart rate detection .The heart rate signal is collected by the heart rate sensor. The signal through signal processing circuits converts into sine wave and square wave in turn. And then the signal is transmitted to the computer by data collection card. Finally, we use LABVIEW and MATLAB to show the heart rate wave and calculate the heart rate. By doing contrast experiment with medical heart rate product, experimental results show that the system can realize rapidly and accurately measure the heart rate value. A measurement can be completed within 10 seconds and the error is less than 3beat/min. And the result shows that the method in this paper has a strong anti-interference ability. It can effectively suppress the movement interference. Beyond that the result is insensitive to light.

  20. [Resting heart rate and cardiovascular disease].

    PubMed

    Brito Díaz, Buenaventura; Alemán Sánchez, José Juan; Cabrera de León, Antonio

    2014-07-01

    Heart rate reflects autonomic nervous system activity. Numerous studies have demonstrated that an increased heart rate at rest is associated with cardiovascular morbidity and mortality as an independent risk factor. It has been shown a link between cardiac autonomic balance and inflammation. Thus, an elevated heart rate produces a micro-inflammatory response and is involved in the pathogenesis of endothelial dysfunction. In turn, decrease in heart rate produces benefits in congestive heart failure, myocardial infarction, atrial fibrillation, obesity, hyperinsulinemia, insulin resistance, and atherosclerosis. Alteration of other heart rate-related parameters, such as their variability and recovery after exercise, is associated with risk of cardiovascular events. Drugs reducing the heart rate (beta-blockers, calcium antagonists and inhibitors of If channels) have the potential to reduce cardiovascular events. Although not recommended in healthy subjects, interventions for reducing heart rate constitute a reasonable therapeutic goal in certain pathologies.

  1. How to Take Your Heart Rate

    MedlinePlus

    ... Page 1 of 2 The chart illustrates target heart rate ranges for exercise based on the maximal heart rate for selected ... to the next older age listed. - Compare your heart rate to the target exercise range. • If you are doing moderate exercise, your ...

  2. Increased heteroscedasticity of heart rate in fatal heart failure

    NASA Astrophysics Data System (ADS)

    Struzik, Z. R.; Kiyono, K.; Hayano, J.; Watanabe, E.; Yamamoto, Y.

    2008-04-01

    Healthy human heart rate is known to fluctuate in a highly complex manner, displaying complexity characteristics such as those shared by physical systems at a critical state. It is, however, widely believed that chronic heart failure reduces this complexity and that heart rate data from chronic-heart-failure patients can be used for the validation of complexity measures and paradigms applicable both to heart rate and more generally to assess any system's complexity. Here, we counter the above belief, showing an increase in fluctuations and in complexity of heart rate in chronic-heart-failure patients, in particular those at risk of death. This is supported by evidence of increased non-Gaussianity and heteroscedasticity resulting from the emergence of a characteristic correlation scale in the magnitude correlation landscape.

  3. Attenuated sympathetic nerve responses after 24 hours of bed rest

    NASA Technical Reports Server (NTRS)

    Khan, Mazhar H.; Kunselman, Allen R.; Leuenberger, Urs A.; Davidson, William R Jr; Ray, Chester A.; Gray, Kristen S.; Hogeman, Cynthia S.; Sinoway, Lawrence I.

    2002-01-01

    Bed rest reduces orthostatic tolerance. Despite decades of study, the cause of this phenomenon remains unclear. In this report we examined hemodynamic and sympathetic nerve responses to graded lower body negative pressure (LBNP) before and after 24 h of bed rest. LBNP allows for baroreceptor disengagement in a graded fashion. We measured heart rate (HR), cardiac output (HR x stroke volume obtained by echo Doppler), and muscle sympathetic nerve activity (MSNA) during a progressive and graded LBNP paradigm. Negative pressure was increased by 10 mmHg every 3 min until presyncope or completion of -60 mmHg. After bed rest, LBNP tolerance was reduced in 11 of 13 subjects (P <.023), HR was greater (P <.002), cardiac output was unchanged, and the ability to augment MSNA at high levels of LBNP was reduced (rate of rise for 30- to 60-mmHg LBNP before bed rest 0.073 bursts x min(-1) x mmHg(-1); after bed rest 0.035 bursts x min(-1) x mmHg(-1); P < 0.016). These findings suggest that 24 h of bed rest reduces sympathetic nerve responses to LBNP.

  4. Managing sleep and wakefulness in a 24-hour world

    PubMed Central

    Coveney, Catherine M

    2014-01-01

    This article contributes to literature on the sociology of sleep by exploring the sleeping practices and subjective sleep experiences of two social groups: shift workers and students. It draws on data, collected in the UK from 25 semi-structured interviews, to discuss the complex ways in which working patterns and social activities impact upon experiences and expectations of sleep in our wired awake world. The data show that, typically, sleep is valued and considered to be important for health, general wellbeing, appearance and physical and cognitive functioning. However, sleep time is often cut back on in favour of work demands and social activities. While shift workers described their efforts to fit in an adequate amount of sleep per 24-hour period, for students, the adoption of a flexible sleep routine was thought to be favourable for maintaining a work–social life balance. Collectively, respondents reported using a wide range of strategies, techniques, technologies and practices to encourage, overcome or delay sleep(iness) and boost, promote or enhance wakefulness/alertness at socially desirable times. The analysis demonstrates how social context impacts not only on how we come to think about sleep and understand it, but also how we manage or self-regulate our sleeping patterns. PMID:23957268

  5. Cognitive Performance during a 24-Hour Cold Exposure Survival Simulation.

    PubMed

    Taber, Michael J; Hartley, Geoffrey L; McGarr, Gregory W; Zaharieva, Dessi; Basset, Fabien A; Hynes, Zach; Haman, Francois; Pinet, Bernard M; DuCharme, Michel B; Cheung, Stephen S

    2016-01-01

    Survivor of a ship ground in polar regions may have to wait more than five days before being rescued. Therefore, the purpose of this study was to explore cognitive performance during prolonged cold exposure. Core temperature (T c) and cognitive test battery (CTB) performance data were collected from eight participants during 24 hours of cold exposure (7.5°C ambient air temperature). Participants (recruited from those who have regular occupational exposure to cold) were instructed that they could freely engage in minimal exercise that was perceived to maintaining a tolerable level of thermal comfort. Despite the active engagement, test conditions were sufficient to significantly decrease T c after exposure and to eliminate the typical 0.5-1.0°C circadian rise and drop in core temperature throughout a 24 h cycle. Results showed minimal changes in CTB performance regardless of exposure time. Based on the results, it is recommended that survivors who are waiting for rescue should be encouraged to engage in mild physical activity, which could have the benefit of maintaining metabolic heat production, improve motivation, and act as a distractor from cold discomfort. This recommendation should be taken into consideration during future research and when considering guidelines for mandatory survival equipment regarding cognitive performance. PMID:27478839

  6. Cognitive Performance during a 24-Hour Cold Exposure Survival Simulation

    PubMed Central

    Hartley, Geoffrey L.; Zaharieva, Dessi; Basset, Fabien A.; Hynes, Zach

    2016-01-01

    Survivor of a ship ground in polar regions may have to wait more than five days before being rescued. Therefore, the purpose of this study was to explore cognitive performance during prolonged cold exposure. Core temperature (Tc) and cognitive test battery (CTB) performance data were collected from eight participants during 24 hours of cold exposure (7.5°C ambient air temperature). Participants (recruited from those who have regular occupational exposure to cold) were instructed that they could freely engage in minimal exercise that was perceived to maintaining a tolerable level of thermal comfort. Despite the active engagement, test conditions were sufficient to significantly decrease Tc after exposure and to eliminate the typical 0.5–1.0°C circadian rise and drop in core temperature throughout a 24 h cycle. Results showed minimal changes in CTB performance regardless of exposure time. Based on the results, it is recommended that survivors who are waiting for rescue should be encouraged to engage in mild physical activity, which could have the benefit of maintaining metabolic heat production, improve motivation, and act as a distractor from cold discomfort. This recommendation should be taken into consideration during future research and when considering guidelines for mandatory survival equipment regarding cognitive performance. PMID:27478839

  7. [Necessity of a 24-hour system of blood transfusion testing].

    PubMed

    Kishimoto, Yuji

    2003-01-01

    The preventive effects of a 24-hour system of blood transfusion testing on mistyping of transfused blood was examined. Blood transfusion tests have been performed by blood transfusion technologists during working hours and by physicians at other times. In March 2000, we introduced a system in which technologists perform blood transfusion tests after working hours. Technologists of the Blood Transfusion Unit and Central Clinical Laboratory perform the test jointly, and column agglutination technology was introduced as the test method. A computer system setup exclusively for the testing was also introduced to perform computer cross-matching. Since transfusion error is likely to occur during emergency blood transfusion, a manual was established to prioritize safety. After introduction of the system, mistyping that may have been caused by inaccurate blood test results markedly decreased, confirming the usefulness of this system for prevention of mistyping. In addition, transfusion errors also decreased in wards and the improved system increased the safety of the entire medical care system. The frequency of mistyping was about 1% when physicians performed blood typing, showing the importance of clinical technologists for blood transfusion tests. PMID:12652691

  8. Managing sleep and wakefulness in a 24-hour world.

    PubMed

    Coveney, Catherine M

    2014-01-01

    This article contributes to literature on the sociology of sleep by exploring the sleeping practices and subjective sleep experiences of two social groups: shift workers and students. It draws on data, collected in the UK from 25 semi-structured interviews, to discuss the complex ways in which working patterns and social activities impact upon experiences and expectations of sleep in our wired awake world. The data show that, typically, sleep is valued and considered to be important for health, general wellbeing, appearance and physical and cognitive functioning. However, sleep time is often cut back on in favour of work demands and social activities. While shift workers described their efforts to fit in an adequate amount of sleep per 24-hour period, for students, the adoption of a flexible sleep routine was thought to be favourable for maintaining a work-social life balance. Collectively, respondents reported using a wide range of strategies, techniques, technologies and practices to encourage, overcome or delay sleep(iness) and boost, promote or enhance wakefulness/alertness at socially desirable times. The analysis demonstrates how social context impacts not only on how we come to think about sleep and understand it, but also how we manage or self-regulate our sleeping patterns.

  9. CAFFEINE IMPROVES HEART RATE WITHOUT IMPROVING SEPSIS SURVIVAL

    PubMed Central

    Bauzá, Gustavo; Remick, Daniel

    2015-01-01

    Introduction Caffeine is consumed on a daily basis for its nervous system stimulant properties and is a global adenosine receptor antagonist. Since adenosine receptors have been found to play a major role in regulating the immune response to a septic insult, we investigated if caffeine consumption prior to a septic insult would alter immunological and physiological responses, as well as survival. Methods Two separate experimental designs were employed, both using outbred female ICR mice. In the first experiment mice were administered 20mg/kg of caffeine (equal to 2–3 cups of coffee for a human) or normal saline intraperitoneally at the time of cecal ligation and puncture (CLP). Immunological parameters including cytokines and local cell recruitment measured. In the second experiment caffeine (10mg/kg/hr) was delivered continuously for 24 hours via a subcutaneous infusion pump placed the day prior to CLP and hemodynamic parameters were examined. In both experiments survival was followed for five days. Results A single dose of caffeine at the initiation of sepsis did not alter survival. This single dose of caffeine did significantly increase in plasma levels of the chemokine KC six hours after the onset of sepsis compared to septic mice given normal saline. There were no changes in IL-6 or IL-10 levels in the caffeine groups. Peritoneal lavages performed 24 hours post-CLP showed no difference in the levels of IL-6, TNF, KC, MIP-1, IL-10 or the IL-1 receptor antagonist between caffeine and normal saline treated mice. Additionally, the lavages yielded similar numbers of cells (4.1×106 vehicle vs. 6.9×106 caffeine) and bacterial colony forming units (CFU, 4.1 million CFU vehicle vs. 2.8 million CFU caffeine). In the infusion group, caffeine also did not alter survival. However, caffeine infusion did increase heart rate prior to CLP, and prevented the decline in heart rate after CLP. Conclusion Caffeine increased heart rate in mice but does not impact cytokine

  10. Autonomic functions in acrocyanosis assessed by heart rate variability

    PubMed Central

    Yılmaz, Sedat; Yokuşoğlu, Mehmet; Çınar, Muhammet; Şimşek, İsmail; Baysan, Oben; Öz, Bilgehan Savaş; Erdem, Hakan; Pay, Salih; Dinç, Ayhan

    2014-01-01

    Objective To evaluate the autonomic activity of patients with acrocyanosis by using heart rate variability indices. Material and Methods The study group consisted of 24 patients with acrocyanosis and the control group contained 22 sex- and age-matched healthy subjects. All subjects underwent 24-hour Holter monitoring. Among the heart rate variability (HRV) parameters, time-domain and frequency-domain indices were analysed. Results The time-domain indices of HRV indicating global autonomic functions were found to be increased, and indices indicating parasympathetic activity showed a significant decrease in the patient group. Power-spectral analysis of HRV revealed that the low frequency and high frequency power were higher in the patient group than in controls. However, the ratio of Low Frequency/High Frequency was found to be lower in the patient group than in controls. Conclusion In acrocyanosis, both sympathetic and parasympathetic systems seem to be disrupted. Therefore, we may conclude that acrocyanosis may be resulted of systemic autonomic imbalance rather than pure sympathetic over-activation. Also, these results suggest that acrocyanosis is not a localised disorder; on the contrary, it is associated with various abnormalities of the systemic autonomic nervous system.

  11. Heart rate variability in idiopathic dilated cardiomyopathy: relation to disease severity and prognosis.

    PubMed Central

    Yi, G.; Goldman, J. H.; Keeling, P. J.; Reardon, M.; McKenna, W. J.; Malik, M.

    1997-01-01

    OBJECTIVE: To assess the clinical importance of heart rate variability (HRV) in patients with idiopathic dilated cardiomyopathy (DCM). PATIENTS AND METHODS: Time domain analysis of 24 hour HRV was performed in 64 patients with DCM, 19 of their relatives with left ventricular enlargement (possible early DCM), and 33 healthy control subjects. RESULTS: Measures of HRV were reduced in patients with DCM compared with controls (P < 0.05). HRV parameters were similar in relatives and controls. Measures of HRV were lower in DCM patients in whom progressive heart failure developed (n = 28) than in those who remained clinically stable (n = 36) during a follow up of 24 (20) months (P = 0.0001). Reduced HRV was associated with NYHA functional class, left ventricular end diastolic dimension, reduced left ventricular ejection fraction, and peak exercise oxygen consumption (P < 0.05) in all patients. DCM patients with standard deviation of normal to normal RR intervals calculated over the 24 hour period (SDNN) < 50 ms had a significantly lower survival rate free of progressive heart failure than those with SDNN > 50 ms (P = 0.0002, at 12 months; P = 0.0001, during overall follow up). Stepwise multiple regression analysis showed that SDNN < 50 ms identified, independently of other clinical variables, patients who were at increased risk of developing progressive heart failure (P = 0.0004). CONCLUSIONS: HRV is reduced in patients with DCM and related to disease severity. HRV is clinically useful as an early non-invasive marker of DCM deterioration. PMID:9068391

  12. Transcontinental and translational high-tech acupuncture research using computer-based heart rate and "Fire of Life" heart rate variability analysis.

    PubMed

    Litscher, Gerhard

    2010-09-01

    A variable heartbeat was considered a sign of good health by ancient Asian physicians. Today, new computer-based methods (e.g., "Fire of Life" analysis) allow quantification of heart rate and heart rate variability during acupuncture. The objective of this article is to compare different acupuncture methods to evaluate the influence of acupuncture on heart rhythm in short-term and long-term measurements. There were four main sections in this study: (A) a randomized controlled study using needle acupuncture and acupressure at Yintang (Ex1); (B) an innovative blue (violet) laser acupuncture randomized controlled study in Asian volunteers; (C) a comparative study using moxibustion methods; and (D) teleacupuncture. A total of 72 patients (mean age ± SD: 27.9 ± 8.6 years) were monitored over periods of 20 minutes to 24 hours in Asia and Austria. Acupuncture was performed with metal needles (in sections A, C and D) or blue laser (in section B) on Yintang, Neiguan, Guanyuan or a special acupuncture regimen for stress disorders (in sections A, B, C and D, respectively). Significant decreases in heart rate after verum intervention at Yintang, Neiguan and Guanyuan were found. Improvements in state of health following teleacupuncture were also noted. Computer-based heart rate and heart rate variability analysis was demonstrated to be effective in evaluating the status of health during acupuncture.

  13. Comparison of Population Iodine Estimates from 24-Hour Urine and Timed-Spot Urine Samples

    PubMed Central

    Cogswell, Mary E.; Swanson, Christine A.; Sullivan, Kevin M.; Chen, Te-Ching; Carriquiry, Alicia L.; Dodd, Kevin W.; Caldwell, Kathleen L.; Wang, Chia-Yih

    2014-01-01

    Background: Median urine iodine concentration (UIC; μg/L) in spot urine samples is recommended for monitoring population iodine status. Other common measures are iodine:creatinine ratio (I/Cr; μg/g) and estimated 24-hour urine iodine excretion (UIE; I/Cr×predicted 24-hour Cr; μg/day). Despite different units, these measures are often used interchangeably, and it is unclear how they compare with the reference standard 24-hour UIE. Methods: Volunteers aged 18–39 years collected all their urine samples for 24 hours (n=400). Voids from morning, afternoon, evening, overnight, and a composite 24-hour sample were analyzed for iodine. We calculated median observed 24-hour UIE and 24-hour UIC, and spot UIC, I/Cr, and two measures of estimated UIE calculated using predicted 24-hour Cr from published estimates by Kesteloot and Joosens (varies by age and sex) and published equations by Mage et al. (varies by age, sex, race, and anthropometric measures). We examined mean differences and relative difference across iodine excretion levels using Bland–Altman plots. Results: Median 24-hour UIE was 173.6 μg/day and 24-hour UIC was 144.8 μg/L. From timed-spot urine samples, estimates were: UIC 147.3–156.2 μg/L; I/Cr 103.6–114.3 μg/g, estimated 24-hour UIE (Kesteloot and Joosens) 145.7–163.3 μg/day; and estimated 24-hour UIE (Mage) 176.5–187.7 μg/day. Iodine measures did not vary consistently by timing of spot urine collection. Compared with observed 24-hour UIE, on average, estimated (Mage) 24-hour UIE was not significantly different, while estimated 24-hour UIE (Kesteloot and Joosens) was significantly different for some ethnicity/sex groups. Compared with 24-hour UIC, on average, spot UIC did not differ. Conclusions: Estimates of UIC, I/Cr, and estimated 24-hour UIE (I/Cr×predicted 24-hour Cr) from spot urine samples should not be used interchangeably. Estimated 24-hour UIE, where predicted 24-hour Cr varies by age, sex, ethnicity, and

  14. Preparation and results of a 24-hour orbital flight.

    PubMed

    Titov, G S

    1963-01-01

    The space age presents man with unprecedented opportunities for discovery and for cooperative endeavors to benefit all mankind. My flight of August 6-7, 1961 was conducted for the purpose of determining whether man can stay and work effectively and whether all systems of the spaceship can operate successfully during a period of 24 hours in space. The flight of Vostok II represents an experimental step in a logical sequence which included the first earth orbiting flight of USSR citizen Yuri A. Gagarin. Preparation for the flight included the study of theoretical and applied subjects, testing in various kinds of apparatus which provide acceleration, heat and isolation experience, brief airborne weightless flights and parachute landings, in addition to extensive training in a real spacecraft having simulators for normal and emergency contingencies of space flight. The actual flight was therefore carried out with a sense of confidence and familiarity and with continuous close radio contact with ground centers from whom my fellow cosmonauts served as spokesmen. Sequential boosters totaling 600 000 kg thrust placed the 4731 kg spaceship into a perfect orbit varying in altitude from 178-246 km in a plane 64 degrees 58' inclined to the equator. The spaceship made 17 orbits around the earth landing 25 hours, 18 minutes after take-off. The cabin had full atmospheric pressure and a comfortable habitability which could be extended for 10 days. I was able to maneuver the spaceship and perform many other control functions, make observations and take pictures of the earth and its cloud cover, eat meals and sleep all with good efficiency. I experienced mild symptoms suggestive of seasickness which were aggravated by head turning, ameliorated by sleep and entirely relieved by resumption of g-loading during descent. Altogether analyses of the physical and structural performance of the spaceship and the continuously monitored physiological responses of the pilot indicate that all

  15. Flexibility of working hours in the 24-hour society.

    PubMed

    Costa, G

    2006-01-01

    The 24-hour Society undergoes an ineluctable process towards a social organisation where time constraints are no more restricting human life. The borders between working and social times are no more fixed and rigidly determined, and the value of working time changes according to the different economic and social effects you may consider. Shift and night work, irregular and flexible working hours, together with new technologies, are the milestone of this epochal passage. What are the advantages and disadvantages for the individual, the companies, and the society? What is the cost/benefit ratio in terms of health and social well-being? Coping properly with this process means avoiding a passive acceptance of it with consequent maladjustments at both individual and social level, but adopting effective preventive and compensative strategies aimed at building up a more sustainable society. Flexible working times now appear to be one of the best ways to cope with the demands of the modern life, but there are different points of view about labour and temporal 'flexibility" between employers and employees. For the former it means a prompt adaptation to market demands and technological innovations; for the latter it is a way to improve working and social life, by decreasing work constraints and increasing control and autonomy. Although it can be easily speculated that individual-based 'flexibility" should improve health and well-being, and especially satisfaction, whereas company-based flexibility" might interfere negatively, the effective consequences on health and well-being have still to be analysed properly. PMID:17017360

  16. 24 hour blood pressure monitoring in healthy and hypertensive children.

    PubMed Central

    Reusz, G S; Hóbor, M; Tulassay, T; Sallay, P; Miltényi, M

    1994-01-01

    24 Hour ambulatory blood pressure monitoring (ABPM) was performed to provide data on the normal daily blood pressure of healthy schoolchildren and on patients with hypertension. The subjects studied were 123 healthy schoolchildren with a mean (SD) age of 12.5 (1.6) years (range 9.5-14.5 years), 24 children with borderline or mild hypertension, 17 with renal hypertension and normal renal function, 10 with chronic renal failure, and six with a renal allograft. In eight children with definite renal disease a second measurement was performed after treatment modification. The monitor used for ABPM was validated with a mercury column manometer. The mean (SD) of the signed differences of the blood pressure measured by the two methods was -0.19 (1.75) mmHg for the systolic and -0.21 (2.11) mmHg for the diastolic blood pressure (n = 60). Normal values for daytime and night time blood pressure were determined for those aged 10-14 years. The mean (SD) blood pressure of the 123 children was 109 (7)/66 (8) mmHg (systolic/diastolic) for the daytime and 96 (8)/52 (7) mmHg at night time. Of the 24 children with borderline or mild hypertension 14 had a raised blood pressure on ABPM. The circadian rhythm was disturbed in three children of this group. Even children with normal daytime blood pressure had significantly higher systolic blood pressure in the night when compared with the controls. The incidence of disturbed circadian rhythm was higher in the groups with renal hypertension (4/17 in the subgroup with normal renal function, 5/16 in the group with renal failure and/or transplantation). All children undergoing a second ABPM measurement had a lower average blood pressure after treatment adjustment. ABPM measurements were reproducible and accurate. The method provided new data on the physiological circadian variation of blood pressure in healthy children. It proved to be a helpful tool in the diagnosis of hypertension, particularly in the detection of cases of disturbance of the

  17. [Heart rate variability analysis: a new approach in clinical research methodology for neonatal sepsis].

    PubMed

    Cuestas, Eduardo; Rizzotti, Alina; Agüero, Guillermo

    2011-08-01

    The knowledge on neonatal sepsis has increase significantly, but a clinical or biochemical marker is not available for an early and appropriate diagnosis. This fact results of an inadequate analysis which might be missing important quantum of biological information. A new method of nonlinear analysis have been proposed to investigate time series of physiological data, particularly heart rate variability analysis, that apparently would detect abnormal changes which precedes clinical or biochemical signs of infection by as much as 12-24 hours. PMID:21829875

  18. Evaluation of Intradermal and Subcutaneous Infusion Set Performance Under 24-Hour Basal and Bolus Conditions

    PubMed Central

    McVey, Elaine; Keith, Steven; Herr, Joshua K.; Sutter, Diane; Pettis, Ronald J.

    2015-01-01

    Background: This study sought to assess the function and delivery reliability of intradermal (ID) infusion sets used with commercial insulin pumps. Method: Healthy subjects (n = 43) were randomized to either ID or subcutaneous (SC) arms, and received basal/bolus placebo delivery for 24 hours. Subjects received 4 of 8 infusion set combinations (ID: microneedle design A or B, with 2 pump brands [Animas or MiniMed]; SC: Teflon Quickset or steel Rapid-D, Animas pump only, with or without overtaping) and were evaluated for pump occlusion alarms, fluid leakage, pain, and tissue tolerability. A novel algorithm was developed to determine flow consistency based on fluid pressure, and the duration and occurrence rate for periods of unalarmed but interrupted flow (“silent occlusions’”) were compared. Results: ID delivery was successfully maintained over the 24-hour infusion period. The number of silent occlusions was lower for ID microneedle cannula design B than A (P < .01) and lower for Rapid-D SC device compared to Quick-set (P = .03). There was no significant difference in the number of occlusion alarms between the ID and SC devices with the Animas pump. However, the pumps tested with ID devices had significantly different alarm rates (MiniMed 29.5%, Animas 0%, P < .001). Leakage and tissue tolerability were comparable across devices. Conclusion: The ID infusion set reliably delivered diluent for an extended 24-hour period in healthy subjects and was well tolerated. Silent occlusion flow interruptions could be detected in both ID and SC infusion sets using a proprietary algorithm. This algorithm is a promising method for quantitatively evaluating infusion set flow performance. PMID:26319228

  19. Heart rate reduction and longevity in mice.

    PubMed

    Gent, Sabine; Kleinbongard, Petra; Dammann, Philip; Neuhäuser, Markus; Heusch, Gerd

    2015-03-01

    Heart rate correlates inversely with life span across all species, including humans. In patients with cardiovascular disease, higher heart rate is associated with increased mortality, and such patients benefit from pharmacological heart rate reduction. However, cause-and-effect relationships between heart rate and longevity, notably in healthy individuals, are not established. We therefore prospectively studied the effects of a life-long pharmacological heart rate reduction on longevity in mice. We hypothesized, that the total number of cardiac cycles is constant, and that a 15% heart rate reduction might translate into a 15% increase in life span. C57BL6/J mice received either placebo or ivabradine at a dose of 50 mg/kg/day in drinking water from 12 weeks to death. Heart rate and body weight were monitored. Autopsy was performed on all non-autolytic cadavers, and parenchymal organs were evaluated macroscopically. Ivabradine reduced heart rate by 14% (median, interquartile range 12-15%) throughout life, and median life span was increased by 6.2% (p = 0.01). Body weight and macroscopic findings were not different between placebo and ivabradine. Life span was not increased to the same extent as heart rate was reduced, but nevertheless significantly prolonged by 6.2%.

  20. Prognostic significance of heart rate turbulence parameters in patients with chronic heart failure

    PubMed Central

    2014-01-01

    Background This study is aimed to evaluate the clinical significance of heart rate turbulence (HRT) parameters in predicting the prognosis in patients with chronic heart failure (CHF). Methods From June 2011 to December 2012, a total of 104 CHF patients and 30 healthy controls were enrolled in this study. We obtained a 24-hour Holter ECG recording to assess the HRT parameters, included turbulence onset (TO), turbulence slope (TS), standard deviation of N-N intervals (SDNN), and resting heart rate (RHR). The relationships between HRT parameters and the prognosis of CHF patients were determined. Results The assessment follow-up period lasted until January 31, 2013. The overall mortality of CHF patients was 9.6% (10/104). Our results revealed that CHF patients had higher levels of TO than those of healthy subjects, but the TS levels of CHF patients were lower than that of the control group. CHF patients with NYHA grade IV had higher HRT1/2 rate than those with NYHA grade II/III. There were statistical differences in TS, LVEF, SDNN and RHR between the non-deteriorating group and the non-survivor group. Significant differences in TS among the three groups were also found. Furthermore, CHF patients in the non-survivor group had lower levels of TS than those in the deteriorating group. Correlation analyses indicated that TO negatively correlate with SDNN, while TS positively correlated with SDNN and left ventricular ejection fraction (LVEF). We also observed negative correlations between TS and left ventricular end-diastolic cavity dimension (LVEDD), RHR, homocysteine (Hcy) and C-reactive protein (CRP). Multivariate Cox regression analysis further confirmed that LVEF (≤30%), HRT2, SDNN and RHR were independent risk factors which can indicate poor prognosis in CHF patients. Conclusions Our findings indicate that HRT may have good clinical predictive value in patients with CHF. Thus, quantifying HRT parameters could be a useful tool for predicting mortality in CHF

  1. Heart rate and respiratory rhythm dynamics on ascent to high altitude

    NASA Technical Reports Server (NTRS)

    Lipsitz, L. A.; Hashimoto, F.; Lubowsky, L. P.; Mietus, J.; Moody, G. B.; Appenzeller, O.; Goldberger, A. L.

    1995-01-01

    OBJECTIVE--To investigate the alterations in autonomic control of heart rate at high altitude and to test the hypothesis that hypoxaemic stress during exposure to high altitude induces non-linear, periodic heart rate oscillations, similar to those seen in heart failure and the sleep apnoea syndrome. SUBJECTS--11 healthy subjects aged 24-64. MAIN OUTCOME MEASURES--24 hour ambulatory electrocardiogram records obtained at baseline (1524 m) and at 4700 m. Simultaneous heart rate and respiratory dynamics during 2.5 hours of sleep by fast Fourier transform analysis of beat to beat heart rate and of an electrocardiographically derived respiration signal. RESULTS--All subjects had resting hypoxaemia at high altitude, with an average oxyhaemoglobin saturation of 81% (5%). There was no significant change in mean heart rate, but low frequency (0.01-0.05 Hz) spectral power was increased (P < 0.01) at high altitude. Time series analysis showed a complex range of non-linear sinus rhythm dynamics. Striking low frequency (0.04-0.06 Hz) heart rate oscillations were observed during sleep in eight subjects at high altitude. Analysis of the electrocardiographically derived respiration signal indicated that these heart rate oscillations correlated with low frequency respiratory oscillations. CONCLUSIONS--These data suggest (a) that increased low frequency power during high altitude exposure is not simply attributable to increased sympathetic modulation of heart rate, but relates to distinctive cardiopulmonary oscillations at approximately 0.05 Hz and (b) that the emergence of periodic heart rate oscillations at high altitude is consistent with an unstable cardiopulmonary control system that may develop on acute exposure to hypoxaemic stress.

  2. Heart-Rate and Breath-Rate Monitor

    NASA Technical Reports Server (NTRS)

    Cooper, T. G.

    1983-01-01

    Circuit requiring only four integrated circuits (IC's) measures both heart rate and breath rate. Phase-locked loops lock on heart-rate and respiration-rate input signals. Each loop IC contains two phase comparators. Positive-edge-triggered circuit used in making monitors insensitive to dutycycle variations.

  3. The Application of a Contact Lens Sensor in Detecting 24-Hour Intraocular Pressure-Related Patterns

    PubMed Central

    2016-01-01

    Glaucoma is one of the leading causes of blindness worldwide. Recent studies suggest that intraocular pressure (IOP) fluctuations, peaks, and rhythm are important factors in disease advancement. Yet, current glaucoma management remains hinged on single IOP measurements during clinic hours. To overcome this limitation, 24-hour IOP monitoring devices have been employed and include self-tonometry, permanent IOP, and temporary IOP monitoring. This review discusses each IOP measuring strategy and focuses on the recently FDA-approved contact lens sensor (CLS). The CLS records IOP-related ocular patterns for 24 hours continuously. Using the CLS, IOP-related parameters have been found to be associated with the rate of visual field progression in primary open-angle glaucoma, disease progression in primary angle-closure glaucoma, and various clinical variables in ocular hypertension. The CLS has been used to quantify blink rate and limbal strain and measure the circadian rhythm in a variety of disease states including normal-tension glaucoma and thyroid eye disease. The effects of various IOP-lowering interventions were also characterized using the CLS. CLS provides a unique, safe, and well-tolerated way to study IOP-related patterns in a wide range of disease states. IOP-related patterns may help identify patients most at risk for disease progression and assist with the development of tailored treatments. PMID:27525110

  4. The Application of a Contact Lens Sensor in Detecting 24-Hour Intraocular Pressure-Related Patterns.

    PubMed

    Xu, Sarah C; Gauthier, Angela C; Liu, Ji

    2016-01-01

    Glaucoma is one of the leading causes of blindness worldwide. Recent studies suggest that intraocular pressure (IOP) fluctuations, peaks, and rhythm are important factors in disease advancement. Yet, current glaucoma management remains hinged on single IOP measurements during clinic hours. To overcome this limitation, 24-hour IOP monitoring devices have been employed and include self-tonometry, permanent IOP, and temporary IOP monitoring. This review discusses each IOP measuring strategy and focuses on the recently FDA-approved contact lens sensor (CLS). The CLS records IOP-related ocular patterns for 24 hours continuously. Using the CLS, IOP-related parameters have been found to be associated with the rate of visual field progression in primary open-angle glaucoma, disease progression in primary angle-closure glaucoma, and various clinical variables in ocular hypertension. The CLS has been used to quantify blink rate and limbal strain and measure the circadian rhythm in a variety of disease states including normal-tension glaucoma and thyroid eye disease. The effects of various IOP-lowering interventions were also characterized using the CLS. CLS provides a unique, safe, and well-tolerated way to study IOP-related patterns in a wide range of disease states. IOP-related patterns may help identify patients most at risk for disease progression and assist with the development of tailored treatments. PMID:27525110

  5. Heart Rate and Reinforcement Sensitivity in ADHD

    ERIC Educational Resources Information Center

    Luman, Marjolein; Oosterlaan, Jaap; Hyde, Christopher; van Meel, Catharina S.; Sergeant, Joseph A.

    2007-01-01

    Background: Both theoretical and clinical accounts of attention-deficit/hyperactivity disorder (ADHD) implicate a dysfunctional reinforcement system. This study investigated heart rate parameters in response to feedback associated with reward and response cost in ADHD children and controls aged 8 to 12. Methods: Heart rate responses (HRRs)…

  6. Heart Rate Variability and Sleep-Related Breathing Disorders in the General Population.

    PubMed

    Aeschbacher, Stefanie; Bossard, Matthias; Schoen, Tobias; Schmidlin, Delia; Muff, Christoph; Maseli, Anna; Leuppi, Jörg D; Miedinger, David; Probst-Hensch, Nicole M; Schmidt-Trucksäss, Arno; Risch, Martin; Risch, Lorenz; Conen, David

    2016-09-15

    Obstructive sleep apnea seems to have an important influence on the autonomic nervous system. In this study, we assessed the relations of sleep apnea-related parameters with 24-hour heart rate variability (HRV) in a large population of young and healthy adults. Participants aged 25 to 41 years with a body mass index <35 kg/m(2) and without known obstructive sleep apnea were included in a prospective population-based cohort study. HRV was assessed using 24-hour electrocardiographic monitoring. The SD of all normal RR intervals (SDNN) was used as the main HRV variable. Apnea-Hypopnea Index (AHI) and oxygen desaturation index (ODI) were obtained from nighttime pulse oximetry with nasal airflow measurements. We defined sleep-related breathing disorders as an AHI ≥5 or an ODI ≥5. Multivariable regression models were constructed to assess the relation of HRV with either AHI or ODI. Median age of the 1,255 participants was 37 years, 47% were men, and 9.6% had an AHI ≥5. Linear inverse associations of SDNN across AHI and ODI groups were found (p for trend = 0.006 and 0.0004, respectively). The β coefficients (95% CI) for the relation between SDNN and elevated AHI were -0.20 (-0.40 to -0.11), p = 0.04 and -0.29 (-0.47 to -0.11), p = 0.002 for elevated ODI. After adjustment for 24-hour heart rate, the same β coefficients (95% CI) were -0.06 (-0.22 to 0.11), p = 0.51 and -0.14 (-0.30 to 0.01), p = 0.07, respectively. In conclusion, even early stages of sleep-related breathing disorders are inversely associated with HRV in young and healthy adults, suggesting that they are tightly linked with autonomic dysfunction. However, HRV and 24-hour heart rate seem to have common information. PMID:27553103

  7. Heart rates of participants in wheelchair sports.

    PubMed

    Coutts, K D

    1988-02-01

    The relative stress of participation in wheelchair basketball, volleyball, tennis, and racquetball were determined by monitoring the heart rates of wheelchair athletes. Heart rates were recorded for 5 seconds every 30 seconds during monitoring sessions of 10 min or longer under game or practice conditions. Subjects were volunteer paraplegic athletes with lesions below T5 or with equivalent disability according to an international sport classification system. Average heart rates were 89 beats/min for tennis 'practice', 96 for racquetball 'practice' 107 for volleyball 'practice', 114 for volleyball 'game', 127 for tennis 'game', 129 for basketball 'practice', 135 for racquetball 'game', and 149 for basketball 'game' conditions. The percentage of time when heart rates were above 140 beats/min, followed the same pattern as the average heart rates and ranged from 0 to 62%.

  8. Once- and twice-daily bevantolol for systemic hypertension using 24-hour ambulatory intraarterial blood pressure recording.

    PubMed

    Al-Khawaja, I M; Caruana, M P; Prince, H; Whittington, J; Raftery, E B

    1986-11-26

    The antihypertensive efficacy of bevantolol, a selective beta 1-adrenoreceptor antagonist, was evaluated in 17 patients with essential hypertension, using continuous ambulatory intraarterial blood pressure (BP) monitoring. The study compared a twice-daily regimen (titrated dose of 200 to 600 mg/day) with the same amount given in a single daily dose. Within-patient comparisons of mean hourly systolic and diastolic BPs and heart rate showed a highly significant effect with twice-daily therapy (p less than 0.001) for all of the 24 hours. Similar significant results were obtained with a single morning dose. There was no difference between the pattern or extent of BP reduction with the 2 regimens. The decrease in BP after bevantolol persisted during the physiologic tests (rest, tilt, isometric and dynamic exercise). Four patients developed minor side effects with the single morning dose, and only 1 patient with the twice-daily regimen. These effects included tiredness, fatigue and dizziness. Unlike pure beta-blocking agents, bevantolol controlled the early morning increase in BP, lending support to the belief that it possesses vasodilatory properties in addition to beta blockade. These results suggest that bevantolol may be useful as first-line therapy in a once-daily dosage for the treatment of essential hypertension.

  9. Heart-rate monitoring by air pressure and causal analysis

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Naoki; Nakajima, Hiroshi; Hata, Yutaka

    2011-06-01

    Among lots of vital signals, heart-rate (HR) is an important index for diagnose human's health condition. For instance, HR provides an early stage of cardiac disease, autonomic nerve behavior, and so forth. However, currently, HR is measured only in medical checkups and clinical diagnosis during the rested state by using electrocardiograph (ECG). Thus, some serious cardiac events in daily life could be lost. Therefore, a continuous HR monitoring during 24 hours is desired. Considering the use in daily life, the monitoring should be noninvasive and low intrusive. Thus, in this paper, an HR monitoring in sleep by using air pressure sensors is proposed. The HR monitoring is realized by employing the causal analysis among air pressure and HR. The causality is described by employing fuzzy logic. According to the experiment on 7 males at age 22-25 (23 on average), the correlation coefficient against ECG is 0.73-0.97 (0.85 on average). In addition, the cause-effect structure for HR monitoring is arranged by employing causal decomposition, and the arranged causality is applied to HR monitoring in a setting posture. According to the additional experiment on 6 males, the correlation coefficient is 0.66-0.86 (0.76 on average). Therefore, the proposed method is suggested to have enough accuracy and robustness for some daily use cases.

  10. Volitional control of the heart rate.

    PubMed

    Abukonna, Ahmed; Yu, Xiaolin; Zhang, Chong; Zhang, Jianbao

    2013-11-01

    The heart rate is largely under control of the autonomic nervous system. The aim of the present study is to investigate the interactions between the brain and heart underlying volitional control of the heart and to explore the effectiveness of volition as a strategy to control the heart rate without biofeedback. Twenty seven healthy male subjects voluntarily participated in the study and were instructed to decrease and increase their heart beats according to rhythmic, computer generated sound either 10% faster or slower than the subjects' measured heart rate. Sympathetic and parasympathetic activities were estimated with the heart rate variability (HRV) obtained by power spectral analysis of RR intervals. Functional coupling patterns of cerebral cortex with the heart were determined by Partial directed coherence (PDC). In HR(slow) task; HR and sympathetic activity significantly decreased. However parasympathetic activity and power spectral density of EEG in low Alpha (8-10.5 Hz) band significantly increased. Moreover information flow from parietal area (P3 and P4) to RR interval significantly increased. During HR(quick) task; HR, sympathetic activity and power spectral density of EEG in low Beta (14-24 Hz) band significantly increased. Parasympathetic activity significantly decreased. Information flow from FT8, CZ and T8 electrodes to RR interval significantly increased. Our findings suggested that the heart beat can be controlled by volition and is related to some special areas in the cortex.

  11. The Relationship between Serum Lipid Fractions and Heart Rate Variability in Diabetic Patients with Statin Therapy

    PubMed Central

    BADEA, ANAMARIA RALUCA; NEDELCU, LAURENTIU; VALEANU, MADALINA; ZDRENGHEA, DUMITRU

    2014-01-01

    Background and aims The aim of this study is to identify and highlight the relationship between serum lipid fractions and heart rate variability in diabetic patients receiving statin therapy. Patients and methods The study was performed in a group of 87 type 2 diabetic patients on statin associated therapy. All patients were on Holter ECG 24 hours monitored with three channel monitor (Labtech ECG Holter monitor), and data were analyzed on a commercially available software (Cardiospy PC SW/EV 5.02.06.02). Concentrations of biochemical parameters were determined using specific enzymatic assays on an autoanalyzer Olympus AU 680. In the studied patients, we analyzed Holter/24 hours monitoring reports with respect to heart rate variability indexes, arrhythmic events and myocardial ischemia. Results It was noticed that the mean values of serum TG were slightly elevated, TC levels were close to the limits specified by the guidelines for diabetic patients and for patients with cardiovascular diseases, with no significant differences between males and females. After analyzing the HRV in both time and frequency domains, we found no strong correlations between any of the HRV indexes and any of the lipid fractions. Conclusions The results suggest that statin therapy may reduce the autonomic impairment secondary to dyslipidemia. PMID:26528015

  12. Baroreceptor-heart rate reflex function before and after surgical reversal of two-kidney, one-clip hypertension in the rat.

    PubMed

    Edmunds, M E; Russell, G I; Burton, P R; Swales, J D

    1990-06-01

    Baroreflex function was studied in conscious early phase (less than 6 weeks) two-kidney, one-clip hypertensive rats before and 24 hours after surgical reversal of hypertension by removal of the constricting renal artery clip or after pharmacological reduction of blood pressure by an infusion of hydralazine or captopril. A normotensive sham-clipped group was included. Another group of two-kidney, one-clip rats was studied 3 weeks after unclipping. Baroreflex sensitivity, as assessed by the steady-state method using a graded phenylephrine infusion, mean arterial pressure, and heart rate were measured preoperatively and at 24 hours postoperatively. Two-kidney, one-clip rats were significantly hypertensive preoperatively compared with control (mean arterial pressure, 183 +/- 4 vs. 106 +/- 2 mm Hg, p less than 0.001), heart rate was similar (420 +/- 9 vs. 401 +/- 9 beats/min, p greater than 0.05), and baroreflex sensitivity was significantly reduced (0.76 +/- 0.07 vs. 1.50 +/- 0.20 msec/mm Hg; p less than 0.001). There was a minimal change in heart rate despite the fall in mean arterial pressure in all hypertensive groups, indicating resetting of the baroreflexes. At 24 hours after the operation, baroreflex sensitivity was unchanged in all groups compared with the preoperative value. By 3 weeks, baroreflex sensitivity was significantly greater than in the hypertensive two-kidney, one-clip rats before the operation and 24 hours after they were unclipped, but not compared with normotensive sham-clipped rats. Thus, although resetting occurs within 24 hours, whatever the method of blood pressure reduction, baroreflex sensitivity remains impaired at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Heart Rate and Respiratory Rate Influence on Heart Rate Variability Repeatability: Effects of the Correction for the Prevailing Heart Rate

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Zieliński, Jakub; Przybylski, Jacek

    2016-01-01

    Background: Since heart rate variability (HRV) is associated with average heart rate (HR) and respiratory rate (RespRate), alterations in these parameters may impose changes in HRV. Hence the repeatability of HRV measurements may be affected by differences in HR and RespRate. The study aimed to evaluate HRV repeatability and its association with changes in HR and RespRate. Methods: Forty healthy volunteers underwent two ECG examinations 7 days apart. Standard HRV indices were calculated from 5-min ECG recordings. The ECG-derived respiration signal was estimated to assess RespRate. To investigate HR impact on HRV, HRV parameters were corrected for prevailing HR. Results: Differences in HRV parameters between the measurements were associated with the changes in HR and RespRate. However, in multiple regression analysis only HR alteration proved to be independent determinant of the HRV differences—every change in HR by 1 bpm changed HRV values by 16.5% on average. After overall removal of HR impact on HRV, coefficients of variation of the HRV parameters significantly dropped on average by 26.8% (p < 0.001), i.e., by the same extent HRV reproducibility improved. Additionally, the HRV correction for HR decreased association between RespRate and HRV. Conclusions: In stable conditions, HR but not RespRate is the most powerful factor determining HRV reproducibility and even a minimal change of HR may considerably alter HRV. However, the removal of HR impact may significantly improve HRV repeatability. The association between HRV and RespRate seems to be, at least in part, HR dependent. PMID:27588006

  14. FPGA Implementation of Heart Rate Monitoring System.

    PubMed

    Panigrahy, D; Rakshit, M; Sahu, P K

    2016-03-01

    This paper describes a field programmable gate array (FPGA) implementation of a system that calculates the heart rate from Electrocardiogram (ECG) signal. After heart rate calculation, tachycardia, bradycardia or normal heart rate can easily be detected. ECG is a diagnosis tool routinely used to access the electrical activities and muscular function of the heart. Heart rate is calculated by detecting the R peaks from the ECG signal. To provide a portable and the continuous heart rate monitoring system for patients using ECG, needs a dedicated hardware. FPGA provides easy testability, allows faster implementation and verification option for implementing a new design. We have proposed a five-stage based methodology by using basic VHDL blocks like addition, multiplication and data conversion (real to the fixed point and vice-versa). Our proposed heart rate calculation (R-peak detection) method has been validated, using 48 first channel ECG records of the MIT-BIH arrhythmia database. It shows an accuracy of 99.84%, the sensitivity of 99.94% and the positive predictive value of 99.89%. Our proposed method outperforms other well-known methods in case of pathological ECG signals and successfully implemented in FPGA.

  15. FPGA Implementation of Heart Rate Monitoring System.

    PubMed

    Panigrahy, D; Rakshit, M; Sahu, P K

    2016-03-01

    This paper describes a field programmable gate array (FPGA) implementation of a system that calculates the heart rate from Electrocardiogram (ECG) signal. After heart rate calculation, tachycardia, bradycardia or normal heart rate can easily be detected. ECG is a diagnosis tool routinely used to access the electrical activities and muscular function of the heart. Heart rate is calculated by detecting the R peaks from the ECG signal. To provide a portable and the continuous heart rate monitoring system for patients using ECG, needs a dedicated hardware. FPGA provides easy testability, allows faster implementation and verification option for implementing a new design. We have proposed a five-stage based methodology by using basic VHDL blocks like addition, multiplication and data conversion (real to the fixed point and vice-versa). Our proposed heart rate calculation (R-peak detection) method has been validated, using 48 first channel ECG records of the MIT-BIH arrhythmia database. It shows an accuracy of 99.84%, the sensitivity of 99.94% and the positive predictive value of 99.89%. Our proposed method outperforms other well-known methods in case of pathological ECG signals and successfully implemented in FPGA. PMID:26643079

  16. Prediction of Appropriate Shocks Using 24-Hour Holter Variables and T-Wave Alternans After First Implantable Cardioverter-Defibrillator Implantation in Patients With Ischemic or Nonischemic Cardiomyopathy.

    PubMed

    Seegers, Joachim; Bergau, Leonard; Expósito, Pascal Muñoz; Bauer, Axel; Fischer, Thomas H; Lüthje, Lars; Hasenfuß, Gerd; Friede, Tim; Zabel, Markus

    2016-07-01

    In patients treated with implantable cardioverter defibrillator (ICD), prediction of both overall survival and occurrence of shocks is important if improved patient selection is desired. We prospectively studied the predictive value of biomarkers and indexes of cardiac and renal function and spectral microvolt T-wave alternans testing and 24-hour Holter variables in a population who underwent first ICD implantation. Consecutive patients in sinus rhythm with ischemic or dilated cardiomyopathy scheduled for primary or secondary prophylactic ICD implantation were enrolled. Exercise microvolt T-wave alternans and 24-hour Holter for number of ventricular premature contractions (VPCs), deceleration capacity, heart rate variability, and heart rate turbulence were done. Death of any cause and first appropriate ICD shock were defined as end points. Over 33 ± 15 months of follow-up, 36 of 253 patients (14%) received appropriate shocks and 39 of 253 patients (15%) died. Only 3 of 253 patients (1%) died after receiving at least 1 appropriate shock. In univariate analyses, New York Heart Association class, ejection fraction, N-terminal pro brain-type natriuretic peptide (NT-proBNP), renal function, ICD indication, deceleration capacity, heart rate variability, and heart rate turbulence were predictive of all-cause mortality and VPC number and deceleration capacity predicted first appropriate shock. NT-proBNP (≥1,600 pg/ml) was identified as the only independent predictor of all-cause mortality (hazard ratio 3.0, confidence interval 1.3 to 7.3, p = 0.014). In contrast, VPC number predicted appropriate shocks (hazard ratio 2.3, confidence interval 1.0 to 5.5, p = 0.047) as the only independent risk marker. In conclusion, NT-proBNP is a strong independent predictor of mortality in a typical prospective cohort of newly implanted patients with ICD, among many electrocardiographic and clinical variables studied. Number of VPCs was identified as a predictor of appropriate shocks

  17. Fetal Heart Rate Response to Maternal Exercise.

    PubMed

    Monga, Manju

    2016-09-01

    Current guidelines regarding recommended exercise in pregnancy appear consistent with reported research regarding fetal heart changes in response to maternal exercise. Fetal heart rate increases during pregnancy, but maternal exercise appears well tolerated if performed in uncomplicated pregnancies and not in the supine position. Maximal levels of exercise that are well tolerated by the fetus have not yet been well defined; however, recent literature suggests that sustained exercise during pregnancy may have beneficial effects on autonomic control of fetal heart rate and variability that may lead to long-term health benefits. PMID:27388963

  18. Elevated heart rate and nondipping heart rate as potential targets for melatonin: a review.

    PubMed

    Simko, Fedor; Baka, Tomas; Paulis, Ludovit; Reiter, Russel J

    2016-09-01

    Elevated heart rate is a risk factor for cardiovascular and all-cause mortalities in the general population and various cardiovascular pathologies. Insufficient heart rate decline during the night, that is, nondipping heart rate, also increases cardiovascular risk. Abnormal heart rate reflects an autonomic nervous system imbalance in terms of relative dominance of sympathetic tone. There are only a few prospective studies concerning the effect of heart rate reduction in coronary heart disease and heart failure. In hypertensive patients, retrospective analyses show no additional benefit of slowing down the heart rate by beta-blockade to blood pressure reduction. Melatonin, a secretory product of the pineal gland, has several attributes, which predict melatonin to be a promising candidate in the struggle against elevated heart rate and its consequences in the hypertensive population. First, melatonin production depends on the sympathetic stimulation of the pineal gland. On the other hand, melatonin inhibits the sympathetic system in several ways representing potentially the counter-regulatory mechanism to normalize excessive sympathetic drive. Second, administration of melatonin reduces heart rate in animals and humans. Third, the chronobiological action of melatonin may normalize the insufficient nocturnal decline of heart rate. Moreover, melatonin reduces the development of endothelial dysfunction and atherosclerosis, which are considered a crucial pathophysiological disorder of increased heart rate and pulsatile blood flow. The antihypertensive and antiremodeling action of melatonin along with its beneficial effects on lipid profile and insulin resistance may be of additional benefit. A clinical trial investigating melatonin actions in hypertensive patients with increased heart rate is warranted.

  19. Heart Rate Sensor for Freshwater Mussels

    NASA Astrophysics Data System (ADS)

    Just, C. L.; Vial, D. P.; Kruger, A.; Niemeier, J. J.; Lee, H. W.; Schroer, H. W.

    2014-12-01

    Researchers have long been interested the cardiac activity of mollusks. First, it is important as a basic measure of the animal's metabolism. Further, activities such as feeding and burrowing affect heart rate, as do environmental factors such as water salinity, water temperature, exposure, and predation. We have developed a small, noninvasive sensor for measuring freshwater mussel heart rate. Its working principle is as follows. An infrared (IR) light-emitting diode is placed in contact with the mussel shell. Some of the IR penetrates through the shell, reflects off internal organs, and traverses back. A photodetector detects this IR, and electronics condition the signal. The heartbeat of the animal modulates the IR, allowing one to measure the heart rate. The technique is widely-used in finger heart-rate monitors in humans. The sensors do not have to be positioned above the heart and several locations on the mussel shell work well. The sensor is small (8 mm × 10 mm) and consumes less than 1 mA, and has a simple one-wire interface that allows for easy integration into data acquisition hardware. We present heart rate measurements for the common pocketbook (lampsilis cardium) freshwater mussel.

  20. A 24-Hour Study of the Hypothalamo-Pituitary Axes in Huntington’s Disease

    PubMed Central

    Nambron, Rajasree; Costelloe, Seán J.; Martin, Nicholas G.; Hill, Nathan R.; Frost, Chris; Watt, Hilary C.; Hindmarsh, Peter; Björkqvist, Maria; Warner, Thomas T.

    2015-01-01

    Background Huntington’s disease is an inherited neurodegenerative disorder characterised by motor, cognitive and psychiatric disturbances. Patients exhibit other symptoms including sleep and mood disturbances, muscle atrophy and weight loss which may be linked to hypothalamic pathology and dysfunction of hypothalamo-pituitary axes. Methods We studied neuroendocrine profiles of corticotropic, somatotropic and gonadotropic hypothalamo-pituitary axes hormones over a 24-hour period in controlled environment in 15 healthy controls, 14 premanifest and 13 stage II/III Huntington’s disease subjects. We also quantified fasting levels of vasopressin, oestradiol, testosterone, dehydroepiandrosterone sulphate, thyroid stimulating hormone, free triiodothyronine, free total thyroxine, prolactin, adrenaline and noradrenaline. Somatotropic axis hormones, growth hormone releasing hormone, insulin-like growth factor-1 and insulin-like factor binding protein-3 were quantified at 06:00 (fasting), 15:00 and 23:00. A battery of clinical tests, including neurological rating and function scales were performed. Results 24-hour concentrations of adrenocorticotropic hormone, cortisol, luteinizing hormone and follicle-stimulating hormone did not differ significantly between the Huntington’s disease group and controls. Daytime growth hormone secretion was similar in control and Huntington’s disease subjects. Stage II/III Huntington’s disease subjects had lower concentration of post-sleep growth hormone pulse and higher insulin-like growth factor-1:growth hormone ratio which did not reach significance. In Huntington’s disease subjects, baseline levels of hypothalamo-pituitary axis hormones measured did not significantly differ from those of healthy controls. Conclusions The relatively small subject group means that the study may not detect subtle perturbations in hormone concentrations. A targeted study of the somatotropic axis in larger cohorts may be warranted. However, the lack

  1. Evaluation of the indications and arrhythmic patterns of 24 hour Holter electrocardiography among hypertensive and diabetic patients seen at OAUTHC, Ile-Ife Nigeria

    PubMed Central

    Adebayo, Rasaaq A; Ikwu, Amanze N; Balogun, Michael O; Akintomide, Anthony O; Mene-Afejuku, Tuoyo O; Adeyeye, Victor O; Bamikole, Olaniyi J; Bisiriyu, Luqman A; Ajayi, Olufemi E; Ogunyemi, Suraj A; Oketona, Omolola A

    2014-01-01

    Background There are very limited published studies in Nigeria on the use of 24 hour Holter electrocardiogram (Holter ECG) in the arrhythmic evaluation of hypertensive and diabetic patients. Objective To evaluate indications, arrhythmic pattern of Holter ECG, and heart rate variability (HRV) among patients with hypertensive heart disease (HHD) with or without heart failure and type 2 diabetes mellitus (T2DM) seen in our cardiac care unit. Methods Seventy-nine patients (32 males and 47 females) were studied consecutively over a year using Schiller type (MT-101) Holter ECG machine. Results Out of the 79 patients, 17 (21.5%) had HHD without heart failure, 33 (41.8%) had HHD with hypertensive heart failure (HHF), while 29 (36.7%) were T2DM patients. The mean (standard deviation) ages of HHD without heart failure, HHF and T2DM patients were 59.65 (±14.38), 65.15 (±14.30), and 54.66 (±8.88) respectively. The commonest indication for Holter ECG was palpitation (38%), followed by syncope (20.3%). Premature ventricular contraction was the commonest arrhythmic pattern among the 79 patients, especially among HHF patients. The HRV using standard deviation of all normal-normal intervals was significantly reduced in T2DM patients (81.03±26.33, confidence interval [CI] =71.02–91.05) compared to the HHD without heart failure (119.65±29.86, CI =104.30–135.00) and HHF (107.03±62.50, CI =84.00–129.19). There was a negative correlation between the duration of T2DM and HRV (r=−0.613). Conclusion Palpitation was the commonest Holter ECG indication and premature ventricular contractions were the commonest arrhythmic pattern among our patients. HRV was reduced in T2DM patients compared with hypertensive patients. PMID:25473303

  2. Influence of basic heart rate and sex on heart rate turbulence in healthy subjects.

    PubMed

    Schwab, Jörg O; Eichner, Gerrit; Veit, Gudrun; Schmitt, Heiko; Lewalter, Thorsten; Lüderitz, Berndt

    2004-12-01

    Acceleration and deceleration of the heart rate after the occurrence of a ventricular premature complex is characterized as heart rate turbulence (HRT). Two parameters quantify heart rate turbulence: onset and slope. The physiological properties have not been clarified in a large cohort of persons yet. This study evaluated properties of HRT, and focused on the influence of basic heart rate and sex on HRT. Using a special protocol, 95 persons were studied prospectively. HRT and its physiological properties were determined in 95 persons using Holter ECGs. The authors found 24% with a turbulence onset 0% and 5% with a turbulence slope <2.5 ms/RRI. Mean heart rate during Holter differed significantly between women and men (745 vs 817 ms, P < 0.0001). A linear, weighted regression model revealed that an increased heart rate before a ventricular premature complex is associated with a decreased turbulence onset (P < 0.0001). Turbulence slope was attenuated by basic heart rate only in men (P = 0.0022). On the contrary, the study detected no influence of the basic heart rate on turbulence slope in women (P = 0.0015 for the comparison between women and men). Basic heart rate and sex show an influence on HRT and should be considered when using HRT for noninvasive risk stratification.

  3. Effects of electromagnetic radiation (bright light, extremely low-frequency magnetic fields, infrared radiation) on the circadian rhythm of melatonin synthesis, rectal temperature, and heart rate.

    PubMed

    Griefahn, Barbara; Künemund, Christa; Blaszkewicz, Meinolf; Lerchl, Alexander; Degen, Gisela H

    2002-10-01

    Electromagnetic spectra reduce melatonin production and delay the nadirs of rectal temperature and heart rate. Seven healthy men (16-22 yrs) completed 4 permuted sessions. The control session consisted of a 24-hours bedrest at < 30 lux, 18 degrees C, and < 50 dBA. In the experimental sessions, either light (1500 lux), magnetic field (16.7 Hz, 0.2 mT), or infrared radiation (65 degrees C) was applied from 5 pm to 1 am. Salivary melatonin level was determined hourly, rectal temperature and heart rate were continuously recorded. Melatonin synthesis was completely suppressed by light but resumed thereafter. The nadirs of rectal temperature and heart rate were delayed. The magnetic field had no effect. Infrared radiation elevated rectal temperature and heart rate. Only bright light affected the circadian rhythms of melatonin synthesis, rectal temperature, and heart rate, however, differently thus causing a dissociation, which might enhance the adverse effects of shiftwork in the long run.

  4. [Hypoxaemia, peripheral chemoreceptors and fetal heart rate].

    PubMed

    Secourgeon, J-F

    2012-02-01

    The perinatal results of the widespread adoption of the continuous electronic fetal heart rate monitoring during labor remain rather disappointing. This is due in part to a lack of consistent interpretation of the fetal heart tracings. Despite efforts by referral agencies over the past decade the situation has not improved. In defense of practitioners the heterogeneity and complexity of definitions and classifications patterns especially morphological currently proposed should be noted. Whereas with the recent advances in the field of neuroscience, it is now possible to visualize the chain of pathophysiological events that lead from the hypoxemic stimulus of the glomus cell to changes in the morphology of the fetal heart rate tracing. Thus by taking some examples of real situations, we propose a method of analysis that dissects the fetal heart tracing and take into account the functional specifications of the chemoreceptor when exposed to a hypoxic environment. Furthermore we can identify tracings with a "threshold effect" and also "sensitization and desensitization effects" according to the intensity, duration and recurrence of hypoxaemic episodes. This new approach based upon specific research into the mechanism behind the fetal heart rate abnormalities may be useful to complement the morphological study of the fetal heart tracing, to provide a better idea of the fetal status and to better define the indications of fetal blood sampling procedures.

  5. Stochastic model for heart-rate fluctuations

    NASA Astrophysics Data System (ADS)

    Kuusela, Tom; Shepherd, Tony; Hietarinta, Jarmo

    2003-06-01

    A normal human heart rate shows complex fluctuations in time, which is natural, because the heart rate is controlled by a large number of different feedback control loops. These unpredictable fluctuations have been shown to display fractal dynamics, long-term correlations, and 1/f noise. These characterizations are statistical and they have been widely studied and used, but much less is known about the detailed time evolution (dynamics) of the heart-rate control mechanism. Here we show that a simple one-dimensional Langevin-type stochastic difference equation can accurately model the heart-rate fluctuations in a time scale from minutes to hours. The model consists of a deterministic nonlinear part and a stochastic part typical to Gaussian noise, and both parts can be directly determined from the measured heart-rate data. Studies of 27 healthy subjects reveal that in most cases, the deterministic part has a form typically seen in bistable systems: there are two stable fixed points and one unstable one.

  6. Heart-rate pulse-shift detector

    NASA Technical Reports Server (NTRS)

    Anderson, M.

    1974-01-01

    Detector circuit accurately separates and counts phase-shift pulses over wide range of basic pulse-rate frequency, and also provides reasonable representation of full repetitive EKG waveform. Single telemeter implanted in small animal monitors not only body temperature but also animal movement and heart rate.

