The effects of gum chewing while walking on physical and physiological functions

PubMed Central

Hamada, Yuka; Yanaoka, Takuma; Kashiwabara, Kyoko; Kurata, Kuran; Yamamoto, Ryo; Kanno, Susumu; Ando, Tomonori; Miyashita, Masashi

2018-01-01

[Purpose] This study examined the effects of gum chewing while walking on physical and physiological functions. [Subjects and Methods] This study enrolled 46 male and female participants aged 21–69 years. In the experimental trial, participants walked at natural paces for 15 minutes while chewing two gum pellets after a 1-hour rest period. In the control trial, participants walked at natural paces for 15 minutes after ingesting powder containing the same ingredient, except the gum base, as the chewing gum. Heart rates, walking distances, walking speeds, steps, and energy expenditure were measured. [Results] Heart rates during walking and heart rate changes (i.e., from at rest to during walking) significantly increased during the gum trial compared with the control trial. Walking distance, walking speed, walking heart rate, and heart rate changes in male participants and walking heart rate and heart rate changes in female participants were significantly higher during the gum trial than the control trial. In middle-aged and elderly male participants aged ≥40 years, walking distance, walking speed, steps, and energy expenditure significantly increased during the gum trial than the control trial. [Conclusion] Gum chewing while walking measurably affects physical and physiological functions. PMID:29706720

Effect of Heart Rate on Arterial Stiffness as Assessed by Pulse Wave Velocity.

PubMed

Tan, Isabella; Butlin, Mark; Spronck, Bart; Xiao, Huanguang; Avolio, Alberto

2017-07-24

Vascular assessment is becoming increasingly important in the diagnosis of cardiovascular diseases. In particular, clinical assessment of arterial stiffness, as measured by pulse wave velocity (PWV), is gaining increased interest due to the recognition of PWV as an influential factor on the prognosis of hypertension as well as being an independent predictor of cardiovascular and all-cause mortality. Whilst age and blood pressure are established as the two major determinants of PWV, the influence of heart rate on PWV measurements remains controversial with conflicting results being observed in both acute and epidemiological studies. In a majority of studies investigating the acute effects of heart rate on PWV, results were confounded by concomitant changes in blood pressure. Observations from epidemiological studies have also failed to converge, with approximately just half of such studies reporting a significant blood-pressure-independent association between heart rate and PWV. Further to the lack of consensus on the effects of heart rate on PWV, the possible mechanisms contributing to observed PWV changes with heart rate have yet to be fully elucidated, although many investigators have attributed heart-rate related changes in arterial stiffness to the viscoelasticity of the arterial wall. With elevated heart rate being an independent prognostic factor of cardiovascular disease and its association with hypertension, the interaction between heart rate and PWV continues to be relevant in assessing cardiovascular risk. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Assessment of heart rate variability based on mobile device for planning physical activity

NASA Astrophysics Data System (ADS)

Svirin, I. S.; Epishina, E. V.; Voronin, V. V.; Semenishchev, E. A.; Solodova, E. N.; Nabilskaya, N. V.

2015-05-01

In this paper we present a method for the functional analysis of human heart based on electrocardiography (ECG) signals. The approach using the apparatus of analytical and differential geometry and correlation and regression analysis. ECG contains information on the current condition of the cardiovascular system as well as on the pathological changes in the heart. Mathematical processing of the heart rate variability allows to obtain a great set of mathematical and statistical characteristics. These characteristics of the heart rate are used when solving research problems to study physiological changes that determine functional changes of an individual. The proposed method implemented for up-to-date mobile Android and iOS based devices.

Developmental Change in Feedback Processing as Reflected by Phasic Heart Rate Changes

ERIC Educational Resources Information Center

Crone, Eveline A.; Jennings, J. Richard; Van der Molen, Maurits W.

2004-01-01

Heart rate was recorded from 3 age groups (8-10, 12, and 20-26 years) while they performed a probabilistic learning task. Stimuli had to be sorted by pressing a left versus right key, followed by positive or negative feedback. Adult heart rate slowed following negative feedback when stimuli were consistently mapped onto the left or right key…

Perinatal sulfur dioxide exposure alters brainstem parasympathetic control of heart rate.

PubMed

Woerman, Amanda L; Mendelowitz, David

2013-07-01

Sulfur dioxide (SO₂) is an air pollutant that impedes neonatal development and induces adverse cardiorespiratory health effects, including tachycardia. Here, an animal model was developed that enabled characterization of (i) in vivo alterations in heart rate and (ii) altered activity in brainstem neurons that control heart rate after perinatal SO₂ exposure. Pregnant Sprague-Dawley dams and their pups were exposed to 5 parts per million SO₂ for 1 h daily throughout gestation and 6 days postnatal. Electrocardiograms were recorded from pups at 5 days postnatal to examine changes in basal and diving reflex-evoked changes in heart rate following perinatal SO₂ exposure. In vitro studies employed whole-cell patch-clamp electrophysiology to examine changes in neurotransmission to cardiac vagal neurons within the nucleus ambiguus upon SO₂ exposure using a preparation that maintains fictive inspiratory activity recorded from the hypoglossal rootlet. Perinatal SO₂ exposure increased heart rate and blunted the parasympathetic-mediated diving reflex-evoked changes in heart rate. Neither spontaneous nor inspiratory-related inhibitory GABAergic or glycinergic neurotransmission to cardiac vagal neurons was altered by SO₂ exposure. However, excitatory glutamatergic neurotransmission was decreased by 51.2% upon SO₂ exposure. This diminished excitatory neurotransmission was tetrodotoxin-sensitive, indicating SO₂ exposure impaired the activity of preceding glutamatergic neurons that synapse upon cardiac vagal neurons. Diminished glutamatergic, but unaltered inhibitory neurotransmission to cardiac vagal neurons provides a mechanism for the observed SO₂-induced elevated heart rate via an impairment of brainstem cardioinhibitory parasympathetic activity to the heart.

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

Blockade of hyperpolarizing currents produces a dose-dependent effect on heart rate.

PubMed

Ziyatdinova, N I; Giniatullin, R A; Svyatova, N V; Zefirov, T L

2001-03-01

Intravenous injection of ZD 7288, a new specific hyperpolarizing current blocker, dose-dependently reduces heart rate in adult rats. The autonomic nervous system modulates changes in heart rate caused by hyperpolarizing currents.

Heart Rate During Sleep: Implications for Monitoring Training Status

PubMed Central

Waldeck, Miriam R.; Lambert, Michael I.

2003-01-01

Resting heart rate has sometimes been used as a marker of training status. It is reasonable to assume that the relationship between heart rate and training status should be more evident during sleep when extraneous factors that may influence heart rate are reduced. Therefore the aim of the study was to assess the repeatability of monitoring heart rate during sleep when training status remained unchanged, to determine if this measurement had sufficient precision to be used as a marker of training status. The heart rate of ten female subjects was monitored for 24 hours on three occasions over three weeks whilst training status remained unchanged. Average, minimum and maximum heart rate during sleep was calculated. The average heart rate of the group during sleep was similar on each of the three tests (65 ± 9, 63 ± 6 and 67 ± 7 beats·min-1 respectively). The range in minimum heart rate variation during sleep for all subjects over the three testing sessions was from 0 to 10 beats·min-1 (mean = 5 ± 3 beats·min-1) and for maximum heart rate variation was 2 to 31 beats·min-1 (mean = 13 ± 9 beats·min-1). In summary it was found that on an individual basis the minimum heart rate during sleep varied by about 8 beats·min-1. This amount of intrinsic day-to-day variation needs to be considered when changes in heart rate that may occur with changes in training status are interpreted. PMID:24688273

Simultaneous measurement of instantaneous heart rate and chest wall plethysmography in short-term, metronome guided heart rate variability studies: suitability for assessment of autonomic dysfunction.

PubMed

Perring, S; Jones, E

2003-08-01

Instantaneous heart rate and chest wall motion were measured using a 3-lead ECG and an air pressure chest wall plethysmography system. Chest wall plethysmography traces were found to accurately represent the breathing pattern as measured by spirometry (average correlation coefficient 0.944); though no attempt was made to calibrate plethysmography voltage output to tidal volume. Simultaneous measurements of heart rate and chest wall motion were made for short periods under metronome guided breathing at 6 breaths per minute. The average peak to trough heart rate change per breath cycle (AVEMAX) and maximum correlation between heart rate and breathing cycle (HRBRCORR) were measured. Studies of 44 normal volunteers indicated clear inverse correlation of heart rate variability parameters with age (AVEMAX R = -0.502, P < 0.001) but no significant change in HRBRCORR with age (R = -0.115). Comparison of normal volunteers with diabetics with no history of symptoms associated with autonomic failure indicated significant lower heart rate variability in diabetics (P = 0.005 for AVEMAX) and significantly worse correlation between heart rate and breathing (P < 0.001 for HRBRCORR). Simultaneous measurement of heart rate and breathing offers the possibility of more sensitive diagnosis of autonomic failure in a simple bedside test and gives further insight into the nature of cardio-ventilatory coupling.

Prediction of hypotension during spinal anesthesia for elective cesarean section by altered heart rate variability induced by postural change.

PubMed

Sakata, K; Yoshimura, N; Tanabe, K; Kito, K; Nagase, K; Iida, H

2017-02-01

Maternal hypotension is a common complication during cesarean section performed under spinal anesthesia. Changes in maternal heart rate with postural changes or values of heart rate variability have been reported to predict hypotension. Therefore, we hypothesized that changes in heart rate variability due to postural changes can predict hypotension. A total of 45 women scheduled to undergo cesarean section under spinal anesthesia were enrolled. A postural change test was performed the day before cesarean section. The ratio of the power of low and high frequency components contributing to heart rate variability was assessed in the order of supine, left lateral, and supine. Patients who exhibited a ⩾two-fold increase in the low-to-high frequency ratio when moving to supine from the lateral position were assigned to the postural change test-positive group. According to the findings of the postural change test, patients were assigned to the positive (n=22) and negative (n=23) groups, respectively. Hypotension occurred in 35/45 patients, of whom 21 (60%) were in the positive group and 14 (40%) were in the negative group. The incidence of hypotension was greater in the positive group (P<0.01). The total dose of ephedrine was greater in the positive group (15±11 vs. 7±7mg, P=0.005). The area under the receiver operating characteristic curve was 0.76 for the postural change test as a predictor of hypotension. The postural change test with heart rate variability analysis may be used to predict the risk of hypotension during spinal anesthesia for cesarean section. Copyright © 2016 Elsevier Ltd. All rights reserved.

Human Fetal Heart Rate Dishabituation between Thirty and Thirty-Two Weeks Gestation.

ERIC Educational Resources Information Center

Sandman, Curt A.; Wadhwa, Pathik; Hetrick, William; Porto, Manuel; Peeke, Harmon V. S.

1997-01-01

Examined the ability of 32-week human fetuses to learn and recall information. Found a significant heart rate habituation pattern for a series of vibroacoustic stimuli. After a single novel stimulus, the heart rate to stimulus 1 reemerged. Uterine contractions were not related to presentation of the novel stimulus or change in heart rate after the…

Perinatal sulfur dioxide exposure alters brainstem parasympathetic control of heart rate

PubMed Central

Woerman, Amanda L.; Mendelowitz, David

2013-01-01

Aims Sulfur dioxide (SO2) is an air pollutant that impedes neonatal development and induces adverse cardiorespiratory health effects, including tachycardia. Here, an animal model was developed that enabled characterization of (i) in vivo alterations in heart rate and (ii) altered activity in brainstem neurons that control heart rate after perinatal SO2 exposure. Methods and results Pregnant Sprague–Dawley dams and their pups were exposed to 5 parts per million SO2 for 1 h daily throughout gestation and 6 days postnatal. Electrocardiograms were recorded from pups at 5 days postnatal to examine changes in basal and diving reflex-evoked changes in heart rate following perinatal SO2 exposure. In vitro studies employed whole-cell patch-clamp electrophysiology to examine changes in neurotransmission to cardiac vagal neurons within the nucleus ambiguus upon SO2 exposure using a preparation that maintains fictive inspiratory activity recorded from the hypoglossal rootlet. Perinatal SO2 exposure increased heart rate and blunted the parasympathetic-mediated diving reflex-evoked changes in heart rate. Neither spontaneous nor inspiratory-related inhibitory GABAergic or glycinergic neurotransmission to cardiac vagal neurons was altered by SO2 exposure. However, excitatory glutamatergic neurotransmission was decreased by 51.2% upon SO2 exposure. This diminished excitatory neurotransmission was tetrodotoxin-sensitive, indicating SO2 exposure impaired the activity of preceding glutamatergic neurons that synapse upon cardiac vagal neurons. Conclusions Diminished glutamatergic, but unaltered inhibitory neurotransmission to cardiac vagal neurons provides a mechanism for the observed SO2-induced elevated heart rate via an impairment of brainstem cardioinhibitory parasympathetic activity to the heart. PMID:23504550

Effect of Stimulation of Neurotransmitter Systems on Heart Rate Variability and β-Adrenergic Responsiveness of Erythrocytes in Outbred Rats.

PubMed

Kur'yanova, E V; Tryasuchev, A V; Stupin, V O; Teplyi, D L

2017-05-01

We studied heart rate variability and β-adrenergic responsiveness of erythrocytes and changes in these parameters in response to single administration of β-adrenoblocker propranolol (2 mg/kg) in outbred male rats against the background of activation of the noradrenergic, serotonergic, and dopaminergic neurotransmitter systems achieved by 4-fold injections maprotiline (10 mg/kg), 5-hydroxytryptophan (50 mg/kg) combined with fluoxetine (3 mg/kg), and L-DOPA (20 mg/kg) with amantadine (20 mg/kg), respectively. Stimulation of the noradrenergic system moderately enhanced the heart rhythm rigidity and β-adrenergic responsiveness of erythrocytes. In addition, it markedly augmented the moderating effect of subsequently administered propranolol on LF and VLF components in the heart rate variability and reversed the effect of propranolol on β-adrenergic responsiveness of erythrocytes. Stimulation of the serotonergic system dramatically decreased all components in the heart rate variability and pronouncedly enhanced β-adrenergic responsiveness of erythrocytes. Subsequent injection of propranolol slightly restored all components in the heart rate variability and decreased β-adrenergic responsiveness of erythrocytes to the control level. Stimulation of the dopaminergic system made the heart rate more rigid due to decrease of all components in the heart rate variability; in addition, it slightly but significantly enhanced β-adrenergic responsiveness of erythrocytes. Subsequent injection of propranolol produced no significant effects on all components in the heart rate variability and on β-adrenergic responsiveness of erythrocytes. Stimulation of noradrenergic, serotonergic, and dopaminergic neurotransmitter systems produced unidirectional and consorted effects on heart rate variability and β-adrenergic responsiveness of erythrocytes, although the magnitudes of these effects were different. Probably, the changes in the heart rate variability in rats with stimulated neurotransmitter systems results from modification of the cellular sensitivity in peripheral organs to adrenergic influences. However, the differences in the reactions to β-adrenoblocker attest to specificity of the mechanisms underlying the changes in membrane reception and adrenergic pathways in every experimental model employed in this study.

Cardiovascular and Cerebrovascular Control on Return from International Space Station (CCISS)- Heart Rate and Activity

NASA Astrophysics Data System (ADS)

Hughson, R. L.; Shoemaker, J. K.; Blaber, A. P.; Arbeille, Ph.; Zuj, K. A.; Greaves, D. K.

2008-06-01

CCISS is a project to study the cardiovascular and cerebrovascular responses of astronauts before, during and after long-duration (>60-day) stays on the International Space Station. The CCISS experiments consist of three phases that are designed to achieve an integrated examination of components responsible for return of blood to the heart, the pumping of blood from the heart and the distribution to the vascular territories including the brain. In this report the data are obtained from the 24-h monitoring of physical activity (Actiwatch on wrist and ankle) and of heart rate (Holter monitor). The data show clear patterns of change in physical activity from predominantly leg-based on Earth to relatively little activity of the ankles with maintained or increased activity of the wrists on ISS. Both on Earth and on ISS the largest changes in heart rate occur during the periods of leg activity. Average heart rate was changed little during the periods of minimal activity or of sleep in comparisons of Earth with in-flight recording both within the first two weeks of flight and the last two weeks. These data clearly show the importance of monitoring heart rate and physical activity simultaneously and show that attempts to derive indicators of autonomic activity from spectral analysis of heart rate variability should not be performed in the absence of knowledge of both variables.

Olfactory bulbectomy induces rapid and stable changes in basal and stress-induced locomotor activity, heart rate and body temperature responses in the home cage.

PubMed

Vinkers, C H; Breuer, M E; Westphal, K G C; Korte, S M; Oosting, R S; Olivier, B; Groenink, L

2009-03-03

Olfactory bulbectomy (OBX) in rats causes several behavioral and neurochemical changes. However, the extent and onset of physiological and behavioral changes induced after bulbectomy have been little examined. Male Sprague-Dawley rats received telemetric implants. Before and immediately after OBX surgery, basal and stress-induced heart rate, body temperature, and locomotor activity were measured in the home cage in sham (n=9) and OBX animals (n=11). Stress was induced using novel cage stress or witness stress. Bulbectomized animals differed physiologically and behaviorally from shams. Nocturnally, OBX animals were significantly more active compared with shams, had a higher core body temperature and displayed a decreased heart rate variability. During the light period, OBX animals had a significantly lower basal heart rate and a reduced heart rate variability. These effects became apparent 2-3 days after OBX surgery, and were stable over time. After witness stress, OBX animals showed smaller autonomic (body temperature and heart rate) responses compared with shams, but showed no difference in locomotor responses. In contrast, novel cage stress led to increased locomotor responses in OBX rats compared with sham rats, while no differences were found in autonomic responses. Removal of the olfactory bulbs results in rapid, stable and persistent changes in basal locomotor activity, body temperature, heart rate and heart rate variability. Although the sleep-wake cycle of these parameters is not altered, increases in circadian amplitude are apparent within 3 days after surgery. This indicates that physiological changes in the OBX rat are the immediate result of olfactory bulb removal. Further, stress responsivity in OBX rats depends on stressor intensity. Bulbectomized rats display smaller temperature and heart rate responses to less intense witness stress compared with sham rats. Increased locomotor responses to more intense novel cage stress are present in the home cage as well as the open field. The present study shows that olfactory bulbectomy has rapid and persistent influence on basal and stress-induced physiological parameters.

Body position and activity, but not heart rate, affect pump flows in patients with continuous-flow left ventricular assist devices.

PubMed

Muthiah, Kavitha; Gupta, Sunil; Otton, James; Robson, Desiree; Walker, Robyn; Tay, Andre; Macdonald, Peter; Keogh, Anne; Kotlyar, Eugene; Granger, Emily; Dhital, Kumud; Spratt, Phillip; Jansz, Paul; Hayward, Christopher S

2014-08-01

The aim of this study was to determine the contribution of pre-load and heart rate to pump flow in patients implanted with continuous-flow left ventricular assist devices (cfLVADs). Although it is known that cfLVAD pump flow increases with exercise, it is unclear if this increment is driven by increased heart rate, augmented intrinsic ventricular contraction, or enhanced venous return. Two studies were performed in patients implanted with the HeartWare HVAD. In 11 patients, paced heart rate was increased to approximately 40 beats/min above baseline and then down to approximately 30 beats/min below baseline pacing rate (in pacemaker-dependent patients). Ten patients underwent tilt-table testing at 30°, 60°, and 80° passive head-up tilt for 3 min and then for a further 3 min after ankle flexion exercise. This regimen was repeated at 20° passive head-down tilt. Pump parameters, noninvasive hemodynamics, and 2-dimensional echocardiographic measures were recorded. Heart rate alteration by pacing did not affect LVAD flows or LV dimensions. LVAD pump flow decreased from baseline 4.9 ± 0.6 l/min to approximately 4.5 ± 0.5 l/min at each level of head-up tilt (p < 0.0001 analysis of variance). With active ankle flexion, LVAD flow returned to baseline. There was no significant change in flow with a 20° head-down tilt with or without ankle flexion exercise. There were no suction events. Centrifugal cfLVAD flows are not significantly affected by changes in heart rate, but they change significantly with body position and passive filling. Previously demonstrated exercise-induced changes in pump flows may be related to altered loading conditions, rather than changes in heart rate. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Changes in heart rate variability during the induction and decay of heat acclimation.

PubMed

Flouris, Andreas D; Poirier, Martin P; Bravi, Andrea; Wright-Beatty, Heather E; Herry, Christophe; Seely, Andrew J; Kenny, Glen P

2014-10-01

We evaluated the changes in core temperature, heart rate, and heart rate variability (HRV) during the induction and decay of heat acclimation. Ten males (23 ± 3 years; 79.5 ± 3.5 kg; 15.2 ± 4.5 percent body fat; 51.13 ± 4.61 mLO(2)∙kg(-1)∙min(-1) peak oxygen uptake) underwent a 14-day heat acclimation protocol comprising of 90-min cycling at ~50 % peak oxygen uptake at 40 °C and ~20 % relative humidity. Core temperature, heart rate, and 102 HRV measures were recorded during a heat tolerance test conducted at baseline (day 0) and at the end of the induction (day 14) and decay (day 28) phases. Heat acclimation resulted in significantly reduced core temperature [rectal (χ (2) = 1298.14, p < 0.001); esophageal (χ (2) = 1069.88, p < 0.001)] and heart rate (χ (2) = 1230.17, p < 0.001). Following the decay phase, 26, 40, and 60 % of the heat acclimation-induced reductions in rectal temperature, esophageal temperature, and heart rate, respectively, were lost. Heat acclimation was accompanied by profound and broad changes in HRV: at the end of the induction phase, 75 of the 102 variability measures computed were significantly different (p < 0.001), compared to only 47 of the 102 at the end of the decay phase. Heat acclimation is accompanied by reduced core temperature, significant bradycardia, and marked alterations in HRV, which we interpret as being related to vagal dominance. The observed changes in core temperature persist for at least 2 weeks of non-exposure to heat, while the changes in heart rate and HRV decay faster and are only partly evident after 2 weeks of non-exposure to heat.

Effects of chronic baroreceptor stimulation on the autonomic cardiovascular regulation in patients with drug-resistant arterial hypertension.

PubMed

Wustmann, Kerstin; Kucera, Jan P; Scheffers, Ingrid; Mohaupt, Markus; Kroon, Abraham A; de Leeuw, Peter W; Schmidli, Jürg; Allemann, Yves; Delacrétaz, Etienne

2009-09-01

In patients with drug-resistant hypertension, chronic electric stimulation of the carotid baroreflex is an investigational therapy for blood pressure reduction. We hypothesized that changes in cardiac autonomic regulation can be demonstrated in response to chronic baroreceptor stimulation, and we analyzed the correlation with blood pressure changes. Twenty-one patients with drug-resistant hypertension were prospectively included in a substudy of the Device Based Therapy in Hypertension Trial. Heart rate variability and heart rate turbulence were analyzed using 24-hour ECG. Recordings were obtained 1 month after device implantation with the stimulator off and after 3 months of chronic electric stimulation (stimulator on). Chronic baroreceptor stimulation decreased office blood pressure from 185+/-31/109+/-24 mm Hg to 154+/-23/95+/-16 mm Hg (P<0.0001/P=0.002). Mean heart rate decreased from 81+/-11 to 76+/-10 beats per minute(-1) (P=0.001). Heart rate variability frequency-domain parameters assessed using fast Fourier transformation (FFT; ratio of low frequency:high frequency: 2.78 versus 2.24 for off versus on; P<0.001) were significantly changed during stimulation of the carotid baroreceptor, and heart rate turbulence onset was significantly decreased (turbulence onset: -0.002 versus -0.015 for off versus on; P=0.004). In conclusion, chronic baroreceptor stimulation causes sustained changes in heart rate variability and heart rate turbulence that are consistent with inhibition of sympathetic activity and increase of parasympathetic activity in patients with drug-resistant systemic hypertension; these changes correlate with blood pressure reduction. Whether the autonomic modulation has favorable cardiovascular effects beyond blood pressure control should be investigated in further studies.

Acute Autonomic Engagement Assessed by Heart Rate Dynamics During Vagus Nerve Stimulation in Patients With Heart Failure in the ANTHEM-HF Trial.

PubMed

Nearing, Bruce D; Libbus, Imad; Amurthur, Badri; Kenknight, Bruce H; Verrier, Richard L

2016-09-01

Chronic vagus nerve stimulation (VNS) applied to produce biomimetic levels of parasympathetic activation is feasible, well tolerated, safe, improves left ventricular ejection fraction, NYHA class, heart rate variability, and baroreflex function, and reduces T-wave alternans (TWA) in patients with chronic heart failure. However, the acute effects of VNS on beat-to-beat heart rate dynamics have not been systematically characterized in humans. We evaluated acute effects of VNS on R-R-interval dynamics during the VNS titration period in patients (n = 59) enrolled in ANTHEM-HF trial by quantifying effects during continuous cyclic VNS (14-seconds on-time, 66-seconds off-time) adjusted to the maximum tolerable dose without excessive (<4 bpm) bradycardia during the 10-week titration period. VNS elicited an immediate change in heart rate that was correlated to VNS current amplitude, pulse width, and frequency. Heart rate decreased more in the 28 patients with right-sided stimulation (-2.22 ± 0.13 bpm) than in the 31 patients with left-sided stimulation (-0.60 ± 0.08 bpm, P < 0.001). The linear correlation between stimulus intensity and lengthening of the R-R interval was stronger among the 28 patients with right-sided VNS implantation (r = 0.88, P < 0.0001) than among the 31 patients with left-sided VNS implantation (r = 0.49, P < 0.002). In all patients, the heart rate change elicited by VNS was significantly greater than the change during the same timing intervals in 10 randomly selected patients without stimulation (+0.08 ± 0.06 bpm, P < 0.001). Instantaneous heart rate change during therapeutic levels of VNS in patients with heart failure indicates consistent modulation of the autonomic nervous system for both left- and right-sided stimulation. © 2016 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals, Inc.

Ventricular arrhythmias and changes in heart rate preceding ventricular tachycardia in patients with an implantable cardioverter defibrillator.

PubMed

Lerma, Claudia; Wessel, Niels; Schirdewan, Alexander; Kurths, Jürgen; Glass, Leon

2008-07-01

The objective was to determine the characteristics of heart rate variability and ventricular arrhythmias prior to the onset of ventricular tachycardia (VT) in patients with an implantable cardioverter defibrillator (ICD). Sixty-eight beat-to-beat time series from 13 patients with an ICD were analyzed to quantify heart rate variability and ventricular arrhythmias. The episodes of VT were classified in one of two groups depending on whether the sinus rate in the 1 min preceding the VT was greater or less than 90 beats per minute. In a subset of patients, increased heart rate and reduced heart rate variability was often observed up to 20 min prior to the VT. There was a non-significant trend to higher incidence of premature ventricular complexes (PVCs) before VT compared to control recordings. The patterns of the ventricular arrhythmias were highly heterogeneous among different patients and even within the same patient. Analysis of the changes of heart rate and heart rate variability may have predictive value about the onset of VT in selected patients. The patterns of ventricular arrhythmia could not be used to predict onset of VT in this group of patients.

Response time of mitochondrial oxygen consumption following stepwise changes in cardiac energy demand.

PubMed

van Beek, J H; Westerhof, N

1990-01-01

We determined the speed with which mitochondrial oxygen consumption and therefore the mitochondrial ATP-synthesis adapted to changes in metabolic demand in the rabbit heart. This was done by measuring the oxygen uptake of the whole heart during a stepwise change in heart rate and correcting for the time taken by diffusion and by convective transport in the blood vessels. Data for the correction for transport time were obtained from the response of venous oxygen concentration to a stepwise change of arterial oxygen concentration. The time constant of the response of mitochondrial oxygen consumption to a step change in heart rate was found to be 4-8 s.

Effects of changing ambient temperature on metabolic, heart, and ventilation rates during steady state hibernation in golden-mantled ground squirrels (Spermophilus lateralis).

PubMed

Zimmer, M B; Milsom, W K

2001-01-01

To determine whether metabolic rate is suppressed in a temperature-independent fashion in the golden-mantled ground squirrel during steady state hibernation, we measured body temperature and metabolic rate in ground squirrels during hibernation at different T(a)'s. In addition, we attempted to determine whether heart rate, ventilation rate, and breathing patterns changed as a function of body temperature or metabolic rate. We found that metabolic rate changed with T(a) as it was raised from 5 degrees to 14 degrees C, which supports the theory that different species sustain falls in metabolic rate during hibernation in different ways. Heart rate and breathing pattern also changed with changing T(a), while breathing frequency did not. That the total breathing frequency did not correlate closely with oxygen consumption or body temperature, while the breathing pattern did, raises important questions regarding the mechanisms controlling ventilation during hibernation.

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

PubMed

Kochiya, Yuko; Hirabayashi, Akari; Ichimaru, Yuhei

2017-09-16

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

Heart Rates of Elite Synchronized Swimmers.

ERIC Educational Resources Information Center

Gemma, Karen Erickson; Wells, Christine L.

1987-01-01

Heart rates were recorded by radiotelemetry in ten elite and national-class synchronized swimmers as they performed competitive figures of high degrees of difficulty. The focus was on changes in heart rates and electrocardiogram patterns for each body position, especially those requiring facial immersion and breath-holding. (Author/MT)

Patterns of Interspecific Variation in the Heart Rates of Embryonic Reptiles

PubMed Central

Du, Wei-Guo; Ye, Hua; Zhao, Bo; Pizzatto, Ligia; Ji, Xiang; Shine, Richard

2011-01-01

New non-invasive technologies allow direct measurement of heart rates (and thus, developmental rates) of embryos. We applied these methods to a diverse array of oviparous reptiles (24 species of lizards, 18 snakes, 11 turtles, 1 crocodilian), to identify general influences on cardiac rates during embryogenesis. Heart rates increased with ambient temperature in all lineages, but (at the same temperature) were faster in lizards and turtles than in snakes and crocodilians. We analysed these data within a phylogenetic framework. Embryonic heart rates were faster in species with smaller adult sizes, smaller egg sizes, and shorter incubation periods. Phylogenetic changes in heart rates were negatively correlated with concurrent changes in adult body mass and residual incubation period among the lizards, snakes (especially within pythons) and crocodilians. The total number of embryonic heart beats between oviposition and hatching was lower in squamates than in turtles or the crocodilian. Within squamates, embryonic iguanians and gekkonids required more heartbeats to complete development than did embryos of the other squamate families that we tested. These differences plausibly reflect phylogenetic divergence in the proportion of embryogenesis completed before versus after laying. PMID:22174948

Respiration and heart rate complexity: Effects of age and gender assessed by band-limited transfer entropy

PubMed Central

Nemati, Shamim; Edwards, Bradley A.; Lee, Joon; Pittman-Polletta, Benjamin; Butler, James P.; Malhotra, Atul

2013-01-01

Aging and disease are accompanied with a reduction of complex variability in the temporal patterns of heart rate. This reduction has been attributed to a break down of the underlying regulatory feedback mechanisms that maintain a homeodynamic state. Previous work has established the utility of entropy as an index of disorder, for quantification of changes in heart rate complexity. However, questions remain regarding the origin of heart rate complexity and the mechanisms involved in its reduction with aging and disease. In this work we use a newly developed technique based on the concept of band-limited transfer entropy to assess the aging-related changes in contribution of respiration and blood pressure to entropy of heart rate at different frequency bands. Noninvasive measurements of heart beat interval, respiration, and systolic blood pressure were recorded from 20 young (21–34 years) and 20 older (68–85 years) healthy adults. Band-limited transfer entropy analysis revealed a reduction in high-frequency contribution of respiration to heart rate complexity (p < 0.001) with normal aging, particularly in men. These results have the potential for dissecting the relative contributions of respiration and blood pressure-related reflexes to heart rate complexity and their degeneration with normal aging. PMID:23811194

Effect of hypokinesia on cardiac contractile function and nervous regulation of the heart

NASA Technical Reports Server (NTRS)

Meyerson, F. Z.; Kapelko, V. I.; Gorina, M. S.; Shchegolkov, A. N.; Larinov, N. P.

1980-01-01

Longterm hypokinesia caused cardiac deadaptation in rabbits, which resulted in the diminishing of the left ventricular rate of contraction and relaxation, joined later by decreased vascular resistance. As a results, the ejection rate as well as stroke volume and cardiac output were normal. The decrease of the relaxation speed was more obvious at a high heart rate and results in shortening of the diastolic pause and diminishing of cardiac output. Hearts of the hypokinetic animals were characterized by normal maximal pressure developed by a unit of muccardial mass aorta clamping, decreased adrenoreactivity, and increased cholinoreactivity. This complex of changes is contrary to changes observed in adaptation to exercise, but is similar to changes observed in compensatory hypertrophy of the heart.

[Study of blood oxygen saturation, heart rate changes and plateau reaction of the Antarctic Kunlun station investigation team in different plateau environments].

PubMed

Zhao, Shun-yun; Wu, Xin-min; Guo, Ya-min; Zhang, Shu-shun; An, Yan-ming; Li, Bing; Wang, Hao

2013-06-11

To explore the blood oxygen saturation and heart rate changes of the Antarctic explorers. During August 2010 to April 2011, the changes in blood oxygen saturation, heart rate and plateau reaction of 16 Antarctic expedition team in different plateau environments (Tibetan plateau versus Antarctic plateau) were monitored with the noninvasive pulse oximeter MD300-C. The extent of acute mountain sickness was determined according to the Lake Louise Consensus acute mountain reaction symptom scores and judgment method. The changes of blood oxygen saturation, heart rate at different altitudes of 110, 3650, 4300 m (96.8% ± 1.2%,89.1% ± 1.2%, 86.1% ± 2.0%, (75.0 ± 5.4) times/min, (104.0 ± 4.3) times/min, (113.0 ± 5.2) times/min,F = 214.155, 240.088,both P < 0.05). With rising latitude and elevation gradient in Antarctic plateau, the changes of blood oxygen saturation, heart rate at different altitudes of 2000, 2500, 3000, 3500 and 4087 m(91.9% ± 1.3%,90.5% ± 1.3%,87.6% ± 1.4%,85.0% ± 1.8%,81.5% ± 2.2%, (85.9 ± 3.2) times/min, (90.6 ± 2.8) times/min, (97.8 ± 4.1) times/min, (102.0 ± 3.4) times/min, (106.3 ± 3.9) times/min, F = 105.418, 90.174, both P < 0.05). Levels of blood oxygen saturation and heart rate were both correlated with the risk of altitude sickness (r = -0.446 and 0.565, both P < 0.05). As the increases of altitude, there are significant changes in oxygen saturation, heart rate of the Antarctic explorers. And with the increases of altitude, the risk of altitude sickness gradually increases.

Effects of head-down bed rest on complex heart rate variability: Response to LBNP testing

NASA Technical Reports Server (NTRS)

Goldberger, Ary L.; Mietus, Joseph E.; Rigney, David R.; Wood, Margie L.; Fortney, Suzanne M.

1994-01-01

Head-down bed rest is used to model physiological changes during spaceflight. We postulated that bed rest would decrease the degree of complex physiological heart rate variability. We analyzed continuous heart rate data from digitized Holter recordings in eight healthy female volunteers (age 28-34 yr) who underwent a 13-day 6 deg head-down bed rest study with serial lower body negative pressure (LBNP) trials. Heart rate variability was measured on a 4-min data sets using conventional time and frequency domain measures as well as with a new measure of signal 'complexity' (approximate entropy). Data were obtained pre-bed rest (control), during bed rest (day 4 and day 9 or 11), and 2 days post-bed rest (recovery). Tolerance to LBNP was significantly reduced on both bed rest days vs. pre-bed rest. Heart rate variability was assessed at peak LBNP. Heart rate approximate entropy was significantly decreased at day 4 and day 9 or 11, returning toward normal during recovery. Heart rate standard deviation and the ratio of high- to low-power frequency did not change significantly. We conclude that short-term bed rest is associated with a decrease in the complex variability of heart rate during LBNP testing in healthy young adult women. Measurement of heart rate complexity, using a method derived from nonlinear dynamics ('chaos theory'), may provide a sensitive marker of this loss of physiological variability, complementing conventional time and frequency domain statistical measures.

Win some, lose some: parental hypertension and heart rate change in an incentive versus response cost paradigm.

PubMed

Hastrup, J L; Johnson, C A; Hotchkiss, A P; Kraemer, D L

1986-11-01

Fowles (1983), citing evidence from separate studies, suggests that both incentive and response cost paradigms increase heart rate and should be subsumed under Gray's (1975) 'appetitive motivational system'. Shock avoidance and loss of reward (response cost) contingencies, while aversive, appear to evoke this motivational system; consequently both should elicit heart rate increases independent of anxiety. The present investigation compared magnitude of heart rate changes observed under conditions of winning and losing money. Results showed: no differences between incentive and response cost conditions; no effect of state anxiety on heart rate in these conditions, despite an elevation of state anxiety on the task day relative to a subsequent relaxation day assessment; and some evidence for the presence under both such appetitive conditions of cardiovascular hyperresponsivity among offspring of hypertensive parents. The results suggest a need for systematic parametric studies of experimental conditions.

The influence of betamethasone on fetal heart rate variability, obtained by non-invasive fetal electrocardiogram recordings.

PubMed

Verdurmen, Kim M J; Warmerdam, Guy J J; Lempersz, Carlijn; Hulsenboom, Alexandra D J; Renckens, Joris; Dieleman, Jeanne P; Vullings, Rik; van Laar, Judith O E H; Oei, S Guid

2018-04-01

Betamethasone is widely used to enhance fetal lung maturation in case of threatened preterm labour. Fetal heart rate variability is one of the most important parameters to assess in fetal monitoring, since it is a reliable indicator for fetal distress. To describe the effect of betamethasone on fetal heart rate variability, by applying spectral analysis on non-invasive fetal electrocardiogram recordings. Prospective cohort study. Patients that require betamethasone, with a gestational age from 24 weeks onwards. Fetal heart rate variability parameters on day 1, 2, and 3 after betamethasone administration are compared to a reference measurement. Following 68 inclusions, 12 patients remained with complete series of measurements and sufficient data quality. During day 1, an increase in absolute fetal heart rate variability values was seen. During day 2, a decrease in these values was seen. All trends indicate to return to pre-medication values on day 3. Normalised high- and low-frequency power show little changes during the study period. The changes in fetal heart rate variability following betamethasone administration show the same pattern when calculated by spectral analysis of the fetal electrocardiogram, as when calculated by cardiotocography. Since normalised spectral values show little changes, the influence of autonomic modulation seems minor. Copyright © 2018 Elsevier B.V. All rights reserved.

Changes in heart rate associated with contest outcome in agonistic encounters in lobsters.

PubMed

Hernáindez-Falcón, Jesús; Basu, Alo C; Govindasamy, Siddhartan; Kravitz, Edward A

2005-03-01

Agonistic contests between lobsters housed together in a confined space progress through encounters of increasing intensity until a dominance relationship is established. Once this relationship is established, losing animals continually retreat from the advances of winners. These encounters are likely to consume much energy in both winning and losing animals. Therefore, one might expect involvement of many physiological systems before, during and after fights. Here, we report effects of agonistic encounters on cardiac frequency in winning and losing adult lobsters involved in dyadic interactions. The results show that: (i) small but significant increases in heart rate are observed upon chemical detection of a conspecific; (ii) during agonistic interactions, further increases in heart rate are seen; and (iii) ultimate winners exhibit greater increases in heart rate lasting longer periods of time compared to ultimate losers. Heart rate in winners remains elevated for at least 15 min after the contests have ended and animals have been returned to their home tanks. Reduced effects are seen in second and third pairings between familiar opponents. The sustained changes in heart rate that we observe in winning lobsters may result from hormonal modulation of cardiac function related to the change in social status brought about by contest outcome.

Isoflurane increases cardiorespiratory coordination in rats

NASA Astrophysics Data System (ADS)

Kabir, Muammar M.; Beig, Mirza I.; Nalivaiko, Eugene; Abbott, Derek; Baumert, Mathias

2008-12-01

Anesthetics such as isoflurane adversely affect heart rate. In this study we analysed the interaction between heart rhythm and respiration at different concentrations of isoflurane and ventilation rates. In two rats, the electrocardiogram (ECG) and respiratory signals were recorded under the influence of isoflurane. For the assessment of cardiorespiratory coordination, we analysed the phase locking between heart rate, computed from the R-R intervals of body surface ECG, and respiratory rate, computed from impedance changes, using Hilbert transform. The changes in heart rate, percentage of synchronization and duration of synchronized epochs at different isoflurane concentrations and ventilation rates were assessed using linear regression model. From this study it appears that the amount of phase locking between cardiac and respiratory rates increases with the increase in concentration of isoflurane. Heart rate and duration of synchronized epochs increased significantly with the increase in the level of isoflurane concentration while respiratory rate was not significantly affected. Cardiorespiratory coordination also showed a considerable increase at the ventilation rates of 50- 55 cpm in both the rats, suggesting that the phase-locking between the cardiac and respiratory oscillators can be increased by breathing at a particular respiratory frequency.

Features of Heart Rate Variability Capture Regulatory Changes During Kangaroo Care in Preterm Infants.

PubMed

Kommers, Deedee R; Joshi, Rohan; van Pul, Carola; Atallah, Louis; Feijs, Loe; Oei, Guid; Bambang Oetomo, Sidarto; Andriessen, Peter

2017-03-01

To determine whether heart rate variability (HRV) can serve as a surrogate measure to track regulatory changes during kangaroo care, a period of parental coregulation distinct from regulation within the incubator. Nurses annotated the starting and ending times of kangaroo care for 3 months. The pre-kangaroo care, during-kangaroo care, and post-kangaroo care data were retrieved in infants with at least 10 accurately annotated kangaroo care sessions. Eight HRV features (5 in the time domain and 3 in the frequency domain) were used to visually and statistically compare the pre-kangaroo care and during-kangaroo care periods. Two of these features, capturing the percentage of heart rate decelerations and the extent of heart rate decelerations, were newly developed for preterm infants. A total of 191 kangaroo care sessions were investigated in 11 preterm infants. Despite clinically irrelevant changes in vital signs, 6 of the 8 HRV features (SD of normal-to-normal intervals, root mean square of the SD, percentage of consecutive normal-to-normal intervals that differ by >50 ms, SD of heart rate decelerations, high-frequency power, and low-frequency/high-frequency ratio) showed a visible and statistically significant difference (P <.01) between stable periods of kangaroo care and pre-kangaroo care. HRV was reduced during kangaroo care owing to a decrease in the extent of transient heart rate decelerations. HRV-based features may be clinically useful for capturing the dynamic changes in autonomic regulation in response to kangaroo care and other changes in environment and state. Copyright © 2016 Elsevier Inc. All rights reserved.

[Heart rate variability of subjects when the instruction reading and their interrelations with the effectiveness of the follow-visual-motor activities].

PubMed

Murtazina, E P

2015-01-01

Investigation of the processes of studying human instructions relevant follow-up in terms of systemic mechanisms of learning and memory processes, and moreover affects such a fundamental issue as psychophysiology focused attention, understanding the meaning of the information provided and the formation of social motivation in human activities. Analysis of heart rate variability in reading the instructions compared to the initial state of operational rest showed that this stage of the activity causes pronounced emotional stress, which is manifested in increased heart rate, decrease in variability and pronounced changes in the spectral characteristics of heart rate. Besides, it was revealed that heart rate variability in a state of operational rest before testing, and in the process of reading instructions positively correlated with the duration of the instruction reading and inversely correlated with effectiveness and the level of resistance of the subjects to the error after error when follow-up activities. Showing pronounced gender differences in the relationships between changes in the variability of heart rate when reading the instructions and the subsequent execution indicators of visual-motor test.

Reduced intrinsic heart rate is associated with reduced arrhythmic susceptibility in guinea-pig heart.

PubMed

Osadchii, Oleg E

2014-12-01

In the clinical setting, patients with slower resting heart rate are less prone to cardiovascular death compared with those with elevated heart rate. However, electrophysiological adaptations associated with reduced cardiac rhythm have not been thoroughly explored. In this study, relationships between intrinsic heart rate and arrhythmic susceptibility were examined by assessments of action potential duration (APD) rate adaptation and inducibility of repolarization alternans in sinoatrial node (SAN)-driven and atrioventricular (AV)-blocked guinea-pig hearts perfused with Langendorff apparatus. Electrocardiograms, epicardial monophasic action potentials, and effective refractory periods (ERP) were assessed in normokalemic and hypokalemic conditions. Slower basal heart rate in AV-blocked hearts was associated with prolonged ventricular repolarization during spontaneous beating, and with attenuated APD shortening at increased cardiac activation rates during dynamic pacing, when compared with SAN-driven hearts. During hypokalemic perfusion, the inducibility of repolarization alternans and tachyarrhythmia by rapid pacing was found to be lower in AV-blocked hearts. This difference was ascribed to prolonged ERP in the setting of reduced basal heart rate, which prevented ventricular capture at critically short pacing intervals required to induce arrhythmia. Reduced basal heart rate is associated with electrophysiological changes that prevent electrical instability upon an abrupt cardiac acceleration.

Using time-frequency analysis of the photoplethysmographic waveform to detect the withdrawal of 900 mL of blood.