  7. The Effects of Thoracic Sympathotomy on Heart Rate Variability in Patients with Palmar Hyperhidrosis

    PubMed Central

    Zhang, Tong-yuan; Xu, Jin-jin

    2012-01-01

    Purpose To observe the evolution of heart rate variability (HRV) in patients with palmar hyperhidrosis before and after endoscopic thoracic sympathotomy and to evaluate the effects of the surgery on the autonomic nervous system. Materials and Methods Endoscopic thoracic sympathotomy was performed on 20 patients with palmar hyperhidrosis. The thoracic sympathetic chain at the level of the third to fourth rib (R3-R4) was transected, but the ganglia were left in position without removal. A slightly larger ramus, in comparison to the other rami, that arose laterally from the sympathetic chain was interrupted to achieve adequate sympathetic denervation of the upper extremity. Before and on the day after the surgery, 24-hour Holter Electrocardiograph was performed, obtaining time domain and frequency domain parameters. Results Compared with preoperative variables, there was a significant increase in the number of adjacent normal R wave to R wave (R-R) intervals that differed by more than 50 ms, as percent of the total number of normal RR intervals (pNN50); root mean square difference, the square root of the mean of the sum of squared differences between adjacent normal RR intervals over the entire 24-hour recording; standard deviation of the average normal RR interval for all 5-minute segments of a 24-hour recording (SDANN) after thoracic sympathotomy. Low frequencies (LF, 0.04 to 0.15 Hz) decreased significantly. There was no statistical difference in high frequencies (HF, 0.15 to 0.40 Hz), LF/HF ratio (LF/HF), or standard deviation for all normal RR intervals for the entire 24-h recording (SDNN) before and after thoracic sympathotomy. Conclusion There was a significant improvement in HRV in patients with palmar hyperhidrosis after thoracic sympathotomy. This may be attributable to an improvement autonomic nervous system balance and parasympathetic predominance in the early postoperative stage. PMID:23074105

  8. Resting Heart Rate and Auditory Evoked Potential

    PubMed Central

    Fiuza Regaçone, Simone; Baptista de Lima, Daiane Damaris; Engrácia Valenti, Vitor; Figueiredo Frizzo, Ana Cláudia

    2015-01-01

    The objective of this study was to evaluate the association between rest heart rate (HR) and the components of the auditory evoked-related potentials (ERPs) at rest in women. We investigated 21 healthy female university students between 18 and 24 years old. We performed complete audiological evaluation and measurement of heart rate for 10 minutes at rest (heart rate monitor Polar RS800CX) and performed ERPs analysis (discrepancy in frequency and duration). There was a moderate negative correlation of the N1 and P3a with rest HR and a strong positive correlation of the P2 and N2 components with rest HR. Larger components of the ERP are associated with higher rest HR. PMID:26504838

  9. Heart Rate Conditioning in Newborn Infants: Relationships Among Conditionability, Heart Rate Variability, and Sex

    ERIC Educational Resources Information Center

    Stamps, Leighton E.; Porges, Stephen W.

    1975-01-01

    Trace conditioning was evaluated in newborn infants by measurements of heart rate responses to a conditioned stimulus in anticipation of or in absence of the unconditioned stimulus. Data suggest females have higher levels of heart rate variability than males, which parallels their greater conditionability. (GO)

  10. Estimation of 24-Hour Intraocular Pressure Peak Timing and Variation Using a Contact Lens Sensor

    PubMed Central

    Liu, John H. K.; Mansouri, Kaweh; Weinreb, Robert N.

    2015-01-01

    Purpose To compare estimates of 24-hour intraocular pressure (IOP) peak timing and variation obtained using a contact lens sensor (CLS) and using a pneumatonometer. Methods Laboratory data collected from 30 healthy volunteers (ages, 20-66 years) in a randomized, controlled clinical trial were analyzed. Participants were housed for 24 hours in a sleep laboratory. One randomly selected right or left eye was fitted with a CLS that monitored circumferential curvature in the corneoscleral region related to the change of IOP. Electronic output signals of 30 seconds were averaged and recorded every 5 minutes. In the contralateral eye, habitual IOP measurements were taken using a pneumatonometer once every two hours. Simulated 24-hour rhythms in both eyes were determined by cosinor fitting. Simulated peak timings (acrophases) and simulated data variations (amplitudes) were compared between the paired eyes. Results Bilateral change patterns of average 24-hour data for the group were in parallel. The simulated peak timing in the CLS fitted eye occurred at 4:44 AM ± 210 min (mean ± SD) and the IOP peak timing in the contralateral eye at 4:11 AM ± 120 min (P=0.256, Wilcoxon signed-rank test). There was no significant correlation between the simulated data variations in the paired eyes (P=0.820, linear regression). Conclusions The 24-hour CLS data showed a simulated peak timing close to the 24-hour IOP peak timing obtained using the pneumatonometer. However, the simulated variations of 24-hour data in the paired eyes were not correlated. Estimated 24-hour IOP rhythms using the two devices should not be considered interchangeable. PMID:26076472

  11. 24-Hour ICH Score Is a Better Predictor of Outcome than Admission ICH Score

    PubMed Central

    Aysenne, Aimee M.; Albright, Karen C.; Mathias, Tiffany; Chang, Tiffany R.; Boehme, Amelia K.; Beasley, T. Mark; Martin-Schild, Sheryl

    2016-01-01

    Background The ICH score is a validated tool for predicting 30-day morbidity and mortality in patients with intracerebral hemorrhage. Aims and/or Hypothesis The aim of this study is to determine if the ICH score calculated 24 hours after admission is a better predictor of mortality than the ICH score calculated on admission. Methods Patients presenting to our center with ICH from 7/08-12/10 were retrospectively identified from our prospective stroke registry. ICH scores were calculated based on initial Glasgow coma scale (GCS) and emergent head computed tomography (CT) on initial presentation and were recalculated after 24 hours. Results A total of 91 patients out of 121 had complete data for admission and 24-hour ICH score. The ICH score changed in 38% from baseline to 24 hours. After adjusting for age, NIHSS on admission, and glucose, ICH score at 24 hours was a significant, independent predictor of mortality (OR = 2.71, 95% CI 1–19–6.20, and P = 0.018), but ICH score on admission was not (OR = 2.14, 95% CI 0.88-5.24, and P = 0.095). Conclusion Early determination of the ICH score may incorrectly estimate the severity and expected outcome after ICH. Calculations of the ICH score 24 hours after admission will better predict early outcomes.

  12. Dissociated 24-hour patterns of somatotropin and prolactin in fatal familial insomnia.

    PubMed

    Portaluppi, F; Cortelli, P; Avoni, P; Vergnani, L; Maltoni, P; Pavani, A; Sforza, E; Manfredini, R; Montagna, P; Roiter, I

    1995-06-01

    To assess the changes in the 24-hour profiles of serum somatotropin and prolactin levels during total disruption of the sleep/wake cycle sustained over several months, we studied 2 subjects affected by fatal familial insomnia, a rare disease characterized by selective thalamic degeneration that causes chronic sleep loss. Under standardized conditions and polysomnographic control, the patients underwent repeated 24-hour study sessions covering the entire clinical course of the disease. Hormones were assayed at 30-min intervals. Four healthy volunteers were used as controls. A sleep/wake cycle was always absent in fatal familial insomnia. Serum somatotropin and prolactin concentrations never exceeded the normal range of variation. The nocturnal elevation of somatotropin disappeared simultaneously with sleep loss, whereas a significant 24-hour component of variations in serum prolactin levels was present for months after total disruption of the sleep/wake cycle, with normally placed nocturnal acrophases. Complete obliteration of the 24-hour component was achieved for prolactin only in the advanced stages, through a progressive decrease in 24-hour amplitude of variation. Selective and progressive degeneration of the mediodorsal and anterior ventral nuclei of the thalamus causes an early obliteration of the 24-hour rhythm of somatotropin and a later disappearance of circadian prolactin rhythmicity.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Estimation of heart rate and heart rate variability from pulse oximeter recordings using localized model fitting.

    PubMed

    Wadehn, Federico; Carnal, David; Loeliger, Hans-Andrea

    2015-08-01

    Heart rate variability is one of the key parameters for assessing the health status of a subject's cardiovascular system. This paper presents a local model fitting algorithm used for finding single heart beats in photoplethysmogram recordings. The local fit of exponentially decaying cosines of frequencies within the physiological range is used to detect the presence of a heart beat. Using 42 subjects from the CapnoBase database, the average heart rate error was 0.16 BPM and the standard deviation of the absolute estimation error was 0.24 BPM. PMID:26737125

  14. Heart rate variability in Chinchilla rabbits.

    PubMed

    Nadareishvili, K Sh; Meskhishvili, I I; Kakhiani, D D; Ormotsadze, G L; Nazarishvili, G T; Gvasalia, M G; Khvedelidze, M T; Sandodze, V Ya

    2002-12-01

    Temporal and spectral parameters of heart rate variability were studied as criteria for classification of mature Chinchilla rabbit population according to their basal neurovegetative status. The absolute values of total spectral power density and individual frequency bands differed significantly in vagotonics and sympathotonics. However, standardized spectral power distributions in high-, low- and very low-frequency ranges were similar in both groups. Our results suggest that the intensity of regulatory influences on the heart at all levels of regulation, which can be evaluated by spectral analysis, is similarly distributed in both groups. Hence, the observed differences in the heart rate variability can not be explained by peculiarities in sympathovagal balance, but are determined by more universal mechanisms. PMID:12660841

  15. Current clinical applications of heart rate variability.

    PubMed

    Stys, A; Stys, T

    1998-10-01

    Heart rate variability (HRV) has become a popular method for the studies of physiologic mechanisms responsible for the control of heart rate fluctuations, in which the autonomic nervous system appears to play a primary role. Depression of HRV has been observed in many clinical scenarios, including autonomic neuropathy, heart transplantation, congestive heart failure, myocardial infarction (MI), and other cardiac and noncardiac diseases. However, it is important to realize that clinical implication of HRV analysis has been clearly recognized in only two clinical conditions: (1) as a predictor of risk of arrhythmic events or sudden cardiac death after acute MI, and (2) as a clinical marker of evolving diabetic neuropathy. Recently, its role in evaluation and management of heart failure has also been recognized. It is pertinent to recognize the limitations of HRV as far as its clinical utility at present is concerned. The methodology of HRV had remained poorly standardized until the recent publication of the Special Report of the Task Force of ESC/NASPE, and thus has been presenting difficulty in comparing earlier existing data. Also, determination of the exact sensitivity, specificity, and predictive value of HRV, as well as the normal values of standard measures in the general population, still require further investigation before better standards can be set for existing and future clinical applications. This article reviews the major concepts of HRV measurements, their clinical relevance, and the recent advances in this field. PMID:9789691

  16. Neonatal family care for 24 hours per day: effects on maternal confidence and breast-feeding.

    PubMed

    Wataker, Heidi; Meberg, Alf; Nestaas, Eirik

    2012-01-01

    In family care (FC) program for neonatal intensive care units (NICUs), parents are encouraged to reside together with their infant for 24 hours a day to actively be involved in the care. The aim of this study was to assess the impact of FC on maternal confidence and breast-feeding. Maternal confidence and rate of breast-feeding were assessed in 31 mothers offered FC that included special family rooms in the NICU, and in 30 mothers from a comparable NICU providing traditional care without such facilities. One week prior to hospital discharge, mothers in the FC group felt better informed regarding nursing issues and had more confidence in interpretation of the infants regarding feeding issues and in caregiving without staff attendance (P < .05). They also reported a higher level of empowerment (P < .05). Three months after discharge, the mothers in the FC group had a higher self-reported skill level for interpretation of the infant's signals and knowledge about breast-feeding (P < .05). Despite similar rate of breast-feeding at discharge, more infants in the FC group were breastfed 3 months after discharge (P < .05). An FC program in the NICU promoted better maternal confidence during the hospital stay and 3 months after discharge compared with traditional care.

  17. Methodology for adding glycemic index and glycemic load values to 24-hour dietary recall database

    PubMed Central

    Olendzki, Barbara C.; Ma, Yunsheng; Culver, Annie L.; Ockene, Ira S.; Griffith, Jennifer A.; Hafner, Andrea R.; Hebert, James R.

    2006-01-01

    Objectives We describe a method of adding the glycemic index (GI) and glycemic load (GL) values to the nutrient database of the 24-hour dietary recall interview (24HR), a widely used dietary assessment. We also calculated daily GI and GL values from the 24HR. Methods Subjects were 641 healthy adults from central Massachusetts who completed 9067 24HRs. The 24HR-derived food data were matched to the International Table of Glycemic Index and Glycemic Load Values. The GI values for specific foods not in the table were estimated against similar foods according to physical and chemical factors that determine GI. Mixed foods were disaggregated into individual ingredients. Results Of 1261 carbohydrate-containing foods in the database, GI values of 602 foods were obtained from a direct match (47.7%), accounting for 22.36% of dietary carbohydrate. GI values from 656 foods (52.1%) were estimated, contributing to 77.64% of dietary carbohydrate. The GI values from three unknown foods (0.2%) could not be assigned. The average daily GI was 84 (SD 5.1, white bread as referent) and the average GL was 196 (SD 63). Conclusion Using this methodology for adding GI and GL values to nutrient databases, it is possible to assess associations between GI and/or GL and body weight and chronic disease outcomes (diabetes, cancer, heart disease). This method can be used in clinical and survey research settings where 24HRs are a practical means for assessing diet. The implications for using this methodology compel a broader evaluation of diet with disease outcomes. PMID:17029903

  18. Computer simulation of the effect of dDAVP with saline loading on fluid balance after 24-hour head-down tilt

    NASA Technical Reports Server (NTRS)

    Srinivasan, R. S.; Simanonok, K. E.; Charles, J. B.

    1994-01-01

    Fluid loading (FL) before Shuttle reentry is a countermeasure currently in use by NASA to improve the orthostatic tolerance of astronauts during reentry and postflight. The fluid load consists of water and salt tablets equivalent to 32 oz (946 ml) of isotonic saline. However, the effectiveness of this countermeasure has been observed to decrease with the duration of spaceflight. The countermeasure's effectiveness may be improved by enhancing fluid retention using analogs of vasopressin such as lypressin (LVP) and desmopressin (dDAVP). In a computer simulation study reported previously, we attempted to assess the improvement in fluid retention obtained by the use of LVP administered before FL. The present study is concerned with the use of dDAVP. In a recent 24-hour, 6 degree head-down tilt (HDT) study involving seven men, dDAVP was found to improve orthostatic tolerance as assessed by both lower body negative pressure (LBNP) and stand tests. The treatment restored Luft's cumulative stress index (cumulative product of magnitude and duration of LBNP) to nearly pre-bedrest level. The heart rate was lower and stroke volume was marginally higher at the same LBNP levels with administration of dDAVP compared to placebo. Lower heart rates were also observed with dDAVP during stand test, despite the lower level of cardiovascular stress. These improvements were seen with only a small but significant increase in plasma volume of approximately 3 percent. This paper presents a computer simulation analysis of some of the results of this HDT study.

  19. 24-hour central blood pressure and intermediate cardiovascular phenotypes in untreated subjects

    PubMed Central

    Bednarek, Agnieszka; Jankowski, Piotr; Olszanecka, Agnieszka; Windak, Adam; Kawecka-Jaszcz, Kalina; Czarnecka, Danuta

    2014-01-01

    Background: Recently, 24-hour monitoring of central systolic blood pressure (SBP) has become available. However, the relation between end-organ damage and the 24-hour central SBP profile and variability has not so far been analyzed. Therefore, the aim of this cross-sectional study was to evaluate the relation between 24-hour central SBP, 24-hour central SBP profile as well as central SBP short-term variability and parameters of cardiac and vascular intermediate phenotypes. Methods: The study group consisted of 50 patients with newly diagnosed, untreated hypertension (age 40.4 ± 11.5 years, 35 men) and 50 normotensive subjects (age 38.3 ± 12.0 years, 35 men). Applanation tonometry of the radial artery and the “n-point forward moving average” method were used to determine 24-hour central SBP. Each study participant underwent echocardiography and carotid ultrasonography. Results: 24-hour, daytime, and nighttime central SBP was related to left ventricle end-diastole diameter (p < 0.05), left ventricular mass index (p < 0.001), relative wall thickness (p < 0.05), E/E’ ratio (p < 0.01), and left atrium volume (p < 0.01). The nocturnal central SBP fall was not related to any of the mentioned parameters, whereas parameters of short-term variability were related to IMT in hypertensives only (p < 0.05). Conclusions: The present study showed that 24-hour central SBP is related to intermediate cardiac phenotypes as assessed by echocardiography whereas short-term central SBP variability is mainly related to vascular phenotype as determined by IMT. PMID:25628959

  20. Heart rate detection from plantar bioimpedance measurements.

    PubMed

    González Landaeta, R; Casas, O; Pallàs-Areny, R

    2006-01-01

    The heart rate is a basic health indicator, useful in both clinical measurements and home health care. Current home care systems often require the attachment of electrodes or other sensors to the body, which can be cumbersome to the patient. Moreover, some measurements are sensitive to movement artifacts, are not user-friendly and require a specialized supervision. In this paper, a novel technique for heart rate measurement for a standing subject is proposed, which is based on plantar bioimpedance measurements, such as those performed by some bathroom weighting scales for body composition analysis. Because of the low level of heart-related impedance variations, the measurement system has a gain of 1400. We have implemented a fully differential AC amplifier with a common-mode rejection ratio (CMRR) of 105 dB at 10 kHz. Coherent demodulation based on synchronous sampling yields a signal-to-noise ratio (SNR) of 55 dB. The system has a sensitivity of 1.9 V/Omega. The technique has been demonstrated on 18 volunteers, whose bioimpedance signal and ECG were simultaneously measured to validate the results. The average cross-correlation coefficient between the heart rates determined from these two signals was 0.998 (std. dev. 0.001). PMID:17946677

  1. Lessons from the Heart: Individualizing Physical Education with Heart Rate Monitors.

    ERIC Educational Resources Information Center

    Kirkpatrick, Beth; Birnbaum, Burton H.

    Learning about the relationship between heart rate and physical activity is an important aspect of fitness education. Use of a heart rate monitor (HRM) helps a student to understand how stretching and large muscle movements gradually increase the heart rate and blood flow, and enables students to measure their exercise heart rates and set goals…

  2. Severe community-acquired pneumonia: timely management measures in the first 24 hours.

    PubMed

    Phua, Jason; Dean, Nathan C; Guo, Qi; Kuan, Win Sen; Lim, Hui Fang; Lim, Tow Keang

    2016-01-01

    Mortality rates for severe community-acquired pneumonia (CAP) range from 17 to 48 % in published studies.In this review, we searched PubMed for relevant papers published between 1981 and June 2016 and relevant files. We explored how early and aggressive management measures, implemented within 24 hours of recognition of severe CAP and carried out both in the emergency department and in the ICU, decrease mortality in severe CAP.These measures begin with the use of severity assessment tools and the application of care bundles via clinical decision support tools. The bundles include early guideline-concordant antibiotics including macrolides, early haemodynamic support (lactate measurement, intravenous fluids, and vasopressors), and early respiratory support (high-flow nasal cannulae, lung-protective ventilation, prone positioning, and neuromuscular blockade for acute respiratory distress syndrome).While the proposed interventions appear straightforward, multiple barriers to their implementation exist. To successfully decrease mortality for severe CAP, early and close collaboration between emergency medicine and respiratory and critical care medicine teams is required. We propose a workflow incorporating these interventions. PMID:27567896

  3. Insights about serum sodium behavior after 24 hours of continuous renal replacement therapy

    PubMed Central

    Romano, Thiago Gomes; Martins, Cassia Pimenta Barufi; Mendes, Pedro Vitale; Besen, Bruno Adler Maccagnan Pinheiro; Zampieri, Fernando Godinho; Park, Marcelo

    2016-01-01

    Objective The aim of this study was to investigate the clinical and laboratorial factors associated with serum sodium variation during continuous renal replacement therapy and to assess whether the perfect admixture formula could predict 24-hour sodium variation. Methods Thirty-six continuous renal replacement therapy sessions of 33 patients, in which the affluent prescription was unchanged during the first 24 hours, were retrieved from a prospective collected database and then analyzed. A mixed linear model was performed to investigate the factors associated with large serum sodium variations (≥ 8mEq/L), and a Bland-Altman plot was generated to assess the agreement between the predicted and observed variations. Results In continuous renal replacement therapy 24-hour sessions, SAPS 3 (p = 0.022) and baseline hypernatremia (p = 0.023) were statistically significant predictors of serum sodium variations ≥ 8mEq/L in univariate analysis, but only hypernatremia demonstrated an independent association (β = 0.429, p < 0.001). The perfect admixture formula for sodium prediction at 24 hours demonstrated poor agreement with the observed values. Conclusions Hypernatremia at the time of continuous renal replacement therapy initiation is an important factor associated with clinically significant serum sodium variation. The use of 4% citrate or acid citrate dextrose - formula A 2.2% as anticoagulants was not associated with higher serum sodium variations. A mathematical prediction for the serum sodium concentration after 24 hours was not feasible. PMID:27410407

  4. Accuracy of children's school-breakfast reports and school-lunch reports (in 24-hour dietary recalls) differs by retention interval

    PubMed Central

    Baxter, Suzanne Domel; Guinn, Caroline H.; Royer, Julie A.; Hardin, James W.; Mackelprang, Alyssa J.; Smith, Albert F.

    2009-01-01

    Background/Objectives Validation-study data were analyzed to investigate the effect of retention interval (time between the to-be-reported meal and interview) on accuracy of children's school-breakfast reports and school-lunch reports in 24-hour recalls, and to compare accuracy of children's school-breakfast reports for two breakfast locations (classroom; cafeteria). Subjects/Methods Each of 374 fourth-grade children was interviewed to obtain a 24-hour recall using one of six conditions from crossing two target periods (prior 24 hours; previous day) with three interview times (morning; afternoon; evening). Each condition had 62 or 64 children (half boys). A recall's target period included one school breakfast and one school lunch, for which the child had been observed. Food-item variables (observed number; reported number; omission rate; intrusion rate) and energy variables (observed; reported; report rate; correspondence rate; inflation ratio) were calculated for each child for school breakfast and school lunch separately. Results Accuracy for school-breakfast reports and school-lunch reports was inversely related to retention interval. Specifically, as indicated by smaller omission rates, smaller intrusion rates, larger correspondence rates, and smaller inflation ratios, accuracy for school-breakfast reports was best for prior-24-hour recalls in the morning, and accuracy for school-lunch reports was best for prior-24-hour recalls in the afternoon. For neither school meal was a significant sex effect found for any variable. For school-breakfast reports, there was no significant school-breakfast location effect for any variable. Conclusions By shortening the retention interval, accuracy can be improved for school-breakfast reports and school-lunch reports in children's 24-hour recalls. PMID:19756033

  5. Heart Rate Variability – A Historical Perspective

    PubMed Central

    Billman, George E.

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R–R interval – the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration – the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the “Physician’s Pulse Watch” (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV. PMID:22144961

  6. Heart rate variability - a historical perspective.

    PubMed

    Billman, George E

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R-R interval - the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration - the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the "Physician's Pulse Watch" (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV. PMID:22144961

  7. Heart Rate, Life Expectancy and the Cardiovascular System: Therapeutic Considerations.

    PubMed

    Boudoulas, Konstantinos Dean; Borer, Jeffrey S; Boudoulas, Harisios

    2015-01-01

    It has long been known that life span is inversely related to resting heart rate in most organisms. This association between heart rate and survival has been attributed to the metabolic rate, which is greater in smaller animals and is directly associated with heart rate. Studies have shown that heart rate is related to survival in apparently healthy individuals and in patients with different underlying cardiovascular diseases. A decrease in heart rate due to therapeutic interventions may result in an increase in survival. However, there are many factors regulating heart rate, and it is quite plausible that these may independently affect life expectancy. Nonetheless, a fast heart rate itself affects the cardiovascular system in multiple ways (it increases ventricular work, myocardial oxygen consumption, endothelial stress, aortic/arterial stiffness, decreases myocardial oxygen supply, other) which, in turn, may affect survival. In this brief review, the effects of heart rate on the heart, arterial system and survival will be discussed.

  8. Agreement between 24-hour salt ingestion and sodium excretion in a controlled environment.

    PubMed

    Lerchl, Kathrin; Rakova, Natalia; Dahlmann, Anke; Rauh, Manfred; Goller, Ulrike; Basner, Mathias; Dinges, David F; Beck, Luis; Agureev, Alexander; Larina, Irina; Baranov, Victor; Morukov, Boris; Eckardt, Kai-Uwe; Vassilieva, Galina; Wabel, Peter; Vienken, Jörg; Kirsch, Karl; Johannes, Bernd; Krannich, Alexander; Luft, Friedrich C; Titze, Jens

    2015-10-01

    Accurately collected 24-hour urine collections are presumed to be valid for estimating salt intake in individuals. We performed 2 independent ultralong-term salt balance studies lasting 105 (4 men) and 205 (6 men) days in 10 men simulating a flight to Mars. We controlled dietary intake of all constituents for months at salt intakes of 12, 9, and 6 g/d and collected all urine. The subjects' daily menus consisted of 27 279 individual servings, of which 83.0% were completely consumed, 16.5% completely rejected, and 0.5% incompletely consumed. Urinary recovery of dietary salt was 92% of recorded intake, indicating long-term steady-state sodium balance in both studies. Even at fixed salt intake, 24-hour urine collection for sodium excretion (UNaV) showed infradian rhythmicity. We defined a ±25 mmol deviation from the average difference between recorded sodium intake and UNaV as the prediction interval to accurately classify a 3-g difference in salt intake. Because of the biological variability in UNaV, only every other daily urine sample correctly classified a 3-g difference in salt intake (49%). By increasing the observations to 3 consecutive 24-hour collections and sodium intakes, classification accuracy improved to 75%. Collecting seven 24-hour urines and sodium intake samples improved classification accuracy to 92%. We conclude that single 24-hour urine collections at intakes ranging from 6 to 12 g salt per day were not suitable to detect a 3-g difference in individual salt intake. Repeated measurements of 24-hour UNaV improve precision. This knowledge could be relevant to patient care and the conduct of intervention trials.

  9. Modeling heart rate variability by stochastic feedback

    NASA Technical Reports Server (NTRS)

    Amaral, L. A.; Goldberger, A. L.; Stanley, H. E.

    1999-01-01

    We consider the question of how the cardiac rhythm spontaneously self-regulates and propose a new mechanism as a possible answer. We model the neuroautonomic regulation of the heart rate as a stochastic feedback system and find that the model successfully accounts for key characteristics of cardiac variability, including the 1/f power spectrum, the functional form and scaling of the distribution of variations of the interbeat intervals, and the correlations in the Fourier phases which indicate nonlinear dynamics.

  10. Multiscale power analysis for heart rate variability

    NASA Astrophysics Data System (ADS)

    Zeng, Peng; Liu, Hongxing; Ni, Huangjing; Zhou, Jing; Xia, Lan; Ning, Xinbao

    2015-06-01

    We first introduce multiscale power (MSP) method to assess the power distribution of physiological signals on multiple time scales. Simulation on synthetic data and experiments on heart rate variability (HRV) are tested to support the approach. Results show that both physical and psychological changes influence power distribution significantly. A quantitative parameter, termed power difference (PD), is introduced to evaluate the degree of power distribution alteration. We find that dynamical correlation of HRV will be destroyed completely when PD>0.7.

  11. Phase asymmetry of heart rate variability signal.

    PubMed

    Karmakar, C K; Khandoker, A H; Palaniswami, M

    2015-02-01

    Heart rate asymmetry (HRA) is considered as a physiological phenomenon in healthy subjects. In this article, we propose a novel HRA index, Slope Index (SI), to quantify phase asymmetry of heart rate variability (HRV) system. We assessed the performance of proposed index in comparison with conventional (Guzik's Index (GI) and Porta's Index (PI)) HRA indices. As illustrative examples, we used two case studies: (i) differentiate physiologic RR series from synthetic RR series; and (ii) discriminate arrhythmia subjects from Healthy using beat-to-beat heart rate time series. The results showed that SI is a superior parameter than GI and PI for both case studies with maximum ROC area of 0.84 and 0.82 respectively. In contrast, GI and PI had ROC areas {0.78, 0.61} and {0.50, 0.56} in two case studies respectively. We also performed surrogate analysis to show that phase asymmetry is caused by a physiologic phenomena rather than a random nature of the signal. In conclusion, quantification of phase asymmetry of HRV provides additional information on HRA, which might have a potential clinical use to discriminate pathological HRV in future.

  12. Bluetooth Heart Rate Monitors for Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, R. E.; West, M. R.; Kalogera, K. L.; Hanson, A. M.

    2016-01-01

    Heart rate monitoring is required for crewmembers during exercise aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data are required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth heart rate monitors (BT HRM) and their ability to provide high quality heart rate data to monitor crew health aboard the ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) were worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT HRM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the 2 data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. RESULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6% error), followed by CS4 (3.3% error), CS3 (6.4% error), and CS2 (9.2% error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, but unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to obtain the best quality data. CS2 will be

  13. Bluetooth Heart Rate Monitors For Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, R. E.; West, M. R.; Kalogera, K. L.; Hanson, A. M.

    2016-01-01

    Heart rate monitoring is required for crewmembers during exercise aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data are required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health aboard the ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) were worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_HRM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the 2 data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. RESULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6% error), followed by CS4 (3.3% error), CS3 (6.4% error), and CS2 (9.2% error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, but unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to obtain the best quality data. CS2 will be

  14. Mood-Dependent Cognitive Change in a Man with Bipolar Disorder Who Cycles Every 24 Hours

    ERIC Educational Resources Information Center

    Lam, Dominic; Mansell, Warren

    2008-01-01

    A case study of a bipolar patient whose mood changes every 24 hours is described to illustrate the changes in cognitive processing and content during different phases of bipolar disorder. The participant completed a battery of questionnaires and tasks on 4 separate occasions: twice when depressed and twice when manic. Depression tended to be…

  15. Leg skinfold thicknesses and race performance in male 24-hour ultra-marathoners.

    PubMed

    Knechtle, Beat; Knechtle, Patrizia; Rüst, Christoph Alexander; Rosemann, Thomas

    2011-04-01

    The association of skinfold thicknesses with race performance has been investigated in runners competing over distances of ≤50 km. This study investigated a potential relation between skinfold thicknesses and race performance in male ultra-marathoners completing >50 km in 24 hours. Variables of anthropometry, training, and previous performance were related to race performance in 63 male ultra-marathoners aged 46.9 (standard deviation [SD] 10.3) years, standing 1.78 (SD 0.07) m in height, and weighing 73.3 (SD 7.6) kg. The runners clocked 146.1 (SD 43.1) km during the 24 hours. In the bivariate analysis, several variables were associated with race performance: body mass (r = -0.25); skinfold thickness at axilla (r = -0.37), subscapula (r = -0.28), abdomen (r = -0.31), and suprailiaca (r = -0.30); the sum of skinfold thicknesses (r = -0.32); percentage body fat (r = -0.32); weekly kilometers run (r = 0.31); personal best time in a marathon (r = -0.58); personal best time in a 100-km ultra-run (r = -0.31); and personal best performance in a 24-hour run (r = 0.46). In the multivariate analysis, no anthropometric or training variable was related to race performance. In conclusion, in contrast to runners up to distances of 50 km, skinfold thicknesses of the lower limbs were not related to race performance in 24-hour ultra-marathoners.

  16. The Three-Continent, 24-Hour Help Desk: An Academic First?

    ERIC Educational Resources Information Center

    Sykes, Jean

    2002-01-01

    Describes Follow the Sun, a computer help-desk service that takes advantage of time differences around the world to permit four universities (University of Colorado Boulder, Australia's Macquarie and Newcastle universities, and the London School of Economics) to share services and provide 24-hour support to users. (EV)

  17. Assessing dietary intake in childhood cancer survivors: Food frequency questionnaire versus 24-hour diet recalls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cancer diagnosis and treatment may influence dietary intake. The validity of using self-reported methods to quantify dietary intake has not been evaluated in childhood cancer survivors. We validated total energy intake (EI) reported from Food Frequency Questionnaire (FFQ) and repeated 24-hour diet r...

  18. Oropharyngeal 24-Hour pH Monitoring in Children With Airway-Related Problems

    PubMed Central

    Mesallam, Tamer A.

    2016-01-01

    Objectives Diagnosis and clinical presentation of pediatric laryngopharyngeal reflux (LPR) is still controversial. The aims of this work were to study the possibility of performing 24-hour oropharyngeal pH monitoring for children in the outpatient clinic setup and to explore the results of this test in correlation to airway-related problems. Methods In this descriptive qualitative study, 26 children suffering from airway-related problems were included. Oropharyngeal 24-hour pH monitoring was performed for all subjects in the outpatient clinic setting. The distribution of airway diagnoses among the study group was studied versus the results of the pH monitoring. Results There were 16 males and 10 females participated in the study with a mean age of 6.88 (SD, ±5.77) years. Thirty-five percent of the patients were under the age of 3 years (range, 11 months to 3 years). Eight-five percent of the patients tolerated the pH probe insertion and completed 24-hour of pH recording. Laryngomalacia and subglottic stenosis (SGS) were more frequently reported in the positive LPR patients (77%). Conclusion Oropharyngeal 24-hour pH monitoring can be conducted for children in the outpatient setup even in young age children below 3 years old. Among the positive LPR group, SGS and laryngomalacia were the most commonly reported airway findings. PMID:27090271

  19. Passive fetal heart rate monitoring apparatus and method with enhanced fetal heart beat discrimination

    NASA Technical Reports Server (NTRS)

    Zahorian, Stephen A. (Inventor); Livingston, David L. (Inventor); Pretlow, III, Robert A. (Inventor)

    1996-01-01

    An apparatus for acquiring signals emitted by a fetus, identifying fetal heart beats and determining a fetal heart rate. Multiple sensor signals are outputted by a passive fetal heart rate monitoring sensor. Multiple parallel nonlinear filters filter these multiple sensor signals to identify fetal heart beats in the signal data. A processor determines a fetal heart rate based on these identified fetal heart beats. The processor includes the use of a figure of merit weighting of heart rate estimates based on the identified heart beats from each filter for each signal. The fetal heart rate thus determined is outputted to a display, storage, or communications channel. A method for enhanced fetal heart beat discrimination includes acquiring signals from a fetus, identifying fetal heart beats from the signals by multiple parallel nonlinear filtering, and determining a fetal heart rate based on the identified fetal heart beats. A figure of merit operation in this method provides for weighting a plurality of fetal heart rate estimates based on the identified fetal heart beats and selecting the highest ranking fetal heart rate estimate.

  20. Measurement error corrected sodium and potassium intake estimation using 24-hour urinary excretion.

    PubMed

    Huang, Ying; Van Horn, Linda; Tinker, Lesley F; Neuhouser, Marian L; Carbone, Laura; Mossavar-Rahmani, Yasmin; Thomas, Fridtjof; Prentice, Ross L

    2014-02-01

    Epidemiological studies of the association of sodium and potassium intake with cardiovascular disease risk have almost exclusively relied on self-reported dietary data. Here, 24-hour urinary excretion assessments are used to correct the dietary self-report data for measurement error under the assumption that 24-hour urine recovery provides a biomarker that differs from usual intake according to a classical measurement model. Under this assumption, dietary self-reports underestimate sodium by 0% to 15%, overestimate potassium by 8% to 15%, and underestimate sodium/potassium ratio by ≈20% using food frequency questionnaires, 4-day food records, or three 24-hour dietary recalls in Women's Health Initiative studies. Calibration equations are developed by linear regression of log-transformed 24-hour urine assessments on corresponding log-transformed self-report assessments and several study subject characteristics. For each self-report method, the calibration equations turned out to depend on race and age and strongly on body mass index. After adjustment for temporal variation, calibration equations using food records or recalls explained 45% to 50% of the variation in (log-transformed) 24-hour urine assessments for sodium, 60% to 70% of the variation for potassium, and 55% to 60% of the variation for sodium/potassium ratio. These equations may be suitable for use in epidemiological disease association studies among postmenopausal women. The corresponding signals from food frequency questionnaire data were weak, but calibration equations for the ratios of sodium and potassium/total energy explained ≈35%, 50%, and 45% of log-biomarker variation for sodium, potassium, and their ratio, respectively, after the adjustment for temporal biomarker variation and may be suitable for cautious use in epidemiological studies. Clinical Trial Registration- URL: www.clinicaltrials.gov. Unique identifier: NCT00000611.

  1. The mitochondrial uniporter controls fight or flight heart rate increases.

    PubMed

    Wu, Yuejin; Rasmussen, Tyler P; Koval, Olha M; Joiner, Mei-Ling A; Hall, Duane D; Chen, Biyi; Luczak, Elizabeth D; Wang, Qiongling; Rokita, Adam G; Wehrens, Xander H T; Song, Long-Sheng; Anderson, Mark E

    2015-01-01

    Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant-negative (DN) MCU. Here, we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found that MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU-enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment before each heartbeat. Our findings show that MCU is necessary for complete physiological heart rate acceleration and suggest that MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate. PMID:25603276

  2. The mitochondrial uniporter controls fight or flight heart rate increases.

    PubMed

    Wu, Yuejin; Rasmussen, Tyler P; Koval, Olha M; Joiner, Mei-Ling A; Hall, Duane D; Chen, Biyi; Luczak, Elizabeth D; Wang, Qiongling; Rokita, Adam G; Wehrens, Xander H T; Song, Long-Sheng; Anderson, Mark E

    2015-01-20

    Heart rate increases are a fundamental adaptation to physiological stress, while inappropriate heart rate increases are resistant to current therapies. However, the metabolic mechanisms driving heart rate acceleration in cardiac pacemaker cells remain incompletely understood. The mitochondrial calcium uniporter (MCU) facilitates calcium entry into the mitochondrial matrix to stimulate metabolism. We developed mice with myocardial MCU inhibition by transgenic expression of a dominant-negative (DN) MCU. Here, we show that DN-MCU mice had normal resting heart rates but were incapable of physiological fight or flight heart rate acceleration. We found that MCU function was essential for rapidly increasing mitochondrial calcium in pacemaker cells and that MCU-enhanced oxidative phoshorylation was required to accelerate reloading of an intracellular calcium compartment before each heartbeat. Our findings show that MCU is necessary for complete physiological heart rate acceleration and suggest that MCU inhibition could reduce inappropriate heart rate increases without affecting resting heart rate.

  3. 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

  4. Metabolic and renal changes in two athletes during a world 24 hour relay record performance.

    PubMed Central

    Irving, R A; Noakes, T D; van Zyl Smit, R

    1989-01-01

    Metabolic parameters and renal function were studied in two subjects before, during and after they established a world two-man 24 hour relay record. During the race, the athletes expended an estimated 37.747 and 42.880 kJ running at 54 and 61 per cent of maximum oxygen consumption (VO2max). Rectal temperatures reached maxima of 38.6 and 39.2 degrees C respectively during the race. Serum free fatty acid levels peaked at 2108 and 1875 mumol ml-1 after 24 hours; blood glucose levels varied from 4.3-6.5 and 4.9-8.5 mmol.l-1 respectively. Plasma insulin levels fell from 42.9 and 22.7 microU.ml-1 to 11.5 microU.ml-1. Plasma urea, creatinine, beta 2-microglobulin and C-reactive protein concentrations were elevated at the end of the race (to 9.0 and 8.0 mmol.l-1, 119 and 102 mumol.l-1, 3.508 and 3203 micrograms.l-1 and 2.7 and 3.9 mg per cent respectively). Plasma osmolality was altered from 293 and 304 to 302 and 280 mosmol.Kg-1 during the race but increased to 312 and 318 mosmol.Kg-1 the following day probably due to intercompartmental fluid shifts. Plasma creatinine concentration was increased by 38 and 26 per cent due to reduced urinary excretion. Urine flow rate increased 40 and 123 per cent respectively during the race, but creatinine clearance decreased by 38 and 40 per cent. Urine osmolality decreased by 38 and 65 per cent and osmolal clearance decreased by 15 and 16 per cent respectively. Urine sodium excretion was greatly reduced (85 and 90 per cent) on the post-race days (by 88 and 92 per cent on day 2). Both urine total protein and beta2-microglobulin excretion increased during the race (by 89 and 35 per cent and by 334 and 136 per cent respectively), but owing to the increased beta2-microglobulin production renal clearance was unaltered. The changes in renal function were temporary and some aspects of renal tubular function were enhanced during the post-race days. We conclude that, although C-reactive protein concentrations increased sooner and were higher

  5. Acoustically based fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Baker, Donald A.; Zuckerwar, Allan J.

    1991-01-01

    The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which performs a linear prediction routine in real time. Clinical tests reveal that the acoustically based monitor provides Non-Stress Test records which are comparable to those obtained with a commercial ultrasonic transducer.

  6. Mental workload classification using heart rate metrics.

    PubMed

    Henelius, Andreas; Hirvonen, Kati; Holm, Anu; Korpela, Jussi; Muller, Kiti

    2009-01-01

    The ability of different short-term heart rate variability metrics to classify the level of mental workload (MWL) in 140 s segments was studied. Electrocardiographic data and event related potentials (ERPs), calculated from electroencephalographic data, were collected from 13 healthy subjects during the performance of a computerised cognitive multitask test with different task load levels. The amplitude of the P300 component of the ERPs was used as an objective measure of MWL. Receiver operating characteristics analysis (ROC) showed that the time domain metric of average interbeat interval length was the best-performing metric in terms of classification ability.

  7. Heart rate discrimination and heart rate control: a test of Brener's theory.

    PubMed

    Grigg, L; Ashton, R

    1984-12-01

    Three experiments were conducted to examine predictions from Brener's theory regarding the relationship between autonomic discrimination and autonomic control. Experiment 1 examined the possibility that training subjects to discriminate their heart rates would enhance their skill at controlling that response. Twenty subjects participated in two sessions during which one group of 10 subjects received training (knowledge of results) on the Ashton discrimination technique. The second group performed the discrimination task but received no training. All subjects then took part in a third session of heart rate (HR) control (both increase and decrease) where half of each of the aforementioned groups received feedback during the control task, while the other half performed the HR control task without feedback. Results indicated that for the control of both HR increases and decreases, there was no significant difference between those subjects trained to discriminate their HR, and those who had received no training to discriminate HR. The second experiment investigated the hypothesis that training subjects with feedback to control their HR would enhance their capacity to discriminate their heart activity. Ten subjects participated in two sessions of HR control during which half the subjects received feedback training to increase HR. During a third session, all subjects underwent a test of discrimination ability using the Ashton technique, and no knowledge of results regarding performance was provided. Results confirmed the hypothesis. The final experiment in the series investigated the discrimination/control relationship within a problem-solving framework and used 20 subjects. Results confirmed the hypothesis that subjects forewarned at the time of discrimination training that a heart rate control task was to follow would perform better than 10 subjects receiving no forewarning of the task objective. This effect took place independently of cardiac discrimination ability. A

  8. Model-based Heart rate prediction during Lokomat walking.

    PubMed

    Koenig, Alexander C; Somaini, Luca; Pulfer, Michael; Holenstein, Thomas; Omlin, Ximena; Wieser, Martin; Riener, Robert

    2009-01-01

    We implemented a model for prediction of heart rate during Lokomat walking. Using this model, we can predict potential overstressing of the patient and adapt the physical load accordingly. Current models for treadmill based heart rate control neglect the fact that the interaction torques between Lokomat and human can have a significant effect on heart rate. Tests with five healthy subjects lead to a model of sixth order with walking speed and power expenditure as inputs and heart rate prediction as output. Recordings with five different subjects were used for model validation. Future work includes model identification and predictive heart rate control with spinal cord injured and stroke patients. PMID:19963765

  9. The Forgotten Role of Central Volume in Low Frequency Oscillations of Heart Rate Variability

    PubMed Central

    Ferrario, Manuela; Moissl, Ulrich; Garzotto, Francesco; Cruz, Dinna N.; Tetta, Ciro; Signorini, Maria G.; Ronco, Claudio; Grassmann, Aileen; Cerutti, Sergio; Guzzetti, Stefano

    2015-01-01

    The hypothesis that central volume plays a key role in the source of low frequency (LF) oscillations of heart rate variability (HRV) was tested in a population of end stage renal disease patients undergoing conventional hemodialysis (HD) treatment, and thus subject to large fluid shifts and sympathetic activation. Fluid overload (FO) in 58 chronic HD patients was assessed by whole body bioimpedance measurements before the midweek HD session. Heart Rate Variability (HRV) was measured using 24-hour Holter electrocardiogram recordings starting before the same HD treatment. Time domain and frequency domain analyses were performed on HRV signals. Patients were retrospectively classified in three groups according to tertiles of FO normalized to the extracellular water (FO/ECW%). These groups were also compared after stratification by diabetes mellitus. Patients with the low to medium hydration status before the treatment (i.e. 1st and 2nd FO/ECW% tertiles) showed a significant increase in LF power during last 30 min of HD compared to dialysis begin, while no significant change in LF power was seen in the third group (i.e. those with high pre-treatment hydration values). In conclusion, several mechanisms can generate LF oscillations in the cardiovascular system, including baroreflex feedback loops and central oscillators. However, the current results emphasize the role played by the central volume in determining the power of LF oscillations. PMID:25793464

  10. [Identification of paroxysmal, transient arrhythmias: Intermittent registration more efficient than the 24-hour Holter monitoring].

    PubMed

    Hendrikx, Tijn; Rosenqvist, Mårten; Sandström, Herbert; Persson, Mats; Hörnsten, Rolf

    2015-01-06

    Many patients suffer from palpitations or dizziness/presyncope. These patients are often referred for Holter ECG (24 hour), although the sensitivity for detecting arrhythmias is low. A new method, short intermittent regular and symptomatic ECG registrations at home, might be a convenient and more sensitive alternative also suitable for primary health care. In this case report we present a patient who had contacted health care several times during a seven year period for paroxysmal palpitations. Routine examination with 24 hour Holter ECG and event recorder did not result in a diagnosis. Using intermittent handheld ECG registration at home, a paroxysmal supraventricular arrhythmia was diagnosed. Further investigation revealed that the patient had a concealed Wolff-Parkinson-White (WPW) syndrome.

  11. Pulmonary function in mechanically-ventilated patients during 24-hour use of a hygroscopic condensor humidifier.

    PubMed

    MacIntyre, N R; Anderson, H R; Silver, R M; Schuler, F R; Coleman, R E

    1983-11-01

    Hygroscopic condensor humidifiers (HCH) are reportedly capable of humidifying even the driest of ventilator source gases with at least 30 mg H2O/liter of ventilation. To assess the adequacy of the HCH during mechanical ventilation, we studied 26 patients over a 72-hour period (alternating 24-hour periods of humidification by a conventional cascade and the HCH). In these patients, we found no significant difference in static lung compliance, airway resistance, PaO2, and PaCO2 on either system. Additionally, estimates of sputum volume (over a four-hour collection period) and clearance of aerosolized 99mTc labelled DTPA (in five of these patients) also showed no significant differences between the two systems. We conclude that the HCH is capable of supplying necessary heat and moisture to most mechanically-ventilated patients for at least a period of 24 hours.

  12. Demonstration that thiazole-orange-positive platelets in the dog are less than 24 hours old.

    PubMed

    Dale, G L; Friese, P; Hynes, L A; Burstein, S A

    1995-04-01

    Approximately 6% of dog platelets are positive for staining with thiazole orange, a dye frequently used to stain ribonucleic acid. In this report, thiazole-orange positivity is shown to mark platelets that are less than 24 hours old. Dog platelets were derivatized in vivo with N-hydroxysuccinimido biotin such that greater than 95% of all platelets were biotinylated. Newly synthesized, nonbiotinylated platelets were then monitored by flow cytometry for their ability to bind thiazole orange. After biotinylation, the percentage of biotin-negative, thiazole-orange-positive platelets increased gradually from 0.72% at 30 minutes to 5.44% at 24 hours. These data indicate that thiazole-orange staining does label newly synthesized platelets.

  13. [Contraceptive effect of spermicide on cervical mucus in vivo after 24 hours (authors transl)].

    PubMed

    Batallan, L; Brissi, J; Commerot, J

    1980-10-01

    Efficacy of Alpagelle, a vaginal contraceptive jelly containing benzalkonium chlorohydrate, was tested on 34 women who had been using it for some. The testing was conducted using fresh human spermatozoa, and measuring the penetration into the cervical mucus 24 hours after instillation of 2 ml. of Alpagelle. Maximum penetration of spermatozoa before immobilization and death was 2/10 mm., while it is 2mm. a minute under normal conditions. Alpagelle has no contraindications, and only 1 application every 24 hours will provide contraceptive protection; such method could be ideal for women presenting temporary or permanent contraindications to the IUD, or to the pill, or to those who wish to opt for a method free of side effects. PMID:12262152

  14. Comparison of Interviewer-Administered and Automated Self-Administered 24-Hour Dietary Recalls in 3 Diverse Integrated Health Systems.

    PubMed

    Thompson, Frances E; Dixit-Joshi, Sujata; Potischman, Nancy; Dodd, Kevin W; Kirkpatrick, Sharon I; Kushi, Lawrence H; Alexander, Gwen L; Coleman, Laura A; Zimmerman, Thea P; Sundaram, Maria E; Clancy, Heather A; Groesbeck, Michelle; Douglass, Deirdre; George, Stephanie M; Schap, TusaRebecca E; Subar, Amy F

    2015-06-15

    Twenty-four-hour dietary recalls provide high-quality intake data but have been prohibitively expensive for large epidemiologic studies. This study's goal was to assess whether the web-based Automated Self-Administered 24-Hour Recall (ASA24) performs similarly enough to the standard interviewer-administered, Automated Multiple-Pass Method (AMPM) 24-hour dietary recall to be considered a viable alternative. In 2010-2011, 1,081 adults from 3 integrated health systems in Detroit, Michigan; Marshfield, Wisconsin; and Kaiser-Permanente Northern California participated in a field trial. A quota design ensured a diverse sample by sex, age, and race/ethnicity. Each participant was asked to complete 2 recalls and was randomly assigned to 1 of 4 protocols differing by type of recall and administration order. For energy, the mean intakes were 2,425 versus 2,374 kcal for men and 1,876 versus 1,906 kcal for women by AMPM and ASA24, respectively. Of 20 nutrients/food groups analyzed and controlling for false discovery rate, 87% were judged equivalent at the 20% bound. ASA24 was preferred over AMPM by 70% of the respondents. Attrition was lower in the ASA24/AMPM study group than in the AMPM/ASA24 group, and it was lower in the ASA24/ASA24 group than in the AMPM/AMPM group. ASA24 offers the potential to collect high-quality dietary intake information at low cost with less attrition.

  15. Circadian Polymorphisms in Night Owls, in Bipolars, and in Non-24-Hour Sleep Cycles

    PubMed Central

    Klimecki, Walter T.; Nievergelt, Caroline M.; Rex, Katharine M.; Murray, Sarah S.; Shekhtman, Tatyana; Tranah, Gregory J.; Loving, Richard T.; Lee, Heon-Jeong; Rhee, Min Kyu; Shadan, Farhad F.; Poceta, J. Steven; Jamil, Shazia M.; Kline, Lawrence E.; Kelsoe, John R.

    2014-01-01

    People called night owls habitually have late bedtimes and late times of arising, sometimes suffering a heritable circadian disturbance called delayed sleep phase syndrome (DSPS). Those with DSPS, those with more severe progressively-late non-24-hour sleep-wake cycles, and those with bipolar disorder may share genetic tendencies for slowed or delayed circadian cycles. We searched for polymorphisms associated with DSPS in a case-control study of DSPS research participants and a separate study of Sleep Center patients undergoing polysomnography. In 45 participants, we resequenced portions of 15 circadian genes to identify unknown polymorphisms that might be associated with DSPS, non-24-hour rhythms, or bipolar comorbidities. We then genotyped single nucleotide polymorphisms (SNPs) in both larger samples, using Illumina Golden Gate assays. Associations of SNPs with the DSPS phenotype and with the morningness-eveningness parametric phenotype were computed for both samples, then combined for meta-analyses. Delayed sleep and "eveningness" were inversely associated with loci in circadian genes NFIL3 (rs2482705) and RORC (rs3828057). A group of haplotypes overlapping BHLHE40 was associated with non-24-hour sleep-wake cycles, and less robustly, with delayed sleep and bipolar disorder (e.g., rs34883305, rs34870629, rs74439275, and rs3750275 were associated with n=37, p=4.58E-09, Bonferroni p=2.95E-06). Bright light and melatonin can palliate circadian disorders, and genetics may clarify the underlying circadian photoperiodic mechanisms. After further replication and identification of the causal polymorphisms, these findings may point to future treatments for DSPS, non-24-hour rhythms, and possibly bipolar disorder or depression. PMID:25395965

  16. Exercising in the Fasted State Reduced 24-Hour Energy Intake in Active Male Adults

    PubMed Central

    Deitrick, Ronald W.; Hillman, Angela R.

    2016-01-01

    The effect of fasting prior to morning exercise on 24-hour energy intake was examined using a randomized, counterbalanced design. Participants (12 active, white males, 20.8 ± 3.0 years old, VO2max: 59.1 ± 5.7 mL/kg/min) fasted (NoBK) or received breakfast (BK) and then ran for 60 minutes at 60%  VO2max. All food was weighed and measured for 24 hours. Measures of blood glucose and hunger were collected at 5 time points. Respiratory quotient (RQ) was measured during exercise. Generalized linear mixed models and paired sample t-tests examined differences between the conditions. Total 24-hour (BK: 19172 ± 4542 kJ versus NoBK: 15312 ± 4513 kJ; p < 0.001) and evening (BK: 12265 ± 4278 kJ versus NoBK: 10833 ± 4065; p = 0.039) energy intake and RQ (BK: 0.90 ± 0.03 versus NoBK: 0.86 ± 0.03; p < 0.001) were significantly higher in BK than NoBK. Blood glucose was significantly higher in BK than NoBK before exercise (5.2 ± 0.7 versus 4.5 ± 0.6 mmol/L; p = 0.025). Hunger was significantly lower for BK than NoBK before exercise, after exercise, and before lunch. Blood glucose and hunger were not associated with energy intake. Fasting before morning exercise decreased 24-hour energy intake and increased fat oxidation during exercise. Completing exercise in the morning in the fasted state may have implications for weight management. PMID:27738523

  17. Assessing variability of the 24-hour pad weight test in men with post-prostatectomy incontinence

    PubMed Central

    Malik, Rena D.; Cohn, Joshua A.; Fedunok, Pauline A.; Chung, Doreen E.; Bales, Gregory T.

    2016-01-01

    ABSTRACT Purpose: Decision-making regarding surgery for post-prostatectomy incontinence (PPI) is challenging. The 24-hour pad weight test is commonly used to objectively quantify PPI. However, pad weight may vary based upon activity level. We aimed to quantify variability in pad weights based upon patient-reported activity. Materials and Methods: 25 patients who underwent radical prostatectomy were prospectively enrolled. All patients demonstrated clinical stress urinary incontinence without clinical urgency urinary incontinence. On three consecutive alternating days, patients submitted 24-hour pad weights along with a short survey documenting activity level and number of pads used. Results: Pad weights collected across the three days were well correlated to the individual (ICC 0.85 (95% CI 0.74–0.93), p<0.001). The mean difference between the minimum pad weight leakage and maximum leakage per patient was 133.4g (95% CI 80.4–186.5). The mean increase in 24-hour leakage for a one-point increase in self-reported activity level was 118.0g (95% CI 74.3–161.7, p<0.001). Pad weights also varied significantly when self-reported activity levels did not differ (mean difference 51.2g (95% CI 30.3–72.1), p<0.001). Conclusions: 24-hour pad weight leakage may vary significantly on different days of collection. This variation is more pronounced with changes in activity level. Taking into account patient activity level may enhance the predictive value of pad weight testing. PMID:27256187

  18. Circadian polymorphisms in night owls, in bipolars, and in non-24-hour sleep cycles.

    PubMed

    Kripke, Daniel F; Klimecki, Walter T; Nievergelt, Caroline M; Rex, Katharine M; Murray, Sarah S; Shekhtman, Tatyana; Tranah, Gregory J; Loving, Richard T; Lee, Heon-Jeong; Rhee, Min Kyu; Shadan, Farhad F; Poceta, J Steven; Jamil, Shazia M; Kline, Lawrence E; Kelsoe, John R

    2014-10-01

    People called night owls habitually have late bedtimes and late times of arising, sometimes suffering a heritable circadian disturbance called delayed sleep phase syndrome (DSPS). Those with DSPS, those with more severe progressively-late non-24-hour sleep-wake cycles, and those with bipolar disorder may share genetic tendencies for slowed or delayed circadian cycles. We searched for polymorphisms associated with DSPS in a case-control study of DSPS research participants and a separate study of Sleep Center patients undergoing polysomnography. In 45 participants, we resequenced portions of 15 circadian genes to identify unknown polymorphisms that might be associated with DSPS, non-24-hour rhythms, or bipolar comorbidities. We then genotyped single nucleotide polymorphisms (SNPs) in both larger samples, using Illumina Golden Gate assays. Associations of SNPs with the DSPS phenotype and with the morningness-eveningness parametric phenotype were computed for both samples, then combined for meta-analyses. Delayed sleep and "eveningness" were inversely associated with loci in circadian genes NFIL3 (rs2482705) and RORC (rs3828057). A group of haplotypes overlapping BHLHE40 was associated with non-24-hour sleep-wake cycles, and less robustly, with delayed sleep and bipolar disorder (e.g., rs34883305, rs34870629, rs74439275, and rs3750275 were associated with n=37, p=4.58E-09, Bonferroni p=2.95E-06). Bright light and melatonin can palliate circadian disorders, and genetics may clarify the underlying circadian photoperiodic mechanisms. After further replication and identification of the causal polymorphisms, these findings may point to future treatments for DSPS, non-24-hour rhythms, and possibly bipolar disorder or depression. PMID:25395965

  19. Impedance and electrically evoked compound action potential (ECAP) drop within 24 hours after cochlear implantation.

    PubMed

    Chen, Joshua Kuang-Chao; Chuang, Ann Yi-Chiun; Sprinzl, Georg Mathias; Tung, Tao-Hsin; Li, Lieber Po-Hung

    2013-01-01

    Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI) insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP) variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implantation due to factors associated with wound conditions. The study presented our experiences with regards to initial switch-on within 24 hours, and thus the findings about the milieus inside cochlea within the first few hours after cochlear implantation in terms of impedance/ECAP fluctuations. The charts of fifty-four subjects with profound hearing impairment were studied. A minimal invasive approach was used for cochlear implantation, characterized by a small skin incision (≈ 2.5 cm) and soft techniques for cochleostomy. Impedance/ECAP was measured intro-operatively and within 24 hours post-operatively. Initial mapping within 24 hours post-operatively was performed in all patients without major complications. Impedance/ECAP became significantly lower measured within 24 hours post-operatively as compared with intra-operatively (p<0.001). There were no differences between pre-operative and post-operative threshold for air-conduction hearing. A significant drop of impedance/ECAP in one day after cochlear implantation was revealed for the first time in human beings. Mechanisms could be related to the restoration of neuronal sensitivity to the electrical stimulation, and/or the interaction between the matrix enveloping the electrodes and the electrical stimulation of the initial switch-on. Less wound pain/swelling and soft techniques both contributed to the success of immediate initial mapping, which implied a stable micro-environment inside the cochlea despite electrodes insertion. Our research invites further studies to correlate initial impedance/ECAP changes with long

  20. Impedance and Electrically Evoked Compound Action Potential (ECAP) Drop within 24 Hours after Cochlear Implantation

    PubMed Central

    Chen, Joshua Kuang-Chao; Chuang, Ann Yi-Chiun; Sprinzl, Georg Mathias; Tung, Tao-Hsin; Li, Lieber Po-Hung

    2013-01-01

    Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI) insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP) variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implantation due to factors associated with wound conditions. The study presented our experiences with regards to initial switch-on within 24 hours, and thus the findings about the milieus inside cochlea within the first few hours after cochlear implantation in terms of impedance/ECAP fluctuations. The charts of fifty-four subjects with profound hearing impairment were studied. A minimal invasive approach was used for cochlear implantation, characterized by a small skin incision (≈2.5 cm) and soft techniques for cochleostomy. Impedance/ECAP was measured intro-operatively and within 24 hours post-operatively. Initial mapping within 24 hours post-operatively was performed in all patients without major complications. Impedance/ECAP became significantly lower measured within 24 hours post-operatively as compared with intra-operatively (p<0.001). There were no differences between pre-operative and post-operative threshold for air-conduction hearing. A significant drop of impedance/ECAP in one day after cochlear implantation was revealed for the first time in human beings. Mechanisms could be related to the restoration of neuronal sensitivity to the electrical stimulation, and/or the interaction between the matrix enveloping the electrodes and the electrical stimulation of the initial switch-on. Less wound pain/swelling and soft techniques both contributed to the success of immediate initial mapping, which implied a stable micro-environment inside the cochlea despite electrodes insertion. Our research invites further studies to correlate initial impedance/ECAP changes with long

  1. Aerobic Fitness, Heart Rate Recovery and Heart Rate Recovery Time in Indian School Children.

    PubMed

    Fernando, Rajesh Jeniton; Ravichandran, K; Vaz, Mario

    2015-01-01

    Data on aerobic fitness and heart rate recovery in children are limited. This study was done to evaluate the relation between them in Indian school going children. Three hundred children of 7 to 10.5 years were recruited and their aerobic fitness was predicted using modified Harvard's step test (VO₂max) and 20 meter shuttle test (VO₂peak). The heart rate was monitored for 12 minutes post modified Harvard's step test. The difference between the maximum and the 1st minute HR was noted as HRR1 and the time taken to reach the resting heart rate was also recorded. VO₂max was inversely correlated with HRR1 (r = -0.64, p<0.001). However, the partial correlation of the two was not significant (r(partial) = -0.037, p = 0.55), indicating children with higher basal HR had higher HRR1 and that accounted for the observed association with aerobic fitness. Cox regression analysis showed that the recovery rate per unit time was 3% greater with increasing VO₂max (HR = 1.03, 95% CI:1.01 to 1.05, p = 0.013). The heart rate parameters did not show any associat with VO₂peak This study demonstrates that there is no relation between VO₂max and HRR1 after 3 minutes of modified Harvard's step test in Indian children of 7 to 10.5 years. However, aerobic fitness is a positive predictor of heart rate recovery time in this group. PMID:27530008

  2. 24-hour-restraint stress induces long-term depressive-like phenotypes in mice

    PubMed Central

    Zhou, Ying; Hu, Zhiqiang; Lou, Jingyu; Song, Wei; Li, Jing; Liang, Xiao; Chen, Chen; Wang, Shuai; Yang, Beimeng; Chen, Lei; Zhang, Xu; Song, Jinjing; Dong, Yujie; Chen, Shiqing; He, Lin; Xie, Qingguo; Chen, Xiaoping; Li, Weidong

    2016-01-01

    There is an increasing risk of mental disorders, such as acute stress disorder (ASD), post-traumatic stress disorder (PTSD) and depression among survivors who were trapped in rubble during earthquake. Such long-term impaction of a single acute restraint stress has not been extensively explored. In this study, we subjected mice to 24-hour-restraint to simulate the trapping episode, and investigated the acute (2 days after the restraint) and long-term (35 days after the restraint) impacts. Surprisingly, we found that the mice displayed depression-like behaviors, decreased glucose uptake in brain and reduced adult hippocampal neurogenesis 35 days after the restraint. Differential expression profiling based on microarrays suggested that genes and pathways related to depression and other mental disorders were differentially expressed in both PFC and hippocampus. Furthermore, the depression-like phenotypes induced by 24-hour-restraint could be reversed by fluoxetine, a type of antidepressant drug. These findings demonstrated that a single severe stressful event could produce long-term depressive-like phenotypes. Moreover, the 24-hour-restraint stress mice could also be used for further studies on mood disorders. PMID:27609090

  3. 24-hour-restraint stress induces long-term depressive-like phenotypes in mice

    NASA Astrophysics Data System (ADS)

    Chu, Xixia; Zhou, Ying; Hu, Zhiqiang; Lou, Jingyu; Song, Wei; Li, Jing; Liang, Xiao; Chen, Chen; Wang, Shuai; Yang, Beimeng; Chen, Lei; Zhang, Xu; Song, Jinjing; Dong, Yujie; Chen, Shiqing; He, Lin; Xie, Qingguo; Chen, Xiaoping; Li, Weidong

    2016-09-01

    There is an increasing risk of mental disorders, such as acute stress disorder (ASD), post-traumatic stress disorder (PTSD) and depression among survivors who were trapped in rubble during earthquake. Such long-term impaction of a single acute restraint stress has not been extensively explored. In this study, we subjected mice to 24-hour-restraint to simulate the trapping episode, and investigated the acute (2 days after the restraint) and long-term (35 days after the restraint) impacts. Surprisingly, we found that the mice displayed depression-like behaviors, decreased glucose uptake in brain and reduced adult hippocampal neurogenesis 35 days after the restraint. Differential expression profiling based on microarrays suggested that genes and pathways related to depression and other mental disorders were differentially expressed in both PFC and hippocampus. Furthermore, the depression-like phenotypes induced by 24-hour-restraint could be reversed by fluoxetine, a type of antidepressant drug. These findings demonstrated that a single severe stressful event could produce long-term depressive-like phenotypes. Moreover, the 24-hour-restraint stress mice could also be used for further studies on mood disorders.

  4. 24-hour-restraint stress induces long-term depressive-like phenotypes in mice.

    PubMed

    Chu, Xixia; Zhou, Ying; Hu, Zhiqiang; Lou, Jingyu; Song, Wei; Li, Jing; Liang, Xiao; Chen, Chen; Wang, Shuai; Yang, Beimeng; Chen, Lei; Zhang, Xu; Song, Jinjing; Dong, Yujie; Chen, Shiqing; He, Lin; Xie, Qingguo; Chen, Xiaoping; Li, Weidong

    2016-01-01

    There is an increasing risk of mental disorders, such as acute stress disorder (ASD), post-traumatic stress disorder (PTSD) and depression among survivors who were trapped in rubble during earthquake. Such long-term impaction of a single acute restraint stress has not been extensively explored. In this study, we subjected mice to 24-hour-restraint to simulate the trapping episode, and investigated the acute (2 days after the restraint) and long-term (35 days after the restraint) impacts. Surprisingly, we found that the mice displayed depression-like behaviors, decreased glucose uptake in brain and reduced adult hippocampal neurogenesis 35 days after the restraint. Differential expression profiling based on microarrays suggested that genes and pathways related to depression and other mental disorders were differentially expressed in both PFC and hippocampus. Furthermore, the depression-like phenotypes induced by 24-hour-restraint could be reversed by fluoxetine, a type of antidepressant drug. These findings demonstrated that a single severe stressful event could produce long-term depressive-like phenotypes. Moreover, the 24-hour-restraint stress mice could also be used for further studies on mood disorders. PMID:27609090

  5. Continuous 24-hour intraocular pressure monitoring for glaucoma--time for a paradigm change.

    PubMed

    Mansouri, K; Weinreb, R

    2012-01-01

    Glaucoma is the main cause of irreversible blindness and intraocular pressure (IOP) is its only modifiable risk factor. The importance of robust lowering of IOP for prevention of glaucoma onset and progression is well established. Although IOP is a dynamic parameter with individual circadian rhythms, current management usually relies on single IOP measurements during regular clinic hours performed a few times a year. Recent technological advances have provided clinicians with tools for continuous IOP monitoring during a 24 hour period in an ambulatory setting. There are two approaches being investigated. The first is permanent IOP monitoring through an implantable sensor and the other is temporary monitoring through a contact lens sensor. In this article, we discuss the shortcomings of the current gold standard for tonometry (Goldmann Applanation Tonometry) and the current experience with the first commercially available continuous 24 hour IOP monitoring technology (SENSIMED Triggerfish®); a telemetric contact lens sensor produced by a Swiss start-up company (Sensimed AG, Lausanne, Switzerland). Recent studies suggest that 24 hour continuous monitoring of IOP can be integrated into clinical practice and have the potential to contribute to the reduction of glaucoma-related vision loss.

  6. Relationship between ventricular ectopic beat frequency and heart rate: study in patients with severe arrhythmias.

    PubMed

    Acanfora, D; De Caprio, L; Di Palma, A; Furgi, G; Ing, F M; Migaux, M L; Rengo, F

    1993-04-01

    To evaluate and quantify the relationship between premature ventricular contractions (PVCs) and heart rate (HR), 57 patients (48 men and 8 women, mean age 59.8 +/- 7.9 years) with severe PVCs (Lown-Wolf grade > or = 3a) over 24 hours of Holter monitoring were studied. Twenty had no coronary artery disease (CAD), 25 had angiographically documented CAD, and 12 had acute myocardial infarction. All parameters of the 24-hour recordings from two ECG leads were measured by a Holter analyzer designed in our laboratory, based on fast microprocessors and controlled by a microcomputer. Scatter diagrams of the number of PVCs per minute as a function of HR and correlation coefficient were computed for various HR values corresponding to a total number of minutes greater than five. A positive correlation (r > or = 0.35) was found in most patients without CAD (85%); there was a complex relationship between the strength of the correlation and the presence of CAD or acute myocardial infarction because of a greater variability in the results of correlation coefficient analysis (coefficient of variation 62%, 208%, and 145% in patients without CAD, with CAD, and with acute myocardial infarction, respectively). The incidence of a positive correlation was similar in patients with Lown-Wolf grade III (63%), IVa (82%), or > or = IVb (67%) arrhythmias. The reproducibility of the correlation coefficient of the relationship between PVC frequency and HR was tested in 15 patients. The mean value of the correlation coefficient was 0.801 +/- 0.169 for the first test and 0.805 +/- 0.22 (p = NS) for the second test.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7682033

  7. Relationship between ventricular ectopic beat frequency and heart rate: study in patients with severe arrhythmias.

    PubMed

    Acanfora, D; De Caprio, L; Di Palma, A; Furgi, G; Ing, F M; Migaux, M L; Rengo, F

    1993-04-01

    To evaluate and quantify the relationship between premature ventricular contractions (PVCs) and heart rate (HR), 57 patients (48 men and 8 women, mean age 59.8 +/- 7.9 years) with severe PVCs (Lown-Wolf grade > or = 3a) over 24 hours of Holter monitoring were studied. Twenty had no coronary artery disease (CAD), 25 had angiographically documented CAD, and 12 had acute myocardial infarction. All parameters of the 24-hour recordings from two ECG leads were measured by a Holter analyzer designed in our laboratory, based on fast microprocessors and controlled by a microcomputer. Scatter diagrams of the number of PVCs per minute as a function of HR and correlation coefficient were computed for various HR values corresponding to a total number of minutes greater than five. A positive correlation (r > or = 0.35) was found in most patients without CAD (85%); there was a complex relationship between the strength of the correlation and the presence of CAD or acute myocardial infarction because of a greater variability in the results of correlation coefficient analysis (coefficient of variation 62%, 208%, and 145% in patients without CAD, with CAD, and with acute myocardial infarction, respectively). The incidence of a positive correlation was similar in patients with Lown-Wolf grade III (63%), IVa (82%), or > or = IVb (67%) arrhythmias. The reproducibility of the correlation coefficient of the relationship between PVC frequency and HR was tested in 15 patients. The mean value of the correlation coefficient was 0.801 +/- 0.169 for the first test and 0.805 +/- 0.22 (p = NS) for the second test.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Children's Heart Rate Reactivity Responses to Three School Tasks.

    ERIC Educational Resources Information Center

    Sharpley, Christopher F.; And Others

    1989-01-01

    Investigated effects of 3 routine classroom arithmetic and reading tasks upon the heart rate reactivity of 30 fifth grade children. Results indicated that some children showed large increases in heart rates during the three tasks, and that these children should be considered at risk for coronary heart disease. (Author/TE)

  9. Factors Associated With High Sodium Intake Based on Estimated 24-Hour Urinary Sodium Excretion

    PubMed Central

    Hong, Jae Won; Noh, Jung Hyun; Kim, Dong-Jun

    2016-01-01

    Abstract Although reducing dietary salt consumption is the most cost-effective strategy for preventing progression of cardiovascular and renal disease, policy-based approaches to monitor sodium intake accurately and the understanding factors associated with excessive sodium intake for the improvement of public health are lacking. We investigated factors associated with high sodium intake based on the estimated 24-hour urinary sodium excretion, using data from the 2009 to 2011 Korea National Health and Nutrition Examination Survey (KNHANES). Among 21,199 adults (≥19 years of age) who participated in the 2009 to 2011 KNHANES, 18,000 participants (weighted n = 33,969,783) who completed urinary sodium and creatinine evaluations were analyzed in this study. The 24-hour urinary sodium excretion was estimated using Tanaka equation. The mean estimated 24-hour urinary sodium excretion level was 4349 (4286–4413) mg per day. Only 18.5% (weighted n = 6,298,481/3,396,973, unweighted n = 2898/18,000) of the study participants consumed less the 2000 mg sodium per day. Female gender (P < 0.001), older age (P < 0.001), total energy intake ≥50 percentile (P < 0.005), and obesity (P < 0.001) were associated with high sodium intake, even after adjusting for potential confounders. Senior high school/college graduation in education and managers/professionals in occupation were associated with lower sodium intake (P < 0.001). According to hypertension management status, those who had hypertension without medication consumed more sodium than those who were normotensive. However, those who receiving treatment for hypertension consumed less sodium than those who were normotensive (P < 0.001). The number of family members, household income, and alcohol drinking did not affect 24-hour urinary sodium excretion. The logistic regression analysis for the highest estimated 24-hour urinary sodium excretion quartile (>6033 mg/day) using the

  10. Validation of triple pass 24-hour dietary recall in Ugandan children by simultaneous weighed food assessment

    PubMed Central

    Olupot-Olupot, Peter; Engoru, Charles; Ssenyondo, Tonny; Nteziyaremye, Julius; Amorut, Denis; Nakuya, Margaret; Arimi, Margaret; Frost, Gary; Maitland, Kathryn

    2016-01-01

    Background Undernutrition remains highly prevalent in African children, highlighting the need for accurately assessing dietary intake. In order to do so, the assessment method must be validated in the target population. A triple pass 24 hour dietary recall with volumetric portion size estimation has been described but not previously validated in African children. This study aimed to establish the relative validity of 24-hour dietary recalls of daily food consumption in healthy African children living in Mbale and Soroti, eastern Uganda compared to simultaneous weighed food records. Methods Quantitative assessment of daily food consumption by weighed food records followed by two independent assessments using triple pass 24-hour dietary recall on the following day. In conjunction with household measures and standard food sizes, volumes of liquid, dry rice, or play dough were used to aid portion size estimation. Inter-assessor agreement, and agreement with weighed food records was conducted primarily by Bland-Altman analysis and secondly by intraclass correlation coefficients and quartile cross-classification. Results 19 healthy children aged 6 months to 12 years were included in the study. Bland-Altman analysis showed 24-hour recall only marginally under-estimated energy (mean difference of 149kJ or 2.8%; limits of agreement -1618 to 1321kJ), protein (2.9g or 9.4%; -12.6 to 6.7g), and iron (0.43mg or 8.3%; -3.1 to 2.3mg). Quartile cross-classification was correct in 79% of cases for energy intake, and 89% for both protein and iron. The intraclass correlation coefficient between the separate dietary recalls for energy was 0.801 (95% CI, 0.429-0.933), indicating acceptable inter-observer agreement. Conclusions Dietary assessment using 24-hour dietary recall with volumetric portion size estimation resulted in similar and acceptable estimates of dietary intake compared with weighed food records and thus is considered a valid method for daily dietary intake assessment of

  11. Static stretching can impair explosive performance for at least 24 hours.

    PubMed

    Haddad, Monoem; Dridi, Amir; Chtara, Moktar; Chaouachi, Anis; Wong, Del P; Behm, David; Chamari, Karim

    2014-01-01

    The aim of this study was to compare the effects of static vs. dynamic stretching (DS) on explosive performances and repeated sprint ability (RSA) after a 24-hour delay. Sixteen young male soccer players performed 15 minutes of static stretching (SS), DS, or a no-stretch control condition (CC) 24 hours before performing explosive performances and RSA tests. This was a within-subject repeated measures study with SS, DS, and CC being counterbalanced. Stretching protocols included 2 sets of 7 minutes 30 seconds (2 repetitions of 30 seconds with a 15-second passive recovery) for 5 muscle groups (quadriceps, hamstring, calves, adductors, and hip flexors). Twenty-four hours later (without any kind of stretching in warm-up), the players were tested for the 30-m sprint test (with 10- and 20-m lap times), 5 jump test (5JT), and RSA test. Significant differences were observed between CC, SS, and DS with 5JT (F = 9.99, p < 0.00, effect size [ES] = 0.40), 10-m sprint time (F = 46.52, p < 0.00, ES = 0.76), 20-m sprint time (F = 18.44, p < 0.000, ES = 0.55), and 30-m sprint time (F = 34.25, p < 0.000, ES = 0.70). The significantly better performance (p < 0.05) was observed after DS as compared with that after CC and SS in 5JT, and sprint times for 10, 20, and 30 m. In contrast, significantly worse performance (p < 0.05) was observed after SS as compared with that after CC in 5JT, and sprint times for 10, 20, and 30 m. With RSA, no significant difference was observed between different stretching protocols in the total time (F = 1.55, p > 0.05), average time (F = 1.53, p > 0.05), and fastest time (F = 2.30, p > 0.05), except for the decline index (F = 3.54, p < 0.04, ES = 0.19). Therefore, the SS of the lower limbs and hip muscles had a negative effect on explosive performances up to 24 hours poststretching with no major effects on the RSA. Conversely, the DS of the same muscle groups are highly recommended 24 hours before performing sprint and long-jump performances. In

  12. Quantitative analysis of heart rate variability

    NASA Astrophysics Data System (ADS)

    Kurths, J.; Voss, A.; Saparin, P.; Witt, A.; Kleiner, H. J.; Wessel, N.

    1995-03-01

    In the modern industrialized countries every year several hundred thousands of people die due to sudden cardiac death. The individual risk for this sudden cardiac death cannot be defined precisely by common available, noninvasive diagnostic tools like Holter monitoring, highly amplified ECG and traditional linear analysis of heart rate variability (HRV). Therefore, we apply some rather unconventional methods of nonlinear dynamics to analyze the HRV. Especially, some complexity measures that are based on symbolic dynamics as well as a new measure, the renormalized entropy, detect some abnormalities in the HRV of several patients who have been classified in the low risk group by traditional methods. A combination of these complexity measures with the parameters in the frequency domain seems to be a promising way to get a more precise definition of the individual risk. These findings have to be validated by a representative number of patients.

  13. Entropy information of heart rate variability and its power spectrum during day and night

    NASA Astrophysics Data System (ADS)

    Jin, Li; Jun, Wang

    2013-07-01

    Physiologic systems generate complex fluctuations in their output signals that reflect the underlying dynamics. We employed the base-scale entropy method and the power spectral analysis to study the 24 hours heart rate variability (HRV) signals. The results show that such profound circadian-, age- and pathologic-dependent changes are accompanied by changes in base-scale entropy and power spectral distribution. Moreover, the base-scale entropy changes reflect the corresponding changes in the autonomic nerve outflow. With the suppression of the vagal tone and dominance of the sympathetic tone in congestive heart failure (CHF) subjects, there is more variability in the date fluctuation mode. So the higher base-scale entropy belongs to CHF subjects. With the decrease of the sympathetic tone and the respiratory frequency (RSA) becoming more pronounced with slower breathing during sleeping, the base-scale entropy drops in CHF subjects. The HRV series of the two healthy groups have the same diurnal/nocturnal trend as the CHF series. The fluctuation dynamics trend of data in the three groups can be described as “HF effect”.

  14. Bath water contamination with Legionella and nontuberculous mycobacteria in 24-hour home baths, hot springs, and public bathhouses of Nagano Prefecture, Japan.

    PubMed

    Kobayashi, Michiko; Oana, Kozue; Kawakami, Yoshiyuki

    2014-01-01

    Bath water samples were collected from 116 hot springs, 197 public bathhouses, and 38 24-hour home baths in Nagano Prefecture, Japan, during the period of April 2009 to November 2011, for determining the presence and extent of contamination with Legionella and nontuberculous mycobacteria. Cultures positive for Legionella were observed in 123 of the 3,314 bath water samples examined. The distribution and abundance of Legionella and/or combined contamination with Legionella and nontuberculous mycobacteria were investigated to clarify the contamination levels. The abundance of Legionella was demonstrated to correlate considerably with the levels of combined contamination with Legionella and nontuberculous mycobacteria. Legionella spp. were obtained from 61% of the water samples from 24-hour home baths, but only from 3% of the samples from public bathhouses and hot springs. This is despite the fact that a few outbreaks of Legionnaires' disease in Nagano Prefecture as well as other regions of Japan have been traced to bath water contamination. The comparatively higher rate of contamination of the 24-hour home baths is a matter of concern. It is therefore advisable to routinely implement good maintenance of the water basins, particularly of the 24-hour home baths.

  15. Ordinal pattern statistics for the assessment of heart rate variability

    NASA Astrophysics Data System (ADS)

    Graff, G.; Graff, B.; Kaczkowska, A.; Makowiec, D.; Amigó, J. M.; Piskorski, J.; Narkiewicz, K.; Guzik, P.

    2013-06-01

    The recognition of all main features of a healthy heart rhythm (the so-called sinus rhythm) is still one of the biggest challenges in contemporary cardiology. Recently the interesting physiological phenomenon of heart rate asymmetry has been observed. This phenomenon is related to unbalanced contributions of heart rate decelerations and accelerations to heart rate variability. In this paper we apply methods based on the concept of ordinal pattern to the analysis of electrocardiograms (inter-peak intervals) of healthy subjects in the supine position. This way we observe new regularities of the heart rhythm related to the distribution of ordinal patterns of lengths 3 and 4.

  16. Inverse Correlation between Heart Rate Variability and Heart Rate Demonstrated by Linear and Nonlinear Analysis

    PubMed Central

    Zhang, Henggui; Aziz, Wajid; Monfredi, Oliver; Abbas, Syed Ali; Shah, Saeed Arif; Kazmi, Syeda Sobia Hassan; Butt, Wasi Haider

    2016-01-01

    The dynamical fluctuations in the rhythms of biological systems provide valuable information about the underlying functioning of these systems. During the past few decades analysis of cardiac function based on the heart rate variability (HRV; variation in R wave to R wave intervals) has attracted great attention, resulting in more than 17000-publications (PubMed list). However, it is still controversial about the underling mechanisms of HRV. In this study, we performed both linear (time domain and frequency domain) and nonlinear analysis of HRV data acquired from humans and animals to identify the relationship between HRV and heart rate (HR). The HRV data consists of the following groups: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44); (c) rabbit sinoatrial node cells (SANC; n = 67); (d) conscious rat (n = 11). In both human and animal data at variant pathological conditions, both linear and nonlinear analysis techniques showed an inverse correlation between HRV and HR, supporting the concept that HRV is dependent on HR, and therefore, HRV cannot be used in an ordinary manner to analyse autonomic nerve activity of a heart. PMID:27336907

  17. Inverse Correlation between Heart Rate Variability and Heart Rate Demonstrated by Linear and Nonlinear Analysis.

    PubMed

    Kazmi, Syed Zaki Hassan; Zhang, Henggui; Aziz, Wajid; Monfredi, Oliver; Abbas, Syed Ali; Shah, Saeed Arif; Kazmi, Syeda Sobia Hassan; Butt, Wasi Haider

    2016-01-01

    The dynamical fluctuations in the rhythms of biological systems provide valuable information about the underlying functioning of these systems. During the past few decades analysis of cardiac function based on the heart rate variability (HRV; variation in R wave to R wave intervals) has attracted great attention, resulting in more than 17000-publications (PubMed list). However, it is still controversial about the underling mechanisms of HRV. In this study, we performed both linear (time domain and frequency domain) and nonlinear analysis of HRV data acquired from humans and animals to identify the relationship between HRV and heart rate (HR). The HRV data consists of the following groups: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44); (c) rabbit sinoatrial node cells (SANC; n = 67); (d) conscious rat (n = 11). In both human and animal data at variant pathological conditions, both linear and nonlinear analysis techniques showed an inverse correlation between HRV and HR, supporting the concept that HRV is dependent on HR, and therefore, HRV cannot be used in an ordinary manner to analyse autonomic nerve activity of a heart. PMID:27336907

  18. Twenty-four-Hour Ambulatory Blood Pressure Monitor Heart Rate: A Potential Marker for Gestational Hypertension in at-Risk Women

    PubMed Central

    Booker, Corenthian J.; Dodson, William C.; Kunselman, Allen R.; Repke, John T.; Legro, Richard S.

    2013-01-01

    We prospectively correlated the 24-hour ambulatory blood pressure measurements (ABPM) to conventional sphygmomanometer blood pressure measurements (CSM) in women at risk for gestational hypertensive disorders (GHTNDs) and identified predictive factors from ABPM for GHTND. We analyzed 73 women with ≥1 risk factor for developing a GHTND. Using both the CSM and ABPM, the systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), and heart rate (HR) were measured for 24 hours during three periods (14 to 24 weeks; 24 to 32 weeks; and 33 weeks to delivery). Correlation between the CSM and ABPM lessened as pregnancy progressed. Seventeen (25%) of women developed a GHTND. MAP variability increased in the GHTND group versus those without a GHTND. The odds of developing a GHTND increased 1.5 times for every 1 beat per minute increase in the ABPM 24-hour HR at visit 1 and reversed by visit 3. In women at risk for a GHTND, CSM and ABPM correlate less well as pregnancy advances. HR changes in at-risk women may be a marker for the development of a GHTND and may reflect increased sympathetic activity and/or decreased baroreceptor sensitivity. PMID:22147639

  19. Allometric estimation of metabolic rate from heart rate in penguins.

    PubMed

    Green, J A; White, C R; Butler, P J

    2005-12-01

    Studies of the relationship between heart rate (f(H)) and rate of oxygen consumption (V(.) (O(2))), which are then used to predict field metabolic rate, frequently fail to incorporate body mass as a predictive variable. This is a potentially important omission in the study of animals whose body mass fluctuates substantially during their annual cycle. In an attempt further to improve estimates of field metabolic rate from f(H), we re-evaluated data on M(b), f(H) and V(.) (O(2)) from previous studies of macaroni penguins (Eudyptes chrysolophus) and king penguins (Aptenodytes patagonicus) and derived a new relationship to integrate these three quantities. This relationship is at least as accurate and precise as previously determined relationships. We applied this same principle to published data on 11 of the 20 recognised penguin taxa to derive a relationship to predict V(.) (O(2)) from f(H) and M(b) in penguins of any species. This result has interesting implications in terms of reducing the logistical burden in studies of field metabolic rate. PMID:16297646

  20. Influence of Overweight on 24-Hour Urine Chemistry Studies and Recurrent Urolithiasis in Children

    PubMed Central

    Chung, Jae Dong; Kim, Tae-Hyoung; Myung, Soon Chul; Moon, Young Tae; Kim, Kyung Do

    2012-01-01

    Purpose We investigated the influence of overweight on 24-hour urine chemistry studies and recurrent urolithiasis (UL) in children. Materials and Methods A retrospective cohort study was designed to assess children who presented with UL at a pediatric institution between 1985 and 2010. We calculated body mass index percentile (BMIp) adjusted for gender and age according to the 2007 Korean Children and Adolescents Growth Chart and stratified the children into 3 BMI categories: lower body weight (LBW, BMIp≤10), normal BW (NBW, 1024-hour urine chemistry studies did not differ significantly between the three groups. Mean urine citrate levels were lower (0.273±0.218 mg/mg/d vs. 0.429±0.299 mg/mg/d, p<0.05) and the incidence of hypocitraturia was higher (81.5% vs. 45.7%, p<0.05)) in the recurrent stone former group. In the univariate analysis, hypocitraturia and acidic urinary pH were risk factors, but in the multivariate analysis, only hypocitraturia was a risk factor for stone recurrence (hazard ratio, 3.647; 95% confidence interval, 1.047 to 12.703). In the Kaplan-Meier curve, the hypocitraturia group showed higher recurrence than did the normocitraturia group (p<0.05). Conclusions Unlike in adults, in children, overweight adjusted for gender and age was not associated with 24-hour urine chemistry studies and was not a risk factor for recurrent UL. Hypocitraturia was the only risk factor for UL in children. PMID:22536471

  1. Treating allergic conjunctivitis: A once-daily medication that provides 24-hour symptom relief

    PubMed Central

    Schaeffer, Jack; Donnenfeld, Eric

    2016-01-01

    Background: Allergic conjunctivitis (AC) is a common ocular inflammatory manifestation of allergen exposure in sensitized individuals. Signs and symptoms of AC can decrease quality of life, interfere with productivity, and lead to considerable economic burden. Consistent suppression of conjunctival inflammation is necessary for managing AC, but currently available medications require frequent administration and exhibit limited duration of action. Methods: In this review, we summarized AC pathogenesis, diagnosis, and current treatment options as well as their limitations. Findings from the literature were discussed in the context of the unmet need for a once-daily medication with sustained 24-hour effectiveness. Results: Topical pharmacologic treatments are the most common approach for managing extant AC; however, most available medications require multiple daily instillations. Dual-acting antihistamine-mast cell stabilizing agents are currently considered first-line therapeutics for AC because they provide acute relief of signs and symptoms and block persistent inflammation to promote regression of AC. Recent studies of a newly-developed, higher-concentration formulation of a dual-acting antihistamine-mast cell stabilizer have demonstrated that this formulation provides a 24-hour duration of action with once-daily dosing. Conclusions: Dual-acting AC medications exhibit a high degree of overall effectiveness and are well tolerated for chronic use. A newly available once-daily medication that manages signs and symptoms of AC for a full 24 hours may be considered a treatment of choice for patients experiencing seasonal or perennial AC. ClinicalTrials.gov NCT01743027 and NCT01479374 PMID:27466061

  2. 77 FR 65310 - Additional Air Quality Designations for the 2006 24-Hour Fine Particle National Ambient Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... the 2006 24-hour Fine Particle (PM 2.5 ) National Ambient Air Quality Standards,'' 74 FR 58688... Federal Regulations DC District of Columbia EO Executive Order EPA Environmental Protection Agency FR... EPA finalized designations for the 2006 24-hour PM 2.5 NAAQS (74 FR 58688, November 13, 2009), the...

  3. Assessing Dietary Intake in Childhood Cancer Survivors: Food Frequency Questionnaire Versus 24-Hour Diet Recalls.

    PubMed

    Zhang, Fang Fang; Roberts, Susan B; Must, Aviva; Wong, William W; Gilhooly, Cheryl H; Kelly, Michael J; Parsons, Susan K; Saltzman, Edward

    2015-10-01

    Cancer diagnosis and treatment may influence dietary intake. The validity of using self-reported methods to quantify dietary intake has not been evaluated in childhood cancer survivors. We validated total energy intake (EI) reported from Food Frequency Questionnaire (FFQ) and repeated 24-hour diet recalls (24HRs) against total energy expenditure (TEE) measured using the doubly labeled water method in 16 childhood cancer survivors. Dietary underreporting, assessed by (EI-TEE)/TEE × 100%, was 22% for FFQ and 1% for repeated 24HRs. FFQ significantly underestimates dietary intake and should not be used to assess the absolute intake of foods and nutrients in childhood cancer survivors.

  4. Intermittent short ECG recording is more effective than 24-hour Holter ECG in detection of arrhythmias

    PubMed Central

    2014-01-01

    Background Many patients report symptoms of palpitations or dizziness/presyncope. These patients are often referred for 24-hour Holter ECG, although the sensitivity for detecting relevant arrhythmias is comparatively low. Intermittent short ECG recording over a longer time period might be a convenient and more sensitive alternative. The objective of this study is to compare the efficacy of 24-hour Holter ECG with intermittent short ECG recording over four weeks to detect relevant arrhythmias in patients with palpitations or dizziness/presyncope. Methods Design: prospective, observational, cross-sectional study. Setting: Clinical Physiology, University Hospital. Patients: 108 consecutive patients referred for ambiguous palpitations or dizziness/presyncope. Interventions: All individuals underwent a 24-hour Holter ECG and additionally registered 30-second handheld ECG (Zenicor EKG® thumb) recordings at home, twice daily and when having cardiac symptoms, during 28 days. Main outcome measures: Significant arrhythmias: atrial fibrillation (AF), paroxysmal supraventricular tachycardia (PSVT), atrioventricular (AV) block II–III, sinus arrest (SA), wide complex tachycardia (WCT). Results 95 patients, 42 men and 53 women with a mean age of 54.1 years, completed registrations. Analysis of Holter registrations showed atrial fibrillation (AF) in two patients and atrioventricular (AV) block II in one patient (= 3.2% relevant arrhythmias [95% CI 1.1–8.9]). Intermittent handheld ECG detected nine patients with AF, three with paroxysmal supraventricular tachycardia (PSVT) and one with AV-block-II (= 13.7% relevant arrhythmias [95% CI 8.2–22.0]). There was a significant difference between the two methods in favour of intermittent ECG with regard to the ability to detect relevant arrhythmias (P = 0.0094). With Holter ECG, no symptoms were registered during any of the detected arrhythmias. With intermittent ECG, symptoms were registered during half of the arrhythmia

  5. Assessing Dietary Intake in Childhood Cancer Survivors: Food Frequency Questionnaire versus 24-Hour Diet Recalls

    PubMed Central

    Zhang, Fang Fang; Roberts, Susan B.; Must, Aviva; Wong, William W.; Gilhooly, Cheryl H.; Kelly, Michael J.; Parsons, lkSusan K.; Saltzman, Edward

    2015-01-01

    Cancer diagnosis and treatment may influence dietary intake. The validity of using self-reported methods to quantify dietary intake has not been evaluated in childhood cancer survivors. We validated total energy intake (EI) reported from food frequency questionnaire (FFQ) and repeated 24-hour diet recalls (24HRs) against total energy expenditure (TEE) measured using the doubly labeled water method in 16 childhood cancer survivors. Dietary underreporting, assessed by (EI-TEE)/TEE ×100%, was 22% for FFQ and 1% for repeated 24HRs. FFQ significantly underestimates dietary intake and should not be used to assess the absolute intake of foods and nutrients in childhood cancer survivors. PMID:25883059

  6. Interaction of a commercial heart rate monitor with implanted pacemakers.

    PubMed

    Joglar, J A; Hamdan, M H; Welch, P J; Page, R L

    1999-03-01

    Dry-electrode heart rate monitors allow display of heart rate by transmitting a signal to the receiving device, which typically is on the wrist or exercise machine, but due to the potential for electromagnetic interference, their use has been contraindicated in patients with pacemakers. In 12 patients, we found no adverse effect on pacemaker function; in addition, the monitors generally were accurate in measuring heart rate during pacing.

  7. Unconstrained Evaluation System for Heart Rate Using Ultrasonic Vibrograph

    NASA Astrophysics Data System (ADS)

    Nagamune, Kouki; Kobashi, Syoji; Kondo, Katsuya; Hata, Yutaka; Taniguchi, Kazuhiko; Sawayama, Toshiyuki

    2004-05-01

    Unconstrained health monitoring systems have received much considerable attention in medical applications, because such system can examine a subject without constraint. In this study, we propose a detection method based on a fuzzy logic for evaluating heart rate using our ultrasonic vibrograph. In the experiment for confirming heart rate, our method has been successfully used to detect the heart rates of four subjects, compared with a method using an electrocardiograph.

  8. Controlling the emotional heart: heart rate biofeedback improves cardiac control during emotional reactions.

    PubMed

    Peira, Nathalie; Fredrikson, Mats; Pourtois, Gilles

    2014-03-01

    When regulating negative emotional reactions, one goal is to reduce physiological reactions. However, not all regulation strategies succeed in doing that. We tested whether heart rate biofeedback helped participants reduce physiological reactions in response to negative and neutral pictures. When viewing neutral pictures, participants could regulate their heart rate whether the heart rate feedback was real or not. In contrast, when viewing negative pictures, participants could regulate heart rate only when feedback was real. Ratings of task success paralleled heart rate. Participants' general level of anxiety, emotion awareness, or cognitive emotion regulation strategies did not influence the results. Our findings show that accurate online heart rate biofeedback provides an efficient way to down-regulate autonomic physiological reactions when encountering negative stimuli. PMID:24373886

  9. A Bayesian classification of heart rate variability data

    NASA Astrophysics Data System (ADS)

    Muirhead, R. J.; Puff, R. D.

    2004-05-01

    We propose a simple Bayesian method for the classification of time series signals originating from mutually exclusive sources. In particular, the method is used to address the question of whether a 24-h recording of human heart rate data is produced by a normally functioning heart or by one exhibiting symptoms of congestive heart failure. Our method correctly classifies 18 of 18 normal heart data sets, and 38 of 44 congestive failure data sets.

  10. Critical Scale Invariance in a Healthy Human Heart Rate

    NASA Astrophysics Data System (ADS)

    Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Sakata, Seiichiro; Hayano, Junichiro; Yamamoto, Yoshiharu

    2004-10-01

    We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of the heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulentlike, cascade heart rate model. These results strongly support the view that a healthy human heart rate is controlled to converge continually to a critical state.

  11. Drowsiness detection using heart rate variability.

    PubMed

    Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

    2016-06-01

    It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems.

  12. Drowsiness detection using heart rate variability.

    PubMed

    Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

    2016-06-01

    It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems. PMID:26780463

  13. Regional Neurodegeneration and Gliosis Are Amplified by Mild Traumatic Brain Injury Repeated at 24-Hour Intervals

    PubMed Central

    Bolton, Amanda Nicholle; Saatman, Kathryn Eileen

    2014-01-01

    Most traumatic brain injuries (TBIs) that occur every year are classified as ‘mild’. Individuals involved in high-risk activities may sustain multiple mild TBIs. We evaluated the acute physiological and histopathological consequences of mild TBI in a mouse model, comparing sham injury, single impact, or 5 impacts at a 24- or 48-hour inter-injury interval. A single closed skull impact resulted in bilateral gliosis in the hippocampus and entorhinal cortex that was proportional to impact depth. Midline impact, at a depth just above the threshold to induce transient unconsciousness, produced occasional axonal injury and degenerating neurons accompanied by astrogliosis in the entorhinal cortex and cerebellum. Mild TBI repeated every 24 hours resulted in bilateral hemorrhagic lesions in the entorhinal cortex along with significantly increased neurodegeneration and microglial activation despite diminished durations of apnea and unconsciousness with subsequent impacts. Astrogliosis and diffusely distributed axonal injury were also observed bilaterally in the cerebellum and the brainstem. When the interval between mild TBIs was increased to 48 hours, the pathological consequences were comparable to a single TBI. Together, these data suggest that in mice the brain remains at increased risk for damage for 24 hours after mild TBI despite reduced acute physiological responses to subsequent mild impacts. PMID:25232942

  14. A Compute Perspective: Delivering Decision Support Products in 24 Hours from the Airborne Snow Observatory

    NASA Astrophysics Data System (ADS)

    Ramirez, P.; Mattmann, C. A.; Painter, T. H.; Seidel, F. C.; Trangsrud, A.; Hart, A. F.; Goodale, C. E.; Boardman, J. W.; Heneghan, C.; Verma, R.; Khudikyan, S.; Boustani, M.; Zimdars, P. A.; Horn, J.; Neely, S.

    2013-12-01

    The JPL Airborne Snow Observatory (ASO) must process 100s of GB of raw data to 100s of Terabytes of derived data in 24 hour Near Real Time (NRT) latency in a geographically distributed mobile compute and data-intensive processing setting. ASO provides meaningful information to water resource managers in the Western US letting them know how much water to maintain; or release, and what the prospectus of the current snow season is in the Sierra Nevadas. Providing decision support products processed from airborne data in a 24 hour timeframe is an emergent field and required the team to develop a novel solution as this process is typically done over months. We've constructed a system that combines Apache OODT; with Apache Tika; with the Interactive Data Analysis (IDL)/ENVI programming environment to rapidly and unobtrusively generate, distribute and archive ASO data as soon as the plane lands near Mammoth Lakes, CA. Our system is flexible, underwent several redeployments and reconfigurations, and delivered this critical information to stakeholders during the recent "Snow On" campaign March 2013 - June 2013. This talk will take you through a day in the life of the compute team from data acquisition, delivery, processing, and dissemination. Within this context, we will discuss the architecture of ASO; the open source software we used; the data we stored; and how it was delivered to its users. Moreover we will discuss the logistics, system engineering, and staffing that went into the developing, deployment, and operation of the mobile compute system.

  15. Coagulation abnormalities in diabetic coma before and 24 hours after treatment.

    PubMed

    McLaren, E H; Cullen, D R; Brown, M J

    1979-12-01

    A coagulation screen consisting of measurement of the prothrombin time, thrombin time, kaolin caphalin clotting time, platelet count, plasma fibrinogen level, fibrin degradation products and ethanol gelation test was performed on 24 patients with impairment of consciousness due to acute diabetic metabolic decompensation at the start of treatment and 24 hours later. 22 out of 24 patients showed at least one coagulation abnormality on admission of which the commonest were a prolonged prothrombin time, shortened kaolin cephalin clotting.time and raised plasma fibrinogen level. After 24 hours of treatment these values were more normal but 20 out of 22 patients still displayed some abnormality. 15 patients had two or more coagulation abnormalities on admission including 3 patients with haematological abnormalities suggestive of disseminated intravascular coagulation. This group was older and had higher blood ureas than those with fewer abnormalities, but plasma glucose, sodium, potassium and bicarbonate levels were similar in both groups of patients. All 5 patients with hyperosmolar non-ketotic coma and all 3 patients who died without recovering consciousness had two or more coagulation abnormalities on admission.

  16. Deviation of innate circadian period from 24 hours reduces longevity in mice

    PubMed Central

    Libert, Sergiy; Bonkowski, Michael S.; Pointer, Kelli; Pletcher, Scott D.; Guarente, Leonard

    2012-01-01

    Summary The variation of individual lifespans, even in highly inbred cohorts of animals and under strictly controlled environmental conditions, is substantial and not well understood. This variation in part could be due to epigenetic variation, which later affects the animal’s physiology and ultimately longevity. Identification of the physiological properties that impact health and lifespan is crucial for longevity research and the development of anti-aging therapies. Here we measured individual circadian and metabolic characteristics in a cohort of inbred F1 hybrid mice and correlated these parameters to their lifespans. We found that mice with innate circadian periods close to 24 hours (revealed during 30 days of housing in total darkness) enjoyed nearly 20% longer lifespans than their littermates, which had shorter or longer innate circadian periods. These findings show that maintenance of a 24 hour intrinsic circadian period is a positive predictor of longevity. Our data suggest that circadian period may be used to predict individual longevity and that processes that control innate circadian period affect aging. PMID:22702406

  17. Sleep in healthy elderly subjects: a 24-hour ambulatory polysomnographic study.

    PubMed

    Gigli, G L; Placidi, F; Diomedi, M; Maschio, M; Silvestri, G; Scalise, A; Marciani, M G

    1996-04-01

    It is still debated whether the deterioration of the sleep pattern, frequently reported by elderly subjects, is due only to aging per se. Other factors associated with aging or modifications of biological rhythms could also be involved. Elderly subjects frequently complain of daytime sleepiness, but it is not clear whether this actually represents a return to a polyphasic structure of sleep, or only a consequence of a disturbed night sleep. Ten healthy, independent and active elderly subjects (age > 72 years) were elevated by means of 24-hour ambulatory polysomnography. Findings of nocturnal sleep were compared with sleep of the same group in the 24-hour period and with sleep of young healthy controls. We observed a fragmentation of nocturnal sleep, but a fairly good representation of stages and a preservation of cyclicity. Except for three cases, with early or late times of sleep onset and wake-up, sleep disruption did not seem to be related to modification of circadian rhythms. Only three subjects presented undesired daytime naps, whereas the others either did not show daytime sleep at all, or were used to having their siesta after lunch since their young adulthood. In normal aging, daytime sleep does not constitute a social problem. Ambulatory polysomnography is a valid alternative to laboratory recordings in the identification of daytime sleep. PMID:8734563

  18. PHYSICIAN-PHARMACIST CO-MANAGEMENT AND 24-HOUR BLOOD PRESSURE CONTROL

    PubMed Central

    Chen, Ziqian; Ernst, Michael E.; Ardery, Gail; Xu, Yinghui; Carter, Barry L.

    2013-01-01

    The objectives of this study were: to compare indices of 24-hour BP following a physician-pharmacist collaborative intervention and to describe the associated changes in antihypertensive medications. This was a secondary analysis of a prospective, cluster-randomized clinical trial conducted in 6 family medicine clinics randomized to co-managed (n=3 clinics, 176 subjects) or control (n=3 clinics, 198 subjects) groups. Mean ambulatory systolic BP was significantly lower in the co-managed versus the control group: daytime SBP 122.8 mm Hg versus 134.4 mm Hg (p<0.001); nighttime SBP 114.8 mm Hg versus 123.7 mm Hg (p<0.001); and 24-hour SBP 120.4 mm Hg versus 131.8 mm Hg (p<0.001), respectively. Significantly more drug changes were made in the co-managed than in the control group (2.7 versus 1.1 changes/subject, p<0.001), and there was greater diuretic use in co-managed subjects (79.6% versus 62.6%, p<0.001). Ambulatory BPs were significantly lower for the subjects who had a diuretic added during the first month compared with those who never had a diuretic added (p<0.01). Physician-pharmacist co-management significantly improved ambulatory BP compared with a control group. Anti-hypertensive drug therapy was intensified much more for subjects in the co-managed group. PMID:23614849

  19. Significance, prognostic value and management of heart rate in hypertension.

    PubMed

    Courand, Pierre-Yves; Lantelme, Pierre

    2014-01-01

    Many epidemiological studies have demonstrated that resting heart rate is a risk marker but also a risk factor in patients with coronary artery disease and heart failure. In hypertensive subjects free from overt cardiac disease, the question has been less frequently addressed. A few cohort studies have shown that hypertensive patients with a high resting heart rate have an increased risk of all-cause and cardiovascular death. However, intervention trials have not demonstrated that lowering the heart rate is beneficial in hypertensive subjects. Studies with an assessment of ambulatory heart rate tend to demonstrate a better association between cardiovascular outcomes and variables, including nighttime heart rate. Clinical trials comparing beta-blockers with non-slowing antihypertensive drugs have not demonstrated the superiority of the former. Finally, an elevated resting heart rate in hypertensive subjects free from overt cardiac disease seems to be more a risk marker than a risk factor. Although these patients are at high risk, no scientific data exist to support targeting heart rate. In this review, we describe the pathophysiological effects of heart rate, including vascular cell signalling, link with sympathetic activity and influence on central blood pressure, and the prognostic value and management of HR in hypertensive patients free from overt cardiac diseases.

  20. Heart Rate and Risk of Cancer Death in Healthy Men

    PubMed Central

    Jouven, Xavier; Escolano, Sylvie; Celermajer, David; Empana, Jean-Philippe; Bingham, Annie; Hermine, Olivier; Desnos, Michel; Perier, Marie-Cécile; Marijon, Eloi; Ducimetière, Pierre

    2011-01-01

    Background Data from several previous studies examining heart-rate and cardiovascular risk have hinted at a possible relationship between heart-rate and non-cardiac mortality. We thus systematically examined the predictive value of heart-rate variables on the subsequent risk of death from cancer. Methods In the Paris Prospective Study I, 6101 asymptomatic French working men aged 42 to 53 years, free of clinically detectable cardiovascular disease and cancer, underwent a standardized graded exercise test between 1967 and 1972. Resting heart-rate, heart-rate increase during exercise, and decrease during recovery were measured. Change in resting heart-rate over 5 years was also available in 5139 men. Mortality including 758 cancer deaths was assessed over the 25 years of follow-up. Findings There were strong, graded and significant relationships between all heart-rate parameters and subsequent cancer deaths. After adjustment for age and tobacco consumption and, compared with the lowest quartile, those with the highest quartile for resting heart-rate had a relative risk of 2.4 for cancer deaths (95% confidence interval: 1.9–2.9, p<0.0001) This was similar after adjustment for traditional cardiovascular risk factors and was observed for the commonest malignancies (respiratory and gastrointestinal). Similarly, significant relationships with cancer death were observed between poor heart rate increase during exercise, poor decrease during recovery and greater heart-rate increase over time (p<0.0001 for all). Interpretation Resting and exercise heart rate had consistent, graded and highly significant associations with subsequent cancer mortality in men. PMID:21826196

  1. Parasympathetic heart rate modulation during parabolic flights.

    PubMed

    Beckers, F; Seps, B; Ramaekers, D; Verheyden, B; Aubert, A E

    2003-09-01

    During parabolic flight short periods of microgravity and hypergravity are created. These changes influence cardiovascular function differently according to posture. During the 29th parabolic flight campaign of the European Space Agency (ESA), the electrocardiogram (ECG) was recorded continuously in seven healthy volunteers in two positions (standing and supine). Five different phases were differentiated: 1 g (1 g=9.81 m/s(2)) before and after each parabola, 1.8 g at the ascending leg of the parabola (hypergravity), 0 g at the apex, 1.6 g at the descending leg (hypergravity). We assessed heart rate variability (HRV) by indices of temporal analysis [mean RR interval (meanRR), the standard deviation of the intervals (SDRR), and the square root of the mean squared differences of successive intervals (rMSSD) and coefficient of variation (CV)]. In the supine position no significant differences were shown between different gravity phases for all HRV indices. In the standing position the 0 g phase showed a tendency towards higher values of meanRR compared to the control and to the other phases ( p=NS). SDRR, rMSSD and CV were significantly higher compared to control ( p<0.05). Significantly higher values for meanRR in the supine position at 1 g and hypergravity ( p<0.05) were found when compared to standing. SDRR was significantly higher at 0 g in the standing position compared to supine [95 (44) ms vs. 50 (15) ms; p<0.05] and lower in other phases. rMSSD and CV showed the same trend ( p=NS). We confirm that, during parabolic flights, position matters for cardiovascular measurements. Time domain indices of HRV during different gravity phases showed: (1) higher vagal modulation of the autonomic nervous system in microgravity, when compared with normo- or hypergravity in standing subjects; and (2) no differences in supine subjects between different g phases.

  2. Association between Sleep Duration and 24-Hour Urine Free Cortisol in the MrOS Sleep Study

    PubMed Central

    Rao, Madhu N.; Blackwell, Terri; Redline, Susan; Punjabi, Naresh M.; Barrett-Connor, Elizabeth; Neylan, Thomas C.; Stone, Katie L.

    2013-01-01

    Context Short sleep duration is associated with adverse health outcomes, but the mechanisms involved are unknown. It has been postulated that short sleep duration may elevate cortisol levels, but studies have had conflicting results. It is unclear whether these differing findings may be due to methodological issues, such as assessment of sleep duration. Specifically, objective versus subjective methods of measuring habitual sleep duration may account for the conflicting results found in epidemiological studies. Objective Our goal was to determine whether habitual sleep duration, measured objectively (by actigraphy) and subjectively (by self-report), was associated with 24-hour urine free cortisol (UFC), a measure of integrated cortisol secretion. Our secondary goal was to determine whether slow wave sleep (SWS, determined by polysomnography) was associated with 24-hour UFC. Design/Setting Cross sectional study of community dwelling older men. Patients/Participants 325 men (mean age = 76.6 years, SD = 5.5) from the Portland site of the MrOS Sleep Study, who underwent 24-hour urine collection, polysomnography, actigraphy and sleep questionnaire. Primary Outcome 24-hour UFC. Results In this study of community dwelling older men, self-reported sleep duration was inversely related to 24-hour UFC levels. Participants reporting <5 hours of habitual sleep had an adjusted mean 24-hour UFC of 29.8 ug, compared to 28.0 ug in participants reporting >5 to <8 hours of sleep 25.5 ug in those reporting >8 hours of habitual sleep. However, sleep duration determined by actigraphy was not associated with 24-hour UFC in either univariable or multivariable regression models. SWS was not associated with 24-hour UFC. Conclusion Objectively measured (i.e., actigraphic) sleep duration is not associated with 24-hour UFC in these community dwelling older men. This finding, together with prior studies, suggests that elevated levels of integrated cortisol secretion is not the

  3. Using Target Heart-Rate Zones in Your Class

    ERIC Educational Resources Information Center

    Gilbert, Jennie A.

    2005-01-01

    Should teachers teach the calculation of target heart rate to students? And when is it appropriate to engage students in the attainment of these heart rates during physical education class activities? The answers to these questions are not easy. One might be tempted to state a simple yes or no and to identify a specific age to begin using training…

  4. Neuronal control of heart rate in isolated mouse atria.

    PubMed

    Choate, J K; Feldman, R

    2003-09-01

    A novel mouse isolated atrial preparation with intact postganglionic autonomic innervation was used to investigate the neuronal control of heart rate. To establish whether autonomic activation was likely to alter heart rate by modulating the hyperpolarization-activated current (If), the L-type Ca2+ current (ICa,L), or the ACh-activated K+ current (IK,ACh), the effects of nerve stimulation (right stellate ganglion or right vagus, 1-30 Hz) and autonomic agonists (0.1 microM norepinephrine or 0.3 microM carbachol) on heart rate were investigated in the presence of inhibitors of these currents, cesium chloride (Cs+, 1 mM), nifedipine (200 nM), and barium chloride (Ba2+, 0.1 mM), respectively. The positive chronotropic response to stellate ganglion stimulation was reduced by approximately 20% with Cs+ and nifedipine (P < 0.05), whereas the heart rate response to norepinephrine was only reduced with Cs+ (P < 0.05). Ba2+ attenuated the decrease in heart rate with vagal stimulation and carbachol by approximately 60% (P < 0.05). These results are consistent with the idea that sympathetic nerve stimulation modulates If to increase heart rate in the mouse. Activation of ICa,L also appears to contribute to the sympathetic heart rate response. However, the decrease in heart rate with vagal stimulation or carbachol is likely to result primarily from the activation of IK,ACh.

  5. Effect of Age and Other Factors on Maximal Heart Rate.

    ERIC Educational Resources Information Center

    Londeree, Ben R.; Moeschberger, Melvin L.

    1982-01-01

    To reduce confusion regarding reported effects of age on maximal exercise heart rate, a comprehensive review of the relevant English literature was conducted. Data on maximal heart rate after exercising with a bicycle, a treadmill, and after swimming were analyzed with regard to physical fitness and to age, sex, and racial differences. (Authors/PP)

  6. Assessing Heart Rate in Physical Education. Assessment Series: K-12 Physical Education.

    ERIC Educational Resources Information Center

    Buck, Marilyn M.

    This guide discusses the assessment of heart rate and, in particular, the assessment of heart rate using a heart monitor. Part 1, "Foundation for the Use of Heart Rate," reviews literature about heart rate assessment and heart rate monitors, offering an overview of national guidelines for physical activity. It focuses on the importance of physical…

  7. Effects of Tai Chi exercise on heart rate variability.

    PubMed

    Cole, Aimee R; Wijarnpreecha, Karn; Chattipakorn, Siriporn C; Chattipakorn, Nipon

    2016-05-01

    Tai Chi is a callisthenic exercise form that incorporates aerobic exercise with diaphragmatic breathing. These two aspects alone have been shown to enhance the heart rate variability, warranting research into the effects of Tai Chi on autonomic nervous system modulation and heart rate variability. A low heart rate variability has been shown to be indicative of compromised health. Any methods to enhance the heart rate variability, in particular, non-pharmacological methods, are therefore seen as beneficial to health and are sought after. The aim of this review was to comprehensively summarize the currently published studies regarding the effects of Tai Chi on heart rate variability. Both consistent and inconsistent findings are presented and discussed, and an overall conclusion attained which could benefit future clinical studies.

  8. Turbulent diffusion on the solar photosphere through 24-hour continuous observations of magnetic elements

    NASA Astrophysics Data System (ADS)

    Giannattasio, F.; Berrilli, F.; Del Moro, D.; Bellot Rubio, L.; Orozco Suarez, D.; Gosic, M.

    2012-12-01

    Solar atmosphere is a unique laboratory for the study of turbulent flows under extreme conditions (e.g. very high Reynolds numbers). The turbulent nature of the flow may be approached by determining how magnetic flux elements are transported on the solar surface, and measuring the spatio-temporal scales on which these small magnetic structures are organized. The process involved is diffusion. Several works explored this topic, both by simulations and observations, and the results are often contradictory, ranging from fully-developed turbulent scenarios to normal-diffusive motions. We analyze 24-hour continuous Hinode SOT observations of a supergranular region (for the first time these long scales are explored), studying the evolution of the mutual distance between magnetic element pairs and its scaling laws, in order to investigate the diffusion process. We find a super-diffusive behavior, with a gamma index depending on the spatial scale selected.

  9. After 24-hour scrub, another tower rollback for the Boeing Delta II rocket carrying Stardust

    NASA Technical Reports Server (NTRS)

    1999-01-01

    As tower rollback begins, the Boeing Delta II rocket carrying the Stardust spacecraft waits on Launch Pad 17-A, Cape Canaveral Air Station, for the second launch attempt at 4:04 p.m. EST. The original launch was scrubbed on Feb. 6 for 24 hours. Stardust is destined for a close encounter with the comet Wild 2 in January 2004. Using a silicon-based substance called aerogel, Stardust will capture comet particles flying off the nucleus of the comet. The spacecraft also will bring back samples of interstellar dust. These materials consist of ancient pre-solar interstellar grains and other remnants left over from the formation of the solar system. Scientists expect their analysis to provide important insights into the evolution of the sun and planets and possibly into the origin of life itself. The collected samples will return to Earth in a sample return capsule to be jettisoned as Stardust swings by Earth in January 2006.

  10. Chest physiotherapy in preterm infants with RDS in the first 24 hours of life.

    PubMed

    Raval, D; Yeh, T F; Mora, A; Cuevas, D; Pyati, S; Pildes, R S

    1987-01-01

    To evaluate if chest physiotherapy is beneficial to premature infants with respiratory distress syndrome (RDS) during the first 24 hours of life, 20 infants were randomly assigned to two groups; 10 infants in Group I received routine chest physiotherapy and suction, and 10 infants in Group II received suction only. The birth weight, gestational age, postnatal age, Apgar scores, blood gases, acid-base status, and ventilatory requirements prior to study were comparable between the two groups. There were no significant differences between the groups in the amount of endotracheal secretions removed, the PO2/FIO2 ratio, blood gases, and pH during the study. The incidence of patent ductus arteriosus (PDA), bronchopulmonary dysplasia (BPD), Grade I and II intraventricular hemorrhage (IVH), and mortality was comparable. However, five of 10 Group I and zero of 10 Group II infants developed Grade III or IV IVH (P less than 0.05).

  11. [Development of direct and indirect ambulatory 24-hour blood pressure monitoring].

    PubMed

    Krönig, B

    1991-01-01

    The direct ambulatory 24-hour blood-pressure monitoring has been applied in two ways. With the so called "Oxford-system", blood pressure is recorded via a cannula in the brachial artery which is connected to a perfusion unit that is worn around the neck, on the front of the chest, with a tape recorder carried in a pouch on the patient's belt. Using the micro-catheter blood-pressure telemetry recording is done in the same way, but transmission of the data to a stationary-receiving unit is managed by telemetry. The usage of the latter method is limited by the weight and complexity of the patient-sited equipment. Compared to the Oxford-system there is the advantage of continuously observing the patients blood-pressure "on-line" during the recording. The invasive character of both methods limits the application to special, scientific investigations. In recent years the indirect recording machines for 24-hour blood-pressure monitoring has been developed further. They are now accurate, easy to apply and simple to work out. Beside the auscultatory way of recording, with or without ECG-gating, the oscillometry recording machines have been improved. There should be automatically-operated intervals with recordings in day-time every 15-20 minutes and during the night every 30 minutes. The recorded data should be analysed by computer, calculating mean values with standard deviations in day-time and night-time separately. Further more, there should be a listing of reading-errors and probably corrected measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Low correlation between visit-to-visit variability and 24-hour variability of blood pressure

    PubMed Central

    Muntner, Paul; Shimbo, Daichi; Diaz, Keith M.; Newman, Jonathan; Sloan, Richard P.; Schwartz, Joseph E.

    2013-01-01

    Visit-to-visit variability (VVV) of clinic systolic blood pressure (SBP) has been associated with cardiovascular disease risk. Given the need for obtaining blood pressure (BP) at multiple visits to calculate VVV, substituting BP variability from ambulatory blood pressure monitoring (ABPM) may be a practical alternative. We assessed the correlation between VVV of BP and BP variability from ABPM using data from 146 untreated, mostly normotensive participants (mean age 47.9 years) in a substudy of the ongoing Masked Hypertension Study. VVV of SBP and diastolic blood pressure (DBP) was estimated by the standard deviation (SDvvv) and average real variability (ARVvvv) from 6 study visits over a median of 216 days. ABPM data were used to calculate the day-night SD (SDdn) and the ARV of SBP and DBP over 24 hours (ARV24). For SBP, the mean SDvvv and SDdn were 6.3 (SD=2.5) and 8.8 (SD=1.8) mmHg, respectively, and mean ARVvvv and ARV24 were 7.2 (SD=3.2) and 8.4 (SD=2.1) mmHg, respectively. The Spearman correlation coefficient between SDvvv and SDdn of SBP was rs=0.25 and between ARVvvv and ARV24 was rs=0.17. Participants in the highest quartile of SDdn of SBP were 1.66 (95% CI: 0.93 – 2.75) times more likely to be in the highest quartile of SDvvv of SBP. The observed-to-expected ratio between the highest quartiles of ARVvvv and ARV24 of SBP was 0.89 (95% CI: 0.41 – 1.69). The correlations for SDvvv and SDdn and ARVvvv and ARV24 of DBP were minimal. These data suggest VVV and 24-hour variability are weakly correlated and not interchangeable. PMID:23784506

  13. [Use of fourier row as a method for analyzing the course of circadian heart rate in patients with left ventricular ejection fraction impairment].

    PubMed

    Walichiewicz, P; Mrózek, A; Rozentryt, P; Wilczek, K; Jacheć, W; Wodniecki, J; Szyguła, E; Wantrych, M

    1998-06-01

    The circadian heart rate course was assessed in 3 groups of patients with left ventricular ejection fraction (LVEF) 10-15%, 20-25% and 30-35%. The study comprised 36 persons. In 9 patients heart failure was due to MI and in 17--to dilated cardiomyopathy. Those with atrial fibrillation, ventricular tachycardia, supraventricular tachycardia, diabetes, valvular heart diseases and with central system disorders were excluded from the study. Left ventricular ejection fraction was evaluated by echocardiography. Heart rate, calculated as a mean value every 5 minutes, was taken in patients during 24 hour recordings. For each patient separately, mean value of all measurement was calculated. Then a ratio of each actual value to the mean value was calculated. This ratio was defined as relative heart rate; [formula: see text] Circadian heart rate courses were approximated by Fourier row: [formula: see text]. The 24 harmonics were analyzed. Statistically significant differences in circadian courses were closed to amplitudes of 1st, 12th, 13th, 14th, 16th, 18th harmonics. Using test of variance homogeneity it has been demonstrated that variability of amplitudes of 12th and 17th harmonics as well as phase of 5th harmonic depend on left ventricular ejection fraction.

  14. The effect of heart rate on the heart rate variability response to autonomic interventions.

    PubMed

    Billman, George E

    2013-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate (HR) or heart period (R-R interval), has become a popular clinical and investigational tool to quantify cardiac autonomic regulation. However, it is not widely appreciated that, due to the inverse curvilinear relationship between HR and R-R interval, HR per se can profoundly influence HRV. It is, therefore, critical to correct HRV for the prevailing HR particularly, as HR changes in response to autonomic neural activation or inhibition. The present study evaluated the effects of HR on the HRV response to autonomic interventions that either increased (submaximal exercise, n = 25 or baroreceptor reflex activation, n = 20) or reduced (pharmacological blockade: β-adrenergic receptor, muscarinic receptor antagonists alone and in combination, n = 25, or bilateral cervical vagotomy, n = 9) autonomic neural activity in a canine model. Both total (RR interval standard deviation, RRSD) and the high frequency (HF) variability (HF, 0.24-1.04 Hz) were determined before and in response to an autonomic intervention. All interventions that reduced or abolished cardiac parasympathetic regulation provoked large reductions in HRV even after HR correction [division by mean RRsec or (mean RRsec)(2) for RRSD and HF, respectively] while interventions that reduced HR yielded mixed results. β-adrenergic receptor blockade reduced HRV (RRSD but not HF) while both RRSD and HF increased in response to increases in arterial blood (baroreceptor reflex activation) even after HR correction. These data suggest that the physiological basis for HRV is revealed after correction for prevailing HR and, further, that cardiac parasympathetic activity is responsible for a major portion of the HRV in the dog.

  15. Toward Capturing Momentary Changes of Heart Rate Variability by a Dynamic Analysis Method

    PubMed Central

    Zhang, Haoshi; Zhu, Mingxing; Zheng, Yue; Li, Guanglin

    2015-01-01

    The analysis of heart rate variability (HRV) has been performed on long-term electrocardiography (ECG) recordings (12~24 hours) and short-term recordings (2~5 minutes), which may not capture momentary change of HRV. In this study, we present a new method to analyze the momentary HRV (mHRV). The ECG recordings were segmented into a series of overlapped HRV analysis windows with a window length of 5 minutes and different time increments. The performance of the proposed method in delineating the dynamics of momentary HRV measurement was evaluated with four commonly used time courses of HRV measures on both synthetic time series and real ECG recordings from human subjects and dogs. Our results showed that a smaller time increment could capture more dynamical information on transient changes. Considering a too short increment such as 10 s would cause the indented time courses of the four measures, a 1-min time increment (4-min overlapping) was suggested in the analysis of mHRV in the study. ECG recordings from human subjects and dogs were used to further assess the effectiveness of the proposed method. The pilot study demonstrated that the proposed analysis of mHRV could provide more accurate assessment of the dynamical changes in cardiac activity than the conventional measures of HRV (without time overlapping). The proposed method may provide an efficient means in delineating the dynamics of momentary HRV and it would be worthy performing more investigations. PMID:26172953

  16. Learning by Heart: Students Use Heart Rate Patterns To Identify Nervous System Imbalances.

    ERIC Educational Resources Information Center

    Ackerly, Spafford C.