PubMed

Scully, Christopher G; Selvaraj, Nandakumar; Romberg, Frederick W; Wardhan, Richa; Ryan, John; Florian, John P; Silverman, David G; Shelley, Kirk H; Chon, Ki H

2012-07-01

We designed this study to determine if 900 mL of blood withdrawal during spontaneous breathing in healthy volunteers could be detected by examining the time-varying spectral amplitude of the photoplethysmographic (PPG) waveform in the heart rate frequency band and/or in the breathing rate frequency band before significant changes occurred in heart rate or arterial blood pressure. We also identified the best PPG probe site for early detection of blood volume loss by testing ear, finger, and forehead sites. Eight subjects had 900 mL of blood withdrawn followed by reinfusion of 900 mL of blood. Physiological monitoring included PPG waveforms from ear, finger, and forehead probe sites, standard electrocardiogram, and standard blood pressure cuff measurements. The time-varying amplitude sequences in the heart rate frequency band and breathing rate frequency band present in the PPG waveform were extracted from high-resolution time-frequency spectra. These amplitudes were used as a parameter for blood loss detection. Heart rate and arterial blood pressure did not significantly change during the protocol. Using time-frequency analysis of the PPG waveform from ear, finger, and forehead probe sites, the amplitude signal extracted at the frequency corresponding to the heart rate significantly decreased when 900 mL of blood was withdrawn, relative to baseline (all P < 0.05); for the ear, the corresponding signal decreased when only 300 mL of blood was withdrawn. The mean percent decrease in the amplitude of the heart rate component at 900 mL blood loss relative to baseline was 45.2% (38.2%), 42.0% (29.2%), and 42.3% (30.5%) for ear, finger, and forehead probe sites, respectively, with the lower 95% confidence limit shown in parentheses. After 900 mL blood reinfusion, the amplitude signal at the heart rate frequency showed a recovery towards baseline. There was a clear separation of amplitude values at the heart rate frequency between baseline and 900 mL blood withdrawal. Specificity and sensitivity were both found to be 87.5% with 95% confidence intervals (47.4%, 99.7%) for ear PPG signals for a chosen threshold value that was optimized to separate the 2 clusters of amplitude values (baseline and blood loss) at the heart rate frequency. Meanwhile, no significant changes in the spectral amplitude in the frequency band corresponding to respiration were found. A time-frequency spectral method detected blood loss in spontaneously breathing subjects before the onset of significant changes in heart rate or blood pressure. Spectral amplitudes at the heart rate frequency band were found to significantly decrease during blood loss in spontaneously breathing subjects, whereas those at the breathing rate frequency band did not significantly change. This technique may serve as a valuable tool in intraoperative and trauma settings to detect and monitor hemorrhage.

Peri-ictal ECG changes in childhood epilepsy: implications for detection systems.

PubMed

Jansen, Katrien; Varon, Carolina; Van Huffel, Sabine; Lagae, Lieven

2013-10-01

Early detection of seizures could reduce associated morbidity and mortality and improve the quality of life of patients with epilepsy. In this study, the aim was to investigate whether ictal tachycardia is present in focal and generalized epileptic seizures in children. We sought to predict in which type of seizures tachycardia can be identified before actual seizure onset. Electrocardiogram segments in 80 seizures were analyzed in time and frequency domains before and after the onset of epileptic seizures on EEG. These ECG parameters were analyzed to find the most informative ones that can be used for seizure detection. The algorithm of Leutmezer et al. was used to find the temporal relationship between the change in heart rate and seizure onset. In the time domain, the mean RR shows a significant difference before compared to after onset of the seizure in focal seizures. This can be observed in temporal lobe seizures as well as frontal lobe seizures. Calculation of mean RR interval has a high specificity for detection of ictal heart rate changes. Preictal heart rate changes are observed in 70% of the partial seizures. Ictal heart rate changes are present only in partial seizures in this childhood epilepsy study. The changes can be observed in temporal lobe seizures as well as in frontal lobe seizures. Heart rate changes precede seizure onset in 70% of the focal seizures, making seizure detection and closed-loop systems a possible therapeutic alternative in the population of children with refractory epilepsy. © 2013.

Heart Rate and Blood Pressure Variability under Moon, Mars and Zero Gravity Conditions During Parabolic Flights

NASA Astrophysics Data System (ADS)

Aerts, Wouter; Joosen, Pieter; Widjaja, Devy; Varon, Carolina; Vandeput, Steven; Van Huffel, Sabine; Aubert, Andre E.

2013-02-01

Gravity changes during partial-G parabolic flights (0g -0.16g - 0.38g) lead to changes in modulation of the autonomic nervous system (ANS), studied via the heart rate variability (HRV) and blood pressure variability (BPV). HRV and BPV were assessed via classical time and frequency domain measures. Mean systolic and diastolic blood pressure show both increasing trends towards higher gravity levels. The parasympathetic and sympathetic modulation show both an increasing trend with decreasing gravity, although the modulation is sympathetic predominant during reduced gravity. For the mean heart rate, a non-monotonic relation was found, which can be explained by the increased influence of stress on the heart rate. This study shows that there is a relation between changes in gravity and modulations in the ANS. With this in mind, countermeasures can be developed to reduce postflight orthostatic intolerance.

Examining the Influence of Heartbeat on Expert Marksman Performance

DTIC Science & Technology

2016-04-01

factors, such as heartbeat and heart rate, may play a role on a marksman’s shot as well. For instance, work has been done to determine the effect of... heart rate on expert marksmanship. The results of that work show that an expert marksman’s performance did not change in regard to heart rate. (Pojman...marksmanship phase. (The ECG values are not to be confused with the heart rate, which is the frequency of the cardiac cycle.) The heartbeat on an ECG is

Oxygen saturation and heart rate during feeding in breast-fed infants at 1 week and 2 months of age.

PubMed

Suiter, Debra M; Ruark-McMurtrey, Jacki

2007-12-01

To gather normative data about cardiopulmonary changes during feeding in breast-fed infants at 1 week and 2 months of age. Prospective cohort study. General community. Twenty-two term-born, breast-fed infants. Not applicable. Oxygen saturation (SpO2), the percentage of oxygenized hemoglobin, and heart rate were monitored and recorded every 30 seconds for 5 minutes before oral feeding, during the first 10 minutes of feeding, and the first 10 minutes immediately after feeding. The observations were made at 1 week and 2 months of age. Mean SpO2 levels were significantly higher in 2-month-old infants (mean, 97.57) than in 1-week-old infants (mean, 96.35) (P=.001). SpO2 was not affected by any of the 3 trials (before, during, and after feeding). Heart rate was significantly affected by trial. Mean heart rate during feeding (mean, 152.45) was significantly higher than heart rate prefeeding (mean, 146.51) (P<.001), and heart rate postfeeding (mean, 147.12) (P=.002). Heart rate was not affected by age. Little is known about the association between feeding and cardiopulmonary status in term-born, breast-fed infants. This longitudinal study contributes to our knowledge about feeding-related cardiopulmonary changes in term-born, breast-fed infants.

A new approach to correct the QT interval for changes in heart rate using a nonparametric regression model in beagle dogs.

PubMed

Watanabe, Hiroyuki; Miyazaki, Hiroyasu

2006-01-01

Over- and/or under-correction of QT intervals for changes in heart rate may lead to misleading conclusions and/or masking the potential of a drug to prolong the QT interval. This study examines a nonparametric regression model (Loess Smoother) to adjust the QT interval for differences in heart rate, with an improved fitness over a wide range of heart rates. 240 sets of (QT, RR) observations collected from each of 8 conscious and non-treated beagle dogs were used as the materials for investigation. The fitness of the nonparametric regression model to the QT-RR relationship was compared with four models (individual linear regression, common linear regression, and Bazett's and Fridericia's correlation models) with reference to Akaike's Information Criterion (AIC). Residuals were visually assessed. The bias-corrected AIC of the nonparametric regression model was the best of the models examined in this study. Although the parametric models did not fit, the nonparametric regression model improved the fitting at both fast and slow heart rates. The nonparametric regression model is the more flexible method compared with the parametric method. The mathematical fit for linear regression models was unsatisfactory at both fast and slow heart rates, while the nonparametric regression model showed significant improvement at all heart rates in beagle dogs.

Association Between Energy Prices and US Hospital Patient Outcomes.

PubMed

Brown, Lawrence H; Chaiechi, Taha; Buettner, Petra G; Canyon, Deon V

2017-04-01

To evaluate associations between changing energy prices and US hospital patient outcomes. Generalized estimating equations were used to analyze relationships between changes in energy prices and subsequent changes in hospital patient outcomes measures for the years 2008 through 2014. Patient outcomes measures included 30-day acute myocardial infarction, heart failure, and pneumonia mortality rates, and 30-day acute myocardial infarction, heart failure, and pneumonia readmission rates. Energy price data included state average distillate fuel, electricity and natural gas prices, and the US average coal price. All of the price data were converted to 2014 dollars using Consumer Price Index multipliers. There was a significant positive association between changes in coal price and both short-term ( P = 0.029) and long-term ( P = 0.017) changes in the 30-day heart failure mortality rate. There was a similar significant positive association between changes in coal price and both short-term ( P <0.001) and long-term ( P = 0.002) changes in the 30-day pneumonia mortality rate. Changes in coal prices also were positively associated with long-term changes in the 30-day myocardial infarction readmission rate ( P < 0.001). Changes in coal prices ( P = 0.20), natural gas prices ( P = 0.040), and electricity prices ( P = 0.040) were positively associated with long-term changes in the 30-day heart failure readmission rate. Changing energy prices are associated with subsequent changes in hospital mortality and readmission measures. In light of these data, we encourage hospital, health system, and health policy leaders to pursue patient-support initiatives, energy conservation programs, and reimbursement policy strategies aimed at mitigating those effects.

Noncontact measurement of emotional and physiological changes in heart rate from a webcam.

PubMed

Madan, Christopher R; Harrison, Tyler; Mathewson, Kyle E

2018-04-01

Heart rate, measured in beats per minute, can be used as an index of an individual's physiological state. Each time the heart beats, blood is expelled and travels through the body. This blood flow can be detected in the face using a standard webcam that is able to pick up subtle changes in color that cannot be seen by the naked eye. Due to the light absorption spectrum of blood, we are able to detect differences in the amount of light absorbed by the blood traveling just below the skin (i.e., photoplethysmography). By modulating emotional and physiological stress-that is, viewing arousing images and sitting versus standing, respectively-to elicit changes in heart rate, we explored the feasibility of using a webcam as a psychophysiological measurement of autonomic activity. We found a high level of agreement between established physiological measures, electrocardiogram, and blood pulse oximetry, and heart rate estimates obtained from the webcam. We thus suggest webcams can be used as a noninvasive and readily available method for measuring psychophysiological changes, easily integrated into existing stimulus presentation software and hardware setups. © 2017 Society for Psychophysiological Research.

Cardiovascular responses associated with daily walking in subacute stroke.

PubMed

Prajapati, Sanjay K; Mansfield, Avril; Gage, William H; Brooks, Dina; McIlroy, William E

2013-01-01

Despite the importance of regaining independent ambulation after stroke, the amount of daily walking completed during in-patient rehabilitation is low. The purpose of this study is to determine if (1) walking-related heart rate responses reached the minimum intensity necessary for therapeutic aerobic exercise (40%-60% heart rate reserve) or (2) heart rate responses during bouts of walking revealed excessive workload that may limit walking (>80% heart rate reserve). Eight individuals with subacute stroke attending in-patient rehabilitation were recruited. Participants wore heart rate monitors and accelerometers during a typical rehabilitation day. Walking-related changes in heart rate and walking bout duration were determined. Patients did not meet the minimum cumulative requirements of walking intensity (>40% heart rate reserve) and duration (>10 minutes continuously) necessary for cardiorespiratory benefit. Only one patient exceeded 80% heart rate reserve. The absence of significant increases in heart rate associated with walking reveals that patients chose to walk at speeds well below a level that has meaningful cardiorespiratory health benefits. Additionally, cardiorespiratory workload is unlikely to limit participation in walking. Measurement of heart rate and walking during in-patient rehabilitation may be a useful approach to encourage patients to increase the overall physical activity and to help facilitate recovery.

Cardio-Pulmonary Stethoscope: Clinical Validation With Heart Failure and Hemodialysis Patients.

PubMed

Iskander, Magdy F; Seto, Todd B; Perron, Ruthsenne Rg; Lim, Eunjung; Qazi, Farhan

2018-05-01

The purpose of this study is to evaluate the accuracy of a noninvasive radiofrequency-based device, the Cardio-Pulmonary Stethoscope (CPS), to monitor heart and respiration rates, and detect changes in lung water content in human experiments and clinical trials. Three human populations (healthy subjects ( ), heart failure (), and hemodialysis () patients) were enrolled in this study. The study was conducted at the University of Hawaii and the Queen's Medical Center in Honolulu, HI, USA. Measurement of heart and respiration rates for all patients was compared with standard FDA - approved monitoring methods. For lung water measurements, CPS data were compared with simultaneous pulmonary capillary wedge pressure (PCWP) measurements for heart failure patients, and with change in weight of extracted fluid for hemodialysis patients. Statistical correlation methods (Pearson, mixed, and intraclass) were used to compare the data and examine accuracy of CPS results. Results show that heart and respiration rates of all patients have excellent correlation factors, r≥0.9. Comparisons with fluid removed during hemodialysis treatment showed correlation factor of to 1, while PCWP measurements of heart failure patients had correlation factor of to 0.97. These results suggest that CPS technology accurately quantifies heart and respiration rates and measure fluid changes in the lungs. The CPS has the potential to accurately monitor lung fluid status noninvasively and continuously in a clinical and outpatient setting. Early and efficient management of lung fluid status is key in managing chronic conditions such heart failure, pulmonary hypertension, and acute respiration distress syndrome.

Redistribution of blood within the body is important for thermoregulation in an ectothermic vertebrate (Crocodylus porosus).

PubMed

Seebacher, Frank; Franklin, Craig E

2007-11-01

Changes in blood flow are a principal mechanism of thermoregulation in vertebrates. Changes in heart rate will alter blood flow, although multiple demands for limited cardiac output may compromise effective thermoregulation. We tested the hypothesis that regional differences in blood flow during heating and cooling can occur independently from changes in heart rate. We measured heart rate and blood pressure concurrently with blood flow in the crocodile, Crocodylus porosus. We measured changes in blood flow by laser Doppler flowmetry, and by injecting coloured microspheres. All measurements were made under different heat loads, with and without blocking cholinergic and beta-adrenergic receptors (autonomic blockade). Heart rates were significantly faster during heating than cooling in the control animals, but not when autonomic receptors were blocked. There were no significant differences in blood flow distribution between the control and autonomic blockade treatments. In both treatments, blood flow was directed to the dorsal skin and muscle and away from the tail and duodenum during heating. When the heat source was switched off, there was a redistribution of blood from the dorsal surface to the duodenum. Blood flow to the leg skin and muscle, and to the liver did not change significantly with thermal state. Blood pressure was significantly higher during the autonomic blockade than during the control. Thermal time constants of heating and cooling were unaffected by the blockade of autonomic receptors. We concluded that animals partially compensated for a lack of differential heart rates during heating and cooling by redistributing blood within the body, and by increasing blood pressure to increase flow. Hence, measures of heart rate alone are insufficient to assess physiological thermoregulation in reptiles.

Changes in the Geographic Patterns of Heart Disease Mortality in the United States: 1973 to 2010.

PubMed

Casper, Michele; Kramer, Michael R; Quick, Harrison; Schieb, Linda J; Vaughan, Adam S; Greer, Sophia

2016-03-22

Although many studies have documented the dramatic declines in heart disease mortality in the United States at the national level, little attention has been given to the temporal changes in the geographic patterns of heart disease mortality. Age-adjusted and spatially smoothed county-level heart disease death rates were calculated for 2-year intervals from 1973 to 1974 to 2009 to 2010 for those aged ≥35 years. Heart disease deaths were defined according to the International Classification of Diseases codes for diseases of the heart in the eighth, ninth, and tenth revisions of the International Classification of Diseases. A fully Bayesian spatiotemporal model was used to produce precise rate estimates, even in counties with small populations. A substantial shift in the concentration of high-rate counties from the Northeast to the Deep South was observed, along with a concentration of slow-decline counties in the South and a nearly 2-fold increase in the geographic inequality among counties. The dramatic change in the geographic patterns of heart disease mortality during 40 years highlights the importance of small-area surveillance to reveal patterns that are hidden at the national level, gives communities the historical context for understanding their current burden of heart disease, and provides important clues for understanding the determinants of the geographic disparities in heart disease mortality. © 2016 American Heart Association, Inc.

Developmental Change in Fetal Response to Repeated Low-Intensity Sound

ERIC Educational Resources Information Center

Morokuma, Seiichi; Doria, Valentina; Ierullo, Antonio; Kinukawa, Naoko; Fukushima, Kotaro; Nakano, Hitoo; Arulkumaran, Sabaratnam; Papageorghiou, Aris T.

2008-01-01

The aim of this study was to investigate developmental changes in heart rate response to repeated low-intensity (85 dB) sound stimulation in fetuses between 32 and 37 weeks of gestation. We measured amplitude changes in heart rate as our index of fetal response. At 35 to 37 weeks of gestation, the majority of fetuses showed a deceleratory response…

Pedi-cap color change precedes a significant increase in heart rate during neonatal resuscitation.

PubMed

Blank, Doug; Rich, Wade; Leone, Tina; Garey, Donna; Finer, Neil

2014-11-01

Heart rate is the most important indicator of infant well-being during neonatal resuscitation. The Nellcor Pedi-Cap turns gold when exposed to exhaled gas with CO₂>15 mmHg. The aim of this study was to determine if Pedi-Cap gold color change during neonatal resuscitation precedes an increase in heart rate in babies with bradycardia receiving mask ventilation. This was a single-center retrospective review of video recordings and physiologic data of newborns with bradycardia receiving mask positive pressure ventilation during neonatal resuscitation. Subjects were included if the baby's HR<100 BPM within the first 90 s of resuscitation. The primary outcome was the change in HR prior to Pedi-Cap gold color change compared to the HR after Pedi-Cap gold color change. Forty-one newborns during the study period had HR<100 BPM and received mask positive pressure ventilation with a Pedi-Cap. The median heart rate 10s prior to Pedi-Cap gold color change was 75 BPM (IQR 62-85) and increased to 136 BPM (IQR 113-158) 30 s after gold color change (p<0.001). SpO₂ increased from 45 ± 17% prior to Pedi-Cap gold color change to 52 ± 17% 30s after gold color change (p=0.001). Colorimetric CO₂ detection during mask positive pressure ventilation in neonatal resuscitation precedes a significant increase in heart rate and SpO₂. The Pedi-Cap can be easily applied during resuscitation, requires no electricity, provides immediate feedback and may be a useful, simple tool early in resuscitation and may be especially useful in resource limited settings. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Pharmacological heart rate lowering in patients with a preserved ejection fraction-review of a failing concept.

PubMed

Meyer, Markus; Rambod, Mehdi; LeWinter, Martin

2018-07-01

Epidemiological studies have demonstrated that high resting heart rates are associated with increased mortality. Clinical studies in patients with heart failure and reduced ejection fraction have shown that heart rate lowering with beta-blockers and ivabradine improves survival. It is therefore often assumed that heart rate lowering is beneficial in other patients as well. Here, we critically appraise the effects of pharmacological heart rate lowering in patients with both normal and reduced ejection fraction with an emphasis on the effects of pharmacological heart rate lowering in hypertension and heart failure. Emerging evidence from recent clinical trials and meta-analyses suggest that pharmacological heart rate lowering is not beneficial in patients with a normal or preserved ejection fraction. This has just begun to be reflected in some but not all guideline recommendations. The detrimental effects of pharmacological heart rate lowering are due to an increase in central blood pressures, higher left ventricular systolic and diastolic pressures, and increased ventricular wall stress. Therefore, we propose that heart rate lowering per se reproduces the hemodynamic effects of diastolic dysfunction and imposes an increased arterial load on the left ventricle, which combine to increase the risk of heart failure and atrial fibrillation. Pharmacologic heart rate lowering is clearly beneficial in patients with a dilated cardiomyopathy but not in patients with normal chamber dimensions and normal systolic function. These conflicting effects can be explained based on a model that considers the hemodynamic and ventricular structural effects of heart rate changes.

Measuring high pressure baroreceptor sensitivity in the rat.

PubMed

Shiry, L J; Hamlin, R L

2011-01-01

The high pressure baroreceptor reflex rapidly buffers changes in systemic arterial pressure in response to postural changes, altered gravitational conditions, diseases, and pharmacological agents. Drug-induced exaggeration of changes in heart rate and in systemic arterial pressure is a leading cause of adverse events and of patients terminating use of drugs, particularly in the aging population. This paper presents a facile method for monitoring the high pressure baroreceptor reflex in rats, and presents an alternative to quantifying the magnitude of this reflex using 2 dependent variables, heart rate and systemic arterial pressure, rather than merely change in heart rate. Twenty-four rats were allocated to 3 groups: group I anesthetized with 100mg/kg thiopental, group II anesthetized with 2% isoflurane given by inhalation, group III anesthetized with thiopental but pretreated for 2weeks with 2μg/kg aldosterone given SQ bid. After induction to anesthesia, hair was clipped from the ventral aspect of the neck, and petrolatum was applied to the skin to permit an air-tight seal with a glass funnel attached to a source of variable and controllable negative pressure. Systemic arterial pressure, ECG, heart rate, and a force of suction applied to the neck were all recorded continuously. After baseline recordings, a force of -20mmHg was applied for 20s over the carotid artery. In rats receiving thiopental, the average changes in heart rate and systemic arterial pressure following the application of -20mmHg neck suction were 30±11bpm and 45±14mmHg, respectively. The ratios of change in heart and change in systemic arterial pressure to application of negative force over the carotid sinus are 1.5±0.6bpm/mmHg and 0.7±04mmHg/mmHg, respectively. Mean values for heart rate and for mean systemic arterial pressure during baseline and after application of neck suction for 20s showed little to no decrease (i.e., blunting) in rats anesthetized with isoflurane or pretreated with aldosterone. Thus this methodology was able to detect, in rats, blunting of baroreceptor function for at least 2 perturbations of this important homeostatic control system. Copyright © 2011. Published by Elsevier Inc.

An open-source LabVIEW application toolkit for phasic heart rate analysis in psychophysiological research.

PubMed

Duley, Aaron R; Janelle, Christopher M; Coombes, Stephen A

2004-11-01

The cardiovascular system has been extensively measured in a variety of research and clinical domains. Despite technological and methodological advances in cardiovascular science, the analysis and evaluation of phasic changes in heart rate persists as a way to assess numerous psychological concomitants. Some researchers, however, have pointed to constraints on data analysis when evaluating cardiac activity indexed by heart rate or heart period. Thus, an off-line application toolkit for heart rate analysis is presented. The program, written with National Instruments' LabVIEW, incorporates a variety of tools for off-line extraction and analysis of heart rate data. Current methods and issues concerning heart rate analysis are highlighted, and how the toolkit provides a flexible environment to ameliorate common problems that typically lead to trial rejection is discussed. Source code for this program may be downloaded from the Psychonomic Society Web archive at www.psychonomic.org/archive/.

Stochastic optimization for the detection of changes in maternal heart rate kinetics during pregnancy

NASA Astrophysics Data System (ADS)

Zakynthinaki, M. S.; Barakat, R. O.; Cordente Martínez, C. A.; Sampedro Molinuevo, J.

2011-03-01

The stochastic optimization method ALOPEX IV has been successfully applied to the problem of detecting possible changes in the maternal heart rate kinetics during pregnancy. For this reason, maternal heart rate data were recorded before, during and after gestation, during sessions of exercises of constant mild intensity; ALOPEX IV stochastic optimization was used to calculate the parameter values that optimally fit a dynamical systems model to the experimental data. The results not only demonstrate the effectiveness of ALOPEX IV stochastic optimization, but also have important implications in the area of exercise physiology, as they reveal important changes in the maternal cardiovascular dynamics, as a result of pregnancy.

Effects of subchronic exposures to concentrated ambient particles (CAPs) in mice. III. Acute and chronic effects of CAPs on heart rate, heart-rate fluctuation, and body temperature.

PubMed

Hwang, Jing-Shiang; Nadziejko, Christine; Chen, Lung Chi

2005-04-01

Normal mice (C57) and mice prone to develop atherosclerosis (ApoE-/-) were implanted with electrocardiograph (EKG), core body temperature, and motion transmitters were exposed daily for 6 h to Tuxedo, NY, concentrated ambient particles (CAPs) for 5 day/wk during the spring and summer of 2003. The series of 5-min EKG monitoring and body-temperature measurements were obtained for each animal in the CAPs and filtered air sham exposure groups. Our hypothesis was that chronic exposure could cause cumulative health effects. We used our recently developed nonparametric method to estimate the daily time periods that mean heart rates (HR), body temperature, and physical activity differed significantly between the CAPs and sham exposed group. CAPs exposure most affected heart rate between 1:30 a.m. and 4:30 a.m. With the response variables being the average heart rate, body temperature, and physical activity, we adopted a two-stage modeling approach to obtain the estimates of chronic and acute effects on the changes of these three response variables. In the first stage, a time-varying model estimated daily crude effects. In the second stage, the true means of the estimated crude effects were modeled with a polynominal function of time for chronic effects, a linear term of daily CAPs exposure concentrations for acute effects, and a random component for unknown noise. A Bayesian framework combined these two stages. There were significant decreasing patterns of HR, body temperature, and physical activity for the ApoE-/- mice over the 5 mo of CAPs exposure, with smaller and nonsignificant changes for the C57 mice. The chronic effect changes of the three response variables for ApoE-/- mice were maximal in the last few weeks. There was also a significant relationship between CAPs exposure concentration and short-term changes of heart rate in ApoE-/- mice during exposure. Response variables were also defined for examining fluctuations of 5-min heart rates within long (i.e., 3-6 h) and short time periods (i.e., approximately 15 min). The results for the ApoE-/- mice showed that heart-rate fluctuation within the longer periods increased to 1.35-fold by the end of exposure experiment, while the heart-rate fluctuation within 15 min decreased to 0.7-fold.

Slow Heartbeat

MedlinePlus

... Back to Symptoms & Diagnosis Slow Heartbeat Slow heartbeat (heart rate), called bradycardia , is an arrhythmia , or disorder of ... 60 to 100 times a minute. Changes in heart rate caused by activity, diet, medications, and age are ...

Probability of detection of clinical seizures using heart rate changes.

PubMed

Osorio, Ivan; Manly, B F J

2015-08-01

Heart rate-based seizure detection is a viable complement or alternative to ECoG/EEG. This study investigates the role of various biological factors on the probability of clinical seizure detection using heart rate. Regression models were applied to 266 clinical seizures recorded from 72 subjects to investigate if factors such as age, gender, years with epilepsy, etiology, seizure site origin, seizure class, and data collection centers, among others, shape the probability of EKG-based seizure detection. Clinical seizure detection probability based on heart rate changes, is significantly (p<0.001) shaped by patients' age and gender, seizure class, and years with epilepsy. The probability of detecting clinical seizures (>0.8 in the majority of subjects) using heart rate is highest for complex partial seizures, increases with a patient's years with epilepsy, is lower for females than for males and is unrelated to the side of hemisphere origin. Clinical seizure detection probability using heart rate is multi-factorially dependent and sufficiently high (>0.8) in most cases to be clinically useful. Knowledge of the role that these factors play in shaping said probability will enhance its applicability and usefulness. Heart rate is a reliable and practical signal for extra-cerebral detection of clinical seizures originating from or spreading to central autonomic network structures. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

[Changes in heart rate variability after myocardial infarction. Value of Poincareé's diagram].

PubMed

Copie, X; Le Heuzey, J Y; Iliou, M C; Pousset, F; Lavergne, T; Guize, L

1995-11-01

The variability of the heart rate is reduced after myocardial infarction. It then progressively increases, to return to near normal values after several months. However, these changes in heart rate variability occur at the same time as slowing of the heart rate which makes interpretation difficult. Poincaré's diagram is constructed from a Holter recording plotting each RR interval against the preceding RR interval. The authors have developed a geometric approach to this diagram to evaluate parasympathetic tone for a given heart rate. By measuring the dispersion in height of the Poincaré's diagram, the authors evaluate the shor-term variability for a given RR interval. Two 24 hr Holter recordings were performed in 52 patients at one and two weeks after a myocardial infarction. The dispersion in the height of the Poincaré's diagrams was measured at the 10th, 25th, 50th, 75th and 90th percentiles of the total dispersion. The authors have shown an increase in the short-term variability of the shortest RR intervals (1th, 25th and 50th percentiles) which is not observed in the longer RR intervals (75th and 90th percentiles). In conclusion, theres is an increase in the heart rate variability at the shortest RR intervals. This suggests that the recovery of parasympathic tone after myocardial infarction occurs mainly at the fastest heart rates.

Changes in the Geographic Patterns of Heart Disease Mortality in the United States

PubMed Central

Casper, Michele; Kramer, Michael R.; Quick, Harrison; Schieb, Linda J.; Vaughan, Adam S.; Greer, Sophia

2016-01-01

Background Although many studies have documented the dramatic declines in heart disease mortality in the United States at the national level, little attention has been given to the temporal changes in the geographic patterns of heart disease mortality. Methods and Results Age-adjusted and spatially smoothed county-level heart disease death rates were calculated for 2-year intervals from 1973 to 1974 to 2009 to 2010 for those aged ≥35 years. Heart disease deaths were defined according to the International Classification of Diseases codes for diseases of the heart in the eighth, ninth, and tenth revisions of the International Classification of Diseases. A fully Bayesian spatiotemporal model was used to produce precise rate estimates, even in counties with small populations. A substantial shift in the concentration of high-rate counties from the Northeast to the Deep South was observed, along with a concentration of slow-decline counties in the South and a nearly 2-fold increase in the geographic inequality among counties. Conclusions The dramatic change in the geographic patterns of heart disease mortality during 40 years highlights the importance of small-area surveillance to reveal patterns that are hidden at the national level, gives communities the historical context for understanding their current burden of heart disease, and provides important clues for understanding the determinants of the geographic disparities in heart disease mortality. PMID:27002081

Crew workload in JASDF C-1 transport flights: I. Change in heart rate and salivary cortisol.

PubMed

Kakimoto, Y; Nakamura, A; Tarui, H; Nagasawa, Y; Yagura, S

1988-06-01

The physiological responses of heart rate and salivary cortisol for six paired captains and co-pilots during JASDF scheduled transport flights were compared to assess crew workload. The relative change of both responses showed similar patterns and were influenced significantly by whether pilots were controlling the aircraft. Moreover, differences in flying experience and responsibility of captains and co-pilots influenced the two physiological responses; heart rate and salivary cortisol measures increased more for both captains and co-pilots while they were in control of the aircraft than when they were not. Compared to captains, co-pilots showed much higher activation and variability in relative change of heart rate and salivary cortisol between periods of controlling and non-controlling the aircraft. On the other hand, captains showed relatively constant responses comparing aircraft controlling and non-controlling periods, especially in the cruise phase of flight. Salivary cortisol may be a useful, non-invasive method of assess crew workload.

Reassessment of the cardio-respiratory stress response, using the king penguin as a model.

PubMed

Willener, Astrid S T; Halsey, Lewis G; Strike, Siobhán; Enstipp, Manfred R; Georges, Jean-Yves; Handrich, Yves

2015-01-01

Research in to short-term cardio-respiratory changes in animals in reaction to a psychological stressor typically describes increases in rate of oxygen consumption (V̇(O2)) and heart rate. Consequently, the broad consensus is that they represent a fundamental stressor response generalizable across adult species. However, movement levels can also change in the presence of a stressor, yet studies have not accounted for this possible confound on heart rate. Thus the direct effects of psychological stressors on the cardio-respiratory system are not resolved. We used an innovative experimental design employing accelerometers attached to king penguins (Aptenodytes patagonicus) to measure and thus account for movement levels in a sedentary yet free-to-move animal model during a repeated measures stress experiment. As with previous studies on other species, incubating king penguins (N = 6) exhibited significant increases in both V̇(O2) and heart rate when exposed to the stressor. However, movement levels, while still low, also increased in response to the stressor. Once this was accounted for by comparing periods of time during the control and stress conditions when movement levels were similar as recorded by the accelerometers, only V̇(O2) significantly increased; there was no change in heart rate. These findings offer evidence that changing movement levels have an important effect on the measured stress response and that the cardio-respiratory response per se to a psychological stressor (i.e. the response as a result of physiological changes directly attributable to the stressor) is an increase in V̇(O2) without an increase in heart rate.

Relationship Between Kinematic and Physiological Indices During Braking Events of Different Intensities.

PubMed

Musicant, Oren; Botzer, Assaf; Laufer, Ilan; Collet, Christian

2018-05-01

Objective To study the relationship between physiological indices and kinematic indices during braking events of different intensities. Background Based on mental workload theory, driving and other task demands may generate changes in physiological indices, such as the driver's heart rate and skin conductance. However, no attempts were made to associate changes in physiological indices with changes in vehicle kinematics that result from the driver attempts to meet task demands. Method Twenty-five drivers participated in a field experiment. We manipulated braking demands using roadside signs to communicate the speed (km/h) before braking (50 or 60) and the target speed for braking (30 or to a complete stop). In an additional session, we asked drivers to brake as if they were responding to an impending collision. We analyzed the relationship between the intensities of braking events as measured by deceleration values (g) and changes in heart rate, heart rate variability, and skin conductance. Results All physiological indices were associated with deceleration intensity. Especially salient were the differences in physiological indices between the intensive (|g| > 0.5) and nonintensive braking events. The strongest relationship was between braking intensity and skin conductance. Conclusions Skin conductance, heart rate, and heart rate variability can mirror the mental workload elicited by varying braking intensities. Application Associating vehicle kinematics with physiological indices related to short-term driving events may help improve the performance of driver assistance systems.

Vagal Nerve Stimulation Evoked Heart Rate Changes and Protection from Cardiac Remodeling.

PubMed

Agarwal, Rahul; Mokelke, Eric; Ruble, Stephen B; Stolen, Craig M

2016-02-01

This study investigated whether vagal nerve stimulation (VNS) leads to improvements in ischemic heart failure via heart rate modulation. At 7 ± 1 days post left anterior descending artery (LAD) ligation, 63 rats with myocardial infarctions (MI) were implanted with ECG transmitters and VNS devices (MI + VNS, N = 44) or just ECG transmitters (MI, N = 17). VNS stimulation was active from 14 ± 1 days to 8 ± 1 weeks post MI. The average left ventricular (LV) end diastolic volumes at 8 ± 1 weeks were MI = 672.40 μl and MI + VNS = 519.35 μl, p = 0.03. The average heart weights, normalized to body weight (± std) at 14 ± 1 weeks were MI = 3.2 ± 0.6 g*kg(-1) and MI + VNS = 2.9 ± 0.3 g*kg(-1), p = 0.03. The degree of cardiac remodeling was correlated with the magnitude of acute VNS-evoked heart rate (HR) changes. Further research is required to determine if the acute heart rate response to VNS activation is useful as a heart failure biomarker or as a tool for VNS therapy characterization.

Factors Influencing the Cardiovascular Response to Subanesthetic Ketamine: A Randomized, Placebo-Controlled Trial

PubMed Central

Li, Shijia; Lord, Anton; Colic, Lejla; Krause, Anna Linda; Batra, Anil; Kretzschmar, Moritz A; Sweeney-Reed, Catherine M; Behnisch, Gusalija; Schott, Björn H; Walter, Martin

2017-01-01

Abstract Background The increasing use of ketamine as a potential rapid-onset antidepressant necessitates a better understanding of its effects on blood pressure and heart rate, well-known side effects at higher doses. For the subanesthetic dose used for depression, potential predictors of these cardiovascular effects are important factors influencing clinical decisions. Since ketamine influences the sympathetic nervous system, we investigated the impact of autonomic nervous system-related factors on the cardiovascular response: a genetic polymorphism in the norepinephrine transporter and gender effects. Methods Blood pressure and heart rate were monitored during and following administration of a subanesthetic dose of ketamine or placebo in 68 healthy participants (mean age 26.04 ±5.562 years) in a double-blind, randomized, controlled, parallel-design trial. The influences of baseline blood pressure/heart rate, gender, and of a polymorphism in the norepinephrine transporter gene (NET SLC6A2, rs28386840 [A-3081T]) on blood pressure and heart rate changes were investigated. To quantify changes in blood pressure and heart rate, we calculated the maximum change from baseline (ΔMAX) and the time until maximum change (TΔMAX). Results Systolic and diastolic blood pressure as well as heart rate increased significantly upon ketamine administration, but without reaching hypertensive levels. During administration, the systolic blood pressure at baseline (TP0Sys) correlated negatively with the time to achieve maximal systolic blood pressure (TΔMAXSys, P<.001). Furthermore, women showed higher maximal diastolic blood pressure change (ΔMAXDia, P<.001) and reached this peak earlier than men (TΔMAXDia, P=.017) at administration. NET rs28386840 [T] carriers reached their maximal systolic blood pressure during ketamine administration significantly earlier than [A] homozygous (TΔMAXSys, P=.030). In a combined regression model, both genetic polymorphism and TP0Sys were significant predictors of TΔMAXSys (P<.0005). Conclusions Subanesthetic ketamine increased both blood pressure and heart rate without causing hypertensive events. Furthermore, we identified gender and NET rs28386840 genotype as factors that predict increased cardiovascular sequelae of ketamine administration in our young, healthy study population providing a potential basis for establishing monitoring guidelines. PMID:29099972

Control of heart rate during thermoregulation in the heliothermic lizard Pogona barbata: importance of cholinergic and adrenergic mechanisms.

PubMed

Seebacher, F; Franklin, C E

2001-12-01

During thermoregulation in the bearded dragon Pogona barbata, heart rate when heating is significantly faster than when cooling at any given body temperature (heart rate hysteresis), resulting in faster rates of heating than cooling. However, the mechanisms that control heart rate during heating and cooling are unknown. The aim of this study was to test the hypothesis that changes in cholinergic and adrenergic tone on the heart are responsible for the heart rate hysteresis during heating and cooling in P. barbata. Heating and cooling trials were conducted before and after the administration of atropine, a muscarinic antagonist, and sotalol, a beta-adrenergic antagonist. Cholinergic and beta-adrenergic blockade did not abolish the heart rate hysteresis, as the heart rate during heating was significantly faster than during cooling in all cases. Adrenergic tone was extremely high (92.3 %) at the commencement of heating, and decreased to 30.7 % at the end of the cooling period. Moreover, in four lizards there was an instantaneous drop in heart rate (up to 15 beats min(-1)) as the heat source was switched off, and this drop in heart rate coincided with either a drop in beta-adrenergic tone or an increase in cholinergic tone. Rates of heating were significantly faster during the cholinergic blockade, and least with a combined cholinergic and beta-adrenergic blockade. The results showed that cholinergic and beta-adrenergic systems are not the only control mechanisms acting on the heart during heating and cooling, but they do have a significant effect on heart rate and on rates of heating and cooling.

A systematic review of prenatal screening for congenital heart disease by fetal electrocardiography.

PubMed

Verdurmen, Kim M J; Eijsvoogel, Noortje B; Lempersz, Carlijn; Vullings, Rik; Schroer, Christian; van Laar, Judith O E H; Oei, S Guid

2016-11-01

Congenital heart disease (CHD) is the most common severe congenital anomaly worldwide. Diagnosis early in pregnancy is important, but the detection rate by two-dimensional ultrasonography is only 65%-81%. To evaluate existing data on CHD and noninvasive abdominal fetal electrocardiography (ECG). A systematic review was performed through a search of the Cochrane Library, PubMed, and Embase for studies published up to April 2016 using the terms "congenital heart disease," "fetal electrocardiogram," and other similar keywords. Primary articles that described changes in fetal ECG among fetuses with CHD published in English were included. Outcomes of interest were changes in fetal ECG parameters observed for fetuses with congenital heart disease. Findings were reported descriptively. Only five studies described changes observed in the fetal electrocardiogram for fetuses with CHD, including heart rate, heart rate variability, and PR, QRS, and QT intervals. Fetal ECG reflects the intimate relationship between the cardiac nerve conduction system and the structural morphology of the heart. It seems particularly helpful in detecting the electrophysiological effects of cardiac anatomic defects (e.g. hypotrophy, hypertrophy, and conduction interruption). Fetal ECG might be a promising clinical tool to complement ultrasonography in the screening program for CHD. Copyright © 2016 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

The effect of talking about psychological trauma with a significant other on heart rate reactivity in individuals with posttraumatic stress disorder.

PubMed

Nachar, Nadim; Lavoie, Marc E; Marchand, André; O'Connor, Kieron P; Guay, Stéphane

2014-09-30

Individuals with posttraumatic stress disorder (PTSD) commonly make efforts to avoid trauma-oriented conversations with their significant others, which may interfere with the natural recovery process. Trauma-oriented conversations can be experienced as physiologically arousing, depending on the intensity of PTSD symptoms and perceptions of social support. In the current investigation, changes in heart rate responses to a trauma-oriented social interaction with a significant other were assessed. Perceived supportive and unsupportive or negative social interactions were examined as moderators of the association between heart rate changes to this context and intensity of PTSD symptoms. A total of 46 individuals with PTSD completed diagnostic interviews and self-report measures of symptoms and perceived supportive and negative social interactions during a trauma-oriented social interaction with a significant other. Heart rate was continuously measured during this interaction. Results showed that engagement in a trauma-oriented social interaction was predictive of elevations in heart rate that positively correlated with intensity of PTSD symptoms. The moderation hypothesis was partially supported. In addition, perceived negative social interactions positively correlated with elevations in heart rate. These findings can inform social intervention efforts for individuals with PTSD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Heart rate-induced modifications of concentric left ventricular hypertrophy: exploration of a novel therapeutic concept.

PubMed

Klein, Franziska J; Bell, Stephen; Runte, K Elisabeth; Lobel, Robert; Ashikaga, Takamuru; Lerman, Lilach O; LeWinter, Martin M; Meyer, Markus

2016-10-01

Lowering the heart rate is considered to be beneficial in heart failure (HF) with reduced ejection fraction (HFrEF). In a dilated left ventricle (LV), pharmacological heart rate lowering is associated with a reduction in LV chamber size. In patients with HFrEF, this structural change is associated with better survival. HF with preserved ejection fraction (HFpEF) is increasingly prevalent but, so far, without any evidence-based treatment. HFpEF is typically associated with LV concentric remodeling and hypertrophy. The effects of heart rate on this structural phenotype are not known. Analogous with the benefits of a low heart rate on a dilated heart, we hypothesized that increased heart rates could lead to potentially beneficial remodeling of a concentrically hypertrophied LV. This was explored in an established porcine model of concentric LV hypertrophy and fibrosis. Our results suggest that a moderate increase in heart rate can be used to reduce wall thickness, normalize LV chamber volumes, decrease myocardial fibrosis, and improve LV compliance. Our results also indicate that the effects of heart rate can be titrated, are reversible, and do not induce HF. These findings may provide the rationale for a novel therapeutic approach for HFpEF and its antecedent disease substrate. Copyright © 2016 the American Physiological Society.

Variability in heart rate recovery measurements over 1 year in healthy, middle-aged adults.

PubMed

Mellis, M G; Ingle, L; Carroll, S

2014-02-01

This study assessed the longer-term (12-month) variability in post-exercise heart rate recovery following a submaximal exercise test. Longitudinal data was analysed for 97 healthy middle-aged adults (74 male, 23 female) from 2 occasions, 12 months apart. Participants were retrospectively selected if they had stable physical activity habits, submaximal treadmill fitness and anthropometric measurements between the 2 assessment visits. A submaximal Bruce treadmill test was performed to at least 85% age-predicted maximum heart rate. Absolute heart rate and Δ heart rate recovery (change from peak exercise heart rate) were recorded for 1 and 2 min post-exercise in an immediate supine position. Heart rate recovery at both time-points was shown to be reliable with intra-class correlation coefficient values ≥ 0.714. Absolute heart rate 1-min post-exercise showed the strongest agreement between repeat tests (r = 0.867, P < 0.001). Lower coefficient of variation (≤ 10.2%) and narrower limits of agreement were found for actual heart rate values rather than Δ heart rate recovery, and for 1-min rather than 2-min post-exercise recovery time points. Log-transformed values generated better variability with acceptable coefficient of variation for all measures (2.2-10%). Overall, 1 min post-exercise heart rate recovery data had least variability over the 12-month period in apparently healthy middle-aged adults. © Georg Thieme Verlag KG Stuttgart · New York.

Heart rate variability in patients with systemic lupus erythematosus: a systematic review and methodological considerations.

PubMed

Matusik, P S; Matusik, P T; Stein, P K

2018-07-01

Aim The aim of this review was to summarize current knowledge about the scientific findings and potential clinical utility of heart rate variability measures in patients with systemic lupus erythematosus. Methods PubMed, Embase and Scopus databases were searched for the terms associated with systemic lupus erythematosus and heart rate variability, including controlled vocabulary, when appropriate. Articles published in English and available in full text were considered. Finally, 11 publications were selected, according to the systematic review protocol and were analyzed. Results In general, heart rate variability, measured in the time and frequency domains, was reported to be decreased in patients with systemic lupus erythematosus compared with controls. In some systemic lupus erythematosus studies, heart rate variability was found to correlate with inflammatory markers and albumin levels. A novel heart rate variability measure, heart rate turbulence onset, was shown to be increased, while heart rate turbulence slope was decreased in systemic lupus erythematosus patients. Reports of associations of changes in heart rate variability parameters with increasing systemic lupus erythematosus activity were inconsistent, showing decreasing heart rate variability or no relationship. However, the low/high frequency ratio was, in some studies, reported to increase with increasing disease activity or to be inversely correlated with albumin levels. Conclusions Patients with systemic lupus erythematosus have abnormal heart rate variability, which reflects cardiac autonomic dysfunction and may be related to inflammatory cytokines but not necessarily to disease activity. Thus measurement of heart rate variability could be a useful clinical tool for monitoring autonomic dysfunction in systemic lupus erythematosus, and may potentially provide prognostic information.

Modulations of Heart Rate, ECG, and Cardio-Respiratory Coupling Observed in Polysomnography

PubMed Central

Penzel, Thomas; Kantelhardt, Jan W.; Bartsch, Ronny P.; Riedl, Maik; Kraemer, Jan F.; Wessel, Niels; Garcia, Carmen; Glos, Martin; Fietze, Ingo; Schöbel, Christoph

2016-01-01

The cardiac component of cardio-respiratory polysomnography is covered by ECG and heart rate recordings. However, their evaluation is often underrepresented in summarizing reports. As complements to EEG, EOG, and EMG, these signals provide diagnostic information for autonomic nervous activity during sleep. This review presents major methodological developments in sleep research regarding heart rate, ECG, and cardio-respiratory couplings in a chronological (historical) sequence. It presents physiological and pathophysiological insights related to sleep medicine obtained by new technical developments. Recorded nocturnal ECG facilitates conventional heart rate variability (HRV) analysis, studies of cyclical variations of heart rate, and analysis of ECG waveform. In healthy adults, the autonomous nervous system is regulated in totally different ways during wakefulness, slow-wave sleep, and REM sleep. Analysis of beat-to-beat heart-rate variations with statistical methods enables us to estimate sleep stages based on the differences in autonomic nervous system regulation. Furthermore, up to some degree, it is possible to track transitions from wakefulness to sleep by analysis of heart-rate variations. ECG and heart rate analysis allow assessment of selected sleep disorders as well. Sleep disordered breathing can be detected reliably by studying cyclical variation of heart rate combined with respiration-modulated changes in ECG morphology (amplitude of R wave and T wave). PMID:27826247

Modulations of Heart Rate, ECG, and Cardio-Respiratory Coupling Observed in Polysomnography.