    2001-01-01

    Introduces a science unit on heart rate variability (HVR) patterns. Uses spectral analysis to determine the effects of environmental stimulants such as music and emotional stress on heart rate. Observes relaxation techniques and their effects on the autonomous nervous system. (Contains 12 references.) (YDS)

  17. Symbolic Dynamics Analysis of Short Data Sets: an Application to Heart Rate Variability from Implantable Defibrillator Devices

    NASA Astrophysics Data System (ADS)

    Zebrowski, Jan J.; Baranowski, Rafal; Przybylski, Andrzej

    2003-07-01

    A method is described for the assessment of the complexity of short data sets by nonlinear dynamics. The method was devised for and tested on human heart rate recordings approximately 2000 to 9000 RR intervals long which were extracted from the memory of implantable defibrillator devices (ICD). It is, however, applicable in a more general context. The ICDs are meant to control life-threatening episodes of ventricular tachycardia and/or ventricular fibrillation by applying a electric shock to the heart through intracardiac electrodes. It is well known that conventional ICD algorithms yield approximately 20--30 % of spurious interventions. The main aim of this work is to look for nonlinear dynamics methods to enhance the appropriateness of the ICD intervention. We first showed that nonlinear dynamics methods first applied to 24-hour heart rate variability analysis were able to detect the need for the ICD intervention. To be applicable to future ICD use, the methods must also be low in computational requirements. Methods to analyse the complexity of the short and non-stationary sets were devised. We calculated the Shannon entropy of symbolic words obtained in a sliding 50 beat window and analysed the dependence of this complexity measure on the time. Precursors were found extending much earlier time than the time the standard ICD algorithms span.

  18. Heart rate and heart rate variability modification in chronic insomnia patients.

    PubMed

    Farina, Benedetto; Dittoni, Serena; Colicchio, Salvatore; Testani, Elisa; Losurdo, Anna; Gnoni, Valentina; Di Blasi, Chiara; Brunetti, Riccardo; Contardi, Anna; Mazza, Salvatore; Della Marca, Giacomo

    2014-01-01

    Chronic insomnia is highly prevalent in the general population, provoking personal distress and increased risk for psychiatric and medical disorders. Autonomic hyper-arousal could be a pathogenic mechanism of chronic primary insomnia. The aim of this study was to investigate autonomic activity in patients with chronic primary insomnia by means of heart rate variability (HRV) analysis. Eighty-five consecutive patients affected by chronic primary insomnia were enrolled (38 men and 47 women; mean age: 53.2 ± 13.6). Patients were compared with a control group composed of 55 healthy participants matched for age and gender (23 men and 32 women; mean age: 54.2 ± 13.9). Patients underwent an insomnia study protocol that included subjective sleep evaluation, psychometric measures, and home-based polysomnography with evaluation of HRV in wake before sleep, in all sleep stages, and in wake after final awakening. Patients showed modifications of heart rate and HRV parameters, consistent with increased sympathetic activity, while awake before sleep and during Stage-2 non-REM sleep. No significant differences between insomniacs and controls could be detected during slow-wave sleep, REM sleep, and post-sleep wake. These results are consistent with the hypothesis that autonomic hyper-arousal is a major pathogenic mechanism in primary insomnia, and confirm that this condition is associated with an increased cardiovascular risk.

  19. Patterns of physical activity determined by heart rate monitoring among diabetic children

    PubMed Central

    Massin, M; Lebrethon, M; Rocour, D; Gerard, P; Bourguignon, J

    2005-01-01

    Background: Children with type 1 diabetes should be encouraged to participate in physical activity because exercise can benefit insulin sensitivity and improve known risk factors for atherosclerosis. Methods: Physical activity patterns of 127 children and adolescents with stable type 1 diabetes were investigated by 24 hour continuous heart rate monitoring. The percentage of heart rate reserve was used to measure the amounts of physical activity at different intensities. The results were compared with normative data. Results: Diabetic preschoolchildren accumulated 192.7 (78.1), 39.1 (24.3), and 21.3 (9.4) minutes/day (mean (SD)) of light, moderate, and vigorous physical activity, respectively. At the same activity levels, diabetic schoolchildren accumulated 168.9 (76.7), 37.9 (15.9), and 19.0 (14.8) minutes/day, and diabetic teenagers accumulated 166.3 (67.5), 45.6 (26.9), and 25.2 (15.3) minutes/day. Diabetic schoolchildren were significantly more active than healthy peers when considering moderate activity; diabetic teenagers were significantly more active when considering moderate and vigorous activity. There was a negative correlation between the most recent glycated haemoglobin and the time spent in light activities in schoolchildren, and a negative correlation between mean glycated haemoglobin for one year and time spent in light and moderate activities in schoolchildren. Conclusion: The majority of our diabetic patients meet the classical paediatric guidelines for physical activity and compare favourably with their healthy peers. PMID:15941770

  20. Attempt Quit Smoking 24+ Hours Maps and Data of Model-Based Small Area Estimates - Small Area Estimates

    Cancer.gov

    Attempt Quit Smoking 24+ Hours is defined as a person 18 years of age or older who must have reported smoking at least 100 cigarettes in his/her life, and now does not smoke at all but it has been less than 365 days since completely stopped smoking cigarettes, or now smoke everyday or some days but reported that have made attempt of quitting for more than 24 hours in the past 12 months.

  1. Remote measurement of cognitive stress via heart rate variability.

    PubMed

    McDuff, Daniel; Gontarek, Sarah; Picard, Rosalind

    2014-01-01

    Remote detection of cognitive load has many powerful applications, such as measuring stress in the workplace. Cognitive tasks have an impact on breathing and heart rate variability (HRV). We show that changes in physiological parameters during cognitive stress can be captured remotely (at a distance of 3m) using a digital camera. A study (n=10) was conducted with participants at rest and under cognitive stress. A novel five band digital camera was used to capture videos of the face of the participant. Significantly higher normalized low frequency HRV components and breathing rates were measured in the stress condition when compared to the rest condition. Heart rates were not significantly different between the two conditions. We built a person-independent classifier to predict cognitive stress based on the remotely detected physiological parameters (heart rate, breathing rate and heart rate variability). The accuracy of the model was 85% (35% greater than chance). PMID:25570611

  2. Thermal Acclimation of Heart Rates in Reptilian Embryos

    PubMed Central

    Du, Wei-Guo; Ye, Hua; Zhao, Bo; Warner, Daniel A.; Shine, Richard

    2010-01-01

    In many reptiles, the thermal regimes experienced by eggs in natural nests vary as a function of ambient weather and location, and this variation has important impacts on patterns of embryonic development. Recent advances in non-invasive measurement of embryonic heart rates allow us to answer a long-standing puzzle in reptilian developmental biology: Do the metabolic and developmental rates of embryos acclimate to local incubation regimes, as occurs for metabolic acclimation by post-hatching reptiles? Based on a strong correlation between embryonic heart rate and oxygen consumption, we used heart rates as a measure of metabolic rate. We demonstrate acclimation of heart rates relative to temperature in embryos of one turtle, one snake and one lizard species that oviposit in relatively deep nests, but found no acclimation in another lizard species that uses shallow (and hence, highly thermally variable) nests. Embryonic thermal acclimation thus is widespread, but not ubiquitous, within reptiles. PMID:21179473

  3. [Association between level of intelligence and heart rate variability].

    PubMed

    Mukhin, V N; Iakovlev, N M

    2011-08-01

    Earlier we discovered that heart rate variability was associated with the level of intelligence. The purpose of this study is to confirm this association using more reliable method and to define more precisely the frequency band within which the amplitude of the heart rate modulations is related to intelligence. 13 males (aged 14 to 17) were the study subjects. The total score of the computer game Tetris was taken as a general measure of the intelligence level. Heart rate was recorded electrocardiographically both at rest and during playing Tetris. Frequency analysis of heart rate was carried out with digital Fourier transformation. Correlation analysis showed that there was positive association between the level of intelligence and the amplitude of heart rate modulation at the frequencies 0.30 and 0.15 modulations per RR interval. This association is closer for the heart rate at rest than for the heart rate during mental work and for the frequency 0.30 than for the 0.15 modulations per RR interval.

  4. Dynamic heart rate estimation using principal component analysis.

    PubMed

    Yu, Yong-Poh; Raveendran, P; Lim, Chern-Loon; Kwan, Ban-Hoe

    2015-11-01

    In this paper, facial images from various video sequences are used to obtain a heart rate reading. In this study, a video camera is used to capture the facial images of eight subjects whose heart rates vary dynamically, between 81 and 153 BPM. Principal component analysis (PCA) is used to recover the blood volume pulses (BVP) which can be used for the heart rate estimation. An important consideration for accuracy of the dynamic heart rate estimation is to determine the shortest video duration that realizes it. This video duration is chosen when the six principal components (PC) are least correlated amongst them. When this is achieved, the first PC is used to obtain the heart rate. The results obtained from the proposed method are compared to the readings obtained from the Polar heart rate monitor. Experimental results show the proposed method is able to estimate the dynamic heart rate readings using less computational requirements when compared to the existing method. The mean absolute error and the standard deviation of the absolute errors between experimental readings and actual readings are 2.18 BPM and 1.71 BPM respectively.

  5. Fractal and complexity measures of heart rate variability.

    PubMed

    Perkiömäki, Juha S; Mäkikallio, Timo H; Huikuri, Heikki V

    2005-01-01

    Heart rate variability has been analyzed conventionally with time and frequency domain methods, which measure the overall magnitude of RR interval fluctuations around its mean value or the magnitude of fluctuations in some predetermined frequencies. Analysis of heart rate dynamics by methods based on chaos theory and nonlinear system theory has gained recent interest. This interest is based on observations suggesting that the mechanisms involved in cardiovascular regulation likely interact with each other in a nonlinear way. Furthermore, recent observational studies suggest that some indexes describing nonlinear heart rate dynamics, such as fractal scaling exponents, may provide more powerful prognostic information than the traditional heart rate variability indexes. In particular, the short-term fractal scaling exponent measured by the detrended fluctuation analysis method has predicted fatal cardiovascular events in various populations. Approximate entropy, a nonlinear index of heart rate dynamics, that describes the complexity of RR interval behavior, has provided information on the vulnerability to atrial fibrillation. Many other nonlinear indexes, e.g., Lyapunov exponent and correlation dimensions, also give information on the characteristics of heart rate dynamics, but their clinical utility is not well established. Although concepts of chaos theory, fractal mathematics, and complexity measures of heart rate behavior in relation to cardiovascular physiology or various cardiovascular events are still far away from clinical medicine, they are a fruitful area for future research to expand our knowledge concerning the behavior of cardiovascular oscillations in normal healthy conditions as well as in disease states.

  6. Dynamic heart rate estimation using principal component analysis

    PubMed Central

    Yu, Yong-Poh; Raveendran, P.; Lim, Chern-Loon; Kwan, Ban-Hoe

    2015-01-01

    In this paper, facial images from various video sequences are used to obtain a heart rate reading. In this study, a video camera is used to capture the facial images of eight subjects whose heart rates vary dynamically, between 81 and 153 BPM. Principal component analysis (PCA) is used to recover the blood volume pulses (BVP) which can be used for the heart rate estimation. An important consideration for accuracy of the dynamic heart rate estimation is to determine the shortest video duration that realizes it. This video duration is chosen when the six principal components (PC) are least correlated amongst them. When this is achieved, the first PC is used to obtain the heart rate. The results obtained from the proposed method are compared to the readings obtained from the Polar heart rate monitor. Experimental results show the proposed method is able to estimate the dynamic heart rate readings using less computational requirements when compared to the existing method. The mean absolute error and the standard deviation of the absolute errors between experimental readings and actual readings are 2.18 BPM and 1.71 BPM respectively. PMID:26601022

  7. A randomized, double-blind comparison of 10 and 20 mg lercanidipine in patients with stable effort angina: effects on myocardial ischemia and heart rate variability.

    PubMed

    Acanfora, Domenico; Trojano, Luigi; Gheorghiade, Mihai; Picone, Costantino; Papa, Antimo; Furgi, Giuseppe; Giuliano, Franca; Maestri, Roberto; Rengo, Franco

    2002-01-01

    We evaluated the anti-ischemic action and the effects on autonomic function of lercanidipine, a long-acting dihydropyridine calcium antagonist, in 25 patients with stable effort angina in a randomized, double-blind, parallel trial. After a 2-week placebo run-in period, patients entered a 2-week treatment period with 10 or 20 mg of lercanidipine once daily. During the placebo run-in period and at the study end, the patients underwent clinical examination, electrocardiography, exercise tests, 24-hour Holter electrocardiography for long-term heart rate variability evaluation, and short-term spectral analysis of heart rate and systolic blood pressure variability and plasma epinephrine and norepinephrine levels at rest and during tilting. Results showed that time to onset of ST segment depression > or =1 mm was significantly increased by both drug doses. No significant change was recorded in the average hourly heart rate after treatment with both 10 and 20 mg of lercanidipine. During the 24-hour recordings, no significant change was observed in low-frequency power, high-frequency power, or low frequency/high frequency. In the standing position, there was a significant increase in plasma norepinephrine and epinephrine concentration in both groups, and no change in the supine position after 10 and 20 mg of lercanidipine. When considering short-term heart rate variability, no significant difference was observed in either treatment group in low frequency, high frequency, or their ratio on electrocardiographic R-R spectra. The blood pressure spectral component was also unchanged. In conclusion, lercanidipine is effective in reducing ischemia in patients with stable effort angina. Moreover, lercanidipine does not cause adrenergic activation, which is the main mechanism hypothesized to explain the negative effect on cardiovascular mortality assigned to short-acting dihydropyridine calcium antagonists.

  8. Accuracy of a Wrist-Worn Wearable Device for Monitoring Heart Rates in Hospital Inpatients: A Prospective Observational Study

    PubMed Central

    Kroll, Ryan R; Boyd, J Gordon

    2016-01-01

    Background As the sensing capabilities of wearable devices improve, there is increasing interest in their application in medical settings. Capabilities such as heart rate monitoring may be useful in hospitalized patients as a means of enhancing routine monitoring or as part of an early warning system to detect clinical deterioration. Objective To evaluate the accuracy of heart rate monitoring by a personal fitness tracker (PFT) among hospital inpatients. Methods We conducted a prospective observational study of 50 stable patients in the intensive care unit who each completed 24 hours of heart rate monitoring using a wrist-worn PFT. Accuracy of heart rate recordings was compared with gold standard measurements derived from continuous electrocardiographic (cECG) monitoring. The accuracy of heart rates measured by pulse oximetry (Spo2.R) was also measured as a positive control. Results On a per-patient basis, PFT-derived heart rate values were slightly lower than those derived from cECG monitoring (average bias of −1.14 beats per minute [bpm], with limits of agreement of 24 bpm). By comparison, Spo2.R recordings produced more accurate values (average bias of +0.15 bpm, limits of agreement of 13 bpm, P<.001 as compared with PFT). Personal fitness tracker device performance was significantly better in patients in sinus rhythm than in those who were not (average bias −0.99 bpm vs −5.02 bpm, P=.02). Conclusions Personal fitness tracker–derived heart rates were slightly lower than those derived from cECG monitoring in real-world testing and not as accurate as Spo2.R-derived heart rates. Performance was worse among patients who were not in sinus rhythm. Further clinical evaluation is indicated to see if PFTs can augment early warning systems in hospitals. Trial Registration ClinicalTrials.gov NCT02527408; https://clinicaltrials.gov/ct2/show/NCT02527408 (Archived by WebCite at  http://www.webcitation.org/6kOFez3on) PMID:27651304

  9. Stochastic heart-rate model can reveal pathologic cardiac dynamics

    NASA Astrophysics Data System (ADS)

    Kuusela, Tom

    2004-03-01

    A simple one-dimensional Langevin-type stochastic difference equation can simulate the heart-rate fluctuations in a time scale from minutes to hours. The model consists of a deterministic nonlinear part and a stochastic part typical of Gaussian noise, and both parts can be directly determined from measured heart-rate data. Data from healthy subjects typically exhibit the deterministic part with two or more stable fixed points. Studies of 15 congestive heart-failure subjects reveal that the deterministic part of pathologic heart dynamics has no clear stable fixed points. Direct simulations of the stochastic model for normal and pathologic cases can produce statistical parameters similar to those of real subjects. Results directly indicate that pathologic situations simplify the heart-rate control system.

  10. Heart Rate Turbulence as Risk-Predictor after Myocardial Infarction

    PubMed Central

    Zuern, Christine S.; Barthel, Petra; Bauer, Axel

    2011-01-01

    Heart rate turbulence (HRT) is the baroreflex-mediated short-term oscillation of cardiac cycle lengths after spontaneous ventricular premature complexes. HRT is composed of a brief heart rate acceleration followed by a gradual heart rate deceleration. In high risk patients after myocardial infarction (MI) HRT is blunted or diminished. Since its first description in 1999 HRT emerged as one of the most potent risk factors after MI. Predictive power of HRT has been studied in more than 10,000 post-infarction patients. This review is intended to provide an overview of HRT as risk-predictor after MI. PMID:22180744

  11. Phase Transition in a Healthy Human Heart Rate

    NASA Astrophysics Data System (ADS)

    Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Togo, Fumiharu; Yamamoto, Yoshiharu

    2005-07-01

    A healthy human heart rate displays complex fluctuations which share characteristics of physical systems in a critical state. We demonstrate that the human heart rate in healthy individuals undergoes a dramatic breakdown of criticality characteristics, reminiscent of continuous second order phase transitions. By studying the germane determinants, we show that the hallmark of criticality—highly correlated fluctuations—is observed only during usual daily activity, and a breakdown of these characteristics occurs in prolonged, strenuous exercise and sleep. This finding is the first reported discovery of the dynamical phase transition phenomenon in a biological control system and will be a key to understanding the heart rate control system in health and disease.

  12. Scaling Behaviour and Memory in Heart Rate of Healthy Human

    NASA Astrophysics Data System (ADS)

    Cai, Shi-Min; Peng, Hu; Yang, Hui-Jie; Zhou, Tao; Zhou, Pei-Ling; Wang, Bing-Hong

    2007-10-01

    We investigate a set of complex heart rate time series from healthy human in different behaviour states with the detrended fluctuation analysis and diffusion entropy (DE) method. It is proposed that the scaling properties are influenced by behaviour states. The memory detected by DE exhibits an approximately same pattern after a detrending procedure. Both of them demonstrate the long-range strong correlations in heart rate. These findings may be helpful to understand the underlying dynamical evolution process in the heart rate control system, as well as to model the cardiac dynamic process.

  13. Time-Based Measurement of Personal Mite Allergen Bioaerosol Exposure over 24 Hour Periods.

    PubMed

    Tovey, Euan R; Liu-Brennan, Damien; Garden, Frances L; Oliver, Brian G; Perzanowski, Matthew S; Marks, Guy B

    2016-01-01

    Allergic diseases such as asthma and rhinitis are common in many countries. Globally the most common allergen associated with symptoms is produced by house dust mites. Although the bed has often been cited as the main site of exposure to mite allergens, surprisingly this has not yet been directly established by measurement due to a lack of suitable methods. Here we report on the development of novel methods to determine the pattern of personal exposure to mite allergen bioaerosols over 24-hour periods and applied this in a small field study using 10 normal adults. Air was sampled using a miniature time-based air-sampler of in-house design located close to the breathing zone of the participants, co-located with a miniature time-lapse camera. Airborne particles, drawn into the sampler at 2L/min via a narrow slot, were impacted onto the peripheral surface of a disk mounted on the hour-hand of either a 12 or 24 hour clock motor. The impaction surface was either an electret cloth, or an adhesive film; both novel for these purposes. Following a review of the time-lapse images, disks were post-hoc cut into subsamples corresponding to eight predetermined categories of indoor or outdoor location, extracted and analysed for mite allergen Der p 1 by an amplified ELISA. Allergen was detected in 57.2% of the total of 353 subsamples collected during 20 days of sampling. Exposure patterns varied over time. Higher concentrations of airborne mite allergen were typically measured in samples collected from domestic locations in the day and evening. Indoor domestic Der p 1 exposures accounted for 59.5% of total exposure, whereas total in-bed-asleep exposure, which varied 80 fold between individuals, accounted overall for 9.85% of total exposure, suggesting beds are not often the main site of exposure. This study establishes the feasibility of novel methods for determining the time-geography of personal exposure to many bioaerosols and identifies new areas for future technical

  14. Non-24-Hour Sleep-Wake Disorder Revisited - A Case Study.

    PubMed

    Garbazza, Corrado; Bromundt, Vivien; Eckert, Anne; Brunner, Daniel P; Meier, Fides; Hackethal, Sandra; Cajochen, Christian

    2016-01-01

    The human sleep-wake cycle is governed by two major factors: a homeostatic hourglass process (process S), which rises linearly during the day, and a circadian process C, which determines the timing of sleep in a ~24-h rhythm in accordance to the external light-dark (LD) cycle. While both individual processes are fairly well characterized, the exact nature of their interaction remains unclear. The circadian rhythm is generated by the suprachiasmatic nucleus ("master clock") of the anterior hypothalamus, through cell-autonomous feedback loops of DNA transcription and translation. While the phase length (tau) of the cycle is relatively stable and genetically determined, the phase of the clock is reset by external stimuli ("zeitgebers"), the most important being the LD cycle. Misalignments of the internal rhythm with the LD cycle can lead to various somatic complaints and to the development of circadian rhythm sleep disorders (CRSD). Non-24-hour sleep-wake disorders (N24HSWD) is a CRSD affecting up to 50% of totally blind patients and characterized by the inability to maintain a stable entrainment of the typically long circadian rhythm (tau > 24.5 h) to the LD cycle. The disease is rare in sighted individuals and the pathophysiology less well understood. Here, we present the case of a 40-year-old sighted male, who developed a misalignment of the internal clock with the external LD cycle following the treatment for Hodgkin's lymphoma (ABVD regimen, four cycles and AVD regimen, four cycles). A thorough clinical assessment, including actigraphy, melatonin profiles and polysomnography led to the diagnosis of non-24-hour sleep-wake disorders (N24HSWD) with a free-running rhythm of tau = 25.27 h. A therapeutic intervention with bright light therapy (30 min, 10,000 lux) in the morning and melatonin administration (0.5-0.75 mg) in the evening failed to entrain the free-running rhythm, although a longer treatment duration and more intense therapy might have

  15. Time-Based Measurement of Personal Mite Allergen Bioaerosol Exposure over 24 Hour Periods

    PubMed Central

    Tovey, Euan R.; Liu-Brennan, Damien; Garden, Frances L.; Oliver, Brian G.; Perzanowski, Matthew S.; Marks, Guy B.

    2016-01-01

    Allergic diseases such as asthma and rhinitis are common in many countries. Globally the most common allergen associated with symptoms is produced by house dust mites. Although the bed has often been cited as the main site of exposure to mite allergens, surprisingly this has not yet been directly established by measurement due to a lack of suitable methods. Here we report on the development of novel methods to determine the pattern of personal exposure to mite allergen bioaerosols over 24-hour periods and applied this in a small field study using 10 normal adults. Air was sampled using a miniature time-based air-sampler of in-house design located close to the breathing zone of the participants, co-located with a miniature time-lapse camera. Airborne particles, drawn into the sampler at 2L/min via a narrow slot, were impacted onto the peripheral surface of a disk mounted on the hour-hand of either a 12 or 24 hour clock motor. The impaction surface was either an electret cloth, or an adhesive film; both novel for these purposes. Following a review of the time-lapse images, disks were post-hoc cut into subsamples corresponding to eight predetermined categories of indoor or outdoor location, extracted and analysed for mite allergen Der p 1 by an amplified ELISA. Allergen was detected in 57.2% of the total of 353 subsamples collected during 20 days of sampling. Exposure patterns varied over time. Higher concentrations of airborne mite allergen were typically measured in samples collected from domestic locations in the day and evening. Indoor domestic Der p 1 exposures accounted for 59.5% of total exposure, whereas total in-bed-asleep exposure, which varied 80 fold between individuals, accounted overall for 9.85% of total exposure, suggesting beds are not often the main site of exposure. This study establishes the feasibility of novel methods for determining the time-geography of personal exposure to many bioaerosols and identifies new areas for future technical

  16. Non-24-Hour Sleep-Wake Disorder Revisited – A Case Study

    PubMed Central

    Garbazza, Corrado; Bromundt, Vivien; Eckert, Anne; Brunner, Daniel P.; Meier, Fides; Hackethal, Sandra; Cajochen, Christian

    2016-01-01

    The human sleep-wake cycle is governed by two major factors: a homeostatic hourglass process (process S), which rises linearly during the day, and a circadian process C, which determines the timing of sleep in a ~24-h rhythm in accordance to the external light–dark (LD) cycle. While both individual processes are fairly well characterized, the exact nature of their interaction remains unclear. The circadian rhythm is generated by the suprachiasmatic nucleus (“master clock”) of the anterior hypothalamus, through cell-autonomous feedback loops of DNA transcription and translation. While the phase length (tau) of the cycle is relatively stable and genetically determined, the phase of the clock is reset by external stimuli (“zeitgebers”), the most important being the LD cycle. Misalignments of the internal rhythm with the LD cycle can lead to various somatic complaints and to the development of circadian rhythm sleep disorders (CRSD). Non-24-hour sleep-wake disorders (N24HSWD) is a CRSD affecting up to 50% of totally blind patients and characterized by the inability to maintain a stable entrainment of the typically long circadian rhythm (tau > 24.5 h) to the LD cycle. The disease is rare in sighted individuals and the pathophysiology less well understood. Here, we present the case of a 40-year-old sighted male, who developed a misalignment of the internal clock with the external LD cycle following the treatment for Hodgkin’s lymphoma (ABVD regimen, four cycles and AVD regimen, four cycles). A thorough clinical assessment, including actigraphy, melatonin profiles and polysomnography led to the diagnosis of non-24-hour sleep-wake disorders (N24HSWD) with a free-running rhythm of tau = 25.27 h. A therapeutic intervention with bright light therapy (30 min, 10,000 lux) in the morning and melatonin administration (0.5–0.75 mg) in the evening failed to entrain the free-running rhythm, although a longer treatment duration and more intense therapy

  17. Accurate heart rate estimation from camera recording via MUSIC algorithm.

    PubMed

    Fouladi, Seyyed Hamed; Balasingham, Ilangko; Ramstad, Tor Audun; Kansanen, Kimmo

    2015-01-01

    In this paper, we propose an algorithm to extract heart rate frequency from video camera using the Multiple SIgnal Classification (MUSIC) algorithm. This leads to improved accuracy of the estimated heart rate frequency in cases the performance is limited by the number of samples and frame rate. Monitoring vital signs remotely can be exploited for both non-contact physiological and psychological diagnosis. The color variation recorded by ordinary cameras is used for heart rate monitoring. The orthogonality between signal space and noise space is used to find more accurate heart rate frequency in comparison with traditional methods. It is shown via experimental results that the limitation of previous methods can be overcome by using subspace methods. PMID:26738015

  18. Selective Heart Rate Reduction With Ivabradine Increases Central Blood Pressure in Stable Coronary Artery Disease.

    PubMed

    Rimoldi, Stefano F; Messerli, Franz H; Cerny, David; Gloekler, Steffen; Traupe, Tobias; Laurent, Stéphane; Seiler, Christian

    2016-06-01

    Heart rate (HR) lowering by β-blockade was shown to be beneficial after myocardial infarction. In contrast, HR lowering with ivabradine was found to confer no benefits in 2 prospective randomized trials in patients with coronary artery disease. We hypothesized that this inefficacy could be in part related to ivabradine's effect on central (aortic) pressure. Our study included 46 patients with chronic stable coronary artery disease who were randomly allocated to placebo (n=23) or ivabradine (n=23) in a single-blinded fashion for 6 months. Concomitant baseline medication was continued unchanged throughout the study except for β-blockers, which were stopped during the study period. Central blood pressure and stroke volume were measured directly by left heart catheterization at baseline and after 6 months. For the determination of resting HR at baseline and at follow-up, 24-hour ECG monitoring was performed. Patients on ivabradine showed an increase of 11 mm Hg in central systolic pressure from 129±22 mm Hg to 140±26 mm Hg (P=0.02) and in stroke volume by 86±21.8 to 107.2±30.0 mL (P=0.002). In the placebo group, central systolic pressure and stroke volume remained unchanged. Estimates of myocardial oxygen consumption (HR×systolic pressure and time-tension index) remained unchanged with ivabradine.The decrease in HR from baseline to follow-up correlated with the concomitant increase in central systolic pressure (r=-0.41, P=0.009) and in stroke volume (r=-0.61, P<0.001). In conclusion, the decrease in HR with ivabradine was associated with an increase in central systolic pressure, which may have antagonized possible benefits of HR lowering in coronary artery disease patients. CLINICAL TRIALSURL: http://www.clinicaltrials.gov. Unique identifier NCT01039389. PMID:27091900

  19. A comparison between heart rate and heart rate variability as indicators of cardiac health and fitness.

    PubMed

    Grant, Catharina C; Murray, Carien; Janse van Rensburg, Dina C; Fletcher, Lizelle

    2013-01-01

    Quantification of cardiac autonomic activity and control via heart rate (HR) and heart rate variability (HRV) is known to provide prognostic information in clinical populations. Issues with regard to standardization and interpretation of HRV data make the use of the more easily accessible HR on its own as an indicator of autonomic cardiac control very appealing. The aim of this study was to investigate the strength of associations between an important cardio vascular health metric such as VO2max and the following: HR, HRV indicators, and HR normalized HRV indicators. A cross sectional descriptive study was done including 145 healthy volunteers aged between 18 and 22 years. HRV was quantified by time domain, frequency domain and Poincaré plot analysis. Indirect VO2max was determined using the Multistage Coopers test. The Pearson correlation coefficient was calculated to quantify the strength of the associations. Both simple linear and multiple stepwise regressions were performed to be able to discriminate between the role of the individual indicators as well as their combined association with VO2max. Only HR, RR interval, and pNN50 showed significant (p < 0.01, p < 0.01, and p = 0.03) correlations with VO2max. Stepwise multiple regression indicated that, when combining all HRV indicators the most important predictor of cardio vascular fitness as represented by VO2max, is HR. HR explains 17% of the variation, while the inclusion of HF (high frequency HRV indicator) added only an additional 3.1% to the coefficient of determination. Results also showed when testing the normalized indicators, HR explained of the largest percentage of the changes in VO2max (16.5%). Thus, HR on its own is the most important predictor of changes in an important cardiac health metric such as VO2max. These results may indicate that during investigation of exercise ability (VO2max) phenomena, quantification of HRV may not add significant value. PMID:24312058

  20. Interaction Between Heart Rate Variability and Heart Rate in Pediatric Population

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Pawłowski, Mariusz; Werner, Bożena; Dąbrowski, Marek J.

    2015-01-01

    Background: Heart rate variability (HRV) is primarily heart rate (HR) dependent, and therefore, different HR may exert different impact on HRV. The objectives of the study were to evaluate the effect of HR on HRV in children and to determine whether HRV indices normalized to HR are sex- and age-related. Methods: Short-term ECG recordings were performed in 346 healthy children. Standard time and frequency domain HRV parameters and HR were analyzed in four age subgroups (6–7, 8–9, 10–11, and 12–13 years old). To investigate the HR impact on HRV, standard HRV parameters were normalized to prevailing HR. Results: Standard HRV measures did not differ between age subgroups, however, HR significantly decreased with subjects age and turned out to be the strongest determinant of HRV. The normalization of HRV to prevailing HR allowed to show that sex-related differences in standard HRV resulted from differences in HR between boys and girls. The normalized HRV significantly decreased with age—before the normalization this effect was masked by age-related HR alterations. Conclusions: HR significantly impacts HRV in pediatric population and turns out to be the strongest determinant of all standard HRV indices. The differences in standard HRV between boys and girls result from differences in their HR. The normalized HRV is decreasing with age in healthy children and it is accompanied by the reduction of HR—as a net result, the standard HRV is constant in children at different ages. This may reflect the maturation of the autonomic nervous system. PMID:26733878

  1. What and how much do we eat? 24-hour dietary recall method.

    PubMed

    Salvador Castell, Gemma; Serra-Majem, Lluis; Ribas-Barba, Lourdes

    2015-02-26

    Diet, along with lifestyle factors, is an important determinant of the health status of an individual and of a community. Dietary assessment at the population level provides us with key information on the frequency and distribution of possible inadequate diets and/or nutritional status. It is also useful as input into the elaboration of food and nutrition policies aiming to improve dietary habits and the health status of a community. This article reviews the characteristics, advantages and limitations of the 24-hour dietary recall method (24hDR), which is one of the most widely used tools in nutrition epidemiology to identify food, energy and nutrient intake in national nutrition surveys, cross-sectional studies, clinical trials and cohort studies as well as in the evaluation of individual dietary intake and Total Diet assessment. To reduce the key factors associated with bias, the importance of previously trained interviewers is highlighted, as well as the role of support materials and the contribution of novel technologies.

  2. Sudden cardiac arrest risk stratification based on 24-hour Holter ECG statistics.

    PubMed

    Kasahara, Keisuke; Shiobara, Masahito; Nakamura, Saya; Yamashiro, Koichiro; Yana, Kazuo; Ono, Takuya

    2015-08-01

    This study examined the feasibility of using indices obtained from a long term Holter ECG record for sudden cardiac arrest (SCA) risk stratification. The ndices tested were the QT-RR interval co-variability and the alternans ratio percentile (ARP(θ)) which is defined as the θ(th) percentile of alternans ratios over a 24 hour period. The QT-RR interval co-variabilities are evaluated by the serial correlation coefficient between QT and RR trend sequences (QTRC). Previously reported Kalman filter technique and a simple smoothing spline method for the trend estimation are compared. Parameter θ in the alternans ratio percentile index was optimized to achieve the best classification accuracy. These indices were estimated from 26 cardiovascular outpatients for Holter ECG record. Patients were classified into high and low risk groups according to their clinical diagnosis, and the obtained indices were compared with those of 25 control subjects. A risk stratification using the two indices QTRC and ARP(θ) yielded an average sensitivity of 0.812 and a specificity of 0.925. The sensitivities and specificities of all three categories exceeded 0.8 except for the sensitivity to detect the high-risk patient group. Other short-term ECG parameters may need to be incorporated in order to improve the sensitivity.

  3. 24 Hours in the Life of HIV-1 in a T Cell Line

    PubMed Central

    Mohammadi, Pejman; Desfarges, Sébastien; Bartha, István; Joos, Beda; Zangger, Nadine; Muñoz, Miguel; Günthard, Huldrych F.; Beerenwinkel, Niko; Telenti, Amalio; Ciuffi, Angela

    2013-01-01

    HIV-1 infects CD4+ T cells and completes its replication cycle in approximately 24 hours. We employed repeated measurements in a standardized cell system and rigorous mathematical modeling to characterize the emergence of the viral replication intermediates and their impact on the cellular transcriptional response with high temporal resolution. We observed 7,991 (73%) of the 10,958 expressed genes to be modulated in concordance with key steps of viral replication. Fifty-two percent of the overall variability in the host transcriptome was explained by linear regression on the viral life cycle. This profound perturbation of cellular physiology was investigated in the light of several regulatory mechanisms, including transcription factors, miRNAs, host-pathogen interaction, and proviral integration. Key features were validated in primary CD4+ T cells, and with viral constructs using alternative entry strategies. We propose a model of early massive cellular shutdown and progressive upregulation of the cellular machinery to complete the viral life cycle. PMID:23382686

  4. Age and individual sleep characteristics affect cognitive performance in anesthesiology residents after a 24-hour shift.

    PubMed

    Tadinac, Meri; Sekulić, Ante; Hromatko, Ivana; Mazul-Sunko, Branka; Ivancić, Romina

    2014-03-01

    Previous research has shown that both shift work and sleep deprivation have an adverse influence on various aspects of human cognitive performance. The aim of this study was to explore changes in cognitive functioning and subjective sleepiness of anesthesiology residents after a 24-hour shift. Twenty-six anesthesiology residents completed a set of psychological instruments at the beginning and at the end of the shift, as well as a questionnaire regarding information about the shift, Stanford Sleepiness Scale, and Circadian Type Questionnaire. There was a significant decline in cognitive performance measured by the Auditory Verbal Learning Test after the shift. The effect was stronger in older participants and in those with high scores on rigidity of sleep scale and low scores on the ability to overcome sleepiness scale. There were no differences in the digits forward test (a measure of concentration), while digits backward test (a measure of working memory) even showed an improved performance after the shift. Although participants reported being significantly sleepier after the shift, the subjective sleepiness did not correlate with any of the objective measures of cognitive performance. In conclusion, the performance in short tasks involving concentration and working memory was not impaired, while performance in long-term and monotone tasks declined after sleep deprivation, and the magnitude of this decline depended on the specific individual characteristics of sleep and on age Surprisingly, age seemed to have an important impact on cognitive functions after shift work even in the relatively age-homogeneous population of young anesthesiology residents.

  5. Obtaining liver tridimensional scaffold through the decellularization of rabbit whole liver in 24 hours

    NASA Astrophysics Data System (ADS)

    Federico, Schliamser; Ayelen, Rinaldi; Romina, Comin; Alba Nelly, Borchert; Adrian, Nari Gustavo; Alicia, Salvatierra Nancy; Mariana Paula, Cid

    2016-04-01

    In the present work, we development a new protocol for liver decellularization in which the hole decellularization was reached over 24 h. Introduction: the availability of transplantable livers is not sufficient to fulfill the current demand for grafts, with the search for therapeutic alternatives having generated different lines of research, one of which is the use of decellularized three-dimensional biological matrices and subsequent cell seeding to obtain a functional organ. Objective: to produce a decellularization protocol from rabbit liver to generate a three-dimensional matrixin which the time period involved didn't pass 24 h. Methods: The decellularization is obtained through the use of water and SDS (0,1-0,3 %), after freezing at -80 degrees, is the best alternative of different physical and/or chemical mechanisms to break down organ cells and leave only the extracellular matriz. After 24 h of retrograde perfusion, a decellularized translucent matrix was generated. To evaluate if the decellularization protocol was successful, with the extracellular matrix being preserved, we carried out histological (light microscopy) and biochemical (DNA quantification) studies. Results: the decellularization process was verified by macroscopic observation of the organ using microscopic observation corroborated the macroscopic results, with the hematoxylin-eosin and Masson staining showing no cells or nuclear material. In addition, the DNA quantification was less than 10% in the decellularized liver compared to control. Finally,the time taken to develop the decellularization protocol was less than 24 hours.

  6. Electrodes for 24 hours pH monitoring--a comparative study.

    PubMed Central

    McLauchlan, G; Rawlings, J M; Lucas, M L; McCloy, R F; Crean, G P; McColl, K E

    1987-01-01

    Three pH electrodes in clinical use were examined--(1) antimony electrode with remote reference electrode (Synectics 0011), (2) glass electrode with remote reference electrode (Microelectrodes Inc. MI 506) and (3) combined glass electrode with integral reference electrode (Radiometer GK2801C). In vitro studies showed that both glass electrodes were similar and superior to the antimony electrode with respect to response time, drift, and sensitivity. The effect of the siting of the reference electrode on the recorded pH was examined in five human volunteers. The pH reading using a remote skin reference electrode was higher by a mean of 0.3 pH units (range 0.0-0.6) in the stomach, lower by 0.65 pH units (0.5-0.8) in the duodenum and lower by 0.3 pH units (0.0-0.6) in the oesophagus than that simultaneously obtained with an intraluminal reference electrode. Buccal reference electrodes gave similar readings to skin. Combined reference and glass pH electrodes are recommended for 24-hour ambulatory pH monitoring. Images Fig. 1 PMID:3666560

  7. Depressive Symptoms and 24-Hour Ambulatory Blood Pressure in Africans: The SABPA Study

    PubMed Central

    Hamer, Mark; Frasure-Smith, Nancy; Lespérance, François; Harvey, Brian H.; Malan, Nico T.; Malan, Leoné

    2012-01-01

    Disturbances in circadian rhythm might play a central role in the neurobiology of depression. We examined the association between depressive symptoms and 24-hour ambulatory BP in a sample of 405 (197 black and 208 Caucasian) urbanized African teachers aged 25 to 60 yrs (mean 44.6 ± 9.6 yrs). Depressive symptoms were assessed using the self-administered 9-item Patient Health Questionnaire (PHQ-9). After adjusting for age, sex, and ethnicity, participants with severe depressive symptoms (PHQ-9 ≥ 15) had higher odds of hypertension defined from ambulatory BP and/or use of antihypertensive medication (odds ratio = 2.19, 95% CI, 1.00–4.90) in comparison to participants with no symptoms. Compared to Caucasians with no depressive symptoms, those with severe symptoms had blunted nocturnal systolic BP drop of 4.7 mmHg (95% CI, −0.5 to 10.0, P = 0.07). In summary, depressive symptoms were associated with the circadian BP profile in black and Caucasian Africans. PMID:22028954

  8. Importance of all movement behaviors in a 24 hour period for overall health.

    PubMed

    Chaput, Jean-Philippe; Carson, Valerie; Gray, Casey E; Tremblay, Mark S

    2014-12-01

    Physical inactivity and childhood obesity are well-recognized public health concerns that are associated with a range of adverse health outcomes. Historically, the benefits of physical activity (e.g., moderate-to-vigorous physical activity-MVPA) to overall health have dominated discussions and emerging evidence indicates that a broader, more integrated approach is needed to better understand and address current public health crises. Existing guidelines for children and youth around the world only focus on MVPA, and recently sedentary behavior, despite an accumulating body of evidence showing that light-intensity physical activity (LPA) such as walking can provide important health benefits. Furthermore, there is accumulating support for the importance of adequate sleep and that these behaviors moderate the health impact of each other. Ignoring the other components of the movement continuum (i.e., sleep, sedentary time, LPA) while focusing efforts exclusively on MVPA (accounting for <5% of the time in a 24 h period) limits the potential to optimize the health benefits of movement behaviors. In order to address this limitation, experts in Canada are currently developing the world's first Integrated 24 Hour Movement Behaviour Guidelines for Children and Youth to help advance an integrated healthy active living agenda that has the potential to significantly improve the overall health and well-being of children and youth. PMID:25485978

  9. Signal processing methodologies for an acoustic fetal heart rate monitor

    NASA Technical Reports Server (NTRS)

    Pretlow, Robert A., III; Stoughton, John W.

    1992-01-01

    Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively 'trained' in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a series of patients. Comparative data provides favorable indications of the feasibility of the acoustic monitor for clinical use.

  10. SCUBA-dive-related changes in heart rate in children.

    PubMed

    Winkler, Bernd E; Tetzlaff, Kay; Muth, Claus-Martin; Paulat, Klaus; Hebestreit, Helge

    2011-08-01

    The purpose of this study was to monitor heart rate (HR) and rhythm during open water SCUBA dives. Nine children performed 25-min open water SCUBA dives to 8 m depth. Before, during and after these dives, ECG was recorded. Compared with predive heart rate, heart rate declined by -24 ± 8% (range -36%; -15%) during the dive. In some children a further decline in HR was observed within the last minutes of the dive. Older and taller subjects and those with a high initial HR showed a more pronounced decline in HR. Furthermore singular supraventricular and ventricular extrasystoles were observed in some children. Immersion as well as facial and skin cooling presumably account for the initial decline in heart rate. A further drop in HR within the last minutes of the dive might be related to mild hypothermia. Single supraventricular and ventricular extrasystoles might occur in healthy children during dives.

  11. Heart Rate Response and Lactic Acid Concentration in Squash Players.

    ERIC Educational Resources Information Center

    Beaudin, Paula; And Others

    1978-01-01

    It was concluded that playing squash is an activity that results in heart rate responses of sufficient intensity to elicit aerobic training effects without producing high lactic acid concentration in the blood. (MM)

  12. Novel description of the 24-hour circadian rhythms of brachial versus central aortic blood pressure and the impact of blood pressure treatment in a randomized controlled clinical trial: The Ambulatory Central Aortic Pressure (AmCAP) Study.

    PubMed

    Williams, Bryan; Lacy, Peter S; Baschiera, Fabio; Brunel, Patrick; Düsing, Rainer

    2013-06-01

    Elevated brachial blood pressure (BP) is associated with increased cardiovascular risk and predicts morbidity and mortality in humans. Recently, 24-hour ambulatory BP monitoring and assessment of central aortic BP have been introduced to improve BP phenotyping. The Ambulatory Central Aortic Pressure (AmCAP) study combines these approaches and describes, for the first time, the diurnal patterns of simultaneously measured 24-hour ambulatory brachial and central pressures in a prespecified substudy embedded within a clinical trial of BP lowering in patients with hypertension. Twenty-four-hour ambulatory brachial and central pressure measurements were acquired using a tonometer mounted into the articulating strap of a wristwatch-like device (BPro) in 171 participants with hypertension recruited into the ASSERTIVE (AliSkiren Study of profound antihypERtensive efficacy in hyperTensIVE patients) trial. Participants were randomly assigned to BP lowering with either aliskiren 300 mg QD or telmisartan 80 mg QD for 12 weeks. Ambulatory brachial and central BP was measured in all participants both at baseline and at study end. Brachial and central BP both demonstrated typical diurnal patterns with lower pressures at night. However, night time was associated with smaller reductions in central relative to brachial pressure and decreased pulse pressure amplification (P<0.0001 for both). These effects were not modulated after BP lowering and were maintained after adjustment for day and night-time BP and heart rate (P=0.02). This study demonstrates that brachial and central pressure show different diurnal patterns, which are not modulated by BP-lowering therapy, with relatively higher night-time central pressures. These novel data indicate that night-time central BP may provide prognostic importance and warrants further investigation. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00865020. PMID:23630950

  13. Accuracy of Heart Rate Watches: Implications for Weight Management

    PubMed Central

    2016-01-01

    Background Wrist-worn monitors claim to provide accurate measures of heart rate and energy expenditure. People wishing to lose weight use these devices to monitor energy balance, however the accuracy of these devices to measure such parameters has not been established. Aim To determine the accuracy of four wrist-worn devices (Apple Watch, Fitbit Charge HR, Samsung Gear S and Mio Alpha) to measure heart rate and energy expenditure at rest and during exercise. Methods Twenty-two healthy volunteers (50% female; aged 24 ± 5.6 years) completed ~1-hr protocols involving supine and seated rest, walking and running on a treadmill and cycling on an ergometer. Data from the devices collected during the protocol were compared with reference methods: electrocardiography (heart rate) and indirect calorimetry (energy expenditure). Results None of the devices performed significantly better overall, however heart rate was consistently more accurate than energy expenditure across all four devices. Correlations between the devices and reference methods were moderate to strong for heart rate (0.67–0.95 [0.35 to 0.98]) and weak to strong for energy expenditure (0.16–0.86 [-0.25 to 0.95]). All devices underestimated both outcomes compared to reference methods. The percentage error for heart rate was small across the devices (range: 1–9%) but greater for energy expenditure (9–43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices. Conclusion These devices accurately measure heart rate. However, estimates of energy expenditure are poor and would have implications for people using these devices for weight loss. PMID:27232714

  14. Heart rate variability in natural time and 1/f "noise"

    NASA Astrophysics Data System (ADS)

    Sarlis, N. V.; Skordas, E. S.; Varotsos, P. A.

    2009-07-01

    Several studies have shown that heart rate fluctuations exhibit the ubiquitous 1/f behavior which is altered in desease. Furthermore, the analysis of electrocardiograms in natural time reveals that important malfunctions in the complex system of the human heart can be identified. Here, we present a simple evolution model in natural time that exhibits the 1/fa behavior with a close to unity. The results of this model are consistent with a progressive modification of heart rate variability in healthy children and adolescents. The model results in complexity measures that separate healthy dynamics from patients as well as from sudden cardiac death individuals.

  15. 24-hour control of body temperature in rats. I. Integration of behavioral and autonomic effectors.

    PubMed

    Gordon, C J

    1994-07-01

    Some studies suggest that the nocturnal elevation in core temperature (Tc) of the rat is mediated by an elevation in the set point. The role of set point can be assessed if behavioral effectors are measured simultaneously with other thermoregulatory effectors and Tc over a 24-h period. Selected ambient temperature (STa) and motor activity (MA) were measured in rats housed in a temperature gradient system with a 12:12-h photoperiod (lights on 0600 h). Tc and heart rate (HR) were monitored by telemetry. During the light phase, STa, Tc, HR, and MA were relatively stable with values 29.0 degrees C, 37.1 degrees C, 310 beats/min, and 1-2 m/h, respectively. During the light-to-dark transition there were abrupt elevations in Tc, HR, and MA but no change in STa. STa decreased during the dark phase and reached a nadir of 23 degrees C at 0500 h. All variables recovered to basal levels within 3-4 h after the onset of the light phase. Overall, autonomic effectors control the elevation in Tc during the onset of the dark phase while behavioral effectors have little if any role. Behavioral thermoregulation is important in two ways: 1) the selection of cooler Ta values at night to prevent an excess elevation in Tc and 2) a preference for cooler Ta values before the light phase to facilitate the recovery of Tc. PMID:8048648

  16. Digital heart rate measurement based on Atmega16L

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoqing; Feng, Lishuang; Wang, Jiqiang

    2008-02-01

    The photoelectric heart rate meter reported in this paper picks up heart rate signals with a photoelectric cell, converts them into standard TTL pulse signal, and sends them into the input capture interface of a single-chip computer Atmega16L. Its input capture register can capture the Timer/Counter value at a given external (edge triggered) event on the input capture pin (ICP1) of T/C1. The counter number is sent into T/C1's input capture register ICR1 after the voltage of the input capture pin ICP1 jumped according to the program setting. The single-chip computer catches the input pulse signal as some numerical values of Timer/Counter (T/C1) and works out a single heart rate cycle and displays by three seven segment tubes, which are the peripheral equipments of the single-chip computer. ICCAVR integrated compiler is applied to assemble and compile the software programs of the heart rate meter. After the programs compiled successfully, a HEX file is produced and downloaded into the single chip computer by software SLISP. This photoelectric heart rate meter can measure the people heart rate efficiently with measurement range of 10-200 times per minute, precision of +/- 1%, low cost and reliable performance.

  17. 1/f scaling in heart rate requires antagonistic autonomic control

    NASA Astrophysics Data System (ADS)

    Struzik, Zbigniew R.; Hayano, Junichiro; Sakata, Seiichiro; Kwak, Shin; Yamamoto, Yoshiharu

    2004-11-01

    We present systematic evidence for the origins of 1/f -type temporal scaling in human heart rate. The heart rate is regulated by the activity of two branches of the autonomic nervous system: the parasympathetic (PNS) and the sympathetic (SNS) nervous systems. We examine alterations in the scaling property when the balance between PNS and SNS activity is modified, and find that the relative PNS suppression by congestive heart failure results in a substantial increase in the Hurst exponent H towards random-walk scaling 1/f2 and a similar breakdown is observed with relative SNS suppression by primary autonomic failure. These results suggest that 1/f scaling in heart rate requires the intricate balance between the antagonistic activity of PNS and SNS.

  18. Comparison of 24-hour Holter Monitoring with 14-day Novel Adhesive Patch Electrocardiographic Monitoring

    PubMed Central

    Barrett, Paddy M.; Komatireddy, Ravi; Haaser, Sharon; Topol, Sarah; Sheard, Judith; Encinas, Jackie; Fought, Angela J.; Topol, Eric J.

    2013-01-01

    BACKGROUND Cardiac arrhythmias are remarkably common and routinely go undiagnosed because they are often transient and asymptomatic. Effective diagnosis and treatment can substantially reduce the morbidity and mortality associated with cardiac arrhythmias. The Zio Patch (iRhythm Technologies, Inc, San Francisco, Calif) is a novel, single-lead electrocardiographic (ECG), lightweight, Food and Drug Administration–cleared, continuously recording ambulatory adhesive patch monitor suitable for detecting cardiac arrhythmias in patients referred for ambulatory ECG monitoring. METHODS A total of 146 patients referred for evaluation of cardiac arrhythmia underwent simultaneous ambulatory ECG recording with a conventional 24-hour Holter monitor and a 14-day adhesive patch monitor. The primary outcome of the study was to compare the detection arrhythmia events over total wear time for both devices. Arrhythmia events were defined as detection of any 1 of 6 arrhythmias, including supraventricular tachycardia, atrial fibrillation/flutter, pause greater than 3 seconds, atrioventricular block, ventricular tachycardia, or polymorphic ventricular tachycardia/ventricular fibrillation. McNemar’s tests were used to compare the matched pairs of data from the Holter and the adhesive patch monitor. RESULTS Over the total wear time of both devices, the adhesive patch monitor detected 96 arrhythmia events compared with 61 arrhythmia events by the Holter monitor (P < .001). CONCLUSIONS Over the total wear time of both devices, the adhesive patch monitor detected more events than the Holter monitor. Prolonged duration monitoring for detection of arrhythmia events using single-lead, less-obtrusive, adhesive-patch monitoring platforms could replace conventional Holter monitoring in patients referred for ambulatory ECG monitoring. PMID:24384108

  19. Sleep-Disordered Breathing and 24-Hour Blood Pressure Pattern Among Older Adults

    PubMed Central

    White, William B.; Kutner, Michael; Ouslander, Joseph G.; Bliwise, Donald L.

    2009-01-01

    Background To examine the association between sleep-disordered breathing (SDB) and 24-hour blood pressure (BP) pattern among community-dwelling older adults. Methods A convenience sample of 70 community-dwelling older adults, recruited from senior housing, community centers, and learning centers, were admitted to General Clinical Research Center, Emory University Hospital, Atlanta, Ga. Information regarding demographic and clinical history was obtained using questionnaires. Twenty-four–hour BP monitoring in supine position was performed using Spacelabs model 20207. Breathing during sleep was monitored with the use of a modified sleep recording system (Embletta, PDS), which monitors nasal and oral airflow, chest and abdominal movements, and pulse oximetry. Night time–daytime (night-day) BP ratio (average night-time BP divided by daytime BP) was calculated both for systolic and diastolic BPs. Results Sixty-nine participants, mean age 74.9 ± 6.4 years (41 [57%] women), completed the study. The mean apnea-hypopnea index (AHI) was 13 ± 13 per hour of sleep, and 20 participants (29%) had AHI ≥15 per hour of sleep, indicating moderate to severe SDB. Moderate to severe SDB (AHI ≥15 per hour of sleep) was significantly associated with nocturnal hypertension, whereas there was no statistically significant difference in wake-time BP between those with and without moderate to severe SDB. Stepwise multiple regressions showed that AHI independently predicted increased night-day systolic and night-day diastolic BP ratio, even after controlling for nocturia frequency. Conclusions The results indicate increased BP load associated with increased AHI in this group of older adults. This increased BP load may contribute to increased hypertension-related morbidity and disease burden. PMID:19196901

  20. Usability of a smartphone food picture app for assisting 24-hour dietary recall: a pilot study

    PubMed Central

    Pope, Benjamin T.; Bilgiç, Pelin; Orr, Barron J.; Suzuki, Asuka; Kim, Angela Sarah; Merchant, Nirav C.; Roe, Denise J.

    2015-01-01

    BACKGROUND/OBJECTIVES The Recaller app was developed to help individuals record their food intakes. This pilot study evaluated the usability of this new food picture application (app), which operates on a smartphone with an embedded camera and Internet capability. SUBJECTS/METHODS Adults aged 19 to 28 years (23 males and 22 females) were assigned to use the Recaller app on six designated, nonconsecutive days in order to capture an image of each meal and snack before and after eating. The images were automatically time-stamped and uploaded by the app to the Recaller website. A trained nutritionist administered a 24-hour dietary recall interview 1 day after food images were taken. Participants' opinions of the Recaller app and its usability were determined by a follow-up survey. As an evaluation indicator of usability, the number of images taken was analyzed and multivariate Poisson regression used to model the factors determining the number of images sent. RESULTS A total of 3,315 food images were uploaded throughout the study period. The median number of images taken per day was nine for males and 13 for females. The survey showed that the Recaller app was easy to use, and 50% of the participants would consider using the app daily. Predictors of a higher number of images were as follows: greater interval (hours) between the first and last food images sent, weekend, and female. CONCLUSIONS The results of this pilot study provide valuable information for understanding the usability of the Recaller smartphone food picture app as well as other similarly designed apps. This study provides a model for assisting nutrition educators in their collection of food intake information by using tools available on smartphones. This innovative approach has the potential to improve recall of foods eaten and monitoring of dietary intake in nutritional studies. PMID:25861429

  1. Changes of deceleration and acceleration capacity of heart rate in patients with acute hemispheric ischemic stroke

    PubMed Central

    Xu, Yan-Hong; Wang, Xing-De; Yang, Jia-Jun; Zhou, Li; Pan, Yong-Chao

    2016-01-01

    Background and purpose Autonomic dysfunction is common after stroke, which is correlated with unfavorable outcome. Phase-rectified signal averaging is a newly developed technique for assessing cardiac autonomic function, by detecting sympathetic and vagal nerve activity separately through calculating acceleration capacity (AC) and deceleration capacity (DC) of heart rate. In this study, we used this technique for the first time to investigate the cardiac autonomic function of patients with acute hemispheric ischemic stroke. Methods A 24-hour Holter monitoring was performed in 63 patients with first-ever acute ischemic stroke in hemisphere and sinus rhythm, as well as in 50 controls with high risk of stroke. DC, AC, heart rate variability parameters, standard deviation of all normal-to-normal intervals (SDNN), and square root of the mean of the sum of the squares of differences between adjacent normal-to-normal intervals (RMSSD) were calculated. The National Institutes of Health Stroke Scale (NIHSS) was used to assess the severity of stroke. We analyzed the changes of DC, AC, SDNN, and RMSSD and also studied the correlations between these parameters and NIHSS scores. Results The R–R (R wave to R wave on electrocardiogram) intervals, DC, AC, and SDNN in the cerebral infarction group were lower than those in controls (P=0.003, P=0.002, P=0.006, and P=0.043), but the difference of RMSSD and the D-value and ratio between absolute value of AC (|AC|) and DC were not statistically significant compared with those in controls. The DC of the infarction group was significantly correlated with |AC|, SDNN, and RMSSD (r=0.857, r=0.619, and r=0.358; P=0.000, P=0.000, and P=0.004). Correlation analysis also showed that DC, |AC|, and SDNN were negatively correlated with NIHSS scores (r=−0.279, r=−0.266, and r=−0.319; P=0.027, P=0.035, and P=0.011). Conclusion Both DC and AC of heart rate decreased in patients with hemispheric infarction, reflecting a decrease in both vagal

  2. Adaptive beat-to-beat heart rate estimation in ballistocardiograms.

    PubMed

    Brüser, Christoph; Stadlthanner, Kurt; de Waele, Stijn; Leonhardt, Steffen

    2011-09-01

    A ballistocardiograph records the mechanical activity of the heart. We present a novel algorithm for the detection of individual heart beats and beat-to-beat interval lengths in ballistocardiograms (BCGs) from healthy subjects. An automatic training step based on unsupervised learning techniques is used to extract the shape of a single heart beat from the BCG. Using the learned parameters, the occurrence of individual heart beats in the signal is detected. A final refinement step improves the accuracy of the estimated beat-to-beat interval lengths. Compared to many existing algorithms, the new approach offers heart rate estimates on a beat-to-beat basis. The agreement of the proposed algorithm with an ECG reference has been evaluated. A relative beat-to-beat interval error of 1.79% with a coverage of 95.94% was achieved on recordings from 16 subjects.

  3. Non-linear heart rate variability indices in the Frequent Hemodialysis Network trials of chronic hemodialysis patients

    PubMed Central

    Ferrario, Manuela; Raimann, Jochen G.; Larive, Brett; Pierratos, Andreas; Thijssen, Stephan; Rajagopalan, Sanjay; Greene, Tom; Cerutti, Sergio; Beck, Gerald; Chan, Christopher; Kotanko, Peter

    2015-01-01

    Background Non-linear heart rate variability (HRV) indices were hypothesized to correlate with cardiac function, fluid overload and physical performance in hemodialysis patients Methods 24-hour Holter electrocardiograms were recorded in patients enrolled in the Frequent Hemodialysis Network (FHN) Daily Dialysis Trial. Correlations between nonlinear HRV indices and left-ventricular ejection fraction (LVEF), left-ventricular end-diastolic volume (LVEDV), extracellular volume (ECV)/total-body water (TBW) ratio, the SF-36 Physical Health Composite (PHC) and Physical Functioning scores (PF) were tested. Results We studied 210 subjects [average age 49.8±13.5 years, 62% males, 42% diabetics]. In non-diabetic patients, MSE SampEn and MSE ApEn correlated positively with LVEF, PF, PH, and inversely with LVEDV and ECV/TBW. SPS correlated positively with ECV/TBW (r=0.27). Irregularity measures (MSE ApEn, MSE SampEn) correlated positively with LVEDV (r=0.19 and 0.20). Conclusion Nonlinear HRV indices indicated an association between a deteriorated heart rate regulatory system and impaired cardiac function, fluid accumulation and poor physical condition. PMID:26159747

  4. Assessing positive emotional states in dogs using heart rate and heart rate variability.

    PubMed

    Zupan, Manja; Buskas, Julia; Altimiras, Jordi; Keeling, Linda J

    2016-03-01

    Since most animal species have been recognized as sentient beings, emotional state may be a good indicator of welfare in animals. The goal of this study was to manipulate the environment of nine beagle research dogs to highlight physiological responses indicative of different emotional experiences. Stimuli were selected to be a more or a less positive food (meatball or food pellet) or social reward (familiar person or less familiar person). That all the stimuli were positive and of different reward value was confirmed in a runway motivation test. Dogs were tested individually while standing facing a display theatre where the different stimuli could be shown by lifting a shutter. The dogs approached and remained voluntarily in the test system. They were tested in four sessions (of 20s each) for each of the four stimuli. A test session consisted of four presentation phases (1st exposure to stimulus, post exposure, 2nd exposure, and access to reward). Heart rate (HR) and heart rate variability (HRV) responses were recorded during testing in the experimental room and also when lying resting in a quiet familiar room. A new method of 'stitching' short periods of HRV data together was used in the analysis. When testing different stimuli, no significant differences were observed in HR and LF:HF ratio (relative power in low frequency (LF) and the high-frequency (HF) range), implying that the sympathetic tone was activated similarly for all the stimuli and may suggest that dogs were in a state of positive arousal. A decrease of HF was associated with the meatball stimulus compared to the food pellet and the reward phase (interacting with the person or eating the food) was associated with a decrease in HF and RMSSD (root mean square of successive differences of inter-beat intervals) compared to the preceding phase (looking at the person or food). This suggests that parasympathetic deactivation is associated with a more positive emotional state in the dog. A similar reduction

  5. The Impact of Using Different Methods to Assess Completeness of 24-Hour Urine Collection on Estimating Dietary Sodium.

    PubMed

    Wielgosz, Andreas; Robinson, Christopher; Mao, Yang; Jiang, Ying; Campbell, Norm R C; Muthuri, Stella; Morrison, Howard

    2016-06-01

    The standard for population-based surveillance of dietary sodium intake is 24-hour urine testing; however, this may be affected by incomplete urine collection. The impact of different indirect methods of assessing completeness of collection on estimated sodium ingestion has not been established. The authors enlisted 507 participants from an existing community study in 2009 to collect 24-hour urine samples. Several methods of assessing completeness of urine collection were tested. Mean sodium intake varied between 3648 mg/24 h and 7210 mg/24 h depending on the method used. Excluding urine samples collected for longer or shorter than 24 hours increased the estimated urine sodium excretion, even when corrections for the variation in timed collections were applied. Until an accurate method of indirectly assessing completeness of urine collection is identified, the gold standard of administering para-aminobenzoic acid is recommended. Efforts to ensure participants collect complete urine samples are also warranted.