PubMed

Penzel, Thomas; Kantelhardt, Jan W; Bartsch, Ronny P; Riedl, Maik; Kraemer, Jan F; Wessel, Niels; Garcia, Carmen; Glos, Martin; Fietze, Ingo; Schöbel, Christoph

2016-01-01

The cardiac component of cardio-respiratory polysomnography is covered by ECG and heart rate recordings. However, their evaluation is often underrepresented in summarizing reports. As complements to EEG, EOG, and EMG, these signals provide diagnostic information for autonomic nervous activity during sleep. This review presents major methodological developments in sleep research regarding heart rate, ECG, and cardio-respiratory couplings in a chronological (historical) sequence. It presents physiological and pathophysiological insights related to sleep medicine obtained by new technical developments. Recorded nocturnal ECG facilitates conventional heart rate variability (HRV) analysis, studies of cyclical variations of heart rate, and analysis of ECG waveform. In healthy adults, the autonomous nervous system is regulated in totally different ways during wakefulness, slow-wave sleep, and REM sleep. Analysis of beat-to-beat heart-rate variations with statistical methods enables us to estimate sleep stages based on the differences in autonomic nervous system regulation. Furthermore, up to some degree, it is possible to track transitions from wakefulness to sleep by analysis of heart-rate variations. ECG and heart rate analysis allow assessment of selected sleep disorders as well. Sleep disordered breathing can be detected reliably by studying cyclical variation of heart rate combined with respiration-modulated changes in ECG morphology (amplitude of R wave and T wave).

Power spectral analysis of R-R interval variability before and during the sinusoidal heart rate pattern in fetal lambs.

PubMed

Suzuki, T; Okamura, K; Kimura, Y; Watanabe, T; Yaegashi, N; Murotsuki, J; Uehara, S; Yajima, A

2000-05-01

The appearance of the sinusoidal heart rate pattern found on fetal cardiotocograms has not been fully explained, either physiologically or clinically. In this study we performed power spectral analysis on the sinusoidal heart rate pattern obtained by administration of arginine vasopressin and atropine sulfate to investigate its frequency components in fetal lambs with long-term instrument implantation. Eleven tests were performed in 4 fetal lambs at 120 to 130 days' gestation. An artificial sinusoidal heart rate pattern was obtained by administration of atropine sulfate and arginine vasopressin in 9 tests. An autoregression model was used to compare the spectral patterns before and during the sinusoidal heart rate pattern. Marked decreases in low-frequency (0.025-0.125 cycles/beat) and high-frequency (0.2-0.5 cycles/beat) areas were observed in the presence of the sinusoidal heart rate pattern. However, there were no significant changes in the very-low-frequency area (0.01-0.025 cycles/beat), which corresponds to the frequency of the sinusoidal heart rate pattern. The sinusoidal heart rate pattern may represent a very low-frequency component inherent in fetal heart rate variability that appears when low- and high-frequency components are reduced as a result of strongly suppressed autonomic nervous activity.

Characteristics of cardio-Cerebrovascular modulation in patients with generalized anxiety disorder: an observational study.

PubMed

Guo, Zhen-Ni; Feng, Liangshu; Yan, Xiuli; Yang, Le; Huang, Shuo; Xing, Yingqi; Yang, Yi

2017-07-18

Generalized anxiety disorder (GAD) has been shown in previous studies to display abnormal cerebral blood flow velocity (CBFV); however, the characteristics of cardio-cerebrovascular modulation are unknown. We aimed to analyze cardio-cerebrovascular modulation using parameters from a supine-to-standing test. There are 2 parts to this study; in Part 1, 125 participants with Hamilton Anxiety scale scores ≥14 were enrolled, and 33 age- and sex-matched medically and psychiatrically healthy volunteers were recruited as control participants. Patients were divided by score into mild, moderate, and severe anxiety groups. The cardio-cerebrovascular modulation using the parameters of dynamic changes of CBFV and heart rate in response to an orthostatic challenge were investigated. In Part 2, we followed up the severe GAD patients for 6 months and repeated the supine-to-standing test, and severe GAD patients were divided into recovery and non-recovery groups. In part 1, the GAD group displayed more marked CBFV and heart rate changes than the healthy group, but there was no difference in the CBFV and heart rate changes from the supine to upright position in mild, moderate, and severe anxiety groups. In part 2, The recovery group demonstrated significant improvement in changes in the CBFV and heart rate values from the supine to the upright position after treatment compared with before treatment. In the non-recovery group, the CBFV and heart rate changes were significantly higher than the healthy group regardless of treatment. Cardio-cerebrovascular modulation is compromised in patients with GAD, however, this impairment can be restored to normal after the disappearance of anxiety.

Simultaneous assessment of autonomic function and anxiety-related behavior in BALB/c and C57BL/6 mice.

PubMed

Depino, Amaicha Mara; Gross, Cornelius

2007-02-27

In humans, anxiety is accompanied by changes in autonomic nervous system function, including increased heart rate, body temperature, and blood pressure, and decreased heart rate variability. In rodents, anxiety is inferred by examining anxiety-related behavioral responses such as avoidance and freezing, and more infrequently by assessing autonomic responses to anxiogenic stimuli. However, few studies have simultaneously measured behavioral and autonomic responses to aversive stimuli in rodents and it remains unclear whether autonomic measures are reliable correlates of anxiety-related behavior in these animal models. Here we recorded for the first time heart rate and body temperature in freely moving BALB/c and C57BL/6 mice during exposure to an unfamiliar environment. Our data show that upon exposure to a novel open field, BALB/c mice showed increased anxiety-related behavior, reduced heart rate and higher heart rate variability (HRV) when compared with C57BL/6 mice. Regression analysis revealed a significant correlation between both heart rate and long-term HRV measures and locomotor activity and time spent in the center of the open field, but no correlation between body temperature and any behavioral variables. In the free exploration test, in which animals were allowed direct access to a novel environment from a familiar environment without experimenter handling, significant correlations were found only between heart rate and total locomotor activity, but not time spent in the unfamiliar chamber despite increased anxiety-related behavior in BALB/c mice. These findings demonstrate that increased anxiety-related behavior in BALB/c mice is not associated with specific changes in heart rate, HRV, or body temperature.

Minimal changes in heart rate of incubating American Oystercatchers (Haematopus palliatus) in response to human activity

USGS Publications Warehouse

Borneman, Tracy E.; Rose, Eli T.; Simons, Theodore R.

2014-01-01

An organism's heart rate is commonly used as an indicator of physiological stress due to environmental stimuli. We used heart rate to monitor the physiological response of American Oystercatchers (Haematopus palliatus) to human activity in their nesting environment. We placed artificial eggs with embedded microphones in 42 oystercatcher nests to record the heart rate of incubating oystercatchers continuously for up to 27 days. We used continuous video and audio recordings collected simultaneously at the nests to relate physiological response of birds (heart rate) to various types of human activity. We observed military and civilian aircraft, off-road vehicles, and pedestrians around nests. With the exception of high-speed, low-altitude military overflights, we found little evidence that oystercatcher heart rates were influenced by most types of human activity. The low-altitude flights were the only human activity to significantly increase average heart rates of incubating oystercatchers (12% above baseline). Although statistically significant, we do not consider the increase in heart rate during high-speed, low-altitude military overflights to be of biological significance. This noninvasive technique may be appropriate for other studies of stress in nesting birds.

Influence of game format and number of players on heart rate responses and physical demands in small-sided soccer games.

PubMed

Castellano, Julen; Casamichana, David; Dellal, Alexandre

2013-05-01

The aim of the study was to examine the extent to which changing the game format (possession play vs. regulation goals and goalkeepers vs. small goals only) and the number of players (3 vs. 3, 5 vs. 5 and 7 vs. 7) influenced the physiological and physical demands of small-sided games (SSGs) in soccer in semiprofessional players. Fourteen semiprofessional male soccer players were monitored with global positioning system and heart rate devices. Heart rate, player load, distance covered, running speed, and the number of accelerations were recorded for 9 different SSGs. The results show that changes both in game format and the number of players affect the players' physiological and physical demands. Possession play places greater physiological and physical demands on players, although reducing the number of players only increases the physiological load. In the 7 vs. 7 games, changing the game format did not alter the heart rate responses. Finally, in the possession play format, changing the number of players did not produce significant differences in heart rate responses, although physical demands did decrease in line with a reduction in the number of players. These results should help coaches to understand how modifying different aspects of SSGs has a differential effect on the players' physiological and physical demands. Moreover, coaches in semiprofessional and amateur teams have now consistent information to design and optimize their training time in mixing the technical, tactical, and physical aspects.

iHeartLift: a closed loop system with bio-feedback that uses music tempo variability to improve heart rate variability.

PubMed

Ho, Thomas C T; Chen, Xiang

2011-01-01

"Musica delenit bestiam feram" translates into "Music soothes the savage beast". There is a hidden truth in this ancient quip passed down from generations. Besides soothing the heart, it also incites the heart to a healthier level of heart rate variability (HRV). In this paper, an approach to use and test music and biofeedback to increase the heart rate variability for people facing daily stress is discussed. By determining the music tempo variability (MTV) of a piece of music and current heart rate variability, iHeartLift is able to compare the 2 trends and locate a musical piece that is suited to increase the user's heart rate variability to a healthier level. With biofeedback, the 2 trends are continuously compared in real-time and the musical piece is changed in accordance with the current comparisons. A study was conducted and it was generally found that HRV can be uplifted by music regardless of language and meaning of musical lyrics but with limitations to musical genre.

Non-contact Real-time heart rate measurements based on high speed circuit technology research

NASA Astrophysics Data System (ADS)

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

2015-08-01

In recent years, morbidity and mortality of the cardiovascular or cerebrovascular disease, which threaten human health greatly, increased year by year. Heart rate is an important index of these diseases. To address this status, the paper puts forward a kind of simple structure, easy operation, suitable for large populations of daily monitoring non-contact heart rate measurement. In the method we use imaging equipment video sensitive areas. The changes of light intensity reflected through the image grayscale average. The light change is caused by changes in blood volume. We video the people face which include the sensitive areas (ROI), and use high-speed processing circuit to save the video as AVI format into memory. After processing the whole video of a period of time, we draw curve of each color channel with frame number as horizontal axis. Then get heart rate from the curve. We use independent component analysis (ICA) to restrain noise of sports interference, realized the accurate extraction of heart rate signal under the motion state. We design an algorithm, based on high-speed processing circuit, for face recognition and tracking to automatically get face region. We do grayscale average processing to the recognized image, get RGB three grayscale curves, and extract a clearer pulse wave curves through independent component analysis, and then we get the heart rate under the motion state. At last, by means of compare our system with Fingertip Pulse Oximeter, result show the system can realize a more accurate measurement, the error is less than 3 pats per minute.

Heart Rate Monitoring in Team Sports-A Conceptual Framework for Contextualizing Heart Rate Measures for Training and Recovery Prescription.

PubMed

Schneider, Christoph; Hanakam, Florian; Wiewelhove, Thimo; Döweling, Alexander; Kellmann, Michael; Meyer, Tim; Pfeiffer, Mark; Ferrauti, Alexander

2018-01-01

A comprehensive monitoring of fitness, fatigue, and performance is crucial for understanding an athlete's individual responses to training to optimize the scheduling of training and recovery strategies. Resting and exercise-related heart rate measures have received growing interest in recent decades and are considered potentially useful within multivariate response monitoring, as they provide non-invasive and time-efficient insights into the status of the autonomic nervous system (ANS) and aerobic fitness. In team sports, the practical implementation of athlete monitoring systems poses a particular challenge due to the complex and multidimensional structure of game demands and player and team performance, as well as logistic reasons, such as the typically large number of players and busy training and competition schedules. In this regard, exercise-related heart rate measures are likely the most applicable markers, as they can be routinely assessed during warm-ups using short (3-5 min) submaximal exercise protocols for an entire squad with common chest strap-based team monitoring devices. However, a comprehensive and meaningful monitoring of the training process requires the accurate separation of various types of responses, such as strain, recovery, and adaptation, which may all affect heart rate measures. Therefore, additional information on the training context (such as the training phase, training load, and intensity distribution) combined with multivariate analysis, which includes markers of (perceived) wellness and fatigue, should be considered when interpreting changes in heart rate indices. The aim of this article is to outline current limitations of heart rate monitoring, discuss methodological considerations of univariate and multivariate approaches, illustrate the influence of different analytical concepts on assessing meaningful changes in heart rate responses, and provide case examples for contextualizing heart rate measures using simple heuristics. To overcome current knowledge deficits and methodological inconsistencies, future investigations should systematically evaluate the validity and usefulness of the various approaches available to guide and improve the implementation of decision-support systems in (team) sports practice.

Heart Rate Monitoring in Team Sports—A Conceptual Framework for Contextualizing Heart Rate Measures for Training and Recovery Prescription

PubMed Central

Schneider, Christoph; Hanakam, Florian; Wiewelhove, Thimo; Döweling, Alexander; Kellmann, Michael; Meyer, Tim; Pfeiffer, Mark; Ferrauti, Alexander

2018-01-01

A comprehensive monitoring of fitness, fatigue, and performance is crucial for understanding an athlete's individual responses to training to optimize the scheduling of training and recovery strategies. Resting and exercise-related heart rate measures have received growing interest in recent decades and are considered potentially useful within multivariate response monitoring, as they provide non-invasive and time-efficient insights into the status of the autonomic nervous system (ANS) and aerobic fitness. In team sports, the practical implementation of athlete monitoring systems poses a particular challenge due to the complex and multidimensional structure of game demands and player and team performance, as well as logistic reasons, such as the typically large number of players and busy training and competition schedules. In this regard, exercise-related heart rate measures are likely the most applicable markers, as they can be routinely assessed during warm-ups using short (3–5 min) submaximal exercise protocols for an entire squad with common chest strap-based team monitoring devices. However, a comprehensive and meaningful monitoring of the training process requires the accurate separation of various types of responses, such as strain, recovery, and adaptation, which may all affect heart rate measures. Therefore, additional information on the training context (such as the training phase, training load, and intensity distribution) combined with multivariate analysis, which includes markers of (perceived) wellness and fatigue, should be considered when interpreting changes in heart rate indices. The aim of this article is to outline current limitations of heart rate monitoring, discuss methodological considerations of univariate and multivariate approaches, illustrate the influence of different analytical concepts on assessing meaningful changes in heart rate responses, and provide case examples for contextualizing heart rate measures using simple heuristics. To overcome current knowledge deficits and methodological inconsistencies, future investigations should systematically evaluate the validity and usefulness of the various approaches available to guide and improve the implementation of decision-support systems in (team) sports practice. PMID:29904351

Dynamic changes in scope for heart rate and cardiac autonomic control during warm acclimation in rainbow trout.

PubMed

Ekström, Andreas; Hellgren, Kim; Gräns, Albin; Pichaud, Nicolas; Sandblom, Erik

2016-04-15

Time course studies are critical for understanding regulatory mechanisms and temporal constraints in ectothermic animals acclimating to warmer temperatures. Therefore, we investigated the dynamics of heart rate and its neuro-humoral control in rainbow trout ( ITALIC! Onchorhynchus mykissL.) acclimating to 16°C for 39 days after being acutely warmed from 9°C. Resting heart rate was 39 beats min(-1)at 9°C, and increased significantly when fish were acutely warmed to 16°C ( ITALIC! Q10=1.9), but then declined during acclimation ( ITALIC! Q10=1.2 at day 39), mainly due to increased cholinergic inhibition while the intrinsic heart rate and adrenergic tone were little affected. Maximum heart rate also increased with warming, although a partial modest decrease occurred during the acclimation period. Consequently, heart rate scope exhibited a complex pattern with an initial increase with acute warming, followed by a steep decline and then a subsequent increase, which was primarily explained by cholinergic inhibition of resting heart rate. © 2016. Published by The Company of Biologists Ltd.

Clinical application of pulse transit time and correlation with intrapartum fetal heart rate monitoring: a preliminary study of 18 full-term infants.

PubMed

Kawagoe, Yasuyuki; Sameshima, Hiroshi; Ikenoue, Tsuyomu

2008-07-01

The authors show that pulse transit time and blood pressure are reciprocal in fetal goat models. They applied this technique in clinical settings to correlate changes in pulse transit time with fetal heart rate monitoring patterns and acid-base status. In 18 uncomplicated pregnancies, pulse transit time was obtained from electrocardiograms to pulse oximeter waveform and averaged during each baseline period, defined by the interpretation of fetal heart rate monitoring. According to a > 10% change from the control value, chronological changes were categorized into shortened, unchanged, and prolonged. Pulse transit time was available in 82% +/- 11% of the recordings. In 15 fetuses, 2 (13%) showed prolonged, 7 (47%) showed shortened, and 6 (40%) showed unchanged conditions. Comparisons of the shortened and unchanged categories revealed that severe variable deceleration was significantly increased, and half or more fetuses showed hypoxemia in the shortened category. Shortening of pulse transit time, theoretically indicating a hypertensive condition, was more frequently associated with severe variable decelerations, suggesting that the pulse transit time may supplement the interpretation of fetal heart rate monitoring.

Diurnal changes in the power spectral characteristics of eye movements and heart rate variability in the human fetus at term.

PubMed

Morokuma, S; Horimoto, N; Nakano, H

2001-08-01

It is well known that 1/f characteristics in power spectral patterns exist in various biological factors including heart rate variability. In the present study, we tried to elucidate the diurnal variation in spectral properties of eye movement and heart rate variability in the human fetus at term, via continuous 24-h observation of both these parameters. Studied were five uncomplicated fetuses at term. We observed eye movement and fetal heart rate (FHR) with real-time ultrasound and Doppler cardiotocograph, respectively, and analyzed the diurnal change in spectral properties, using the maximum entropy method. In four of five cases, the slope values of power spectra for both eye movement frequency and FHR, ranging approximately between 0.5 and 1.8, indicated diurnal variation, where the slopes tended to have high values during the day and low values at night. These findings suggest that, in the human fetus at term, eye movement and FHR are under the control of a common central mechanism, and this center changes its complexity as seen through diurnal rhythm.

Short-term variability of blood pressure and heart rate in hyperthyroidism.

PubMed

Girard, A; Hugues, F C; Le Jeunne, C; Elghozi, J L

1998-06-01

The effect of hyperthyroidism on the short-term memory variability of blood pressure and heart rate was evaluated in 12 untreated hyperthyroid patients during thyrotoxicosis and after a 6 1/2 month treatment designed to achieve a stable euthyroid state. Beat-by-beat finger blood pressure was measured with a Finapres device. The pulse interval, from which pulse rate was derived, was obtained from the blood pressure signal. Due to the significant change in heart rhythm associated with thyrotoxicosis, both pulse interval (taken as a surrogate of heart period) and pulse rate (taken as a surrogate of heart rate) were computed. Power spectral analysis showed a reduction in the overall heart period variability in the supine position in the hyperthyroid compared to the euthyroid state. This effect was observed in the low-frequency (0.005-0.068 Hz), mid-frequency (0.068-0.127 Hz) and high-frequency (respiratory) domains as well, with a significant reduction of the modulus of these bands of 31%, 35% and 47%, respectively. The heart rate spectral modulus also exhibited a reduction of the high-frequency component (31%) in the supine position in the hyperthyroid subjects. These changes in heart rhythmicity corroborate a vagal deficit in hyperthyroidism. In addition, blood pressure spectral power exhibited a significant deficit in the orthostatism-induced mid-frequency systolic blood pressure rise in the hyperthyroid state (64%) compared with the euthyroid state. This observation may reflect a reduced vascular sympathetic activation with standing. The resulting vasodilatation could well contribute to normalize blood pressure in thyrotoxicosis in which cardiac output is increased.

Chronic intermittent hypoxia-hypercapnia blunts heart rate responses and alters neurotransmission to cardiac vagal neurons.

PubMed

Dyavanapalli, Jhansi; Jameson, Heather; Dergacheva, Olga; Jain, Vivek; Alhusayyen, Mona; Mendelowitz, David

2014-07-01

Patients with obstructive sleep apnoea experience chronic intermittent hypoxia-hypercapnia (CIHH) during sleep that elicit sympathetic overactivity and diminished parasympathetic activity to the heart, leading to hypertension and depressed baroreflex sensitivity. The parasympathetic control of heart rate arises from pre-motor cardiac vagal neurons (CVNs) located in nucleus ambiguus (NA) and dorsal motor nucleus of the vagus (DMNX). The mechanisms underlying diminished vagal control of heart rate were investigated by studying the changes in blood pressure, heart rate, and neurotransmission to CVNs evoked by acute hypoxia-hypercapnia (H-H) and CIHH. In vivo telemetry recordings of blood pressure and heart rate were obtained in adult rats during 4 weeks of CIHH exposure. Retrogradely labelled CVNs were identified in an in vitro brainstem slice preparation obtained from adult rats exposed either to air or CIHH for 4 weeks. Postsynaptic inhibitory or excitatory currents were recorded using whole cell voltage clamp techniques. Rats exposed to CIHH had increases in blood pressure, leading to hypertension, and blunted heart rate responses to acute H-H. CIHH induced an increase in GABAergic and glycinergic neurotransmission to CVNs in NA and DMNX, respectively; and a reduction in glutamatergic neurotransmission to CVNs in both nuclei. CIHH blunted the bradycardia evoked by acute H-H and abolished the acute H-H evoked inhibition of GABAergic transmission while enhancing glycinergic neurotransmission to CVNs in NA. These changes with CIHH inhibit CVNs and vagal outflow to the heart, both in acute and chronic exposures to H-H, resulting in diminished levels of cardioprotective parasympathetic activity to the heart as seen in OSA patients. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Heart rate changes during electroconvulsive therapy

PubMed Central

2013-01-01

Background This observational study documented heart rate over the entire course of electrically induced seizures and aimed to evaluate the effects of stimulus electrode placement, patients' age, stimulus dose, and additional predictors. Method In 119 consecutive patients with 64 right unilateral (RUL) and 55 bifrontal (BF) electroconvulsive treatments, heart rate graphs based on beat-to-beat measurements were plotted up to durations of 130 s. Results In RUL stimulation, the initial drop in heart rate lasted for 12.5 ± 2.6 s (mean ± standard deviation). This depended on stimulus train duration, age, and baseline heart rate. In seizures induced with BF electrode placement, a sympathetic response was observed within the first few seconds of the stimulation phase (median 3.5 s). This was also the case with subconvulsive stimulations. The mean peak heart rate in all 119 treatments amounted to 135 ± 20 bpm and depended on baseline heart rate and seizure duration; electrode placement, charge dose, and age were insignificant in regression analysis. A marked decline in heart rate in connection with seizure cessation occurred in 71% of treatments. Conclusions A significant independent effect of stimulus electrode positioning on cardiac action was evident only in the initial phase of the seizures. Electrical stimulation rather than the seizure causes the initial heart rate increase in BF treatments. The data reveal no rationale for setting the stimulus doses as a function of intraictal peak heart rates (‘benchmark method’). The marked decline in heart rate at the end of most seizures is probably mediated by a baroreceptor reflex. PMID:23764036

Field test of a paradigm: hysteresis of heart rate in thermoregulation by a free-ranging lizard (Pogona barbata).

PubMed Central

Grigg, G C; Seebacher, F

1999-01-01

The discovery that changes in heart rate and blood flow allow some reptiles to heat faster than they cool has become a central paradigm in our understanding of reptilian thermoregulation. However, this hysteresis in heart rate has been demonstrated only in simplistic laboratory heating and cooling trials, leaving its functional significance in free-ranging animals unproven. To test the validity of this paradigm, we measured heart rate and body temperature (Tb) in undisturbed, free-ranging bearded dragons (Pogona barbata), the species in which this phenomenon was first described. Our field data confirmed the paradigm and we found that heart rate during heating usually exceeded heart rate during cooling at any Tb. Importantly, however, we discovered that heart rate was proportionally faster in cool lizards whose Tb was still well below the 'preferred Tb range' compared to lizards whose Tb was already close to it. Similarly, heart rate during cooling was proportionally slower the warmer the lizard and the greater its cooling potential compared to lizards whose Tb was already near minimum operative temperature. Further, we predicted that, if heart rate hysteresis has functional significance, a 'reverse hysteresis' pattern should be observable when lizards risked overheating. This was indeed the case and, during heating on those occasions when Tb reached very high levels (> 40 degrees C), heart rate was significantly lower than heart rate during the immediately following cooling phase. These results demonstrate that physiological control of thermoregulation in reptiles is more complex than has been previously recognized. PMID:10418165

Energy expenditure in frontotemporal dementia: a behavioural and imaging study

PubMed Central

Ahmed, Rebekah M; Landin-Romero, Ramon; Collet, Tinh-Hai; van der Klaauw, Agatha A; Devenney, Emma; Henning, Elana; Kiernan, Matthew C; Piguet, Olivier; Farooqi, I Sadaf; Hodges, John R

2017-01-01

Abstract See Finger (doi:10.1093/aww312) for a scientific commentary on this article. Abnormal eating behaviour and metabolic parameters including insulin resistance, dyslipidaemia and body mass index are increasingly recognized as important components of neurodegenerative disease and may contribute to survival. It has previously been established that behavioural variant frontotemporal dementia is associated with abnormal eating behaviour characterized by increased sweet preference. In this study, it was hypothesized that behavioural variant frontotemporal dementia might also be associated with altered energy expenditure. A cohort of 19 patients with behavioural variant frontotemporal dementia, 13 with Alzheimer’s disease and 16 (age- and sex-matched) healthy control subjects were studied using Actiheart devices (CamNtech) to assess resting and stressed heart rate. Actiheart devices were fitted for 7 days to measure sleeping heart rate, activity levels, and resting, active and total energy expenditure. Using high resolution structural magnetic resonance imaging the neural correlates of increased resting heart rate were investigated including cortical thickness and region of interest analyses. In behavioural variant frontotemporal dementia, resting (P = 0.001), stressed (P = 0.037) and sleeping heart rate (P = 0.038) were increased compared to control subjects, and resting heart rate (P = 0.020) compared to Alzheimer disease patients. Behavioural variant frontotemporal dementia was associated with decreased activity levels compared to controls (P = 0.002) and increased resting energy expenditure (P = 0.045) and total energy expenditure (P = 0.035). Increased resting heart rate correlated with behavioural (Cambridge Behavioural Inventory) and cognitive measures (Addenbrooke’s Cognitive Examination). Increased resting heart rate in behavioural variant frontotemporal dementia correlated with atrophy involving the mesial temporal cortex, insula, and amygdala, regions previously suggested to be involved exclusively in social and emotion processing in frontotemporal dementia. These neural correlates overlap the network involved in eating behaviour in frontotemporal dementia, suggesting a complex interaction between eating behaviour, autonomic function and energy homeostasis. As such the present study suggests that increased heart rate and autonomic changes are prevalent in behavioural variant frontotemporal dementia, and are associated with changes in energy expenditure. An understanding of these changes and neural correlates may have potential relevance to disease progression and prognosis. PMID:27789521

Long-Term Coarse Particulate Matter Exposure and Heart Rate Variability in the Multi-Ethnic Study of Atherosclerosis (MESA)

PubMed Central

Adhikari, Richa; D’Souza, Jennifer; Solimon, Elsayed Z.; Burke, Gregory L.; Daviglus, Martha; Jacobs, David R.; Park, Sung Kyun; Sheppard, Lianne; Thorne, Peter S.; Kaufman, Joel D.; Larson, Timothy V.; Adar, Sara D.

2017-01-01

Background Reduced heart rate variability, a marker of impaired cardiac autonomic function, has been linked to short-term exposure to airborne particles. This research adds to the literature by examining associations with long-term exposures to coarse particles (PM10-2.5). Methods Using electrocardiogram recordings from 2,780 participants (45-84 years) from three Multi-Ethnic Study of Atherosclerosis sites, we assessed the standard deviation of normal-to-normal intervals (SDNN) and root-mean square differences of successive normal-to-normal intervals (rMSSD) at a baseline (2000-2002) and follow-up (2010-2012) examination (mean visits/person=1.5). Annual average concentrations of PM10-2.5 mass, copper, zinc, phosphorus, silicon, and endotoxin were estimated using site-specific spatial prediction models. We assessed associations for baseline heart rate variability and rate of change in heart rate variability over time using multivariable mixed models adjusted for time, sociodemographic, lifestyle, health, and neighborhood confounders, including co-pollutants. Results In our primary models adjusted for demographic and lifestyle factors and site, PM10-2.5 mass was associated with 1.0% (95% CI: -4.1, 2.1%) lower SDNN levels per interquartile range of 2 μg/m3. Stronger associations, however, were observed prior to site adjustment and with increasing residential stablity. Similar patterns were found for rMSSD. We found little evidence for associations with other chemical species and with with the rate of change in heart rate variability, though endotoxin was associated with increasing heart rate variability over time. Conclusion We found only weak evidence that long-term PM10-2.5 exposures are associated with lowered heart rate variability. Stronger associations among residentially stable individuals suggest that confirmatory studies are needed. PMID:27035690

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.

CHANGES IN HEART RATE VARIABILITY AND LUNG FUNCTION OBSERVED IN NC PATROL TROOPERS EXPOSED TO PM AND AIR TOXICS

EPA Science Inventory

Changes in Heart Rate Variability and Lung Function in NC Patrol Troopers exposed to PM and Air Toxics

Michael Riediker1, Wayne E Cascio1, Robert B Devlin2, Thomas Griggs1&4, Margaret Herbst1, Ronald W Williams3, Steve P McCorquodale4, Philip A Bromberg1
1) University o...

Early-onset neonatal sepsis is associated with a high heart rate during automatically selected stationary periods.

PubMed

Nguyen, Nga; Vandenbroucke, Laurent; Hernández, Alfredo; Pham, Tu; Beuchée, Alain; Pladys, Patrick

2017-05-01

This study examined the heart rate variability characteristics associated with early-onset neonatal sepsis in a prospective, observational controlled study. Eligible patients were full-term neonates hospitalised with clinical signs that suggested early-onset sepsis and a C-reactive protein of >10 mg/L. Sepsis was considered proven in cases of symptomatic septicaemia, meningitis, pneumonia or enterocolitis. Heart rate variability parameters (n = 16) were assessed from five-, 15- and 30-minute stationary sequences automatically selected from electrocardiographic recordings performed at admission and compared with a control group using the U-test with post hoc Benjamini-Yekutieli correction. Stationary sequences corresponded to the periods with the lowest changes of heart rate variability over time. A total of 40 full-term infants were enrolled, including 14 with proven sepsis. The mean duration of the cardiac cycle length was lower in the proven sepsis group than in the control group (n = 11), without other significant changes in heart rate variability parameters. These durations, measured in five-minute stationary periods, were 406 (367-433) ms in proven sepsis group versus 507 (463-522) ms in the control group (p < 0.05). Early-onset neonatal sepsis was associated with a high mean heart rate measured during automatically selected stationary periods. ©2017 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

The within-participant correlation between perception of effort and heart rate-based estimations of training load in elite soccer players.

PubMed

Kelly, David M; Strudwick, Anthony J; Atkinson, Greg; Drust, Barry; Gregson, Warren

2016-07-01

The measurement of relative physiological stress during training is important because this is the stimulus for the long-term adaptive response. Measurements of perceived exertion (RPE) have been reported to correlate with the heart rate during field-based training sessions. Nevertheless, there are few studies on how well RPE tracks with the heart rate over repeated training sessions in elite soccer players. Therefore, we aimed to quantify the within-participant correlations between variability in session-RPE (sRPE) and the heart rate in elite male soccer players, and to determine whether the playing position moderated these correlations. The field-based training of four central defenders, four wide defenders, six central midfielders, two wide midfielders and three attackers from an elite English Premier League squad were monitored over an entire in-season competitive period, giving a total of 1010 individual training sessions for study. Correlations between session-RPE and heart rates were quantified using a within-participant model. The correlation between changes in sRPE and heart rates was r = 0.75 (95% CI: 0.71-0.78). This correlation remained high across the various player positions (wide-defender, r = 0.81; central-defender, r = 0.74; wide midfielder, r = 0.70; central midfielder, r = 0.70; attacker, r = 0.84; P < 0.001). The correlation between changes in RPE and heart rates, measured during a season-long period of field-based training, is high in a sample of elite soccer players.

Systemic effects of an intraosseous injection of 2% lidocaine with 1:100,000 epinephrine.

PubMed

Chamberlain, T M; Davis, R D; Murchison, D F; Hansen, S R; Richardson, B W

2000-01-01

The effect of a mandibular intraosseous injection of 2% lidocaine with 1:100,000 epinephrine on the heart rate and blood pressure of 20 volunteer patients was examined. Changes in blood pressure from preoperative levels were minimal and did not vary significantly at any time of measurement. The only statistically significant change in heart rate occurred immediately after the intraosseous injection (an increase of 12 beats per minute). In young healthy adults, the intraosseous injection of 1.5 mL of 2% lidocaine with 1:100,000 epinephrine resulted in a slight transient elevation in heart rate but had no significant effect on systolic or diastolic blood pressure.

Investigation of the effect of occupational noise exposure on blood pressure and heart rate of steel industry workers.

PubMed

Zamanian, Zahra; Rostami, Reza; Hasanzadeh, Jafar; Hashemi, Hassan

2013-01-01

This study aimed to investigate the effect of noise exposure on blood pressure and heart rate of steel industry workers. In the present cross-sectional study, 50 workers were selected from a steel company in Fars province, Iran, and exposed to 85, 95, and 105 dB noise levels for 5 minutes. The participants' blood pressure and heart rate were measured using Beurer BC16 pulse meter both before and after the exposure. The study results showed no significant difference in blood pressure and heart rate before and after the exposure. However, the workers' systolic blood pressure had increased compared to before the exposure; of course, the difference was not statistically significant (P > 0.05). Besides, although the subjects' heart rate had reduced in comparison to before the exposure, the difference was not statistically significant (P > 0.05). No significant change was observed in blood pressure and heart rate after acute exposure to 85, 95, and 105 dB noise levels.

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

PubMed Central

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. PMID:7488453

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.

Pain and cardiorespiratory responses of children during physiotherapy after heart surgery.

PubMed

Araujo, Adriana Sanches Garcia; Klamt, Jyrson Guilherme; Vicente, Walter Villela de Andrade; Garcia, Luis Vicente

2014-01-01

The aim of the present study was to determine the occurrence of pain and changes in blood pressure, heart rate, respiratory rate, and arterial oxygen saturation associated with physiotherapy in children undergoing cardiac surgery. Eighteen extubated children were assessed for the presence of pain using the face, legs, activity, cry, consolability scale, and blood pressure, heart rate, respiratory rate and arterial oxygen saturation were simultaneously recorded. The physiological parameters were measured at the following time periods: immediately before physiotherapy, five and 10 minutes after the beginning of physiotherapy, and five minutes after its end. Pain was assessed immediately before physiotherapy, ten minutes after the beginning of physiotherapy and five minutes after its end. Pain and physiological changes were assessed by the Friedman test and the correlation between the physiological parameters and the pain scores was assessed by the Spearman test. Pain increased during physiotherapy and decreased significantly after it compared to pre-physiotherapy scores. Systolic blood pressure and heart rate increased significantly after 10 minutes of the beginning of physiotherapy. Arterial oxygen saturation tended to decrease during physiotherapy and to increase after it, although without significance. The correlation between pain scores and the physiological variables was significant only for systolic blood pressure and heart rate ten minutes after the beginning of physiotherapy. Manipulation after the beginning of physiotherapy seems to be accompanied by significant pain and by important associated cardiovascular changes. Apparent analgesia and improved respiratory function were observed after respiratory physiotherapy.

Serial optical coherence scanning reveals an association between cardiac function and the heart architecture in the aging rodent heart

PubMed Central

Castonguay, Alexandre; Lefebvre, Joël; Pouliot, Philippe; Avti, Pramod; Moeini, Mohammad; Lesage, Frédéric

2017-01-01

Normal aging is accompanied by structural changes in the heart architecture. To explore this remodeling, we used a serial optical coherence tomography scanner to image entire mouse hearts at micron scale resolution. Ex vivo hearts of 7 young (4 months) and 5 old (24 months) C57BL/6 mice were acquired with the imaging platform. OCT of the myocardium revealed myofiber orientation changing linearly from the endocardium to the epicardium. In old mice, this rate of change was lower when compared to young mice while the average volume of old mice hearts was significantly larger (p<0.05). Myocardial wall thickening was also accompanied by extracellular spacing in the endocardium, resulting in a lower OCT attenuation coefficient in old mice endocardium (p<0.05). Prior to serial sectioning, cardiac function of the same hearts was imaged in vivo using MRI and revealed a reduced ejection fraction with aging. The use of a serial optical coherence tomography scanner allows new insight into fine age-related changes of the heart associated with changes in heart function. PMID:29188099

A dose-response study of dexmedetomidine administered as the primary sedative in infants following open heart surgery.

PubMed

Su, Felice; Nicolson, Susan C; Zuppa, Athena F

2013-06-01

To evaluate the dose-response relationship of dexmedetomidine in infants with congenital heart disease postoperative from open heart surgery. Prospective open-label dose-escalation pharmacokinetic-pharmacodynamic study. Tertiary pediatric cardiac ICU. Thirty-six evaluable infants, 1-24 months old, postoperative from open heart surgery requiring mechanical ventilation. Cohorts of 12 infants were enrolled sequentially to one of the three IV loading doses of dexmedetomidine (0.35, 0.7, and 1 mcg/kg) over 10 minutes followed by respective continuous infusions (0.25, 0.5, and 0.75 mcg/kg/hr) for up to 24 hours. Dexmedetomidine plasma concentrations were obtained at timed intervals during and following discontinuation of infusion. Pharmacodynamic variables evaluated included sedation scores, supplemental sedation and analgesia medication administration, time to tracheal extubation, respiratory function, and hemodynamic parameters. Infants achieved a deeper sedation measured by the University of Michigan Sedation Scale score (2.6 vs 1) despite requiring minimal supplemental sedation (0 unit doses/hr) and fewer analgesic medications (0.07 vs 0.15 unit doses/hr) while receiving dexmedetomidine compared with the 12-hour follow-up period. Thirty-one patients were successfully extubated while receiving the dexmedetomidine infusion. Only one patient remained intubated due to oversedation during the infusion. While receiving dexmedetomidine, there was a decrease in heart rate compared with baseline, 132 versus 161 bpm, but there was an increase in heart rate compared with postinfusion values, 132 versus 128 bpm. There was no statistically or clinically significant change in mean arterial blood pressure. Dexmedetomidine administration in infants following open heart surgery can provide improved sedation with reduction in supplemental medication requirements, leading to successful extubation while receiving a continuous infusion. The postoperative hemodynamic changes that occur in infants postoperative from open heart surgery are multifactorial. Although dexmedetomidine may play a role in decreasing heart rate immediately postoperative, the changes were not clinically significant and did not fall below postinfusion heart rates.

Resting Heart Rate as Predictor for Left Ventricular Dysfunction and Heart Failure: The Multi-Ethnic Study of Atherosclerosis

PubMed Central

Opdahl, Anders; Venkatesh, Bharath Ambale; Fernandes, Veronica R. S.; Wu, Colin O.; Nasir, Khurram; Choi, Eui-Young; Almeida, Andre L. C.; Rosen, Boaz; Carvalho, Benilton; Edvardsen, Thor; Bluemke, David A.; Lima, Joao A. C.

2014-01-01

OBJECTIVE To investigate the relationship between baseline resting heart rate and incidence of heart failure (HF) and global and regional left ventricular (LV) dysfunction. BACKGROUND The association of resting heart rate to HF and LV function is not well described in an asymptomatic multi-ethnic population. METHODS Participants in the Multi-Ethnic Study of Atherosclerosis had resting heart rate measured at inclusion. Incident HF was registered (n=176) during follow-up (median 7 years) in those who underwent cardiac MRI (n=5000). Changes in ejection fraction (ΔEF) and peak circumferential strain (Δεcc) were measured as markers of developing global and regional LV dysfunction in 1056 participants imaged at baseline and 5 years later. Time to HF (Cox model) and Δεcc and ΔEF (multiple linear regression models) were adjusted for demographics, traditional cardiovascular risk factors, calcium score, LV end-diastolic volume and mass in addition to resting heart rate. RESULTS Cox analysis demonstrated that for 1 bpm increase in resting heart rate there was a 4% greater adjusted relative risk for incident HF (Hazard Ratio: 1.04 (1.02, 1.06 (95% CI); P<0.001). Adjusted multiple regression models demonstrated that resting heart rate was positively associated with deteriorating εcc and decrease in EF, even in analyses when all coronary heart disease events were excluded from the model. CONCLUSION Elevated resting heart rate is associated with increased risk for incident HF in asymptomatic participants in MESA. Higher heart rate is related to development of regional and global LV dysfunction independent of subclinical atherosclerosis and coronary heart disease. PMID:24412444

Comparison between the effects of inhaled isoprenaline and fenoterol on plasma cyclic AMP and heart rate in normal subjects.

PubMed Central

Fairfax, A J; Rehahn, M; Jones, D; O'Malley, B

1984-01-01

The time course of changes in plasma cyclic AMP, heart rate and bronchial tone after inhalation of fenoterol or isoprenaline from a dose-metered aerosol are reported in a group of normal subjects. After isoprenaline, plasma cyclic AMP increased rapidly reaching a peak by 10 min and returned to basal levels within 60 min. A rapid, transient rise in heart rate occurred that was maximal by 5 min and returned to a basal level by 45 min. After fenoterol, the changes in cyclic AMP and heart rate were of much longer duration. The rise in plasma cyclic AMP was slower in onset and of greater magnitude than for isoprenaline, reaching a peak by 20 min and remaining above basal level for more than 6 h. The maximum increase in heart rate after fenoterol was less than that observed with isoprenaline but an elevated rate persisted for 4 h after inhalation of fenoterol. Fenoterol is known to have a longer duration of action as a bronchodilator in comparison with isoprenaline. The prolonged rise in plasma cyclic AMP in normal subjects given inhaled fenoterol may reflect this long duration of action. The concomitant rise in heart rate, however, suggests that the duration of plasma cyclic AMP response may in part be due to the systemic effect of the fraction of inhaled fenoterol known to be absorbed via the buccal and intestinal routes. PMID:6322828

The short-term effect of smoking on fetal ECG.

PubMed

Péterfi, István; Kellényi, Lóránd; Péterfi, Lehel; Szilágyi, András

2017-10-26

The number of women who smoke during pregnancy is significant even today. The harmful effects of smoking during pregnancy are well known but there are no data on the effects of smoking on fetal electrocardiography (ECG). The lack of data is in connection with the difficulties of recording fetal ECG through the maternal abdomen. Third trimester pregnant women who were not able to give up the harmful passion of smoking despite repeated attempts of persuasion were recruited in the study on voluntary basis. The fetal ECG was recorded non-invasively through the maternal abdomen before, during and after smoking, then the data were processed offline. The electrophysiological measurements were performed by a self developed ECG device, which allowed the examination of the morphological differences in "true-to-form" fetal ECG in addition to studying the variability of fetal heart rate. The study involved nine pregnant women. The observed changes are presented through case studies of those pregnant women who showed the most significant anomalies. Compared with the resting state fetal heart rate was increased during smoking. The short-term variability of fetal heart rate was narrowed, while the mother's heart rate did not change significantly - which was an indication of direct fetal stress. No explicit ischemic signs were detected in fetal ECG during smoking, however, in the increasing period of the fetal heart rate, the T wave morphology changed slightly, then it returned to normal. Demonstrable by the electrophysiological methods, smoking has a direct effect on fetal cardiac function. The fetal heart rate variability shows a pattern during smoking which is a typical sign of stress conditions among adults. The results may have educational consequences as well. Understanding those, hopefully will help pregnant women give up this harmful addiction.

Three Weeks of Overload Training Increases Resting Muscle Sympathetic Activity.

PubMed

Coates, Alexandra M; Incognito, Anthony V; Seed, Jeremy D; Doherty, Connor J; Millar, Philip J; Burr, Jamie F

2018-05-01

Overload training is hypothesized to alter autonomic regulation, although interpretations using indirect measures of heart rate variability are conflicting. The aim of the present study was to examine the effects of overload training on muscle sympathetic nerve activity (MSNA), a direct measure of central sympathetic outflow, in recreational endurance athletes. Measurements of heart rate variability, cardiac baroreflex sensitivity (BRS), MSNA (microneurography), and sympathetic BRS were obtained in 17 healthy triathletes and cyclists after 1 wk of reduced training (baseline) and again after 3 wk of either regular (n = 7) or overload (n = 10) training. After training, the changes (Δ) in peak power output (10 ± 10 vs -12 ± 9 W, P < 0.001), maximal heart rate (-2 ± 4 vs -8 ± 3 bpm, P = 0.006), heart rate variability (SD of normal-to-normal intervals, 27 ± 31 vs -3 ± 25 ms; P = 0.04), and cardiac BRS (7 ± 6 vs -2 ± 8 ms·mm Hg, P = 0.02) differed between the control and overload groups. The change in MSNA burst frequency (-2 ± 2 vs 4 ± 5 bursts per minute, P = 0.02) differed between groups. Across all participants, the changes in resting MSNA and peak power output were correlated negatively (r = -0.51, P = 0.04). No between-group differences in resting heart rate or blood pressure were observed (all P > 0.05). Overload training increased MSNA and attenuated increases in cardiac BRS and heart rate variability observed with regular training. These results support neural adaptations after overload training and suggest that increased central sympathetic outflow may be linked with decreased exercise performance.

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. © 2013.

Heart Rate Variability Responses of a Preterm Infant to Kangaroo Care

PubMed Central

McCain, Gail C.; Ludington-Hoe, Susan M.; Swinth, Joan Y.; Hadeed, Anthony J.

2006-01-01

A 35-week old preterm infant's behavior was fussy and restless in the open crib, but he calmed and fell asleep immediately on being placed skin-to-skin on his mother's chest. Heart rate variability (HRV), a noninvasive method to assess the autonomic nervous system's influence on heart rate, was increased with fussy behavior in the open crib and decreased with sleep during kangaroo care (KC). KC produced changes in behavior and HRV that are illustrative of decreasing stress. PMID:16282226

Effect of Selective Heart Rate Slowing in Heart Failure With Preserved Ejection Fraction.

PubMed

Pal, Nikhil; Sivaswamy, Nadiya; Mahmod, Masliza; Yavari, Arash; Rudd, Amelia; Singh, Satnam; Dawson, Dana K; Francis, Jane M; Dwight, Jeremy S; Watkins, Hugh; Neubauer, Stefan; Frenneaux, Michael; Ashrafian, Houman

2015-11-03

Heart failure with preserved ejection fraction (HFpEF) is associated with significant morbidity and mortality but is currently refractory to therapy. Despite limited evidence, heart rate reduction has been advocated, on the basis of physiological considerations, as a therapeutic strategy in HFpEF. We tested the hypothesis that heart rate reduction improves exercise capacity in HFpEF. We conducted a randomized, crossover study comparing selective heart rate reduction with the If blocker ivabradine at 7.5 mg twice daily versus placebo for 2 weeks each in 22 symptomatic patients with HFpEF who had objective evidence of exercise limitation (peak oxygen consumption at maximal exercise [o2 peak] <80% predicted for age and sex). The result was compared with 22 similarly treated matched asymptomatic hypertensive volunteers. The primary end point was the change in o2 peak. Secondary outcomes included tissue Doppler-derived E/e' at echocardiography, plasma brain natriuretic peptide, and quality-of-life scores. Ivabradine significantly reduced peak heart rate compared with placebo in the HFpEF (107 versus 129 bpm; P<0.0001) and hypertensive (127 versus 145 bpm; P=0.003) cohorts. Ivabradine compared with placebo significantly worsened the change in o2 peak in the HFpEF cohort (-2.1 versus 0.9 mL·kg(-1)·min(-1); P=0.003) and significantly reduced submaximal exercise capacity, as determined by the oxygen uptake efficiency slope. No significant effects on the secondary end points were discernable. Our observations bring into question the value of heart rate reduction with ivabradine for improving symptoms in a HFpEF population characterized by exercise limitation. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02354573. © 2015 The Authors.

Control plasma renin activity and changes in sympathetic tone as determinants of minoxidil-induced increase in plasma renin activity.

PubMed Central

O'Malley, K; Velasco, M; Wells, J; McNay, J L

1975-01-01

A study was made of the possible mechanism(s) underlying minoxidil-induced increase in plasma renin activity (PRA). 10 patients with essential hypertension were treated with minoxidil and subsequently with a combination of minoxidil plus propranolol. Minoxidil lowered mean arterial pressure 31.6 plus or minus 3.3 mm Hg, mean plus or minus SEM. There was an associated increase in both PRA, 6.26 plus or minus 2.43 NG/ML/H, and heart rate, 21.4 plus or minus 2.7 beats/min. The changes in PRA and heart rate were positively correlated, r, 0.79. Addition of propranolol reduced mean arterial pressure by a further 10.1 plus or minus 1.5 mm Hg and returned heart rate to control levels. Propranolol reduced PRA significantly but not to control levels. Control PRA positively correlated with PRA on minoxidil, r, 0.97, and with PRA on minoxidil plus propranolol, r, 0.98. We conclude that control PRA is a major determinant of change in PRA with minoxidil. Minoxidil increased PRA by at least two mechanisms: (a) an adrenergic mechanism closely related to change in heart rate and blocked by propranolol, and (b) a mechanism(s) not sensitive to propranolol and possibly related to decrease in renal perfusion pressure. PMID:1127099

Massage therapy of moderate and light pressure and vibrator effects on EEG and heart rate.

PubMed

Diego, Miguel A; Field, Tiffany; Sanders, Chris; Hernandez-Reif, Maria

2004-01-01

Three types of commonly used massage therapy techniques were assessed in a sample of 36 healthy adults, randomly assigned to: (1) moderate massage, (2) light massage, or (3) vibratory stimulation group (n = 12 per group). Changes in anxiety and stress were assessed, and EEG and EKG were recorded. Anxiety scores decreased for all groups, but the moderate pressure massage group reported the greatest decrease in stress. The moderate massage group also experienced a decrease in heart rate and EEG changes including an increase in delta and a decrease in alpha and beta activity, suggesting a relaxation response. Finally, this group showed increased positive affect, as indicated by a shift toward left frontal EEG activation. The light massage group showed increased arousal, as indicated by decreased delta and increased deta activity and increased heart rate. The vibratory stimulation group also showed increased arousal, as indicated by increased heart rate and increased theta, alpha, and beta activity.

Psychophysiological responses to auditory change.

PubMed

Chuen, Lorraine; Sears, David; McAdams, Stephen

2016-06-01

A comprehensive characterization of autonomic and somatic responding within the auditory domain is currently lacking. We studied whether simple types of auditory change that occur frequently during music listening could elicit measurable changes in heart rate, skin conductance, respiration rate, and facial motor activity. Participants heard a rhythmically isochronous sequence consisting of a repeated standard tone, followed by a repeated target tone that changed in pitch, timbre, duration, intensity, or tempo, or that deviated momentarily from rhythmic isochrony. Changes in all parameters produced increases in heart rate. Skin conductance response magnitude was affected by changes in timbre, intensity, and tempo. Respiratory rate was sensitive to deviations from isochrony. Our findings suggest that music researchers interpreting physiological responses as emotional indices should consider acoustic factors that may influence physiology in the absence of induced emotions. © 2016 Society for Psychophysiological Research.

Influence of energy drinks and alcohol on post-exercise heart rate recovery and heart rate variability.

PubMed

Wiklund, Urban; Karlsson, Marcus; Oström, Mats; Messner, Torbjörn

2009-01-01

Media have anecdotally reported that drinking energy drinks in combination with alcohol and exercise could cause sudden cardiac death. This study investigated changes in the electrocardiogram (ECG) and heart rate variability after intake of an energy drink, taken in combination with alcohol and exercise. Ten healthy volunteers (five men and five women aged 19-30) performed maximal bicycle ergometer exercise for 30 min after: (i) intake of 0.75 l of an energy drink mixed with alcohol; (ii) intake of energy drink; and, (iii) no intake of any drink. ECG was continuously recorded for analysis of heart rate variability and heart rate recovery. No subject developed any clinically significant arrhythmias. Post-exercise recovery in heart rate and heart rate variability was slower after the subjects consumed energy drink and alcohol before exercise, than after exercise alone. The healthy subjects developed blunted cardiac autonomic modulation after exercising when they had consumed energy drinks mixed with alcohol. Although they did not develop any significant arrhythmia, individuals predisposed to arrhythmia by congenital or other rhythm disorders could have an increased risk for malignant cardiac arrhythmia in similar situations.

Balancing tissue perfusion demands: cardiovascular dynamics of Cancer magister during exposure to low salinity and hypoxia.

PubMed

McGaw, Iain J; McMahon, Brian R

2003-01-01

Decapod crustaceans inhabit aquatic environments that are frequently subjected to changes in salinity and oxygen content. The physiological responses of decapod crustaceans to either salinity or hypoxia are well documented; however, there are many fewer reports on the physiological responses during exposure to these parameters in combination. We investigated the effects of simultaneous and sequential combinations of low salinity and hypoxia on the cardiovascular physiology of the Dungeness crab, Cancer magister. Heart rate, as well as haemolymph flow rates through the anterolateral, hepatic, sternal and posterior arteries were measured using a pulsed-Doppler flowmeter. Summation of flows allowed calculation of cardiac output and division of this by heart rate yielded stroke volume. When hypoxia and low salinity were encountered simultaneously, the observed changes in cardiac properties tended to be a mix of both factors. Hypoxia caused a bradycardia, whereas exposure to low salinity was associated with a tachycardia. However, the hypoxic conditions had the dominant effect on heart rate. Although hypoxia caused an increase in stroke volume of the heart, the low salinity had a more pronounced effect, causing an overall decrease in stroke volume. The patterns of haemolymph flow through the arterial system also varied when hypoxia and low salinity were offered together. The resulting responses were a mix of those resulting from exposure to either parameter alone. When low salinity and hypoxia were offered sequentially, the parameter experienced first tended to have the dominant effect on cardiac function and haemolymph flows. Low salinity exposure was associated with an increase in heart rate, a decrease in stroke volume and cardiac output, and a concomitant decrease in haemolymph flow rates. Subsequent exposure to hypoxic conditions caused a slight decrease in rate, but other cardiovascular variables were largely unaffected. In contrast, when low salinity followed acclimation to hypoxic conditions, apart from an increased heart rate, there were no other cardiovascular changes associated with the low salinity episode. The implications of these changes in cardiovascular dynamics are discussed in relation to physiological mechanisms and the ecology of decapod crustaceans, in hypoxic or low salinity environments. Copyright 2003, Wiley-Liss, Inc.

Changes in Blood Pressure and Heart Rate during Fixed-Interval Responding in Squirrel Monkeys

ERIC Educational Resources Information Center

DeWeese, Jo

2009-01-01

Episodic and sustained increases in heart rate and mean arterial blood pressure can occur with recurring patterns of schedule-controlled behavior. Most previous studies were conducted under fixed-ratio schedules, which maintained a consistent high rate of responding that alternated with periods of no responding during times when the schedule was…

Hysteresis of heart rate and heat exchange of fasting and postprandial savannah monitor lizards (Varanus exanthematicus).

PubMed

Zaar, Morten; Larsen, Einer; Wang, Tobias

2004-04-01

Reptiles are ectothermic, but regulate body temperatures (T(b)) by behavioural and physiological means. Body temperature has profound effects on virtually all physiological functions. It is well known that heating occurs faster than cooling, which seems to correlate with changes in cutaneous perfusion. Increased cutaneous perfusion, and hence elevated cardiac output, during heating is reflected in an increased heart rate (f(H)), and f(H), at a given T(b), is normally higher during heating compared to cooling ('hysteresis of heart rate'). Digestion is associated with an increased metabolic rate. This is associated with an elevated f(H) and many species of reptiles also exhibited a behavioural selection of higher T(b) during digestion. Here, we examine whether digestion affects the rate of heating and cooling as well as the hysteresis of heart rate in savannah monitor lizards (Varanus exanthematicus). Fasting lizards were studied after 5 days of food deprivation while digesting lizards were studied approximately 24 h after ingesting dead mice that equalled 10% of their body mass. Heart rate was measured while T(b) increased from 28 to 38 degrees C under a heat lamp and while T(b) decreased during a subsequent cooling phase. The lizards exhibited hysteresis of heart rate, and heating occurred faster than cooling. Feeding led to an increased f(H) (approximately 20 min(-1) irrespective of T(b)), but did not affect the rate of temperature change during heating or cooling. Therefore, it is likely that the increased blood flows during digestion are distributed exclusively to visceral organs and that the thermal conductance remains unaffected by the elevated metabolic rate during digestion.

Incidence of fetal bradycardia and effect of placental injury on fetal heart rate during second-trimester genetic amniocentesis.

PubMed

Hanprasertpong, T; Petpichetchian, C; Ponglopisit, S; Suksai, M; Kor-Anantakul, O; Geater, A; Pruksanusak, N; Hanprasertpong, J

2016-05-01

A prospective study was conducted for comparing the incidence of fetal bradycardia and level of fetal heart rate change following a second-trimester genetic amniocentesis with and without placental injury. A total of 257 and 495 participants in injured and non-injured groups were analysed. The incidence of fetal bradycardia following amniocentesis was not statistically different between the two groups (1.17%, [95% CI 0.24, 3.37] and 0.20%, [95% CI 0.005, 1.12]) in injured and non-injured placenta groups, respectively; p = 0.118). The mean change in baseline fetal heart rate before and after amniocentesis was also not significantly different between the two groups (p = 0.844). No fetal death or pregnancy loss occurred within 4 weeks after the procedure. All 4 bradycardia participants were normal and healthy and had an appropriate weight for their gestational age. We conclude that placental injury during a second-trimester genetic amniocentesis due to advanced maternal age poses only a low risk of fetal bradycardia, and there is no evidence of differences between subjects with injured and non-injured placenta in the changes in fetal heart rate.

Changes in Heart Rate and Autonomic Nervous Activity after Orthopedic Surgery in Elderly Japanese Patients

PubMed Central

TAN, CHIEKO; SAITO, NAO; MIYAWAKI, IKUKO

2016-01-01

Evidence regarding nursing support for delirium prevention is currently insufficient. An evaluation of changes in autonomic nervous activity over time after surgery would elucidate the features of autonomic nervous activity in patients with delirium. These results could provide a basis for effective nursing intervention and timing for preventing the onset of delirium. Here, we aimed to obtain basic data on effective nursing interventions for preventing the onset of postoperative delirium. Heart rate variability was recorded during the morning and nighttime on the day before surgery until 3 days postoperatively in elderly patients who underwent orthopedic surgery to investigate the manner in which heart rate and autonomic nervous activity changed over time. Data were collected over 11 months from July 2013 to November 2014. Surgical stress led to the maintenance of heart rate at a significantly higher value from the day of the surgery until postoperative day 3 compared to that before surgery. Moreover, the autonomic nervous activity remained unchanged during the morning, and it was significantly lower during the night from postoperative day 1 until postoperative day 3 than before the surgery. These results suggest that there is a decrease in parasympathetic nervous activity during the nighttime postoperatively. PMID:28289270

Can heart rate predict blood pressure response to anti-hypertensive drug therapy?

PubMed

Owens, P E; Lyons, S; O'Brien, E

1998-04-01

The use of heart rate in clinical practice is limited by its variability under measurement situations. The mean heart rate on ambulatory monitoring provides a more robust statistic for clinical use. We examined the relationship between mean heart rate on initial referral ambulatory blood pressure monitoring (ABPM) to the BP-lowering efficacy of the four main groups of anti-hypertensive medications, in a referral hypertensive population. Patients were retrospectively identified by review of the BP database, and data collected from the initial referral BP monitor off medication, and the subsequent ABPM after treatment with either beta-blockers, diuretics, calcium antagonists or angiotensin-converting enzyme (ACE) inhibitors. The change in mean arterial BP from the initial to the subsequent ABPM (ie, as a result of treatment) was correlated with the mean heart rate on the initial ABPM. A moderate association was found for initial daytime heart rate and BP response to beta-blockers (r = 0.24, P = 0.02), and ACE inhibitors (r = 0.14, P = 0.05). No such association was found for calcium antagonists or diuretics. When the groups were divided into those with a mean daytime heart rate <75 and > or =75 beats per min, BP reduction from beta-blocker and ACE inhibitor therapy was significantly greater in those patients with a higher daytime heart rate. We conclude that average daytime heart rate on pre-treatment ABPM can be useful as a predictor of BP response to beta-blockade or ACE inhibition.

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

PubMed

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

2013-01-01

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

The effect of low force chiropractic adjustments for 4 weeks on body surface electromagnetic field.

PubMed

Zhang, John; Snyder, Brian J

2005-01-01

To study the effects of 4 weeks of low-force chiropractic adjustments on body surface electromagnetic fields (EMFs). Thirty-five chiropractic students randomly assigned into control (17 subjects) and experimental groups (28 subjects). A triaxial fluxgate magnetometer was used for EMF detection. The subjects' body surface EMF was determined in the prone position before and after the chiropractic adjustment. A Toftness low-force chiropractic adjustment was applied to the cervical, thoracic, lumbar, and sacral areas as determined by the practitioner. Heart rate variability analysis was recorded once a week to determine autonomic nervous system activity in both the control and experimental groups. The EMF on the subjects' body surface decreased after chiropractic adjustment at the cervical, thoracic, lumbar, and sacral regions in all 6 visits during the 4-week treatment period. The EMF showed a downtrend over the 4-week period after the low-force adjustment. The same changes were not observed in the control group. The chiropractic adjustment group had a slight decrease in heart rate over the 4-week treatment period, and no significant change was observed in the control group. Heart rate variability analysis did not show consistent changes before and after the low-force adjustments during the treatment period. Low-force chiropractic adjustment in the cervical and thoracic areas resulted in a consistent reduction of the body surface EMF after 4 weeks of active treatment. No statistically significant differences were found in the heart rate and heart rate variability in the 4-week study.

Beat-by-beat analysis of cardiac output and blood pressure responses to short-term barostimulation in different body positions

NASA Astrophysics Data System (ADS)

Hildebrandt, Wulf; Schütze, Harald; Stegemann, J.

Rapid quantification of the human baro-reflex control of heart rate has been achieved on a beat-by-beat basis using a neck-chamber with quick ECG-triggered pressure changes. Referring to recent findings on heart rate and stroke volume, the present study uses this technique to compare cardiac output as well as blood pressure changes in supine and upright position to investigate feedback effects and to confirm postural reflex modifications not revealed by RR-interval changes. A suction profile starting at +40 mmHg and running 7 steps of pressure decrease down to -65 mmHg was examined in 0° and 90° tilting position while beat-by-beat recordings were done of heart rate, stroke volume (impedance-cardiography) and blood pressure (Finapres tm) (n=16). The percentual heart rate decrease failed to be significantly different between positions. A suction-induced stroke volume increase led to a cardiac output almost maintained when supine and significantly increased when upright. A decrease in all blood pressure values was found during suction, except for systolic values in upright position which increased. Conclusively, (a) it is confirmed that different inotropy accounts for the seen gravitational effect on the cardiac output not represented by heart rate; (b) identical suction levels in different positions lead to different stimuli at the carotid receptor. This interference has to be considered in microgravity studies by beat-by-beat measurement of cardiac output and blood pressure.

Changes in histopathology and tumor necrosis factor-α levels in the hearts of rats following asphyxial cardiac arrest.

PubMed

Lee, Jung Hoon; Lee, Tae-Kyeong; Kim, In Hye; Lee, Jae Chul; Won, Moo-Ho; Park, Joon Ha; Ahn, Ji Hyeon; Shin, Myoung Chul; Ohk, Taek Geun; Moon, Joong Bum; Cho, Jun Hwi; Park, Chan Woo; Tae, Hyun-Jin

2017-09-01

Post cardiac arrest (CA) syndrome is associated with a low survival rate in patients who initially have return of spontaneous circulation (ROSC) after CA. The aim of this study was to examine the histopathology and inflammatory response in the heart during the post CA syndrome. We induced asphyxial CA in male Sprague-Dawley rats and determined the survival rate of these rats during the post resuscitation phase. Survival of the rats decreased after CA: 66.7% at 6 hours, 36.7% at 1 day, and 6.7% at 2 days after ROSC following CA. The rats were sacrificed at 6 hours, 12 hours, 1 day, and 2 days after ROSC, and their heart tissues were examined. Histopathological scores increased at 12 hours post CA and afterwards, histopathological changes were not significant. In addition, levels of tumor necrosis factor-α immunoreactivity gradually increased after CA. The survival rate of rats 2 days post CA was very low, even though histopathological and inflammatory changes in the heart were not pronounced in the early stage following CA.

Heart Rate Variability: New Perspectives on Physiological Mechanisms, Assessment of Self-regulatory Capacity, and Health risk

PubMed Central

Shaffer, Fred

2015-01-01

Heart rate variability, the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operates on different time scales to adapt to environmental and psychological challenges. This article briefly reviews neural regulation of the heart and offers some new perspectives on mechanisms underlying the very low frequency rhythm of heart rate variability. Interpretation of heart rate variability rhythms in the context of health risk and physiological and psychological self-regulatory capacity assessment is discussed. The cardiovascular regulatory centers in the spinal cord and medulla integrate inputs from higher brain centers with afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. We also discuss the intrinsic cardiac nervous system and the heart-brain connection pathways, through which afferent information can influence activity in the subcortical, frontocortical, and motor cortex areas. In addition, the use of real-time HRV feedback to increase self-regulatory capacity is reviewed. We conclude that the heart's rhythms are characterized by both complexity and stability over longer time scales that reflect both physiological and psychological functional status of these internal self-regulatory systems. PMID:25694852

Heart Rate Variability: New Perspectives on Physiological Mechanisms, Assessment of Self-regulatory Capacity, and Health risk.

PubMed

McCraty, Rollin; Shaffer, Fred

2015-01-01

Heart rate variability, the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operates on different time scales to adapt to environmental and psychological challenges. This article briefly reviews neural regulation of the heart and offers some new perspectives on mechanisms underlying the very low frequency rhythm of heart rate variability. Interpretation of heart rate variability rhythms in the context of health risk and physiological and psychological self-regulatory capacity assessment is discussed. The cardiovascular regulatory centers in the spinal cord and medulla integrate inputs from higher brain centers with afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. We also discuss the intrinsic cardiac nervous system and the heart-brain connection pathways, through which afferent information can influence activity in the subcortical, frontocortical, and motor cortex areas. In addition, the use of real-time HRV feedback to increase self-regulatory capacity is reviewed. We conclude that the heart's rhythms are characterized by both complexity and stability over longer time scales that reflect both physiological and psychological functional status of these internal self-regulatory systems.

Can Monitoring Fetal Intestinal Inflammation Using Heart Rate Variability Analysis Signal Incipient Necrotizing Enterocolitis of the Neonate?

PubMed

Liu, Hai Lun; Garzoni, Luca; Herry, Christophe; Durosier, Lucien Daniel; Cao, Mingju; Burns, Patrick; Fecteau, Gilles; Desrochers, André; Patey, Natalie; Seely, Andrew J E; Faure, Christophe; Frasch, Martin G

2016-04-01

Necrotizing enterocolitis of the neonate is an acute inflammatory intestinal disease that can cause necrosis and sepsis. Chorioamnionitis is a risk factor of necrotizing enterocolitis. The gut represents the biggest vagus-innervated organ. Vagal activity can be measured via fetal heart rate variability. We hypothesized that fetal heart rate variability can detect fetuses with incipient gut inflammation. Prospective animal study. University research laboratory. Chronically instrumented near-term fetal sheep (n = 21). Animals were surgically instrumented with vascular catheters and electrocardiogram to allow manipulation and recording from nonanesthetized animals. In 14 fetal sheep, inflammation was induced with lipopolysaccharide (IV) to mimic chorioamnionitis. Fetal arterial blood samples were drawn at selected time points over 54 hours post lipopolysaccharide for blood gas and cytokines (interleukin-6 and tumor necrosis factor-α enzymelinked immunosorbent assay). Fetal heart rateV was quantified throughout the experiment. The time-matched fetal heart rate variability measures were correlated to the levels of interleukin-6 and tumor necrosis factor-α. Upon necropsy, ionized calcium binding adaptor molecule 1+ (Iba1+), CD11c+ (M1), CD206+ (M2 macrophages), and occludin (leakiness marker) immunofluorescence in the terminal ileum was quantified along with regional Iba1+ signal in the brain (microglia). Interleukin-6 peaked at 3 hours post lipopolysaccharide accompanied by mild cardiovascular signs of sepsis. At 54 hours, we identified an increase in Iba1+ and, specifically, M1 macrophages in the ileum accompanied by increased leakiness, with no change in Iba1 signal in the brain. Preceding this change on tissue level, at 24 hours, a subset of nine fetal heart rate variability measures correlated exclusively to the Iba+ markers of ileal, but not brain, inflammation. An additional fetal heart rate variability measure, mean of the differences of R-R intervals, correlated uniquely to M1 ileum macrophages increasing due to lipopolysaccharide. We identified a unique subset of fetal heart rate variability measures reflecting 1.5 days ahead of time the levels of macrophage activation and increased leakiness in terminal ileum. We propose that such subset of fetal heart rate variability measures reflects brain-gut communication via the vagus nerve. Detecting such noninvasively obtainable organ-specific fetal heart rate variability signature of inflammation would alarm neonatologists about neonates at risk of developing necrotizing enterocolitis and sepsis. Clinical validation studies are required.

Relation between heart beat fluctuations and cyclic alternating pattern during sleep in insomnia patients.

PubMed

de Leon-Lomeli, R; Murguia, J S; Chouvarda, I; Mendez, M O; Gonzalez-Galvan, E; Alba, A; Milioli, G; Grassi, A; Terzano, M G; Parrino, L

2014-01-01

Insomnia is a condition that affects the nervous and muscular system. Thirty percent of the population between 18 and 60 years suffers from insomnia. The effects of this disorder involve problems such as poor school or job performance and traffic accidents. In addition, patients with insomnia present changes in the cardiac function during sleep. Furthermore, the structure of electroencephalographic A-phases, which builds up the Cyclic Alternating Pattern during sleep, is related to the insomnia events. Therefore, the relationship between these brain activations (A-phases) and the autonomic nervous system would be of interest, revealing the interplay of central and autonomic activity during insomnia. With this goal, a study of the relationship between A-phases and heart rate fluctuations is presented. Polysomnography recording of five healthy subjects, five sleep misperception patients and five patients with psychophysiological insomnia were used in the study. Detrended Fluctuation Analysis (DFA) was used in order to evaluate the heart rate dynamics and this was correlated with the number of A-phases. The results suggest that pathological patients present changes in the dynamics of the heart rate. This is reflected in the modification of A-phases dynamics, which seems to modify of heart rate dynamics.

Effect of Temperature on Heart Rate Variability in Neonatal ICU Patients With Hypoxic-Ischemic Encephalopathy.

PubMed

Massaro, An N; Campbell, Heather E; Metzler, Marina; Al-Shargabi, Tareq; Wang, Yunfei; du Plessis, Adre; Govindan, Rathinaswamy B

2017-04-01

To determine whether measures of heart rate variability are related to changes in temperature during rewarming after therapeutic hypothermia for hypoxic-ischemic encephalopathy. Prospective observational study. Level 4 neonatal ICU in a free-standing academic children's hospital. Forty-four infants with moderate to severe hypoxic-ischemic encephalopathy treated with therapeutic hypothermia. Continuous electrocardiogram data from 2 hours prior to rewarming through 2 hours after completion of rewarming (up to 10 hr) were analyzed. Median beat-to-beat interval and measures of heart rate variability were quantified including beat-to-beat interval SD, low and high frequency relative spectral power, detrended fluctuation analysis short and long α exponents (αS and αL), and root mean square short and long time scales. The relationships between heart rate variability measures and esophageal/axillary temperatures were evaluated. Heart rate variability measures low frequency, αS, and root mean square short and long time scales were negatively associated, whereas αL was positively associated, with temperature (p < 0.01). These findings signify an overall decrease in heart rate variability as temperature increased toward normothermia. Measures of heart rate variability are temperature dependent in the range of therapeutic hypothermia to normothermia. Core body temperature needs to be considered when evaluating heart rate variability metrics as potential physiologic biomarkers of illness severity in hypoxic-ischemic encephalopathy infants undergoing therapeutic hypothermia.

Investigation of the Effect of Occupational Noise Exposure on Blood Pressure and Heart Rate of Steel Industry Workers

PubMed Central

Zamanian, Zahra; Rostami, Reza; Hasanzadeh, Jafar; Hashemi, Hassan

2013-01-01

Background and Objectives. This study aimed to investigate the effect of noise exposure on blood pressure and heart rate of steel industry workers. Materials and Methods. In the present cross-sectional study, 50 workers were selected from a steel company in Fars province, Iran, and exposed to 85, 95, and 105 dB noise levels for 5 minutes. The participants' blood pressure and heart rate were measured using Beurer BC16 pulse meter both before and after the exposure. Results. The study results showed no significant difference in blood pressure and heart rate before and after the exposure. However, the workers' systolic blood pressure had increased compared to before the exposure; of course, the difference was not statistically significant (P > 0.05). Besides, although the subjects' heart rate had reduced in comparison to before the exposure, the difference was not statistically significant (P > 0.05). Conclusion. No significant change was observed in blood pressure and heart rate after acute exposure to 85, 95, and 105 dB noise levels. PMID:23781252

Post-exercise contractility, diastolic function, and pressure: Operator-independent sensor-based intelligent monitoring for heart failure telemedicine

PubMed Central

Bombardini, Tonino; Gemignani, Vincenzo; Bianchini, Elisabetta; Pasanisi, Emilio; Pratali, Lorenza; Pianelli, Mascia; Faita, Francesco; Giannoni, Massimo; Arpesella, Giorgio; Sicari, Rosa; Picano, Eugenio

2009-01-01

Background New sensors for intelligent remote monitoring of the heart should be developed. Recently, a cutaneous force-frequency relation recording system has been validated based on heart sound amplitude and timing variations at increasing heart rates. Aim To assess sensor-based post-exercise contractility, diastolic function and pressure in normal and diseased hearts as a model of a wireless telemedicine system. Methods We enrolled 150 patients and 22 controls referred for exercise-stress echocardiography, age 55 ± 18 years. The sensor was attached in the precordial region by an ECG electrode. Stress and recovery contractility were derived by first heart sound amplitude vibration changes; diastolic times were acquired continuously. Systemic pressure changes were quantitatively documented by second heart sound recording. Results Interpretable sensor recordings were obtained in all patients (feasibility = 100%). Post-exercise contractility overshoot (defined as increase > 10% of recovery contractility vs exercise value) was more frequent in patients than controls (27% vs 8%, p < 0.05). At 100 bpm stress heart rate, systolic/diastolic time ratio (normal, < 1) was > 1 in 20 patients and in none of the controls (p < 0.01); at recovery systolic/diastolic ratio was > 1 in only 3 patients (p < 0.01 vs stress). Post-exercise reduced arterial pressure was sensed. Conclusion Post-exercise contractility, diastolic time and pressure changes can be continuously measured by a cutaneous sensor. Heart disease affects not only exercise systolic performance, but also post-exercise recovery, diastolic time intervals and blood pressure changes – in our study, all of these were monitored by a non-invasive wearable sensor. PMID:19442285

Effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in type 2 diabetes mellitus patients.

PubMed

Kang, Seol-Jung; Ko, Kwang-Jun; Baek, Un-Hyo

2016-07-01

[Purpose] This study evaluated the effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in patients with Type 2 diabetes mellitus. [Subjects and Methods] The subjects were 16 female patients with Type 2 diabetes mellitus selected among the participants of a chronic disease management exercise class at C Region Public Health Center in South Korea. Subjects were randomly assigned to the exercise group (n=8; age, 55.97 ± 7.37) or the control group (n=8; age, 57.53 ± 4.63) The exercise group performed aerobic and resistance exercises for 60 minutes per day, 3 times per week for 12 weeks. Anthropometric measurements, biochemical markers, physical fitness, and heart rate variability were examined. [Results] After 12 weeks of exercise, weight, body fat percentage, waist circumference, blood glucose, insulin resistance, glycated hemoglobin level, systolic blood pressure, and diastolic blood pressure significantly decreased and cardiorespiratory fitness and muscular strength significantly increased in the exercise group. Although heart rate variability measures showed favorable changes with the exercise program, none were significant. [Conclusion] Although the exercise program did not show notable changes in heart rate variability in patients with Type 2 diabetes within the timeframe of the study, exercise may contribute to the prevention and control of cardiovascular autonomic neuropathy.

Physiological responses to the Coriolis illusion: effects of head position and vision.

PubMed

Westmoreland, David; Krell, Robert W; Self, Brian P

2007-10-01

Changes in sympathetic outflow during Type II spatial disorientation are well documented. In this study we investigated the influences of head position and eye state (open or closed) on sympathetic activation. There were 11 naive subjects (6 men, 5 women) who were tested in a General Aviation Trainer that accelerated at a subthreshold rate for 60 s until a constant angular velocity of 90 degrees x s(-1) was reached. Approximately 40 s later, subjects were instructed to tilt their heads along either the pitch or roll axis, stimulating a Coriolis illusion. Subjects reported the perceived intensity and duration of disorientation. Heart rate, heart rate variability, and electrodermal responses were recorded before, during, and after the period of disorientation. Each subject completed four trials, which were crossed combinations of head position and eye state. There were significant increases in heart rate and the electrodermal response during disorientation, but no significant change in heart rate variability. Head position had no significant effect on any physiological parameters or on the perceived intensity of disorientation; subjects reported a shorter duration of disorientation when the head was tilted into the roll versus the pitch axis. Eye state had no effect on heart rate, heart rate variability, or the intensity of disorientation, but the electrodermal response was somewhat greater, and the duration of disorientation shorter when eyes were open. The results suggest that head position and eye state (open or closed) do not need to be included as factors when investigating sympathetic outflow during a mild Coriolis illusion.

[Current status and recommendations for intrapartum monitoring of fetal heart rate].

PubMed

Měchurová, A; Velebil, P; Hruban, L; Janků, P

2016-04-01

Monitoring of fetal heart rate is one of the basic components of obstetrical care, in which the cardiotocography remains the gold standard and screening method in early diagnosis of fetal hypoxia, even after introduction of other selective methods of intrauterine monitoring of fetal well-being. The review article is divided into several parts: pathophysiology of fetal oxygenation, fetal heart rate and changes of fetal hemodynamics, and rules for fetal heart rate auscultation. The main principles of cardiotocographic monitoring and evaluation of ante- and intrapartrum recordings according to the FIGO criteria from 1986 and evaluation of intrapartum recordings according to the 2015 FIGO recommendations are mentioned. At the end a comparative table of 1986 FIGO and 2015 FIGO criteria is presented. Review.

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.

[Effect of Music Intervention on Maternal Anxiety and Fetal Heart Rate Pattern During Non-Stress Test].

PubMed

Oh, Myung Ok; Kim, Young Jeoum; Baek, Cho Hee; Kim, Ju Hee; Park, No Mi; Yu, Mi Jeong; Song, Han Sol

2016-06-01

The purpose of this cross-over experimental study was to examine effects of music intervention on maternal anxiety, fetal heart rate pattern and testing time during non-stress tests (NST) for antenatal fetal assessment. Sixty pregnant women within 28 to 40 gestational weeks were randomly assigned to either the experimental group (n=30) or control group (n=30). Music intervention was provided to pregnant women in the experimental group during NST. Degree of maternal anxiety and fetal heart rate pattern were our primary outcomes. State-trait anxiety inventory, blood pressure, pulse rate, and changes in peripheral skin temperature were assessed to determine the degree of maternal anxiety. Baseline fetal heart rate, frequency of acceleration in fetal heart rate, fetal movement test and testing time for reactive NST were assessed to measure the fetal heart rate pattern. The experimental group showed significantly lower scores in state anxiety than the control group. There were no significant differences in systolic blood pressure and pulse rate between the two groups. Baseline fetal heart rate was significantly lower in the experimental group than in the control group. Frequency of acceleration in fetal heart rate was significantly increased in the experimental group compared to the control group. There were no significant differences in fetal movement and testing time for reactive NST between the two groups. Present results suggest that music intervention could be an effective nursing intervention for alel viating anxiety during non-stress test.

Energy expenditure in frontotemporal dementia: a behavioural and imaging study.

PubMed

Ahmed, Rebekah M; Landin-Romero, Ramon; Collet, Tinh-Hai; van der Klaauw, Agatha A; Devenney, Emma; Henning, Elana; Kiernan, Matthew C; Piguet, Olivier; Farooqi, I Sadaf; Hodges, John R

2017-01-01

SEE FINGER DOI101093/AWW312 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Abnormal eating behaviour and metabolic parameters including insulin resistance, dyslipidaemia and body mass index are increasingly recognized as important components of neurodegenerative disease and may contribute to survival. It has previously been established that behavioural variant frontotemporal dementia is associated with abnormal eating behaviour characterized by increased sweet preference. In this study, it was hypothesized that behavioural variant frontotemporal dementia might also be associated with altered energy expenditure. A cohort of 19 patients with behavioural variant frontotemporal dementia, 13 with Alzheimer's disease and 16 (age- and sex-matched) healthy control subjects were studied using Actiheart devices (CamNtech) to assess resting and stressed heart rate. Actiheart devices were fitted for 7 days to measure sleeping heart rate, activity levels, and resting, active and total energy expenditure. Using high resolution structural magnetic resonance imaging the neural correlates of increased resting heart rate were investigated including cortical thickness and region of interest analyses. In behavioural variant frontotemporal dementia, resting (P = 0.001), stressed (P = 0.037) and sleeping heart rate (P = 0.038) were increased compared to control subjects, and resting heart rate (P = 0.020) compared to Alzheimer disease patients. Behavioural variant frontotemporal dementia was associated with decreased activity levels compared to controls (P = 0.002) and increased resting energy expenditure (P = 0.045) and total energy expenditure (P = 0.035). Increased resting heart rate correlated with behavioural (Cambridge Behavioural Inventory) and cognitive measures (Addenbrooke's Cognitive Examination). Increased resting heart rate in behavioural variant frontotemporal dementia correlated with atrophy involving the mesial temporal cortex, insula, and amygdala, regions previously suggested to be involved exclusively in social and emotion processing in frontotemporal dementia. These neural correlates overlap the network involved in eating behaviour in frontotemporal dementia, suggesting a complex interaction between eating behaviour, autonomic function and energy homeostasis. As such the present study suggests that increased heart rate and autonomic changes are prevalent in behavioural variant frontotemporal dementia, and are associated with changes in energy expenditure. An understanding of these changes and neural correlates may have potential relevance to disease progression and prognosis. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Monitoring training status with HR measures: do all roads lead to Rome?

PubMed Central

Buchheit, Martin

2014-01-01

Measures of resting, exercise, and recovery heart rate are receiving increasing interest for monitoring fatigue, fitness and endurance performance responses, which has direct implications for adjusting training load (1) daily during specific training blocks and (2) throughout the competitive season. However, these measures are still not widely implemented to monitor athletes' responses to training load, probably because of apparent contradictory findings in the literature. In this review I contend that most of the contradictory findings are related to methodological inconsistencies and/or misinterpretation of the data rather than to limitations of heart rate measures to accurately inform on training status. I also provide evidence that measures derived from 5-min (almost daily) recordings of resting (indices capturing beat-to-beat changes in heart rate, reflecting cardiac parasympathetic activity) and submaximal exercise (30- to 60-s average) heart rate are likely the most useful monitoring tools. For appropriate interpretation at the individual level, changes in a given measure should be interpreted by taking into account the error of measurement and the smallest important change of the measure, as well as the training context (training phase, load, and intensity distribution). The decision to use a given measure should be based upon the level of information that is required by the athlete, the marker's sensitivity to changes in training status and the practical constrains required for the measurements. However, measures of heart rate cannot inform on all aspects of wellness, fatigue, and performance, so their use in combination with daily training logs, psychometric questionnaires and non-invasive, cost-effective performance tests such as a countermovement jump may offer a complete solution to monitor training status in athletes participating in aerobic-oriented sports. PMID:24578692

Cardiac myofibrillar contractile properties during the progression from hypertension to decompensated heart failure.

PubMed

Hanft, Laurin M; Emter, Craig A; McDonald, Kerry S

2017-07-01

Heart failure arises, in part, from a constellation of changes in cardiac myocytes including remodeling, energetics, Ca 2+ handling, and myofibrillar function. However, little is known about the changes in myofibrillar contractile properties during the progression from hypertension to decompensated heart failure. The aim of the present study was to provide a comprehensive assessment of myofibrillar functional properties from health to heart disease. A rodent model of uncontrolled hypertension was used to test the hypothesis that myocytes in compensated hearts exhibit increased force, higher rates of force development, faster loaded shortening, and greater power output; however, with progression to overt heart failure, we predicted marked depression in these contractile properties. We assessed contractile properties in skinned cardiac myocyte preparations from left ventricles of Wistar-Kyoto control rats and spontaneous hypertensive heart failure (SHHF) rats at ~3, ~12, and >20 mo of age to evaluate the time course of myofilament properties associated with normal aging processes compared with myofilaments from rats with a predisposition to heart failure. In control rats, the myofilament contractile properties were virtually unchanged throughout the aging process. Conversely, in SHHF rats, the rate of force development, loaded shortening velocity, and power all increased at ~12 mo and then significantly fell at the >20-mo time point, which coincided with a decrease in left ventricular fractional shortening. Furthermore, these changes occurred independent of changes in β-myosin heavy chain but were associated with depressed phosphorylation of myofibrillar proteins, and the fall in loaded shortening and peak power output corresponded with the onset of clinical signs of heart failure. NEW & NOTEWORTHY This novel study systematically examined the power-generating capacity of cardiac myofilaments during the progression from hypertension to heart disease. Previously undiscovered changes in myofibrillar power output were found and were associated with alterations in myofilament proteins, providing potential new targets to exploit for improved ventricular pump function in heart failure. Copyright © 2017 the American Physiological Society.

Deriving temperature and age appropriate heart rate centiles for children with acute infections.

PubMed

Thompson, M; Harnden, A; Perera, R; Mayon-White, R; Smith, L; McLeod, D; Mant, D

2009-05-01

To describe the reference range for heart rate in children aged 3 months-10 years presenting to primary care with self-limiting infections. Cross-sectional study of children presenting to primary care with suspected acute infection. Heart rate was measured using a pulse oximeter and axillary temperature using an electronic thermometer. Centile charts of heart rates expected at given temperatures for children with self-limiting infections were calculated. Ten general practice surgeries and two out-of-hours centres in England. 1933 children presenting with suspected acute infections were recruited from in-hours general practice surgeries (1050 or 54.3%) or out-of-hours centres (883 or 45.7%). After excluding children who subsequently attended hospital and those without a final diagnosis of acute infection, 1589 children were used to create the centile charts of whom (859 or 54.1%) had upper respiratory tract infections and (215 or 13.5%) non-specific viral illness. Median, 75th, 90th and 97th centiles of heart rate at each temperature level. Heart rate increased by 9.9-14.1 bpm with each 1 degrees C increment in temperature. The 50th, 75th, 90th and 97th centiles of heart rate at each temperature level are presented graphically. Age-specific centile charts of heart rates expected at different temperatures should be used by clinicians in the initial assessment of children with acute infections. The charts will identify children who have a heart rate higher than expected for a given temperature and facilitate the interpretation of changes in heart rate on reassessment. Further research on the predictive value of the centile charts is needed to optimise their diagnostic utility.

[Detection of Heart Rate of Fetal ECG Based on STFT and BSS].

PubMed

Wang, Xu; Cai, Kun

2016-01-01

Changes in heart rate of fetal is function regulating performance of the circulatory system and the central nervous system, it is significant to detect heart rate of fetus in perinatal fetal. This paper puts forward the fetal heart rate detection method based on short time Fourier transform and blind source separation. First of all, the mixed ECG signal was preprocessed, and then the wavelet transform technique was used to separate the fetal ECG signal with noise from mixed ECG signal, after that, the short-time Fourier transform and the blind separation were carried on it, and then calculated the correlation coefficient of it, Finally, An independent component that it has strongest correlation with the original signal was selected to make FECG peak detection and calculated the fetal instantaneous heart rate. The experimental results show that the method can improve the detection rate of the FECG peak (R), and it has high accuracy in fixing peak(R) location in the case of low signal-noise ratio.

Autonomic changes after treatment of agoraphobia with panic attacks.

PubMed

Roth, W T; Telch, M J; Taylor, C B; Agras, W S

1988-04-01

Twenty-three patients meeting DSM-III criteria for agoraphobia with panic attacks and 14 age-, race-, and sex-matched nonanxious controls were tested in the laboratory and on a test walk in a shopping mall. The patients were tested before and after about 15 weeks of treatment with placebo and exposure therapy, imipramine and exposure therapy, or imipramine and initial antiexposure instructions. Controls were tested twice at a similar interval, but without any treatment. On test day 1, patients compared to controls showed higher average heart rate and skin conductance levels and greater numbers of skin conductance fluctuations in the laboratory, and higher heart rates before and during the test walk. Between pretreatment and posttreatment tests, clinical ratings improved and skin conductance levels decreased in all treatment groups. Heart rate levels in the laboratory, on the other hand, decreased in patients on placebo and rose in patients on imipramine. Thus, imipramine compromises the usefulness of heart rate as a measure of emotional arousal. Higher pretreatment heart rates predicted greater clinical improvement.

The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia.

PubMed

Duck Shin, Young; Hoon Yim, Kyoung; Hi Park, Sang; Wook Jeon, Yong; Ho Bae, Jin; Soo Lee, Tae; Hwan Kim, Myoung; Jin Choi, Young

2014-03-01

The use of an esophageal stethoscope is a basic heart sounds monitoring procedure performed in patients under general anesthesia. As the size of the first heart sound can express the left ventricle function, its correlation with cardiac output should be investigated. The aim of this study was to investigate the effects of cardiac output (CO) on the first heart sound (S1) amplitude. Methods : Six male beagles were chosen. The S1 was obtained with the newly developed esophageal stethoscope system. CO was measured using NICOM, a non-invasive CO measuring device. Ephedrine and beta blockers were administered to the subjects to compare changes in figures, and the change from using an inhalation anesthetic was also compared. The S1 amplitude displayed positive correlation with the change rate of CO (r = 0.935, p < 0.001). The heart rate measured using the esophageal stethoscope and ECG showed considerably close figures through the Bland-Altman plot and showed a high positive correlation (r = 0.988, p < 0,001). In beagles, the amplitude of S1 had a significant correlation with changes in CO in a variety of situations.

Aging reduces complexity of heart rate variability assessed by conditional entropy and symbolic analysis.

PubMed

Takahashi, Anielle C M; Porta, Alberto; Melo, Ruth C; Quitério, Robison J; da Silva, Ester; Borghi-Silva, Audrey; Tobaldini, Eleonora; Montano, Nicola; Catai, Aparecida M

2012-06-01

Increasing age is associated with a reduction in overall heart rate variability as well as changes in complexity of physiologic dynamics. The aim of this study was to verify if the alterations in autonomic modulation of heart rate caused by the aging process could be detected by Shannon entropy (SE), conditional entropy (CE) and symbolic analysis (SA). Complexity analysis was carried out in 44 healthy subjects divided into two groups: old (n = 23, 63 ± 3 years) and young group (n = 21, 23 ± 2). It was analyzed SE, CE [complexity index (CI) and normalized CI (NCI)] and SA (0V, 1V, 2LV and 2ULV patterns) during short heart period series (200 cardiac beats) derived from ECG recordings during 15 min of rest in a supine position. The sequences characterized by three heart periods with no significant variations (0V), and that with two significant unlike variations (2ULV) reflect changes in sympathetic and vagal modulation, respectively. The unpaired t test (or Mann-Whitney rank sum test when appropriate) was used in the statistical analysis. In the aging process, the distributions of patterns (SE) remain similar to young subjects. However, the regularity is significantly different; the patterns are more repetitive in the old group (a decrease of CI and NCI). The amounts of pattern types are different: 0V is increased and 2LV and 2ULV are reduced in the old group. These differences indicate marked change of autonomic regulation. The CE and SA are feasible techniques to detect alteration in autonomic control of heart rate in the old group.