  6. Executive Functions are not Affected by 24 Hours of Sleep Deprivation: A Color-Word Stroop Task Study

    PubMed Central

    Dixit, Abhinav; Mittal, Tushar

    2015-01-01

    Background: Sleep is an important factor affecting cognitive performance. Sleep deprivation results in fatigue, lack of concentration, confusion and sleepiness along with anxiety, depression and irritability. Sleep deprivation can have serious consequences in professions like armed forces and medicine where quick decisions and actions need to be taken. Color-Word Stroop task is one of the reliable tests to assess attention and it analyzes the processing of information in two dimensions i.e., reading of words and naming of colour. The evidence regarding the effect of sleep deprivation on Stroop interference is conflicting. The present study evaluated the effect of 24 hours of sleep deprivation on reaction time and interference in Stroop task. Materials and Methods: The present study was done on 30 healthy male medical student volunteers in the age group of 18-25 years after taking their consent and clearance from Institute Ethics Committee. Recordings of Stroop task were at three times: baseline (between 7-9 am), after 12 hours (7-9 pm) and after 24 hours (7-9 am, next day). The subjects were allowed to perform normal daily activities. Results: The study revealed a significant increase in reaction time after 24 hours of sleep deprivation in comparison to baseline and after 12 hours of sleep deprivation. There was no significant change in interference and facilitation after sleep deprivation in comparison to baseline. The number of errors also did not show any significant change after sleep deprivation. Conclusion: The study indicated that there was slowing of responses without change in executive functions after 24 hours of sleep deprivation. It is probable that 24 hours of sleep deprivation does not bring about change in areas of brain affecting executive functions in healthy individuals who have normal sleep cycle. The present study indicated that in professions like armed forces and medicine working 24 hours at a stretch can lead to decrease in motor responses

  7. Sex differences in 24-hour ultra-marathon performance - A retrospective data analysis from 1977 to 2012

    PubMed Central

    Peter, Laura; Rüst, Christoph Alexander; Knechtle, Beat; Rosemann, Thomas; Lepers, Romuald

    2014-01-01

    OBJECTIVES: This study examined the changes in running performance and the sex differences between women and men in 24-hour ultra-marathons held worldwide from 1977 to 2012. METHOD: Changes in running speed and ages of the fastest 24-hour ultra-marathoners were determined using single- and multi-level regression analyses. RESULTS: From 1977 to 2012, the sex differences in 24-hour ultra-marathon performance were 4.6±0.5% for all women and men, 13.3% for the annual fastest finishers, 12.9±0.8% for the top 10 and 12.2±0.4% for the top 100 finishers. Over time, the sex differences decreased for the annual fastest finishers to 17%, for the annual 10 fastest finishers to 11.3±2.2% and for the annual 100 fastest finishers to 14.2±1.8%. For the annual fastest men, the age of peak running speed increased from 23 years (1977) to 53 years (2012). For the annual 10 and 100 fastest men, the ages of peak running speed were unchanged at 40.9±2.5 and 44.4±1.1 years, respectively. For women, the ages of the annual fastest, the annual 10 fastest and the annual 100 fastest remained unchanged at 43.0±6.1, 43.2±2.6 and 43.8±0.8 years, respectively. CONCLUSION: The gap between the annual top, annual top 10 and annual top 100 female and male 24-hour ultra-marathoners decreased over the last 35 years; however, it seems unlikely that women will outrun men in 24-hour ultra-marathons in the near future. The fastest 24-hour ultra-marathoners worldwide achieved their peak performance at the age of master athletes (>35 years). PMID:24473558

  8. Transfer of heart rate feedback training to reduce heart rate response to laboratory tasks.

    PubMed

    Goodie, Jeffrey L; Larkin, Kevin T

    2006-09-01

    To examine whether transfer of heart rate (HR) feedback training to tasks not used during training could be improved by using multiple tasks during training, a modified multiple baseline across tasks, single subject design study was conducted using six high HR-reactive young adults. Participants received HR feedback training during the presentation of a videogame, and transfer of training was assessed to a mental arithmetic challenge and handgrip task. Transfer of training was next assessed following training with the mental arithmetic challenge and handgrip task. HR responses to each training task with no HR feedback were assessed during a pre-treatment session, an immediate post-training period following training on each task, a short delay (1-2 days) post-training session, and a long delay (1-2 weeks) post-training session. HR response to a novel speech task was assessed at pre-treatment and during short delay and long delay post-training sessions. Results revealed that participants reduced HR during training and generally maintained this reduction in HR during the immediate post-training assessment when HR feedback was not present. Participants were not able to reduce HR responses to tasks during short delay and long delay post-training sessions, and they were unable to transfer HR reduction skills to the speech task. Transfer of HR feedback training to new tasks was limited in nature and efforts to train across multiple stressors did not appear to improve transfer of training.

  9. Multiscale Entropy of the Heart Rate Variability for the Prediction of an Ischemic Stroke in Patients with Permanent Atrial Fibrillation

    PubMed Central

    Hayano, Junichiro; Yamamoto, Yoshiharu; Inamasu, Joji; Yamamoto, Mayumi; Ichikawa, Tomohide; Sobue, Yoshihiro; Harada, Masehide; Ozaki, Yukio

    2015-01-01

    Background Atrial fibrillation (AF) is a significant risk factor for ischemic strokes, and making a robust risk stratification scheme would be important. Few studies have examined whether nonlinear dynamics of the heart rate could predict ischemic strokes in AF. We examined whether a novel complexity measurement of the heart rate variability called multiscale entropy (MSE) was a useful risk stratification measure of ischemic strokes in patients with permanent AF. Methods and Results We examined 173 consecutive patients (age 69±11 years) with permanent AF who underwent 24-hour Holter electrocardiography from April 2005 to December 2006. We assessed several frequency ranges of the MSE and CHA2DS2-VASc score (1 point for congestive heart failure, hypertension, diabetes, vascular disease, an age 65 to 74 years, and a female sex and 2 points for an age≥75 years and a stroke or transient ischemic attack). We found 22 (13%) incident ischemic strokes during a mean follow up of 3.8-years. The average value of the MSE in the very-low frequency subrange (90–300 s, MeanEnVLF2) was significantly higher in patients who developed ischemic strokes than in those who did not (0.68±0.15 vs. 0.60±0.14, P<0.01). There was no significant difference in the C-statistic between the CHA2DS2-VASc score and MeanEnVLF2 (0.56; 95% confidence interval, 0.43–0.69 vs. 0.66; 95% confidence interval, 0.53–0.79). After an adjustment for the age, CHA2DS2-VASc score, and antithrombotic agent, a Cox hazard regression model revealed that the MeanEnVLF2 was an independent predictor of an ischemic stroke (hazard ratio per 1-SD increment, 1.80; 95% confidence interval, 1.17–2.07, P<0.01). Conclusion The MeanEnVLF2 in 24-hour Holter electrocardiography is a useful risk stratification measure of ischemic strokes during the long-term follow-up in patients with permanent AF. PMID:26325058

  10. The Association between Noise, Cortisol and Heart Rate in a Small-Scale Gold Mining Community-A Pilot Study.

    PubMed

    Green, Allyson; Jones, Andrew D; Sun, Kan; Neitzel, Richard L

    2015-08-01

    We performed a cross-sectional pilot study on salivary cortisol, heart rate, and personal noise exposures in a small-scale gold mining village in northeastern Ghana in 2013. Cortisol level changes between morning and evening among participants showed a relatively low decline in cortisol through the day (-1.44 ± 4.27 nmol/L, n = 18), a pattern consistent with chronic stress. A multiple linear regression, adjusting for age, sex, smoking status, and time between samples indicated a significant increase of 0.25 nmol/L cortisol from afternoon to evening per 1 dBA increase in equivalent continuous noise exposure (Leq) over that period (95% CI: 0.08-0.42, Adj R(2) = 0.502, n = 17). A mixed effect linear regression model adjusting for age and sex indicated a significant increase of 0.29 heart beats per minute (BPM) for every 1 dB increase in Leq. Using standard deviations (SDs) as measures of variation, and adjusting for age and sex over the sampling period, we found that a 1 dBA increase in noise variation over time (Leq SD) was associated with a 0.5 BPM increase in heart rate SD (95% CI: 0.04--0.9, Adj. R(2) = 0.229, n = 16). Noise levels were consistently high, with 24-hour average Leq exposures ranging from 56.9 to 92.0 dBA, with a mean daily Leq of 82.2 ± 7.3 dBA (mean monitoring duration 22.1 ± 1.9 hours, n = 22). Ninety-five percent of participants had 24-hour average Leq noise levels over the 70 dBA World health Organization (WHO) guideline level for prevention of hearing loss. These findings suggest that small-scale mining communities may face multiple, potentially additive health risks that are not yet well documented, including hearing loss and cardiovascular effects of stress and noise.

  11. Quantification of fetal heart rate regularity using symbolic dynamics

    NASA Astrophysics Data System (ADS)

    van Leeuwen, P.; Cysarz, D.; Lange, S.; Geue, D.; Groenemeyer, D.

    2007-03-01

    Fetal heart rate complexity was examined on the basis of RR interval time series obtained in the second and third trimester of pregnancy. In each fetal RR interval time series, short term beat-to-beat heart rate changes were coded in 8bit binary sequences. Redundancies of the 28 different binary patterns were reduced by two different procedures. The complexity of these sequences was quantified using the approximate entropy (ApEn), resulting in discrete ApEn values which were used for classifying the sequences into 17 pattern sets. Also, the sequences were grouped into 20 pattern classes with respect to identity after rotation or inversion of the binary value. There was a specific, nonuniform distribution of the sequences in the pattern sets and this differed from the distribution found in surrogate data. In the course of gestation, the number of sequences increased in seven pattern sets, decreased in four and remained unchanged in six. Sequences that occurred less often over time, both regular and irregular, were characterized by patterns reflecting frequent beat-to-beat reversals in heart rate. They were also predominant in the surrogate data, suggesting that these patterns are associated with stochastic heart beat trains. Sequences that occurred more frequently over time were relatively rare in the surrogate data. Some of these sequences had a high degree of regularity and corresponded to prolonged heart rate accelerations or decelerations which may be associated with directed fetal activity or movement or baroreflex activity. Application of the pattern classes revealed that those sequences with a high degree of irregularity correspond to heart rate patterns resulting from complex physiological activity such as fetal breathing movements. The results suggest that the development of the autonomic nervous system and the emergence of fetal behavioral states lead to increases in not only irregular but also regular heart rate patterns. Using symbolic dynamics to

  12. [Analysis of scalp potential activity and heart rate variability during volitional control of heart beat].

    PubMed

    Yu, Xiao-Lin; Zhang, Jian-Bao; Wang, Jue

    2009-07-01

    In the study the changes of scalp potential and cardiac autonomic nervous system during volitional control of heart beat are explored with the wavelet packet parameters and approximate entropy (ApEn) of Electroencephalogram (EEG) and heart rate variability. The results show that volition can control heart beat and the changes of brain activity are earlier than that of autonomic activity. But its control of heart beat is very different from the motor nervous system because different cortical positions are respectively concerned during the quick and slow control of heart beat. The pre-central areas of brain are correlated with parasympathetic activity by which HR is controlled to slow down. The post-central areas of brain are correlated with sympathetic activity by which HR is controlled to accelerate.

  13. Circadian (about 24-hour) variation in malondialdehyde content and catalase activity of mouse erythrocytes.

    PubMed

    Sani, Mamane; Sebai, Hichem; Ghanem-Boughanmi, Néziha; Boughattas, Naceur A; Ben-Attia, Mossadok

    2015-01-01

    Lipid peroxidation is a part of normal metabolism that may cause biological molecule damage leading to the formation of several specific metabolites that include aldehydes of variable chains, such as malondialdehyde (MDA). These biological effects are controlled in vivo by a wide spectrum of enzymatic and non-enzymatic defense mechanisms among which catalase (CAT) is considered as an important regulator of oxidative stress. The present study aimed to investigate the possible relationship between the temporal patterns of the formation of MDA and the activity of CAT in the erythrocytes of mice. Twenty-four-hour studies were performed on male Swiss albino mice, 12 weeks old, synchronized to a 12:12 light: dark cycle for 3 weeks. Different and comparable groups of animals (n = 10) were sacrificed at an interval of 4 hours (1, 5, 9, 13, 17, and 21 hours after light onset (HALO)). The levels of erythrocyte MDA concentration and CAT activity both significantly (analysis of variance: F = 6.4, P < 0.002) varied according to the time of sampling under non-stressed conditions. The characteristics of the waveform describing the temporal patterns differed between the two studied variables, e.g. MDA content showing one peak (≅21 HALO) and CAT activity showing three peaks (≅9, 17, and 21 HALO). Cosinor analysis revealed a significant (adjusted Cosinor: P ≤ 0.018) circadian (τ ≅ 24 hours) rhythm in MDA level and no statistically significant rhythmicity in CAT activity. The differences and the absence of correlation between the curve patterns of erythrocyte MDA content and CAT activity under physiological conditions are hypothesized to explain that variation in lipid peroxidation may depend on several factors. Moreover, the identification of peak/trough levels of MDA accumulation in erythrocytes may reflect the degree of oxidative stress in these blood cells. In addition, the observed significant time-of-day effect suggests that, in both clinical and scientific

  14. Characterisation of sleep in intensive care using 24-hour polysomnography: an observational study

    PubMed Central

    2013-01-01

    Introduction Many intensive care patients experience sleep disruption potentially related to noise, light and treatment interventions. The purpose of this study was to characterise, in terms of quantity and quality, the sleep of intensive care patients, taking into account the impact of environmental factors. Methods This observational study was conducted in the adult ICU of a tertiary referral hospital in Australia, enrolling 57 patients. Polysomnography (PSG) was performed over a 24-hour period to assess the quantity (total sleep time: hh:mm) and quality (percentage per stage, duration of sleep episode) of patients' sleep while in ICU. Rechtschaffen and Kales criteria were used to categorise sleep. Interrater checks were performed. Sound pressure and illuminance levels and care events were simultaneously recorded. Patients reported on their sleep quality in ICU using the Richards Campbell Sleep Questionnaire and the Sleep in Intensive Care Questionnaire. Data were summarised using frequencies and proportions or measures of central tendency and dispersion as appropriate and Cohen's Kappa statistic was used for interrater reliability of the sleep data analysis. Results Patients' median total sleep time was 05:00 (IQR: 02:52 to 07:14). The majority of sleep was stage 1 and 2 (medians: 19 and 73%) with scant slow wave and REM sleep. The median duration of sleep without waking was 00:03. Sound levels were high (mean Leq 53.95 dB(A) during the day and 50.20 dB(A) at night) and illuminance levels were appropriate at night (median <2 lux) but low during the day (median: 74.20 lux). There was a median 1.7 care events/h. Patients' mean self-reported sleep quality was poor. Interrater reliability of sleep staging was highest for slow wave sleep and lowest for stage 1 sleep. Conclusions The quantity and quality of sleep in intensive care patients are poor and may be related to noise, critical illness itself and treatment events that disturb sleep. The study highlights the

  15. Analysis of 24-Hour Ambulatory Blood Pressure Monitoring in Children With Obstructive Sleep Apnea

    PubMed Central

    Kang, Kun-Tai; Chiu, Shuenn-Nan; Weng, Wen-Chin; Lee, Pei-Lin; Hsu, Wei-Chung

    2015-01-01

    Abstract In the present study, we aimed to verify associations between ambulatory blood pressure (ABP) and pediatric obstructive sleep apnea (OSA) in a hospital-based population. This was a cross-sectional observational study on children aged 4 to 16 years with OSA-related symptoms from a tertiary referral medical center. All children received overnight polysomnography and 24-hour recording of ABP. Severity of the disease was classified as primary snoring (apnea-hypopnea index, AHI <1), mild OSA (AHI 1–5), and moderate-to-severe OSA (AHI >5). For 195 children enrolled in this study (mean age, 7.8 ± 3.4 years; 69% boy), ABP increased as severity of OSA increased. During daytime, children with moderate-to-severe OSA had significantly higher systolic blood pressure (BP) (117.0 ± 12.7 vs 110.5 ± 9.3 mmHg), mean arterial pressure (MAP) (85.6 ± 8.1 vs 81.6 ± 6.8 mmHg), and diastolic BP load (12.0 ± 9.6 vs 8.4 ± 10.9 mmHg) compared with children with primary snoring. During nighttime, children with moderate-to-severe OSA had significantly higher systolic BP (108.6 ± 15.0 vs 100.0 ± 9.4 mmHg), MAP (75.9 ± 9.6 vs 71.1 ± 7.0 mmHg), systolic BP load (44.0 ± 32.6 vs 26.8 ± 24.5 mmHg), systolic BP index (0.5 ± 13.1 vs −6.8 ± 8.5 mmHg), and higher prevalence of systolic hypertension (47.6% vs 14.7 %) compared with children with primary snoring. Multiple linear regression analyses revealed an independent association between AHI and nighttime systolic BP and MAP after adjusting for adiposity variables. This large hospital-based study showed that children with moderate-to-severe OSA had a higher ABP compared with children who were primary snorers. As elevated BP in childhood predicts future cardiovascular risks, children with severe OSA should be treated properly to prevent further adverse cardiovascular outcomes. PMID:26448004

  16. 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

  17. 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.

  18. Heart rate measurement based on face video sequence

    NASA Astrophysics Data System (ADS)

    Xu, Fang; Zhou, Qin-Wu; Wu, Peng; Chen, Xing; Yang, Xiaofeng; Yan, Hong-jian

    2015-03-01

    This paper proposes a new non-contact heart rate measurement method based on photoplethysmography (PPG) theory. With this method we can measure heart rate remotely with a camera and ambient light. We collected video sequences of subjects, and detected remote PPG signals through video sequences. Remote PPG signals were analyzed with two methods, Blind Source Separation Technology (BSST) and Cross Spectral Power Technology (CSPT). BSST is a commonly used method, and CSPT is used for the first time in the study of remote PPG signals in this paper. Both of the methods can acquire heart rate, but compared with BSST, CSPT has clearer physical meaning, and the computational complexity of CSPT is lower than that of BSST. Our work shows that heart rates detected by CSPT method have good consistency with the heart rates measured by a finger clip oximeter. With good accuracy and low computational complexity, the CSPT method has a good prospect for the application in the field of home medical devices and mobile health devices.

  19. Concurrent validity of the Armour39 heart rate monitor strap.

    PubMed

    Flanagan, Shawn D; Comstock, Brett A; Dupont, William H; Sterczala, Adam R; Looney, Dave P; Dombrowski, Dylan H; McDermott, Danielle M; Bryce, Alexander; Maladouangdock, Jesse; Dunn-Lewis, Courtenay; Luk, Hui-Ying; Szivak, Tunde K; Hooper, David R; Kraemer, William J

    2014-03-01

    New technology offers potential advantages in physically demanding environments where convenience and comfort are important and accurate and reliable data collection is challenging. Nevertheless, it is important to validate the accuracy and reliability of such biological monitoring systems (BMS) before they are adopted. The purpose of this investigation was to assess the concurrent validity of a new heart rate monitor across a range of exercise intensities and with a large and diverse group of male subjects in a large cohort with diverse physical fitness characteristics. Seventy-five men (age, 23 ± 4 years; height, 181 ± 8 cm; body mass, 83 ± 12 kg; estimated V[Combining Dot Above]O2peak, 3.16 ± 0.63 [L·min]) volunteered and completed a graded cycle ergometer exercise protocol while heart rate was continuously monitored before, during, and after exercise with the new device (Armour39) and the gold standard (electrocardiogram). The 2-minute stages included sitting, standing, and cycling with 35 W increments until volitional fatigue. The coefficient of determination between mean heart rate values at each stage was R = 0.99, whereas Pearson correlations (r) at each stage were ≥ 0.99. Heart rates during exercise were typically within 1 beat of each other. The Armour39 BMS, therefore, is an acceptable means for the valid and reliable determination of heart rate under various bodily positions and levels of exertion, including maximal exercise intensity. PMID:23860286

  20. The Use of Heart Rate Monitors in Physical Education

    ERIC Educational Resources Information Center

    Nichols, Randall; Davis, Kathryn L.; McCord, Tim; Schmidt, Dave; Slezak, Alex M.

    2009-01-01

    The ever-rising rate of obesity and the need for increased physical activity for young children is well documented. Data suggests that today's youth are not participating in enough quality health-enhancing physical activity either in or outside of school. Heart rate monitors have been used by adult exercisers for many years to monitor and assess…

  1. Heart rate and heart rate variability in pregnant dairy cows and their fetuses determined by fetomaternal electrocardiography.

    PubMed

    Trenk, Lisa; Kuhl, Juliane; Aurich, Jörg; Aurich, Christine; Nagel, Christina

    2015-11-01

    In this study, fetomaternal electrocardiograms were recorded once weekly in cattle during the last 14 weeks of gestation. From the recorded beat-to-beat (RR) intervals, heart rate and heart rate variability (HRV) variables standard deviation of the RR interval (SDRR) and root mean square of successive RR differences (RMSSD) were calculated. To differentiate between effects of lactation and gestation, pregnant lactating (PL) cows (n = 7) and pregnant nonlactating (PNL) heifers (n = 8) were included. We hypothesized that lactation is associated with stress detectable by HRV analysis. We also followed the hypothesis that heart rate and HRV are influenced by growth and maturation of the fetus toward term. Maternal heart rate changed over time in both groups, and in PL cows, it decreased with drying-off. During the last 5 weeks of gestation, maternal heart rate increased in both groups but was lower in PL cows than in PNL heifers. Maternal HRV did not change over time, but SDRR was significantly higher in PL cows than in PNL heifers, and significant interactions of group × time existed. On the basis of HRV, undisturbed pregnancies are thus no stressor for the dam in cattle. Fetal heart rate decreased from week 14 to week 1 before birth with no difference between groups. Gestational age thus determines heart rate in the bovine fetus. The HRV variables SDRR and RMSSD increased toward the end of gestation in fetuses carried by cows but not in those carried by heifers. The increase in HRV indicates maturation of fetal cardiac regulation which may be overrun by high sympathoadrenal activity in fetuses carried by heifers as suggested by their low HRV. PMID:26279313

  2. Continuous positive airway pressure increases heart rate variability in heart failure patients with obstructive sleep apnoea.

    PubMed

    Gilman, Matthew P; Floras, John S; Usui, Kengo; Kaneko, Yasuyuki; Leung, Richard S T; Bradley, T Douglas

    2008-02-01

    Patients with heart failure or OSA (obstructive sleep apnoea) have reduced HF-HRV (high-frequency heart rate variability), indicating reduced cardiac vagal modulation, a marker of poor prognosis. CPAP (continuous positive airway pressure) abolishes OSA in patients with heart failure, but effects on daytime HF-HRV have not been determined. We hypothesized that, in patients with heart failure, treatment of coexisting OSA by CPAP would increase morning HF-HRV. In 19 patients with heart failure (left ventricular ejection fraction <45%) and OSA (>/=20 apnoeas and hypopnoeas/h of sleep), HF-HRV was quantified before and 1 month after randomization to a control or CPAP-treated group. In the control group (n=7), there were no changes in HF-HRV over the 1 month study during wakefulness in the morning. In the CPAP-treated group (n=12) HF-HRV increased significantly during wakefulness in the morning [from 2.43+/-0.55 to 2.82+/-0.50 log(ms(2)/Hz); P=0.002] due to an increase in transfer function between changes in lung volume and changes in HF-HRV (92.37+/-96.03 to 219.07+/-177.14 ms/l; P=0.01). In conclusion, treatment of coexisting OSA by nocturnal CPAP in patients with heart failure increases HF-HRV during morning wakefulness, indicating improved vagal modulation of heart rate. This may contribute to improved prognosis.

  3. Increased heart rate variability but no effect on blood pressure from 8 weeks of hatha yoga – a pilot study

    PubMed Central

    2013-01-01

    Background Yoga exercises are known to decrease stress and restore autonomic balance. Yet knowledge about the physiological effects of inversion postures is limited. This study aimed to investigate the effects of inversion postures (head below the heart) on blood pressure (BP) and heart rate variability (HRV). Methods Twelve healthy women and men took part in an 8-week yoga program (60 min once a week). BP was measured with an automatic Omron mx3 oscillometric monitoring device and HRV with a Holter 24-hour ECG at baseline and 8 weeks after the intervention. Results There was no significant effect of inversion postures on BP. Nine out of 12 participants showed a significant increase in HRV (p < 0.05) at night (2 hours) on pNN50% (12.7 ± 12.5 to 18.2 ± 13.3). There were no significant changes in other HRV measures such as NN50, LF, HF, LF/HF ratio, LF normalized units (n.u.), HF n.u. and RMSSD. Conclusion Eight weeks of hatha yoga improved HRV significantly which suggests an increased vagal tone and reduced sympathetic activity. PMID:23398959

  4. Neuroanatomical substrates for the volitional regulation of heart rate

    PubMed Central

    Jones, Catherine L.; Minati, Ludovico; Nagai, Yoko; Medford, Nick; Harrison, Neil A.; Gray, Marcus; Ward, Jamie; Critchley, Hugo D.

    2015-01-01

    The control of physiological arousal can assist in the regulation of emotional state. A subset cortical and subcortical brain regions are implicated in autonomic control of bodily arousal during emotional behaviors. Here, we combined human functional neuroimaging with autonomic monitoring to identify neural mechanisms that support the volitional regulation of heart rate, a process that may be assisted by visual feedback. During functional magnetic resonance imaging (fMRI), 15 healthy adults performed an experimental task in which they were prompted voluntarily to increase or decrease cardiovascular arousal (heart rate) during true, false, or absent visual feedback. Participants achieved appropriate changes in heart rate, without significant modulation of respiratory rate, and were overall not influenced by the presence of visual feedback. Increased activity in right amygdala, striatum and brainstem occurred when participants attempted to increase heart rate. In contrast, activation of ventrolateral prefrontal and parietal cortices occurred when attempting to decrease heart rate. Biofeedback enhanced activity within occipito-temporal cortices, but there was no significant interaction with task conditions. Activity in regions including pregenual anterior cingulate and ventral striatum reflected the magnitude of successful task performance, which was negatively related to subclinical anxiety symptoms. Measured changes in respiration correlated with posterior insula activation and heart rate, at a more lenient threshold, change correlated with insula, caudate, and midbrain activity. Our findings highlight a set of brain regions, notably ventrolateral prefrontal cortex, supporting volitional control of cardiovascular arousal. These data are relevant to understanding neural substrates supporting interaction between intentional and interoceptive states related to anxiety, with implications for biofeedback interventions, e.g., real-time fMRI, that target emotional

  5. Neuroanatomical substrates for the volitional regulation of heart rate.

    PubMed

    Jones, Catherine L; Minati, Ludovico; Nagai, Yoko; Medford, Nick; Harrison, Neil A; Gray, Marcus; Ward, Jamie; Critchley, Hugo D

    2015-01-01

    The control of physiological arousal can assist in the regulation of emotional state. A subset cortical and subcortical brain regions are implicated in autonomic control of bodily arousal during emotional behaviors. Here, we combined human functional neuroimaging with autonomic monitoring to identify neural mechanisms that support the volitional regulation of heart rate, a process that may be assisted by visual feedback. During functional magnetic resonance imaging (fMRI), 15 healthy adults performed an experimental task in which they were prompted voluntarily to increase or decrease cardiovascular arousal (heart rate) during true, false, or absent visual feedback. Participants achieved appropriate changes in heart rate, without significant modulation of respiratory rate, and were overall not influenced by the presence of visual feedback. Increased activity in right amygdala, striatum and brainstem occurred when participants attempted to increase heart rate. In contrast, activation of ventrolateral prefrontal and parietal cortices occurred when attempting to decrease heart rate. Biofeedback enhanced activity within occipito-temporal cortices, but there was no significant interaction with task conditions. Activity in regions including pregenual anterior cingulate and ventral striatum reflected the magnitude of successful task performance, which was negatively related to subclinical anxiety symptoms. Measured changes in respiration correlated with posterior insula activation and heart rate, at a more lenient threshold, change correlated with insula, caudate, and midbrain activity. Our findings highlight a set of brain regions, notably ventrolateral prefrontal cortex, supporting volitional control of cardiovascular arousal. These data are relevant to understanding neural substrates supporting interaction between intentional and interoceptive states related to anxiety, with implications for biofeedback interventions, e.g., real-time fMRI, that target emotional

  6. Effects of dietary interventions on 24-hour urine parameters in patients with idiopathic recurrent calcium oxalate stones.

    PubMed

    Kıraç, Mustafa; Küpeli, Bora; Irkilata, Lokman; Gülbahar, Ozlem; Aksakal, Nur; Karaoğlan, Ustünol; Bozkırlı, Ibrahim

    2013-02-01

    The aim of this study is to investigate the effects of dietary factors on 24-hour urine parameters in patients with idiopathic recurrent calcium oxalate stones. A total of 108 of idiopathic recurrent calcium oxalate stones were included in the study. A 24-hour urinalysis was performed and metabolic abnormalities were measured for all of the patients. All of the patients were given specialized diets for their 24-hour urine abnormalities. At the end of first month, the same parameters were examined in another 24-hour urinalysis. Hyperoxaluria, hypernatruria, and hypercalciuria were found in 84 (77%), 43 (39.8%), and 38 (35.5%) of the patients, respectively. The differences between the oxalate, sodium, volume, uric acid, and citrate parameters before and after the dietary intervention were significant (p < 0.05). The calcium parameters were not significantly different before and after the intervention. We found that oxalate, sodium, volume, uric acid, and citrate-but not calcium-abnormalities in patients with recurrent calcium oxalate stones can be corrected by diet. The metabolic profiles of idiopathic calcium oxalate stone patients should be evaluated and the appropriate dietary interventions should be implemented to decrease stone recurrence.

  7. Self-Renewal and Differentiation Capacity of Urine-Derived Stem Cells after Urine Preservation for 24 Hours

    PubMed Central

    Shi, Yingai; Bharadwaj, Shantaram; Leng, Xiaoyan; Zhou, Xiaobo; Liu, Hong; Atala, Anthony; Zhang, Yuanyuan

    2013-01-01

    Despite successful approaches to preserve organs, tissues, and isolated cells, the maintenance of stem cell viability and function in body fluids during storage for cell distribution and transportation remains unexplored. The aim of this study was to characterize urine-derived stem cells (USCs) after optimal preservation of urine specimens for up to 24 hours. A total of 415 urine specimens were collected from 12 healthy men (age range 20–54 years old). About 6×104 cells shed off from the urinary tract system in 24 hours. At least 100 USC clones were obtained from the stored urine specimens after 24 hours and maintained similar biological features to fresh USCs. The stored USCs had a “rice grain” shape in primary culture, and expressed mesenchymal stem cell surface markers, high telomerase activity, and normal karyotypes. Importantly, the preserved cells retained bipotent differentiation capacity. Differentiated USCs expressed myogenic specific proteins and contractile function when exposed to myogenic differentiation medium, and they expressed urothelial cell-specific markers and barrier function when exposed to urothelial differentiation medium. These data demonstrated that up to 75% of fresh USCs can be safely persevered in urine for 24 hours and that these cells stored in urine retain their original stem cell properties, indicating that preserved USCs could be available for potential use in cell-based therapy or clinical diagnosis. PMID:23349776

  8. Reliability of spectral analysis of fetal heart rate variability.

    PubMed

    Warmerdam, G J J; Vullings, R; Bergmans, J W M; Oei, S G

    2014-01-01

    Spectral analysis of fetal heart rate variability could provide information on fetal wellbeing. Unfortunately, fetal heart rate recordings are often contaminated by artifacts. Correction of these artifacts affects the outcome of spectral analysis, but it is currently unclear what level of artifact correction facilitates reliable spectral analysis. In this study, a method is presented that estimates the error in spectral powers due to artifact correction, based on the properties of the Continuous Wavelet Transformation. The results show that it is possible to estimate the error in spectral powers. The information about this error makes it possible for clinicians to assess the reliability of spectral analysis of fetal heart rate recordings that are contaminated by artifacts. PMID:25570577

  9. Heart rate dynamics in different levels of Zen meditation.

    PubMed

    Peressutti, Caroline; Martín-González, Juan M; M García-Manso, Juan; Mesa, Denkô

    2010-11-01

    The dynamic interactions among physiological rhythms imbedded in the heart rate signal can give valuable insights into autonomic modulation in conditions of reduced outward attention. Therefore, in this study we analyzed the heart rate variability (HRV) in different levels of practice in Zen meditation (Zazen). Nineteen subjects with variable experience took part in this study. In four special cases we collected both HRV and respiration data. The time series were analyzed in frequency domain and also using the Continuous Wavelet Transform, which detects changes in the time domain and in the frequency domain simultaneously. The shifts in the respiratory modulation of heart rate, or respiratory sinus arrhythmia (RSA), reflect the different levels of practice among practitioners with variable experience in Zazen; in turn the modulation of the RSA may reflect changes in the breathing pattern as in the parasympathetic outflow related to the quality and focus of attention in each stage.

  10. Exaggerated heart rate oscillations during two meditation techniques.

    PubMed

    Peng, C K; Mietus, J E; Liu, Y; Khalsa, G; Douglas, P S; Benson, H; Goldberger, A L

    1999-07-31

    We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude of these oscillations during meditation was significantly greater than in the pre-meditation control state and also in three non-meditation control groups: i) elite athletes during sleep, ii) healthy young adults during metronomic breathing, and iii) healthy young adults during spontaneous nocturnal breathing. This finding, along with the marked variability of the beat-to-beat heart rate dynamics during such profound meditative states, challenges the notion of meditation as only an autonomically quiescent state.

  11. Universal structures of normal and pathological heart rate variability

    PubMed Central

    Gañán-Calvo, Alfonso M.; Fajardo-López, Juan

    2016-01-01

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient. PMID:26912108

  12. Universal structures of normal and pathological heart rate variability.

    PubMed

    Gañán-Calvo, Alfonso M; Fajardo-López, Juan

    2016-02-25

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient.

  13. [An Algorithm for Correcting Fetal Heart Rate Baseline].

    PubMed

    Li, Xiaodong; Lu, Yaosheng

    2015-10-01

    Fetal heart rate (FHR) baseline estimation is of significance for the computerized analysis of fetal heart rate and the assessment of fetal state. In our work, a fetal heart rate baseline correction algorithm was presented to make the existing baseline more accurate and fit to the tracings. Firstly, the deviation of the existing FHR baseline was found and corrected. And then a new baseline was obtained finally after treatment with some smoothing methods. To assess the performance of FHR baseline correction algorithm, a new FHR baseline estimation algorithm that combined baseline estimation algorithm and the baseline correction algorithm was compared with two existing FHR baseline estimation algorithms. The results showed that the new FHR baseline estimation algorithm did well in both accuracy and efficiency. And the results also proved the effectiveness of the FHR baseline correction algorithm.

  14. Universal structures of normal and pathological heart rate variability.

    PubMed

    Gañán-Calvo, Alfonso M; Fajardo-López, Juan

    2016-01-01

    The circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system, and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability, and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient. PMID:26912108

  15. Randomised controlled trial of intrapartum fetal heart rate monitoring.

    PubMed Central

    Mahomed, K.; Nyoni, R.; Mulambo, T.; Kasule, J.; Jacobus, E.

    1994-01-01

    OBJECTIVE--To compare effectiveness of different methods of monitoring intrapartum fetal heart rate. DESIGN--Prospective randomised controlled trial. SETTING--Referral maternity hospital, Harare, Zimbabwe. SUBJECTS--1255 women who were 37 weeks or more pregnant with singleton cephalic presentation and normal fetal heart rate before entry into study. INTERVENTIONS--Intermittent monitoring of fetal heart rate by electronic monitoring, Doppler ultrasound, use of Pinard stethoscope by a research midwife, or routine use of Pinard stethoscope by attending midwife. MAIN OUTCOME MEASURES--Abnormal fetal heart rate patterns, need for operative delivery for fetal distress, neonatal mortality, Apgar scores, admission to neonatal unit, neonatal seizures, and hypoxic ischaemic encephalopathy. RESULTS--Abnormalities in fetal heart rate were detected in 54% (172/318) of the electronic monitoring group, 32% (100/312) of the ultrasonography group, 15% (47/310) of the Pinard stethoscope group, and 9% (28/315) of the routine monitoring group. Caesarean sections were performed for 28% (89%), 24% (76), 10% (32), and 15% (46) of the four groups respectively. Neonatal outcome was best in the ultrasonography group: hypoxic ischaemic encephalopathy occurred in two, one, seven, and 10 cases in the four groups respectively; neonatal seizures occurred only in the last two groups (six and nine cases respectively); and deaths occurred in eight, two, five, and nine cases respectively. CONCLUSIONS--Abnormalities in fetal heart rate were more reliably detected by Doppler ultrasonography than with Pinard stethoscope, and its use resulted in good perinatal outcome. The use of relatively cheap ultrasound monitors should be further evaluated and promoted in obstetric units caring for high risk pregnancies in developing countries with scarce resources. PMID:8136665

  16. Reproducibility of Heart Rate Variability Indices in Children with Cystic Fibrosis

    PubMed Central

    2016-01-01

    Fundamental to the potential utilisation of heart rate variability (HRV) indices as a prognostic tool is the reproducibility of these measures. The purpose of the present study was therefore to investigate the reproducibility of 24-hour derived HRV indices in a clinical paediatric population. Eighteen children (10 boys; 12.4 ± 2.8 years) with mild to moderate Cystic Fibrosis (CF; FVC: 83 ± 12% predicted; FEV1: 80 ± 9% predicted) and eighteen age- and sex-matched controls (10 boys; 12.5 ± 2.7 years) wore a combined ECG and accelerometer for two consecutive days. Standard time and frequency domain indices of HRV were subsequently derived. Reproducibility was assessed by Bland-Altman plots, 95% limits of agreement and intra-class correlation coefficients (ICC). In both groups, there was no systematic difference between days, with the variables demonstrating a symmetrical, homoscedastic distribution around the zero line. The time domain parameters demonstrated a good to excellent reproducibility irrespective of the population considered (ICC: 0.56 to 0.86). In contrast, whilst the frequency domain parameters similarly showed excellent reproducibility in the healthy children (ICC: 0.70 to 0.96), the majority of the frequency domain parameters illustrated a poor to moderate reproducibility in those with CF (ICC: 0.22 to 0.43). The exceptions to this trend were the normalised LF and HF components which were associated with a good to excellent reproducibility. These findings thereby support the utilisation of time and relative frequency domain HRV indices as a prognostic tool in children with CF. Furthermore, the present results highlight the excellent reproducibility of HRV in healthy children, indicating that this may be a useful tool to assess intervention effectiveness in this population. PMID:26968039

  17. Heart rate dynamics before spontaneous onset of ventricular fibrillation in patients with healed myocardial infarcts

    NASA Technical Reports Server (NTRS)

    Makikallio, T. H.; Koistinen, J.; Jordaens, L.; Tulppo, M. P.; Wood, N.; Golosarsky, B.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

    1999-01-01

    The traditional methods of analyzing heart rate (HR) variability have failed to predict imminent ventricular fibrillation (VF). We sought to determine whether new methods of analyzing RR interval variability based on nonlinear dynamics and fractal analysis may help to detect subtle abnormalities in RR interval behavior before the onset of life-threatening arrhythmias. RR interval dynamics were analyzed from 24-hour Holter recordings of 15 patients who experienced VF during electrocardiographic recording. Thirty patients without spontaneous or inducible arrhythmia events served as a control group in this retrospective case control study. Conventional time- and frequency-domain measurements, the short-term fractal scaling exponent (alpha) obtained by detrended fluctuation analysis, and the slope (beta) of the power-law regression line (log power - log frequency, 10(-4)-10(-2) Hz) of RR interval dynamics were determined. The short-term correlation exponent alpha of RR intervals (0.64 +/- 0.19 vs 1.05 +/- 0.12; p <0.001) and the power-law slope beta (-1.63 +/- 0.28 vs -1.31 +/- 0.20, p <0.001) were lower in the patients before the onset of VF than in the control patients, but the SD and the low-frequency spectral components of RR intervals did not differ between the groups. The short-term scaling exponent performed better than any other measurement of HR variability in differentiating between the patients with VF and controls. Altered fractal correlation properties of HR behavior precede the spontaneous onset of VF. Dynamic analysis methods of analyzing RR intervals may help to identify abnormalities in HR behavior before VF.

  18. Estimation of Daily Sodium and Potassium Excretion Using Spot Urine and 24-Hour Urine Samples in a Black Population (Benin).

    PubMed

    Mizéhoun-Adissoda, Carmelle; Houehanou, Corine; Chianéa, Thierry; Dalmay, François; Bigot, André; Preux, Pierre-Marie; Bovet, Pascal; Houinato, Dismand; Desport, Jean-Claude

    2016-07-01

    The 24-hour urine collection method is considered the gold standard for the estimation of ingested potassium and sodium. Because of the impracticalities of collecting all urine over a 24-hour period, spot urine is often used for epidemiological investigations. This study aims to assess the agreement between spot urine and 24-hour urine measurements to determine sodium and potassium intake. A total of 402 participants aged 25 to 64 years were randomly selected in South Benin. Spot urine was taken during the second urination of the day. Twenty-four-hour urine was also collected. Samples (2-mL) were taken and then stored at -20°C. The analysis was carried out using potentiometric dosage. The agreement between spot urine and 24-hour urine measurements was established using Bland-Altman plots. A total of 354 results were analyzed. Daily sodium chloride and potassium chloride urinary excretion means were 10.2±4.9 g/24 h and 2.9±1.4 g/24 h, respectively. Estimated daily sodium chloride and potassium chloride means from the spot urine were 10.7±7.0 g/24 h and 3.9±2.1 g/24 h, respectively. Concordance coefficients were 0.61 at d=-0.5 g, (d±2SD=-11 g and 10.1 g) for sodium chloride and 0.61 at d=-1 g, (d±2SD=-3.8 g and 1.8 g) for potassium chloride. Spot urine method is acceptable for estimating 24-hour urinary sodium and potassium excretion to assess sodium and potassium intake in a black population. However, the confidence interval for the mean difference, which is too large, makes the sodium chloride results inadmissible at a clinical level.

  19. Value of 24-hour Delayed Film of Barium Enema for Evaluation of Colon Transit Function in Young Children with Constipation

    PubMed Central

    Yoo, Ha Yeong; Son, Jae Sung; Park, Hye Won; Kwak, Byung Ok; Kim, Hyeong Su; Bae, Sun Hwan

    2016-01-01

    Background/Aims A colon transit time test using radio-opaque markers (CTTRM) is considered the gold standard for evaluating colon transit function. A 24-hour delayed film of barium enema (BE) has been used as a supplementary method in structural evaluations. The aim of this study was to evaluate the utility of a 24-hour delayed BE film for assessing colon transit function in young children with constipation. Methods In total, 93 children with constipation who performed both single-contrast BE and CTTRM were enrolled in this study. Of these, the data from 70 children were analyzed (males 33, females 37; mean age [range], 5.63 ± 2.94 [2–14] years). The basic principle of the study is “velocity = distance/time”. Time values were identified in both studies, and the colon length and distance of barium movement were measured on the 24-hour delayed BE film. Thus, colon transit velocity values could be calculated using both methods. The correlation between colon transit velocity using a 24-hour delayed BE film versus CTTRM was analyzed statistically. Results Median value (interquartile range) of colon transit velocity using CTTRM was 1.57 (1.07–2.89) cm/hr, and that using BE of that was 1.58 (0.94–2.07) cm/hr. The Spearman correlation coefficient was 0.438 (P < 0.001) for the overall group. The correlation was strongest in children younger than 4 years (r = 0.537, P = 0.032). Conclusions Although the correlation between BE and CTTRM was not very strong, the 24-hour delayed BE film could provide broad information about colon transit function in young children, especially those under 4 years who usually cannot undergo CTTRM. PMID:26979249

  20. Microleakage of Two Self-Adhesive Cements in the Enamel and Dentin After 24 Hours and Two Months

    PubMed Central

    Jaberi Ansari, Zahra; Kalantar Motamedi, Mojdeh

    2014-01-01

    Objective: Microleakage is a main cause of restorative treatment failure. In this study, we compared occlusal and cervical microleakage of two self-adhesive cements after 24 hours and two months. Materials and Methods: In this in-vitro experimental study, class II inlay cavities were prepared on 60 sound human third molars. Composite inlays were fabricated with Z100 composite resin. The teeth were randomly assigned to six groups. RelyX-Arc (control), RelyX-Unicem and Maxcem were used for the first three groups and specimens were stored in distilled water at 37°C for 24 hours. The same cements were used for the remaining three groups, but the specimens were stored for 2 months. The teeth were subjected to 500 thermal cycles (5°C and 55°C) and immersed in 0.5% basic fuchsin for 24 hours and then sectioned mesiodistally and dye penetration was evaluated in a class II cavity with occlusal and cervical margins using X20 magnification stereomicroscope. Data were analyzed using Kruskal Wallis and Mann-Whitney U tests. Results: After 24 hours, cements had significant differences only in cervical margin microleakage (P=0.0001) and microleakage of RelyX-Unicem and Maxcem was significantly more than that of RelyX-Arc (both P=0.0001). Cervical microleakage in RelyX-Unicem and Maxcem was greater than occlusal (P=0.0001 and P=0.001, respectively). Microleakage was not significantly different between the occlusal and cervical margins after 2 months. Conclusion: Cervical microleakage was greater than occlusal in RelyX-Unicem and Maxcem after 24h. The greatest microleakage was reported for the cervical margin of RelyX-Unicem after 24 hours. PMID:25584053

  1. Changes in platelet morphology and function during 24 hours of storage.

    PubMed

    Braune, S; Walter, M; Schulze, F; Lendlein, A; Jung, F

    2014-01-01

    aggregates could be visualized microscopically. After four hours, first debris and very small aggregates occurred. After 24 hours, platelet aggregates and also debris progressively increased. In accordance to this, the CASY system revealed an increase of platelet aggregates (up to 90 μm diameter) with increasing storage time. The percentage of CD62P positive platelets and PF4 increased significantly with storage time in resting PRP. When soluble ADP was added to stored PRP samples, the number of activatable platelets decreased significantly over storage time. The present study reveals the importance of a consequent standardization in the preparation of WB and PRP. Platelet morphology and function, particularly platelet reactivity to adherent or soluble agonists in their surrounding milieu, changed rapidly outside the vascular system. This knowledge is of crucial interest, particularly in the field of biomaterial development for cardiovascular applications, and may help to define common standards in the in vitro hemocompatibility testing of biomaterials.

  2. Assessing the interaction of respiration and heart rate in heart failure and controls using ambulatory Holter recordings.

    PubMed

    Haigney, Mark; Zareba, Wojceich; La Rovere, Maria Teresa; Grasso, Ian; Mortara, David

    2014-01-01

    Breathing is a critical component of cardiopulmonary function, but few tools exist to evaluate respiration in ambulatory patients. Holter monitoring allows accurate diagnosis of a host of cardiac issues, and several investigators have demonstrated the ability to detect respiratory effort on the electrocardiogram. In this study we introduce a myogram signal derived from 12-lead, high frequency Holter as a means of detecting respiratory effort. Using the combined myogram and ECG signal, four novel variables were created: total number of Cheyne-Stokes episodes; the BWRatio, the ratio of power (above baseline) measured one second after peak-to-peak respiratory power, an assessment of the "shape" of the respiratory effort; DRR, the change in RR interval centering around peak inspiration; and minutes of synchronized breathing, a fixed ratio of heart beats to respiratory cycles. These variables were assessed in 24-hour recordings from three cohorts: healthy volunteers (n=33), heart failure subjects from the GISSI HF trial (n=383), and subjects receiving implantable defibrillators with severely depressed left ventricular function enrolled in the M2Risk trial (n=470). We observed a statistically significant 6-fold increase in the number of Cheyne-Stokes episodes (p=0.01 by ANOVA), decreases in BWRatio (p<0.001), as well as decrease in DRR in heart failure subjects; only minutes of synchronized breathing was not significantly decreased in heart failure. This study provides "proof of concept" that novel variables incorporating Holter-derived respiration can distinguish healthy subjects from heart failure. The utility of these variables for predicting heart failure, arrhythmia, and death risk in prospective studies needs to be assessed.

  3. Diving behaviour and heart rate in tufted ducks (Aythya fuligula).

    PubMed

    Stephenson, R; Butler, P J; Woakes, A J

    1986-11-01

    Diving behaviour and heart rate were monitored in tufted ducks diving under circumstances which simulated various environmental conditions such as feeding under ice in winter. When distance to food was increased on a covered outdoor pond, dive duration increased proportionately, but it was calculated that time available for feeding was reduced during the longer-distance 'extended' dives. There was a gradual reduction in heart rate to 77.3 +/- 13.8 beats min-1, which is significantly lower than the resting value of 121.1 +/- 14.1 beats min-1, during the course of extended dives, suggesting that the ducks could gradually switch over to a 'classical' oxygen-conserving response during these prolonged voluntary dives. The duration of the pre-dive preparatory period was positively correlated with dive distance. When the ducks were briefly unable to resurface during an otherwise normal feeding dive in an indoor tank, a situation which may occur if they become disoriented under ice, there was an immediate switch to a full bradycardia. Reduction in heart rate during these 'enclosed' dives occurred only when the ducks were apparently aware of the situation and the rate of onset of bradycardia was very similar to that previously observed during involuntary submersion of tufted ducks. Minimum heart rate was the same at 46 beats min-1 after 15 s of enclosed dives and after 30 s of involuntary submersions, despite the differences in levels of activity in the two situations. PMID:3805996

  4. Diving behaviour and heart rate in tufted ducks (Aythya fuligula).

    PubMed

    Stephenson, R; Butler, P J; Woakes, A J

    1986-11-01

    Diving behaviour and heart rate were monitored in tufted ducks diving under circumstances which simulated various environmental conditions such as feeding under ice in winter. When distance to food was increased on a covered outdoor pond, dive duration increased proportionately, but it was calculated that time available for feeding was reduced during the longer-distance 'extended' dives. There was a gradual reduction in heart rate to 77.3 +/- 13.8 beats min-1, which is significantly lower than the resting value of 121.1 +/- 14.1 beats min-1, during the course of extended dives, suggesting that the ducks could gradually switch over to a 'classical' oxygen-conserving response during these prolonged voluntary dives. The duration of the pre-dive preparatory period was positively correlated with dive distance. When the ducks were briefly unable to resurface during an otherwise normal feeding dive in an indoor tank, a situation which may occur if they become disoriented under ice, there was an immediate switch to a full bradycardia. Reduction in heart rate during these 'enclosed' dives occurred only when the ducks were apparently aware of the situation and the rate of onset of bradycardia was very similar to that previously observed during involuntary submersion of tufted ducks. Minimum heart rate was the same at 46 beats min-1 after 15 s of enclosed dives and after 30 s of involuntary submersions, despite the differences in levels of activity in the two situations.

  5. Voluntary heart rate reduction following yoga using different strategies

    PubMed Central

    Raghavendra, BR; Telles, S; Manjunath, NK; Deepak, KK; Naveen, KV; Subramanya, P

    2013-01-01

    Background/Aims: One month of yoga training has been shown to reduce the pulse rate voluntarily without using external cues. Hence, the present study was designed to understand the strategies used by yoga practitioners and autonomic changes associated with voluntary heart rate reduction. Materials and Methods: Fifty volunteers (group mean age ± S.D., 25.4 ± 4.8 years; 25 males) were assessed in two trials on separate days. Each trial was for 12 minutes, with a ‘pre’ state and ‘during’ state of 6 minutes each. For both trials the ‘pre’ state was relaxation with eyes closed. In the ‘during’ state of Trial I, subjects were asked to voluntarily reduce their heart rate using a strategy of their choice. From their responses to specific questions it was determined that 22 out of 50 persons used breath regulation as a strategy. Hence, in the ‘during’ state of Trial II, subjects were asked to voluntarily reduce their heart rate by breath regulation. Results: In the first trial, the heart rate was reduced by an average of 19.6 beats per minute and in the second trial (with breath regulation exclusively) an average decrease of 22.2 beats per minute was achieved. Conclusions: Hence, the strategy used did not markedly alter the outcome. PMID:23440267

  6. Prognostic factors for death and survival with or without complications in cardiac arrest patients receiving CPR within 24 hours of anesthesia for emergency surgery

    PubMed Central

    Siriphuwanun, Visith; Punjasawadwong, Yodying; Lapisatepun, Worawut; Charuluxananan, Somrat; Uerpairojkit, Ketchada

    2014-01-01

    than or equal to 65 years of age (OR =4.30, 95% CI =1.13–16.42), upper abdominal site of surgery (OR =10.86, 95% CI =1.99–59.13), shock prior to cardiac arrest (OR =3.62, 95% CI =1.30–10.12), arrhythmia prior to cardiac arrest (OR =4.61, 95% CI =1.01–21.13), and cardiac arrest occurring in the postoperative period (OR =3.63, 95% CI =1.31–10.02). Conclusion The mortality and morbidity in patients who received anesthesia for emergency surgery within 24 hours of their first CPR were high, and were associated with identifiable patient comorbidity, age, shock, anatomic site of operation, the timing of cardiac arrest, EKG rhythm, and the duration of CPR. EKG monitoring helps to identify cardiac arrest quickly and diagnose the EKG rhythm as a shockable or nonshockable rhythm, with CPR being performed as per the American Heart Association (AHA) CPR Guidelines 2010. The use of the fast track system in combination with an interdisciplinary team for surgery, CPR, and postoperative care helps to rescue patients in a short time. PMID:25378961

  7. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability.

    PubMed

    Shaffer, Fred; McCraty, Rollin; Zerr, Christopher L

    2014-01-01

    Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain.

  8. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability

    PubMed Central

    Shaffer, Fred; McCraty, Rollin; Zerr, Christopher L.

    2014-01-01

    Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain. PMID:25324790

  9. Remote measurements of heart and respiration rates for telemedicine.

    PubMed

    Zhao, Fang; Li, Meng; Qian, Yi; Tsien, Joe Z

    2013-01-01

    Non-contact and low-cost measurements of heart and respiration rates are highly desirable for telemedicine. Here, we describe a novel technique to extract blood volume pulse and respiratory wave from a single channel images captured by a video camera for both day and night conditions. The principle of our technique is to uncover the temporal dynamics of heart beat and breathing rate through delay-coordinate transformation and independent component analysis-based deconstruction of the single channel images. Our method further achieves robust elimination of false positives via applying ratio-variation probability distributions filtering approaches. Moreover, it enables a much needed low-cost means for preventing sudden infant death syndrome in new born infants and detecting stroke and heart attack in elderly population in home environments. This noncontact-based method can also be applied to a variety of animal model organisms for biomedical research.

  10. Direct observation of homoclinic orbits in human heart rate variability

    NASA Astrophysics Data System (ADS)

    Żebrowski, J. J.; Baranowski, R.

    2003-05-01

    Homoclinic trajectories of the interbeat intervals between contractions of ventricles of the human heart are identified. The interbeat intervals are extracted from 24-h Holter ECG recordings. Three such recordings are discussed in detail. Mappings of the measured consecutive interbeat intervals are constructed. In the second and in some cases in the fourth iterate of the map of interbeat intervals homoclinic trajectories associated with a hyperbolic saddle are found. The homoclinic trajectories are often persistent for many interbeat intervals, sometimes spanning many thousands of heartbeats. Several features typical for homoclinic trajectories found in other systems were identified, including a signature of the gluing bifurcation. The homoclinic trajectories are present both in recordings of heart rate variability obtained from patients with an increased number of arrhythmias and in cases in which the sinus rhythm is dominant. The results presented are a strong indication of the importance of deterministic nonlinear instabilities in human heart rate variability.

  11. Remote Measurements of Heart and Respiration Rates for Telemedicine

    PubMed Central

    Qian, Yi; Tsien, Joe Z.

    2013-01-01

    Non-contact and low-cost measurements of heart and respiration rates are highly desirable for telemedicine. Here, we describe a novel technique to extract blood volume pulse and respiratory wave from a single channel images captured by a video camera for both day and night conditions. The principle of our technique is to uncover the temporal dynamics of heart beat and breathing rate through delay-coordinate transformation and independent component analysis-based deconstruction of the single channel images. Our method further achieves robust elimination of false positives via applying ratio-variation probability distributions filtering approaches. Moreover, it enables a much needed low-cost means for preventing sudden infant death syndrome in new born infants and detecting stroke and heart attack in elderly population in home environments. This noncontact-based method can also be applied to a variety of animal model organisms for biomedical research. PMID:24115996

  12. Ambulatory heart rate range predicts mode-specific mortality and hospitalisation in chronic heart failure

    PubMed Central

    Cubbon, Richard M; Ruff, Naomi; Groves, David; Eleuteri, Antonio; Denby, Christine; Kearney, Lorraine; Ali, Noman; Walker, Andrew M N; Jamil, Haqeel; Gierula, John; Gale, Chris P; Batin, Phillip D; Nolan, James; Shah, Ajay M; Fox, Keith A A; Sapsford, Robert J; Witte, Klaus K; Kearney, Mark T

    2016-01-01

    Objective We aimed to define the prognostic value of the heart rate range during a 24 h period in patients with chronic heart failure (CHF). Methods Prospective observational cohort study of 791 patients with CHF associated with left ventricular systolic dysfunction. Mode-specific mortality and hospitalisation were linked with ambulatory heart rate range (AHRR; calculated as maximum minus minimum heart rate using 24 h Holter monitor data, including paced and non-sinus complexes) in univariate and multivariate analyses. Findings were then corroborated in a validation cohort of 408 patients with CHF with preserved or reduced left ventricular ejection fraction. Results After a mean 4.1 years of follow-up, increasing AHRR was associated with reduced risk of all-cause, sudden, non-cardiovascular and progressive heart failure death in univariate analyses. After accounting for characteristics that differed between groups above and below median AHRR using multivariate analysis, AHRR remained strongly associated with all-cause mortality (HR 0.991/bpm increase in AHRR (95% CI 0.999 to 0.982); p=0.046). AHRR was not associated with the risk of any non-elective hospitalisation, but was associated with heart-failure-related hospitalisation. AHRR was modestly associated with the SD of normal-to-normal beats (R2=0.2; p<0.001) and with peak exercise-test heart rate (R2=0.33; p<0.001). Analysis of the validation cohort revealed AHRR to be associated with all-cause and mode-specific death as described in the derivation cohort. Conclusions AHRR is a novel and readily available prognosticator in patients with CHF, which may reflect autonomic tone and exercise capacity. PMID:26674986

  13. Self-Perception of Swallowing-Related Problems in Laryngopharyngeal Reflux Patients Diagnosed with 24-Hour Oropharyngeal pH Monitoring

    PubMed Central

    Mesallam, Tamer A.; Farahat, Mohamed

    2016-01-01

    Background and Objectives. Swallowing difficulty is considered one of the nonspecific symptoms that many patients with laryngopharyngeal reflux complain of. However, the relationship between laryngopharyngeal reflux and swallowing problems is not clear. The purpose of this work is to explore correlation between swallowing-related problems and laryngopharyngeal reflux (LPR) in a group of patients diagnosed with oropharyngeal pH monitoring and to study the effect of laryngopharyngeal reflux on the patients' self-perception of swallowing problems. Methods. 44 patients complaining of reflux-related problems were included in the study. Patients underwent 24-hour oropharyngeal pH monitoring and were divided into positive and negative LPR groups based on the pH monitoring results. All patient filled out the Dysphagia Handicap Index (DHI) and Reflux Symptom Index (RSI) questionnaires. Comparison was made between the positive and negative LPR groups regarding the results of the DHI and RSI ratings. Also, correlation between DHI scores, RSI scores, and pH monitoring results was studied. Results. Significant difference was reported between positive and negative LPR groups regarding DHI scores, RSI scores, and overall rating of swallowing difficulty. There was significant correlation demonstrated between DHI scores, RSI scores, and 24-hour oropharyngeal pH results. Conclusion. Laryngopharyngeal reflux appears to have a significant impact on patients' self-perception of swallowing problems as measured by DHI. PMID:26966689

  14. Heart Rate Variability During Early Adaptation to Space

    NASA Technical Reports Server (NTRS)

    Toscano, W. B.; Cowings, P. S.

    1994-01-01

    A recent report hypothesized that episodes of space motion sickness (SMS) were reliably associated with low frequency oscillations (less than 0.03 to less than 0.01 Hz) in heart rate variability. This paper archives a large data set for review of investigators in this field which may facilitate the evaluation of this hypothesis. Continuous recording of Electro-cardiography (ECG) and other measures were made for 6 to 12 hours per day (waking hours) of six Shuttle crewmembers for the first 3 mission days of two separate Shuttle flights. Spectral analyses of heart rate variability during approximately 200 hours of inflight is presented. In addition, nearly 200 hours of data collected on these same individuals during ground tests prior to the mission are presented. The Purpose of this Publication is to document the incidence of low frequency oscillations of heart rate in 4 people exposed to microgravity over a period of five days. In addition, this report contains spectral analyses of heart rate data collected on these same individuals during ground-based mission simulations. By archiving these data in this manner, it is our intention to make this information available to other investigators interested in studying this phenomena.

  15. Phase plane based identification of fetal heart rate patterns

    PubMed Central

    Vairavan, Srinivasan; Sriram, Bhargavi; Wilson, James D.; Preissl, Hubert; Eswaran, Hari

    2012-01-01

    Using a phase plane analysis (PPA) of the spatial spread of trajectories of the fetal heart rate and its time-derivative we characterize the fetal heart rate patterns (fHRP) as defined by Nijhuis. For this purpose, we collect 22 fetal magnetocardiogram using a 151 SQUID system from 22 low-risk fetuses in gestational ages ranging from 30 to 37 weeks. Each study lasted for 30 minutes. After the attenuation of the maternal cardiac signals, we identify the R waves using an adaptive Hilbert transform approach and calculate the fetal heart rate. On these datasets, we apply the proposed approach and the traditionally used approaches such as standard deviation of the normal to normal intervals (SDNN) and root mean square of the successive difference (RMSSD). Heart rate patterns are scored by an expert using Nijhuis criteria and revealed A, B, and D patterns. A receiver operator characteristic (ROC) curve is used to assess the performance of the metric to differentiate the different patterns. Results showed that only PPA was able to differentiate all pairs of fHRP with high performance. PMID:22254593

  16. Heart Rate and Stress in a College Setting

    ERIC Educational Resources Information Center

    Elwess, Nancy L.; Vogt, F. Daniel

    2005-01-01

    Conditions producing stress are present in all colleges and universities. In this paper we report on an investigation utilizing heart rate as an indicator of stress in students when participating in activities encountered in a college classroom or laboratory. The activities included presenting an oral report, taking an exam, and participating in a…

  17. Fetal heart rate changes associated with general anesthesia.

    PubMed

    Fedorkow, D M; Stewart, T J; Parboosingh, J

    1989-07-01

    Decreased fetal heart rate variability was noted 90 seconds after the induction of general anesthesia with sodium thiopentone and fentanyl in a patient undergoing basket extraction of a renal calculus at 30 weeks' gestation. The fetal sleep pattern lasted for 105 minutes after the anesthetic was discontinued, 45 minutes after the mother was fully awake.

  18. Infant Heart Rate: A Review of Research and Methodology.

    ERIC Educational Resources Information Center

    Von Bargen, Donna M.

    1983-01-01

    Reviews literature on children up to age one to determine whether heart rate (HR) is a reliable, stable, and valid measure. Considers factors influencing resting HR and the Law of Initial Values, discusses information about response to stimulation and infant perception and affect obtained by using HR measures, and describes HR use in risk…

  19. Transfer entropy analysis of maternal and fetal heart rate coupling.

    PubMed

    Marzbanrad, Faezeh; Kimura, Yoshitaka; Endo, Miyuki; Palaniswami, Marimuthu; Khandoker, Ahsan H

    2015-01-01

    Although evidence of the short term relationship between maternal and fetal heart rates has been found in previous model-based studies, knowledge about the mechanism and patterns of the coupling during gestation is still limited. In this study, a model-free method based on Transfer Entropy (TE) was applied to quantify the maternal-fetal heart rate couplings in both directions. Furthermore, analysis of the lag at which TE was maximum and its changes throughout gestation, provided more information about the mechanism of coupling and its latency. Experimental results based on fetal electrocardiograms (fECGs) and maternal ECG showed the evidence of coupling for 62 out of 65 healthy mothers and fetuses in each direction, by statistically validating against the surrogate pairs. The fetuses were divided into three gestational age groups: early (16-25 weeks), mid (26-31 weeks) and late (32-41 weeks) gestation. The maximum TE from maternal to fetal heart rate significantly increased from early to mid gestation, while the coupling delay on both directions decreased significantly from mid to late gestation. These changes occur concomitant with the maturation of the fetal sensory and autonomic nervous systems with advancing gestational age. In conclusion, the application of TE with delays revealed detailed information about the changes in fetal-maternal heart rate coupling strength and latency throughout gestation, which could provide novel clinical markers of fetal development and well-being.

  20. Volitional Control of Heart Rate During Exercise Stress.

    ERIC Educational Resources Information Center

    LeFevers, Victoria A.

    Thirty five volunteer college women were divided into three groups to determine if heart rate could be conditioned instrumentally and lowered during exercise stress on the treadmill. The three groups were a) experimental group I, 15 subjects who received instrumental conditioning with visual feedback; b) instrumental group II, 9 subjects who…

  1. Heart Rate Variability and Drawing Impairment in Hypoxemic COPD

    ERIC Educational Resources Information Center

    Incalzi, Raffaele Antonelli; Corsonello, Andrea; Trojano, Luigi; Pedone, Claudio; Acanfora, Domenico; Spada, Aldo; D'Addio, Gianni; Maestri, Roberto; Rengo, Franco; Rengo, Giuseppe

    2009-01-01

    We studied 54 patients with hypoxemic chronic obstructive pulmonary disease (COPD). The Mini Mental State Examination and the Mental Deterioration Battery were used for neuropsychological assessment. Heart rate variability (HRV) was assessed based on 24-h Holter ECG recording. Mann-Whitney test was used to compare HRV parameters of patients…

  2. Heart Rate Monitors Promote Physical Education for Children

    ERIC Educational Resources Information Center

    Tipton, Jan; Sander, Allan N.

    2004-01-01

    National health and fitness data suggests that a significant percentage of children are not on a pathway to leading healthy, physically active lifestyles. Many children are leading sedentary lifestyles due to a lack of opportunity, success, or self-motivation in physical activity. Programs that highlight the use of heart rate monitors offer a…

  3. A PC-aided optical foetal heart rate detection system.

    PubMed

    Oweis, Rami J; As'ad, Hala; Aldarawsheh, Amany; Al-Khdeirat, Rawan; Lwissy, Kaldoun

    2014-01-01

    Safe monitoring of foetal heart rate is a valuable tool for the healthy evolution and wellbeing of both foetus and mother. This paper presents a non-invasive optical technique that allows for foetal heart rate detection using a photovoltaic infrared (IR) detector placed on the mother's abdomen. The system presented here consists of a photoplethysmography (PPG) circuit, abdomen circuit and a personal computer equipped with MATLAB. A near IR beam having a wavelength of 880 nm is transmitted through the mother's abdomen and foetal tissue. The received abdominal signal that conveys information pertaining to the mother and foetal heart rate is sensed by a low noise photodetector. The PC receives the signal through the National Instrumentation Data Acquisition Card (NIDAQ). After synchronous detection of the abdominal and finger PPG signals, the designed MATLAB-based software saves, analyses and extracts information related to the foetal heart rate. Extraction is carried out using recursive least squares adaptive filtration. Measurements on eight pregnant women with gestational periods ranging from 35-39 weeks were performed using the proposed system and CTG. Results show a correlation coefficient of 0.978 and a correlation confidence interval between 88-99.6%. The t test results in a p value of 0.034, which is less than 0.05. Low power, low cost, high signal-to-noise ratio, reduction of ambient light effect and ease of use are the main characteristics of the proposed system. PMID:24195701

  4. Exploring the Relationship between Fetal Heart Rate and Cognition

    ERIC Educational Resources Information Center

    Kisilevsky, Barbara S.; Hains, Sylvia M. J.

    2010-01-01

    A relationship between fetal heart rate (HR) and cognition is explored within the context of infant, child and adult studies where the association is well established. Lack of direct access to the fetus and maturational changes limit research paradigms and response measures for fetal studies. Nevertheless, neural regulation of HR shows a number of…

  5. Heart Rate Variability: Effect of Exercise Intensity on Postexercise Response

    ERIC Educational Resources Information Center

    James, David V. B.; Munson, Steven C.; Maldonado-Martin, Sara; De Ste Croix, Mark B. A.

    2012-01-01

    The purpose of the present study was to investigate the influence of two exercise intensities (moderate and severe) on heart rate variability (HRV) response in 16 runners 1 hr prior to (-1 hr) and at +1 hr, +24 hr, +48 hr, and +72 hr following each exercise session. Time domain indexes and a high frequency component showed a significant decrease…

  6. Role of feedback in voluntary control of heart rate.

    PubMed

    Manuck, S B; Levenson, R W; Hinrichsen, J J; Gryll, S L

    1975-06-01

    The relative effectiveness of biofeedback techniques on the voluntary control of heart rate was examined by randomly assigning 32 Ss to one of four feedback conditions in a bi-directional heart-rate control task: (1) no feedback, (2) binary feedback--S was signaled when an interbeat interval had changed in the correct direction, (3) "real-time," proportional feedback--S was provided information about the relative duration of successive interbeat intervals, and (4) numerical, proportional feedback--each interbeat interval was represented as a numeral indicating its relationship to pre-trial mean by direction and magnitude. Significant over-all heart-rate changes were evidenced for both increase and decrease directions, but no differences were found between the feedback conditions. While these data suggest that feedback may be a relatively insignificant factor in voluntary heart-rate control, it was recommended that further investigation examine the role of feedback within the context of other training, mediating and motivational variables.

  7. Relationship between Exercise Heart Rate and Music Tempo Preference

    ERIC Educational Resources Information Center

    Karageorghis, Costas I.; Jones, Leighton; Low, Daniel C.

    2006-01-01

    The present study examined the predicted positive and linear relationship (Iwanaga, 1995a, 1995b) between exercise heart rate and music tempo preference. Initially, 128 undergraduate students (M age = 20.0 years, SD = 0.9) were surveyed to establish their three favorite music artists. A separate experimental group of 29 undergraduates (M age =…

  8. Modelling and control for heart rate regulation during treadmill exercise.

    PubMed

    Su, Steven W; Wang, Lu; Celler, Branko G; Savkin, Andrey V; Guo, Ying

    2006-01-01

    This paper proposes a novel integrated approach for the identification and control of Hammerstein systems to achieve desired heart rate tracking performance for an automated treadmill system. The pseudo-random binary sequence input is employed to decouple the identification of dynamic linear part from static nonlinearity. The powerful e-insensitivity support vector regression is adopted to obtain sparse representations of the inversion of static nonlinearity in order to obtain an approximated linear model of the Hammerstein system. An H(infinity) controller is designed for the approximated linear model to achieve robust tracking performance. This new approach is applied to the design of a computer-controlled treadmill system for the regulation of heart rate during treadmill exercise. Minimizing deviations of heart rate from a preset profile is achieved by controlling the speed of the treadmill. Both conventional proportional-integral-derivative (PID) control and the proposed approaches have been employed for the controller design. The proposed algorithm achieves much better heart rate tracking performance.

  9. Identification and control for heart rate regulation during treadmill exercise.

    PubMed

    Su, Steven W; Wang, Lu; Celler, Branko G; Savkin, Andrey V; Guo, Ying

    2007-07-01

    This paper proposes a novel integrated approach for the identification and control of Hammerstein systems to achieve desired heart rate profile tracking performance for an automated treadmill system. For the identification of Hammerstein systems, the pseudorandom binary sequence input is employed to decouple the identification of dynamic linear part from input nonlinearity. The powerful epsilon-insensitivity support vector regression method is adopted to obtain sparse representations of the inverse of static nonlinearity in order to obtain an approximate linear model of the Hammerstein system. An Hinfinity controller is designed for the approximated linear model to achieve robust tracking performance. This new approach is successfully applied to the design of a computer-controlled treadmill system for the regulation of heart rate during treadmill exercise. Minimizing deviations of heart rate from a preset profile is achieved by controlling the speed of the treadmill. Both conventional proportional-integral-derivative (PID) control and the proposed approaches have been employed for the controller design. The proposed algorithm achieves much better heart rate tracking performance.

  10. An improved method of measuring heart rate using a webcam

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Ouyang, Jianfei; Yan, Yonggang

    2014-09-01

    Measuring heart rate traditionally requires special equipment and physical contact with the subject. Reliable non-contact and low-cost measurements are highly desirable for convenient and comfortable physiological self-assessment. Previous work has shown that consumer-grade cameras can provide useful signals for remote heart rate measurements. In this paper a simple and robust method of measuring the heart rate using low-cost webcam is proposed. Blood volume pulse is extracted by proper Region of Interest (ROI) and color channel selection from image sequences of human faces without complex computation. Heart rate is subsequently quantified by spectrum analysis. The method is successfully applied under natural lighting conditions. Results of experiments show that it takes less time, is much simpler, and has similar accuracy to the previously published and widely used method of Independent Component Analysis (ICA). Benefitting from non-contact, convenience, and low-costs, it provides great promise for popularization of home healthcare and can further be applied to biomedical research.

  11. Factors affecting heart rate variability in preterm infants.

    PubMed

    Cabal, L A; Siassi, B; Zanini, B; Hodgman, J E; Hon, E E

    1980-01-01

    Neonatal heart rate variability (NHRV) was studied in 92 preterm infants (birth weight, 750 to 2,500 gm; gestational age, 28 to 36 weeks). Each infant was monitored continuously during the first 6 hours and for one hour at 24, 48, and 168 hours of life. During each hour NHRV was quantified and related to the following parameters: sex, gestational age, postnatal age, heart rate, and the presence and severity of respiratory distress syndrome (RDS). NHRV in healthy preterm infants was inversely related to heart rate level and directly related to the infant's postnatal age. In healthy babies with gestations of 30 to 36 weeks there was no significant correlation between NHRV and gestation. Decrease in NHRV was significantly related to the severity of RDS, and the reappearance of NHRV in infants with RDS was associated with a good prognosis. Decreased NHRV significantly differentiated the infants with RDS who survived after the fifth hour of life. The data reveal that NHRV (1) should be corrected for heart rate level and postnatal age; (2) is decreased in RDS; and (3) can be used as an indicator of morbidity and mortality in preterm infants with RDS.

  12. Effects of biofeedback training on voluntary heart rate control during dynamic exercise.

    PubMed

    Alvarez Moleiro, M; Villamaín Cid, F

    2001-12-01

    The aims of this study were to (1) compare the effect of biofeedback with that of verbal instructions on the control of heart rate during exercise on a treadmill, (2) test the possible effect of workload on this control, and (3) examine the effect of workload on baseline heart rate at rest and during exercise. The study involved 35 participants who were randomly assigned to each of 4 experimental conditions generated by combining the 2 independent variables: training strategy for heart rate control (heart rate biofeedback or verbal control instructions) and work level (30 or 50% of maximal heart rate). By the end of 5 experimental sessions, participants trained with heart rate biofeedback showed a greater attenuation of the increase in heart rate produced by exercise than participants trained with verbal control instructions. The workload did not influence the voluntary control of heart rate, nor did it affect resting baseline heart rate, but it did affect exercise baseline heart rate. PMID:11802677

  13. [Parameters of heart rate variability during bicycle ergometry test].

    PubMed

    Parnes, E Ia; Koshkina, E V; Krasnoselskiĭ, M Ia

    2003-01-01

    Short-term (5 min) heart rate variability (HRV) was studied before and during submaximal bicycle exercise tests in 27 patients with ischemic heart disease, 23 patients with hypertension and 9 healthy subjects. Low-frequency (0.04 to 0.15 Hz) and high-frequency (0.15 to 0.40 Hz) power components of HRV were significantly decreased during submaximal exercise. The level of load at which abrupt decrease of low-frequency components below 40 ms(2) occurred possibly reflected individual exercise tolerance. Episodes of myocardial ischemia were associated with pronounced decreases of low - frequency HRV components.

  14. Music structure determines heart rate variability of singers

    PubMed Central

    Vickhoff, Björn; Malmgren, Helge; Åström, Rickard; Nyberg, Gunnar; Ekström, Seth-Reino; Engwall, Mathias; Snygg, Johan; Nilsson, Michael; Jörnsten, Rebecka

    2013-01-01

    Choir singing is known to promote wellbeing. One reason for this may be that singing demands a slower than normal respiration, which may in turn affect heart activity. Coupling of heart rate variability (HRV) to respiration is called Respiratory sinus arrhythmia (RSA). This coupling has a subjective as well as a biologically soothing effect, and it is beneficial for cardiovascular function. RSA is seen to be more marked during slow-paced breathing and at lower respiration rates (0.1 Hz and below). In this study, we investigate how singing, which is a form of guided breathing, affects HRV and RSA. The study comprises a group of healthy 18 year olds of mixed gender. The subjects are asked to; (1) hum a single tone and breathe whenever they need to; (2) sing a hymn with free, unguided breathing; and (3) sing a slow mantra and breathe solely between phrases. Heart rate (HR) is measured continuously during the study. The study design makes it possible to compare above three levels of song structure. In a separate case study, we examine five individuals performing singing tasks (1–3). We collect data with more advanced equipment, simultaneously recording HR, respiration, skin conductance and finger temperature. We show how song structure, respiration and HR are connected. Unison singing of regular song structures makes the hearts of the singers accelerate and decelerate simultaneously. Implications concerning the effect on wellbeing and health are discussed as well as the question how this inner entrainment may affect perception and behavior. PMID:23847555

  15. HOW RELIABLE IS 24 HOUR SERUM LITHIUM LEVEL AFTER A TEST DOSE OF LITHIUM IN PREDICTING OPTIMAL LITHIUM DOSE?

    PubMed Central

    Kuruvilla, K.; Shaji, K.S.

    1989-01-01

    SUMMARY 57% of a group of 35 patients treated with Lithium Carbonate at dosages predicted by the nomogram suggested by Cooper et al (1973) failed to reach therapeutic levels of serum lithium. This finding casts serious doubts on the usefulness of the claim by Cooper et al (1973 & 1976) that 24 hour serum lithium level after a test dose of 600 mg. lithium can predict the daily lithium dose. PMID:21927360

  16. Dipstick Spot urine pH does not accurately represent 24 hour urine PH measured by an electrode

    PubMed Central

    Omar, Mohamed; Sarkissian, Carl; Jianbo, Li; Calle, Juan; Monga, Manoj

    2016-01-01

    ABSTRACT Objectives To determine whether spot urine pH measured by dipstick is an accurate representation of 24 hours urine pH measured by an electrode. Materials and Methods We retrospectively reviewed urine pH results of patients who presented to the urology stone clinic. For each patient we recorded the most recent pH result measured by dipstick from a spot urine sample that preceded the result of a 24-hour urine pH measured by the use of a pH electrode. Patients were excluded if there was a change in medications or dietary recommendations or if the two samples were more than 4 months apart. A difference of more than 0.5 pH was considered an inaccurate result. Results A total 600 patients were retrospectively reviewed for the pH results. The mean difference in pH between spot urine value and the 24 hours collection values was 0.52±0.45 pH. Higher pH was associated with lower accuracy (p<0.001). The accuracy of spot urine samples to predict 24-hour pH values of <5.5 was 68.9%, 68.2% for 5.5 to 6.5 and 35% for >6.5. Samples taken more than 75 days apart had only 49% the accuracy of more recent samples (p<0.002). The overall accuracy is lower than 80% (p<0.001). Influence of diurnal variation was not significant (p=0.588). Conclusions Spot urine pH by dipstick is not an accurate method for evaluation of the patients with urolithiasis. Patients with alkaline urine are more prone to error with reliance on spot urine pH. PMID:27286119

  17. Nonlinear control of heart rate variability in human infants.

    PubMed Central

    Sugihara, G; Allan, W; Sobel, D; Allan, K D

    1996-01-01

    Nonlinear analyses of infant heart rhythms reveal a marked rise in the complexity of the electrocardiogram with maturation. We find that normal mature infants (gestation greater than or equal to 35 weeks) have complex and distinctly nonlinear heart rhythms (consistent with recent reports for healthy adults) but that such nonlinearity is lacking in preterm infants (gestation > or = to 27 weeks) where parasympathetic-sympathetic interaction and function are presumed to be less well developed. Our study further shows that infants with clinical brain death and those treated with atropine exhibit a similar lack of nonlinear feedback control. These three lines of evidence support the hypothesis championed by Goldberger et al. [Goldberger, A.L., Rigney, D.R. & West, B.J. (1990) Sci. Am. 262, 43-49] that autonomic nervous system control underlies the nonlinearity and possible chaos of normal heart rhythms. This report demonstrates the acquisition of nonlinear heart rate dynamics and possible chaos in developing human infants and its loss in brain death and with the administration of atropine. It parallels earlier work documenting changes in the variability of heart rhythms in each of these cases and suggests that nonlinearity may provide additional power in characterizing physiological states. PMID:8637921

  18. Nonlinear Control of Heart Rate Variability in Human Infants

    NASA Astrophysics Data System (ADS)

    Sugihara, George; Allan, Walter; Sobel, Daniel; Allan, Kenneth D.

    1996-03-01

    Nonlinear analyses of infant heart rhythms reveal a marked rise in the complexity of the electrocardiogram with maturation. We find that normal mature infants (gestation >= 35 weeks) have complex and distinctly nonlinear heart rhythms (consistent with recent reports for healthy adults) but that such nonlinearity is lacking in preterm infants (gestation <= 27 weeks) where parasympathetic-sympathetic interaction and function are presumed to be less well developed. Our study further shows that infants with clinical brain death and those treated with atropine exhibit a similar lack of nonlinear feedback control. These three lines of evidence support the hypothesis championed by Goldberger et al. [Goldberger, A. L., Rigney, D. R. & West, B. J. (1990) Sci. Am. 262, 43-49] that autonomic nervous system control underlies the nonlinearity and possible chaos of normal heart rhythms. This report demonstrates the acquisition of nonlinear heart rate dynamics and possible chaos in developing human infants and its loss in brain death and with the administration of atropine. It parallels earlier work documenting changes in the variability of heart rhythms in each of these cases and suggests that nonlinearity may provide additional power in characterizing physiological states.

  19. Increased energy density of the home-delivered lunch meal improves 24-hour nutrient intakes in older adults.

    PubMed

    Silver, Heidi J; Dietrich, Mary S; Castellanos, Victoria H

    2008-12-01

    As food intake declines with aging, older adults develop energy and nutrient inadequacies. It is important to design practical approaches to combat insufficient dietary intakes to decrease risk for acute and chronic diseases, illness, and injury. Manipulating the energy density of meals has improved energy intakes in institutional settings, but the effects on community-residing older adults who are at nutrition risk have not been investigated. The aim of this study was to determine whether enhancing the energy density of food items regularly served in a home-delivered meals program would increase lunch and 24-hour energy and nutrient intakes. In a randomized crossover counterbalanced design, 45 older adult Older American Act Nutrition Program participants received a regular and enhanced version of a lunch meal on alternate weeks. The types of foods, portion sizes (gram weight), and appearance of the lunch meal was held constant. Consumption of the enhanced meal increased average lunch energy intakes by 86% (P<0.001) and 24-hour energy intakes by 453 kcal (from 1,423.1+/-62.2 to 1,876.2+/-78.3 kcal, P<0.001). The 24-hour intakes of several key macronutrients and micronutrients also improved. These data suggest that altering the energy density of regularly served menu items is an effective strategy to improve dietary intakes of free-living older adults.

  20. Assessment of 24-hours Aldosterone Administration on Protein Abundances in Fluorescence-Sorted Mouse Distal Renal Tubules by Mass Spectrometry

    PubMed Central

    Jensen, Thomas B; Pisitkun, Trairak; Hoffert, Jason D; Jensen, Uffe B; Fenton, Robert A; Praetorius, Helle A; Knepper, Mark A; Praetorius, Jeppe

    2013-01-01

    Background/Aims Aldosterone exerts multiple long-term effects in the distal renal tubules. The aim of this study was to establish a method for identifying proteins in these tubules that change in abundance by only 24-hours aldosterone administration. Methods Mice endogenously expressing green fluorescent protein (eGFP) in the connecting tubule and cortical collecting ducts were treated with a subcutaneous injection of 2.0 mg/kg aldosterone or vehicle (n=5), and sacrificed 24 hours later. Suspensions of single cells were obtained enzymatically, and eGFP positive cells were isolated by fluorescence activated cell sorting (FACS). Samples of 100 μg proteins were digested with trypsin and labeled with 8-plex iTRAQ reagents and processed for liquid chromatography tandem mass spectrometry (LC-MS/MS). Results FACS yielded 1.4 million cells per mouse. The LC-MS/MS spectra were matched to peptides by the SEQUEST search algorithm, which identified 3002 peptides corresponding to 506 unique proteins of which 20 significantly changed abundance 24-hours after aldosterone injection. Conclusion We find the method suitable and useful for studying hormonal effects on protein abundance in distal tubular segments. PMID:23428628

  1. Pulse transducer with artifact signal attenuator. [heart rate sensors

    NASA Technical Reports Server (NTRS)

    Cash, W. H., Jr.; Polhemus, J. T. (Inventor)

    1980-01-01

    An artifact signal attenuator for a pulse rate sensor is described. The circuit for attenuating background noise signals is connected with a pulse rate transducer which has a light source and a detector for light reflected from blood vessels of a living body. The heart signal provided consists of a modulated dc signal voltage indicative of pulse rate. The artifact signal resulting from light reflected from the skin of the body comprises both a constant dc signal voltage and a modulated dc signal voltage. The amplitude of the artifact signal is greater and the frequency less than that of the heart signal. The signal attenuator circuit includes an operational amplifier for canceling the artifact signal from the output signal of the transducer and has the capability of meeting packaging requirements for wrist-watch-size packages.

  2. Sleep Apnea in Heart Failure Increases Heart Rate Variability and Sympathetic Dominance

    PubMed Central

    Szollosi, Irene; Krum, Henry; Kaye, David; Naughton, Matthew T.

    2007-01-01

    Aims: Sleep disordered breathing (SDB) is common in heart failure and ventilation is known to influence heart rate. Our aims were to assess the influence of SDB on heart rate variability (HRV) and to determine whether central sleep apnea (CSA) and obstructive sleep apnea (OSA) produced different patterns of HRV. Methods and Results: Overnight polysomnography was performed in 21 patients with heart failure and SDB. Two 10-minute segments each of SDB and stable breathing from each patient were visually identified and ECG signal exported for HRV analysis. SDB increased total power (TP) with very low frequency (VLF) power accounting for the greatest increase (1.89±0.54 vs 2.96±0.46 ms2, P <0.001); LF/HF ratio increased during SDB (1.2±1.0 vs 2.7±2.1, P <0.001). Compared to OSA, CSA was associated with lower absolute LF (2.10±0.47 vs 2.52±0.55 ms2, P = 0.049) and HF power (1.69±0.41 vs 2.34±0.58 ms2, P = 0.004), increased VLF% (78.9%±13.4% vs 60.9%±19.2%, P = 0.008), decreased HF% (6.9%±7.8% vs 16.0%±11.7%, P = 0.046) with a trend to higher LF/HF ratio. Conclusions: SDB increases HRV in the setting of increased sympathetic dominance. HRV in CSA and OSA have unique HRV patterns which are likely to reflect the different pathophysiological mechanisms involved. Citation: Szollosi I; Krum H; Kaye D; Naughton MT. Sleep apnea in heart failure increases heart rate variability and sympathetic dominance. SLEEP 2007;30(11):1509-1514. PMID:18041483

  3. Heart Rate and Heart Rate Variability in Dairy Cows with Different Temperament and Behavioural Reactivity to Humans

    PubMed Central

    Tőzsér, János; Szenci, Ottó; Póti, Péter; Pajor, Ferenc

    2015-01-01

    From the 1990s, extensive research was started on the physiological aspects of individual traits in animals. Previous research has established two extreme (proactive and reactive) coping styles in several animal species, but the means of reactivity with the autonomic nervous system (ANS) activity has not yet been investigated in cattle. The aim of this study was the characterization of cardiac autonomic activity under different conditions in cows with different individual characteristics. For this purpose, we investigated heart rate and ANS-related heart rate variability (HRV) parameters of dairy cows (N = 282) on smaller- and larger-scale farms grouped by (1) temperament and (2) behavioural reactivity to humans (BRH). Animals with high BRH scores were defined as impulsive, while animals with low BRH scores were defined as reserved. Cardiac parameters were calculated for undisturbed lying (baseline) and for milking bouts, the latter with the presence of an unfamiliar person (stressful situation). Sympathetic tone was higher, while vagal activity was lower in temperamental cows than in calm animals during rest both on smaller- and larger-scale farms. During milking, HRV parameters were indicative of a higher sympathetic and a lower vagal activity of temperamental cows as compared to calm ones in farms of both sizes. Basal heart rate did not differ between BRH groups either on smaller- or larger-scale farms. Differences between basal ANS activity of impulsive and reserved cows reflected a higher resting vagal and lower sympathetic activity of reserved animals compared to impulsive ones both on smaller- and larger-scale farms. There was no difference either in heart rate or in HRV parameters between groups during milking neither in smaller- nor in larger-scale farms. These two groupings allowed to draw possible parallels between personality and cardiac autonomic activity during both rest and milking in dairy cows. Heart rate and HRV seem to be useful for

  4. General anesthesia suppresses normal heart rate variability in humans

    NASA Astrophysics Data System (ADS)

    Matchett, Gerald; Wood, Philip

    2014-06-01

    The human heart normally exhibits robust beat-to-beat heart rate variability (HRV). The loss of this variability is associated with pathology, including disease states such as congestive heart failure (CHF). The effect of general anesthesia on intrinsic HRV is unknown. In this prospective, observational study we enrolled 100 human subjects having elective major surgical procedures under general anesthesia. We recorded continuous heart rate data via continuous electrocardiogram before, during, and after anesthesia, and we assessed HRV of the R-R intervals. We assessed HRV using several common metrics including Detrended Fluctuation Analysis (DFA), Multifractal Analysis, and Multiscale Entropy Analysis. Each of these analyses was done in each of the four clinical phases for each study subject over the course of 24 h: Before anesthesia, during anesthesia, early recovery, and late recovery. On average, we observed a loss of variability on the aforementioned metrics that appeared to correspond to the state of general anesthesia. Following the conclusion of anesthesia, most study subjects appeared to regain their normal HRV, although this did not occur immediately. The resumption of normal HRV was especially delayed on DFA. Qualitatively, the reduction in HRV under anesthesia appears similar to the reduction in HRV observed in CHF. These observations will need to be validated in future studies, and the broader clinical implications of these observations, if any, are unknown.

  5. Heart Rate Changes in Electroacupuncture Treated Polycystic Ovary in Rats

    PubMed Central

    Ramadoss, Mukilan; Subbiah, Angelie Jessica; Natrajan, Chidambaranathan

    2016-01-01

    Introduction Polycystic Ovary Syndrome (PCOS) is a common metabolic disorder, it affects both humans and animals. It may induce coronary heart disease, obesity and hyperandrogenism. Previous studies show that Low frequency Electroacupuncture (EA) have an effect on PCOS, however the exact pathway is unclear. Aim To find the effect of EA on autonomic activity of the heart in Estradiol Valerate (EV) induced PCOS rats. Materials and Methods Heart rate variability (HRV) was assessed in 3 groups: 1) Control; 2) PCOS rats; and 3) PCOS rats after EA treatment (n=8 in each group). From the time domain analysis and frequency domain analysis (linear measures) HRV analysis was done. EA stimulation was given at low frequency of 2Hz for 15 min on alternate days for 4-5 weeks. Collected data were statistically analysed using One-Way Analysis of Variance with the application of multiple comparisons of Tukey test. Results EA treatment group shows significant reduction in Heart Rate (HR) and low frequency, high frequency ratio (LF/HF); and increase in RR interval, Total Power (TP) when compared to PCOS group. Conclusion The study concludes that EA treatment has a significant effect on reducing sympathetic tone and decreasing HR in PCOS. PMID:27134868

  6. Association of target organ damage with 24-hour systolic and diastolic blood pressure levels and hypertension subtypes in untreated Chinese.

    PubMed

    Wei, Fang-Fei; Li, Yan; Zhang, Lu; Xu, Ting-Yan; Ding, Feng-Hua; Staessen, Jan A; Wang, Ji-Guang

    2014-02-01

    The association of target organ damage with 24-hour systolic and diastolic blood pressure levels and ambulatory hypertension subtypes has not yet been examined in untreated Chinese patients. We measured left ventricular mass index by echocardiography (n=619), the urinary albumin:creatinine ratio (n=1047), and aortic pulse wave velocity by tonometry (n=1013) in 1047 untreated subjects (mean age, 50.6 years; 48.9% women). Normotension was a 24-hour systolic/diastolic blood pressure <130/<80 mm Hg. Hypertension subtypes were isolated diastolic hypertension and mixed systolic plus diastolic hypertension. We assessed associations of interest by multivariable-adjusted linear models. Using normotension as reference, mixed hypertension was associated with higher (P≤0.003) left ventricular mass index (+4.31 g/m(2)), urinary albumin:creatinine ratio (+1.63 mg/mmol), and pulse wave velocity (+0.76 m/s); and isolated diastolic hypertension was associated with similar left ventricular mass index and pulse wave velocity (P≥0.39), but higher urinary albumin:creatinine ratio (+1.24 mg/mmol; P=0.002). In younger participants (<55 years), the mutually independent effect sizes associated with 1 SD increases in 24-hour systolic/diastolic blood pressure were +3.31/-0.36 g/m(2) (P=0.009/0.79) for left ventricular mass index, +1.15/+1.14 mg/mmol (P=0.02/0.04) for the urinary albumin:creatinine ratio, and +0.54/-0.05 m/s (P<0.001/0.54) for pulse wave velocity. In older participants, these estimates were +3.58/+0.30 g/m(2) (P=0.045/0.88), +1.23/+1.05 mg/mmol (P=0.002/0.54), and +0.76/-0.49 m/s (P<0.001/<0.001), respectively. In conclusion, 24-hour systolic blood pressure and mixed hypertension are major determinants of target organ damage irrespective of age and target organ, whereas 24-hour diastolic blood pressure and isolated diastolic hypertension only relate to the urinary albumin:creatinine ratio below middle age.

  7. Effect of Qi-training on blood pressure, heart rate and respiration rate.

    PubMed

    Lee, M S; Kim, B G; Huh, H J; Ryu, H; Lee, H S; Chung, H T

    2000-05-01

    To examine the physiological effects of Korean traditional Qi-training, we investigated the changes in blood pressure, heart and respiratory rates before, during and after ChunDoSunBup (CDSB) Qi-training. Twelve normal healthy CDSB Qi-trainees (19-37 years old; trained for 1.3 +/- 0.2 years; 9 men and 3 women) volunteered to participate in this study. Heart rate, respiratory rate, systolic blood pressure and rate-pressure product were significantly decreased during Qi-training. From these results, we suggest that CDSB Qi-training has physiological effects that indicate stabilization of cardiovascular system.

  8. Heart Rate and Energy Expenditure During Aqua Dynamics.

    PubMed

    Vickery, S R; Cureton, K J; Langstaff, J L

    1983-03-01

    In brief: The heart rate, oxygen uptake, and energy expenditure of three young women were measured during 20-minute low-gear, 30-minute middle-gear, and 60-minute high-gear aqua dynamics workouts. All three workouts were moderate in intensity, eliciting average heart rates of 132 to 143 beats min(-1) (70% to 77% HR max), average oxygen uptakes of 1.2 to 1.3 liters min(-1) (51% to 57% VO2 max), and average energy expenditures of 5.9 to 6.5 kcals min(-1) The findings indicate that aqua dynamics could be a beneficial conditioning program for people who have relatively low physical work capacity and enjoy swimming but cannot conveniently engage in lap swimming. PMID:27409547

  9. Association between oral variables and heart rate variability.

    PubMed

    Santana, Milana Drumond Ramos; de Souza, Ana Cecilia Amorim; de Abreu, Luiz Carlos; Valenti, Vitor E

    2013-12-27

    The heart rate variability is a useful method to assess cardiac autonomic modulation in patients undergoing dental procedures, because knowledge of physiological conditions provides greater security to the professional as well as the possibility of a better plan treatment to patient benefit. The aim of our study was to describe the association between cardiac autonomic control and dental variables. We consulted the databases Medline, SciELO, Lilacs and Cochrane, using the terms "autonomic", "dentistry", "heart rate variability", "cardiovascular physiology." The selected studies indicated a strong relationship between dental variables and HRV. There was an association between malocclusion, TMD, dental procedures cirugia and low HRV. Thus, they become more studies that relate to HRV in dental science, especially in clinical practice.

  10. Real-time signal processing for fetal heart rate monitoring.

    PubMed

    Ibrahimy, Muhammad I; Ahmed, Firoz; Mohd Ali, M A; Zahedi, Edmond

    2003-02-01

    An algorithm based on digital filtering, adaptive thresholding, statistical properties in the time domain, and differencing of local maxima and minima has been developed for the simultaneous measurement of the fetal and maternal heart rates from the maternal abdominal electrocardiogram during pregnancy and labor for ambulatory monitoring. A microcontroller-based system has been used to implement the algorithm in real-time. A Doppler ultrasound fetal monitor was used for statistical comparison on five volunteers with low risk pregnancies, between 35 and 40 weeks of gestation. Results showed an average percent root mean square difference of 5.32% and linear correlation coefficient from 0.84 to 0.93. The fetal heart rate curves remained inside a +/- 5-beats-per-minute limit relative to the reference ultrasound method for 84.1% of the time. PMID:12665042

  11. Respiration and heart rate in exercising land crabs.

    PubMed

    Herreid, C F; Lee, L W; Shah, G M

    1979-05-01

    Land Crabs, Cardisoma guanhumi, were fitted with respiratory masks and E.C.G. electrodes and run for 10 or 20 min on a treadmill at speeds of 150 and 300 cm/min. Aerobic metabolism increased linearly with the speed of locomotion. The recovery period was characterized by a large oxygen debt. The primary respiratory adjustment to exercise was an increased ventilation volume; only a minor increase in oxygen extraction occurred. The respiratory exchange ratio increased during exercise and during recovery, presumably correlated with a metabolic acidosis. These results are similar to data collected for exercising vertebrates and the net cost of locomotion of crabs appears similar to quadrupeds. However, the heart rate in exercising crabs changed in an unexpected way: during moderate exercise no change was noted, but during heavy exercise a bradycardia developed. The reduction in rate resulted from an increase in interbeat interval and frequent pauses in the heart beat.

  12. Prognostic significance of heart rate variability in centenarians.

    PubMed

    Shimizu, Kenichiro; Arai, Yasumichi; Hirose, Nobuyoshi; Yonemoto, Takayuki; Wakida, Yasushi

    2002-01-01

    We studied the significance for further survival of heart rate variability and other variables in the very elderly. In 1992, we assessed activities of daily living, cognitive function, and nutritional status in 27 centenarians with no disease, in addition to the power of the heart rate variability in the ultralow, very low, low (LF), and high frequency (HF) bands. In 1996, we assessed survival in these centenarians; 17 had died and 10 were still living. Logistic regression analysis using backward elimination detected three factors, dementia, LF/HF, and age, that independently influenced mortality. Mortality risk increased with greater age in 1992, more severe dementia, or lower LF/HF. Sympathetic nerve activity, represented as LF/HF, may be associated with prognosis for survival in centenarians.

  13. gHRV: Heart rate variability analysis made easy.

    PubMed

    Rodríguez-Liñares, L; Lado, M J; Vila, X A; Méndez, A J; Cuesta, P

    2014-08-01

    In this paper, the gHRV software tool is presented. It is a simple, free and portable tool developed in python for analysing heart rate variability. It includes a graphical user interface and it can import files in multiple formats, analyse time intervals in the signal, test statistical significance and export the results. This paper also contains, as an example of use, a clinical analysis performed with the gHRV tool, namely to determine whether the heart rate variability indexes change across different stages of sleep. Results from tests completed by researchers who have tried gHRV are also explained: in general the application was positively valued and results reflect a high level of satisfaction. gHRV is in continuous development and new versions will include suggestions made by testers.

  14. Cholesterol enhances classical conditioning of the rabbit heart rate response

    PubMed Central

    Schreurs, Bernard G.; Smith-Bell, Carrie A.; Darwish, Deya S.; Wang, Desheng; Burhans, Lauren B.; Gonzales-Joekes, Jimena; Deci, Stephen; Stankovic, Goran; Sparks, D. Larry

    2007-01-01

    The cholesterol-fed rabbit is a model of atherosclerosis and has been proposed as an animal model of Alzheimer's disease. Feeding rabbits cholesterol has been shown to increase the number of beta amyloid immunoreactive neurons in the cortex. Addition of copper to the drinking water of cholesterol-fed rabbits can increase this number still further and may lead to plaque-like structures. Classical conditioning of the nictitating membrane response in cholesterol-fed rabbits is retarded in the presence of these plaque-like structures but may be facilitated in their absence. In a factorial design, rabbits fed 2% cholesterol or a normal diet (0% cholesterol) for 8 weeks with or without copper added to the drinking water were given trace classical conditioning using a tone and periorbital electrodermal stimulation to study the effects of cholesterol and copper on classical conditioning of heart rate and the nictitating membrane response. Cholesterol-fed rabbits showed significant facilitation of heart rate conditioning and conditioning-specific modification of heart rate relative to normal diet controls. Consistent with previous research, cholesterol had minimal effects on classical conditioning of the nictitating membrane response when periorbital electrodermal stimulation was used as the unconditioned stimulus. Immunohistochemical analysis showed a significant increase in the number of beta amyloid positive neurons in the cortex, hippocampus and amygdala of the cholesterol-fed rabbits. Supplementation of drinking water with copper increased the number of beta amyloid positive neurons in the cortex of cholesterol-fed rabbits but did not produce plaque-like structures or have a significant effect on heart rate conditioning. The data provide additional support for our finding that, in the absence of plaques, dietary cholesterol may facilitate learning and memory. PMID:17466388

  15. Changes in heart rate variability during concentration meditation.

    PubMed

    Phongsuphap, Sukanya; Pongsupap, Yongyuth; Chandanamattha, Pakorn; Lursinsap, Chidchanok

    2008-11-28

    This study aims at investigating changes in heart rate variability (HRV) measured during meditation. The statistical and spectral measures of HRV from the RR intervals were analyzed. Results indicate that meditation may have different effects on health depending on frequency of the resonant peak that each meditator can achieve. The possible effects may concern resetting baroreflex sensitivity, increasing the parasympathetic tone, and improving efficiency of gas exchange in the lung.

  16. Spectral photoplethysmographic imaging sensor fusion for enhanced heart rate detection

    NASA Astrophysics Data System (ADS)

    Amelard, Robert; Clausi, David A.; Wong, Alexander

    2016-03-01

    Continuous heart rate monitoring can provide important context for quantitative clinical assessment in scenarios such as long-term health monitoring and disability prevention. Photoplethysmographic imaging (PPGI) systems are particularly useful for such monitoring scenarios as contact-based devices pose problems related to comfort and mobility. Each pixel can be regarded as a virtual PPG sensor, thus enabling simultaneous measurements of multiple skin sites. Existing PPGI systems analyze temporal PPGI sensor uctuations related to hemodynamic pulsations across a region of interest to extract the blood pulse signal. However, due to spatially varying optical properties of the skin, the blood pulse signal may not be consistent across all PPGI sensors, leading to inaccurate heart rate monitoring. To increase the hemodynamic signal-to-noise ratio (SNR), we propose a novel spectral PPGI sensor fusion method for enhanced estimation of the true blood pulse signal. Motivated by the observation that PPGI sensors with high hemodynamic SNR exhibit a spectral energy peak at the heart rate frequency, an entropy-based fusion model was formulated to combine PPGI sensors based on the sensors' spectral energy distribution. The optical PPGI device comprised a near infrared (NIR) sensitive camera and an 850 nm LED. Spatially uniform irradiance was achieved by placing optical elements along the LED beam, providing consistent illumination across the skin area. Dual-mode temporally coded illumination was used to negate the temporal effect of ambient illumination. Experimental results show that the spectrally weighted PPGI method can accurately and consistently extract heart rate information where traditional region-based averaging fails.

  17. The effects of hypnosis on heart rate variability.

    PubMed

    Yüksel, Ramazan; Ozcan, Osman; Dane, Senol

    2013-01-01

    Uslu et al. (2012 ) suggested that hypnotic status can modulate cerebral blood flow. The authors investigated the effects of hypnosis on heart rate variability (HRV). In women, HRV decreased during hypnosis. Posthypnotic values were higher compared to prehypnotic and hypnotic values. Women had highest HRV parameters in the posthypnotic condition. It appears that hypnosis can produce cardiac and cognitive activations. Hypnotherapy may be useful in some cardiac clinical conditions characterized by an autonomic imbalance or some cardiac arrhythmias.

  18. Effects of chronic sleep deprivation on autonomic activity by examining heart rate variability, plasma catecholamine, and intracellular magnesium levels.

    PubMed

    Takase, Bonpei; Akima, Takashi; Satomura, Kimio; Ohsuzu, Fumitaka; Mastui, Takemi; Ishihara, Masayuki; Kurita, Akira

    2004-10-01

    Chronic sleep deprivation is associated with cardiovascular events. In addition, autonomic activity determined from the levels of the heart rate variability (HRV), plasma catecholamine, and intracellular magnesium (Mg) are important in the pathophysiology of cardiovascular events. This study therefore aimed to determine the effects of chronic sleep deprivation on autonomic activity by examining the HRV, plasma catecholamine, and intracellular magnesium levels. Thirty (30) healthy male college students ranging in age from 20 to 24 years of age (average 22 +/- 1 years; mean +/- SD) with no coronary risk factors such as hypertension, diabetes mellitus, hyperlipidemia or a family history of premature coronary artery disease (CAD) were included in the study. Over a 4-week period, the volunteers' plasma levels of epinephrine, norepinephrine, and erythrocyte-Mg were measured. The study was made during the 4 weeks before and immediately after college finals exams. HRV, obtained from 24-hour ambulatory ECG monitoring, included time and frequency domain indices. The HRV indices and erythrocyte-Mg decreased while norepinephrine increased during chronic sleep deprivation. It is concluded that chronic sleep deprivation causes an autonomic imbalance and decreases intracellular Mg, which could be associated with chronic sleep deprivation-induced cardiovascular events. PMID:15754837

  19. Heart rate variability and sympathovagal balance: pharmacological validation

    PubMed Central

    Bootsma, M.; Swenne, C.A.; Janssen, M.J.A.; Cats, V. Manger; Schalij, M.J.

    2003-01-01

    Rationale We validated heart rate (HR) and six time and six frequency domain measures of heart rate variability (HRV) as estimators of autonomic outflow in 44 young healthy male subjects. Gold standards for autonomic outflow were the Rosenblueth-Simeone factors m (sympathetic tone) and n (vagal tone), and the sympathovagal balance m·n, determined by two-stage complete autonomic blockade. Methods Rank correlations were computed between HR and the HRV measures obtained before autonomic blockade, and m, n and m·n. Also, the maximal mean performances (averaged sensitivity and specificity) for HR and HRV as discriminators between low and high values of m, n or m·n were computed. Results The spectral HRV measures showed less good correlations and performances than the time domain HRV measures. Correlations with sympathetic tone were all below 0.31. Respiratory sinus arrhythmia during 15 cycles/min metronome breathing was superior in estimating vagal tone and sympathovagal balance (correlations -0.71/-0.73; both performances 0.82), heart rate scored similarly for assessing the sympathovagal balance (correlation 0.71; performance 0.82). Conclusions It does not appear justified to evaluate HR or HRV in terms of sympathetic tone, vagal tone, or sympathovagal balance. HR and HRV are specifically weak in assessing sympathetic tone. Respiratory sinus arrhythmia during 15 cycles/min metronome breathing is superior in assessing vagal tone. Current HRV analysis techniques offer no advantages compared with HR in assessing the sympathovagal balance. PMID:25696224

  20. Heart rate and blood lactate responses during competitive Olympic boardsailing.

    PubMed

    Guével, A; Maïsetti, O; Prou, E; Dubois, J J; Marini, J F

    1999-02-01

    The rules of competitive boardsailing events were changed before the Atlanta Olympic Games. Pumping the sail (pulling repeatedly on the rig) is now allowed and the duration of races has been shortened. Eight members of the French national team (mean age 23+/-2.7 years) participated in this study. Their cardiac and metabolic responses were assessed by measuring heart rate and blood lactate concentration during various competitive events in two strengths of wind (light vs. moderate). Heart rate was higher in light (87.4+/-4.3% HRmax; mean racing time 37 min) than in moderate wind conditions (82.9+/-5.3% HRmax; mean racing time 33 min). The mean post-race blood lactate concentration (5.2+/-1.0 mmol x l(-1)) was not affected by the wind conditions. Mean heart rate was highest during downwind legs (88.0+/-3.1% HRmax; duration 7-10 min). The races consisted of two laps, the first of which induced significantly higher cardiac demands than the second. We conclude that the changes to the rules of competitive boardsailing have increased the cardiac and metabolic efforts involved. PMID:10069270

  1. 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.

  2. Modeling heart rate variability including the effect of sleep stages.

    PubMed

    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. PMID:26931582

  3. Impaired heart rate recovery in patients with endemic fluorosis.

    PubMed

    Adali, M Koray; Varol, Ercan; Aksoy, Fatih; Icli, Atilla; Ersoy, I Hakki; Ozaydin, Mehmet; Erdogan, Dogan; Dogan, Abdullah

    2013-06-01

    The objective of the present study was to determine the heart rate recovery index (HRRI), a marker of autonomic nervous system function in patients with endemic fluorosis. Forty patients with endemic fluorosis (16 men/24 women) and 40 age-, sex-, and body mass index-matched healthy controls (16 men/24 women) with normal fluoride intake were enrolled in this study. HRRI was calculated by subtracting the heart rate values at the first, second, and third minutes of the recovery phase from the peak heart rate (HRRI 1, HRRI 2, HRRI 3). Urine fluoride levels of fluorosis patients were significantly (P < 0.001) higher than control subjects as expected. HRRI 2 was significantly lower in fluorosis patients than in the controls. The incidence of abnormal HRRI 1 was significantly higher in fluorosis patients than in the controls (P < 0.05). We observed that HRRI, a marker of autonomic nervous system function, is impaired in patients with chronic fluorosis.

  4. Experimental heart rate regulation in cycle-ergometer exercises.

    PubMed

    Paradiso, Michele; Pietrosanti, Stefano; Scalzi, Stefano; Tomei, Patrizio; Verrelli, Cristiano Maria

    2013-01-01

    The heart rate can be effectively used as a measure of the exercise intensity during long duration cycle-ergometer exercises: precisely controlling the heart rate (HR) becomes crucial especially for athletes or patients with cardiovascular/obesity problems. The aim of this letter is to experimentally show how the nonlocal and nonswitching nonlinear control that has been recently proposed in the literature for the HR regulation in treadmill exercises can be effectively applied to cycle-ergometer exercises at constant cycling speed. The structure of the involved nonlinear model for the HR dynamics in cycle-ergometer exercises is mathematically inspired by the structure of a recently identified and experimentally validated nonlinear model for the HR dynamics in treadmill exercises: the role played by the treadmill speed is played here by the work load while the zero speed case for the treadmill exercise is here translated into the cycling operation under zero work load. Experimental results not only validate the aforementioned nonlinear model but also demonstrate the effectiveness--in terms of precise HR regulation--of an approach which simply generalizes to the nonlinear framework the classical proportional-integral control design. The possibility of online modifying the HR reference on the basis of the heart rate variability (HRV) is also suggested and experimentally motivated.

  5. Heart rate & blood lactate response in amateur competitive boxing.

    PubMed

    Ghosh, A K; Goswami, A; Ahuja, A

    1995-10-01

    The heart rate (HR) and blood lactate response were studied on 26 senior national level boxers in competitive bouts to explore the aerobic-anaerobic metabolism as well as the training status of the players. The aerobic capacity (VO2 max) of the players were determined using graded running protocol on a treadmill. Heart rate and blood lactate concentration were measured during warm up and boxing rounds. The mean relative VO2 max of the heavy weight category boxers was lower (P < 0.05) than the other two weight categories. No interweight category as well as inter-round differences were observed in the heart rate and blood lactate concentration of the boxers, excepting in the 48-57 kg category, the mean lactate levels in the second and third rounds were higher (P < 0.05) than in the first round. When all weight categories were pooled the mean HR and blood lactate levels were 178 beats/min and 8.24 mMol/l respectively. The study highlights that in amateur boxing, irrespective of the weight category and aerobic capacity, the anaerobic adaptability of the boxers was the same. The training requirements of the boxers demand that they should be also to tolerate a high blood lactate level (approx. 9.0 mMol/l) and a high HR (approx. 180 beats/min) over a total duration of one bout.

  6. Local dynamics of heart rate: detection and prognostic implications.

    PubMed

    Moss, Travis J; Lake, Douglas E; Moorman, J Randall

    2014-10-01

    The original observation that reduced heart rate variability (HRV) confers poor prognosis after myocardial infarction has been followed by many studies of heart rate dynamics. We tested the hypothesis that an entropy-based local dynamics measure gave prognostic information in ambulatory patients undergoing 24-h electrocardiography. In this context, entropy is the probability that short templates will find matches in the time series. We studied RR interval time series from 24-h Holter monitors of 1564 consecutive patients over age 39. We generated histograms of the count of templates as a function of the number of templates matches in short RR interval time series, and found characteristic appearance of histograms for atrial fibrillation, sinus rhythm with normal HRV, and sinus rhythm with reduced HRV and premature ventricular contractions (PVCs). We developed statistical models to detect the abnormal dynamic phenotype of reduced HRV with PVCs and fashioned a local dynamics score (LDs) that, after controlling for age, added more prognostic information than other standard risk factors and common HRV metrics, including, to our surprise, the PVC count and the HRV of normal-to-normal intervals. Addition of the LDs to a predictive model using standard risk factors significantly increased the ROC area and the net reclassification improvement was 27%. We conclude that abnormal local dynamics of heart rate confer adverse prognosis in patients undergoing 24-h ambulatory electrocardiography.

  7. Mesenchymal Stem Cells Improve Heart Rate Variability and Baroreflex Sensitivity in Rats with Chronic Heart Failure

    PubMed Central

    de Morais, Sharon Del Bem Velloso; da Silva, Luiz Eduardo Virgilio; Lataro, Renata Maria; Silva, Carlos Alberto Aguiar; de Oliveira, Luciano Fonseca Lemos; de Carvalho, Eduardo Elias Vieira; Simões, Marcus Vinicius; da Silva Meirelles, Lindolfo; Fazan, Rubens

    2015-01-01

    Heart failure induced by myocardial infarct (MI) attenuates the heart rate variability (HRV) and baroreflex sensitivity, which are important risk factors for life-threatening cardiovascular events. Therapies with mesenchymal stem cells (MSCs) have shown promising results after MI. However, the effects of MSCs on hemodynamic (heart rate and arterial pressure) variability and baroreflex sensitivity in chronic heart failure (CHF) following MI have not been evaluated thus far. Male Wistar rats received MSCs or saline solution intravenously 1 week after ligation of the left coronary artery. Control (noninfarcted) rats were also evaluated. MI size was assessed using single-photon emission computed tomography (SPECT). The left ventricular ejection fraction (LVEF) was evaluated using radionuclide ventriculography. Four weeks after MSC injection, the animals were anesthetized and instrumented for chronic ECG recording and catheters were implanted in the femoral artery to record arterial pressure. Arterial pressure and HRVs were determined in time and frequency domain (spectral analysis) while HRV was also examined using nonlinear methods: DFA (detrended fluctuation analysis) and sample entropy. The initial MI size was the same among all infarcted rats but was reduced by MSCs. CHF rats exhibited increased myocardial interstitial collagen and sample entropy combined with the attenuation of the following cardiocirculatory parameters: DFA indices, LVEF, baroreflex sensitivity, and HRV. Nevertheless, MSCs hampered all these alterations, except the LVEF reduction. Therefore, 4 weeks after MSC therapy was applied to CHF rats, MI size and myocardial interstitial fibrosis decreased, while baroreflex sensitivity and HRV improved. PMID:26059001

  8. Skeletal muscle electrical stimulation improves baroreflex sensitivity and heart rate variability in heart failure rats.

    PubMed

    Lazzarotto Rucatti, Ananda; Jaenisch, Rodrigo Boemo; Rossato, Douglas Dalcin; Bonetto, Jéssica Hellen Poletto; Ferreira, Janaína; Xavier, Leder Leal; Sonza, Anelise; Dal Lago, Pedro

    2015-12-01

    The goal of the current study was to evaluate the effects of electrical stimulation (ES) on the arterial baroreflex sensitivity (BRS) and cardiovascular autonomic control in rats with chronic heart failure (CHF). Male Wistar rats were designated to one of four groups: placebo sham (P-Sham, n=9), ES sham (ES-Sham, n=9), placebo CHF (P-CHF, n=9) or ES CHF (ES-CHF, n=9). The ES was adjusted at a low frequency (30 Hz), duration of 250 μs, with hold and rest time of 8s (4 weeks, 30 min/day, 5 times/week). It was applied on the gastrocnemius muscle with intensity to produce a visible muscle contraction. The rats assigned to the placebo groups performed the same procedures with the equipment turned off. The two-way ANOVA and the post hoc Student-Newman-Keuls tests (P<0.05) were used to data comparison. The BRS was higher in ES-Sham group compared to the P-Sham group and the ES-CHF group compared to the P-CHF group. ES was able to decrease heart rate sympatho-vagal modulation and peripheral sympathetic modulation in ES-CHF compared to P-CHF group. Interestingly, heart rate sympatho-vagal modulation was similar between ES-CHF and P-Sham groups. Thus, ES enhances heart rate parasympathetic modulation on heart failure (ES-CHF) compared to placebo (P-CHF), with consequent decrease of sympatho-vagal balance in the ES-CHF group compared to the P-CHF. The results show that a 4 week ES protocol in CHF rats enhances arterial BRS and cardiovascular autonomic control.

  9. Autonomic Control of Heart Rate and of QT Interval Variability Influences Arrhythmic Risk in Long QT Syndrome Type 1

    PubMed Central

    Porta, Alberto; Girardengo, Giulia; Bari, Vlasta; George, Alfred L.; Brink, Paul A.; Goosen, Althea; Crotti, Lia; Schwartz, Peter J.

    2014-01-01

    BACKGROUND A puzzling feature of the long QT syndrome (LQTS) is that family members carrying the same mutation often have divergent symptoms and clinical outcomes. OBJECTIVES We tested the hypothesis that vagal and sympathetic control, as assessed from spectral analysis of spontaneous beat-to-beat variability of RR and QT intervals from standard 24-hour electrocardiogram Holter recordings, can modulate the severity of LQTS type 1 (LQT1) in 46 members of a South-African LQT1 founder population carrying the clinically severe KCNQ1-A341V mutation. METHODS Nonmutation carriers (NMCs, n = 14) were compared with mutation carriers (MCs, n = 32), 22 with and 10 without major symptoms. We assessed the effect of circadian rhythm and of beta-blocker therapy over traditional time and frequency domain RR and QT variability indices. RESULTS The asymptomatic MCs differed significantly from the symptomatic MCs and from NMCs in less vagal control of heart rate and more reactive sympathetic modulation of the QT interval, particularly during daytime when arrhythmia risk for LQT1 patients is greatest. CONCLUSIONS The present data identify an additional factor contributing to the differential arrhythmic risk among LQT1 patients carrying the same mutation. A “normal” autonomic control confers a high risk, whereas patients with higher sympathetic control of the QT interval and reduced vagal control of heart rate are at lower risk. This differential “autonomic make-up,” likely under genetic control, will allow refinement of risk stratification within LQTS families, leading to more targeted management. PMID:25634836

  10. Bluetooth(Registered Trademark) Heart Rate Monitors for Spaceflight

    NASA Technical Reports Server (NTRS)

    Buxton, Roxanne E.; West, Michael R.; Kalogera, Kent L.; Hanson, Andrea M.

    2016-01-01

    Heart rate monitoring is required during exercise for crewmembers aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data is required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth® heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health on board ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) was worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_RHM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the two data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. REULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6%error), followed by CS4 (3.3%error), CS3 (6.4%error), and CS2 (9.2%error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to get the best quality data. CS2 will be used in an

  11. Classifying work rate from heart rate measurements using an adaptive neuro-fuzzy inference system.

    PubMed

    Kolus, Ahmet; Imbeau, Daniel; Dubé, Philippe-Antoine; Dubeau, Denise

    2016-05-01

    In a new approach based on adaptive neuro-fuzzy inference systems (ANFIS), field heart rate (HR) measurements were used to classify work rate into four categories: very light, light, moderate, and heavy. Inter-participant variability (physiological and physical differences) was considered. Twenty-eight participants performed Meyer and Flenghi's step-test and a maximal treadmill test, during which heart rate and oxygen consumption (VO2) were measured. Results indicated that heart rate monitoring (HR, HRmax, and HRrest) and body weight are significant variables for classifying work rate. The ANFIS classifier showed superior sensitivity, specificity, and accuracy compared to current practice using established work rate categories based on percent heart rate reserve (%HRR). The ANFIS classifier showed an overall 29.6% difference in classification accuracy and a good balance between sensitivity (90.7%) and specificity (95.2%) on average. With its ease of implementation and variable measurement, the ANFIS classifier shows potential for widespread use by practitioners for work rate assessment. PMID:26851475

  12. 24-Hour Forecasting of CME/Flare Eruptions from Active-Region Magnetograms (Invited)

    NASA Astrophysics Data System (ADS)

    Falconer, D. A.; Barghouty, A.; Khazanov, I. G.; Moore, R. L.

    2010-12-01

    We have developed an automated tool for forecasting severe space weather from full-disk magnetograms. This tool is now being used on a trial basis by NASA’s Space Radiation Analysis Group (SRAG) at JSC. SRAG is responsible for the monitoring and forecasting of exposure the astronauts to particle radiation. The tool is described in Falconer, Barghouty, Khazanov, and Moore (2010), submitted to Space Weather. The new software tool is designed for the empirical forecasting of M- and X-class flares, coronal mass ejections, and solar energetic particle events. For each of these event types, the algorithm is based on the empirical relationship between the event rate and a proxy of the active region’s free magnetic energy. The relationship is determined from ~40,000 active-region magnetograms from ~1,300 active regions that were observed within 30 heliographic degrees from disk center by SOHO/MDI, and that have known histories of flare, coronal mass ejection, and solar energetic particle event production during disk passage. The tool automatically extracts each strong-field magnetic areas from an MDI full-disk magnetogram, identifies each as a NOAA active region, and measures the proxy of the active region’s free magnetic energy from the extracted magnetogram. For each active region, the empirical relationship is then used to convert the free magnetic energy proxy into the active region’s expected event rate (see figure). The expected event rate in turn can be readily converted into the probability that the active region will produce such an event in a given forward time window. We can make this tool applicable to the full-disk line-of-sight magnetograms from SDO/HMI or as a backup, from NSO/GONG. By empirically determining the conversion of the value of free-energy proxy measured from an HMI magnetogram to that which would be measured from an MDI magnetogram, we can use the HMI magnetograms with the empirical relationships determined from our MDI data base to make

  13. Meal-induced 24-hour profile of circulating glycated insulin in type 2 diabetic subjects measured by a novel radioimmunoassay.

    PubMed

    Lindsay, John R; McKillop, Aine M; Mooney, Mark H; Flatt, Peter R; Bell, Patrick M; O'harte, Finbarr P M

    2003-05-01

    Increasing evidence supports a role for glycated insulin in the insulin-resistant state of type 2 diabetes. We measured 24-hour profiles of plasma glycated insulin, using a novel radioimmunoassay (RIA), to evaluate the effects of meal stimulation and intermittent fasting on circulating concentrations of plasma glycated insulin in type 2 diabetes. Patients (n = 6; hemoglobin A(1c) [HbA(1c)], 7.2% +/- 0.6%; fasting plasma glucose, 7.4 +/- 0.7 mmol/L; body mass index [BMI], 35.7 +/- 3.5 kg/m(2); age, 56.3 +/- 4.4 years) were admitted for 24 hours and received a standardized meal regimen. Half-hourly venous samples were taken for plasma glycated insulin, glucose, insulin, and C-peptide concentrations between 8 am and midnight and 2-hourly overnight. The mean plasma glycated insulin concentration over 24 hours was 27.8 +/- 1.2 pmol/L with a mean ratio of insulin:glycated insulin of 11:1. Circulating glucose, insulin, C-peptide, and glycated insulin followed a basal and meal-related pattern with most prominent increments following breakfast, lunch, and evening meal, respectively. The mean concentrations of glycated insulin during the morning, afternoon, evening, and night-time periods were 24.4 +/- 2.5, 28.7 +/- 2.3, 31.1 +/- 2.1, and 26.2 +/- 1.5 pmol/L, respectively, giving significantly higher molar ratios of insulin:glycated insulin of 18.0:1, 14.2:1, and 12.7:1 compared with 7.0:1 at night (P <.01 to P <.001). These data demonstrate that glycated insulin circulates at relatively high concentrations in type 2 diabetes with a diurnal pattern of basal and meal-stimulated release. A higher proportion of glycated insulin circulates at night suggestive of differences in metabolic clearance compared with native insulin.