Effects of changes in vertical occlusal dimension on heart rate fluctuations in guinea pigs.

PubMed

Taga, Hitoshi; Azuma, Yukio; Maehara, Kiyoshi; Nomura, Shuichi

2012-01-01

We have previously reported that the decrease of the vertical occlusal dimension (VOD) led to heart failure and abnormalities in creatine phosphokinase (CPK) in guinea pigs. In the present study, we investigated the autonomic activity and the origin of the abnormality in CPK under different occlusal conditions. Guinea pigs were separated into the following five groups: untreated control, reduced VOD, slit, restored VOD and increased VOD groups and compared for their electrocardiogram and heart rate fluctuations for two weeks using Fluclet, computer software. The control group revealed no changes in heart rate fluctuations or posture. The reduced VOD group exhibited a two-phase wave of heart rate fluctuations, with the first peak 0-2 days after teeth grinding, and the second peak starting from 4 days after teeth grinding until sudden death (usually 12th day), accompanied by head drop. The slit and the restored VOD groups exhibited only the first peak. The increased VOD group, with approximately 3 mm-thick acrylic pellets bonded to the posterior teeth, showed no heart rate fluctuations. Body weight loss was most prominent in the reduced VOD group, and became much milder in the order of increased VOD, restored and slit groups. The reduced VOD group exhibited transient elevation of skeletal muscle type of CPK isozyme activity within two days after treatment. The present study suggests that the first peak of heart rate fluctuations is caused by pulpal stimulation, and the second peak by excessive contraction (excessive excitation of the motor output system and the autonomic nervous system) of the masticatory muscles. On the other hand, increased VOD did not influence either the motor or the autonomic nervous system.

Cardiovascular responses to postural changes: differences with age for women and men

NASA Technical Reports Server (NTRS)

Frey, M. A.; Tomaselli, C. M.; Hoffler, W. G.

1994-01-01

The cardiovascular responses to postural change, and how they are affected by aging, are inadequately described in women. Therefore, the authors examined the influence of age and sex on the responses of blood pressure, cardiac output, heart rate, and other variables to change in posture. Measurements were made after 10 minutes each in the supine, seated, and standing positions in 22 men and 25 women who ranged in age from 21 to 59 years. Several variables differed, both by sex and by age, when subjects were supine. On rising, subjects' diastolic and mean arterial pressures, heart rate, total peripheral resistance (TPR), and thoracic impedance increased; cardiac output, stroke volume, and mean stroke ejection rate decreased; and changes in all variables, except heart rate, were greater from supine to sitting than sitting to standing. The increase in heart rate was greater in the younger subjects, and increases in TPR and thoracic impedance were greater in the older subjects. Stroke volume decreased less, and TPR and thoracic impedance increased more, in the women than in the men. The increase in TPR was particularly pronounced in the older women. These studies show that the cardiovascular responses to standing differ, in some respects, between the sexes and with age. The authors suggest that the sex differences are, in part, related to greater decrease of thoracic blood volume with standing in women than in men, and that the age differences result, in part, from decreased responsiveness of the high-pressure baroreceptor system.

Idiosyncratic heart rate response in men during sexual arousal.

PubMed

Rowland, David L; Crawford, Sara B

2011-05-01

Heart rate, sensitive to sympathetic activation, is known to change during sexual arousal and therefore may be a useful tool for investigating psychosomatic differences between sexually functional and dysfunctional men. However, heart rate during arousal also tends to be highly variable across individual men, making its predictability based on group patterns relatively poor. We wanted to determine whether individual men show idiosyncratic heart rate patterns during sexual arousal, that is, whether they exhibit consistent patterns across similar (though not identical) stimulus situations. Agreement between heart rates under the two conditions, visual sexual stimulation (VSS) and VSS + vibrotactile (VIB), was assessed using the concordance correlation coefficient (CCC).   Thirty-eight men, 25 of whom were diagnosed with premature ejaculation (PE), were monitored for penile response and heart rate under two similar (though not identical) conditions: a 9-minute erotic video (VSS), then a 9-minute erotic video combined with vibrotactile penile stimulation (VSS + VIB). CCC for men with PE was 0.65; for the sexually functional comparison group, CCC was 0.82. For both groups combined, CCC was 0.71. For all groupings, the CCC was relatively high, indicating agreement in heart rate from one session to the next within individual men. Despite high intersubject variation in heart rate patterns, individual men show signature heart rates across similar sexual stimulus sessions. Such stereotypy helps explain previous inconsistent findings and may also serve as a marker for the effectiveness of treatments designed to improve ejaculatory control in men with PE. © 2011 International Society for Sexual Medicine.

Estimating energy expenditure from heart rate in older adults: a case for calibration.

PubMed

Schrack, Jennifer A; Zipunnikov, Vadim; Goldsmith, Jeff; Bandeen-Roche, Karen; Crainiceanu, Ciprian M; Ferrucci, Luigi

2014-01-01

Accurate measurement of free-living energy expenditure is vital to understanding changes in energy metabolism with aging. The efficacy of heart rate as a surrogate for energy expenditure is rooted in the assumption of a linear function between heart rate and energy expenditure, but its validity and reliability in older adults remains unclear. To assess the validity and reliability of the linear function between heart rate and energy expenditure in older adults using different levels of calibration. Heart rate and energy expenditure were assessed across five levels of exertion in 290 adults participating in the Baltimore Longitudinal Study of Aging. Correlation and random effects regression analyses assessed the linearity of the relationship between heart rate and energy expenditure and cross-validation models assessed predictive performance. Heart rate and energy expenditure were highly correlated (r=0.98) and linear regardless of age or sex. Intra-person variability was low but inter-person variability was high, with substantial heterogeneity of the random intercept (s.d. =0.372) despite similar slopes. Cross-validation models indicated individual calibration data substantially improves accuracy predictions of energy expenditure from heart rate, reducing the potential for considerable measurement bias. Although using five calibration measures provided the greatest reduction in the standard deviation of prediction errors (1.08 kcals/min), substantial improvement was also noted with two (0.75 kcals/min). These findings indicate standard regression equations may be used to make population-level inferences when estimating energy expenditure from heart rate in older adults but caution should be exercised when making inferences at the individual level without proper calibration.

The phylogeny and ontogeny of autonomic control of the heart and cardiorespiratory interactions in vertebrates.

PubMed

Taylor, Edwin W; Leite, Cleo A C; Sartori, Marina R; Wang, Tobias; Abe, Augusto S; Crossley, Dane A

2014-03-01

Heart rate in vertebrates is controlled by activity in the autonomic nervous system. In spontaneously active or experimentally prepared animals, inhibitory parasympathetic control is predominant and is responsible for instantaneous changes in heart rate, such as occur at the first air breath following a period of apnoea in discontinuous breathers like inactive reptiles or species that surface to air breathe after a period of submersion. Parasympathetic control, exerted via fast-conducting, myelinated efferent fibres in the vagus nerve, is also responsible for beat-to-beat changes in heart rate such as the high frequency components observed in spectral analysis of heart rate variability. These include respiratory modulation of the heartbeat that can generate cardiorespiratory synchrony in fish and respiratory sinus arrhythmia in mammals. Both may increase the effectiveness of respiratory gas exchange. Although the central interactions generating respiratory modulation of the heartbeat seem to be highly conserved through vertebrate phylogeny, they are different in kind and location, and in most species are as yet little understood. The heart in vertebrate embryos possesses both muscarinic cholinergic and β-adrenergic receptors very early in development. Adrenergic control by circulating catecholamines seems important throughout development. However, innervation of the cardiac receptors is delayed and first evidence of a functional cholinergic tonus on the heart, exerted via the vagus nerve, is often seen shortly before or immediately after hatching or birth, suggesting that it may be coordinated with the onset of central respiratory rhythmicity and subsequent breathing.

Effect of heart rate on the hemodynamics of bileaflet mechanical heart valves' prostheses (St. Jude Medical) in the aortic position and in the opening phase: A computational study.

PubMed

Jahandardoost, Mehdi; Fradet, Guy; Mohammadi, Hadi

2016-03-01

To date, to the best of the authors' knowledge, in almost all of the studies performed around the hemodynamics of bileaflet mechanical heart valves, a heart rate of 70-72 beats/min has been considered. In fact, the heart rate of ~72 beats/min does not represent the entire normal physiological conditions under which the aortic or prosthetic valves function. The heart rates of 120 or 50 beats/min may lead to hemodynamic complications, such as plaque formation and/or thromboembolism in patients. In this study, the hemodynamic performance of the bileaflet mechanical heart valves in a wide range of normal and physiological heart rates, that is, 60-150 beats/min, was studied in the opening phase. The model considered in this study was a St. Jude Medical bileaflet mechanical heart valve with the inner diameter of 27 mm in the aortic position. The hemodynamics of the native valve and the St. Jude Medical valve were studied in a variety of heart rates in the opening phase and the results were carefully compared. The results indicate that peak values of the velocity profile downstream of the valve increase as heart rate increases, as well as the location of the maximum velocity changes with heart rate in the St. Jude Medical valve model. Also, the maximum values of shear stress and wall shear stresses downstream of the valve are proportional to heart rate in both models. Interestingly, the maximum shear stress and wall shear stress values in both models are in the same range when heart rate is <90 beats/min; however, these values significantly increase in the St. Jude Medical valve model when heart rate is >90 beats/min (up to ~40% growth compared to that of the native valve). The findings of this study may be of importance in the hemodynamic performance of bileaflet mechanical heart valves. They may also play an important role in design improvement of conventional prosthetic heart valves and the design of the next generation of prosthetic valves, such as percutaneous valves. © IMechE 2016.

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…

Using time-series intervention analysis to model cow heart rate affected by programmed audio and environmental/physiological

USDA-ARS?s Scientific Manuscript database

This research is the first use of the Box-Jenkins time-series models to describe changes in heart rate (HR) of free-ranging crossbred cows (Bos taurus) receiving both programmed audio cues from directional virtual fencing (DVFTM) devices and non-programmed environmental/physiological cues. The DVFT...

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.

Monitoring stage fright outside the laboratory: an example in a professional musician using wearable sensors.

PubMed

Kusserow, Martin; Candia, Victor; Amft, Oliver; Hildebrandt, Horst; Folkers, Gerd; Tröster, Gerhard

2012-03-01

We implemented and tested a wearable sensor system to measure patterns of stress responses in a professional musician under public performance conditions. Using this sensor system, we monitored the cellist's heart activity, the motion of multiple body parts, and their gradual changes during three repeated performances of a skill-demanding piece in front of a professional audience. From the cellist and her teachers, we collected stage fright self-reports and performance ratings that were related to our sensor data analysis results. Concomitant to changes in body motion and heart rate, the cellist perceived a reduction in stage fright. Performance quality was objectively improved, as technical playing errors decreased throughout repeated renditions. In particular, from performance 1 to 3, the wearable sensors measured a significant increase in the cellist's bowing motion dynamics of approximately 6% and a decrease in heart rate. Bowing motion showed a marginal correlation to the observed heart rate patterns during playing. The wearable system did not interfere with the cellist's performance, thereby allowing investigation of stress responses during natural public performances.

Cardiorespiratory adaptation to breath-holding in air: Analysis via a cardiopulmonary simulation model.

PubMed

Albanese, Antonio; Limei Cheng; Ursino, Mauro; Chbat, Nicolas W

2015-01-01

Apnea via breath-holding (BH) in air induces cardiorespiratory adaptation that involves the activation of several reflex mechanisms and their complex interactions. Hence, the effects of BH in air on cardiorespiratory function can become hardly predictable and difficult to be interpreted. Particularly, the effect on heart rate is not yet completely understood because of the contradicting results of different physiological studies. In this paper we apply our previously developed cardiopulmonary model (CP Model) to a scenario of BH with a twofold intent: (1) further validating the CP Model via comparison against experimental data; (2) gaining insights into the physiological reasoning for such contradicting experimental results. Model predictions agreed with published experimental animal and human data and indicated that heart rate increases during BH in air. Changes in the balance between sympathetic and vagal effects on heart rate within the model proved to be effective in inverting directions of the heart rate changes during BH. Hence, the model suggests that intra-subject differences in such sympatho-vagal balance may be one of the reasons for the contradicting experimental results.

Comparison of intraosseous and infiltration injections for venous lidocaine blood concentrations and heart rate changes after injection of 2% lidocaine with 1:100,000 epinephrine.

PubMed

Wood, Mark; Reader, Al; Nusstein, John; Beck, Mike; Padgett, David; Weaver, Joel

2005-06-01

The purpose of this prospective, randomized study was to compare the venous blood levels of lidocaine and heart rate changes after intraosseous and infiltration injections of 1.8 ml of 2% lidocaine with 1:100,000 epinephrine. Using a crossover design, 20 subjects randomly received an intraosseous and infiltration injection at two separate appointments. The heart rate was measured using a pulse oximeter. Venous blood samples were collected before the injections and at 2, 5, 10, 15, 20, 25, 30, 45, and 60 min after the injections. The blinded plasma samples were analyzed for lidocaine concentrations using high-performance liquid chromatography (HPLC). The intraosseous injection resulted in a statistically significant increase in heart rate, when compared to the infiltration injection, during solution deposition and for 2 min after the injection. The plasma levels of lidocaine were not statistically different for maxillary anterior intraosseous and infiltration injections when using 1.8 ml of 2% lidocaine with 1:100,000 epinephrine.

Understanding heart rate alarm adjustment in the intensive care units through an analytical approach.

PubMed

Fidler, Richard L; Pelter, Michele M; Drew, Barbara J; Palacios, Jorge Arroyo; Bai, Yong; Stannard, Daphne; Aldrich, J Matt; Hu, Xiao

2017-01-01

Heart rate (HR) alarms are prevalent in ICU, and these parameters are configurable. Not much is known about nursing behavior associated with tailoring HR alarm parameters to individual patients to reduce clinical alarm fatigue. To understand the relationship between heart rate (HR) alarms and adjustments to reduce unnecessary heart rate alarms. Retrospective, quantitative analysis of an adjudicated database using analytical approaches to understand behaviors surrounding parameter HR alarm adjustments. Patients were sampled from five adult ICUs (77 beds) over one month at a quaternary care university medical center. A total of 337 of 461 ICU patients had HR alarms with 53.7% male, mean age 60.3 years, and 39% non-Caucasian. Default HR alarm parameters were 50 and 130 beats per minute (bpm). The occurrence of each alarm, vital signs, and physiologic waveforms was stored in a relational database (SQL server). There were 23,624 HR alarms for analysis, with 65.4% exceeding the upper heart rate limit. Only 51% of patients with HR alarms had parameters adjusted, with a median upper limit change of +5 bpm and -1 bpm lower limit. The median time to first HR parameter adjustment was 17.9 hours, without reduction in alarms occurrence (p = 0.57). HR alarms are prevalent in ICU, and half of HR alarm settings remain at default. There is a long delay between HR alarms and parameters changes, with insufficient changes to decrease HR alarms. Increasing frequency of HR alarms shortens the time to first adjustment. Best practice guidelines for HR alarm limits are needed to reduce alarm fatigue and improve monitoring precision.

Manpower Staffing, Emergency Department Access and Consequences on Patient Outcomes

DTIC Science & Technology

2007-06-01

distance to the nearest hospital have higher death rates than those zip codes which experience a change. However, we hesitate to conclude that this may...1. Trend Analysis of Mortality Rates by Distance Categories: 1990-2004 Figure 6 presents heart-related death rates for the State of California from...1990- 2004. The graph shows a distinct layering of heart-related death rates across the three distance categories. The population which experiences

Biomarkers in Persistent AF and Heart Failure: Impact of Catheter Ablation Compared with Rate Control.

PubMed

Jones, David G; Haldar, Shouvik K; Donovan, Jacqueline; McDonagh, Theresa A; Sharma, Rakesh; Hussain, Wajid; Markides, Vias; Wong, Tom

2016-09-01

To investigate the effects of catheter ablation and rate control strategies on cardiac and inflammatory biomarkers in patients with heart failure and persistent atrial fibrillation (AF). Patients were recruited from the ARC-HF trial (catheter Ablation vs Rate Control for management of persistent AF in Heart Failure, NCT00878384), which compared ablation with rate control for persistent AF in heart failure. B-type natriuretic peptide (BNP), midregional proatrial natriuretic peptide (MR-proANP), apelin, and interleukin-6 (IL-6) were assayed at baseline, 3 months, 6 months, and 12 months. The primary end point, analyzed per-protocol, was changed from baseline at 12 months. Of 52 recruited patients, 24 ablation and 25 rate control subjects were followed to 12 months. After 1.2 ± 0.5 procedures, sinus rhythm was present in 22 (92%) ablation patients; under rate control, rate criteria were achieved in 23 (96%) of 24 patients remaining in AF. At 12 months, MR-proANP fell significantly in the ablation arm (-106.0 pmol/L, interquartile range [IQR] -228.2 to -60.6) compared with rate control (-28.7 pmol/L, IQR -69 to +9.5, P = 0.028). BNP showed a similar trend toward reduction (P = 0.051), with no significant difference in apelin (P = 0.13) or IL-6 (P = 0.68). Changes in MR-proANP and BNP correlated with peak VO2 and ejection fraction, and MR-proANP additionally with quality-of-life score. Catheter ablation, compared with rate control, in patients with heart failure and persistent AF was associated with significant reduction in MR-proANP, which correlated with physiological and symptomatic improvement. Ablation-based rhythm control may induce beneficial cardiac remodeling, unrelated to changes in inflammatory state. This may have prognostic implications, which require confirmation by event end point studies. © 2016 Wiley Periodicals, Inc.

Influence of transvaginal ultrasound-guided follicular punctures in the mare on heart rate, respiratory rate, facial expression changes, and salivary cortisol as pain scoring.

PubMed

Diego, Rodrigo; Douet, Cécile; Reigner, Fabrice; Blard, Thierry; Cognié, Juliette; Deleuze, Stefan; Goudet, Ghylène

2016-10-15

Transvaginal ultrasound-guided follicular punctures are widely used in the mare for diagnosis, research, and commercial applications. The objective of our study was to determine their influence on pain, stress, and well-being in the mare, by evaluating heart rate, breath rate, facial expression changes, and salivary cortisol before, during, and after puncture. For this experiment, 21 pony mares were used. Transvaginal ultrasound-guided aspirations were performed on 11 mares. After injections for sedation, analgesia, and antispasmodia, the follicles from both ovaries were aspirated with a needle introduced through the vagina wall into the ovary. In the control group, 10 mares underwent similar treatments and injections, but no follicular aspiration. Along the session, heart rate and breath rate were evaluated by a trained veterinarian, ears position, eyelid closure, and contraction of facial muscles were evaluated, and salivary samples were taken for evaluation of cortisol concentration. A significant relaxation was observed after sedative injection in the punctured and control mares, according to ear position, eyelid closure, and contraction of facial muscles, but no difference between punctured and control animals was recorded. No significant modification of salivary cortisol concentration during puncture and no difference between punctured and control mares at any time were observed. No significant modification of the breath rate was observed along the procedure for the punctured and the control mares. Heart rate increased significantly but transiently when the needle was introduced in the ovary and was significantly higher at that time for the punctured mares than that for control mares. None of the other investigated parameters were affected at that time, suggesting discomfort is minimal and transient. Improving analgesia, e.g., through a multimodal approach, during that possibly more sensitive step could be recommended. The evaluation of facial expression changes and heart rate is easy-to-use and accurate tools to evaluate pain and well-being of the mare. Copyright © 2016 Elsevier Inc. All rights reserved.

Sympathovagal imbalance in hyperthyroidism.

PubMed

Burggraaf, J; Tulen, J H; Lalezari, S; Schoemaker, R C; De Meyer, P H; Meinders, A E; Cohen, A F; Pijl, H

2001-07-01

We assessed sympathovagal balance in thyrotoxicosis. Fourteen patients with Graves' hyperthyroidism were studied before and after 7 days of treatment with propranolol (40 mg 3 times a day) and in the euthyroid state. Data were compared with those obtained in a group of age-, sex-, and weight-matched controls. Autonomic inputs to the heart were assessed by power spectral analysis of heart rate variability. Systemic exposure to sympathetic neurohormones was estimated on the basis of 24-h urinary catecholamine excretion. The spectral power in the high-frequency domain was considerably reduced in hyperthyroid patients, indicating diminished vagal inputs to the heart. Increased heart rate and mid-frequency/high-frequency power ratio in the presence of reduced total spectral power and increased urinary catecholamine excretion strongly suggest enhanced sympathetic inputs in thyrotoxicosis. All abnormal features of autonomic balance were completely restored to normal in the euthyroid state. beta-Adrenoceptor antagonism reduced heart rate in hyperthyroid patients but did not significantly affect heart rate variability or catecholamine excretion. This is in keeping with the concept of a joint disruption of sympathetic and vagal inputs to the heart underlying changes in heart rate variability. Thus thyrotoxicosis is characterized by profound sympathovagal imbalance, brought about by increased sympathetic activity in the presence of diminished vagal tone.

[Corrective effect of aromatherapy on indices of heart rate variability in students under exam stress conditions].

PubMed

Abrahamyan, H T; Minasyan, S M

2016-01-01

There were investigated changes in indices of the activity of regulatory mechanisms of heart rhythm in student under exam stress conditions and the possibility of their correction with aid of aromatherapy. The examination stress was established to be accompanied by pronounced shifts of integral and spectral indices of heart rhythm in students, indicating to the activation of the sympathetic circuit of Autonomic Nervous System in conditions of examination stress. A positive, relaxation impact of the essential oil of orange on the investigated indices was also recorded. The latter is expressed by weakly pronounced changes or lack of them in data of integral and spectral heart rate indices in students from the experimental group, that indicates to the stabilizing effect of used ethereal oil on the psycho-physiological state of students in conditions of exam stress

Effects of Breast Milk and Vanilla Odors on Premature Neonate's Heart Rate and Blood Oxygen Saturation During and After Venipuncture.

PubMed

Neshat, Hanieh; Jebreili, Mahnaz; Seyyedrasouli, Aleheh; Ghojazade, Morteza; Hosseini, Mohammad Bagher; Hamishehkar, Hamed

2016-06-01

Different studies have shown that the use of olfactory stimuli during painful medical procedures reduces infants' response to pain. The main purpose of the current study was to investigate the effect of breast milk odor and vanilla odor on premature infants' vital signs including heart rate and blood oxygen saturation during and after venipuncture. A total of 135 preterm infants were randomly selected and divided into three groups of control, vanilla odor, and breast milk odor. Infants in the breast milk group and the vanilla group were exposed to breast milk odor and vanilla odor from 5 minutes prior to sampling until 30 seconds after sampling. The results showed that breast milk odor has a significant effect on the changes of neonatal heart rate and blood oxygen saturation during and after venipuncture and decreased the variability of premature infants' heart rate and blood oxygen saturation. Vanilla odor has no significant effect on premature infants' heart rate and blood oxygen saturation. Breast milk odor can decrease the variability of premature infants' heart rate and blood oxygen saturation during and after venipuncture. Copyright © 2015. Published by Elsevier B.V.

A Bayesian approach to assess heart disease mortality among persons with diabetes in the presence of missing data.

PubMed

Cadwell, Betsy L; Boyle, James P; Tierney, Edward F; Thompson, Theodore J

2007-09-01

Some states' death certificate form includes a diabetes yes/no check box that enables policy makers to investigate the change in heart disease mortality rates by diabetes status. Because the check boxes are sometimes unmarked, a method accounting for missing data is needed when estimating heart disease mortality rates by diabetes status. Using North Dakota's data (1992-2003), we generate the posterior distribution of diabetes status to estimate diabetes status among those with heart disease and an unmarked check box using Monte Carlo methods. Combining this estimate with the number of death certificates with known diabetes status provides a numerator for heart disease mortality rates. Denominators for rates were estimated from the North Dakota Behavioral Risk Factor Surveillance System. Accounting for missing data, age-adjusted heart disease mortality rates (per 1,000) among women with diabetes were 8.6 during 1992-1998 and 6.7 during 1999-2003. Among men with diabetes, rates were 13.0 during 1992-1998 and 10.0 during 1999-2003. The Bayesian approach accounted for the uncertainty due to missing diabetes status as well as the uncertainty in estimating the populations with diabetes.

Case studies on the effect of exercise and hot water submersion on intracardiac temperature and the performance of a pacemaker which varies pacing rate based on temperature.

PubMed

Fearnot, N E; Kitoh, O; Fujita, T; Okamura, H; Smith, H J; Calderini, M

1989-05-01

The effectiveness of using blood temperature change as an indicator to automatically vary heart rate physiologically was evaluated in 3 patients implanted with Model Sensor Kelvin 500 (Cook Pacemaker Corporation, Leechburg, PA, USA) pacemakers. Each patient performed two block-randomized treadmill exercise tests: one while programmed for temperature-based, rate-modulated pacing and the other while programmed without rate modulation. In 1 pacemaker patient and 4 volunteers, heart rates were recorded during exposure to a hot water bath. Blood temperature measured at 10 sec intervals and pacing rate measured at 1 min intervals were telemetered to a diagnostic programmer and data collector for storage and transfer to a computer. Observation comments and ECG-derived heart rates were manually recorded. The temperature-based pacemaker was shown to respond promptly not only to physical exertion but also to emotionally caused stress and submersion in a hot bath. These events cause increased heart rate in the normal heart. Using a suitable algorithm to process the measurement of blood temperature, it was possible to produce appropriate pacing rates in paced patients.

Increase in serum noradrenaline concentration by short dives with bradycardia in Indo-Pacific bottlenose dolphin Tursiops aduncus.

PubMed

Suzuki, Miwa; Tomoshige, Mika; Ito, Miki; Koga, Sotaro; Yanagisawa, Makio; Bungo, Takashi; Makiguchi, Yuya

2017-07-01

In cetaceans, diving behavior immediately induces a change in blood circulation to favor flow to the brain and heart; this is achieved by intense vasoconstriction of the blood vessels that serve other organs. This blood circulation response is allied to a decrease in heart rate in order to optimize oxygen usage during diving. Vasoconstrictors are present in all mammals and stimulate the contraction of the smooth muscle in the walls of blood vessels. The most important of these vasoconstrictors are the hormones adrenaline (A), noradrenaline (NA), and angiotensin II (ANG II). At present, the contribution of these hormones to vasoconstriction during diving in cetaceans is unclear. To elucidate their possible roles, changes in serum levels of A, NA and ANG II were monitored together with heart rate in the Indo-Pacific bottlenose dolphin Tursiops aduncus during 90 and 180s dives. Both brief diving periods induced an increase in serum NA concentration and a decrease in heart rate; however, no changes were detected in serum levels of A or ANG II. These data indicate that NA may play a role in diving-induced vasoconstriction. Copyright © 2017 Elsevier Inc. All rights reserved.

'Athlete's heart' in prepubertal children.

PubMed

Rowland, T W; Delaney, B C; Siconolfi, S F

1987-05-01

Bradycardia, cardiomegaly, heart murmurs, and ECG changes are typically observed in adult endurance athletes, but frequency of such changes among children involved in sports training is unclear. Pediatricians need to be aware of whether these features of the "athlete's heart" occur in their patients, because such features may mimic those of cardiac disease. Fourteen prepubertal competitive male swimmers were evaluated by physical examination, ECG and echocardiogram, and findings were compared to those of a group of active but nontrained control boys. Lower resting heart rates and echocardiographic manifestations of chronic left ventricular volume overload were observed among the swimmers. These changes were not manifest on physical examination, however, and no significant ECG alterations were identified among the athletes. These findings indicate that, although features of the athlete's heart are present in children involved in endurance training, seldom will these findings simulate heart disease or be apparent on routine clinical examination.

Reduced left ventricular filling following blood volume extraction does not result in compensatory augmentation of cardiac mechanics.

PubMed

Lord, Rachel; MacLeod, David; George, Keith; Oxborough, David; Shave, Rob; Stembridge, Mike

2018-04-01

What is the central question of this study? A reduction in left ventricular (LV) filling, and concomitant increase in heart rate, augments LV mechanics to maintain stroke volume (SV); however, the impact of reduced LV filling in isolation on SV and LV mechanics is currently unknown. What is the main finding and its importance? An isolated decrease in LV filling did not provoke a compensatory increase in mechanics to maintain SV; in contrast, LV mechanics and SV were reduced. These data indicate that when LV filling is reduced without changes in heart rate, LV mechanics do not compensate to maintain SV. An acute non-invasive reduction in preload has been shown to augment cardiac mechanics to maintain stroke volume and cardiac output. Such interventions induce concomitant changes in heart rate, whereas blood volume extraction reduces preload without changes in heart rate. Therefore, the purpose of this study was to determine whether a preload reduction in isolation resulted in augmented stroke volume achieved via enhanced cardiac mechanics. Nine healthy volunteers (four female, age 29 ± 11 years) underwent echocardiography for the assessment of left ventricular (LV) volumes and mechanics in a supine position at baseline and end extraction after the controlled removal of 25% of total blood volume (1062 ± 342 ml). Arterial blood pressure was monitored continuously by a pressure transducer attached to an indwelling radial artery catheter. Heart rate and total peripheral resistance were unchanged from baseline to end extraction, but systolic blood pressure was reduced (from 148 to 127 mmHg). From baseline to end extraction there were significant reductions in left ventricular end-diastolic volume (from 89 to 71 ml) and stroke volume (from 56 to 37 ml); however, there was no change in LV twist, basal or apical rotation. In contrast, LV longitudinal strain (from -20 to -17%) and basal circumferential strain (from -22 to -19%) were significantly reduced from baseline to end extraction. In conclusion, a reduction in preload during blood volume extraction does not result in compensatory changes in stroke volume or cardiac mechanics. Our data suggest that LV strain is dependent on LV filling and consequent geometry, whereas LV twist could be mediated by heart rate. © 2018 The Authors. Experimental Physiology © 2018 The Physiological Society.

Effects of milk flow on the physiological and behavioural responses to feeding in an infant with hypoplastic left heart syndrome.

PubMed

Pados, Britt F; Thoyre, Suzanne M; Estrem, Hayley H; Park, Jinhee; Knafl, George J; Nix, Brant

2017-01-01

Infants with hypoplastic left heart syndrome often experience difficulty with oral feeding, which contributes to growth failure, morbidity, and mortality. In response to feeding difficulty, clinicians often change the bottle nipple, and thus milk flow rate. Slow-flow nipples have been found to reduce the stress of feeding in other fragile infants, but no research has evaluated the responses of infants with hypoplastic left heart syndrome to alterations in milk flow. The purpose of this study was to evaluate the physiological and behavioural responses of an infant with hypoplastic left heart syndrome to bottle feeding with either a slow-flow (Dr. Brown's Preemie) or a standard-flow (Dr. Brown's Level 2) nipple. A single infant was studied for three feedings: two slow-flow and one standard-flow. Oral feeding, whether with a slow-flow or a standard-flow nipple, was distressing for this infant. During slow-flow feeding, she experienced more coughing events, whereas during standard-flow she experienced more gagging. Disengagement and compelling disorganisation were most common during feeding 3, that is slow-flow, which occurred 2 days after surgical placement of a gastrostomy tube. Clinically significant changes in heart rate, oxygen saturation, and respiratory rate were seen during all feedings. Heart rate was higher during standard-flow and respiratory rate was higher during slow-flow. Further research is needed to examine the responses of infants with hypoplastic left heart syndrome to oral feeding and to identify strategies that will support these fragile infants as they learn to feed. Future research should evaluate an even slower-flow nipple along with additional supportive feeding strategies.

Endothelial function is unaffected by changing between carvedilol and metoprolol in patients with heart failure-a randomized study

PubMed Central

2011-01-01

Background Carvedilol has been shown to be superior to metoprolol tartrate to improve clinical outcomes in patients with heart failure (HF), yet the mechanisms responsible for these differences remain unclear. We examined if there were differences in endothelial function, insulin stimulated endothelial function, 24 hour ambulatory blood pressure and heart rate during treatment with carvedilol, metoprolol tartrate and metoprolol succinate in patients with HF. Methods Twenty-seven patients with mild HF, all initially treated with carvedilol, were randomized to a two-month treatment with carvedilol, metoprolol tartrate or metoprolol succinate. Venous occlusion plethysmography, 24-hour blood pressure and heart rate measurements were done before and after a two-month treatment period. Results Endothelium-dependent vasodilatation was not affected by changing from carvedilol to either metoprolol tartrate or metoprolol succinate. The relative forearm blood flow at the highest dose of serotonin was 2.42 ± 0.33 in the carvedilol group at baseline and 2.14 ± 0.24 after two months continuation of carvedilol (P = 0.34); 2.57 ± 0.33 before metoprolol tartrate treatment and 2.42 ± 0.55 after treatment (p = 0.74) and in the metoprolol succinate group 1.82 ± 0.29 and 2.10 ± 0.37 before and after treatment, respectively (p = 0.27). Diurnal blood pressures as well as heart rate were also unchanged by changing from carvedilol to metoprolol tartrate or metoprolol succinate. Conclusion Endothelial function remained unchanged when switching the beta blocker treatment from carvedilol to either metoprolol tartrate or metoprolol succinate in this study, where blood pressure and heart rate also remained unchanged in patients with mild HF. Trial registration Current Controlled Trials NCT00497003 PMID:21999413

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

PubMed

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

2007-10-01

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

β1 -Adrenoceptor, but not β2 -adrenoceptor, subtype regulates heart rate in type 2 diabetic rats in vivo.

PubMed

Cook, Rosalind F; Bussey, Carol T; Mellor, Kimberley M; Cragg, Patricia A; Lamberts, Regis R

2017-08-01

What is the central question of the study? The sympathetic system regulates heart rate via β-adrenoceptors; this is impaired during diabetes. However, the specific β-adrenoceptor subtype contributions in heart rate regulation in diabetes in vivo are unknown. What is the main finding and its importance? Telemetric recordings in conscious non-diabetic and type 2 diabetic rats demonstrated that the β 1 -adrenoceptor subtype, and not the β 2 -adrenoceptor, regulated the lower resting heart rate and increased β-adrenoceptor responsiveness in diabetes in vivo. This provides new physiological insight into the dysregulation of heart rate in type 2 diabetes, which is important for improving therapeutic strategies targeting the diabetic chronotropic incompetence. β-Adrenoceptor blockers are widely used to reduce heart rate, the strongest predictor of mortality in cardiac patients, but are less effective in diabetic patients. This study aimed to determine the specific contributions of β 1 - and β 2 -adrenoceptor subtypes to chronotropic responses in type 2 diabetes in vivo, which are currently unknown. Type 2 diabetic and non-diabetic rats were implanted with radiotelemeters to measure arterial blood pressure and derive heart rate in conscious conditions. Vascular access ports were implanted to inject isoprenaline (β 1 - and β 2 -adrenoceptor agonist, 0.1-300 μg kg -1 ) in the presence of atenolol (β 1 -adrenoceptor antagonist, 2000 μg kg -1 ) or nadolol (β 1 - and β 2 -adrenoceptor agonist, 4000 μg kg -1 ) to determine the chronotropic contributions of the β-adrenoceptor subtypes. Resting heart rate was reduced in diabetic rats (388 ± 62 versus 290 ± 37 beats min -1 non-diabetic versus diabetic, P < 0.05, mean ± SD), which remained after atenolol or nadolol administration. Overall β-adrenoceptor chronotropic responsiveness was increased in diabetic rats (change in heart rate at highest dose of isoprenaline: 135 ± 66 versus 205 ± 28 beats min -1 , non-diabetic versus diabetic, P < 0.05), a difference that diminished after β 1 -adrenoceptor blockade with atenolol (change in heart rate at highest dose of isoprenaline: 205 ± 37 versus 195 ± 22 beats min -1 , non-diabetic versus diabetic, P < 0.05). In conclusion, the β 1 -adrenoceptor is the main subtype to modulate chronotropic β-adrenoceptor responses in healthy and diabetic rats. This study provides new insights into the pathological basis of dysregulation of heart rate in type 2 diabetes, which could be important for improving the current therapeutic strategies targeting diabetic chronotropic incompetence. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Control of skin blood flow, sweating, and heart rate - Role of skin vs. core temperature

NASA Technical Reports Server (NTRS)

Wyss, C. R.; Brengelmann, G. L.; Johnson, J. M.; Rowell, L. B.; Niederberger, M.

1974-01-01

A study was conducted to generate quantitative expressions for the influence of core temperature, skin temperature, and the rate of change of skin temperature on sweat rate, skin blood flow, and heart rate. A second goal of the study was to determine whether the use of esophageal temperature rather than the right atrial temperature as a measure of core temperature would lead to different conclusions about the control of measured effector variables.

Using time-series intervention analysis to model cow heart rate affected by programmed audio and environmental/physiological cues

USDA-ARS?s Scientific Manuscript database

This research is the first use of the Box-Jenkins time-series models to describe changes in heart rate (HR) of free-ranging crossbred cows (Bos taurus) receiving both programmed audio cues from directional virtual fencing (DVFTM) devices and non-programmed environmental/physiological cues. The DVFT...

Systemic Effects of Intracoronary Nitroglycerin during Coronary Angiography in Children after Heart Transplantation

PubMed Central

Lara, Diego A.; Olive, Mary K.; George, James F.; Brown, Robert N.; Carlo, Waldemar F.; Colvin, Edward V.; Steenwyck, Brad L.

2014-01-01

Coronary spasm during coronary angiography for vasculopathy in children can be prevented by the intracoronary administration of nitroglycerin. We reviewed the anesthesia and catheterization reports and charts for pediatric transplant recipients who underwent angiography from 2005 through 2010. Correlation analysis was used to study the relation of post-injection systolic blood pressure (SBP) to nitroglycerin dose. Forty-one angiographic evaluations were performed on 25 patients (13 male and 12 female). Mean age was 9.9 ± 3.2 years (range, 3.3–16.1 yr). The mean total dose of nitroglycerin was 2.93 ± 1.60 µg/kg (range, 1–8 µg/kg). There was a significant drop between the baseline SBP (mean, 106 ± 21.6 mmHg) and the lowest mean SBP before nitroglycerin administration (78 ± 13.2, P <0.0001, paired t test). There was no significant additional change in SBP (mean after nitroglycerin administration, 80.7 ± 13.1 mmHg; P = 0.2). There was a significant drop in lowest heart rate between baseline (109 ± 16.5 beats/min) and before nitroglycerin administration (89 ± 14.3 beats/min; P <0.0001, paired t test). There was no significant additional change in heart rate (mean heart rate after nitroglycerin, 84 ± 17.7 beats/min; P = 0.09). There were 2 interventions for SBP before nitroglycerin and 2 after nitroglycerin. One child experienced a transient ST-T–segment change during angiography after nitroglycerin. In the highest dose range, the additional decrease in SBP was 7.2 mmHg (P=0.03). Routine intracoronary nitroglycerin administration in this dose range produced no significant changes in SBP or heart rate in children. PMID:24512395

Systemic effects of intracoronary nitroglycerin during coronary angiography in children after heart transplantation.

PubMed

Lara, Diego A; Olive, Mary K; George, James F; Brown, Robert N; Carlo, Waldemar F; Colvin, Edward V; Steenwyck, Brad L; Pearce, F Bennett

2014-02-01

Coronary spasm during coronary angiography for vasculopathy in children can be prevented by the intracoronary administration of nitroglycerin. We reviewed the anesthesia and catheterization reports and charts for pediatric transplant recipients who underwent angiography from 2005 through 2010. Correlation analysis was used to study the relation of post-injection systolic blood pressure (SBP) to nitroglycerin dose. Forty-one angiographic evaluations were performed on 25 patients (13 male and 12 female). Mean age was 9.9 ± 3.2 years (range, 3.3-16.1 yr). The mean total dose of nitroglycerin was 2.93 ± 1.60 µg/kg (range, 1-8 µg/kg). There was a significant drop between the baseline SBP (mean, 106 ± 21.6 mmHg) and the lowest mean SBP before nitroglycerin administration (78 ± 13.2, P <0.0001, paired t test). There was no significant additional change in SBP (mean after nitroglycerin administration, 80.7 ± 13.1 mmHg; P = 0.2). There was a significant drop in lowest heart rate between baseline (109 ± 16.5 beats/min) and before nitroglycerin administration (89 ± 14.3 beats/min; P <0.0001, paired t test). There was no significant additional change in heart rate (mean heart rate after nitroglycerin, 84 ± 17.7 beats/min; P = 0.09). There were 2 interventions for SBP before nitroglycerin and 2 after nitroglycerin. One child experienced a transient ST-T-segment change during angiography after nitroglycerin. In the highest dose range, the additional decrease in SBP was 7.2 mmHg (P=0.03). Routine intracoronary nitroglycerin administration in this dose range produced no significant changes in SBP or heart rate in children.

Real-world cardiovascular assessment of mirabegron treatment in patients with overactive bladder and concomitant cardiovascular disease: Results of a Japanese post-marketing study.

PubMed

Katoh, Takao; Kuwamoto, Kana; Kato, Daisuke; Kuroishi, Kentarou

2016-12-01

To assess the effect of 25 or 50 mg mirabegron on cardiovascular end-points and adverse drug reactions in real-world Japanese patients with overactive bladder and cardiovascular disease. Participants had overactive bladder, a history of/coexisting cardiovascular disease and a 12-lead electrocardiogram carried out ≤7 days before initiating 4 weeks of mirabegron treatment. Patients with "serious cardiovascular disease" (class III or IV on the New York Heart Association functional classification and further confirmed by expert analysis) were excluded. Patient demographics, physical characteristics and cardiovascular history were recorded. After 4 weeks, patients underwent another electrocardiogram. Incidence of cardiovascular adverse drug reactions and change from baseline in electrocardiogram parameters (RR, PR, QRS intervals, Fridericia's corrected QT and heart rate) were assessed. Of 316 patients registered, 236 met criteria and had baseline/post-dose electrocardiograms: 61.9% male; 60.2% aged ≥75 years; 93.6% with coexisting cardiovascular disease, notably, arrhythmia (67.8%) and angina pectoris (19.1%). Starting mirabegron daily doses were 25 mg (19.9%) or 50 mg (80.1%). The incidence of cardiovascular adverse drug reactions was 5.51%. After 4 weeks, the mean heart rate increased by 1.24 b.p.m. (statistically significant, but clinically acceptable as per previous trials). No significant changes were observed in PR, QRS or Fridericia's corrected QT. No significant correlations in the total population or age-/sex-segregated subgroups were observed between baseline Fridericia's corrected QT and change at 4 weeks. No correlation for heart rate versus change from baseline heart rate with treatment was observed. Mirabegron was well tolerated in real-world Japanese patients with overactive bladder and coexisting cardiovascular disease. No unexpected cardiovascular safety concerns were observed. © 2016 The Japanese Urological Association.

Autonomic components of Complex Regional Pain Syndrome (CRPS) are favourably affected by Electrical Twitch-Obtaining Intramuscular Stimulation (ETOIMS): effects on blood pressure and heart rate.

PubMed

Chu, Jennifer; Bruyninckx, Frans; Neuhauser, Duncan V

2017-07-01

Favourable pain relief results on evoking autonomous twitches at myofascial trigger points with Electrical Twitch Obtaining Intramuscular Stimulation (ETOIMS). To document autonomic nervous system (ANS) dysfunction in Complex Regional Pain Syndrome (CRPS) from blood pressure (BP) and pulse/heart rate changes with ETOIMS. A patient with persistent pain regularly received serial ETOIMS sessions of 60, 90, 120 or ≥150 min over 24 months. Outcome measures include BP: systolic, diastolic, pulse pressure and pulse/heart rate, pre-session/immediate-post-session summed differences (SDPPP index), and pain reduction. His results were compared with that of two other patients and one normal control. Each individual represented the following maximal elicitable twitch forces (TWF) graded 1-5: maximum TWF2: control subject; maximum TWF3: CRPS patient with suspected ANS dysfunction; and maximum TWF4 and TWF5: two patients with respective slow-fatigue and fast-fatigue twitches who during ETOIMS had autonomous twitching at local and remote myotomes simultaneously from denervation supersensitivity. ETOIMS results between TWFs were compared using one-way analysis of variance test. The patients showed immediate significant pain reduction, BP and pulse/heart rate changes/reduction(s) except for diastolic BP in the TWF5 patient. TWF2 control subject had diastolic BP reduction with ETOIMS but not with rest. Linear regression showed TWF grade to be the most significant variable in pain reduction, more so than the number of treatments, session duration and treatment interval. TWF grade was the most important variable in significantly reducing outcome measures, especially pulse/heart rate. Unlike others, the TWF3 patient had distinctive reductions in SDPPP index. Measuring BP and pulse/heart rate is clinically practical for alerting ANS dysfunction maintained CRPS. SDPPP index (≥26) and pulse/heart rate (≥8) reductions with almost every ETOIMS treatment, plus inability to evoke autonomous twitches due to pain-induced muscle hypertonicity, are pathognomonic of this problem.

Whole-Body Vibration Training Improves Heart Rate Variability and Body Fat Percentage in Obese Hispanic Postmenopausal Women.