  14. Effects of Fibrinogen Concentrate on Thrombin Generation, Thromboelastometry Parameters, and Laboratory Coagulation Testing in a 24-Hour Porcine Trauma Model

    PubMed Central

    Zentai, Christian; Solomon, Cristina; van der Meijden, Paola E. J.; Spronk, Henri M. H.; Schnabel, Jonas; Rossaint, Rolf

    2015-01-01

    Introduction: In a 24-hour porcine model of liver injury, we showed that fibrinogen supplementation does not downregulate endogenous fibrinogen synthesis. Here we report data from the same study showing the impact of fibrinogen on coagulation variables. Materials and Methods: Coagulopathy was induced in 20 German land race pigs by hemodilution and blunt liver injury. Animals randomly received fibrinogen concentrate (100 mg/kg) or saline. Coagulation parameters were assessed and thromboelastometry (ROTEM) was performed. Results: Fibrinogen concentrate significantly reduced the prolongations of EXTEM clotting time, EXTEM clot formation time, and prothrombin time induced by hemodilution and liver injury. A decrease in clot strength was also ameliorated. Endogenous thrombin potential was significantly higher in the fibrinogen group than in the control group, 20 minutes (353 ± 24 vs 289 ± 22 nmol/L·min; P < .05) and 100 minutes (315 ± 40 vs 263 ± 38 nmol/L·min; P < .05) after the start of infusion. However, no significant between-group differences were seen in other thrombin generation parameters or in d-dimer or thrombin–antithrombin levels. Fibrinogen–platelet binding was reduced following liver injury, with no significant differences between groups. No significant between-group differences were observed in any parameter at ∼12 and ∼24 hours. Conclusion: This study suggests that, in trauma, fibrinogen supplementation may shorten some measurements of the speed of coagulation initiation and produce a short-lived increase in endogenous thrombin potential, potentially through increased clotting substrate availability. Approximately 12 and 24 hours after starting fibrinogen concentrate/saline infusion, all parameters measured in this study were comparable in the 2 study groups. PMID:25948634

  15. The Relationship Between 24-Hour Symptoms and COPD Exacerbations and Healthcare Resource Use: Results from an Observational Study (ASSESS).

    PubMed

    Miravitlles, Marc; Worth, Heinrich; Soler-Cataluña, Juan José; Price, David; De Benedetto, Fernando; Roche, Nicolas; Godtfredsen, Nina S; van der Molen, Thys; Löfdahl, Claes-Göran; Padullés, Laura; Ribera, Anna

    2016-10-01

    This observational study assessed the relationship between nighttime, early-morning and daytime chronic obstructive pulmonary disease (COPD) symptoms and exacerbations and healthcare resource use. COPD symptoms were assessed at baseline in patients with stable COPD using a standardised questionnaire during routine clinical visits. Information was recorded on exacerbations and healthcare resource use during the year before baseline and during a 6-month follow-up period. The main objective of the analysis was to determine the predictive nature of current symptoms for future exacerbations and healthcare resource use. 727 patients were eligible (65.8% male, mean age: 67.2 years, % predicted forced expiratory volume in 1 second: 52.8%); 698 patients (96.0%) provided information after 6 months. Symptoms in any part of the day were associated with a prior history of exacerbations (all p < 0.05) and nighttime and early-morning symptoms were associated with the frequency of primary care visits in the year before baseline (both p < 0.01). During follow-up, patients with baseline symptoms during any part of the 24-hour day had more exacerbations than patients with no symptoms in each period (all p < 0.05); there was also an association between 24-hour symptoms and the frequency of primary care visits (all p ≤ 0.01). Although there was a significant association between early-morning and daytime symptoms and exacerbations during follow-up (both p < 0.01), significance was not maintained when adjusted for potential confounders. Prior exacerbations were most strongly associated with future risk of exacerbation. The results suggest 24-hour COPD symptoms do not independently predict future exacerbation risk.

  16. Developing a Method to Test the Validity of 24 Hour Time Use Diaries Using Wearable Cameras: A Feasibility Pilot

    PubMed Central

    Kelly, Paul; Thomas, Emma; Doherty, Aiden; Harms, Teresa; Burke, Órlaith; Gershuny, Jonathan; Foster, Charlie

    2015-01-01

    Self-report time use diaries collect a continuous sequenced record of daily activities but the validity of the data they produce is uncertain. This study tests the feasibility of using wearable cameras to generate, through image prompted interview, reconstructed 'near-objective' data to assess their validity. 16 volunteers completed the Harmonised European Time Use Survey (HETUS) diary and used an Autographer wearable camera (recording images at approximately 15 second intervals) for the waking hours of the same 24-hour period. Participants then completed an interview in which visual images were used as prompts to reconstruct a record of activities for comparison with the diary record. 14 participants complied with the full collection protocol. We compared time use and number of discrete activities from the diary and camera records (using 10 classifications of activity). In terms of aggregate totals of daily time use we found no significant difference between the diary and camera data. In terms of number of discrete activities, participants reported a mean of 19.2 activities per day in the diaries, while image prompted interviews revealed 41.1 activities per day. The visualisations of the individual activity sequences reveal some potentially important differences between the two record types, which will be explored at the next project stage. This study demonstrates the feasibility of using wearable cameras to reconstruct time use through image prompted interview in order to test the concurrent validity of 24-hour activity time-use budgets. In future we need a suitably powered study to assess the validity and reliability of 24-hour time use diaries. PMID:26633807

  17. Skinfold thickness is related to cardiovascular autonomic control as assessed by heart rate variability and heart rate recovery.

    PubMed

    Esco, Michael R; Williford, Henry N; Olson, Michele S

    2011-08-01

    The purpose of this study was to determine if heart rate recovery (HRR) and heart rate variability (HRV) are related to maximal aerobic fitness and selected body composition measurements. Fifty men (age = 21.9 ± 3.0 years, height = 180.8 ± 7.2 cm, weight = 80.4 ± 9.1 kg, volunteered to participate in this study. For each subject, body mass index (BMI), waist circumference (WC), and the sum of skinfolds across the chest, abdomen, and thigh regions (SUMSF) were recorded. Heart rate variability (HRV) was assessed during a 5-minute period while the subjects rested in a supine position. The following frequency domain parameters of HRV were recorded: normalized high-frequency power (HFnu), and low-frequency to high-frequency power ratio (LF:HF). To determine maximal aerobic fitness (i.e., VO2max), each subject performed a maximal graded exercise test on a treadmill. Heart rate recovery was recorded 1 (HRR1) and 2 (HRR2) minutes during a cool-down period. Mean VO2max and BMI for all the subjects were 49.5 ± 7.5 ml·kg(-1)·min(-1) and 24.7 ± 2.2 kg·m(-2), respectively. Although VO2max, WC, and SUMSF was each significantly correlated to HRR and HRV, only SUMSF had a significant independent correlation to HRR1, HRR2, HFnu, LF:HF (p < 0.01). The results of the regression procedure showed that SUMSF accounted for the greatest variance in HRR1, HRR2, HFnu, and LF:HF (p < 0.01). The results of this study suggest that cardiovascular autonomic modulation is significantly related to maximal aerobic fitness and body composition. However, SUMSF appears to have the strongest independent relationship with HRR and HRV, compared to other body composition parameters and VO2max.

  18. The Success of Surgery in the First 24 Hours in Patients with Esophageal Perforation

    PubMed Central

    Bayram, Ahmet Sami; Erol, Mehmet Muharrem; Melek, Huseyin; Colak, Mehmet Ali; Kermenli, Tayfun; Gebitekin, Cengiz

    2015-01-01

    Objective: Esophageal perforation (EP) is a critical and potentially life-threatening condition with considerable rates of morbidity and mortality. Despite many advances in thoracic surgery, the management of patients with EP is still controversial. Materials and Methods: We retrospectively reviewed 34 patients treated for EP, 62% male, mean age 53.9 years. Sixty-two percent of the EPs were iatrogenic. Spontaneous and traumatic EP rates were 26% and 6%, respectively. Three patients had EP in the cervical esophagus and 31 in the thoracic esophagus. Results: Mean time to initial treatment was 34.2 hours. Twenty patients comprised the early group <24 h) and 14 patients the late group (>24 h). Management of the EP included primary closure in 30 patients, non-surgical treatment in two, stent in one and resection in one. Mortality occurred in nine of the 34 patients (26%). Mortality was EP-related in four patients. Three of the nine patients that died were in the early group (p<0.05). Mean hospital stay was 13.4 days. Conclusion: EP remains a potentially fatal condition and requires early diagnosis and accurate treatment to prevent the morbidity and mortality. PMID:25745344

  19. Neural control of heart rate: the role of neuronal networking.

    PubMed

    Kember, G; Armour, J A; Zamir, M

    2011-05-21

    Neural control of heart rate, particularly its sympathetic component, is generally thought to reside primarily in the central nervous system, though accumulating evidence suggests that intrathoracic extracardiac and intrinsic cardiac ganglia are also involved. We propose an integrated model in which the control of heart rate is achieved via three neuronal "levels" representing three control centers instead of the conventional one. Most importantly, in this model control is effected through networking between neuronal populations within and among these layers. The results obtained indicate that networking serves to process demands for systemic blood flow before transducing them to cardiac motor neurons. This provides the heart with a measure of protection against the possibility of "overdrive" implied by the currently held centrally driven system. The results also show that localized networking instabilities can lead to sporadic low frequency oscillations that have the characteristics of the well-known Mayer waves. The sporadic nature of Mayer waves has been unexplained so far and is of particular interest in clinical diagnosis.

  20. The Automated Self-Administered 24-Hour Dietary Recall for Children, 2012 version, for youth aged 9 to 11 Years: A validation study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our objective was to validate the 2012 version of the Automated Self-Administered 24-Hour Dietary Recall for Children (ASA24-Kids-2012), a self-administered web-based 24-hour dietary recall (24hDR) instrument, among children aged 9 to 11 years, in two sites using a quasiexperimental design. In one s...

  1. A Plaque Disruption Index Identifies Patients with Non-STE-Type 1 Myocardial Infarction within 24 Hours of Troponin Positivity

    PubMed Central

    Al-Mohaissen, Maha A.; Carere, Ronald G.; Mancini, G. B. John; Humphries, Karin H.; Whalen, Beth A.; Lee, Terry; Scheuermeyer, Frank X.; Ignaszewski, Andrew P.

    2016-01-01

    Background Markers of plaque destabilization and disruption may have a role in identifying non-STE- type 1 Myocardial Infarction in patients presenting with troponin elevation. We hypothesized that a plaque disruption index (PDI) derived from multiple biomarkers and measured within 24 hours from the first detectable troponin in patients with acute non-STE- type 1 MI (NSTEMI-A) will confirm the diagnosis and identify these patients with higher specificity when compared to individual markers and coronary angiography. Methods We examined 4 biomarkers of plaque destabilization and disruption: myeloperoxidase (MPO), high-sensitivity interleukin-6, myeloid-related protein 8/14 (MRP8/14) and pregnancy-associated plasma protein-A (PAPP-A) in 83 consecutive patients in 4 groups: stable non-obstructive coronary artery disease (CAD), stable obstructive CAD, NSTEMI-A (enrolled within 24 hours of troponin positivity), and NSTEMI-L (Late presentation NSTEMI, enrolled beyond the 24 hour limit). The PDI was calculated and the patients’ coronary angiograms were reviewed for evidence of plaque disruption. The diagnostic performance of the PDI and angiography were compared. Results Compared to other biomarkers, MPO had the highest specificity (83%) for NSTEMI-A diagnosis (P<0.05). The PDI computed from PAPP-A, MRP8/14 and MPO was higher in NSTEMI-A patients compared to the other three groups (p<0.001) and had the highest diagnostic specificity (87%) with 79% sensitivity and 86% accuracy, which were higher compared to those obtained with MPO, but did not reach statistical significance (P>0.05 for all comparisons). The PDI had higher specificity and accuracy for NSTEMI-A diagnosis compared to coronary angiography (P<0.05). Conclusions A PDI measured within 24 hour of troponin positivity has potential to identify subjects with acute Non-ST-elevation type 1 MI. Additional evidence using other marker combinations and investigation in a sufficiently large non-selected cohort is warranted

  2. Influence of mild cold on the components of 24 hour thermogenesis in rats.

    PubMed Central

    Brown, D; Livesey, G; Dauncey, M J

    1991-01-01

    1. The influence of two weeks' acclimation to either 28 degrees C (thermal neutrality) or 21 degrees C (mild cold) on 24 h heat production and motor activity has been investigated in male Wistar rats. Food intake was controlled and provided as a single meal of approximately 170 kJ per day. Mathematical modelling was used to relate metabolic rate to measured movement and time of day. 2. For animals at thermal neutrality it was clear that metabolic rate increased during periods of substantial measured movement and returned to baseline during periods of minimal activity. Total heat production could therefore be divided into two components: underlying and movement-induced thermogenesis. 3. At 21 degrees C, a more complex model was needed. During periods of substantial activity, the relation between metabolic rate and movement was similar to that at 28 degrees C and total heat production could be divided into the same two components of underlying and movement-induced thermogenesis. However, during periods of prolonged inactivity, a different model was required, which included a component of extra metabolic activity, termed supplementary thermogenesis. By fitting this model to data at 28 and 21 degrees C, it was possible to partition 24 h heat production into the three possible sources of underlying, movement-induced and supplementary thermogenesis. 4. Total 24 h heat production was approximately 25% higher for rats at 21 compared with 28 degrees C (P less than 0.01) and underlying thermogenesis was approximately 20% higher for those in the mild cold (P less than 0.01). Measured movement was significantly reduced in the mild cold (P less than 0.05) although it was energetically less efficient since there was no difference in movement-induced thermogenesis, which accounted for 18 and 15% of total heat production at 28 and 21 degrees C respectively. Supplementary thermogenesis was observed only in the mild cold and it accounted for approximately 6% of 24 h heat production

  3. Respiratory modulation and baroreflex control of heart rate in space

    NASA Astrophysics Data System (ADS)

    Verheyden, Bart; Couckuyt, Kurt; Liu, Jiexin; Aubert, Andre

    During everyday life, gravity constantly stresses the human circulation by diminishing venous return in the upright position. This induces baroreflex-mediated cardiovascular adjustments that are aimed to prevent the blood pressure from falling. In weightlessness, gravitational pressure gradients do not arise in the circulation so that baroreflex function remains chronically unchallenged. This may contribute to the development of post spaceflight orthostatic intolerance. The purpose of this study was to evaluate respiratory modulation and baroreflex control of heart rate after a week of weightlessness in space. We tested the hypothesis that cardiovascular control in space will be similar to the baseline supine condition on Earth. We studied nine male cosmonauts during seven different space missions aboard the ISS (age 40 - 52 yrs, height 1.69 - 1.85 m, weight 67 - 90 kg). Data collection was performed between 30 and 45 days before launch in the standing and supine positions, and after 8 days in space. Cosmonauts were carefully trained to perform in-flight data collection by themselves. They were instructed to pace their breathing to a fixed rate of 12 breaths per minute (0.2 Hz) for a total duration of 3 minutes. The electrocardiogram and beat-by-beat finger arterial blood pressure were recorded at 1-kHz sample rate. Respiratory rate was evaluated using an abdominal pressure sensor. We used power spectral analysis to calculate respiratory sinus arrhythmia (RSA) as well as the low-frequency (0.04 - 0.15 Hz) powers of spontaneous oscillations in heart rate and systolic blood pressure. Baroreflex sensitivity (BRS) was estimated in the time domain using cross-correlation analysis. As expected, there was a rise in heart rate upon assuming the standing position before space- flight (59 ± 6 to 79 ± 11 beats per min; p ¡ 0.001). This was accompanied by an increase in mean arterial blood pressure (84 ± 6 to 93 ± 6 mmHg; p ¡ 0.001). Standing up further induced a marked

  4. Cross-validation of a composite pain scale for preschool children within 24 hours of surgery.

    PubMed

    Suraseranivongse, S; Santawat, U; Kraiprasit, K; Petcharatana, S; Prakkamodom, S; Muntraporn, N

    2001-09-01

    This study was designed to cross-validate a composite measure of the pain scales CHEOPS (Children's Hospital of Eastern Ontario Pain Scale), OPS (Objective Pain Scale, simplified for parent use by replacing blood pressure measurement with observation of body language or posture), TPPPS (Toddler Preschool Postoperative Pain Scale) and FLACC (Face, Legs, Activity, Cry, Consolability) in 167 Thai children aged 1-5.5 yr. The pain scales were translated and tested for content, construct and concurrent validity, including inter-rater and intra-rater reliabilities. Discriminative validity in immediate and persistent pain for the age groups < or =3 and >3 yr were also studied. The children's behaviour was videotaped before and after surgery, before analgesia had been given in the post-anaesthesia care unit (PACU), and on the ward. Four observers then rated pain behaviour from rearranged videotapes. The decision to treat pain was based on routine practice and was made by a researcher unaware of the rating procedure. All tools had acceptable content validity and excellent inter-rater and intra-rater reliabilities (intraclass correlation >0.9 and >0.8 respectively). Construct validity was determined by the ability to differentiate the group with no pain before surgery and a high pain level after surgery, before analgesia (P<0.001). The positive correlations among all scales in the PACU and on the ward (r=0.621-0.827, P<0.0001) supported concurrent validity. Use of the kappa statistic indicated that CHEOPS yielded the best agreement with the routine decision to treat pain. The younger and older age groups both yielded very good agreement in the PACU but only moderate agreement on the ward. On the basis of data from this study, we recommend CHEOPS as a valid, reliable and practical tool. PMID:11517123

  5. Characterizing heart rate variability by scale-dependent Lyapunov exponent

    NASA Astrophysics Data System (ADS)

    Hu, Jing; Gao, Jianbo; Tung, Wen-wen

    2009-06-01

    Previous studies on heart rate variability (HRV) using chaos theory, fractal scaling analysis, and many other methods, while fruitful in many aspects, have produced much confusion in the literature. Especially the issue of whether normal HRV is chaotic or stochastic remains highly controversial. Here, we employ a new multiscale complexity measure, the scale-dependent Lyapunov exponent (SDLE), to characterize HRV. SDLE has been shown to readily characterize major models of complex time series including deterministic chaos, noisy chaos, stochastic oscillations, random 1/f processes, random Levy processes, and complex time series with multiple scaling behaviors. Here we use SDLE to characterize the relative importance of nonlinear, chaotic, and stochastic dynamics in HRV of healthy, congestive heart failure, and atrial fibrillation subjects. We show that while HRV data of all these three types are mostly stochastic, the stochasticity is different among the three groups.

  6. Heart dimensions may influence the occurrence of the heart rate deflection point in highly trained cyclists

    PubMed Central

    Lucia, A.; Carvajal, A.; Boraita, A.; Serratosa, L.; Hoyos, J.; Chicharro, J. L.

    1999-01-01

    OBJECTIVES: To determine whether the heart rate (HR) response to exercise in 21 highly trained cyclists (mean (SD) age 25 (3) years) was related to their heart dimensions. METHODS: Before performing an incremental exercise test involving a ramp protocol with workload increases of 25 W/min, each subject underwent echocardiographic evaluation of the following variables: left ventricular end diastolic internal diameter (LVIDd), left ventricular posterior wall thickness at end diastole (LVPWTd), interventricular septal wall thickness at end diastole (IVSTd), left ventricular mass index (LVMI), left atrial dimension (LAD), longitudinal left atrial (LLAD) and right atrial (LRAD) dimensions, and the ratio of early to late (E/A) diastolic flow velocity. RESULTS: The HR response showed a deflection point (HRd) at about 85% VO2MAX in 66.7% of subjects (D group; n = 14) and was linear in 33.3% (NoD group; n = 7). Several echocardiographic variables (LVMI, LAD, LLAD, LRAD) indicative of heart dimensions were similar in each group. However, mean LPWTd (p<0.01) and IVSTd (p<0.05) values were significantly higher in the D group. Finally, no significant difference between groups was found with respect to the E/A. CONCLUSIONS: The HR response is curvilinear during incremental exercise in a considerable number of highly trained endurance athletes-that is, top level cyclists. The departure of HR increase from linearity may predominantly occur in athletes with thicker heart walls. 


 PMID:10597846

  7. Exercise thermoregulation in men after 1 and 24-hours of 6 degrees head-down tilt

    NASA Technical Reports Server (NTRS)

    Ertl, A. C.; Dearborn, A. S.; Weidhofer, A. R.; Bernauer, E. M.; Greenleaf, J. E.

    2000-01-01

    BACKGROUND: Exercise thermoregulation is dependent on heat loss by increased skin blood flow (convective and conductive heat loss) and through enhanced sweating (evaporative heat loss). Reduction of plasma volume (PV), increased plasma osmolality, physical deconditioning, and duration of exposure to simulated and actual microgravity reduces the ability to thermoregulate during exercise. HYPOTHESIS: We hypothesized that 24 h of head down tilt (HDT24) would alter thermoregulatory responses to a submaximal exercise test and result in a higher exercise rectal temperature (Tre) when compared with exercise Tre after 1 h of head down tilt (HDT1). METHODS: Seven men (31+/-SD 6 yr, peak oxygen uptake (VpO2peak) of 44+/-6 ml x kg(-1) x min(-1)) were studied during 70 min of supine cycling at 58+/-SE 1.5% VO2peak at 22.0 degrees C Tdb and 47% rh. RESULTS: Relative to pre-tilt sitting chair rest data, HDT1 resulted in a 6.1+/-0.9% increase and HDT24 in a 4.3+/-2.3% decrease in PV (delta = 10.4% between experiments, p<0.05) while plasma osmolality remained unchanged (NS). Pre-exercise Tre was elevated after HDT24 (36.71 degrees C +/-0.06 HDT1 vs. 36.93 degrees C+/-0.11 HDT24, p<0.05). The 70 min of exercise did not alter this relationship (p<0.05) with respective end exercise increases in Tre to 38.01 degrees C and 38.26 degrees C (degrees = 1.30 degrees C (HDT1) and 1.33 degrees C (HDT24)). While there were no pre-exercise differences in mean skin temperature (Tsk), a significant (p<0.05) time x treatment interaction occurred during exercise: after min 30 in HDT24 the Tsk leveled off at 31.1 degrees C, while it continued to increase reaching 31.5 degrees C at min 70 in HDT1. A similar response (NS) occurred in skin blood velocity. Neither local sweating rates nor changes in body weight during exercise of -1.63+/-0.24 kg (HDT1) or - 1.33+/-0.09 kg (HDT24) were different (NS) between experiments. CONCLUSION: While HDT24 resulted in elevated pre-exercise Tre, reduced PV

  8. Recovery of function after vagus nerve stimulation initiated 24 hours after fluid percussion brain injury.

    PubMed

    Smith, Douglas C; Tan, Arlene A; Duke, Andrea; Neese, Steven L; Clough, Richard W; Browning, Ronald A; Jensen, Robert A

    2006-10-01

    Recent evidence from our laboratory demonstrated in laboratory rats that stimulation of the vagus nerve (VNS) initiated 2 h after lateral fluid percussion brain injury (FPI) accelerates the rate of recovery on a variety of behavioral and cognitive tests. VNS animals exhibited a level of performance comparable to that of sham-operated uninjured animals by the end of a 2-week testing period. The effectiveness of VNS was further evaluated in the present study in which initiation of stimulation was delayed until 24 h post-injury. Rats were subjected to a moderate FPI and tested on the beam walk, skilled forelimb reaching, locomotor placing, forelimb flexion and Morris water maze tasks for 2 weeks following injury. VNS (30 sec trains of 0.5 mA, 20.0-Hz biphasic pulses) was initiated 24 h post-injury and continued at 30-min intervals for the duration of the study, except for brief periods when the animals were detached for behavioral assessments. Consistent with our previous findings when stimulation was initiated 2 h post-injury, VNS animals showed significantly faster rates of recovery compared to controls. By the last day of testing (day 14 post-injury), the FPI-VNS animals were performing significantly better than the FPI-no-VNS animals and were not significantly different from shams in all motor and sensorimotor tasks. Performance in the Morris water maze indicated that the VNS animals acquired the task more rapidly on days 11-13 post-injury. On day 14, the FPI-VNS animals did not differ in the latency to find the platform from sham controls, whereas the injured controls did; however, the FPI-VNS animals and injured controls were not significantly different. Despite the lack of significant histological differences between the FPI groups, VNS, when initiated 24 h following injury, clearly attenuated the ensuing behavioral deficits and enhanced acquisition of the cognitive task. The results are discussed with respect to the norepinephrine hypothesis. PMID:17020489

  9. Heart rate responses to autonomic challenges in obstructive sleep apnea.

    PubMed

    Macey, Paul M; Kumar, Rajesh; Woo, Mary A; Yan-Go, Frisca L; Harper, Ronald M

    2013-01-01

    Obstructive sleep apnea (OSA) is accompanied by structural alterations and dysfunction in central autonomic regulatory regions, which may impair dynamic and static cardiovascular regulation, and contribute to other syndrome pathologies. Characterizing cardiovascular responses to autonomic challenges may provide insights into central nervous system impairments, including contributions by sex, since structural alterations are enhanced in OSA females over males. The objective was to assess heart rate responses in OSA versus healthy control subjects to autonomic challenges, and, separately, characterize female and male patterns. We studied 94 subjects, including 37 newly-diagnosed, untreated OSA patients (6 female, age mean ± std: 52.1 ± 8.1 years; 31 male aged 54.3 ± 8.4 years), and 57 healthy control subjects (20 female, 50.5 ± 8.1 years; 37 male, 45.6 ± 9.2 years). We measured instantaneous heart rate with pulse oximetry during cold pressor, hand grip, and Valsalva maneuver challenges. All challenges elicited significant heart rate differences between OSA and control groups during and after challenges (repeated measures ANOVA, p<0.05). In post-hoc analyses, OSA females showed greater impairments than OSA males, which included: for cold pressor, lower initial increase (OSA vs. control: 9.5 vs. 7.3 bpm in females, 7.6 vs. 3.7 bpm in males), OSA delay to initial peak (2.5 s females/0.9 s males), slower mid-challenge rate-of-increase (OSA vs. control: -0.11 vs. 0.09 bpm/s in females, 0.03 vs. 0.06 bpm/s in males); for hand grip, lower initial peak (OSA vs. control: 2.6 vs. 4.6 bpm in females, 5.3 vs. 6.0 bpm in males); for Valsalva maneuver, lower Valsalva ratio (OSA vs. control: 1.14 vs. 1.30 in females, 1.29 vs. 1.34 in males), and OSA delay during phase II (0.68 s females/1.31 s males). Heart rate responses showed lower amplitude, delayed onset, and slower rate changes in OSA patients over healthy controls, and impairments may be more pronounced in females. The

  10. Microstructure of the rat's intake of food, sucrose and saccharin in 24-hour tests.

    PubMed

    Smith, J C

    2000-03-01

    A detailed description of a method for collecting meal and drinking bout patterns for the rat over 24-h preference tests is presented. Both the hardware and software are described for data collection with a 6-s resolution. As an example of the value of knowing the details of ingestive patterns, data are presented describing the meal and drinking bout patterns during daylong preference tests between sucrose or saccharin vs. water. During these two-day tests at each of a wide range of concentrations, the intake of powdered Purina Chow, sucrose and saccharin were observed and quantified into meals or bouts. The analysis allowed for a comparison of sucrose and saccharin ingestion in terms of number of bouts, duration of bouts, rate of licking during bouts, the juxtaposition of eating and drinking and the day/night patterns of intake. Comparisons of drinking during bouts were made with electrophysiological and short-term taste test data. The usefulness of microstructure analysis is discussed.

  11. The impact of kidney transplantation on 24-hour ambulatory blood pressure in end-stage renal disease patients.

    PubMed

    Lee, Myung Hyun; Ko, Kyung Min; Ahn, Seung Won; Bae, Myoung Nam; Choi, Bum Soon; Park, Cheol Whee; Kim, Yong-Soo; Yang, Chul Woo; Chung, Byung Ha

    2015-06-01

    In this study, we prospectively investigated the impact of kidney transplantation (KT) on the status of hypertension, including circadian rhythm in end-stage renal disease (ESRD) patients. We performed 24-hour ambulatory blood pressure (BP) monitoring and office BP measurement in 48 patients before and 1 year after KT. According to the nocturnal reduction in systolic BP (ΔSBP), the patients were divided into dippers, non-dippers, and reverse dippers. After KT, the mean BP value in office BP and 24-hour ambulatory BP monitoring did not change, but the proportion of patients taking anti-hypertensive drugs and the pill number significantly decreased. In contrast, the mean ΔSBP significantly decreased, and the proportion of non-dippers and reverse dippers did not decrease. Decrease in ΔSBP after KT was associated with inferior allograft function during follow-up. Our study suggests that KT improved the overall BP level, but it did not affect abnormal circadian rhythm in ESRD patients. PMID:26051924

  12. Transcranial Direct Current Stimulation Augments Perceptual Sensitivity and 24-Hour Retention in a Complex Threat Detection Task

    PubMed Central

    Falcone, Brian; Coffman, Brian A.; Clark, Vincent P.; Parasuraman, Raja

    2012-01-01

    We have previously shown that transcranial direct current stimulation (tDCS) improved performance of a complex visual perceptual learning task (Clark et al. 2012). However, it is not known whether tDCS can enhance perceptual sensitivity independently of non-specific, arousal-linked changes in response bias, nor whether any such sensitivity benefit can be retained over time. We examined the influence of stimulation of the right inferior frontal cortex using tDCS on perceptual learning and retention in 37 healthy participants, using signal detection theory to distinguish effects on perceptual sensitivity (d′) from response bias (ß). Anodal stimulation with 2 mA increased d′, compared to a 0.1 mA sham stimulation control, with no effect on ß. On completion of training, participants in the active stimulation group had more than double the perceptual sensitivity of the control group. Furthermore, the performance enhancement was maintained for 24 hours. The results show that tDCS augments both skill acquisition and retention in a complex detection task and that the benefits are rooted in an improvement in sensitivity (d′), rather than changes in response bias (ß). Stimulation-driven acceleration of learning and its retention over 24 hours may result from increased activation of prefrontal cortical regions that provide top-down attentional control signals to object recognition areas. PMID:22511978

  13. Transcranial direct current stimulation augments perceptual sensitivity and 24-hour retention in a complex threat detection task.

    PubMed

    Falcone, Brian; Coffman, Brian A; Clark, Vincent P; Parasuraman, Raja

    2012-01-01

    We have previously shown that transcranial direct current stimulation (tDCS) improved performance of a complex visual perceptual learning task (Clark et al. 2012). However, it is not known whether tDCS can enhance perceptual sensitivity independently of non-specific, arousal-linked changes in response bias, nor whether any such sensitivity benefit can be retained over time. We examined the influence of stimulation of the right inferior frontal cortex using tDCS on perceptual learning and retention in 37 healthy participants, using signal detection theory to distinguish effects on perceptual sensitivity (d') from response bias (ß). Anodal stimulation with 2 mA increased d', compared to a 0.1 mA sham stimulation control, with no effect on ß. On completion of training, participants in the active stimulation group had more than double the perceptual sensitivity of the control group. Furthermore, the performance enhancement was maintained for 24 hours. The results show that tDCS augments both skill acquisition and retention in a complex detection task and that the benefits are rooted in an improvement in sensitivity (d'), rather than changes in response bias (ß). Stimulation-driven acceleration of learning and its retention over 24 hours may result from increased activation of prefrontal cortical regions that provide top-down attentional control signals to object recognition areas.

  14. Predictors of poor blood pressure control assessed by 24 hour monitoring in patients with type B acute aortic dissection

    PubMed Central

    Delsart, Pascal; Midulla, Marco; Sobocinski, Jonathan; Achere, Charles; Haulon, Stephan; Claisse, Gonzague; Mounier-Vehier, Claire

    2012-01-01

    The chronic management of post-acute aortic dissection (AD) of the descending aorta (Type B) is based on optimal control of blood pressure (BP), with a target BP < 135/80 mmHg. The aim of our study was to determine and verify effective blood pressure control with an objective measurement method and to identify predicting factors. Methods We collected data from 26 patients hospitalized in the acute phase of a Type B AD between 2006 and 2009. Two groups were defined according to 24 hour BP monitoring results at follow-up. Group 1 consisted of patients with a controlled BP (<130/80 mmHg), and Group 2 consisted of patients with an uncontrolled BP. Results Thirty four percent of patients showed an uncontrolled BP at checkup. Vascular history before AD (P = 0.06), high baseline BP trend (P = 0.01 for systolic and P = 0.08 for diastolic), and greater diameter of the descending aorta (P = 0.02) were associated with poor BP control. Conclusion Prognosis after AD is associated with BP control. Therefore, 24 hour BP monitoring can be made. PMID:22272072

  15. Optimum Heart Rate to Minimize Pulsatile External Cardiac Power

    NASA Astrophysics Data System (ADS)

    Pahlevan, Niema; Gharib, Morteza

    2011-11-01

    The workload on the left ventricle is composed of steady and pulsatile components. Clinical investigations have confirmed that an abnormal pulsatile load plays an important role in the pathogenesis of left ventricular hypertrophy (LVH) and progression of LVH to congestive heart failure (CHF). The pulsatile load is the result of the complex dynamics of wave propagation and reflection in the compliant arterial vasculature. We hypothesize that aortic waves can be optimized to reduce the left ventricular (LV) pulsatile load. We used an in-vitro experimental approach to investigate our hypothesis. A unique hydraulic model was used for in-vitro experiments. This model has physical and dynamical properties similar to the heart-aorta system. Different compliant models of the artificial aorta were used to test the hypothesis under various aortic rigidities. Our results indicate that: i) there is an optimum heart rate that minimizes LV pulsatile power (this is in agreement with our previous computational study); ii) introducing an extra reflection site at the specific location along the aorta creates constructive wave conditions that reduce the LV pulsatile power.

  16. Circadian blood pressure and heart rate rhythms in mice.

    PubMed

    Li, P; Sur, S H; Mistlberger, R E; Morris, M

    1999-02-01

    The circadian pattern of mean arterial pressure (MAP) and heart rate (HR) was measured in C57BL mice with carotid arterial catheters. Cardiovascular parameters were recorded continuously with a computerized monitoring system at a sampling rate of 100 Hz. The tethered animals were healthy, showing stabilized drinking and eating patterns within 2 days of surgery and little loss of body weight. Analysis of the 24-h pattern of MAP and HR was conducted using data from 3-6 consecutive days of recording. A daily rhythm of MAP was evident in all mice, with group mean dark and light values of 101.4 +/- 7.3 and 93.1 +/- 2.9 mmHg, respectively. The group mean waveform was bimodal, with peak values evident early and late in the dark period, and a trough during the middle of the light period. The phase of maximum and minimum values showed low within-group variance. Mean heart rate was greater at night than during the day (561.9 +/- 22.7 vs. 530.3 +/- 22.3 beats/min). Peak values generally occurred at dark onset, and minimum values during the middle of both the dark and the light periods. We conclude that it is possible to perform measurements of circadian cardiovascular parameters in the mouse, providing new avenues for the investigation of genetic models.

  17. Heart rate variability biofeedback: how and why does it work?

    PubMed Central

    Lehrer, Paul M.; Gevirtz, Richard

    2014-01-01

    In recent years there has been substantial support for heart rate variability biofeedback (HRVB) as a treatment for a variety of disorders and for performance enhancement (Gevirtz, 2013). Since conditions as widely varied as asthma and depression seem to respond to this form of cardiorespiratory feedback training, the issue of possible mechanisms becomes more salient. The most supported possible mechanism is the strengthening of homeostasis in the baroreceptor (Vaschillo et al., 2002; Lehrer et al., 2003). Recently, the effect on the vagal afferent pathway to the frontal cortical areas has been proposed. In this article, we review these and other possible mechanisms that might explain the positive effects of HRVB. PMID:25101026

  18. Heart rate and estimated energy expenditure during ballroom dancing.

    PubMed Central

    Blanksby, B A; Reidy, P W

    1988-01-01

    Ten competitive ballroom dance couples performed simulated competitive sequences of Modern and Latin American dance. Heart rate was telemetered during the dance sequences and related to direct measures of oxygen uptake and heart rate obtained while walking on a treadmill. Linear regression was employed to estimate gross and net energy expenditures of the dance sequences. A multivariate analysis of variance with repeated measures on the dance factor was applied to the data to test for interaction and main effects on the sex and dance factors. Overall mean heart rate values for the Modern dance sequence were 170 beats.min-1 and 173 beats.min-1 for males and females respectively. During the Latin American sequence mean overall heart rate for males was 168 beats.min-1 and 177 beats.min-1 for females. Predicted mean gross values of oxygen consumption for the males were 42.8 +/- 5.7 ml.kg-1 min-1 and 42.8 +/- 6.9 ml.kg-1 min-1 for the Modern and Latin American sequences respectively. Corresponding gross estimates of oxygen consumption for the females were 34.7 +/- 3.8 ml.kg-1 min-1 and 36.1 +/- 4.1 ml.kg-1 min-1. Males were estimated to expand 54.1 +/- 8.1 kJ.min-1 of energy during the Modern sequence and 54.0 +/- 9.6 kJ.min-1 during the Latin American sequence, while predicted energy expenditure for females was 34.7 +/- 3.8 kJ.min-1 and 36.1 +/- 4.1 kJ.min-1 for Modern and Latin American dance respectively. The results suggested that both males and females were dancing at greater than 80% of their maximum oxygen consumption. A significant difference between males and females was observed for predicted gross and net values of oxygen consumption (in L.min-1 and ml.kg-1 min-1). PMID:3167503

  19. Making the Most of the "Daphnia" Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine

    ERIC Educational Resources Information Center

    Corotto, Frank; Ceballos, Darrel; Lee, Adam; Vinson, Lindsey

    2010-01-01

    Students commonly test the effects of chemical agents on the heart rate of the crustacean "Daphnia" magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in "Daphnia." Ethanol at 5% and 10% (v/v) reduced mean heart rate to…

  20. Heart Rates of High School Physical Education Students during Team Sports, Individual Sports, and Fitness Activities

    ERIC Educational Resources Information Center

    Laurson, Kelly R.; Brown, Dale D.; Cullen, Robert W.; Dennis, Karen K.

    2008-01-01

    This study examined how activity type influenced heart rates and time spent in target heart rate zones of high school students participating in physical education classes. Significantly higher average heart rates existed for fitness (142 plus or minus 24 beats per minute [bpm]) compared to team (118 plus or minus 24 bpm) or individual (114 plus or…

  1. Comparison of Traditional and Alternative Fitness Teaching Formats on Heart Rate Intensity and Perceived Enjoyment.

    ERIC Educational Resources Information Center

    Ha, Amy Sau-ching; Heung-Sang Wong, Stephen

    2002-01-01

    Compared a traditional and an alternative (skill-fitness- music) fitness teaching format to determine whether there would be differences on Hong Kong middle school students' heart rate intensity and perceived enjoyment. Data from heart rate monitors and student surveys indicated that the two formats did not produce differences in heart rates.…

  2. The Relationship between Heart Rate Reserve and Oxygen Uptake Reserve in Children and Adolescents

    ERIC Educational Resources Information Center

    Hui, Stanley Sai-chuen; Chan, Janus Wan-sze

    2006-01-01

    The purpose of the present study was to examine the relationship between oxygen uptake (VO[subscript 2]) and heart rate (HR) responses during rest and exercise in Chinese children and youth and to evaluate the relationships between maximal heart rate (%HRmax), heart rate reserve (%HRR), peak oxygen uptake (%VO[subscript 2]peak), and oxygen uptake…

  3. 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.

  4. Heart Rate and Lactate Levels during Weight-Training Exercise in Trained and Untrained Men.

    ERIC Educational Resources Information Center

    Stone, Michael H.; And Others

    1987-01-01

    A study of effects of squatting exercise on heart rate and blood lactate levels in trained and untrained males indicated that trained subjects performed more work and had higher heart rates and lactate levels at exhaustion untrained subjects, though heart rate and lactate levels were lower for trained subjects at a given bar mass or submaximal…

  5. 24-hour urine protein

    MedlinePlus

    ... a blockage of blood vessels, or other causes Multiple myeloma Healthy people may have higher than normal urine ... Distal Hemolytic anemia Macroglobulinemia of Waldenstrom Microalbuminuria test Multiple myeloma Nephrotic syndrome Proximal Wilson disease Update Date 11/ ...

  6. Urine 24-hour volume

    MedlinePlus

    ... in a day, such as: Creatinine Sodium Potassium Nitrogen Protein This test may also be done if ... disease Potassium urine test Sodium urine test Urea nitrogen urine test Urination - excessive amount Urine output - decreased ...

  7. Mercury Exposure and Heart Rate Variability: A Systematic Review

    PubMed Central

    Gribble, Matthew O.; Cheng, Alan; Berger, Ronald D.; Rosman, Lori; Guallar, Eliseo

    2015-01-01

    Background Mercury affects the nervous system and has been implicated in altering heart rhythm and function. We sought to better define its role in modulating heart rate variability, a well-known marker of cardiac autonomic function. Design Systematic review. Methods We searched PubMed, Embase, TOXLINE and DART databases without language restriction. We report findings as a qualitative systematic review because heterogeneity in study design and assessment of exposures and outcomes across studies, as well as other methodological limitations of the literature, precluded a quantitative meta-analysis. Results We identified 12 studies of mercury exposure and heart rate variability in human populations (10 studies involving primarily environmental methylmercury exposure and two studies involving occupational exposure to inorganic mercury) conducted in Japan, the Faroe Islands, Canada, Korea, French Polynesia, Finland and Egypt. The association of prenatal mercury exposure with lower high-frequency band scores (thought to reflect parasympathetic activity) in several studies, in particular the inverse association of cord blood mercury levels with the coefficient of variation of the R-R intervals and with low frequency and high frequency bands at 14 years of age in the Faroe Islands birth cohort study, suggests that early mercury exposure could have a long-lasting effect on cardiac parasympathetic activity. Studies with later environmental exposures to mercury in children or in adults were heterogeneous and did not show consistent associations. Conclusions The evidence was too limited to draw firm causal inferences. Additional research is needed to elucidate the effects of mercury on cardiac autonomic function, particularly as early-life exposures might have lasting impacts on cardiac parasympathetic function. PMID:26231507

  8. Deletion of neurturin impairs development of cholinergic nerves and heart rate control in postnatal mouse hearts.

    PubMed

    Downs, Anthony M; Jalloh, Hawa B; Prater, Kayla J; Fregoso, Santiago P; Bond, Cherie E; Hampton, Thomas G; Hoover, Donald B

    2016-05-01

    The neurotrophic factor neurturin is required for normal cholinergic innervation of adult mouse heart and bradycardic responses to vagal stimulation. Our goals were to determine effects of neurturin deletion on development of cardiac chronotropic and dromotropic functions, vagal baroreflex response, and cholinergic nerve density in nodal regions of postnatal mice. Experiments were performed on postnatal C57BL/6 wild-type (WT) and neurturin knockout (KO) mice. Serial electrocardiograms were recorded noninvasively from conscious pups using an ECGenie apparatus. Mice were treated with atenolol to evaluate and block sympathetic effects on heart rate (HR) and phenylephrine (PE) to stimulate the baroreflex. Immunohistochemistry was used to label cholinergic nerves in paraffin sections. WT and KO mice showed similar age-dependent increases in HR and decreases in PR interval between postnatal days (P) 2.5 and 21. Treatment with atenolol reduced HR significantly in WT and KO pups at P7.5. PE caused a reflex bradycardia that was significantly smaller in KO pups. Cholinergic nerve density was significantly less in nodal regions of P7.5 KO mice. We conclude that cholinergic nerves have minimal influence on developmental changes in HR and PR, QRS, and QTc intervals in mouse pups. However, cholinergic nerves mediate reflex bradycardia by 1 week postnatally. Deletion of neurturin impairs cholinergic innervation of the heart and the vagal efferent component of the baroreflex early during postnatal development.

  9. Heart rate effects of intraosseous injections using slow and fast rates of anesthetic solution deposition.

    PubMed

    Susi, Louis; Reader, Al; Nusstein, John; Beck, Mike; Weaver, Joel; Drum, Melissa

    2008-01-01

    The authors, using a crossover design, randomly administered, in a single-blind manner, 3 primary intraosseous injections to 61 subjects using: the Wand local anesthetic system at a deposition rate of 45 seconds (fast injection); the Wand local anesthetic system at a deposition rate of 4 minutes and 45 seconds (slow injection); a conventional syringe injection at a deposition rate of 4 minutes and 45 seconds (slow injection), in 3 separate appointments spaced at least 3 weeks apart. A pulse oximeter measured heart rate (pulse). The results demonstrated the mean maximum heart rate was statistically higher with the fast intraosseous injection (average 21 to 28 beats/min increase) than either of the 2 slow intraosseous injections (average 10 to 12 beats/min increase). There was no statistically significant difference between the 2 slow injections. We concluded that an intraosseous injection of 1.4 mL of 2% lidocaine with 1 : 100,000 epinephrine with the Wand at a 45-second rate of anesthetic deposition resulted in a significantly higher heart rate when compared with a 4-minute and 45-second anesthetic solution deposition using either the Wand or traditional syringe.

  10. Heart-rate variability and precompetitive anxiety in swimmers.

    PubMed

    Cervantes Blásquez, Julio César; Rodas Font, Gil; Capdevila Ortís, Lluís

    2009-11-01

    The aim of this study was to test the utility of heart-rate variability (HRV) analyses as a noninvasive means of quantifying cardiac autonomic regulation during precompetitive anxiety situations in swimmers. Psychophysiological state evaluation of 10 volunteer swimmers (6 women and 4 men) was obtained by comparing baseline training condition (TC) with competition condition (CC). Self-evaluation of precompetitive somatic anxiety measured by CSAI-2 showed significant increase from the TC to CC. Analysis showed that during higher precompetitive anxiety level, a significant reduction in the timing (RMSSD), frequency (HFms2 and HFnu) and Poincaré plot (SD1) of heart-rate variability was observed, and a significant increase in the low frequency to high frequency ratio (LF/HF %). The results indicate a shift towards sympathetic predominance as a result of parasympathetic withdrawal. Our results provide an HRV analysis in a valid, useful and non-invasive way to evaluate the change of sympathovagal balance in presence of precompetitive stress.

  11. Heart rate variability (HRV) during virtual reality immersion.

    PubMed

    Malińska, Marzena; Zużewicz, Krystyna; Bugajska, Joanna; Grabowski, Andrzej

    2015-01-01

    The goal of the study was assessment of the hour-long training involving handling virtual environment (sVR) and watching a stereoscopic 3D movie on the mechanisms of autonomic heart rate (HR) regulation among the subjects who were not predisposed to motion sickness. In order to exclude predispositions to motion sickness, all the participants (n=19) underwent a Coriolis test. During an exposure to 3D and sVR the ECG signal was continuously recorded using the Holter method. For the twelve consecutive 5-min epochs of ECG signal, the analysis of heart rate variability (HRV) in time and frequency domains was conducted. After 30 min from the beginning of the training in handling the virtual workstation a significant increase in LF spectral power was noted. The values of the sympathovagal LF/HF index while sVR indicated a significant increase in sympathetic predominance in four time intervals, namely between the 5th and the 10th minute, between the 15th and the 20th minute, between the 35th and 40th minute and between the 55th and the 60th minute of exposure.

  12. Abnormal intermittency of heart rate in patients with neurocardiogenic syncope

    NASA Astrophysics Data System (ADS)

    Yum, Myung-Kul; Kim, Kyung-Sik; Kim, June-Soo

    2002-03-01

    Introduction: We aim to test our hypothesis that, during daily activity, though not as prominent as during HUT test, the patients may show different degree of intermittency in heart rates compared to healthy persons. METHOD AND RESULTS: Thirty patients with neurocardiogenic syncope who showed a positive HUT test and thirty healthy controls without history of syncope were included. Their twenty-four hour ambulatory electrocardiograms were digitized and RR interval (RRI) data of six-hour interval were analyzed. To quantify the intermittency (C1) behavior, The intermittency analysis was performed using Mexican hat wavelet. For the syncope group, the values of C1 were significantly higher at 6AM-6PM and lower at 6AM-midnight, respectively. However, the values were not different at midnight-6AM. The significant night-day circadian change shown in the control group was lost in C1. CONCLUSION: When compared to healthy control, the patients with neurocardiogenic syncope shows increased intermittency of heart rates in daytime during daily activity, and abnormal circadian rhythms of the index. These new findings may be useful for investigating the pathophysiology of neurocardiogenic syncope and early identification of the patients.

  13. Human heart rate variability relation is unchanged during motion sickness

    NASA Technical Reports Server (NTRS)

    Mullen, T. J.; Berger, R. D.; Oman, C. M.; Cohen, R. J.

    1998-01-01

    In a study of 18 human subjects, we applied a new technique, estimation of the transfer function between instantaneous lung volume (ILV) and instantaneous heart rate (HR), to assess autonomic activity during motion sickness. Two control recordings of ILV and electrocardiogram (ECG) were made prior to the development of motion sickness. During the first, subjects were seated motionless, and during the second they were seated rotating sinusoidally about an earth vertical axis. Subjects then wore prism goggles that reverse the left-right visual field and performed manual tasks until they developed moderate motion sickness. Finally, ILV and ECG were recorded while subjects maintained a relatively constant level of sickness by intermittent eye closure during rotation with the goggles. Based on analyses of ILV to HR transfer functions from the three conditions, we were unable to demonstrate a change in autonomic control of heart rate due to rotation alone or due to motion sickness. These findings do not support the notion that moderate motion sickness is manifested as a generalized autonomic response.

  14. Heart rate variability (HRV) during virtual reality immersion

    PubMed Central

    Malińska, Marzena; Zużewicz, Krystyna; Bugajska, Joanna; Grabowski, Andrzej

    2015-01-01

    The goal of the study was assessment of the hour-long training involving handling virtual environment (sVR) and watching a stereoscopic 3D movie on the mechanisms of autonomic heart rate (HR) regulation among the subjects who were not predisposed to motion sickness. In order to exclude predispositions to motion sickness, all the participants (n=19) underwent a Coriolis test. During an exposure to 3D and sVR the ECG signal was continuously recorded using the Holter method. For the twelve consecutive 5-min epochs of ECG signal, the analysis of heart rate variability (HRV) in time and frequency domains was conducted. After 30 min from the beginning of the training in handling the virtual workstation a significant increase in LF spectral power was noted. The values of the sympathovagal LF/HF index while sVR indicated a significant increase in sympathetic predominance in four time intervals, namely between the 5th and the 10th minute, between the 15th and the 20th minute, between the 35th and 40th minute and between the 55th and the 60th minute of exposure. PMID:26327262

  15. Motion-compensated non-contact detection of heart rate

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Liu, Ming; Dong, Liquan; Zhao, Yuejin; Liu, Xiaohua

    2015-12-01

    A new non-contact heart rate detection method based on the dual-wavelength technique is proposed and demonstrated experimentally. It is a well-known fact that the differences in the circuits of two detection modules result in different responses of two modules for motion artifacts. This poses a great challenge to compensate the motion artifacts during measurements. In order to circumvent this problem, we have proposed the amplitude spectrum and phase spectrum adaptive filter. Comparing with the time-domain adaptive filter and independent component analysis, the amplitude spectrum and phase spectrum adaptive filter can suppress the interference caused by the two circuit differences and effectively compensate the motion artifacts. To make the device is much compact and portable, a photoelectric probe is designed. The measurement distance is from several centimeters up to several meters. Moreover, the data obtained by using this non-contact detection system is compared with those of the conventional finger blood volume pulse (BVP) sensor by simultaneously measuring the heart rate of the subject. The data obtained from the proposed non-contact system are consistent and comparable with that of the BVP sensor.

  16. Heart rate monitoring and control in altered gravity conditions.

    PubMed

    Di Rienzo, M; Parati, G; Rizzo, F; Meriggi, P; Merati, G; Faini, A; Castiglioni, P

    2007-01-01

    On the basis of indirect evidences it has been hypothesized that during space missions the almost complete absence of gravity might impair the baroreflex control of circulation. In the first part of this paper we report results obtained from a series of experiments carried out to directly verify this hypothesis during the 16-day STS 107 Shuttle flight. Spontaneous baroreflex sensitivity was assessed in four astronauts before flight (baseline) and at days 0-1, 6-7 and 12-13 during flight, both at rest and while performing moderate exercise. Our results indicate that at rest the baroreflex sensitivity significantly increased in the early flight phase, as compared to pre-flight values and tended to return to baseline in the mid-late phase of flight. During exercise, baroreflex sensitivity was lower than at rest, without any difference among pre-flight and in-flight values. These findings seem to exclude the hypothesis of an impairment of the baroreflex control of heart rate during exposure to microgravity, at least over a time window of 16 days. In the second part of the paper we propose a novel textile-based methodology for heart rate and other vital signs monitoring during gravity stress. The positive results obtained from its use during parachute jumps support the use of smart garments for the unobtrusive assessment of physiological parameters in extreme environments. PMID:18003559

  17. Heart rate variability in children with type 1 diabetes mellitus

    PubMed Central

    Gardim, Camila Balsamo; de Oliveira, Bruno Affonso P.; Bernardo, Aline Fernanda B.; Gomes, Rayana Loch; Pacagnelli, Francis Lopes; Lorençoni, Roselene Modolo R.; Vanderlei, Luiz Carlos M.

    2014-01-01

    OBJECTIVE: To gather current information about the effects of type 1 diabetes mellitus on children's cardiac autonomic behavior. DATA SOURCES: The search of articles was conducted on PubMed, Ibecs, Medline, Cochrane, Lilacs, SciELO and PEDro databases using the MeSH terms: "autonomic nervous system", "diabetes mellitus", "child", "type 1 diabetes mellitus", "sympathetic nervous system" and "parasympathetic nervous system", and their respective versions in Portuguese (DeCS). Articles published from January 2003 to February 2013 that enrolled children with 9-12 years old with type 1 diabetes mellitus were included in the review. DATA SYNTHESIS: The electronic search resulted in four articles that approached the heart rate variability in children with type 1 diabetes mellitus, showing that, in general, these children present decreased global heart rate variability and vagal activity. The practice of physical activity promoted benefits for these individuals. CONCLUSIONS: Children with type 1 diabetes mellitus present changes on autonomic modulation, indicating the need for early attention to avoid future complications in this group. PMID:25119762

  18. Heart rate variability (HRV) during virtual reality immersion.

    PubMed

    Malińska, Marzena; Zużewicz, Krystyna; Bugajska, Joanna; Grabowski, Andrzej

    2015-01-01

    The goal of the study was assessment of the hour-long training involving handling virtual environment (sVR) and watching a stereoscopic 3D movie on the mechanisms of autonomic heart rate (HR) regulation among the subjects who were not predisposed to motion sickness. In order to exclude predispositions to motion sickness, all the participants (n=19) underwent a Coriolis test. During an exposure to 3D and sVR the ECG signal was continuously recorded using the Holter method. For the twelve consecutive 5-min epochs of ECG signal, the analysis of heart rate variability (HRV) in time and frequency domains was conducted. After 30 min from the beginning of the training in handling the virtual workstation a significant increase in LF spectral power was noted. The values of the sympathovagal LF/HF index while sVR indicated a significant increase in sympathetic predominance in four time intervals, namely between the 5th and the 10th minute, between the 15th and the 20th minute, between the 35th and 40th minute and between the 55th and the 60th minute of exposure. PMID:26327262

  19. High frequency chest compression effects heart rate variability.

    PubMed

    Lee, Jongwon; Lee, Yong W; Warwick, Warren J

    2007-01-01

    High frequency chest compression (HFCC) supplies a sequence of air pulses through a jacket worn by a patient to remove excessive mucus for the treatment or prevention of lung disease patients. The air pulses produced from the pulse generator propagates over the thorax delivering the vibration and compression energy. A number of studies have demonstrated that the HFCC system increases the ability to clear mucus and improves lung function. Few studies have examined the change in instantaneous heart rate (iHR) and heart rate variability (HRV) during the HFCC therapy. The purpose of this study is to measure the change of HRV with four experimental protocols: (a) without HFCC, (b) during Inflated, (c)HFCC at 6Hz, and (d) HFCC at 21Hz. The nonlinearity and regularity of HRV was assessed by approximate entropy (ApEn), a method used to quantify the complexities and randomness. To compute the ApEn, we sectioned with a total of eight epochs and displayed the ApEn over the each epoch. Our results show significant differences in the both the iHR and HRV between the experimental protocols. The iHR was elevated at both the (c) 6Hz and (d) 21Hz condition from without HFCC (10%, 16%, respectively). We also found that the HFCC system tends to increase the HRV. Our study suggests that monitoring iHR and HRV are very important physiological indexes during HFCC therapy.

  20. Effects of Vibration and G-Loading on Heart Rate, Breathing Rate, and Response Time

    NASA Technical Reports Server (NTRS)

    Godinez, Angelica; Ayzenberg, Ruthie; Liston, Dorian B.; Stone, Leland S.

    2013-01-01

    Aerospace and applied environments commonly expose pilots and astronauts to G-loading and vibration, alone and in combination, with well-known sensorimotor (Cohen, 1970) and performance consequences (Adelstein et al., 2008). Physiological variables such as heart rate (HR) and breathing rate (BR) have been shown to increase with G-loading (Yajima et al., 1994) and vibration (e.g. Guignard, 1965, 1985) alone. To examine the effects of G-loading and vibration, alone and in combination, we measured heart rate and breathing rate under aerospace-relevant conditions (G-loads of 1 Gx and 3.8 Gx; vibration of 0.5 gx at 8, 12, and 16 Hz).

  1. 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

  2. Puerperal endometritis and intrauterine fetal heart rate monitoring.

    PubMed

    Rehu, M; Haukkamaa, M

    1980-08-01

    The incidence of puerperal endometritis in 5058 patients who were delivered during a one year study period was recorded prospectively. Caesarean section was performed in 774 cases (15.3%) and intrauterine fetal heart rate monitoring was used in 2016 cases (39.9%). After vaginal delivery, the incidence of endometritis was 1.5% in those monitored externally and 2.4% in those monitored internally (P less than 0.05). After Caesarean section, endometritis occurred in 8.0% of those monitored externally and in 16.4% of those monitored internally for varying times (P less than 0.01). The duration of monitoring had no significant effect on these infection rates. The risk of puerperal endometritis after internal fetal monitoring seemed to be the same as after one vaginal examination. PMID:7259077

  3. Contact-free heart rate measurement using multiple video data

    NASA Astrophysics Data System (ADS)

    Hung, Pang-Chan; Lee, Kual-Zheng; Tsai, Luo-Wei

    2013-10-01

    In this paper, we propose a contact-free heart rate measurement method by analyzing sequential images of multiple video data. In the proposed method, skin-like pixels are firstly detected from multiple video data for extracting the color features. These color features are synchronized and analyzed by independent component analysis. A representative component is finally selected among these independent component candidates to measure the HR, which achieves under 2% deviation on average compared with a pulse oximeter in the controllable environment. The advantages of the proposed method include: 1) it uses low cost and high accessibility camera device; 2) it eases users' discomfort by utilizing contact-free measurement; and 3) it achieves the low error rate and the high stability by integrating multiple video data.

  4. How to avoid misinterpretation of heart rate variability power spectra?

    PubMed

    Cammann, Henning; Michel, Josef

    2002-04-01

    Spectral analysis of R-R Interval time series is increasingly used to determine periodic components of heart rate variability (HRV). Particular diagnostic relevance is assigned to a low-frequency (LF) component, associated with blood pressure regulation, and a high-frequency (HF) component, also referred to as respiratory sinus arrhythmia (RSA) in the HRV power spectra. Frequency ranges for parametrisation of power spectra have been defined for either component in numerous publications.Results obtained from examinations with standardised psychic load in which ECG and respiratory signal are continuously recorded and adequately processed have shown that the true individual frequency range of the HF component can be reliably determined only by means of characteristics of respiration (respiratory rate (RR), range and median value of RR, tidal depth). Respiratory rhythms are interindividually extremely differentiated and of individual-specific nature. In many cases LF and HF components may be totally superimposed on each other and, consequently, cannot be diagnostically evaluated.

  5. Ultra-Rapid dUT1 Measurements on Japan-Fennoscandian Baselines - Application to 24-hour Sessions

    NASA Technical Reports Server (NTRS)

    Matsuzaka, Shigeru; Kurihara, Shinobu; Sekido, Mamoru; Hobiger, Thomas; Haas, Rudiger; Ritakari, Jouko; Wagner, Jan

    2010-01-01

    GSI, NICT, OSO, and MRO have been engaged in Ultra-rapid dUT1 experiments since 2007 aiming at the technological possibility of real-time dUT1 results using the e-VLBI technique. We have already successfully determined dUT1 in less than four minutes after the end of an experimental Intensive session in 2008, and at present we routinely get the results within 30 minutes for regular Intensives. In 2009 we applied the technique to 24-hour sessions and continuously obtained dUT1 values by processing and analyzing Tsukuba Onsala data in near real-time. It showed a detailed behavior of UT1 variations, which could be very valuable for scientific study as well as for precise prediction of UT1-UTC.

  6. A role for BK channels in heart rate regulation in rodents.

    PubMed

    Imlach, Wendy L; Finch, Sarah C; Miller, John H; Meredith, Andrea L; Dalziel, Julie E

    2010-01-14

    The heart generates and propagates action potentials through synchronized activation of ion channels allowing inward Na(+) and Ca(2+) and outward K(+) currents. There are a number of K(+) channel types expressed in the heart that play key roles in regulating the cardiac cycle. Large conductance calcium-activated potassium (BK) ion channels are not thought to be directly involved in heart function. Here we present evidence that heart rate can be significantly reduced by inhibiting the activity of BK channels. Agents that specifically inhibit BK channel activity, including paxilline and lolitrem B, slowed heart rate in conscious wild-type mice by 30% and 42%, respectively. Heart rate of BK channel knock-out mice (Kcnma1(-/-)) was not affected by these BK channel inhibitors, suggesting that the changes to heart rate were specifically mediated through BK channels. The possibility that these effects were mediated through BK channels peripheral to the heart was ruled out with experiments using isolated, perfused rat hearts, which showed a significant reduction in heart rate when treated with the BK channel inhibitors paxilline (1 microM), lolitrem B (1 microM), and iberiotoxin (0.23 microM), of 34%, 60%, and 42%, respectively. Furthermore, paxilline was shown to decrease heart rate in a dose-dependent manner. These results implicate BK channels located in the heart to be directly involved in the regulation of heart rate.

  7. Hierarchical Structure of Heart Rate Variability in Humans

    NASA Astrophysics Data System (ADS)

    Gao, X. Z.; Ching, E. S. C.; Lin, D. C.

    2004-03-01

    We show a hierarchical structure (HS) of the She-Leveque form in the beat-to-beat RR intervals of heart rate variability (HRV) in humans. This structure, first found as an empirical law in turbulent fluid flows, implies further details in the HRV multifractal scaling. We tested HS using daytime RRi data from healthy subjects and heart diseased patients with congestive heart failure and found a universal law C(b) where b characterizes the multifractality of HRV and C is related to a co-dimension parameter of the most violent events in the fluctuation. The potential of diagnosis is discussed based on the characteristics of this finding. To model the HRV phenomenology, we propose a local-feedback-global-cascade (LFGC) model based on the She-Waymire (SW) cascade solution to the HS in fluid turbulence. This model extends from the previous work in that it integrates additive law multiplicatively into the cascade structure. It is an attempt to relate to the cardiovascular physiology which consists of numerous feedback controls that function primarily on the principle of additive law. In particular, the model is based on the same philosophy as the SW cascade that its multifractal dynamics consists of a singular and a modulating component. In the LFGC model, we introduce local feedback to model the dynamics of the modulating effect. The novelty of our model is to incorporate the cascade structure in the scheduling for the feedback control. This model also represents an alternative solution to the HS. We will present the simulation results by the LFGC model and discuss its implication in physiology terms.