PubMed

Severino, Gregory; Sanchez-Gonzalez, Marcos; Walters-Edwards, Michelle; Nordvall, Michael; Chernykh, Oksana; Adames, Jason; Wong, Alexei

2017-07-01

The present study examined the effects of a 6-week whole-body vibration training (WBVT) regimen on heart rate variability (HRV) and body composition in obese Hispanic postmenopausal women. Participants were randomly assigned to either WBVT (n = 13) or a nonexercising control group (n = 14). HRV and body composition were measured before and after 6 weeks. There was a significant group by time interaction (P < .05) for heart rate, sympathovagal balance, and body fat percentage (BF%) such that all significantly decreased (P < .05); and R-R intervals significantly increased (P < .05) following WBVT compared to no changes after control. The changes in sympathovagal balance were correlated with changes in BF% (r = .63, P < .05). Our findings indicate that WBVT improves HRV and BF% in obese Hispanic postmenopausal women. The improvement in BF% partially explained the decrease in sympathovagal balance. Since obese and older individuals are at increased risk of developing cardiovascular diseases, they could potentially benefit from WBVT.

Effect of mobile phone radiation on heart rate variability.

PubMed

Ahamed, V I Thajudin; Karthick, N G; Joseph, Paul K

2008-06-01

The rapid increase in the use of mobile phones (MPs) in recent years has raised the problem of health risk connected with high-frequency electromagnetic fields. There are reports of headache, dizziness, numbness in the thigh, and heaviness in the chest among MP users. This paper deals with the neurological effect of electromagnetic fields radiated from MPs, by studies on heart rate variability (HRV) of 14 male volunteers. As heart rate is modulated by the autonomic nervous system, study of HRV can be used for assessing the neurological effect. The parameters used in this study for quantifying the effect on HRV are scaling exponent and sample entropy. The result indicates an increase in both the parameters when MP is kept close to the chest and a decrease when kept close to the head. MP has caused changes in HRV indices and the change varied with its position, but the changes cannot be considered significant as the p values are high.

The effects of incubation temperature and experimental design on heart rates of lizard embryos.

PubMed

Hulbert, Austin C; Mitchell, Timothy S; Hall, Joshua M; Guiffre, Cassia M; Douglas, Danielle C; Warner, Daniel A

2017-08-01

Many studies of phenotypic plasticity alter environmental conditions during embryonic development, yet only measure phenotypes at the neonatal stage (after embryonic development). However, measuring aspects of embryo physiology enhances our understanding of how environmental factors immediately affect embryos, which aids our understanding of developmental plasticity. While current research on reptile developmental plasticity has demonstrated that fluctuating incubation temperatures affect development differently than constant temperatures, most research on embryo physiology is still performed with constant temperature experiments. In this study, we noninvasively measured embryonic heart rates of the brown anole (Anolis sagrei), across ecologically relevant fluctuating temperatures. We incubated eggs under temperatures measured from potential nests in the field and examined how heart rates change through a diel cycle and throughout embryonic development. We also evaluated how experimental design (e.g., repeated vs. single measures designs, constant vs. fluctuating temperatures) and different protocols (e.g., removing eggs from incubators) might influence heart rate. We found that heart rates were correlated with daily temperature and increased through development. Our findings suggest that experimenters have reasonable flexibility in choosing an experimental design to address their questions; however, some aspects of design and protocol can potentially influence estimations of heart rates. Overall, we present the first ecologically relevant measures of anole embryonic heart rates and provide recommendations for experimental designs for future experiments. © 2017 Wiley Periodicals, Inc.

Resting heart rate and the development of antisocial behavior from age 9 to 14: genetic and environmental influences.

PubMed

Baker, Laura A; Tuvblad, Catherine; Reynolds, Chandra; Zheng, Mo; Lozano, Dora Isabel; Raine, Adrian

2009-01-01

The genetic and environmental basis of a well-replicated association between antisocial behavior (ASB) and resting heart rate was investigated in a longitudinal twin study, based on two measurements between the ages of 9 and 14 years. ASB was defined as a broad continuum of externalizing behavior problems, assessed at each occasion through a composite measure based on parent ratings of trait aggression, delinquent behaviors, and psychopathic traits in their children. Parent ratings of ASB significantly decreased across age from childhood to early adolescence, although latent growth models indicated significant variation and twin similarity in the growth patterns, which were explained almost entirely by genetic influences. Resting heart rate at age 9-10 years old was inversely related to levels of ASB but not change patterns of ASB across age or occasions. Biometrical analyses indicated significant genetic influences on heart rate during childhood, as well as ASB throughout development from age 9 to 14. Both level and slope variation were significantly influenced by genetic factors. Of importance, the low resting heart rate and ASB association was significantly and entirely explained by their genetic covariation, although the heritable component of heart rate explained only a small portion (1-4%) of the substantial genetic variance in ASB. Although the effect size is small, children with low resting heart rate appear to be genetically predisposed toward externalizing behavior problems as early as age 9 years old.

Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

NASA Astrophysics Data System (ADS)

Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

2015-08-01

The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress.

Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

PubMed Central

Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

2015-01-01

The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress. PMID:26286628

The effects of N-acetylcysteine on cisplatin-induced changes of cardiodynamic parameters within coronary autoregulation range in isolated rat hearts.

PubMed

Rosic, Gvozden; Selakovic, Dragica; Joksimovic, Jovana; Srejovic, Ivan; Zivkovic, Vladimir; Tatalović, Nikola; Orescanin-Dusic, Zorana; Mitrovic, Slobodanka; Ilic, Milena; Jakovljevic, Vladimir

2016-02-03

The aim of this study was to evaluate the effects of chronic NAC administration along with cisplatin on cisplatin-induced cardiotoxicity by means of coronary flow (CF), cardiodynamic parameters, oxidative stress markers and morphological changes in isolated rat heart. Isolated hearts of Wistar albino rats (divided into four groups: control, cisplatin, NAC and cisplatin+NAC group) were perfused according to Langendorff technique at constant coronary perfusion pressure starting at 50 and gradually increased to 65, 80, 95 and 110 cm H2O to evaluate cardiodynamic parameters within autoregulation range. Samples of coronary venous effluent (CVE) were collected for determination of CF and biochemical assays, and heart tissue samples for biochemical assays and histopathological examination. Cisplatin treatment decreased CF and heart rate, and increased left ventricular systolic pressure and maximum left ventricular pressure development rate. Cisplatin increased H2O2 and TBARS, but decreased NO2(-) levels in CVE. In tissue samples, cisplatin reduced pathological alterations in myocardium and coronary vessels, with no changes in the amount of total glutathione, as well as in activity of glutathione peroxidase and glutathione reductase. NAC coadministration, by reducing oxidative damage, attenuated cisplatin-induced changes of cardiodynamic and oxidative stress parameters, as well as morphological changes in myocardium and coronary vasculature. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effect of screen-based media on energy expenditure and heart rate in 9- to 12-year-old children.

PubMed

Straker, Leon; Abbott, Rebecca

2007-11-01

This study compared the cardiovascular responses and energy costs of new and traditional screen based entertainments, as played by twenty 9- to 12-year-old children. Playing traditional electronic games resulted in little change to heart rate or energy expenditure compared with watching a DVD. In contrast, playing an active-input game resulted in a 59% increase in heart rate (p < .001) and a 224% increase in energy expenditure (p < .001) for boys and girls. The average heart rate of 130 bpm and energy expenditure of 0.13 kcal . min-1 . kg-1 achieved during active-input game use equates with moderate intensity activities such as basketball and jogging. Active-input electronic games might provide children with opportunities to engage with technology and be physically active at the same time.

Heart rate recovery and heart rate variability are unchanged in patients with coronary artery disease following 12 weeks of high-intensity interval and moderate-intensity endurance exercise training.

PubMed

Currie, Katharine D; Rosen, Lee M; Millar, Philip J; McKelvie, Robert S; MacDonald, Maureen J

2013-06-01

Decreased heart rate variability and attenuated heart rate recovery following exercise are associated with an increased risk of mortality in cardiac patients. This study investigated the effects of 12 weeks of moderate-intensity endurance exercise (END) and a novel low-volume high-intensity interval exercise protocol (HIT) on measures of heart rate recovery and heart rate variability in patients with coronary artery disease (CAD). Fourteen males with CAD participated in 12 weeks of END or HIT training, each consisting of 2 supervised exercise sessions per week. END consisted of 30-50 min of continuous cycling at 60% peak power output (PPO). HIT involved ten 1-min intervals at 88% PPO separated by 1-min intervals at 10% PPO. Heart rate recovery at 1 min and 2 min was measured before and after training (pre- and post-training, respectively) using a submaximal exercise bout. Resting time and spectral and nonlinear domain measures of heart rate variability were calculated. Following 12 weeks of END and HIT, there was no change in heart rate recovery at 1 min (END, 40 ± 12 beats·min(-1) vs. 37 ± 19 beats·min(-1); HIT, 31 ± 8 beats·min(-1) vs. 35 ± 8 beats·min(-1); p ≥ 0.05 for pre- vs. post-training) or 2 min (END, 44 ± 18 beats·min(-1) vs. 43 ± 19 beats·min(-1); HIT, 42 ± 10 beats·min(-1) vs. 50 ± 6 beats·min(-1); p ≥ 0.05 for pre- vs. post-training). All heart rate variability indices were unchanged following END and HIT training. In conclusion, neither END nor HIT exercise programs elicited training-induced improvements in cardiac autonomic function in patients with CAD. The absence of improvements with training may be attributed to the optimal medical management and normative pretraining state of our sample.

Understanding heart rate alarm adjustment in the intensive care units through an analytical approach

PubMed Central

Pelter, Michele M.; Drew, Barbara J.; Palacios, Jorge Arroyo; Bai, Yong; Stannard, Daphne; Aldrich, J. Matt; Hu, Xiao

2017-01-01

Background Heart rate (HR) alarms are prevalent in ICU, and these parameters are configurable. Not much is known about nursing behavior associated with tailoring HR alarm parameters to individual patients to reduce clinical alarm fatigue. Objectives To understand the relationship between heart rate (HR) alarms and adjustments to reduce unnecessary heart rate alarms. Methods Retrospective, quantitative analysis of an adjudicated database using analytical approaches to understand behaviors surrounding parameter HR alarm adjustments. Patients were sampled from five adult ICUs (77 beds) over one month at a quaternary care university medical center. A total of 337 of 461 ICU patients had HR alarms with 53.7% male, mean age 60.3 years, and 39% non-Caucasian. Default HR alarm parameters were 50 and 130 beats per minute (bpm). The occurrence of each alarm, vital signs, and physiologic waveforms was stored in a relational database (SQL server). Results There were 23,624 HR alarms for analysis, with 65.4% exceeding the upper heart rate limit. Only 51% of patients with HR alarms had parameters adjusted, with a median upper limit change of +5 bpm and -1 bpm lower limit. The median time to first HR parameter adjustment was 17.9 hours, without reduction in alarms occurrence (p = 0.57). Conclusions HR alarms are prevalent in ICU, and half of HR alarm settings remain at default. There is a long delay between HR alarms and parameters changes, with insufficient changes to decrease HR alarms. Increasing frequency of HR alarms shortens the time to first adjustment. Best practice guidelines for HR alarm limits are needed to reduce alarm fatigue and improve monitoring precision. PMID:29176776

State Anxiety and Nonlinear Dynamics of Heart Rate Variability in Students.

PubMed

Dimitriev, Dimitriy A; Saperova, Elena V; Dimitriev, Aleksey D

2016-01-01

Clinical and experimental research studies have demonstrated that the emotional experience of anxiety impairs heart rate variability (HRV) in humans. The present study investigated whether changes in state anxiety (SA) can also modulate nonlinear dynamics of heart rate. A group of 96 students volunteered to participate in the study. For each student, two 5-minute recordings of beat intervals (RR) were performed: one during a rest period and one just before a university examination, which was assumed to be a real-life stressor. Nonlinear analysis of HRV was performed. The Spielberger's State-Trait Anxiety Inventory was used to assess the level of SA. Before adjusting for heart rate, a Wilcoxon matched pairs test showed significant decreases in Poincaré plot measures, entropy, largest Lyapunov exponent (LLE), and pointwise correlation dimension (PD2), and an increase in the short-term fractal-like scaling exponent of detrended fluctuation analysis (α1) during the exam session, compared with the rest period. A Pearson analysis indicated significant negative correlations between the dynamics of SA and Poincaré plot axes ratio (SD1/SD2), and between changes in SA and changes in entropy measures. A strong negative correlation was found between the dynamics of SA and LLE. A significant positive correlation was found between the dynamics of SA and α1. The decreases in Poincaré plot measures (SD1, complex correlation measure), entropy measures, and LLE were still significant after adjusting for heart rate. Corrected α1 was increased during the exam session. As before, the dynamics of adjusted LLE was significantly correlated with the dynamics of SA. The qualitative increase in SA during academic examination was related to the decrease in the complexity and size of the Poincaré plot through a reduction of both the interbeat interval and its variation.

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

NASA Technical Reports Server (NTRS)

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

1996-01-01

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

Electrical stimulation of acupuncture points and blood pressure responses to postural changes: a pilot study.

PubMed

Jones, Alice Y M; Kwan, Y L; Leung, Nathan T F; Yu, Rachel P W; Wu, Cindy M Y; Warburton, Darren E R

2011-05-01

Application of transcutaneous electrical stimulation over acupuncture points (Acu-TENS) facilitates heart rate recovery after exercise and restores hemodynamic stability after open heart surgery. The role of Acu-TENS on cardiovascular parameters in response to postural changes has not been reported. To investigate (1) the effect of Acu-TENS on blood pressure responses to -10º head-down postural change and (2) whether such effects were associated with modulation by the autonomic nervous system. Sixteen healthy volunteers, mean age 22.8 (SD, 3.1) years, were subjected to a -10º head-down tilt from the supine position on 3 separate occasions and received in random order the following 3 intervention protocols for 40 minutes before the postural change: Acu-TENS (over bilateral acupuncture points, PC6), sham-TENS (TENS applied to the skin over the patellae), and control (no electrical output from the TENS device applied at PC6). Mean arterial pressure, large artery elasticity index, cardiac output, and heart rate were recorded and compared at different stimulation protocols in the supine and -10º head-down tilt positions. Spectral analysis of heart rate variability was used to determine any modulation by the autonomic nervous system. Change in large artery elasticity index was observed only in the Acu-TENS group (P < .05) and mean arterial pressure appeared most stable during Acu-TENS. Autonomic nervous system modulation was not apparent with spectral analysis, irrespective of intervention. Sympathetic activity predominated in all positions. Acu-TENS seems to reduce blood pressure changes with -10º head-down tilt with concomitant changes in arterial vessel tone.

Exposure to low mercury concentration in vivo impairs myocardial contractile function

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

Furieri, Lorena Barros; Fioresi, Mirian; Junior, Rogerio Faustino Ribeiro

2011-09-01

Increased cardiovascular risk after mercury exposure has been described but cardiac effects resulting from controlled chronic treatment are not yet well explored. We analyzed the effects of chronic exposure to low mercury concentrations on hemodynamic and ventricular function of isolated hearts. Wistar rats were treated with HgCl{sub 2} (1st dose 4.6 {mu}g/kg, subsequent dose 0.07 {mu}g/kg/day, im, 30 days) or vehicle. Mercury treatment did not affect blood pressure (BP) nor produced cardiac hypertrophy or changes of myocyte morphometry and collagen content. This treatment: 1) in vivo increased left ventricle end diastolic pressure (LVEDP) without changing left ventricular systolic pressure (LVSP)more » and heart rate; 2) in isolated hearts reduced LV isovolumic systolic pressure and time derivatives, and {beta}-adrenergic response; 3) increased myosin ATPase activity; 4) reduced Na{sup +}-K{sup +} ATPase (NKA) activity; 5) reduced protein expression of SERCA and phosphorylated phospholamban on serine 16 while phospholamban expression increased; as a consequence SERCA/phospholamban ratio reduced; 6) reduced sodium/calcium exchanger (NCX) protein expression and {alpha}-1 isoform of NKA, whereas {alpha}-2 isoform of NKA did not change. Chronic exposure for 30 days to low concentrations of mercury does not change BP, heart rate or LVSP but produces small but significant increase of LVEDP. However, in isolated hearts mercury treatment promoted contractility dysfunction as a result of the decreased NKA activity, reduction of NCX and SERCA and increased PLB protein expression. These findings offer further evidence that mercury chronic exposure, even at small concentrations, is an environmental risk factor affecting heart function. - Highlights: > Unchanges blood pressure, heart rate, systolic pressure. > Increases end diastolic pressure. > Promotes cardiac contractility dysfunction. > Decreases NKA activity, NCX and SERCA, increases PLB protein expression. > Small concentrations constitutes environmental cardiovascular risk factor.« less

Changes in extracellular muscle volume affect heart rate and blood pressure responses to static exercise

NASA Astrophysics Data System (ADS)

Baum, K.; Essfeld, D.; Stegemann, J.

To investigate the effect of μg-induced peripheral extracellular fluid reductions on heart rate and blood pressure during isometric exercise, six healthy male subjects performed three calf ergometer test with different extracellular volumes of working muscles. In all tests, body positions during exercise were identical (supine with the knee joint flexed to 900). After a pre-exercise period of 25 min, during which calf volumes were manipulated, subjects had to counteract an external force of 180 N for 5 min. During the pre-exercise period three different protocols were applied. Test A: Subjects rested in the exercise position; test B: Body position was the same as in A but calf volume was increased by venous congestion (cuffs inflated to 80 mm Hg); test C: Calf volumes were decreased by a negative hydrostatic pressure (calves about 40 cm above heart level with the subjects supine). To clamp the changed calf volumes in tests B and C, cuffs were inflated to 300 mm Hg 5 min before the onset of exercise. This occlusion was maintained until termination of exercise. Compared to tests A and B, the reduced volume of test C led to significant increases in heart rate and blood pressure during exercise. Oxygen uptake did not exceed resting levels in B and C until cuffs were deflated, indicating that exclusively calf muscles contributed to the neurogenic peripheral drive. It is concluded that changes in extracellular muscle volume have to be taken into account when comparing heart rate and blood pressure during lg- and μg- exercise.

A Randomized Prospective Study Of The Use Of Ipads In Reducing Anxiety During Cast Room Procedures

PubMed Central

Ko, Justine S.; Whiting, Zachariah; Nguyen, Cynthia; Liu, Raymond W; Gilmore, Allison

2016-01-01

Background Cast room procedures can be a source of anxiety for children. Various techniques, including music therapy, have been evaluated as a way to ease this anxiety. The use of iPads as a form of distraction during cast room procedures has not previously been evaluated and was the purpose of the current study. Methods 146 children and adolescents who underwent cast room procedures during June- August 2015 were randomly assigned to one of three groups: no-iPad, iPad with video, or iPad with game. Patient heart rates were measured using a pulse oximeter in the waiting room, before the procedure, during the procedure, and after the procedure. Mean values for each group were calculated at each time interval and compared both between groups and within groups over time. Results There were no significant differences in baseline (waiting room) heart rate between the no-iPad and iPad groups. When compared with the no-iPad group, there was a trend toward decreased heart rate in the video group (p=0.13) and a significant increase in heart rate in the game group (p=0.026) before the procedure. There were no significant decreases in heart rate within any of the groups when comparing the waiting room heart rates with the during procedure heart rates. There was a significant difference between the no-iPad and video groups (p=0.047) when comparing the change in heart rate from baseline to before the procedure, with a decreased heart rate observed in the video group. Conclusions The results of this study show a significant decrease in heart rate when transitioning from the waiting room to the cast room while watching videos on the iPad. iPad-based video delivery appears to decrease anxiety prior to cast room procedures. iPad-based game play is difficult to assess as elevations in heart rate prior to the procedure are presumed to be related to game play and confound the observed effect it may have on anxiety related to the procedure. PMID:27528849

A Heart Rate Analysis of Developmental Change in Feedback Processing and Rule Shifting from Childhood to Early Adulthood

ERIC Educational Resources Information Center

Crone, Eveline A.; Somsen, Riek J. M.; Zanolie, Kiki; Van der Molen, Maurits W.

2006-01-01

Over the course of development, the ability to switch between different tasks on the basis of feedback cues increases profoundly, but the role of performance monitoring remains unclear. Heart rate indexes can provide critical information about how individuals monitor feedback cues indicating that performance should be adjusted. In this study,…

Development of Decision Making in School-Aged Children and Adolescents: Evidence from Heart Rate and Skin Conductance Analysis

ERIC Educational Resources Information Center

Crone, Eveline A.; van der Molen, Maurits W.

2007-01-01

Age differences in decision making indicate that children fail to anticipate outcomes of their decisions. Using heart rate and skin conductance analyses, we tested whether developmental changes in decision making are associated with (a) a failure to process outcomes of decisions, or (b) a failure to anticipate future outcomes of decisions.…

A centrally mediated prolonged hypotension produced by oxotremorine or pilocarpine

PubMed Central

Dage, R.C.

1979-01-01

1 Oxotremorine, methyloxotremorine, pilocarpine or arecoline were given intravenously to anaesthetized cats, dogs or rats, and intraperitoneally to conscious normotensive and spontaneously hypertensive rats, pretreated with doses of methylatropine that completely blocked peripheral muscarinic receptors, to ascertain their effects on blood pressure and heart rate. 2 Oxotremorine but not methyloxotremorine produced a prolonged hypotension in cats and dogs but not in rats. Heart rate was not changed. Pilocarpine, although less potent, produced an identical effect, whereas the effect of arecoline was short by comparison. The hypotensive effect of these drugs was reversed by atropine. 3 In dogs, oxotremorine produced a prolonged hypotension with no change in heart rate or cardiac output. 4 A decrease in spontaneous sympathetic nerve activity accompanied the hypotension in cats. Both effects were reversed by atropine but could be reinvoked by large doses of oxotremorine. 5 The oxotremorine-induced hypotension in cats was not altered by decerebration but was abolished by high cervical spinal section. 6 The results indicate that the prolonged hypotension elicited by oxotremorine is mediated by an action at muscarinic receptors in the brain stem resulting in a decrease in sympathetic nerve activity and peripheral resistance but not heart rate or cardiac output. PMID:760887

Is Psychopathology the Key to Understanding Why Some Children Become Aggressive When They Are Exposed to Violent Television Programming?

ERIC Educational Resources Information Center

Grimes, Tom; Bergen, Lori; Nichols, Kathie; Vernberg, Eric; Fonagy, Peter

2004-01-01

Children with diagnosed psychopathologies may experience aggravation of those illnesses with their exposure to media violence. Children with the most common, often undiagnosed, form of psychopathology--Disruptive Behavior Disorders (DBDs)--manifested changes in heart rate, heart vagal heart tone and other psychophysiological reactions to media…

Fatty acid utilization in pressure-overload hypertrophied rat hearts

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

Reibel, D.K.; O'Rourke, B.

1986-03-05

The authors have previously shown that the levels of total tissue coenzyme A and carnitine are reduced in hypertrophied hearts of rats subjected to aortic constriction. It was therefore of interest to determine if these changes were associated with alterations in fatty acid oxidation by the hypertrophied myocardium. Hearts were excised from sham-operated and aortic-constricted rats and perfused at 10 cm H/sub 2/O left atrial filling pressure with a ventricular afterload of 80 cm of H/sub 2/O with buffer containing 1.2 mM /sup 14/C-linoleate. Heart rate and peak systolic pressure were not different in control and hypertrophied hearts. /sup 14/CO/submore » 2/ production was linear in both groups of hearts between 10 and 30 minutes of perfusion. The rate of fatty acid oxidation determined by /sup 14/CO/sub 2/ production during this time was 0.728 +/- 0.06 ..mu..moles/min/g dry in control hearts and 0.710 +/- 0.02 ..mu..moles/min/g dry in hypertrophied hearts. Comparable rates of fatty acid oxidation were associated with comparable rates of O/sub 2/ consumption in the two groups of hearts (39.06 +/- 3.50 and 36.78 +/- 2.39 ..mu..moles/g dry/min for control and hypertrophied hearts, respectively). The data indicate that the ability of the hypertrophied heart to oxidize fatty acids under these perfusion conditions is not impaired in spite of significant reductions in tissue levels of coenzyme A and carnitine.« less

[Crataegus Special Extract WS 1442 in NYHA II heart failure. A placebo controlled randomized double-blind study].

PubMed

Leuchtgens, H

1993-07-20

In 30 patients with stage NYHA II cardiac insufficiency, a placebo-controlled randomized double-blind study was carried out to determine the efficacy of the Crataegus special extract WS 1442. Treatment duration was 8 weeks, and the substance was administered at a dose of 1 capsule taken twice a day. The main target parameters were alteration in the pressure-x-rate product (PRP) under standardised loading on a bicycle ergometer, and a score of subjective improvement of complaints elicited by a questionnaire. Secondary parameters were exercise tolerance and the change in heart rate and arterial blood pressure. The active substance group showed a statistically significant advantage over placebo in terms of changes in PRP (at a load of 50 W) and the score, but also in the secondary parameter heart rate. In both groups, systolic and diastolic blood pressure was mildly reduced. No adverse reactions occurred.

Heart-rate sensitive optical coherence angiography for measuring vascular changes due to posttraumatic brain injury in mice

NASA Astrophysics Data System (ADS)

Tremoleda, Jordi L.; Alvarez, Karl; Aden, Abdirahman; Donnan, Robert; Michael-Titus, Adina T.; Tomlins, Peter H.

2017-12-01

Traumatic brain injury (TBI) results in direct vascular disruption, triggering edema, and reduction in cerebral blood flow. Therefore, understanding the pathophysiology of brain microcirculation following TBI is important for the development of effective therapies. Optical coherence angiography (OCA) is a promising tool for evaluating TBI in rodent models. We develop an approach to OCA that uses the heart-rate frequency to discriminate between static tissue and vasculature. This method operates on intensity data and is therefore not phase sensitive. Furthermore, it does not require spatial overlap of voxels and thus can be applied to pre-existing datasets for which oversampling may not have been explicitly considered. Heart-rate sensitive OCA was developed for dynamic assessment of mouse microvasculature post-TBI. Results show changes occurring at 5-min intervals within the first 50 min of injury.

Robust efficient estimation of heart rate pulse from video.

PubMed

Xu, Shuchang; Sun, Lingyun; Rohde, Gustavo Kunde

2014-04-01

We describe a simple but robust algorithm for estimating the heart rate pulse from video sequences containing human skin in real time. Based on a model of light interaction with human skin, we define the change of blood concentration due to arterial pulsation as a pixel quotient in log space, and successfully use the derived signal for computing the pulse heart rate. Various experiments with different cameras, different illumination condition, and different skin locations were conducted to demonstrate the effectiveness and robustness of the proposed algorithm. Examples computed with normal illumination show the algorithm is comparable with pulse oximeter devices both in accuracy and sensitivity.

Robust efficient estimation of heart rate pulse from video

PubMed Central

Xu, Shuchang; Sun, Lingyun; Rohde, Gustavo Kunde

2014-01-01

We describe a simple but robust algorithm for estimating the heart rate pulse from video sequences containing human skin in real time. Based on a model of light interaction with human skin, we define the change of blood concentration due to arterial pulsation as a pixel quotient in log space, and successfully use the derived signal for computing the pulse heart rate. Various experiments with different cameras, different illumination condition, and different skin locations were conducted to demonstrate the effectiveness and robustness of the proposed algorithm. Examples computed with normal illumination show the algorithm is comparable with pulse oximeter devices both in accuracy and sensitivity. PMID:24761294

Can a bank crisis break your heart?

PubMed Central

Stuckler, David; Meissner, Christopher M; King, Lawrence P

2008-01-01

Background To assess whether a banking system crisis increases short-term population cardiovascular mortality rates. Methods International, longitudinal multivariate regression analysis of cardiovascular disease mortality data from 1960 to 2002 Results A system-wide banking crisis increases population heart disease mortality rates by 6.4% (95% CI: 2.5% to 10.2%, p < 0.01) in high income countries, after controlling for economic change, macroeconomic instability, and population age and social distribution. The estimated effect is nearly four times as large in low income countries. Conclusion Banking crises are a significant determinant of short-term increases in heart disease mortality rates, and may have more severe consequences for developing countries. PMID:18197979

Fitting a single-phase model to the post-exercise changes in heart rate and oxygen uptake.

PubMed

Stupnicki, R; Gabryś, T; Szmatlan-Gabryś, U; Tomaszewski, P

2010-01-01

The kinetics of post-exercise heart rate (HR) and oxygen consumption (EPOC) was studied in 10 elite cyclists subjected to four laboratory cycle ergometer maximal exercises lasting 30, 90, 180 or 360 s. Heart rate and oxygen uptake (VO2) were recorded over a period of 6 min after the exercise. By applying the logit transformation to the recorded variables and relating them to the decimal logarithm of the recovery time, uniform single-phase courses of changes were shown for both variables in all subjects and exercises. This enabled computing half-recovery times (t(1/2)) for both variables. Half-time for VO2 negatively correlated with square root of exercise duration (within-subject r = -0.629, p < 0.001), the total post-exercise oxygen uptake till t(1/2) was thus constant irrespectively of exercise intensity. The method is simple and enables reliable comparisons of various modes of exercise with respect to the rate of recovery.

Impact of space weather on human heart rate during the years 2011-2013

NASA Astrophysics Data System (ADS)

Galata, E.; Ioannidou, S.; Papailiou, M.; Mavromichalaki, H.; Paravolidakis, K.; Kouremeti, M.; Rentifis, L.; Simantirakis, E.; Trachanas, K.

2017-08-01

During the last years a possible link between different levels of solar and geomagnetic disturbances and human physiological parameters is suggested by several published studies. In this work the examination of the potential association between heart rate variations and specific space weather activities was performed. A total of 482 individuals treated at Hippocratio General Hospital in Athens, the Cardiology clinics of Nikaia General Hospital in Piraeus and the Heraklion University Hospital in Crete, Greece, were assessed from July 2011 to April 2013. The heart rate of the individuals was recorded by a Holter monitor on a n hourly basis, while the hourly variations of the cosmic ray intensity measured by the Neutron Monitor Station of the Athens University and of the geomagnetic index Dst provided by the Kyoto Observatory were used. The ANalysis Of VAriance (ANOVA) and the Multiple Linear Regression analysis were used for analysis of these data. A statistically significant effect of both cosmic rays and geomagnetic activity on heart rate was observed, which may indicate that changes in space weather could be linked to heart rate variations.

Role of the autonomic nervous system in the control of heart rate and blood pressure in the defence reaction in conscious dogs.

PubMed

Federici, A; Rizzo, A; Cevese, A

1985-04-01

The present study was performed on conscious, chronically instrumented dogs, which underwent selective blockade of sympathetic adrenergic and vagal outflows. Excitements were performed on these animals in normal states (N), after chronic treatment with guanethidine, for sympathetic blockade (SB), after cold vagal blockade (VB), and after combined sympathetic and vagal blockade (SB + VB). Heart rate and arterial blood pressure were monitored in all the experiments, while a group of dogs was also tested with an electromagnetic flowmeter on the superior mesenteric artery. The role of the sympathetic and parasympathetic controls in the defence reaction was assumed from comparison of experiments performed in the presence or in the absence of each (or both) autonomic component(s). In the SB + VB condition, excitement was followed by sudden hypotension, without changes in heart rate. In VB experiments, a brief and transient hypotension appeared, followed by gradually developed hypertension, while heart rate progressively rose in about 5 s; there was no sudden increase in mesenteric vascular resistance, which contrasted with the very marked reaction in N experiments. Under vagal control alone (SB), the stimulus elicited prompt tachycardia and hypertension, followed by a period of moderately reduced blood pressure. We conclude that, while the defence reaction leads to a sudden fall of arterial blood pressure, in the absence of compensatory mechanisms, both branches of the autonomic nervous system play a protective role against hypotension. In addition, the modulation of the vagal outflow, leading to sudden changes in the heart performance, seems to be responsible for the initiation of the overall haemodynamic adjustments following excitements. The possibility that withdrawal of the parasympathetic outflow to the heart may raise arterial blood pressure was verified in a special experiment in which artificial vagal stimulation in a conscious (vagal blocked) dog, was turned off for brief periods, before and after guanethidine. This led to changes in blood pressure and heart rate very similar to those seen at the onset of the defence reaction, both in N and SB conditions.

Do former preterm infants remember and respond to neonatal intensive care unit noise?

PubMed

Barreto, Edwin D; Morris, Brenda H; Philbin, M Kathleen; Gray, Lincoln C; Lasky, Robert E

2006-11-01

Previous studies have shown that 4-month-old infants have a decrease in heart rate, a component of the orienting reflex, in response to interesting auditory stimuli and an increase in heart rate to aversive auditory stimuli. To compare the heart rate responses of former preterm and term infants at 4-5 months corrected age to a recording of NICU noises. 13 former preterm infants and 17 full-term infants were presented NICU noise and another noise of similar level and frequency content in random order. Heart rate 10s prior to the stimulus and for 20s during the stimulus was analyzed. Group differences in second by second heart rate changes in response to the two noise stimuli were compared by analysis of covariance. Both the preterm and term newborns responded similarly to the NICU noise and the control noise. The preterm infants did not alter their heart rate in response to either stimulus. In contrast, the term infants displayed an orienting response to the second stimulus presented regardless of whether it was the NICU or control noise. Former preterm infants at 4-5 months corrected age have reduced responsiveness to auditory stimulation in comparison to 4- to 5-month-old term infants. Furthermore, they did not respond to the NICU noise as an aversive stimulus.

Effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness of female patients with metabolic syndrome.

PubMed

Kang, Seol-Jung; Kim, Eon-Ho; Ko, Kwang-Jun

2016-06-01

[Purpose] The purpose of this study was to investigate the effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness or female patients with metabolic syndrome. [Subjects and Methods] Subjects were randomly assigned to an exercise group (n=12) or a control group (n=11). Subjects in the exercise group performed aerobic exercise at 60-80% of maximum heart rate for 40 min 5 times a week for 12 weeks. The changes in metabolic syndrome risk factors, resting heart rate, physical fitness, and arterial stiffness were measured and analyzed before and after initiation of the exercise program to determine the effect of exercise. Arterial stiffness was assessed based on brachial-ankle pulse wave velocity (ba-PWV). [Results] Compared to the control group; The metabolic syndrome risk factors (weight, % body fat, waist circumference, systolic blood pressure, diastolic blood pressure, and HDL-Cholesterol) were significantly improved in the exercise: resting heart rate was significantly decreased; VO2max, muscle strength and muscle endurance were significantly increased; and ba-PWV was significantly decreased. [Conclusion] Aerobic exercise had beneficial effects on the resting heart rate, physical fitness, and arterial stiffness of patients with metabolic syndrome.

Dynamic neural networking as a basis for plasticity in the control of heart rate.

PubMed

Kember, G; Armour, J A; Zamir, M

2013-01-21

A model is proposed in which the relationship between individual neurons within a neural network is dynamically changing to the effect of providing a measure of "plasticity" in the control of heart rate. The neural network on which the model is based consists of three populations of neurons residing in the central nervous system, the intrathoracic extracardiac nervous system, and the intrinsic cardiac nervous system. This hierarchy of neural centers is used to challenge the classical view that the control of heart rate, a key clinical index, resides entirely in central neuronal command (spinal cord, medulla oblongata, and higher centers). Our results indicate that dynamic networking allows for the possibility of an interplay among the three populations of neurons to the effect of altering the order of control of heart rate among them. This interplay among the three levels of control allows for different neural pathways for the control of heart rate to emerge under different blood flow demands or disease conditions and, as such, it has significant clinical implications because current understanding and treatment of heart rate anomalies are based largely on a single level of control and on neurons acting in unison as a single entity rather than individually within a (plastically) interconnected network. Copyright © 2012 Elsevier Ltd. All rights reserved.

Reliability of psychophysiological responses across multiple motion sickness stimulation tests

NASA Technical Reports Server (NTRS)

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

1995-01-01

Although there is general agreement that a high degree of variability exists between subjects in their autonomic nervous system responses to motion sickness stimulation, very little evidence exists that examines the reproducibility of autonomic responses within subjects during motion sickness stimulation. Our objectives were to examine the reliability of autonomic responses and symptom levels across five testing occasions using the (1) final minute of testing, (2) change in autonomic response and the change in symptom level, and (3) strength of the relationship between the change in symptom level and the change in autonomic responses across the entire motion sickness test. The results indicate that, based on the final minute of testing, the autonomic responses of heart rate, blood volume pulse, and respiration rate are moderately stable across multiple tests. Changes in heart rate, blood volume pulse, respiration rate, and symptoms throughout the test duration are less stable across the tests. Finally, autonomic responses and symptom levels are significantly related across the entire motion sickness test.

Sexual dimorphism in the osmopressor response following water ingestion

PubMed Central

Mendonca, Goncalo V.; Teodósio, Carolina; Lucena, Rui; Pereira, Fernando D.

2016-01-01

There is conflicting evidence as to whether water drinking elicits a pressor response in healthy young adults. The inclusion of a variable number of women may have contributed to the discrepancies found in past research. Thus, we aimed at exploring whether the osmopressor response follows a sexually dimorphic pattern. In a randomized fashion, 31 healthy adults (16 men; 15 women, aged 18–40 years) ingested 50 and 500 ml of water before completing a resting protocol on two separate days. Arterial blood pressure, heart rate and spectral heart rate variability were measured in the seated position at pre- and post-25 min of water ingestion. Women responded to 500 ml of water with a greater proportion of change in diastolic and mean arterial pressure (MAP) (P<0.05). Conversely, the percent change in systolic blood pressure (SBP) and heart rate was not different between sexes after 500 ml of water. Overall, women demonstrated lower blood pressure, but higher resting heart rate compared with men (P<0.05). In contrast, heart rate variability was similar between sexes before and after ingesting either volume of water. There was a bradycardic effect of water and, irrespectively of sex; this was accompanied by increased high frequency power (HF) (P<0.05). We conclude that women display a greater magnitude of pressor response than men post-water ingestion. Accordingly, we provide direct evidence of sexual dimorphism in the haemodynamic response to water intake in young healthy adults. PMID:27129286

Sleep-mediated heart rate variability after bilateral carotid body tumor resection.

PubMed

Niemeijer, Nicolasine D; Corssmit, Eleonora P M; Reijntjes, Robert H A M; Lammers, Gert Jan; van Dijk, J Gert; Thijs, Roland D

2015-04-01

The carotid bodies are thought to play an important role in sleep-dependent autonomic changes. Patients who underwent resection of bilateral carotid body tumors have chronically attenuated baroreflex sensitivity. These subjects provide a unique opportunity to investigate the role of the baroreflex during sleep. One-night ambulatory polysomnography (PSG) recording. Participants' homes. Nine patients with bilateral carotid body tumor resection (bCBR) (four women, mean age 50.4 ± 7.2 years) and nine controls matched for age, gender, and body mass index. N/A. Sleep parameters were obtained from PSG. Heart rate (HR) and its variability were calculated using 30-s epochs. In bCBR patients, HR was slightly but not significantly increased during wake and all sleep stages. The effect of sleep on HR was similar for patients and controls. Low frequency (LF) power of the heart rate variability spectrum was significantly lower in bCBR patients in active wakefulness, sleep stage 1 and REM sleep. No differences were found between patients and controls for high frequency (HF) power and the LF/HF ratio. Bilateral carotid body tumor resection (bCBR) is associated with decreased low frequency power during sleep, suggesting impaired baroreflex function. Despite this, sleep-related heart rate changes were similar between bCBR patients and controls. These findings suggest that the effects of sleep on heart rate are predominantly generated through central, non-baroreflex mediated pathways. © 2015 Associated Professional Sleep Societies, LLC.

Measuring task-related changes in heart rate variability.

PubMed

Moses, Ziev B; Luecken, Linda J; Eason, James C

2007-01-01

Small beat-to-beat differences in heart rate are the result of dynamic control of the cardiovascular system by the sympathetic and parasympathetic nervous systems. Heart rate variability (HRV) has been positively correlated with both mental and physical health. While many studies measure HRV under rest conditions, few have measured HRV during stressful situations. We describe an experimental protocol designed to measure baseline, task, and recovery values of HRV as a function of three different types of stressors. These stressors involve an attention task, a cold pressor test, and a videotaped speech presentation. We found a measurable change in heart rate in participants (n=10) during each task (all p's < 0.05). The relative increase or decrease from pre-task heart rate was predicted by task (one-way ANOVA, p= 0.0001). Spectral analysis of HRV during the attention task revealed consistently decreased measures of both high (68+/-7%, mean+/-S.E.) and low (62+/-13%) frequency HRV components as compared to baseline. HRV spectra for the cold pressor and speech tasks revealed no consistent patterns of increase or decrease from baseline measurements. We also found no correlation in reactivity measures between any of our tasks. These findings suggest that each of the tasks in our experimental design elicits a different type of stress response in an individual. Our experimental approach may prove useful to biobehavioral researchers searching for factors that determine individual differences in responses to stress in daily life.

Homeostasis and biological rhythms in the rat during spaceflight

NASA Technical Reports Server (NTRS)

Fuller, C. A.

1985-01-01

The effects of microgravity on the physiological regulation of homeostatic systems is studied. The temperature and heart rate of rats exposed to seven days of microgravity and a 12:12 light/dark cycle are analyzed. A 24-hour nocturnal rhythmicity is observed in the control and in-flight heart rates and body temperatures. The preflight daytime body temperature was calculated as 37.2 + or - 0.03 C and in-flight as 37.4 + or 0.04 C; nighttime body temperature preflight daytime was determined as 38.0 + or - 0.02 C, and in-flight as 37.8 + or 0.06 C. The 24-hour mean heart rate was depressed from 412 + or - 3.3 bpm preflight to 373 + or - 2.4 bpm in-flight; this change is noted in both dark and light conditions. It is detected that microgravity alters the steady state regulation of heart rate and body temperature.

Modulation of heart rate and heart rate variability by n-3 long chain polyunsaturated fatty acids: Speculation on mechanism(s).

PubMed

Drewery, Merritt L; Spedale, Steven B; Lammi-Keefe, Carol J

2017-09-01

Heart rate (HR) and heart rate variability (HRV) are valuable markers of health. Although the underlying mechanism(s) are controversial, it is well documented that n-3 long chain polyunsaturated fatty acid (LCPUFA) intake improves HR and HRV in various populations. Autonomic modulation and/or alterations in cardiac electrophysiology are commonly cited as potential mechanisms responsible for these effects. This article reviews existing evidence for each and explores a separate mechanism which has not received much attention but has scientific merit. Based on presented evidence, it is proposed that n-3 LCPUFAs affect HR and HRV directly by autonomic modulation and indirectly by altering circulating factors, both dependently and independently of the autonomic nervous system. The evidence for changes in cardiac electrophysiology as the mechanism by which n-3 LCPUFAs affect HR and HRV needs strengthening. Copyright © 2017 Elsevier Ltd. All rights reserved.

Selective heart rate reduction with ivabradine slows ischaemia-induced electrophysiological changes and reduces ischaemia–reperfusion-induced ventricular arrhythmias

PubMed Central

Ng, Fu Siong; Shadi, Iqbal T.; Peters, Nicholas S.; Lyon, Alexander R.

2013-01-01

Heart rates during ischaemia and reperfusion are possible determinants of reperfusion arrhythmias. We used ivabradine, a selective If current inhibitor, to assess the effects of heart rate reduction (HRR) during ischaemia–reperfusion on reperfusion ventricular arrhythmias and assessed potential anti-arrhythmic mechanisms by optical mapping. Five groups of rat hearts were subjected to regional ischaemia by left anterior descending artery occlusion for 8 min followed by 10 min of reperfusion: (1) Control n = 10; (2) 1 μM of ivabradine perfusion n = 10; (3) 1 μM of ivabradine + 5 Hz atrial pacing throughout ischaemia–reperfusion n = 5; (4) 1 μM of ivabradine + 5 Hz pacing only at reperfusion; (5) 100 μM of ivabradine was used as a 1 ml bolus upon reperfusion. For optical mapping, 10 hearts (ivabradine n = 5; 5 Hz pacing n = 5) were subjected to global ischaemia whilst transmembrane voltage transients were recorded. Epicardial activation was mapped, and the rate of development of ischaemia-induced electrophysiological changes was assessed. HRR observed in the ivabradine group during both ischaemia (195 ± 11 bpm vs. control 272 ± 14 bpm, p < 0.05) and at reperfusion (168 ± 13 bpm vs. 276 ± 14 bpm, p < 0.05) was associated with reduced reperfusion ventricular fibrillation (VF) incidence (20% vs. 90%, p < 0.05). Pacing throughout ischaemia–reperfusion abolished the protective effects of ivabradine (100% VF), whereas pacing at reperfusion only partially attenuated this effect (40% VF). Ivabradine, given as a bolus at reperfusion, did not significantly affect VF incidence (80% VF). Optical mapping experiments showed a delay to ischaemia-induced conduction slowing (time to 50% conduction slowing: 10.2 ± 1.3 min vs. 5.1 ± 0.7 min, p < 0.05) and to loss of electrical excitability in ivabradine-perfused hearts (27.7 ± 4.3 min vs. 14.5 ± 0.6 min, p < 0.05). Ivabradine administered throughout ischaemia and reperfusion reduced reperfusion VF incidence through HRR. Heart rate during ischaemia is a major determinant of reperfusion arrhythmias. Heart rate at reperfusion alone was not a determinant of reperfusion VF, as neither a bolus of ivabradine nor pacing immediately prior to reperfusion significantly altered reperfusion VF incidence. This anti-arrhythmic effect of heart rate reduction during ischaemia may reflect slower development of ischaemia-induced electrophysiological changes. PMID:23402927

Metabolic circadian rhythms in embryonic turtles.

PubMed

Loudon, Fiona Kay; Spencer, Ricky-John; Strassmeyer, Alana; Harland, Karen

2013-07-01

Oviparous species are model organisms for investigating embryonic development of endogenous physiological circadian rhythms without the influence of maternal biorhythms. Recent studies have demonstrated that heart rates and metabolic rates of embryonic turtles are not constant or always maximal and can be altered in response to the presence of embryos at a more advanced stage of development within the nest. A first step in understanding the physiological mechanisms underpinning these responses in embryonic ectothermic organisms is to develop metabolic profiles (e.g., heart rate) at different temperatures throughout incubation. Heart beat and rhythmic patterns or changes in development may represent important signals or cues within a nest and may be vital to coordinate synchronous hatching well in advance of the final stages of incubation. We developed baseline embryonic heart-rate profiles of embryos of the short-necked Murray River turtle (Emydura macquarii) to determine the stage of embryogenesis that metabolic circadian rhythms become established, if at all. Eggs were incubated at constant temperatures (26°C and 30°C) and heart rates were monitored at 6-h intervals over 24 h every 7-11 days until hatching. Circadian heart rate rhythms were detected at the mid-gestation period and were maintained until hatching. Heart rates throughout the day varied by up to 20% over 24 h and were not related to time of day. This study demonstrated that endogenous metabolic circadian rhythms in developing embryos in turtle eggs establish earlier in embryogenesis than those documented in other vertebrate taxa during embryogenesis. Early establishment of circadian rhythms in heart rates may be critical for communication among embryos and synchrony in hatching and emergence from the nest.