  8. Heart rates increase after hatching in two species of natricine snakes

    PubMed Central

    Aubret, Fabien

    2013-01-01

    Experimental studies have shown heart rates to decrease from embryo to hatchling stage in turtles, remain steady in skinks, and increase in birds. However, no snake species has been studied in this regard. I recorded heart rate evolution trajectories from embryo to juvenile stage in 78 eggs from two species of European Natricine snakes. Unexpectedly, snakes behaved more like birds than turtles or lizards: heart rates increased after hatching in both N. maura and N. natrix, respectively by 43.92 ± 22.84% and 35.92 ± 24.52%. Heart rate shift was not related to an abrupt elevation of metabolism per se (snakes that increased their heart rates the most sharply grew the least after birth), but rather due to a number of smaller eggs that experienced lower than normal heart rates throughout the incubation and recovered a normal heart rate post-birth. This finding is discussed in the light of hatching synchrony benefits. PMID:24287712

  9. Heart rates increase after hatching in two species of Natricine snakes.

    PubMed

    Aubret, Fabien

    2013-11-29

    Experimental studies have shown heart rates to decrease from embryo to hatchling stage in turtles, remain steady in skinks, and increase in birds. However, no snake species has been studied in this regard. I recorded heart rate evolution trajectories from embryo to juvenile stage in 78 eggs from two species of European Natricine snakes. Unexpectedly, snakes behaved more like birds than turtles or lizards: heart rates increased after hatching in both N. maura and N. natrix, respectively by 43.92 ± 22.84% and 35.92 ± 24.52%. Heart rate shift was not related to an abrupt elevation of metabolism per se (snakes that increased their heart rates the most sharply grew the least after birth), but rather due to a number of smaller eggs that experienced lower than normal heart rates throughout the incubation and recovered a normal heart rate post-birth. This finding is discussed in the light of hatching synchrony benefits.

  10. Electrocardiogram, heart movement and heart rate in the awake gecko (Hemidactylus mabouia).

    PubMed

    Germer, Carina M; Tomaz, Juliana M; Carvalho, Ana F; Bassani, Rosana A; Bassani, José W M

    2015-01-01

    The electrocardiogram (ECG) is the simplest and most effective non-invasive method to assess the electrical activity of the heart and to obtain information on the heart rate (HR) and rhythm. Because information on the HR of very small reptiles (body mass <10 g) is still scarce in the literature, in the present work we describe a procedure for recording the ECG in non-anesthetized geckos (Hemidactylus mabouia, Moreau de Jonnès, 1818) under different conditions, namely manual restraint (MR), spontaneous tonic immobility (TI), and in the non-restrained condition (NR). In the gecko ECG, the P, QRS and T waves were clearly distinguishable. The HR was 2.83 ± 0.02 Hz under MR, which was significantly greater (p < 0.001) than the HR under the TI (1.65 ± 0.09 Hz) and NR (1.60 ± 0.10 Hz) conditions. Spontaneously beating isolated gecko hearts contracted at 0.84 ± 0.03 Hz. The in vitro beating rate was affected in a concentration-dependent fashion by adrenoceptor stimulation with noradrenaline, as well as by the muscarinic cholinergic agonist carbachol, which produced significant positive and negative chronotropic effects, respectively (p < 0.001). To our knowledge, this is the first report on the ECG morphology and HR values in geckos, particularly under TI. The methodology and instrumentation developed here are useful for non-invasive in vivo physiological and pharmacological studies in small reptiles without the need of physical restraint or anesthesia.

  11. Unobtrusive heart rate monitor based on a fiber specklegram sensor and a single-board computer

    NASA Astrophysics Data System (ADS)

    Benevides, Alessandro B.; Frizera, Anselmo; Cotrina, Anibal; Ribeiro, Moisés. R. N.; Segatto, Marcelo E. V.; Pontes, Maria José

    2015-09-01

    This paper proposes a portable and unobtrusive heart rate monitor based on fiber specklegram sensors. The proposed module uses the Raspberry Pi module to perform the image acquisition and the fiber specklegram sensor, which is based on multimode plastic optical fibers. The heart rate is obtained by welch power spectral density estimate and the heart beats are identified by means of a threshold analysis.

  12. Problem Behavior and Heart Rate Reactivity in Adopted Adolescents: Longitudinal and Concurrent Relations

    ERIC Educational Resources Information Center

    Bimmel, Nicole; van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Juffer, Femmie; De Geus, Eco J. C.

    2008-01-01

    The present longitudinal study examined resting heart rate and heart rate variability and reactivity to a stressful gambling task in adopted adolescents with aggressive, delinquent, or internalizing behavior problems and adopted adolescents without behavior problems (total N=151). Early-onset delinquent adolescents showed heart rate…

  13. Comparison of pulse rate variability with heart rate variability during obstructive sleep apnea.

    PubMed

    Khandoker, Ahsan H; Karmakar, Chandan K; Palaniswami, Marimuthu

    2011-03-01

    We investigate whether pulse rate variability (PRV) extracted from finger photo-plethysmography (Pleth) waveforms can be the substitute of heart rate variability (HRV) from RR intervals of ECG signals during obstructive sleep apnea (OSA). Simultaneous measurements (ECG and Pleth) were taken from 29 healthy subjects during normal (undisturbed sleep) breathing and 22 patients with OSA during OSA events. Highly significant (p<0.01) correlations (1.0>r>0.95) were found between heart rate (HR) and pulse rate (PR). Bland-Altman plot of HR and PR shows good agreement (<5% difference). Comparison of 2 min recording epochs demonstrated significant differences (p<0.01) in time, frequency domains and complexity analysis, between normal and OSA events using PRV as well as HRV measures. Results suggest that both HRV and PRV indices could be used to distinguish OSA events from normal breathing during sleep. However, several variability measures (SDNN, RMSSD, HF power, LF/HF and sample entropy) of PR and HR were found to be significantly (p<0.01) different during OSA events. Therefore, we conclude that PRV provides accurate inter-pulse variability to measure heart rate variability under normal breathing in sleep but does not precisely reflect HRV in sleep disordered breathing.

  14. Heart rate variability in risk stratification of cardiac patients.

    PubMed

    Huikuri, Heikki V; Stein, Phyllis K

    2013-01-01

    Heart rate (HR) variability has been extensively studied in cardiac patients, especially in patients surviving an acute myocardial infarction (AMI) and also in patients with congestive heart failure (CHF) or left ventricular (LV) dysfunction. The majority of studies have shown that patients with reduced or abnormal HR variability have an increased risk of mortality within a few years after an AMI or after a diagnosis of CHF/LV dysfunction. Various measures of HR dynamics, such as time-domain, spectral, and non-linear measures of HR variability have been used in risk stratification. The prognostic power of various measures, except of those reflecting rapid R-R interval oscillations, has been almost identical, albeit some non-linear HR variability measures, such as short-term fractal scaling exponent have provided somewhat better prognostic information than the others. Abnormal HR variability predicts both sudden and non-sudden cardiac death. Because of remodeling of the arrhythmia substrate after AMI, early measurement of HR variability to identify those at high risk should likely be repeated later in order to assess the risk of fatal arrhythmia events. Future randomized trials using HR variability/turbulence as one of the pre-defined inclusion criteria will show whether routine measurement of HR variability/turbulence will become a routine clinical tool for risk stratification of cardiac patients.

  15. Resting high frequency heart rate variability selectively predicts cooperative behavior.

    PubMed

    Beffara, Brice; Bret, Amélie G; Vermeulen, Nicolas; Mermillod, Martial

    2016-10-01

    This study explores whether the vagal connection between the heart and the brain is involved in prosocial behaviors. The Polyvagal Theory postulates that vagal activity underlies prosocial tendencies. Even if several results suggest that vagal activity is associated with prosocial behaviors, none of them used behavioral measures of prosociality to establish this relationship. We recorded the resting state vagal activity (reflected by High Frequency Heart Rate Variability, HF-HRV) of 48 (42 suitale for analysis) healthy human adults and measured their level of cooperation during a hawk-dove game. We also manipulated the consequence of mutual defection in the hawk-dove game (severe vs. moderate). Results show that HF-HRV is positively and linearly related to cooperation level, but only when the consequence of mutual defection is severe (compared to moderate). This supports that i) prosocial behaviors are likely to be underpinned by vagal functioning ii) physiological disposition to cooperate interacts with environmental context. We discuss these results within the theoretical framework of the Polyvagal Theory. PMID:27343804

  16. Resting high frequency heart rate variability selectively predicts cooperative behavior.

    PubMed

    Beffara, Brice; Bret, Amélie G; Vermeulen, Nicolas; Mermillod, Martial

    2016-10-01

    This study explores whether the vagal connection between the heart and the brain is involved in prosocial behaviors. The Polyvagal Theory postulates that vagal activity underlies prosocial tendencies. Even if several results suggest that vagal activity is associated with prosocial behaviors, none of them used behavioral measures of prosociality to establish this relationship. We recorded the resting state vagal activity (reflected by High Frequency Heart Rate Variability, HF-HRV) of 48 (42 suitale for analysis) healthy human adults and measured their level of cooperation during a hawk-dove game. We also manipulated the consequence of mutual defection in the hawk-dove game (severe vs. moderate). Results show that HF-HRV is positively and linearly related to cooperation level, but only when the consequence of mutual defection is severe (compared to moderate). This supports that i) prosocial behaviors are likely to be underpinned by vagal functioning ii) physiological disposition to cooperate interacts with environmental context. We discuss these results within the theoretical framework of the Polyvagal Theory.

  17. Modulation of parasympathetic and baroreceptor control of heart rate.

    PubMed

    Ferrari, A U

    1993-03-01

    The heart rate is modulated from beat to beat by efferent vagal and sympathetic fibers, the former being the predominant mediators of the chronotropic influence of arterial baroreceptors and respiration and the latter being important in the cardiac responses to physical and mental stress. Cardiac vagal influences are modulated by a number of factors. These can be grouped as: 1) neural factors, such as the wakefulness-sleep cycle, the alerting reaction, and exercise; 2) humoral-pharmacological factors, such as angiotensin II, atrial natriuretic factor, cardiac glycosides; 3) normal aging; 4) a number of cardiovascular and other diseases, such as arterial hypertension, coronary artery disease, congestive heart failure and diabetes mellitus. The mechanisms underlying modulation of cardiac vagal control are not completely understood, the range of the possibilities including structural or functional alterations in baroreceptor afferents, in central and efferent vagal pathways and in cardiac responsiveness to neural stimuli. Irrespective of the mechanisms involved, the modulation of cardiac vagal control may have important implications for normal cardiovascular homeostasis, as well as for the pathophysiology, diagnosis and prognosis of various diseases.

  18. Exercise Training Improves Heart Rate Variability after Methamphetamine Dependency

    PubMed Central

    Dolezal, Brett A.; Chudzynski, Joy; Dickerson, Daniel; Mooney, Larissa; Rawson, Richard A.; Garfinkel, Alan; Cooper, Christopher B.

    2014-01-01

    Purpose Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent MD participants with age-matched, drug free controls (DF) and also investigated whether HRV can be improved with exercise training in the MD participants. Methods In 50 participants (MD=28; DF=22) resting heart rate (R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice weekly exercise training (ME=14) or equal attention without training (MC=14) over 8 weeks. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P≤0.05. Results Participant characteristics were matched between groups: age 33±6 years; body mass 82.7±12 kg, BMI 26.8±4.1 kg•min−2, mean±SD. Compared with DF, the MD group had significantly higher resting heart rate (P<0.05), LFnu, and LF/HF (P<0.001) as well as lower SDNN, RMSSD, pNN50 and HFnu (all P<0.001). At randomization, HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P<0.001) increased SDNN (+14.7±2.0 ms, +34%), RMSSD (+19.6±4.2 ms, +63%), pNN50 (+22.6±2.7%, +173%), HFnu (+14.2±1.9, +60%) and decreased HR (−5.2±1.1 beats·min−1, −7%), LFnu (−9.6±1.5, −16%) and LF/HF (−0.7±0.3, −19%). These measures did not change from baseline in the MC group. Conclusion HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine dependent individuals. Moreover, physical training yielded a marked increase of HRV representing increased vagal modulation or improved autonomic balance. PMID:24162556

  19. Validation of Biofeedback Wearables for Photoplethysmographic Heart Rate Tracking

    PubMed Central

    Jo, Edward; Lewis, Kiana; Directo, Dean; Kim, Michael J.; Dolezal, Brett A.

    2016-01-01

    The purpose of this study was to examine the validity of HR measurements by two commercial-use activity trackers in comparison to ECG. Twenty-four healthy participants underwent the same 77-minute protocol during a single visit. Each participant completed an initial rest period of 15 minutes followed by 5 minute periods of each of the following activities: 60W and 120W cycling, walking, jogging, running, resisted arm raises, resisted lunges, and isometric plank. In between each exercise task was a 5-minute rest period. Each subject wore a Basis Peak (BPk) on one wrist and a Fitbit Charge HR (FB) on the opposite wrist. Criterion measurement of HR was administered by 12-lead ECG. Time synced data from each device and ECG were concurrently and electronically acquired throughout the entire 77-minute protocol. When examining data in aggregate, there was a strong correlation between BPk and ECG for HR (r = 0.92, p < 0.001) with a mean bias of -2.5 bpm (95% LoA 19.3, -24.4). The FB demonstrated a moderately strong correlation with ECG for HR (r = 0.83, p < 0.001) with an average mean bias of -8.8 bpm (95% LoA 24.2, -41.8). During physical efforts eliciting ECG HR > 116 bpm, the BPk demonstrated an r = 0.77 and mean bias = -4.9 bpm (95% LoA 21.3, -31.0) while the FB demonstrated an r = 0.58 and mean bias = -12.7 bpm (95% LoA 28.6, -54.0). The BPk satisfied validity criteria for HR monitors, however showed a marginal decline in accuracy with increasing physical effort (ECG HR > 116 bpm). The FB failed to satisfy validity criteria and demonstrated a substantial decrease in accuracy during higher exercise intensities. Key points Modern day wearable multi-sensor activity trackers incorporate reflective photoplethymography (PPG) for heart rate detection and monitoring at the dorsal wrist. This study examined the validity of two PPG-based activity trackers, the Basis Peak and Fitbit Charge HR. The Basis Peak performed with accuracy compared with ECG and results substantiate

  20. Sampling period determination for heart rate logging under an exercise regimen.

    PubMed

    McCarthy, M; Ringwood, J V

    2006-10-01

    Using a mathematical procedure, we determine appropriate sampling rates for logging heart rate, at a variety of exercise intensities. The mathematical procedure involves correlating exercise and heart rate data to determine a dynamical mathematical model, from which the frequency response of the relationship between exercise intensity and heart rate can be determined. The sampling rate is then straightforwardly deduced by making appropriate measurements on the frequency response curve. We show how careful consideration needs to be given to the choice of dynamical model structure and the work regimen, so that consistent and convincing conclusions can be drawn. We demonstrate that the dynamics of the work-rate/heart-rate system are dependent on the nominal work/heart rate, but a 5-s sampling period, as used in many commercial heart rate monitors, appears to be adequate, especially when some averaging is performed before logging.

  1. Determining the relationship of heart rate and blood pressure using voluntary cardio-respiratory synchronization (VCRS).

    PubMed

    Mason, Lynne I; Patterson, Robert P

    2003-11-01

    Voluntary cardio-respiratory synchronization (VCRS) was used to investigate heart rate and blood pressure changes in the supine position in 21 subjects. VCRS involves a breathing pattern that is synchronized with the cardiac cycle. The signals to inhale and exhale are derived from the ECG. In this study, the subjects inspired for four heart beats and expired for four heart beats for 35 cycles. This technique is designed to have the heart beat occur at exactly the same phase in the respiratory cycle and lends itself to the study of the influence of the respiration cycle on heart rate and blood pressure changes. The heart rate and blood pressure changed simultaneously in the same direction, with the largest significant positive change occurring on the second heart beat during inspiration. The authors discuss the potential of VCRS for research, and clinical applications as a respiration modulator for hypertension therapy or increased heart rate variability.

  2. Heart Rate and Initial Presentation of Cardiovascular Diseases (Caliber)

    ClinicalTrials.gov

    2013-09-17

    Abdominal Aortic Aneurysm; Coronary Heart Disease NOS; Unheralded Coronary Death; Intracerebral Haemorrhage; Heart Failure; Ischemic Stroke; Myocardial Infarction; Stroke; Peripheral Arterial Disease; Stable Angina Pectoris; Subarachnoid Haemorrhage; Transient Ischemic Attack; Unstable Angina; Cardiac Arrest, Sudden Cardiac Death

  3. Prognostic Value of the 24-Hour Neurological Examination in Anterior Circulation Ischemic Stroke: A post hoc Analysis of Two Randomized Controlled Stroke Trials

    PubMed Central

    Rangaraju, Srikant; Frankel, Michael; Jovin, Tudor G.

    2016-01-01

    Background Early prognostication of long-term outcomes following ischemic stroke can facilitate medical decision-making. We hypothesized that the 24-hour National Institute of Health Stroke Scale (NIHSS) predicts 3-month clinical outcomes in anterior circulation stroke. Methods Secondary analyses of the Interventional Management of Stroke 3 (IMS3) and intravenous tissue plasminogen activator (IV tPA) for acute ischemic stroke [National Institute of Neurological Diseases and Stroke (NINDS) IV tPA] trials were performed. In participants with documented 24-hour NIHSS and 3-month Modified Rankin Scale (mRS), the predictive power of the 24-hour NIHSS and 24-hour NIHSS improvement for 3-month outcomes [mRS 0-2 and Barthel Index (BI) ≥95] was assessed. Percentages of good outcome (mRS 0-2 or BI ≥95) at 3, 6, and 12 months and mean quality of life (EQ5D™) index at 3 months across 24-hour NIHSS quartiles were compared. Results The majority of the study participants were included (IMS3 n = 587/656, NINDS IV tPA n = 619/624). The 24-hour NIHSS was correlated with 3-month mRS (R = 0.73) with excellent predictive power for mRS 0-2 [area under the curve (AUC) = 0.91] and BI ≥95 (AUC = 0.9) in both cohorts. A model with the 24-hour NIHSS alone correctly classified 82-84% of patients in both cohorts. The percentages of good outcomes at 3-12 months across 24-hour NIHSS quartiles were similar in both cohorts. mRS 0-2 was achieved by 75.6-77.7% of patients with 24-hour NIHSS ≤11 but by only 1.4-3.6% with 24-hour NIHSS ≥20. The EQ5D index at 3 months varied among NIHSS 0-4 (mean 0.86 ± 0.16), 5-11 (0.77 ± 0.18), and 12-19 (0.59 ± 0.26) quartiles. Conclusions The 24-hour NIHSS strongly predicts long-term stroke outcomes and is associated with quality of life. Its easy availability, reliability, and validity support its use as an early prognostic marker and surrogate of clinical outcome in ischemic stroke. PMID:27051408

  4. Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission.

    PubMed

    Liu, Zhizhen; Wan, Yufeng; Zhang, Lin; Tian, Yu; Lv, Ke; Li, Yinghui; Wang, Chunhui; Chen, Xiaoping; Chen, Shanguang; Guo, Jinhu

    2015-01-01

    Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms.

  5. Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission.

    PubMed

    Liu, Zhizhen; Wan, Yufeng; Zhang, Lin; Tian, Yu; Lv, Ke; Li, Yinghui; Wang, Chunhui; Chen, Xiaoping; Chen, Shanguang; Guo, Jinhu

    2015-01-01

    Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms. PMID:26177621

  6. Design of an FECG scalp electrode fetal heart rate monitor.

    PubMed

    Reguig, F B; Kirk, D L

    1996-03-01

    The design of a fetal heart rate (FHR) monitor using fetal electrocardiogram (FECG) scalp electrodes is described. It is shown that the design approach followed two stages: generation of FHR pulses at R-R intervals and FHR computation. The former uses a simple hardware approach for QRS detection and R-wave enhancement, while the latter requires a software implementation in order to produce FHR traces on a beat to beat basis. The QRS detection is based on bandpass filtering using switched mode capacitor technique; the R-wave enhancement and amplitude information are achieved by differentiation followed by fullwave rectification and peak detection. An adaptive threshold together with a comparator circuit are used to generate FHR pulses at R-R intervals. Beat to beat variations of FHR traces are produced by hardware and software implementation on a Z80 microprocessor board. Results obtained by the FHR monitor are evaluated and contrasted to other commercial FHR monitors. PMID:8673321

  7. Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots

    SciTech Connect

    Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

    2010-10-25

    Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced 'modified' Sensitivity (SE deg.) and 'modified' Positive Predictive Value (PPV deg.) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

  8. Nonlinear modelling and control for heart rate response to exercise.

    PubMed

    Zhang, Y; Chen, W; Su, S W; Celler, B

    2012-01-01

    In order to accurately regulate cardiovascular response to exercise for individual exerciser, this study proposes a modelling and control integrated approach based on ε-insensitive Support Vector Regression (SVR) and switching control strategy. Firstly, a control oriented modelling approach is proposed to depict nonlinear behaviours of cardiovascular response at both onset and offset of treadmill exercises by using support vector machine regression. Then, based on the established nonlinear time-variant model, a novel switching Model Predictive Control (MPC) algorithm has been proposed for the optimisation of exercise efforts. The designed controller can take into account both coefficient drifting and parameter jump by embedding the identified model coefficient into the optimiser and adopting switching strategy during the transfer between onset and offset of exercises. The effectiveness of the proposed modelling and control approach was shown from the regulation of dynamical heart rate response to exercise through simulation using MATLAB.

  9. Plasma bevantolol concentration and heart rate in rabbits.

    PubMed

    Liu, X Q; Ye, X L; Zhu, H Q; Huang, S K

    1993-05-01

    Bevantolol (Bev, 5, 10 mg.kg-1) was injected i.v. to rabbits. A measure the lag time of heart rate (HR) response behind the changes in plasma Bev concentration (K(eo)), and the sensitivity of the site of action of Bev (EC50) were determined. The K(eo) were 0.03 +/- 0.02 and 0.029 +/- 0.009 min-1 and the EC50 were 0.2 +/- 0.1 and 0.27 +/- 0.14 microgram.ml-1 respectively for the 2 dosages. The peak changes in HR lagged behind the changes in plasma Bev concentration. There were no significant changes in both pharmacokinetic and pharmacodynamic parameters between the dosages.

  10. Heart rate, startle response, and intrusive trauma memories

    PubMed Central

    Chou, Chia-Ying; Marca, Roberto La; Steptoe, Andrew; Brewin, Chris R

    2014-01-01

    The current study adopted the trauma film paradigm to examine potential moderators affecting heart rate (HR) as an indicator of peritraumatic psychological states and as a predictor of intrusive memories. We replicated previous findings that perifilm HR decreases predicted the development of intrusive images and further showed this effect to be specific to images rather than thoughts, and to detail rather than gist recognition memory. Moreover, a group of individuals showing both an atypical sudden reduction in HR after a startle stimulus and higher trait dissociation was identified. Only among these individuals was lower perifilm HR found to indicate higher state dissociation, fear, and anxiety, along with reduced vividness of intrusions. The current findings emphasize how peritraumatic physiological responses relate to emotional reactions and intrusive memory. The moderating role of individual difference in stress defense style was highlighted. PMID:24397333

  11. Alcohol-dependence syndrome: Postural challenge on heart rate variability

    PubMed Central

    Sucharita, S.; Pradeep, Johnson; Vincent, Anoop; Vaz, M.; Srinivasan, K.

    2012-01-01

    Background: Cardiac autonomic involvement in Alcohol-Dependence Syndrome (ADS) patients has been demonstrated using conventional autonomic tests. Resting heart rate variability (HRV) without normalization has also been reported. Aims: To evaluate cardiac autonomic changes with postural challenge using HRV in ADS and controls while controlling for confounding factors. Settings and Design: Cross-sectional study involving 27 male subjects with ADS and age-matched healthy controls. Materials and Methods: Clinical assessments included Schedules for Clinical Assessment in Neuropsychiatry and Severity of Alcohol Dependence Questionnaire. Spectral measures of HRV while lying and with active standing were assessed. Results: There was an attenuated response in delta high-frequency (P=0.06) and delta low-frequency (P=0.04) power to standing in ADS subjects compared with controls. Conclusion: Patients with ADS appear to have attenuated cardiac vagal and sympathetic responses to standing. HRV with postural challenge may help earlier recognition of autonomic dysfunction in ADS. PMID:23226850

  12. Heart Rate Variability Dynamics for the Prognosis of Cardiovascular Risk

    PubMed Central

    Ramirez-Villegas, Juan F.; Lam-Espinosa, Eric; Ramirez-Moreno, David F.; Calvo-Echeverry, Paulo C.; Agredo-Rodriguez, Wilfredo

    2011-01-01

    Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis. PMID:21386966

  13. Emergence of dynamical complexity related to human heart rate variability

    NASA Astrophysics Data System (ADS)

    Chang, Mei-Chu; Peng, C.-K.; Stanley, H. Eugene

    2014-12-01

    We apply the refined composite multiscale entropy (MSE) method to a one-dimensional directed small-world network composed of nodes whose states are binary and whose dynamics obey the majority rule. We find that the resulting fluctuating signal becomes dynamically complex. This dynamical complexity is caused (i) by the presence of both short-range connections and long-range shortcuts and (ii) by how well the system can adapt to the noisy environment. By tuning the adaptability of the environment and the long-range shortcuts we can increase or decrease the dynamical complexity, thereby modeling trends found in the MSE of a healthy human heart rate in different physiological states. When the shortcut and adaptability values increase, the complexity in the system dynamics becomes uncorrelated.

  14. Chronomics of heart rate variability on earth and in space.

    PubMed

    Otsuka, K; Izumi, R; Ishioka, N; Ohshima, H; Mukai, C

    2009-10-01

    Chronomes are time structures consisting of multifrequency rhythms, elements of chaos, and trends in chaotic and rhythmic endpoints. Chronomics maps the dynamics of organisms' broad interactions with the environment near and far, rather than merely the daily routines. We introduced the chronomics of heart rate variability (HRV), characterized by a broad time structure, that includes the prominent circadians and also ultradian (notably about 8h and about 12h) and infradian (notably about-weekly, about-yearly, and about 10-yearly) changes, in addition to undergoing trends with aging. Alterations in these HRV chronomes are known to predict the presence of disease in the near future. Thus, for the health and safety of astronauts, HRV chronomes should be assessed before, during and after the mission in the International Space Station to check for any alteration. Future work should focus on how phenomena in the cosmos, including helio- and geomagnetics, can affect physiological chronomes, those of the HRV in particular.

  15. Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots

    NASA Astrophysics Data System (ADS)

    Georgieva, A. E.; Payne, S. J.; Moulden, M.; Redman, C. W. G.

    2010-10-01

    Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced `modified' Sensitivity (SE°) and `modified' Positive Predictive Value (PPV°) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

  16. Phasic heart rate changes during word translation of different difficulties.

    PubMed

    Pfurtscheller, Gert; Grabner, Roland H; Brunner, Clemens; Neuper, Christa

    2007-09-01

    The heart rate (HR) can be modulated by diverse mental activities ranging from stimulus anticipation to higher order cognitive information processing. In the present study we report on HR changes during word translation and examine how the HR is influenced by the difficulty of the translation task. Twelve students of translation and interpreting were presented English high- and low-frequency words as well as familiar and unfamiliar technical terms that had to be translated into German. Analyses revealed that words of higher translation difficulty were accompanied by a more pronounced HR deceleration than words that were easier to translate. We additionally show that anticipatory HR deceleration and HR changes induced by motor preparation and activity due to typing the translation do not depend on task difficulty. These results provide first evidence of a link between task difficulty in language translation and event-related HR changes. PMID:17608800

  17. Correlated and uncorrelated heart rate fluctuations during relaxing visualization

    NASA Astrophysics Data System (ADS)

    Papasimakis, N.; Pallikari, F.

    2010-05-01

    The heart rate variability (HRV) of healthy subjects practicing relaxing visualization is studied by use of three multiscale analysis techniques: the detrended fluctuation analysis (DFA), the entropy in natural time (ENT) and the average wavelet (AWC) coefficient. The scaling exponent of normal interbeat interval increments exhibits characteristics of the presence of long-range correlations. During relaxing visualization the HRV dynamics change in the sense that two new features emerge independent of each other: a respiration-induced periodicity that often dominates the HRV at short scales (<40 interbeat intervals) and the decrease of the scaling exponent at longer scales (40-512 interbeat intervals). In certain cases, the scaling exponent during relaxing visualization indicates the breakdown of long-range correlations. These characteristics have been previously seen in the HRV dynamics during non-REM sleep.

  18. The Effect of Exertion on Heart Rate and Rating of Perceived Exertion in Acutely Concussed Individuals

    PubMed Central

    Hinds, Andrea; Leddy, John; Freitas, Michael; Czuczman, Natalie; Willer, Barry

    2016-01-01

    Objective Research suggests that one physiological effect of concussion is a disruption in regulation of autonomic nervous system control that affects the balance between parasympathetic and sympathetic output. While changes in heart rate after concussion have been observed, the nature of the heart rate change during progressive exercise has not been well evaluated in acutely symptomatic patients. Additionally, little is known about the relationship between HR and RPE in this population. Methods We compared changes in heart rate and perceived effort during graded treadmill exertion in recently concussed patients to elucidate the effect of brain injury on cardiovascular response to exercise. Resting HR, HR on exercise initiation, and changes in HR and RPE during the Buffalo Concussion Treadmill Test (BCTT) were compared on two test visits: When patients were symptomatic (acute) and after recovery. Results were compared with the test-retest results obtained from a control group consisting of healthy, non-concussed individuals. Results Patients had a significantly lower HR at onset of exercise when acutely concussed as compared to when recovered and reported greater perceived exertion at every exercise intensity level when symptomatic, despite exercising at lower workloads, than when recovered. Sympathetic response to increased exertion was not affected by concussion - HR increased in response to exercise at a comparable rate in both tests. These differences observed in response to exercise between the first BCTT and follow-up evaluation in initially concussed patients were not present in non-concussed individuals. Conclusion Our results suggest that during the acute phase after concussion, acutely concussed patients demonstrated an impaired ability to shift from parasympathetic to sympathetic control over heart rate at the onset of exercise. Changes in the autonomic nervous system after concussion may be more complex than previously reported. Continued evaluation of

  19. Heart Rate Variability in Porcine Progressive Peritonitis-Induced Sepsis

    PubMed Central

    Jarkovska, Dagmar; Valesova, Lenka; Chvojka, Jiri; Benes, Jan; Sviglerova, Jitka; Florova, Blanka; Nalos, Lukas; Matejovic, Martin; Stengl, Milan

    2016-01-01

    Accumulating evidence suggests that heart rate variability (HRV) alterations could serve as an indicator of sepsis progression and outcome, however, the relationships of HRV and major pathophysiological processes of sepsis remain unclear. Therefore, in this experimental study HRV was investigated in a clinically relevant long-term porcine model of severe sepsis/septic shock. HRV was analyzed by several methods and the parameters were correlated with pathophysiological processes of sepsis. In 16 anesthetized, mechanically ventilated, and instrumented domestic pigs of either gender, sepsis was induced by fecal peritonitis. Experimental subjects were screened up to the refractory shock development or death. ECG was continuously recorded throughout the experiment, afterwards RR intervals were detected and HRV parameters computed automatically using custom made measurement and analysis MATLAB routines. In all septic animals, progressive hyperdynamic septic shock developed. The statistical measures of HRV, geometrical measures of HRV and Poincaré plot analysis revealed a pronounced reduction of HRV that developed quickly upon the onset of sepsis and was maintained throughout the experiment. The frequency domain analysis demonstrated a decrease in the high frequency component and increase in the low frequency component together with an increase of the low/high frequency component ratio. The reduction of HRV parameters preceded sepsis-associated hemodynamic changes including heart rate increase or shock progression. In a clinically relevant porcine model of peritonitis-induced progressive septic shock, reduction of HRV parameters heralded sepsis development. HRV reduction was associated with a pronounced parasympathetic inhibition and a shift of sympathovagal balance. Early reduction of HRV may serve as a non-invasive and sensitive marker of systemic inflammatory syndrome, thereby widening the therapeutic window for early interventions. PMID:26779039

  20. Heart Rate Variability and Arrhythmic Burden in Pulmonary Hypertension.

    PubMed

    Witte, C; Meyer Zur Heide Genannt Meyer-Arend, J U; Andrié, R; Schrickel, J W; Hammerstingl, C; Schwab, J O; Nickenig, G; Skowasch, D; Pizarro, C

    2016-01-01

    A growing body of evidence indicates that sudden cardiac death constitutes a major cause of mortality in pulmonary hypertension (PH). As validated method to evaluate cardiac autonomic system dysfunction, alterations in heart rate variability (HRV) are predictive of arrhythmic events, particularly in left ventricular disease. Here, we sought to determine the clinical value of HRV assessment in PH. Sixty-four patients were allocated to different PH-subgroups in this prospectively conducted trial: 25 patients with pulmonary arterial hypertension (PAH), 11 patients with chronic thromboembolic PH (CTEPH), and 28 patients with COPD-induced PH. All patients underwent 24-h Holter electrocardiogram for HRV assessment by time- and frequency-domain analysis. Arrhythmic burden was evaluated by manual analysis and complementary automatic measurement of premature atrial and ventricular contractions. The results were compared to 31 healthy controls. The PAH patients offered a significantly higher mean heart rate (78.6 ± 10.4 bpm vs. 70.1 ± 10.3 bpm, p = 0.04), a higher burden of premature ventricular contractions (p < 0.01), and decreases in HRV (SDNN: p < 0.01; SDANN: p < 0.01; very low frequency: p < 0.01; low frequency/high frequency ratio: p < 0.01; total power: p = 0.02). In CTEPH patients, only the amount of premature ventricular contractions differed from controls (p < 0.01), whereas in COPD both premature atrial contraction count and frequency-domain-based HRV manifested significant differences. In conclusion, PAH appears to be primarily affected by HRV alterations and ventricular arrhythmic burden, indicating a high risk for malignant arrhythmic events. PMID:27241509

  1. Relationship between Arousal Intensity and Heart Rate Response to Arousal

    PubMed Central

    Azarbarzin, Ali; Ostrowski, Michele; Hanly, Patrick; Younes, Magdy

    2014-01-01

    Study Objectives: The visual appearance of cortical arousals varies considerably, from barely meeting scoring criteria to very intense arousals. Arousal from sleep is associated with an increase in heart rate (HR). Our objective was to quantify the intensity of arousals in an objective manner using the time and frequency characteristics of the electroencephalogram (EEG) and to determine whether HR response to arousal correlates with arousal intensity so determined. Design: Post hoc analysis of 20 preexisting polysomnography (PSG) files. Setting: Research and Development Laboratory (YRT Limited). Participants: N/A. Interventions: None. Measurements and Results: Arousals were scored using the American Academy of Sleep Medicine criteria. The EEG signals' time and frequency characteristics were determined using wavelet analysis. An automatic algorithm was developed to scale arousal intensity based on the change in wavelet features and data from a training set obtained from 271 arousals visually scaled between zero and nine (most intense). There were 2,695 arousals in 20 PSGs that were scaled. HR response (ΔHR) was defined as the difference between the highest HR in the interval [arousal-onset to (arousal-end +8 sec)] and the highest HR between 2 and 12 sec preceding arousal onset. There was a strong correlation between arousal scale and ΔHR within each subject (average r: 0.95 ± 0.04). The slope of the relationship varied among subjects (0.7-2.4 min-1/unit scale). Conclusions: Arousal intensity, quantified by wavelet transform, is strongly associated with arousal-related tachycardia, and the gain of the relationship varies among subjects. Quantifying arousal intensity in PSGs provides additional information that may be clinically relevant. Citation: Azarbarzin A; Ostrowski M; Hanly P; Younes M. Relationship between arousal intensity and heart rate response to arousal. SLEEP 2014;37(4):645-653. PMID:24899756

  2. Running demands and heart rate response in rugby sevens referees.

    PubMed

    Suarez-Arrones, Luis; Calvo-Lluch, África; Portillo, Javier; Sánchez, Francisco; Mendez-Villanueva, Alberto

    2013-06-01

    The purpose of this study was to examine for the first time the match running demands and heart rate (HR) responses associated with elite rugby sevens referees. Twelve referees were analyzed over 38 games, using Global Positioning System. Referees covered an average distance of 1665.2 ± 203.5 m per game (15.1 ± 0.5 minutes). Over this distance, 22.3% (371.8 ± 48.9 m) was spent standing and walking, 25.9% (431.2 ± 92.6 m) jogging, 12.4% (206.5 ± 53.2 m) cruising, 23.8% (395.6 ± 94.3 m) striding, 8% (133.3 ± 61.6 m) high-intensity running, and 7.6% (126.7 ± 87.3 m) sprinting. The average maximal distance of sprints, the number of sprints, and the mean sprint distance over the game were 31.3 ± 13.4 m, 5.76 ± 3.6 sprints, and 19.9 ± 7.8 m, respectively. The referee's work-to-rest ratio was 3.5:1. There were no statistical differences between the first and second half in any of the running variables analyzed. The average HR in the second half (160 ± 9 b·min(-1); 86 ± 5% maximal heart rate (HRmax) of the estimated) was higher (p < 0.05) than the HR recorded in the first half (154 ± 11 b·min(-1); 83 ± 6% of the estimated HRmax). This study also suggests that the physical demands of referring in rugby sevens are quite different from those encountered in other rugby codes, and the training regimes need to meet the increased overall running demands and high-intensity running activity.

  3. Heart Rate and Motion Analysis by GPS in Beach Soccer

    PubMed Central

    Castellano, Julen; Casamichana, David

    2010-01-01

    Although beach soccer has become increasingly popular in recent years very little scientific research has been conducted into the sport. A pilot study was carried out with the aim of examining the physiological (heart rate) and physical (motion analysis) responses of beach soccer players during competitive matches. Ten players (age 25.5 ± 0.5 years; height 1.80 ± 0.08 m; weight 78.2 ± 5.6 kg.) were studied over five beach soccer matches. The physiological demands were analysed by measuring heart rate (HR) using telemetric devices, while the physical profile was evaluated by recording motion and speed by means of GPS devices. During competitive matches, players obtained a HRmean of 165.2 bpm (86.5% HRmax), with 59.3% of the time participating (TP) corresponding to values above 90% of the HRmax. The distance covered per minute of participation was 97.7 m, with 9.5% of this distance corresponding to high-intensity running and 2.5% to sprint; the work:rest ratio was 1.4:1 and the maximum speed 21.7 km·h-1. These results showed that beach soccer is an intermittent physical activity of greater intensity than other team games. It requires a major contribution from the anaerobic system as emphasis is placed on players making quick bursts of high-intensity activity separated by brief rest periods. Key points The distance covered per minute of play is around 100 m. Beach soccer is an intermittent sport with a work:rest ratio of 1.4:1. The playing surface in beach soccer is an important handicap to obtain maximum speeds. Beach soccer has a high physiological intensity, with more than half of the game is spent at intensities above 90 % of the HRmax. PMID:24149392

  4. Early ventilation-heart rate breakpoint during incremental cycling exercise.

    PubMed

    Gravier, G; Delliaux, S; Ba, A; Delpierre, S; Guieu, R; Jammes, Y

    2014-03-01

    Previous observations having reported a transient hypoxia at the onset of incremental exercise, we investigated the existence of concomitant ventilatory and heart rate (HR) breakpoints.33 subjects executed a maximal cycling exercise with averaging for successive 5-s periods of HR, ventilation, tidal volume (VT), mean inspiratory flow rate (VT/Ti), and end-tidal partial pressures of O2 (PETO2) and CO2. In 10 subjects, the transcutaneous partial pressure of O2 (PtcO2) was recorded and the venous blood lactic acid (LA) concentration measured.At the beginning of exercise, PETO2 decreased, reaching a nadir, then progressively increased until the exercise ended. PtcO2 varied in parallel. Whether or not a 0-W cycling period preceded the incremental exercise, the rate of changes in VE, VT, VT/Ti and HR significantly increased when the nadir PO2 was reached. The ventilatory/ HR breakpoint was measured at 33±4% of VO2max, whereas the ventilatory threshold (VTh) was detected at 67±4% of VO2max and LA began to increase at 45 to 50% of VO2max.During incremental cycling exercise, we identified the existence of HR and ventilatory breakpoints in advance of both lactate and ventilatory thresholds which coincided with modest hypoxia and hypercapnia.

  5. Resonance of about-weekly human heart rate rhythm with solar activity change.

    PubMed

    Cornelissen, G; Halberg, F; Wendt, H W; Bingham, C; Sothern, R B; Haus, E; Kleitman, E; Kleitman, N; Revilla, M A; Revilla, M; Breus, T K; Pimenov, K; Grigoriev, A E; Mitish, M D; Yatsyk, G V; Syutkina, E V

    1996-12-01

    In several human adults, certain solar activity rhythms may influence an about 7-day rhythm in heart rate. When no about-weekly feature was found in the rate of change in sunspot area, a measure of solar activity, the double amplitude of a circadian heart rate rhythm, approximated by the fit of a 7-day cosine curve, was lower, as was heart rate corresponds to about-weekly features in solar activity and/or relates to a sunspot cycle.

  6. Comparison of heart rate variability and pulse rate variability detected with photoplethysmography

    NASA Astrophysics Data System (ADS)

    Rauh, Robert; Limley, Robert; Bauer, Rainer-Dieter; Radespiel-Troger, Martin; Mueck-Weymann, Michael

    2004-08-01

    This study compares ear photoplethysmography (PPG) and electrocardiogram (ECG) in providing accurate heart beat intervals for use in calculations of heart rate variability (HRV, from ECG) or of pulse rate variability (PRV, from PPG) respectively. Simultaneous measurements were taken from 44 healthy subjects at rest during spontaneous breathing and during forced metronomic breathing (6/min). Under both conditions, highly significant (p > 0.001) correlations (1.0 > r > 0.97) were found between all evaluated common HRV and PRV parameters. However, under both conditions the PRV parameters were higher than HRV. In addition, we calculated the limits of agreement according to Bland and Altman between both techniques and found good agreement (< 10% difference) for heart rate and standard deviation of normal-to-normal intervals (SDNN), but only moderate (10-20%) or even insufficient (> 20%) agreement for other standard HRV and PRV parameters. Thus, PRV data seem to be acceptable for screening purposes but, at least at this state of knowledge, not for medical decision making. However, further studies are needed before more certain determination can be made.

  7. Ambulatory and Challenge-Associated Heart Rate Variability Measures Predict Cardiac Responses to “Real-World” Acute Emotional Stress

    PubMed Central

    Dikecligil, GN; Mujica-Parodi, LR

    2010-01-01

    Background Heart rate variability (HRV) measures homeostatic regulation of the autonomic nervous system in response to perturbation, and has been previously shown to quantify risk for cardiac events. In spite of known interactions between stress vulnerability, psychiatric illness, and cardiac health, however, to our knowledge this is the first study to directly compare the value of laboratory HRV in predicting autonomic modulation of “real-world” emotional stress. Methods We recorded ECG on 56 subjects: first, within the laboratory, and then during an acute emotional stressor: a first-time skydive. Laboratory sessions included two five-minute ECG recordings separated by one ambulatory 24-hour recording. To test the efficacy of introducing a mild emotional challenge, during each of the five-minute laboratory recordings subjects viewed either aversive or benign images. Following the laboratory session, subjects participated in the acute stressor wearing a holter ECG. Artifact-free ECGs (N=33) were analyzed for HRV, then statistically compared across laboratory and acute stress sessions. Results There were robust correlations (r=0.7-0.8) between the laboratory and acute stress HRV, indicating that the two most useful paradigms (long-term wake, followed by short-term challenge) also were most sensitive to distinct components of the acute stressor: the former correlated with the fine-tuned regulatory modulation occurring immediately prior and following the acute stressor, while the latter correlated with gross amplitude and recovery. Conclusions Our results confirmed the efficacy of laboratory-acquired HRV in predicting autonomic response to acute emotional stress, and suggest that ambulatory and challenge protocols enhance predictive value. PMID:20299007

  8. Effect of physical activity on heart rate variability in normal weight, overweight and obese subjects: results from the SAPALDIA study

    PubMed Central

    Dietrich, Denise Felber; Ackermann-Liebrich, Ursula; Schindler, Christian; Barthélémy, Jean-Claude; Brändli, Otto; Gold, Diane R; Knöpfli, Bruno; Probst-Hensch, Nicole M; Roche, Frédéric; Tschopp, Jean-Marie; von Eckardstein, Arnold; Gaspoz, Jean-Michel

    2011-01-01

    Many studies have demonstrated an association of both a sedentary lifestyle and a high body mass index (BMI) with greater risk for cardiovascular disease. Within the prospective SAPALDIA cohort (Swiss cohort study on Air Pollution and Lung Diseases in Adults), we investigated whether regular exercise was protective against reduced heart rate variability (HRV), a clinically relevant predictor of cardiovascular morbidity and mortality, and whether adverse effects of obesity and weight gain on HRV were modified by regular exercise. 24-hour electrocardiograms were recorded in 1712 randomly selected SAPALDIA participants aged ≥50, for whom BMI was assessed in the years 1991 and 2001–2003. Other examinations included an interview investigating health status (especially respiratory and cardiovascular health and health relevant behaviours including physical activity) and measurements of blood pressure, body height and weight. The association between regular physical activity and HRV and interactions with BMI and BMI change was assessed in multivariable linear regression analyses. Compared to sedentary obese subjects, SDNN (standard deviation of all RR intervals) was 14% (95% CI: 8–20%) higher in sedentary normal weight subjects; 19% (CI: 12–27%) higher in normal weight subjects exercising regularly ≥ 2h/week; and 19% (CI:11–28%) higher in obese subjects exercising regularly ≥ 2h/week. Compared with sedentary subjects who gained weight, those who gained weight but did exercise regularly had a 13% higher SDNN (CI: 7–20%). Regular physical exercise has strong beneficial effects on cardiac autonomic nervous function and thus appears to offset the negative effect of obesity on HRV. PMID:18597107

  9. Behavioral correlates of heart rates of free-living Greater White-fronted Geese

    USGS Publications Warehouse

    Ely, C.R.; Ward, D.H.; Bollinger, K.S.

    1999-01-01

    We simultaneously monitored the heart rate and behavior of nine free-living Greater White-fronted Geese (Anser albifrons) on their wintering grounds in northern California. Heart rates of wild geese were monitored via abdominally-implanted radio transmitters with electrodes that received electrical impulses of the heart and emitted a radio signal with each ventricular contraction. Post-operative birds appeared to behave normally, readily rejoining flocks and flying up to 15 km daily from night-time roost sites to feed in surrounding agricultural fields. Heart rates varied significantly among individuals and among behaviors, and ranged from less than 100 beats per minute (BPM) during resting, to over 400 BPM during flight. Heart rates varied from 80 to 140 BPM during non-strenuous activities such as walking, feeding, and maintenance activities, to about 180 BPM when birds became alert, and over 400 BPM when birds were startled, even if they did not take flight. Postflight heart rate recovery time averaged < 10 sec. During agonistic encounters, heart rate exceeded 400 BPM; heart rates during social interactions were not predictable solely from postures, as heart rates were context-dependent, and were highest in initial encounters among individuals. Instantaneous measures of physiological parameters, such as heart rate, are often better indicators of the degree of response to external stimuli than visual observations and can be used to improve estimates of energy expenditure based solely on activity data.

  10. Helping from the heart: Voluntary upregulation of heart rate variability predicts altruistic behavior.

    PubMed

    Bornemann, Boris; Kok, Bethany E; Böckler, Anne; Singer, Tania

    2016-09-01

    Our various daily activities continually require regulation of our internal state. These regulatory processes covary with changes in High Frequency Heart Rate Variability (HF-HRV), a marker of parasympathetic activity. Specifically, incidental increases in HF-HRV accompany positive social engagement behavior and prosocial action. Little is known about deliberate regulation of HF-HRV and the role of voluntary parasympathetic regulation in prosocial behavior. Here, we present a novel biofeedback task that measures the ability to deliberately increase HF-HRV. In two large samples, we find that a) participants are able to voluntarily upregulate HF-HRV, and b) variation in this ability predicts individual differences in altruistic prosocial behavior, but not non-altruistic forms of prosociality, assessed through 14 different measures. Our findings suggest that self-induction of parasympathetic states is involved in altruistic action. The biofeedback task may provide a measure of deliberate parasympathetic regulation, with implications for the study of attention, emotion, and social behavior.

  11. Cortisol release, heart rate and heart rate variability in the horse and its rider: different responses to training and performance.

    PubMed

    von Lewinski, Mareike; Biau, Sophie; Erber, Regina; Ille, Natascha; Aurich, Jörg; Faure, Jean-Michel; Möstl, Erich; Aurich, Christine

    2013-08-01

    Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (P<0.001) but did not differ between performance and rehearsal. HR in horses and riders increased during the rehearsal and the public performance (P<0.001) but the increase in HR was more pronounced (P<0.01) in riders than in their horses during the public performance (from 91 ± 10 to 150 ± 15 beats/min) compared to the rehearsal (from 94 ± 10 to 118 ± 12 beats/min). The SDRR decreased significantly during the equestrian tasks in riders (P<0.001), but not in their horses. The RMSSD decreased in horses and riders (P<0.001) during rehearsal and performance, indicating a decrease in parasympathetic tone. The decrease in RMSSD in the riders was more pronounced (P<0.05) during the performance (from 32.6 ± 6.6 to 3.8 ± 0.3 ms) than during the rehearsal (from 27.5 ± 4.2 to 6.6 ± 0.6 ms). The study has shown that the presence of spectators caused more pronounced changes in cardiac activity in the riders than it did in their horses.

  12. Heart Rate Variability for Quantification of Autonomic Dysfunction in Fibromyalgia

    PubMed Central

    Kang, Jin Ho; Hong, Seok Hyun; Lee, Chang Hyun; Choi, Byoong Yong

    2016-01-01

    Objective To quantify autonomic dysfunction in fibromyalgia patients compared to healthy controls using heart rate variability (HRV). Methods Sixteen patients with fibromyalgia and 16 healthy controls were recruited in this case control study. HRV was measured using the time-domain method incorporating the following parameters: total heartbeats, the mean of intervals between consecutive heartbeats (R-R intervals), the standard deviation of normal to normal R-R intervals (SDNN), the square root of the mean squared differences of successive R-R intervals (RMSSD), ratio of SDNN to RMSSD (SDNN/RMSSD), and difference between the longest and shortest R-R interval under different three conditions including normal quiet breathing, rate controlled breathing, and Valsalva maneuver. The severity of autonomic symptoms in the group of patients with fibromyalgia was measured by Composite Autonomic Symptom Scale 31 (COMPASS 31). Then we analyzed the difference between the fibromyalgia and control groups and the correlation between the COMPASS 31 and aforementioned HRV parameters in the study groups. Results Patients with fibromyalgia had significantly higher SDNN/RMSSD values under both normal quiet breathing and rate controlled breathing compared to controls. Differences between the longest and shortest R-R interval under Valsalva maneuver were also significantly lower in patients with fibromyalgia than in controls. COMPASS 31 score was negatively correlated with SDNN/RMSSD values under rate controlled breathing. Conclusion SDNN/RMSSD is a valuable parameter for autonomic nervous system function and can be used to quantify subjective autonomic symptoms in patients with fibromyalgia. PMID:27152281

  13. A comparison between computer-controlled and set work rate exercise based on target heart rate

    NASA Technical Reports Server (NTRS)

    Pratt, Wanda M.; Siconolfi, Steven F.; Webster, Laurie; Hayes, Judith C.; Mazzocca, Augustus D.; Harris, Bernard A., Jr.

    1991-01-01

    Two methods are compared for observing the heart rate (HR), metabolic equivalents, and time in target HR zone (defined as the target HR + or - 5 bpm) during 20 min of exercise at a prescribed intensity of the maximum working capacity. In one method, called set-work rate exercise, the information from a graded exercise test is used to select a target HR and to calculate a corresponding constant work rate that should induce the desired HR. In the other method, the work rate is controlled by a computer algorithm to achieve and maintain a prescribed target HR. It is shown that computer-controlled exercise is an effective alternative to the traditional set work rate exercise, particularly when tight control of cardiovascular responses is necessary.

  14. Label-free mass spectrometry proteome quantification of human embryonic kidney cells following 24 hours of sialic acid overproduction

    PubMed Central

    2013-01-01

    Background Cell surface glycoprotein sialylation is one of the most ubiquitous glycan modifications found on higher eukaryotes. The surface sialylation pattern of cells is influenced by the cellular environment but also by the Golgi sialyltransferase activity and flux of metabolites through sialic acid producing pathways. Altered cell surface sialic acid patterns have been observed in several cancers and other pathological conditions. In this experiment we examined the cellular proteomic changes that occur in human embryonic kidney cells after 24 hours of sialic acid overproduction using N-Acetylmannosamine. We utilized high resolution mass spectrometry and label free protein quantification to characterize the relative changes in protein abundance as well as multiple reaction monitoring to quantify the cellular sialic acid levels. Results Using N-Acetylmannosamine we were able to induce sialic acid production to almost 70-fold compared to non-induced control cells. Mass spectrometric analysis of cellular proteome of control and induced cells identified 1802 proteins of which 105 displayed significant changes in abundance. Functional analysis of the resulting relative changes in protein abundance revealed regulation of several cellular pathways including protein transport, metabolic and signaling pathways and remodeling of epithelial adherens junctions. We also identified several physically interacting co-regulated proteins in the set of changed proteins. Conclusions In this experiment we show that increased metabolic flux through sialic acid producing pathway affects the abundance of several protein transport, epithelial adherens junction, signaling and metabolic pathway related proteins. PMID:23915316

  15. A comparison of regression and Bayesian change point analysis for extreme 24hours rainfall in South Australia

    NASA Astrophysics Data System (ADS)

    Kamruzzaman, M.; Beecham, S.; Metcalfe, A.

    2013-12-01

    We consider monthly extremes rainfall, aggregated over 24 hours, at 24 rainfall station in South Australia (SA). A self-organizing map (SOM) technique is used to draw contours of extreme for this area for each month. The possibility of change in extreme rainfall is investigated in two ways. The first is a multiple regression with time, month, station and their interaction as predictor variables. A confidence interval and for the linear and quadratic effects of time series are given. We have developed a strategy to possible improve prediction of extreme rainfall as a linear combination of original prediction. The dramatic improvement is a consequence of introducing squares and cross product of predictor variables is given in calibration, validation and re-calibration model. The similarity between fitted to the calibration and validation periods suggests that the hydrological process have been relatively stable over the period. The modeling strategy is empirical and will valid for different time period; although, in general, estimated coefficients could change substantially. The second analysis is a Bayesian change's point (BCP) analysis based on deseasonalised extreme data. A univariate BCP is applied in the data averaged over stations and compared with a multivariate BCP applied to the individual station records. The BCP is applied to investigate the possibility of sudden change rather than a smooth trend.

  16. Extracorporeal membrane oxygenation improves survival in a novel 24-hour pig model of severe acute respiratory distress syndrome.

    PubMed

    Araos, Joaquín; Alegría, Leyla; García, Patricio; Damiani, Felipe; Tapia, Pablo; Soto, Dagoberto; Salomon, Tatiana; Rodriguez, Felipe; Amthauer, Macarena; Erranz, Benjamín; Castro, Gabriel; Carreño, Pamela; Medina, Tania; Retamal, Jaime; Cruces, Pablo; Bugedo, Guillermo; Bruhn, Alejandro

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support. PMID:27398166

  17. Relative prognostic value of rest thallium-201 imaging, radionuclide ventriculography and 24 hour ambulatory electrocardiographic monitoring after acute myocardial infarction

    SciTech Connect

    Hakki, A.H.; Nestico, P.F.; Heo, J.; Unwala, A.A.; Iskandrian, A.S.

    1987-07-01

    Rest thallium-201 scintigraphy, radionuclide ventriculography and 24 hour Holter monitoring are acceptable methods to assess myocardial necrosis, performance and electrical instability. This study examined the relative value of the three tests, when obtained a mean of 7 days after acute myocardial infarction, in predicting 1 year mortality in 93 patients. Planar thallium-201 images were obtained in three projections and were scored on a scale of 0 to 4 in 15 segments (normal score = 60). Patients were classified as having high risk test results as follows: thallium score less than or equal to 45 (33 patients), left ventricular ejection fraction less than or equal to 40% (51 patients) and complex ventricular arrhythmias on Holter monitoring (36 patients). During the follow-up of 6.4 +/- 3.4 months (mean +/- SD), 15 patients died of cardiac causes. All three tests were important predictors of survival by univariate Cox survival analysis; the thallium score, however, was the only important predictor by multivariate analysis. The predictive power of the thallium score was comparable with that of combined ejection fraction and Holter monitoring (chi-square = 21 versus chi-square = 22). Thus, rest thallium-201 imaging performed before hospital discharge provides important prognostic information in survivors of acute myocardial infarction which is comparable with that provided by left ventricular ejection fraction and Holter monitoring. Patients with a lower thallium score (large perfusion defects) are at high risk of cardiac death during the first year after infarction.

  18. Hourly thermal load prediction for the next 24 hours by ARIMA, EWMA, LR and an artificial neural network

    SciTech Connect

    Kawashima, Minoru; Dorgan, C.E.; Mitchell, J.W.

    1995-08-01

    Predicting the thermal load for the next 24 hours is essential for optimal control of heating, ventilating, and air conditioning (HVAC) systems that use thermal cool storage. It can be useful in minimizing costs and energy in nonstorage systems. A cooperative research project between a US. university and a Japanese corporation investigated four generally used prediction methods to examine the basic models with variations and to compare the accuracy of each model. A cooling and heating seasonal data set with known next-day weather was used to evaluate the accuracy of each prediction method. The results indicate that an artificial neural network (ANN) model produces the most accurate thermal load predictions. After the initial comparisons with a computer-generated data set, the ANN model was applied to two measured building loads from another research project. These sets included typical measurement noise related to continuous field monitoring. The predictions of the next-day cooling load using the ANN prediction model were close to the actual data, even when the next-day weather was forecast. This confirms that the ANN model has sufficient accuracy and is the correct method for practical utilization in HVAC system control, thermal storage optimal control, and load/demand management.

  19. Dietary quality varies according to data collection instrument: a comparison between a food frequency questionnaire and 24-hour recall.

    PubMed

    Rodrigues, Paulo Rogério Melo; de Souza, Rita Adriana Gomes; De Cnop, Mara Lima; Monteiro, Luana Silva; Coura, Camila Pinheiro; Brito, Alessandra Page; Pereira, Rosangela Alves

    2016-02-01

    The objective of this study was to assess the agreement between the Brazilian Healthy Eating Index - Revised (BHEI-R), estimated by a food frequency questionnaire (FFQ) and multiple 24-hour recalls (24h-R). The Wilcoxon paired test, partial correlations (PC), intraclass correlation coefficient (ICC), and Bland-Altman method were used. The total BHEI-R scores and its components ("total fruits", "whole fruits", "total vegetables", "integral cereals", "saturated fat", "sodium", and "energy intake derived from solid fat, added sugar, and alcoholic beverages") were statistically different, with the ICC and PC indicating poor concordance and correlation. The mean concordance estimated for the total BHEI-R and its components varied from 68% for "integral cereals" to 147% for "whole fruits". The suitable concordance limits were violated for most of the components of the BHEI-R. Poor concordance was observed between the BHEI-R estimated by the FFQ and by multiple 24h-R, which indicated a strong reliability of the BHEI-R on the instrument used to collect information on food consumption. PMID:26910251

  20. Extracorporeal membrane oxygenation improves survival in a novel 24-hour pig model of severe acute respiratory distress syndrome

    PubMed Central

    Araos, Joaquín; Alegría, Leyla; García, Patricio; Damiani, Felipe; Tapia, Pablo; Soto, Dagoberto; Salomon, Tatiana; Rodriguez, Felipe; Amthauer, Macarena; Erranz, Benjamín; Castro, Gabriel; Carreño, Pamela; Medina, Tania; Retamal, Jaime; Cruces, Pablo; Bugedo, Guillermo; Bruhn, Alejandro

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support. PMID:27398166

  1. Extracorporeal membrane oxygenation improves survival in a novel 24-hour pig model of severe acute respiratory distress syndrome.

    PubMed

    Araos, Joaquín; Alegría, Leyla; García, Patricio; Damiani, Felipe; Tapia, Pablo; Soto, Dagoberto; Salomon, Tatiana; Rodriguez, Felipe; Amthauer, Macarena; Erranz, Benjamín; Castro, Gabriel; Carreño, Pamela; Medina, Tania; Retamal, Jaime; Cruces, Pablo; Bugedo, Guillermo; Bruhn, Alejandro

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support.

  2. Comparative studies on 24-hour urinary excretion in Japanese and Chinese adults and children--need for nutritional education.

    PubMed

    Mori, Mari; Xu, Jin-Wen; Mori, Hideki; Ling, Cheng Feng; Wei, Guo Hong; Yamori, Yukio

    2009-01-01

    In order to evaluate the effect of nutritional education on the risk of developing lifestyle-related diseases, we measured taurine and isoflavone content in 24-hour urine samples (24-U) of 3rd grade Chinese children (CC) and of age-matched Japanese children (JC), as well as adult Chinese and Japanese (CA, JA) according to the WHO-CARDIAC (Cardiovascular Diseases and Alimentary Comparison) Study protocol. There was a significantly higher prevalence of obesity and "thin" individuals in CC compared with JC. While K intake was not significantly different in the children, the sodium to potassium ratio (Na/ K) and the intake of sodium chloride (NaCl) were significantly higher in CC than in JC. Taurine excretion (24-U) was significantly higher in CC than in JC, but isoflavone excretion was significantly lower in CC than in JC. Taurine excretion was significantly lower in CA than in JA, while isoflavone excretion was almost the same in CA and JA. After nutritional education CC consumed more isoflavones than the control group that had been subjected to only environmental education. JC exhibited significantly higher 24-U taurine and isoflavone excretion after taking the nutritional class.

  3. Rhythmic variation in heart rate and respiration rate during space flight - Apollo 15

    NASA Technical Reports Server (NTRS)

    Rummel, J. A.

    1974-01-01

    As part of the operational biomedical monitoring for Apollo manned missions, ECG and respiration rate are telemetered at selected intervals to mission control. The data were collected as part of this monitoring program. These data were evaluated for circadian and ultradian rhythmicity because of their uniqueness. The ability to detect and quantitate biorhythms in living systems during space flight is an important aspect of evaluating hypotheses concerning the underlying mechanisms of these phenomena. Circadian variation in heart rate during space flight is demonstrated here. In analyzing generated time series data it has been found that period discrimination is much better than the theoretical limit.

  4. The autonomic nervous control of heart rate in ducks during voluntary diving.

    PubMed

    McPhail, L T; Jones, D R

    1999-01-01

    Autonomic nervous control of heart rate was studied in voluntarily diving ducks (Aythya affinis). Ducks were injected with the muscarinic blocker atropine, the beta-adrenergic blocker nadolol, the beta-adrenergic agonist isoproterenol, and a combination of both atropine and nadolol. Saline injection was used as a control treatment. The reduction in heart rate (from the predive level) normally seen during a dive was abolished by atropine. Nadolol reduced heart rate during all phases of diving activity-predive, dive, and postdive-indicating that sympathetic output to the heart was not withdrawn during diving. Isoproterenol increased heart rate before, during, and after the dive, although the proportional increase in heart rate was not as high during the dive as compared with the increase in routine heart rate or heart rate during the predive or postdive phase. The parasympathetic system predominates in the control of heart rate during diving despite the maintenance of efferent sympathetic influences to the heart