Physiological and Behavioral Parameters of Infants' Categorization: Changes in Heart Rate and Duration of Examining across Trials

ERIC Educational Resources Information Center

Elsner, Birgit; Pauen, Sabina; Jeschonek, Susanna

2006-01-01

This report investigates the relations between duration of examining and heart rate (HR) across several trials of an object-examination task. A total of N= 20 11-month-olds were familiarized with a sequence of 10 different exemplars from the same global category (animals or furniture) before they received an exemplar from the contrasting category…

Physiological and Mood Changes Induced by Exercise Withdrawal

DTIC Science & Technology

2004-01-01

parasympathetic nervous system and a shift towards increased sympathetic activity (Dekker et al., 2000; Task Force of the European Society of Cardiology and...HR response will be important. HR is controlled by both the sympathetic and parasympathetic nervous systems . Heart rate variability (HRV) is a... sympathetic and parasympathetic nervous systems plays an important role in cardiovascular homeostasis. Heart rate variability has been used as an

Randomised controlled trial of thiopental for intubation in neonates

PubMed Central

Bhutada, A; Sahni, R; Rastogi, S; Wung, J

2000-01-01

AIMS—To determine the effects of premedication with thiopental on heart rate, blood pressure, and oxygen saturation during semi-elective nasotracheal intubation in neonates.
METHODS—A randomised, placebo controlled, non-blinded study design was used to study 30 neonates (mean birthweight 3.27 kg) requiring semi-elective nasotracheal intubation. The babies were randomly allocated to receive either 6 mg/kg of thiopental (study group) or an equivalent volume of physiological saline (control group) one minute before the start of the procedure. Six infants were intubated primarily and 24 were changed from orotracheal to a nasotracheal tube. The electrocardiogram, arterial pressure wave, and transcutaneous oxygen saturation were recorded continuously 10 minutes before, during, and 20 minutes after intubation. Minute by minute measurements of heart rate, heart rate variability, mean blood pressure (MBP) and transcutaneous oxygen saturation (SpO2) were computed. The differences for all of these between the baseline measurements and those made during and after intubation were determined. Differences in the measurements made in the study and the control groups were compared using Student's t test.
RESULTS—During intubation, heart rate increased to a greater degree (12.0 vs−0.5 beats per minute, p < 0.03) and MBP increased to a lesser degree (−2.9 vs 4.4 mm Hg; p < 0.002) in the infants who were premedicated with thiopental. After intubation only the changes in MBP differed significantly between the two groups (−3.8 vs 4.6 mm Hg; p < 0.001). There were no significant changes in the oxygen saturation between the two groups during or after intubation. The time taken for intubation was significantly shorter in the study group (p < 0.04).
CONCLUSIONS—The heart rate and blood pressure of infants who are premedicated with thiopental are maintained nearer to baseline values than those of similar infants who receive no premedication. Whether this lessening of the acute drop in the heart rate and increase in blood pressure typically seen during intubation of unmedicated infants is associated with long term advantages to the infants remains to be determined.

 PMID:10634839

The Affordable Care Act Medicaid Expansion Correlated With Increased Heart Transplant Listings In African-Americans But Not Hispanics Or Caucasians

PubMed Central

Breathett, Khadijah; Allen, Larry A.; Helmkamp, Laura; Colborn, Kathryn; Daugherty, Stacie L.; Khazanie, Prateeti; Lindrooth, Richard; Peterson, Pamela

2016-01-01

Objectives The aim of this study was to determine if the Affordable Care Act (ACA) Medicaid Expansion was associated with increased census-adjusted heart transplant listing rates for racial/ethnic minorities. Background Underinsurance limits access to transplants, especially among racial/ethnic minorities. Changes in racial/ethnic listing rates post the ACA Medicaid Expansion are unknown. Methods Using the Scientific Registry of Transplant Recipients, we analyzed 5,651 patients from early adopter states (implemented ACA Medicaid Expansion by 1/2014) and 4,769 patients from non-adopter states (no implementation during study period) from 2012–2015. Piecewise linear models, stratified by race/ethnicity, were fit to monthly census-adjusted rates of heart transplant listings before and after 1/2014. Results A significant 30% increase in the rate of heart transplant listings for African-Americans in early adopter states occurred immediately following the ACA Medicaid Expansion on 1/1/2014 [pre 0.15 to post 0.20/100,000, increase 0.05/100,000 (95%Confidence Interval (CI): 0.01,0.08)]; in contrast, the rates for African-Americans in non-adopter states remained constant [pre and post 0.15/100,000, increase 0.006/100,000 (95%CI: −0.03,0.04)]. Hispanics experienced an opposite trend, with no significant change in early adopter states [pre 0.03 to post 0.04/100,000, increase 0.01/100,000 (95%CI: −0.004,0.02)] and a significant increase in non-adopter states [pre 0.03 to post 0.05/100,000, increase 0.02/100,000 (95%CI: 0.002,0.03)]. There were no significant changes in listing rates among Caucasians in either early adopter or non-adopter states. Conclusions Implementation of the ACA Medicaid Expansion was associated with increased heart transplant listings in African-Americans but not Hispanics or Caucasians. Broadening of the ACA in states with large African-American populations may reduce disparities in heart transplant listings. PMID:28109783

The Affordable Care Act Medicaid Expansion Correlated With Increased Heart Transplant Listings in African-Americans But Not Hispanics or Caucasians.

PubMed

Breathett, Khadijah; Allen, Larry A; Helmkamp, Laura; Colborn, Kathryn; Daugherty, Stacie L; Khazanie, Prateeti; Lindrooth, Richard; Peterson, Pamela N

2017-02-01

The aim of this study was to determine if the Affordable Care Act (ACA) Medicaid Expansion was associated with increased census-adjusted heart transplant listing rates for racial/ethnic minorities. Underinsurance limits access to transplants, especially among racial/ethnic minorities. Changes in racial/ethnic listing rates post-ACA Medicaid Expansion are unknown. Using the Scientific Registry of Transplant Recipients, we analyzed 5,651 patients from early adopter states (implemented the ACA Medicaid Expansion by January 2014) and 4,769 patients from non-adopter states (no implementation during the study period) from 2012 to 2015. Piecewise linear models, stratified according to race/ethnicity, were fit to monthly census-adjusted rates of heart transplant listings before and after January 2014. A significant 30% increase in the rate of heart transplant listings for African-American patients in early adopter states occurred immediately after the ACA Medicaid Expansion on January 1, 2014 (before 0.15 to after 0.20/100,000; increase 0.05/100,000; 95% confidence interval [CI]: 0.01 to 0.08); in contrast, the rates for African-American patients in non-adopter states remained constant (before and after 0.15/100,000; increase 0.006/100,000; 95% CI: -0.03 to 0.04). Hispanic patients experienced an opposite trend, with no significant change in early adopter states (before 0.03 to after 0.04/100,000; increase 0.01/100,000; 95% CI: -0.004 to 0.02) and a significant increase in non-adopter states (before 0.03 to after 0.05/100,000; increase 0.02/100,000; 95% CI: 0.002 to 0.03). There were no significant changes in listing rates among Caucasian patients in either early adopter states or non-adopter states. Implementation of the ACA Medicaid Expansion was associated with increased heart transplant listings in African-American patients but not in Hispanic or Caucasian patients. Broadening of the ACA in states with large African-American populations may reduce disparities in heart transplant listings. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Guided imagery, anxiety, heart rate, and heart rate variability during centrifuge training.

PubMed

Jing, Xiaolu; Wu, Ping; Liu, Fang; Wu, Bin; Miao, Danmin

2011-02-01

Centrifuge training is an important method of improving the hypergravity tolerance of pilots, cosmonauts, and Chinese astronauts. However, the concomitants of tension or anxiety often impede training. Guided imagery (GI), a mind-body relaxation technique, provides a behavioral and cognitive means whereby individuals are able to exert control over the focus of attention. This study aims to investigate the immediate effects of GI for reducing stress in centrifuge training. There were 12 healthy young men who were randomly assigned to a GI group or music group. We measured changes in heart rate during centrifuge training, in heart rate variability before and after centrifuge training, and also evaluated relaxation and anxiety in three phases: before intervention, after intervention, and following centrifuge training. The change in the pattern of anxiety was different in the two groups over the three phases. Anxiety (measured by State Anxiety Inventory) in the GI group changed from 31.7 +/- 5.9 to 26.8 +/- 2.6 and 27.8 +/- 4.1, whereas for the music group this changed from 32.2 +/- 7.6 to 31.2 +/- 8.3 and 26.8 +/- 6.8. During centrifuge training, the maximal HR for the GI group (101.2 +/- 8.8) was lower than that of the music group (123.0 +/- 19.1). In addition GI showed a decrease in low frequency (LF, 0.04-0.15 Hz) components and an increase in high frequency (HF, 0.15-0.4 Hz) components before and after centrifuge training. GI was capable of decreasing tension, anxiety, and sympathetic nervous system activity pre- or post-centrifugation.

Baseline Hemodynamics and Response to Contrast Media During Diagnostic Cardiac Catheterization Predict Adverse Events in Heart Failure Patients.

PubMed

Denardo, Scott J; Vock, David M; Schmalfuss, Carsten M; Young, Gregory D; Tcheng, James E; O'Connor, Christopher M

2016-07-01

Contrast media administered during cardiac catheterization can affect hemodynamic variables. However, little is documented about the effects of contrast on hemodynamics in heart failure patients or the prognostic value of baseline and changes in hemodynamics for predicting subsequent adverse events. In this prospective study of 150 heart failure patients, we measured hemodynamics at baseline and after administration of iodixanol or iopamidol contrast. One-year Kaplan-Meier estimates of adverse event-free survival (death, heart failure hospitalization, and rehospitalization) were generated, grouping patients by baseline measures of pulmonary capillary wedge pressure (PCWP) and cardiac index (CI), and by changes in those measures after contrast administration. We used Cox proportional hazards modeling to assess sequentially adding baseline PCWP and change in CI to 5 validated risk models (Seattle Heart Failure Score, ESCAPE [Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness], CHARM [Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity], CORONA [Controlled Rosuvastatin Multinational Trial in Heart Failure], and MAGGIC [Meta-Analysis Global Group in Chronic Heart Failure]). Median contrast volume was 109 mL. Both contrast media caused similarly small but statistically significant changes in most hemodynamic variables. There were 39 adverse events (26.0%). Adverse event rates increased using the composite metric of baseline PCWP and change in CI (P<0.01); elevated baseline PCWP and decreased CI after contrast correlated with the poorest prognosis. Adding both baseline PCWP and change in CI to the 5 risk models universally improved their predictive value (P≤0.02). In heart failure patients, the administration of contrast causes small but significant changes in hemodynamics. Calculating baseline PCWP with change in CI after contrast predicts adverse events and increases the predictive value of existing models. Patients with elevated baseline PCWP and decreased CI after contrast merit greatest concern. © 2016 American Heart Association, Inc.

Dissociation of Calcium Transients and Force Development following a Change in Stimulation Frequency in Isolated Rabbit Myocardium.

PubMed

Haizlip, Kaylan M; Milani-Nejad, Nima; Brunello, Lucia; Varian, Kenneth D; Slabaugh, Jessica L; Walton, Shane D; Gyorke, Sandor; Davis, Jonathan P; Biesiadecki, Brandon J; Janssen, Paul M L

2015-01-01

As the heart transitions from one exercise intensity to another, changes in cardiac output occur, which are modulated by alterations in force development and calcium handling. Although the steady-state force-calcium relationship at various heart rates is well investigated, regulation of these processes during transitions in heart rate is poorly understood. In isolated right ventricular muscle preparations from the rabbit, we investigated the beat-to-beat alterations in force and calcium during the transition from one stimulation frequency to another, using contractile assessments and confocal microscopy. We show that a change in steady-state conditions occurs in multiple phases: a rapid phase, which is characterized by a fast change in force production mirrored by a change in calcium transient amplitude, and a slow phase, which follows the rapid phase and occurs as the muscle proceeds to stabilize at the new frequency. This second/late phase is characterized by a quantitative dissociation between the calcium transient amplitude and developed force. Twitch timing kinetics, such as time to peak tension and 50% relaxation rate, reached steady-state well before force development and calcium transient amplitude. The dynamic relationship between force and calcium upon a switch in stimulation frequency unveils the dynamic involvement of myofilament-based properties in frequency-dependent activation.

Impact of a comprehensive smoke-free law following a partial smoke-free law on incidence of heart attacks at a rural community hospital.

PubMed

Johnson, Eric L; Beal, James R

2013-03-01

Secondhand smoking (passive smoking) is associated with many negative health effects, primarily respiratory and cardiovascular diseases. Approximately, 46,000 deaths from cardiovascular disease are associated with secondhand smoke exposure annually in the United States, which is roughly 150 deaths in North Dakota. Studies show that passage of smoke-free laws at the community level can reduce the incidence of heart attack. We conducted a retrospective review of electronic medical records of patients admitted for heart attacks 4 months prior (April 15, 2010 through August 14, 2010) to implementation of the smoke-free ordinance and 4 months following (August 15, 2010 through December 14, 2010) implementation of the comprehensive smoke-free ordinance in Grand Forks, ND, United States. We found an association between the heart attack rate and implementation of the comprehensive smoke-free law. The heart attack rate prior to the ban was 0.5% (83/16,702) compared with 0.3% (63/18,513) after the ban (p = .023). Thus, the rate of heart attacks decreased 30.6% and number of heart attack admissions decreased 24.1%, from 83 to 63, after implementation of a comprehensive smoke-free law. We found an implementation of the comprehensive smoke-free law was associated with a decrease in the heart attack rate. The heart attack rate decreased 30.6%. Our finding was similar to previous community level smoke-free law implementation studies and notable for the change going from a partial smoke-free law to a comprehensive smoke-free law.

Reorganization of the brain and heart rhythm during autogenic meditation

PubMed Central

Kim, Dae-Keun; Rhee, Jyoo-Hi; Kang, Seung Wan

2014-01-01

The underlying changes in heart coherence that are associated with reported EEG changes in response to meditation have been explored. We measured EEG and heart rate variability (HRV) before and during autogenic meditation. Fourteen subjects participated in the study. Heart coherence scores were significantly increased during meditation compared to the baseline. We found near significant decrease in high beta absolute power, increase in alpha relative power and significant increases in lower (alpha) and higher (above beta) band coherence during 3~min epochs of heart coherent meditation compared to 3~min epochs of heart non-coherence at baseline. The coherence and relative power increase in alpha band and absolute power decrease in high beta band could reflect relaxation state during the heart coherent meditation. The coherence increase in the higher (above beta) band could reflect cortico-cortical local integration and thereby affect cognitive reorganization, simultaneously with relaxation. Further research is still needed for a confirmation of heart coherence as a simple window for the meditative state. PMID:24454283

Reorganization of the brain and heart rhythm during autogenic meditation.

PubMed

Kim, Dae-Keun; Rhee, Jyoo-Hi; Kang, Seung Wan

2014-01-13

The underlying changes in heart coherence that are associated with reported EEG changes in response to meditation have been explored. We measured EEG and heart rate variability (HRV) before and during autogenic meditation. Fourteen subjects participated in the study. Heart coherence scores were significantly increased during meditation compared to the baseline. We found near significant decrease in high beta absolute power, increase in alpha relative power and significant increases in lower (alpha) and higher (above beta) band coherence during 3~min epochs of heart coherent meditation compared to 3~min epochs of heart non-coherence at baseline. The coherence and relative power increase in alpha band and absolute power decrease in high beta band could reflect relaxation state during the heart coherent meditation. The coherence increase in the higher (above beta) band could reflect cortico-cortical local integration and thereby affect cognitive reorganization, simultaneously with relaxation. Further research is still needed for a confirmation of heart coherence as a simple window for the meditative state.

Pacing-induced chronic atrial fibrillation impairs sinus node function in dogs. Electrophysiological remodeling.

PubMed

Elvan, A; Wylie, K; Zipes, D P

1996-12-01

We assessed the effects of pacing-induced chronic atrial fibrillation (AF) on sinus node function, intra-atrial conduction, and atrial refractoriness. In 15 mongrel dogs (20 to 30 kg), AV nodal block was produced by radiofrequency catheter ablation, and a ventricular-inhibited (VVI) pacemaker (Minix 8330, Medtronic) was implanted and programmed to pace at 80 pulses per minute. In 11 of these dogs, right atrial endocardial pacing leads were connected to a pulse generator (Itrel 7432, Medtronic) and set at a rate of 20 Hz to induce AF. Corrected sinus node recovery time, P-wave duration, 24-hour Holter ECG to assess AF duration, maximal heart rate in response to isoproterenol (10 micrograms/min), intrinsic heart rate after administration of atropine (0.04 mg/kg) and propranolol (0.1 mg/kg), and atrial effective refractory periods (ERPs) were obtained at baseline (EPS-1) and after 2 to 6 weeks (EPS-2) of VVI pacing alone (n = 4) or VVI pacing and rapid atrial pacing (n = 11). At EPS-2, corrected sinus node recovery time and P-wave duration were prolonged, maximal heart rate and intrinsic heart rate were decreased, atrial ERPs were shortened, and the duration of AF was increased significantly compared with EPS-1. These changes partially reversed toward baseline 1 week after conversion to sinus rhythm. Sinus node function and AF inducibility observed in the control dogs that underwent ventricular pacing alone (n = 4) did not change. Pacing-induced chronic AF induces sinus node dysfunction, prolongs intra-atrial conduction time, shortens atrial refractoriness, and perpetuates AF, changes that reverse gradually after termination of AF.

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

PubMed

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

2007-01-01

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

Female Listeners' Autonomic Responses to Dramatic Shifts Between Loud and Soft Music/Sound Passages: A Study of Heavy Metal Songs.

PubMed

Cheng, Tzu-Han; Tsai, Chen-Gia

2016-01-01

Although music and the emotion it conveys unfold over time, little is known about how listeners respond to shifts in musical emotions. A special technique in heavy metal music utilizes dramatic shifts between loud and soft passages. Loud passages are penetrated by distorted sounds conveying aggression, whereas soft passages are often characterized by a clean, calm singing voice and light accompaniment. The present study used heavy metal songs and soft sea sounds to examine how female listeners' respiration rates and heart rates responded to the arousal changes associated with auditory stimuli. The high-frequency power of heart rate variability (HF-HRV) was used to assess cardiac parasympathetic activity. The results showed that the soft passages of heavy metal songs and soft sea sounds expressed lower arousal and induced significantly higher HF-HRVs than the loud passages of heavy metal songs. Listeners' respiration rate was determined by the arousal level of the present music passage, whereas the heart rate was dependent on both the present and preceding passages. Compared with soft sea sounds, the loud music passage led to greater deceleration of the heart rate at the beginning of the following soft music passage. The sea sounds delayed the heart rate acceleration evoked by the following loud music passage. The data provide evidence that sound-induced parasympathetic activity affects listeners' heart rate in response to the following music passage. These findings have potential implications for future research on the temporal dynamics of musical emotions.

Tolazoline decreases survival time during microwave-induced lethal heat stress in anesthetized rats

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

Jauchem, J.R.; Chang, K.S.; Frei, M.R.

1996-03-01

Effects of {alpha}-adrenergic antagonists have been studied during environmental heating but not during microwave-induced heating. Tolazoline may exert some of its effects via {alpha}-adrenergic blockade. In the present study, ketamine-anesthetized Sprague-Dawley rats were exposed to 2450-MHz microwaves at an average power density of 60 mW/cm{sup 2} (whole-body specific absorption rate of approximately 14 W/kg) until lethal temperatures were attained. The effects of tolazoline (10 mg/kg body weight) on physiological responses (including changes in body temperature, heart rate, blood pressure, and respiratory rate) were examined. Survival time was significantly shorter in the tolazoline group than in saline-treated animals. In general, heartmore » rate and blood pressure responses were similar to those that occur during environmental heat stress. Heart rate, however, was significantly elevated in animals that received tolazoline, both before and during terminal microwave exposure. It is possible that changes associated with the elevated heart rate (e.g., less cardiac filling) in tolazoline-treated animals resulted in greater susceptibility to microwave-induced heating and the lower survival time. 47 refs., 3 figs., 2 tabs.« less

The effects of sustained manual pressure stimulation according to Vojta Therapy on heart rate variability.

PubMed

Opavsky, Jaroslav; Slachtova, Martina; Kutin, Miroslav; Hok, Pavel; Uhlir, Petr; Opavska, Hana; Hlustik, Petr

2018-05-23

The physiotherapeutic technique of Vojta reflex locomotion is often accompanied by various autonomic activity changes and unpleasant sensations. It is unknown whether these effects are specific to Vojta Therapy. Therefore, the aim of this study was to compare changes in cardiac autonomic control after Vojta reflex locomotion stimulation and after an appropriate sham stimulation. A total of 28 young healthy adults (20.4 - 25.7 years) were enrolled in this single-blind randomized cross-over study. Participants underwent two modes of 20-minute sustained manual pressure stimulation on the surface of the foot on two separate visits. One mode used manual pressure on the lateral heel, i.e., in a zone employed in the Vojta Therapy (active stimulation). The other mode used pressure on the lateral ankle (control), in an area not included among the active zones used by Vojta Therapy and whose activation does not evoke manifestations of reflex locomotion. Autonomic nervous system activity was evaluated using spectral analysis of heart rate variability before and after the intervention. The active stimulation was perceived as more unpleasant than the control stimulation. Heart rate variability parameters demonstrated almost identical autonomic responses after both stimulation types, showing either modest increase in parasympathetic activity, or increased heart rate variability with similar contribution of parasympathetic and sympathetic activity. The results demonstrate changes of cardiac autonomic control in both active and control stimulation, without evidence for a significant difference between the two.

Cardiorespiratory response to exercise after renal sympathetic denervation in patients with resistant hypertension.

PubMed

Ukena, Christian; Mahfoud, Felix; Kindermann, Ingrid; Barth, Christine; Lenski, Matthias; Kindermann, Michael; Brandt, Mathias C; Hoppe, Uta C; Krum, Henry; Esler, Murray; Sobotka, Paul A; Böhm, Michael

2011-09-06

This study sought to investigate the effects of interventional renal sympathetic denervation (RD) on cardiorespiratory response to exercise. RD reduces blood pressure at rest in patients with resistant hypertension. We enrolled 46 patients with therapy-resistant hypertension as extended investigation of the Symplicity HTN-2 (Renal Denervation With Uncontrolled Hypertension) trial. Thirty-seven patients underwent bilateral RD and 9 patients were assigned to the control group. Cardiopulmonary exercise tests were performed at baseline and 3-month follow-up. In the RD group, compared with baseline examination, blood pressure at rest and at maximum exercise after 3 months was significantly reduced by 31 ± 13/9 ± 13 mm Hg (p < 0.0001) and by 21 ± 20/5 ± 14 mm Hg (p < 0.0001), respectively. Achieved work rate increased by 5 ± 13 W (p = 0.029) whereas peak oxygen uptake remained unchanged. Blood pressure 2 min after exercise was significantly reduced by 29 ± 17/8 ± 15 mm Hg (p < 0.001 for systolic blood pressure; p = 0.002 for diastolic blood pressure). Heart rate at rest decreased after RD (4 ± 11 beats/min; p = 0.028), whereas maximum heart rate and heart rate increase during exercise were not different. Heart rate recovery improved significantly by 4 ± 7 beats/min after renal denervation (p = 0.009). In the control group, there were no significant changes in blood pressure, heart rate, maximum work rate, or ventilatory parameters after 3 months. RD reduces blood pressure during exercise without compromising chronotropic competence in patients with resistant hypertension. Heart rate at rest decreased and heart rate recovery improved after the procedure. (Renal Denervation With Uncontrolled Hypertension; [Symplicity HTN-2]; NCT00888433). Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

The effect of short duration transportation on serum cortisol response in alpacas (Llama pacos).

PubMed

Anderson, D E; Grubb, T; Silveira, F

1999-03-01

This research project evaluated the changes in serum cortisol in six male and six female alpacas in response to transportation of short duration. All alpacas were subjected to trailer transportation for 30 min. Serum samples were obtained prior to transportation, immediately after transportation, and after a 4-h recovery period. Heart rate was recorded at each time interval and observations of individual behavioural characteristics were recorded. Data were analysed using analysis of variance. Heart rate was not significantly changed by transportation stress. Serum cortisol concentration was significantly higher after transportation, but head returned to baseline concentration after the 4-h recovery period. Behavioural characteristics were not associated with changes in serum cortisol concentration.

Increase in hospital admission rates for heart failure in The Netherlands, 1980-1993.

PubMed Central

Reitsma, J. B.; Mosterd, A.; de Craen, A. J.; Koster, R. W.; van Capelle, F. J.; Grobbee, D. E.; Tijssen, J. G.

1996-01-01

OBJECTIVE: To study the trend in hospital admission rates for heart failure in the Netherlands from 1980 to 1993. DESIGN: All hospital admissions in the Netherlands with a principal discharge diagnosis of heart failure were analysed. In addition, individual records of heart failure patients from a subset of 7 hospitals were analysed to estimate the frequency and timing of readmissions. RESULTS: The total number of discharges for men increased from 7377 in 1980 to 13 022 in 1993, and for women from 7064 to 12 944. From 1980 through 1993 age adjusted discharge rates rose 48% for men and 40% for women. Age adjusted in-hospital mortality for heart failure decreased from 19% in 1980 to 15% in 1993. For all age groups in-hospital mortality for men was higher than for women. The mean length of hospital admissions in 1993 was 14.0 days for men and 16.4 days for women. A review of individual patient records from a 6.3% sample of all hospital admissions in the Netherlands indicated that within a 2 year period 18% of the heart failure patients were admitted more than once and 5% more than twice. CONCLUSIONS: For both men and women a pronounced increase in age adjusted discharge rates for heart failure was observed in the Netherlands from 1980 to 1993. Readmissions were a prominent feature among heart failure patients. Higher survival rates after acute myocardial infarction and the longer survival of patients with heart disease, including heart failure may have contributed to the observed increase. The importance of advances in diagnostic tools and of possible changes in admission policy remain uncertain. PMID:8944582

Effect of Noradrenergic Neurotoxin DSP-4 and Maprotiline on Heart Rate Spectral Components in Stressed and Resting Rats.

PubMed

Kur'yanova, E V; Zhukova, Yu D; Teplyi, D L

2017-07-01

The effects of intraperitoneal DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine, a noradrenergic neurotoxin) and maprotiline (an inhibitor of norepinephrine reuptake in synapses) on spectral components of heart rhythm variability were examined in outbred male and female rats treated with these agents in daily doses of 10 mg/kg for 3 days. At rest, DSP-4 elevated LF and VLF spectral components in male and female rats. Maprotiline elevated LF and VLF components in males at rest, increased HR and reduced all spectral components in resting females. Stress against the background of DSP-4 treatment sharply increased heart rate and reduced the powers of all spectral components (especially LF and VLF components). In maprotiline-treated rats, stress increased the powers of LF and VLF components. Thus, the central noradrenergic system participates in the formation of LF and VLF spectral components of heart rate variability at rest and especially during stressful stimulation, which can determine the phasic character of changes in the heart rate variability observed in stressed organism.

Post-exercise heart rate recovery independently predicts mortality risk in patients with chronic heart failure.

PubMed

Tang, Yi-Da; Dewland, Thomas A; Wencker, Detlef; Katz, Stuart D

2009-12-01

Post-exercise heart rate recovery (HRR) is an index of parasympathetic function associated with clinical outcomes in populations with and without documented coronary heart disease. Decreased parasympathetic activity is thought to be associated with disease progression in chronic heart failure (HF), but an independent association between post-exercise HRR and clinical outcomes among such patients has not been established. We measured HRR (calculated as the difference between heart rate at peak exercise and after 1 minute of recovery) in 202 HF subjects and recorded 17 mortality and 15 urgent transplantation outcome events over 624 days of follow-up. Reduced post-exercise HRR was independently associated with increased event risk after adjusting for other exercise-derived variables (peak oxygen uptake and change in minute ventilation per change in carbon dioxide production slope), for the Heart Failure Survival Score (adjusted HR 1.09 for 1 beat/min reduction, 95% CI 1.05-1.13, P < .0001), and the Seattle Heart Failure Model score (adjusted HR 1.08 for one beat/min reduction, 95% CI 1.05-1.12, P < .0001). Subjects in the lowest risk tertile based on post-exercise HRR (>or=30 beats/min) had low risk of events irrespective of the risk predicted by the survival scores. In a subgroup of 15 subjects, reduced post-exercise HRR was associated with increased serum markers of inflammation (interleukin-6, r = 0.58, P = .024; high-sensitivity C-reactive protein, r = 0.66, P = .007). Post-exercise HRR predicts mortality risk in patients with HF and provides prognostic information independent of previously described survival models. Pathophysiologic links between autonomic function and inflammation may be mediators of this association.

Microprocessor-based cardiotachometer

NASA Technical Reports Server (NTRS)

Crosier, W. G.; Donaldson, J. A.

1981-01-01

Instrument operates reliably even with stress-test electrocardiogram (ECG) signals subject to noise, baseline wandering, and amplitude change. It records heart rate from preamplified, single-lead ECG input signal and produces digital and analog heart-rate outputs which are fed elsewhere. Analog hardware processes ECG input signal, producing 10-ms pulse for each heartbeat. Microprocessor analyzes resulting pulse train, identifying irregular heartbeats and maintaining stable output during lead switching. Easily modified computer program provides analysis.

Indirect blood pressure and heart rate measured quickly without observer bias using a semi-automatic machine (auto-manometer)--response to isometric exercise in normal healthy males and its modification by beta-adrenoceptor blockade.

PubMed Central

Nyberg, G

1977-01-01

1 In a double-blind crossover study, six volunteers performed sustained handgrip at 50% of maximal voluntary contraction before and 90 min following oral administration of 0.25 and 100 mg metoprolol tartrate, a beta1 selective adrenoceptor blocking agent. Blood pressure and heart rate were measured with the Auto-Manometer, an electronic semi-automatic device based on the principles of the London School of Hygiene and Tropical Medicine sphygmomanometer. It eliminates observer and digital bias completely, and also records heart rate at the same time as blood pressure is recorded. 2 Resting heart rate fell 15% after 25 mg, 21% after 100 mg and was unchanged after placebo. Systolic blood pressure fell 6% on both doses and was unchanged on placebo. Diastolic pressure did not change with any of the doses. 3 At 1 min of handgrip, heart rate was significantly lower after 25 and 100 mg than before drug or after placebo. There was no difference between the blood pressure levels attained before or after any of the dose levels. The rise of heart rate tended to be somewhat dampened after 100 mg only. The rise in blood pressure was unchanged after any dose compared with before. Images Figure 1 PMID:901695

Cardiovascular and respiratory dynamics during normal and pathological sleep

NASA Astrophysics Data System (ADS)

Penzel, Thomas; Wessel, Niels; Riedl, Maik; Kantelhardt, Jan W.; Rostig, Sven; Glos, Martin; Suhrbier, Alexander; Malberg, Hagen; Fietze, Ingo

2007-03-01

Sleep is an active and regulated process with restorative functions for physical and mental conditions. Based on recordings of brain waves and the analysis of characteristic patterns and waveforms it is possible to distinguish wakefulness and five sleep stages. Sleep and the sleep stages modulate autonomous nervous system functions such as body temperature, respiration, blood pressure, and heart rate. These functions consist of a sympathetic tone usually related to activation and to parasympathetic (or vagal) tone usually related to inhibition. Methods of statistical physics are used to analyze heart rate and respiration to detect changes of the autonomous nervous system during sleep. Detrended fluctuation analysis and synchronization analysis and their applications to heart rate and respiration during sleep in healthy subjects and patients with sleep disorders are presented. The observed changes can be used to distinguish sleep stages in healthy subjects as well as to differentiate normal and disturbed sleep on the basis of heart rate and respiration recordings without direct recording of brain waves. Of special interest are the cardiovascular consequences of disturbed sleep because they present a risk factor for cardiovascular disorders such as arterial hypertension, cardiac ischemia, sudden cardiac death, and stroke. New derived variables can help to find indicators for these health risks.

Effect of training mode on post-exercise heart rate recovery of trained cyclists.

PubMed

McDonald, Kelia G; Grote, Silvie; Shoepe, Todd C

2014-06-28

The sympathetic nervous system dominates the regulation of body functions during exercise. Therefore after exercise, the sympathetic nervous system withdraws and the parasympathetic nervous system helps the body return to a resting state. In the examination of this relationship, the purpose of this study was to compare recovery heart rates (HR) of anaerobically versus aerobically trained cyclists. With all values given as means ± SD, anaerobically trained track cyclists (n=10, age=25.9 ± 6.0 yrs, body mass=82.7 ± 7.1 kg, body fat=10.0 ± 6.3%) and aerobically trained road cyclists (n=15, age=39.9 ± 8.5 yrs, body mass=75.3 ± 9.9 kg, body fat=13.1 ± 4.5%) underwent a maximal oxygen uptake test. Heart rate recovery was examined on a relative basis using heart rate reserve as well as the absolute difference between maximum HR and each of two recovery HRs. The post-exercise change in HR at minute one for the track cyclists and road cyclists respectively were 22 ± 8 bpm and 25 ± 12 bpm. At minute two, the mean drop for track cyclists was significantly (p<0.05) greater than the road cyclists (52 ± 15 bpm and 64 ± 11 bpm). Training mode showed statistically significant effects on the speed of heart rate recovery in trained cyclists. Greater variability in recovery heart rate at minute two versus minute one suggests that the heart rate should be monitored longer than one minute of recovery for a better analysis of post-exercise autonomic shift.

Functional role of diverse changes in sympathetic nerve activity in regulating arterial pressure during REM sleep.

PubMed

Yoshimoto, Misa; Yoshida, Ikue; Miki, Kenju

2011-08-01

This study aimed to investigate whether REM sleep evoked diverse changes in sympathetic outflows and, if so, to elucidate why REM sleep evokes diverse changes in sympathetic outflows. Male Wistar rats were chronically implanted with electrodes to measure renal (RSNA) and lumbar sympathetic nerve activity (LSNA), electroencephalogram, electromyogram, and electrocardiogram, and catheters to measure systemic arterial and central venous pressure; these parameters were measured simultaneously and continuously during the sleep-awake cycle in the same rat. REM sleep resulted in a step reduction in RNSA by 36.1% ± 2.7% (P < 0.05), while LSNA increased in a step manner by 15.3% ± 2% (P < 0.05) relative to the NREM level. Systemic arterial pressure increased gradually (P < 0.05), while heart rate decreased in a step manner (P < 0.05) during REM sleep. In contrast to REM sleep, RSNA, LSNA, systemic arterial pressure, and heart rate increased in a unidirectional manner associated with increases in physical activity levels in the order from NREM sleep, quiet awake, moving, and grooming state. Thus, the relationship between RSNA vs. LSNA and systemic arterial pressure vs. heart rate observed during REM sleep was dissociated compared with that obtained during the other behavioral states. It is suggested that the diverse changes in sympathetic outflows during REM sleep may be needed to increase systemic arterial pressure by balancing vascular resistance between muscles and vegetative organs without depending on the heart.

[Cardiovascular recovery during intermittent exercise in highly-adherent partic pants with hypertension and type 2 diabetes mellitus].

PubMed

Cano-Montoya, Johnattan; Álvarez, Cristian; Martínez, Cristian; Salas, Andrés; Sade, Farid; Ramírez-Campillo, Rodrigo

2016-09-01

Despite the evidence supporting metabolic benefits of high intensity interval exercise (HIIT), there is little information about the cardiovascular response to this type of exercise in patients with type 2 diabetes (T2D) and hypertension (HTA). To analyze the changes in heart rate at rest, at the onset and at the end of each interval of training, after twelve weeks of a HIIT program in T2D and HTA patients. Twenty-three participants with T2D and HTA (20 women) participated in a controlled HIIT program. Fourteen participants attended 90% of more session of exercise and were considered as adherent. Adherent and non-adherent participants had similar body mass index (BMI), and blood pressure. A “1x2x10” (work: rest-time: intervals) HIIT exercise protocol was used both as a test and as training method during twelve weeks. The initial and finishing heart rate (HR) of each of the ten intervals before and after the intervention were measured. After twelve weeks of HIIT intervention, adherent participants had a significant reduction in the heart rate at the onset of exercise, and during intervals 4, 5, 8 and 10. A reduction in the final heart rate was observed during intervals 8 and 10. In the same participants the greatest magnitude of reduction, at the onset or end of exercise was approximately 10 beats/min. No significant changes in BMI, resting heart rate and blood pressure were observed. A HIIT program reduces the cardiovascular effort to a given work-load and improves cardiovascular recovery after exercise.

Depression and Heart Diseases: Leading Health Problems.

PubMed

Raič, Matea

2017-12-01

Depression is the most common psychiatric disorder in the world population and the most frequent mental disorder in a primary health care. Unrecognized and untreated depression is associated with a poor outcome of treated chronic diseases which co-exist with depression. Depression and cardiovascular diseases are bidirectional related conditions, risks are for each other, and they often co-exist. Depression is a common disorder in cardiovascular patients with a prevalence of 20% to 45%, which is much more frequent than in the general population. In cardiac patients with acute myocardial infarction, depression occurs three times more often than in the general population. Depression has a direct effect on the pathophysiological changes of various organ systems, changing the values of blood pressure, heart rate, vasomotor tone, vascular resistance, blood viscosity and plasma volume. The potential mechanism for developing heart disease in depressed patients includes hypothalamic-pituitary-adrenal gland dysfunction, increased proinflammatory and prothrombotic factor activity, reduced omega-3 fatty acids, reduced heart rate variability, smoking, physical inactivity, reduced mood, self-esteem and self-efficacy.

Effects of the Right Carotid Sinus Compression Technique on Blood Pressure and Heart Rate in Medicated Patients with Hypertension.

PubMed

Campón-Checkroun, Angélica María; Luceño-Mardones, Agustín; Riquelme, Inmaculada; Oliva-Pascual-Vaca, Jesús; Ricard, François; Oliva-Pascual-Vaca, Ángel

2018-05-07

To identify the immediate and middle-term effects of the right carotid sinus compression technique on blood pressure and heart rate in hypertensive patients. Randomized blinded experimental study. Primary health centers of Cáceres (Spain). Sixty-four medicated patients with hypertension were randomly assigned to an intervention group (n = 33) or to a control group (n = 31). In the intervention group a compression of the right carotid sinus was applied for 20 sec. In the control group, a placebo technique of placing hands on the radial styloid processes was performed. Blood pressure and heart rate were measured in both groups before the intervention (preintervention), immediately after the intervention, 5 min after the intervention, and 60 min after the intervention. The intervention group significantly decreased systolic and diastolic blood pressure and heart rate immediately after the intervention, with a large clinical effect; systolic blood pressure remained reduced 5 min after the intervention, and heart rate remained reduced 60 min after the intervention. No significant changes were observed in the control group. Right carotid sinus compression could be clinically useful for regulating acute hypertension.

Baroreflex modulation of muscle sympathetic nerve activity during cold pressor test in humans

NASA Technical Reports Server (NTRS)

Cui, Jian; Wilson, Thad E.; Crandall, Craig G.

2002-01-01

The purpose of this project was to test the hypothesis that baroreceptor modulation of muscle sympathetic nerve activity (MSNA) and heart rate is altered during the cold pressor test. Ten subjects were exposed to a cold pressor test by immersing a hand in ice water for 3 min while arterial blood pressure, heart rate, and MSNA were recorded. During the second and third minute of the cold pressor test, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.005) during the cold pressor test (-244.9 +/- 26.3 units x beat(-1) x mmHg(-1)) when compared with control conditions (-138.8 +/- 18.6 units x beat(-1) x mmHg(-1)), whereas no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that baroreceptors remain capable of modulating MSNA and heart rate during a cold pressor test; however, the sensitivity of baroreflex modulation of MSNA is elevated without altering the sensitivity of baroreflex control of heart rate.

The relationship between heart rate recovery and brain natruretic Peptide in patients with chest discomfort: a study for relationship between heart rate recovery and pre-exercise, post-exercise levels of brain natruretic Peptide in patients with normal systolic function and chest discomfort.

PubMed

Lee, Jae Eun; Kim, Bum Soo; Park, Wan; Huh, Jung Kwon; Kim, Byung Jin; Sung, Ki Chul; Kang, Jin Ho; Lee, Man Ho; Park, Jung Ro

2010-04-01

The correlation between brain natruretic peptide (BNP) level and cardiac autonomic function has been studied in type 2 diabetic patients. However, there is limited data from patients with normal systolic function. We evaluated the association between heart rate recovery (HRR) representing autonomic dysfunction and three plasma BNP levels: pre-exercise, post-exercise, and change during exercise in patients with normal systolic function. Subjects included 105 patients with chest pain and normal systolic function. HRR was defined as the difference between the peak heart rate and the rate measured two minutes after completion of a treadmill exercise test. We measured plasma BNP levels before exercise, 5 minutes after completion of exercise, and during exercise (absolute value of difference between pre- and post-exercise BNP levels). Patients with abnormal HRR values (

Effects of IV Acetaminophen on Core Body Temperature and Hemodynamic Responses in Febrile Critically Ill Adults: A Randomized Controlled Trial.

PubMed

Schell-Chaple, Hildy M; Liu, Kathleen D; Matthay, Michael A; Sessler, Daniel I; Puntillo, Kathleen A

2017-07-01

To determine the effects of IV acetaminophen on core body temperature, blood pressure, and heart rate in febrile critically ill patients. Randomized, double-blind, placebo-controlled clinical trial. Three adult ICUs at a large, urban, academic medical center. Forty critically ill adults with fever (core temperature, ≥ 38.3°C). An infusion of acetaminophen 1 g or saline placebo over 15 minutes. Core temperature and vital signs were measured at baseline and at 5-15-minute intervals for 4 hours after infusion of study drug. The primary outcome was time-weighted average core temperature adjusted for baseline temperature. Secondary outcomes included adjusted time-weighted average heart rate, blood pressure, and respiratory rate, along with changes-over-time for each. Baseline patient characteristics were similar in those given acetaminophen and placebo. Patients given acetaminophen had an adjusted time-weighted average temperature that was 0.47°C less than those given placebo (95% CI, -0.76 to -0.18; p = 0.002). The acetaminophen group had significantly lower adjusted time-weighted average systolic blood pressure (-17 mm Hg; 95% CI, -25 to -8; p < 0.001), mean arterial pressure (-7 mm Hg; 95% CI, -12 to -1; p = 0.02), and heart rate (-6 beats/min; 95% CI, -10 to -1; p = 0.03). Changes-over-time temperature, blood pressure, and heart rate outcomes were also significantly lower at 2 hours, but not at 4 hours. Among febrile critically ill adults, treatment with acetaminophen decreased temperature, blood pressure, and heart rate. IV acetaminophen thus produces modest fever reduction in critical care patients, along with clinically important reductions in blood pressure.

Effects of transcranial direct current stimulation on craving, heart-rate variability and prefrontal hemodynamics during smoking cue exposure.

PubMed

Kroczek, A M; Häußinger, F B; Rohe, T; Schneider, S; Plewnia, C; Batra, A; Fallgatter, A J; Ehlis, A-C

2016-11-01

Drug-related cue exposure elicits craving and risk for relapse during recovery. Transcranial direct current stimulation is a promising research tool and possible treatment for relapse prevention. Enhanced functional neuroconnectivity is discussed as a treatment target. The goal of this research was to examine whether transcranial direct current stimulation affected cortical hemodynamic indicators of functional connectivity, craving, and heart rate variability during smoking-related cue exposure in non-treatment-seeking smokers. In vivo smoking cue exposure supported by a 2mA transcranial direct current stimulation (anode: dorsolateral prefrontal cortex, cathode: orbitofrontal cortex; placebo-controlled, randomized, double-blind) in 29 (age: M=25, SD=5) German university students (smoking at least once a week). Cue reactivity was assessed on an autonomous (heart rate variability) and a subjective level (craving ratings). Functional near-infrared spectroscopy measured changes in the concentration of deoxygenated hemoglobin, and seed-based correlation analysis was used to quantify prefrontal connectivity of brain regions involved in cue reactivity. Cue exposure elicited increased subjective craving and heart rate variability changes in smokers. Connectivity between the orbitofrontal and dorsolateral prefrontal cortex was increased in subjects receiving verum compared to placebo stimulation (d=0.66). Hemodynamics in the left dorsolateral prefrontal cortex, however, increased in the group receiving sham stimulation (η 2 =0.140). Transcranial direct current stimulation did not significantly alter craving or heart rate variability during cue exposure. Prefrontal connectivity - between regions involved in the processing of reinforcement value and cognitive control - was increased by anodal transcranial direct current stimulation during smoking cue exposure. Possible clinical implications should be considered in future studies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effects of cognitive stimulation with a self-modeling video on time to exhaustion while running at maximal aerobic velocity: a pilot study.

PubMed

Hagin, Vincent; Gonzales, Benoît R; Groslambert, Alain

2015-04-01

This study assessed whether video self-modeling improves running performance and influences the rate of perceived exertion and heart rate response. Twelve men (M age=26.8 yr., SD=6; M body mass index=22.1 kg.m(-2), SD=1) performed a time to exhaustion running test at 100 percent maximal aerobic velocity while focusing on a video self-modeling loop to synchronize their stride. Compared to the control condition, there was a significant increase of time to exhaustion. Perceived exertion was lower also, but there was no significant change in mean heart rate. In conclusion, the video self-modeling used as a pacer apparently increased endurance by decreasing perceived exertion without affecting the heart rate.

Heart rate measurement based on a time-lapse image.

PubMed

Takano, Chihiro; Ohta, Yuji

2007-10-01

Using a time-lapse image acquired from a CCD camera, we developed a non-contact and non-invasive device, which could measure both the respiratory and pulse rate simultaneously. The time-lapse image of a part of the subject's skin was consecutively captured, and the changes in the average image brightness of the region of interest (ROI) were measured for 30s. The brightness data were processed by a series of operations of interpolation as follows a first-order derivative, a low pass filter of 2 Hz, and a sixth-order auto-regressive (AR) spectral analysis. Fourteen sound and healthy female subjects (22-27 years of age) participated in the experiments. Each subject was told to keep a relaxed seating posture with no physical restriction. At the same time, heart rate was measured by a pulse oximeter and respiratory rate was measured by a thermistor placed at the external naris. Using AR spectral analysis, two clear peaks could be detected at approximately 0.3 and 1.2 Hz. The peaks were thought to correspond to the respiratory rate and the heart rate. Correlation coefficients of 0.90 and 0.93 were obtained for the measurement of heart rate and respiratory rate, respectively.

Evaluation of heart rate variability indices using a real-time handheld remote ECG monitor.

PubMed

Singh, Swaroop S; Carlson, Barbara W; Hsiao, Henry S

2007-12-01

Studies on retrospective electrocardiogram (ECG) recordings of patients during cardiac arrest have shown significant changes in heart rate variability (HRV) indices prior to the onset of cardiac arrhythmia. The early detection of these changes in HRV indices increases the chances for a successful medical intervention by increasing the response time window. A portable, handheld remote ECG monitor designed in this research detects the QRS complex and calculates short-term HRV indices in real-time. The QRS detection of the ECG recordings of subjects from the MIT-Arrhythmia database yielded a mean sensitivity of 99.34% and a specificity of 99.31%. ECG recordings from normal subjects and subjects with congestive heart failure were used to identify the differences in HRV indices. An increase in heart rate, high-frequency spectral power (HFP), total spectral power, the ratio of HFP to low-frequency spectral power (LFP), and a decrease in root mean square sum of RR differences were observed. No difference was found on comparison of the standard deviation of normal to normal interval between adjacent R-waves, LFP, and very-low-frequency spectral power. Based on these, additional analytical calculations could be made to provide early warnings of impending cardiac conditions.

Heart Rate and Oxygen Uptake Kinetics in Type 2 Diabetes Patients - A Pilot Study on the Influence of Cardiovascular Medication on Regulatory Processes.

PubMed

Koschate, Jessica; Drescher, Uwe; Baum, Klaus; Brinkmann, Christian; Schiffer, Thorsten; Latsch, Joachim; Brixius, Klara; Hoffmann, Uwe

2017-05-01

The aim of this pilot study was to investigate whether there are differences in heart rate and oxygen uptake kinetics in type 2 diabetes patients, considering their cardiovascular medication. It was hypothesized that cardiovascular medication would affect heart rate and oxygen uptake kinetics and that this could be detected using a standardized exercise test. 18 subjects were tested for maximal oxygen uptake. Kinetics were measured in a single test session with standardized, randomized moderate-intensity work rate changes. Time series analysis was used to estimate kinetics. Greater maxima in cross-correlation functions indicate faster kinetics. 6 patients did not take any cardiovascular medication, 6 subjects took peripherally acting medication and 6 patients were treated with centrally acting medication. Maximum oxygen uptake was not significantly different between groups. Significant main effects were identified regarding differences in muscular oxygen uptake kinetics and heart rate kinetics. Muscular oxygen uptake kinetics were significantly faster than heart rate kinetics in the group with no cardiovascular medication (maximum in cross-correlation function of muscular oxygen uptake vs. heart rate; 0.32±0.08 vs. 0.25±0.06; p=0.001) and in the group taking peripherally acting medication (0.34±0.05 vs. 0.28±0.05; p=0.009) but not in the patients taking centrally acting medication (0.28±0.05 vs. 0.30±0.07; n.s.). It can be concluded that regulatory processes for the achievement of a similar maximal oxygen uptake are different between the groups. The used standardized test provided plausible results for heart rate and oxygen uptake kinetics in a single measurement session in this patient group. © Georg Thieme Verlag KG Stuttgart · New York.

RSV prophylaxis guideline changes and outcomes in children with congenital heart disease.

PubMed

Walpert, Adam S; Thomas, Ian D; Lowe, Merlin C; Seckeler, Michael D

2018-05-01

The aim of this study was to compare inpatient outcomes and costs for children with respiratory syncytial virus and congenital heart disease before and after the change in management guidelines for respiratory syncytial virus prophylaxis. Hospital discharge data from the Vizient (formerly University HealthSystem Consortium) were queried from October 2012 to June 2014 (Era 1) and July 2014 to April 2016 (Era 2) for patients aged <24 months with an any International Classification of Disease (ICD)-9 or ICD-10 code for congenital heart disease (745-747.49, Q20.0-Q26.4) and a primary or secondary admitting diagnosis of respiratory syncytial virus infection (079.6, J20.5), acute bronchiolitis due to respiratory syncytial virus (466.11, J21.0) or respiratory syncytial virus pneumonia (480.1, J12.1). This study is a review of a national administrative discharge database. Respiratory syncytial virus admissions were identified in 1269 patients aged <24 months with congenital heart disease, with 644 patients in Era 1 and 625 in Era 2. Patients 0-12 months old represented 83% of admissions. Prior to 2014, children aged 0-24 months with congenital heart disease were eligible to receive respiratory syncytial virus prophylaxis. Updated guidelines, published in 2014, restricted the recommendation to administer palivizumab respiratory syncytial virus prophylaxis to children with congenital heart disease only if they are ≤12 months old. The outcome measures are hospital length of stay, ICU admission rate, mortality, and direct costs. There was no change in length of stay, ICU admission rate, in-hospital mortality, or direct costs for children 13-24 months old with congenital heart disease after the change in guidelines. There were no deaths in 13-24 month olds, regardless of era. Our findings provide additional support for the new guideline recommendations to provide respiratory syncytial virus prophylaxis only for children ≤12 months old with congenital heart disease. © 2018 Wiley Periodicals, Inc.

Increased Regurgitant Flow Causes Endocardial Cushion Defects in an Avian Embryonic Model of Congenital Heart Disease

PubMed Central

Ford, Stephanie M; McPheeters, Matthew T; Wang, Yves T; Ma, Pei; Gu, Shi; Strainic, James; Snyder, Christopher; Rollins, Andrew M; Watanabe, Michiko; Jenkins, Michael W

2017-01-01

Background The relationship between changes in endocardial cushion and resultant congenital heart diseases (CHD) has yet to be established. It has been shown that increased regurgitant flow early in embryonic heart development leads to endocardial cushion defects, but it remains unclear how abnormal endocardial cushions during the looping stages might affect the fully septated heart. The goal of this study was to reproducibly alter blood flow in vivo and then quantify the resultant effects on morphology of endocardial cushions in the looping heart and on CHDs in the septated heart. Methods Optical pacing was applied to create regurgitant flow in embryonic hearts, and optical coherence tomography (OCT) was utilized to quantify regurgitation and morphology. Embryonic quail hearts were optically paced at 3 Hz (180bpm, well above intrinsic rate 60–110bpm) at stage 13 of development (3–4 wks human) for 5 min. Pacing fatigued the heart and led to at least 1 hr of increased regurgitant flow. Resultant morphological changes were quantified with OCT imaging at stage 19 (cardiac looping – 4–5 wks human) or stage 35 (4 chambered heart – 8 wks human). Results All paced embryos imaged at stage 19 displayed structural changes in cardiac cushions. The amount of regurgitant flow immediately after pacing was inversely correlated with cardiac cushion size 24-hrs post pacing (p-value < 0.01). The embryos with the most regurgitant flow and smallest cushions after pacing had a decreased survival rate at 8 days (p<0.05), indicating that those most severe endocardial cushion defects were lethal. Of the embryos that survived to stage 35, 17/18 exhibited CHDs including valve defects, ventricular septal defects, hypoplastic ventricles, and common AV canal. Conclusion The data illustrate a strong inverse relationship in which regurgitant flow precedes abnormal and smaller cardiac cushions, resulting in the development of CHDs. PMID:28211263

Mindfulness meditation in aphasia: A case report.

PubMed

Laures-Gore, Jacqueline; Marshall, Rebecca Shisler

2016-04-06

Despite the potential behavioral and neurological benefits of Mindfulness Meditation (MM), its use in treating stroke related communication disabilities appears to be underexplored. Specifically, aphasia, a language disorder resulting from stroke, may be amenable to the benefits of MM because of the observed attention problems often underlying the language symptoms. The current paper presents a case report of an adult with aphasia who was trained in MM. An adult with aphasia completed a five-day mindfulness training, and was assessed on measures of language, attention, and physiological measures of cortisol and heart rate variability. She completed four assessments: two baseline measures, immediately post training, and one week post training (maintenance). Overall, changes were observed in both psychophysiological measures (heart rate and heart rate variability) and behavioral measures (word productivity, phrase length, word generation, decreased impulsivity, and increased attention). Given the psychophysiological and behavioral changes observed in this individual, further exploration of the influence of MM in the treatment of post-stroke aphasia is warranted.

Acute effects of electromagnetic stimulation of the brain on cortical activity, cortical blood flow, blood pressure and heart rate in the cat: an evaluation of safety.

PubMed Central

Eyre, J A; Flecknell, P A; Kenyon, B R; Koh, T H; Miller, S

1990-01-01

The influence of repeated high intensity electromagnetic stimulation of the brain on cortical activity, cortical blood flow, blood pressure and heart rate has been investigated in the cat, to evaluate the safety of the method. The observations have been made in preparations under propofol anaesthesia before, during and after periods of anoxia. Electromagnetic stimulation of the brain evoked activity in descending motor pathways and was recorded by activity in the median nerve and by muscle twitches. Following repeated series of high intensity stimulation there were no systematic changes in somatosensory evoked potentials or background EEG, nor were there signs of epileptogenic activity during electromagnetic stimulation, before, during or after periods of anoxia. No systematic changes in cortical blood flow, blood pressure or heart rate were observed during electromagnetic stimulation, before or after periods of anoxia. In conclusion, no acute adverse consequences following electromagnetic stimulation in the normal and anoxic cat brain were demonstrated. PMID:2380732

Aortic baroreflex control of heart rate after 15 days of simulated microgravity exposure

NASA Technical Reports Server (NTRS)

Crandall, Craig G.; Engelke, Keith A.; Convertino, Victor A.; Raven, Peter B.

1994-01-01

To determine the effects of simulated microgravity on aortic baroreflex control of heart rate, we exposed seven male subjects to 15 days of bed rest in the 6 deg head-down position. The sensitivity of the aortic-cardiac baroreflex was determined during a steady-state phenylephrine-induced increase in mean arterial pressure combined with lower body negative pressure to counteract central venous pressure increases and neck pressure to offset the increased carotid sinus transmural pressure. The aortic-cardiac baroreflex gain was assessed by determining the ratio of the change in heart rate to the change in mean arterial pressure between baseline conditions and aortic baroreceptor-isolated conditions (i.e., phenylephrine + lower body negative pressure + neck pressure stage). Fifteen days of head-down tilt increased the gain of the aortic-cardiac baroreflex. Reductions in blood volume and/or maximal aerobic capacity may represent the underlying mechanism(s) responsible for increased aortic baroreflex responsiveness after exposure to a ground-based analogue of microgravity.

Ambulatory vital signs in the workup of pulmonary embolism using a standardized 3-minute walk test.

PubMed

Amin, Qamar; Perry, Jeffrey J; Stiell, Ian G; Mohapatra, Subhra; Alsadoon, Abdulaziz; Rodger, Marc

2015-05-01

Diagnosing pulmonary embolism can be difficult given its highly variable clinical presentation. Our objective was to determine whether a decrease in oxygen saturation or an increase in heart rate while ambulating could be used as an objective tool in the diagnosis of pulmonary embolism. This was a two-site tertiary-care-centre prospective cohort study that enrolled adult emergency department or thrombosis clinic patients with suspected or newly confirmed pulmonary embolism. Patients were asked to participate in a standardized 3-minute walk test, which assessed ambulatory heart rate and ambulatory oxygen saturation. The primary outcome was pulmonary embolism. We enrolled 114 patients, including 30 with pulmonary embolism (26.3%). A ≥2% absolute decrease in ambulatory oxygen saturation and an ambulatory change in heart rate >10 beats per minute (BPM) were significantly associated with pulmonary embolism. An ambulatory heart rate change of >10 BPM had a sensitivity of 96.6% (95% confidence interval [CI] 83.3 to 99.4) and a specificity of 31.0% (95% CI 22.1 to 45.0) for pulmonary embolism. A ≥2% absolute decrease ambulatory oxygen saturation had a sensitivity of 80.2% (95% CI 62.7 to 90.5) and a specificity of 39.3% (95% CI 29.5 to 50.0) for pulmonary embolism. The combination of both variables yielded a sensitivity of 100.0% (95% CI 87.0 to 100.0) and a specificity of 11.0% (95% CI 6.6 to 21.0). In summary, our study found that an ambulatory heart rate change of >10 BPM or a ≥2% absolute decrease in ambulatory oxygen saturation from baseline during a standardized 3-minute walk test are highly correlated with pulmonary embolism. Although the findings appear promising, neither of these variables can currently be recommended as a screening tool for pulmonary embolism until larger prospective studies examine their performance either alone or with pre-existing rules.

Effects of cilnidipine, a novel dihydropyridine calcium antagonist, on autonomic function, ambulatory blood pressure and heart rate in patients with essential hypertension.

PubMed

Minami, J; Kawano, Y; Makino, Y; Matsuoka, H; Takishita, S

2000-12-01

The aim of the present study was to evaluate the effects of cilnidipine, a novel dihydropyridine calcium antagonist, on autonomic function, ambulatory blood pressure and heart rate in patients with essential hypertension. Ten inpatients with mild to moderate essential hypertension (four men and six women; age: 44-64 years) underwent a drug-free period for 7 days and a treatment period with cilnidipine 10 mg orally for another 7 days, in a randomized crossover study. On the sixth day of each period, they underwent autonomic function tests including a mental arithmetic test, a cold pressor test and a Valsalva manoeuvre. After these tests, 24 h ambulatory blood pressure, heart rate, and the electrocardiogram R-R intervals were monitored every 30 min. A power spectral analysis of R-R intervals was performed to obtain the low-and high-frequency components. Cilnidipine significantly decreased the 24 h blood pressure by 6.5 +/- 1.7 mm Hg systolic (mean +/- s.e.mean; P < 0.01) and 5.0 +/- 1.1 mmHg diastolic (P < 0.01), whereas cilnidipine did not change heart rate or any indices of power spectral components. During the cold pressor test, the maximum change in systolic blood pressure and percentage changes in both systolic and diastolic blood pressures were significantly lower during the treatment period with cilnidipine than during the drug-free period. The baroreflex sensitivity measured from the overshoot phase of the Valsalva manoeuvre did not differ significantly between the two periods. Cilnidipine is effective as a once-daily antihypertensive agent and causes little influence on heart rate and the autonomic nervous system in patients with mild to moderate essential hypertension. Moreover, it is suggested that cilnidipine has an additional clinical benefit in the inhibition of the pressor response induced by acute cold stress.

State Anxiety and Nonlinear Dynamics of Heart Rate Variability in Students

PubMed Central

Dimitriev, Aleksey D.

2016-01-01

Objectives Clinical and experimental research studies have demonstrated that the emotional experience of anxiety impairs heart rate variability (HRV) in humans. The present study investigated whether changes in state anxiety (SA) can also modulate nonlinear dynamics of heart rate. Methods A group of 96 students volunteered to participate in the study. For each student, two 5-minute recordings of beat intervals (RR) were performed: one during a rest period and one just before a university examination, which was assumed to be a real-life stressor. Nonlinear analysis of HRV was performed. The Spielberger’s State-Trait Anxiety Inventory was used to assess the level of SA. Results Before adjusting for heart rate, a Wilcoxon matched pairs test showed significant decreases in Poincaré plot measures, entropy, largest Lyapunov exponent (LLE), and pointwise correlation dimension (PD2), and an increase in the short-term fractal-like scaling exponent of detrended fluctuation analysis (α1) during the exam session, compared with the rest period. A Pearson analysis indicated significant negative correlations between the dynamics of SA and Poincaré plot axes ratio (SD1/SD2), and between changes in SA and changes in entropy measures. A strong negative correlation was found between the dynamics of SA and LLE. A significant positive correlation was found between the dynamics of SA and α1. The decreases in Poincaré plot measures (SD1, complex correlation measure), entropy measures, and LLE were still significant after adjusting for heart rate. Corrected α1 was increased during the exam session. As before, the dynamics of adjusted LLE was significantly correlated with the dynamics of SA. Conclusions The qualitative increase in SA during academic examination was related to the decrease in the complexity and size of the Poincaré plot through a reduction of both the interbeat interval and its variation. PMID:26807793

Hormonal contraception among electronic cigarette users and cardiovascular risk: a systematic review.

PubMed

Riley, Halley E M; Berry-Bibee, Erin; England, Lucinda J; Jamieson, Denise J; Marchbanks, Polly A; Curtis, Kathryn M

2016-03-01

Women who use combined hormonal contraceptives and cigarettes have an increased risk for cardiovascular (CV) events. We reviewed the literature to determine whether women who use hormonal contraceptives (HC) and electronic cigarettes (e-cigarettes) also have an increased risk. Systematic review. We searched for articles reporting myocardial infarction (MI), stroke, venous thromboembolism, peripheral arterial disease or changes to CV markers in women using e-cigarettes and HC. We also searched for indirect evidence, such as CV outcomes among e-cigarette users in the general population and among HC users exposed to nicotine, propylene glycol or glycerol. No articles reported on outcomes among e-cigarette users using HC. Among the general population, 13 articles reported on heart rate or blood pressure after e-cigarette use. These markers generally remained normal, even when significant changes were observed. In three studies, changes were less pronounced after e-cigarette use than cigarette use. One MI was reported among 1012 people exposed to e-cigarettes in these studies. One article on nicotine and HC exposure found both exposures to be significantly associated with acute changes to heart rate, though mean heart rate remained normal. No articles on propylene glycol or glycerol and HC exposure were identified. We identified no evidence on CV outcomes among e-cigarette users using HC. Limited data reporting mostly acute outcomes suggested that CV events are rare among e-cigarette users in the general population and that e-cigarettes may affect heart rate and blood pressure less than conventional cigarettes. There is a need for research assessing joint HC and e-cigarette exposure on clinical CV outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Peripheral oxygen saturation, heart rate, and blood pressure during dental treatment of children with cyanotic congenital heart disease

PubMed Central

Dutra, Rosane Menezes Faria; Neves, Itamara Lucia Itagiba; Neves, Ricardo Simões; Atik, Edmar; de Paula Santos, Ubiratan

2014-01-01

OBJECTIVES: In this observational study, we evaluated the peripheral oxygen saturation (SpO2), heart rate, and blood pressure of children with cyanotic congenital heart disease who were undergoing dental extraction. METHODS: Forty-four patients between the ages of 6 and 12 years who underwent upper primary tooth extraction were included in the study. Of these, 20 patients were in the cyanotic congenital heart disease group and 24 were in the control group. RESULTS: Peripheral oxygen saturation, heart rate, and systolic blood pressure in the cyanotic congenital heart disease group varied quite significantly during the treatment protocol (p<0.05), with values of 80.5% (±7.6) to 82.8% (±7.8), 95.3 beats per minute (bpm) (±11.3) to 101.3 bpm (±9.8), and 93.6 mm Hg (±13,3) to 103.8 mm Hg (±12.7), respectively. The variations in the control group during the procedure were also significant. CONCLUSIONS: The changes observed during the study protocol, although statistically significant, were mild and lacked clinical relevance. The results indicate that dental treatment of children with cyanotic heart disease using a standardized protocol in decentralized offices without the support of a surgical center is safe. PMID:24838895

Effects of active recovery on autonomic and haemodynamic responses after aerobic exercise.

PubMed

Soares, Antonio H G; Oliveira, Tiago P; Cavalcante, Bruno R; Farah, Breno Q; Lima, Aluísio H R A; Cucato, Gabriel G; Cardoso, Crivaldo G; Ritti-Dias, Raphael M

2017-01-01

The aim of this study was to examine the effect of active recovery on autonomic and haemodynamic responses after exercise in healthy adults. Nineteen healthy young male individuals underwent two experimental sessions: exercise with active recovery (AR) and exercise with passive recovery (PR). The exercise sessions comprised three phases: warm-up (5 min), exercise phase (cycle ergometer, 30 min, intensity between 60 and 70% of the heart rate reserve) and recovery (5 min). In the AR, the subjects remained cycling in the recovery phase at intensity between 30% and 35% of heart rate reserve, while in the PR, the subjects stopped the exercise after finishing the exercise phase. Blood pressure and heart rate were measured before and over the 30 min after the interventions. There were no differences for systolic and diastolic blood pressures, heart rate and rate pressure product between active and passive recovery sessions. Also, all heart rate variability parameters changed similarly after exercise with passive or active recovery sessions. In summary, exercise with active recovery does not affect the autonomic and haemodynamic responses after moderate-intensity aerobic exercise in healthy young male individuals. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Design of a Wireless Sensor System with the Algorithms of Heart Rate and Agility Index for Athlete Evaluation

PubMed Central

Li, Meina; Kim, Youn Tae

2017-01-01

Athlete evaluation systems can effectively monitor daily training and boost performance to reduce injuries. Conventional heart-rate measurement systems can be easily affected by artifact movement, especially in the case of athletes. Significant noise can be generated owing to high-intensity activities. To improve the comfort for athletes and the accuracy of monitoring, we have proposed to combine robust heart rate and agility index monitoring algorithms into a small, light, and single node. A band-pass-filter-based R-wave detection algorithm was developed. The agility index was calculated by preprocessing with band-pass filtering and employing the zero-crossing detection method. The evaluation was conducted under both laboratory and field environments to verify the accuracy and reliability of the algorithm. The heart rate and agility index measurements can be wirelessly transmitted to a personal computer in real time by the ZigBee telecommunication system. The results show that the error rate of measurement of the heart rate is within 2%, which is comparable with that of the traditional wired measurement method. The sensitivity of the agility index, which could be distinguished as the activity speed, changed slightly. Thus, we confirmed that the developed algorithm could be used in an effective and safe exercise-evaluation system for athletes. PMID:29039763

Mathematical modelling of the maternal cardiovascular system in the three stages of pregnancy.

PubMed

Corsini, Chiara; Cervi, Elena; Migliavacca, Francesco; Schievano, Silvia; Hsia, Tain-Yen; Pennati, Giancarlo

2017-09-01

In this study, a mathematical model of the female circulation during pregnancy is presented in order to investigate the hemodynamic response to the cardiovascular changes associated with each trimester of pregnancy. First, a preliminary lumped parameter model of the circulation of a non-pregnant female was developed, including the heart, the systemic circulation with a specific block for the uterine district and the pulmonary circulation. The model was first tested at rest; then heart rate and vascular resistances were individually varied to verify the correct response to parameter alterations characterising pregnancy. In order to simulate hemodynamics during pregnancy at each trimester, the main changes applied to the model consisted in reducing vascular resistances, and simultaneously increasing heart rate and ventricular wall volumes. Overall, reasonable agreement was found between model outputs and in vivo data, with the trends of the cardiac hemodynamic quantities suggesting correct response of the heart model throughout pregnancy. Results were reported for uterine hemodynamics, with flow tracings resembling typical Doppler velocity waveforms at each stage, including pulsatility indexes. Such a model may be used to explore the changes that happen during pregnancy in female with cardiovascular diseases. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Non-linear scaling of oxygen consumption and heart rate in a very large cockroach species (Gromphadorhina portentosa): correlated changes with body size and temperature.

PubMed

Streicher, Jeffrey W; Cox, Christian L; Birchard, Geoffrey F

2012-04-01

Although well documented in vertebrates, correlated changes between metabolic rate and cardiovascular function of insects have rarely been described. Using the very large cockroach species Gromphadorhina portentosa, we examined oxygen consumption and heart rate across a range of body sizes and temperatures. Metabolic rate scaled positively and heart rate negatively with body size, but neither scaled linearly. The response of these two variables to temperature was similar. This correlated response to endogenous (body mass) and exogenous (temperature) variables is likely explained by a mutual dependence on similar metabolic substrate use and/or coupled regulatory pathways. The intraspecific scaling for oxygen consumption rate showed an apparent plateauing at body masses greater than about 3 g. An examination of cuticle mass across all instars revealed isometric scaling with no evidence of an ontogenetic shift towards proportionally larger cuticles. Published oxygen consumption rates of other Blattodea species were also examined and, as in our intraspecific examination of G. portentosa, the scaling relationship was found to be non-linear with a decreasing slope at larger body masses. The decreasing slope at very large body masses in both intraspecific and interspecific comparisons may have important implications for future investigations of the relationship between oxygen transport and maximum body size in insects.

The effect of 60-h sleep deprivation on cardiovascular regulation and body temperature.

PubMed

Vaara, Jani; Kyröläinen, Heikki; Koivu, Mikko; Tulppo, Mikko; Finni, Taija

2009-02-01

This study examined cardiovascular regulation and body temperature (BT) during 60 h of sleep deprivation in 20 young healthy cadets. Heart rate variability was measured during an active orthostatic test (AOT). Measurements were performed each day in the morning and evening after 2, 14, 26, 38, 50 and 60 h of sleep deprivation. In AOT, in the sitting and standing positions, heart rate decreased (P < 0.001), while high frequency and low frequency power increased (P < 0.05-0.001) during sleep deprivation. Body temperature also decreased (P < 0.001), but no changes were detected in blood pressure. In conclusion, the accumulation of 60 h of sleep loss resulted in increased vagal outflow, as evidenced by decreased heart rate. In addition, BT decreased during sleep deprivation. Thus, sleep deprivation causes alterations in autonomic regulation of the heart, and in thermoregulation.

Validation of the Nonin 8600V Pulse Oximeter for heart rate and oxygen saturation measurements in rats.

PubMed

Bernard, Susan L; An, Dowon; Glenny, Robb W

2004-05-01

This report validates the use and limitations of the Nonin Pulse Oximeter for measuring heart rate and oxygen saturation in rats. Eight anesthetized Sprague-Dawley rats were intubated and catheterized. Oxygen saturation was directly measured from arterial blood by using a Radiometer OSM3 Hemoximeter adjusted for rat blood as well as indirectly by using the Nonin Pulse Oximeter. Oxygen saturation was changed by varying the level of inhaled oxygen. Heart rate was measured in two ways: 1) by using the signal from the Nonin Pulse Oximeter and 2) by counting the pressure pulses from the transduced blood pressure. There was excellent agreement between heart rate values measured by the Nonin Pulse Oximeter and that measured by counting the pulses from the arterial blood pressure recording. The Nonin Pulse Oximeter underestimated oxygen saturations by about 3% to 5% compared to the Hemoximeter. Overall, the pulse oximeter reflected important trends in oxygen saturations, making it a useful tool for laboratory animal medicine.

Cardiorespiratory responses to orthostasis and the effects of propranolol

NASA Technical Reports Server (NTRS)

Loeppky, J. A.

1975-01-01

Cardiac output and gas exchange were determined serially using the single-breath method of Kim et al. before, during, and after orthostasis on six subjects after beta-adrenergic blockage and in duplicate controls. In the latter, heart rate increased and pulse pressure dropped immediately on tilting to 60 deg and remained stable while cardiac output and stroke volume declined gradually over 21 min upright. On propranolol, heart rate was 10 bpm lower supine and 20 bpm less at 60 deg but cardiac output was only slightly lower before and following tilt-up. However, after 15 min upright, stroke volume and cardiac output recovered on propranolol exceeding the controls after 21 min without change in heart rate. Returning to supine, heart rate dropped in all tests with a transitory increase in stroke volume, cardiac output and arteriovenous O2 difference. At the same time, apparent O2 uptake increased temporarily, reflecting the return of pooled venous blood to the lungs. Orthostatic tolerance did not appear to be affected by beta-adrenergic blockade.

Estimating the cost of mental loading in a bimodal divided-attention task: Combining reaction time, heart-rate variability and signal-detection theory

NASA Technical Reports Server (NTRS)

Casper, Patricia A.; Kantowitz, Barry H.

1988-01-01

Multiple approaches are necessary for understanding and measuring workload. In particular, physiological systems identifiable by employing cardiac measures are related to cognitive systems. One issue of debate in measuring cardiac output is the grain of analysis used in recording and summarizing data. Various experiments are reviewed, the majority of which were directed at supporting or contradicting Lacey's intake-rejection hypothesis. Two of the experiments observed heart rate in operational environments and found virtually no changes associated with mental load. The major problems facing researchers using heart rate variability, or sinus arrhthmia, as a dependent measure have been associated with valid and sensitive scoring and preventing contamination of observed results by influences unrelated to cognition. Spectral analysis of heart rate variability offers two useful procedures: analysis from the time domain and analysis from the frequency domain. Most recently, data have been collected in a divided attention experiment, the performance measures and cardiac measures of which are detailed.

Trends in Modifiable Risk Factors Are Associated With Declining Incidence of Hospitalized and Nonhospitalized Acute Coronary Heart Disease in a Population.

PubMed

Mannsverk, Jan; Wilsgaard, Tom; Mathiesen, Ellisiv B; Løchen, Maja-Lisa; Rasmussen, Knut; Thelle, Dag S; Njølstad, Inger; Hopstock, Laila Arnesdatter; Bønaa, Kaare Harald

2016-01-05

Few studies have used individual person data to study whether contemporary trends in the incidence of coronary heart disease are associated with changes in modifiable coronary risk factors. We identified 29 582 healthy men and women ≥25 years of age who participated in 3 population surveys conducted between 1994 and 2008 in Tromsø, Norway. Age- and sex-adjusted incidence rates were calculated for coronary heart disease overall, out-of-hospital sudden death, and hospitalized ST-segment-elevation and non-ST-segment-elevation myocardial infarction. We measured coronary risk factors at each survey and estimated the relationship between changes in risk factors and changes in incidence trends. A total of 1845 participants had an incident acute coronary heart disease event during 375 064 person-years of follow-up from 1994 to 2010. The age- and sex-adjusted incidence of total coronary heart disease decreased by 3% (95% confidence interval, 2.0-4.0; P<0.001) each year. This decline was driven by decreases in out-of-hospital sudden death and hospitalized ST-segment-elevation myocardial infarction. Changes in coronary risk factors accounted for 66% (95% confidence interval, 48-97; P<0.001) of the decline in total coronary heart disease. Favorable changes in cholesterol contributed 32% to the decline, whereas blood pressure, smoking, and physical activity each contributed 14%, 13%, and 9%, respectively. We observed a substantial decline in the incidence of coronary heart disease that was driven by reductions in out-of-hospital sudden death and hospitalized ST-segment-elevation myocardial infarction. Changes in modifiable coronary risk factors accounted for 66% of the decline in coronary heart disease events. © 2015 American Heart Association, Inc.

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”.

Increased Exposure to Rigid Routines can Lead to Increased Challenging Behavior Following Changes to Those Routines.

PubMed

Bull, Leah E; Oliver, Chris; Callaghan, Eleanor; Woodcock, Kate A

2015-06-01

Several neurodevelopmental disorders are associated with preference for routine and challenging behavior following changes to routines. We examine individuals with Prader-Willi syndrome, who show elevated levels of this behavior, to better understand how previous experience of a routine can affect challenging behavior elicited by disruption to that routine. Play based challenges exposed 16 participants to routines, which were either adhered to or changed. Temper outburst behaviors, heart rate and movement were measured. As participants were exposed to routines for longer before a change (between 10 and 80 min; within participants), more temper outburst behaviors were elicited by changes. Increased emotional arousal was also elicited, which was indexed by heart rate increases not driven by movement. Further study will be important to understand whether current intervention approaches that limit exposure to changes, may benefit from the structured integration of flexibility to ensure that the opportunity for routine establishment is also limited.

Clinical safety of 3-T brain magnetic resonance imaging in newborns.

PubMed

Fumagalli, Monica; Cinnante, Claudia Maria; Calloni, Sonia Francesca; Sorrentino, Gabriele; Gorla, Ilaria; Plevani, Laura; Pesenti, Nicola; Sirgiovanni, Ida; Mosca, Fabio; Triulzi, Fabio

2018-03-29

The effects and potential hazards of brain magnetic resonance imaging (MRI) at 3 T in newborns are debated. Assess the impact of 3-T MRI in newborns on body temperature and physiological parameters. Forty-nine newborns, born preterm and at term, underwent 3-T brain MRI at term-corrected age. Rectal and skin temperature, oxygen saturation and heart rate were recorded before, during and after the scan. A statistically significant increase in skin temperature of 0.6 °C was observed at the end of the MRI scan (P<0.01). There was no significant changes in rectal temperature, heart rate or oxygen saturation. Core temperature, heart rate and oxygen saturation in newborns were not affected by 3-T brain MR scanning.

Effects of music on cardiovascular responses in men with essential hypertension compared with healthy men based on introversion and extraversion.

PubMed

Namdar, Hossein; Taban Sadeghi, Mohammadreza; Sabourimoghaddam, Hassan; Sadeghi, Babak; Ezzati, Davoud

2014-01-01

The present research investigated the effects of two different types of music on cardiovascular responses in essential hypertensive men in comparison with healthy men based on introversion and extraversion. One hundred and thirteen hypertensive men referred to Madani Heart Hospital in Tabriz completed the NEO-FFI Questionnaire and after obtaining acceptable scores were classified in four groups: introvert patients, extravert patients, introvert healthy subjects, and extravert healthy subjects (each group with 25 samples with age range 31-50). Baseline blood pressure and heart rate of each subject was recorded without any stimulus. Then subjects were exposed to slow-beat music and blood pressure and heart rate were recorded. After15 minute break, and a little cognitive task for distraction, subjects were exposed to fast-beat music and blood pressure and heart rate were recorded again. Multivariate analysis of covariance (MANCOVA) test showed that extravert patient subjects obtained greater reduction in systolic blood pressure and heart rate after presenting slow-beat music compared with introvert patients (P= 0.035, and P= 0.033 respectively). And extravert healthy subjects obtained greater reduction in heart rate after presenting slow-beat music compared with introvert healthy subjects (P= 0.036). However, there are no significant differences between introvert and extravert groups in systolic and diastolic blood pressure and heart rate after presenting fast-beat music. Based on our results, introvert subjects experience negative emotions more than extravert subjects and negative emotions cause less change in blood pressure in these subjects compared with extravert subjects.

Effects of Music on Cardiovascular Responses in Men with Essential Hypertension Compared with Healthy Men Based on Introversion and Extraversion

PubMed Central

Namdar, Hossein; Taban Sadeghi, Mohammadreza; Sabourimoghaddam, Hassan; Sadeghi, Babak; Ezzati, Davoud

2014-01-01

Introduction: The present research investigated the effects of two different types of music on cardiovascular responses in essential hypertensive men in comparison with healthy men based on introversion and extraversion. Methods: One hundred and thirteen hypertensive men referred to Madani Heart Hospital in Tabriz completed the NEO-FFI Questionnaire and after obtaining acceptable scores were classified in four groups: introvert patients, extravert patients, introvert healthy subjects, and extravert healthy subjects (each group with 25 samples with age range 31-50). Baseline blood pressure and heart rate of each subject was recorded without any stimulus. Then subjects were exposed to slow-beat music and blood pressure and heart rate were recorded. After15 minute break, and a little cognitive task for distraction, subjects were exposed to fast-beat music and blood pressure and heart rate were recorded again. Results: Multivariate analysis of covariance (MANCOVA) test showed that extravert patient subjects obtained greater reduction in systolic blood pressure and heart rate after presenting slow-beat music compared with introvert patients (P= 0.035, and P= 0.033 respectively). And extravert healthy subjects obtained greater reduction in heart rate after presenting slow-beat music compared with introvert healthy subjects (P= 0.036). However, there are no significant differences between introvert and extravert groups in systolic and diastolic blood pressure and heart rate after presenting fast-beat music. Conclusion: Based on our results, introvert subjects experience negative emotions more than extravert subjects and negative emotions cause less change in blood pressure in these subjects compared with extravert subjects. PMID:25320667

The role of the autonomic nervous system in the resting tachycardia of human hyperthyroidism.

PubMed

Maciel, B C; Gallo, L; Marin Neto, J A; Maciel, L M; Alves, M L; Paccola, G M; Iazigi, N

1987-02-01

The mechanisms that control resting heart rate in hyperthyroidism were evaluated in six patients before and after treatment with propylthiouracil. The patients were subjected to pharmacological blockade under resting conditions in two experimental sessions: first session, propranolol (0.2 mg/kg body weight); second session, atropine (0.04 mg/kg body weight) followed by propranolol (0.2 mg/kg body weight). All drugs were administered intravenously. Resting heart rate was significantly reduced from 100 +/- 6.5 beats/min to 72 +/- 2.5 beats/min (P less than 0.005) after clinical and laboratory control of the disease. After double blockade, intrinsic heart rate was reduced from 105 +/- 6.8 beats/min before treatment to 98 +/- 6.0 beats/min after treatment (P less than 0.025). The reduction in heart rate caused by propranolol was not significantly different before (-13 +/- 1.4 beats/min) and after (-9 +/- 1.0 beats/min) propylthiouracil. In contrast, atropine induced a higher elevation of heart rate after treatment (45 +/- 8.6 beats/min) than before treatment (26 +/- 4.0 beats/min). The present results suggest no appreciable participation of the sympathetic component of the autonomic nervous system in the tachycardia of hyperthyroidism, at least under the conditions of the present study. The small change observed in intrinsic heart rate, although significant, seems to indicate that this is not the most important mechanism involved in this tachycardia. Our results suggest that an important reduction in the efferent activity of the parasympathetic component participates in the mechanisms that modify resting heart rte in hyperthyroidism.

Female Listeners’ Autonomic Responses to Dramatic Shifts Between Loud and Soft Music/Sound Passages: A Study of Heavy Metal Songs

PubMed Central

Cheng, Tzu-Han; Tsai, Chen-Gia

2016-01-01

Although music and the emotion it conveys unfold over time, little is known about how listeners respond to shifts in musical emotions. A special technique in heavy metal music utilizes dramatic shifts between loud and soft passages. Loud passages are penetrated by distorted sounds conveying aggression, whereas soft passages are often characterized by a clean, calm singing voice and light accompaniment. The present study used heavy metal songs and soft sea sounds to examine how female listeners’ respiration rates and heart rates responded to the arousal changes associated with auditory stimuli. The high-frequency power of heart rate variability (HF-HRV) was used to assess cardiac parasympathetic activity. The results showed that the soft passages of heavy metal songs and soft sea sounds expressed lower arousal and induced significantly higher HF-HRVs than the loud passages of heavy metal songs. Listeners’ respiration rate was determined by the arousal level of the present music passage, whereas the heart rate was dependent on both the present and preceding passages. Compared with soft sea sounds, the loud music passage led to greater deceleration of the heart rate at the beginning of the following soft music passage. The sea sounds delayed the heart rate acceleration evoked by the following loud music passage. The data provide evidence that sound-induced parasympathetic activity affects listeners’ heart rate in response to the following music passage. These findings have potential implications for future research on the temporal dynamics of musical emotions. PMID:26925009

The buffering power of overt socially supportive and unsupportive behaviors from the significant other on posttraumatic stress disorder individuals' emotional state.

PubMed

Guay, Stéphane; Nachar, Nadim; Lavoie, Marc E; Marchand, André; O'Connor, Kieron P

2017-01-01

Social support is one of the three strongest predictors of posttraumatic stress disorder (PTSD). In the present study, we aimed to assess the buffering power of overt socially supportive and unsupportive behaviors from the significant other, in a group with PTSD and a comparison group. A total of 46 individuals with PTSD and 42 individuals with obsessive-compulsive disorder (OCD) or panic disorder (PD) completed diagnostic interviews and an anxiety-oriented social interaction with a significant other. Heart rate of participants was continuously measured during this interaction and overt social behaviors from the significant other were recorded on videotape and coded using a validated system. Changes in heart rate in PTSD participants correlated negatively with changes in overt socially supportive behaviors from their significant other (r from -.36 to -.50, p < .05), while changes in overt unsupportive social behaviors from their significant other did not yield any significant correlation (r from -.01 to .05, p > .05). No such statistically significant association emerged in the group with OCD or PD (r from .01 to -.27, p > .05). This study sustain the buffering power of overt supportive behaviors from the significant other on heart rate changes in PTSD.

Long-Term Study of Heart Rate Variability Responses to Changes in the Solar and Geomagnetic Environment.

PubMed

Alabdulgader, Abdullah; McCraty, Rollin; Atkinson, Michael; Dobyns, York; Vainoras, Alfonsas; Ragulskis, Minvydas; Stolc, Viktor

2018-02-08

This long-term study examined relationships between solar and magnetic factors and the time course and lags of autonomic nervous system (ANS) responses to changes in solar and geomagnetic activity. Heart rate variability (HRV) was recorded for 72 consecutive hours each week over a five-month period in 16 participants in order to examine ANS responses during normal background environmental periods. HRV measures were correlated with solar and geomagnetic variables using multivariate linear regression analysis with Bonferroni corrections for multiple comparisons after removing circadian influences from both datasets. Overall, the study confirms that daily ANS activity responds to changes in geomagnetic and solar activity during periods of normal undisturbed activity and it is initiated at different times after the changes in the various environmental factors and persist over varying time periods. Increase in solar wind intensity was correlated with increases in heart rate, which we interpret as a biological stress response. Increase in cosmic rays, solar radio flux, and Schumann resonance power was all associated with increased HRV and parasympathetic activity. The findings support the hypothesis that energetic environmental phenomena affect psychophysical processes that can affect people in different ways depending on their sensitivity, health status and capacity for self-regulation.

Changes of heart rate variability and prefrontal oxygenation during Tai Chi practice versus arm ergometer cycling.

PubMed

Lu, Xi; Hui-Chan, Christina Wan-Ying; Tsang, William Wai-Nam

2016-11-01

[Purpose] Exercise has been shown to improve cardiovascular fitness and cognitive function. Whether the inclusion of mind over exercise would increase parasympathetic control of the heart and brain activities more than general exercise at a similar intensity is not known. The aim of this study was to compare the effects of Tai Chi (mind-body exercise) versus arm ergometer cycling (body-focused exercise) on the heart rate variability and prefrontal oxygenation level. [Subjects and Methods] A Tai Chi master was invited to perform Tai Chi and arm ergometer cycling with similar exercise intensity on two separate days. Heart rate variability and prefrontal oxyhemoglobin levels were measured continuously by a RR recorder and near-infrared spectroscopy, respectively. [Results] During Tai Chi exercise, spectral analysis of heart rate variability demonstrated a higher high-frequency power as well as a lower low-frequency/high-frequency ratio than during ergometer cycling, suggesting increased parasympathetic and decreased sympathetic control of the heart. Also, prefrontal oxyhemoglobin and total hemoglobin levels were higher than those during arm ergometer exercise. [Conclusion] These findings suggest that increased parasympathetic control of the heart and prefrontal activities may be associated with Tai Chi practice. Having a "mind" component in Tai Chi could be more beneficial for older adults' cardiac health and cognitive function than body-focused ergometer cycling.

How are tonic and phasic cardiovascular changes related to central motor command?

PubMed

Jennings, J R; van der Molen, M W; Brock, K; Somsen, R J

1993-07-01

We examined the influence of central motor command on heart rate, respiration, and peripheral vascular activity. Central command was enhanced or reduced using tendon vibration. Muscle tension was held constant permitting the examination of variation in central command. Experiment 1 demonstrated in 13 college-aged males an enhancement of heart rate and vascular responses to an isometric, extensor contraction when vibration of the flexor tendon was added. Experiment 2 asked whether changes in central command interacted with phasic cardiovascular changes such as stimulus-linked anticipatory cardiac deceleration. Twenty college-aged males performed either an isometric flexor or extensor contraction with or without flexor tendon vibration. As expected, vibration enhanced cardiovascular change with extensor contraction more than with flexor contraction. Relative to control contractions, however, the flexor change was not an absolute decrease in cardiovascular change. More importantly, tendon vibration failed to alter phasic cardiovascular changes. Force and central commands for force induce cardiovascular change, but this change seems independent of phasic changes induced by the anticipation and processing of environmental stimuli.

Higher Precision of Heart Rate Compared with VO2 to Predict Exercise Intensity in Endurance-Trained Runners.

PubMed

Reis, Victor M; den Tillaar, Roland Van; Marques, Mario C

2011-01-01

The aim of the present study was to assess the precision of oxygen uptake with heart rate regression during track running in highly-trained runners. Twelve national and international level male long-distance road runners (age 30.7 ± 5.5 yrs, height 1.71 ± 0.04 m and mass 61.2 ± 5.8 kg) with a personal best on the half marathon of 62 min 37 s ± 1 min 22 s participated in the study. Each participant performed, in an all-weather synthetic track five, six min bouts at constant velocity with each bout at an increased running velocity. The starting velocity was 3.33 m·s(-1) with a 0.56 m·s(-1) increase on each subsequent bout. VO2 and heart rate were measured during the runs and blood lactate was assessed immediately after each run. Mean peak VO2 and mean peak heart rate were, respectively, 76.2 ± 9.7 mL·kg(-1)·min(-1) and 181 ± 13 beats·min(-1). The linearity of the regressions between heart rate, running velocity and VO2 were all very high (r > 0.99) with small standard errors of regression (i.e. Sy.x < 5% at the velocity associated with the 2 and 4 mmol·L(-1) lactate thresholds). The strong relationships between heart rate, running velocity and VO2 found in this study show that, in highly trained runners, it is possible to have heart rate as an accurate indicator of energy demand and of the running speed. Therefore, in this subject cohort it may be unnecessary to use VO2 to track changes in the subjects' running economy during training periods. Key pointsHeart rate is used in the control of exercise intensity in endurance sports.However, few studies have quantified the precision of its relationship with oxygen uptake in highly trained runners.We evaluated twelve elite half-marathon runners during track running at various intensities and established three regressions: oxygen uptake / heart rate; heart rate / running velocity and oxygen uptake / running velocity.The three regressions presented, respectively, imprecision of 4,2%, 2,75% and 4,5% at the velocity associated with the 4 mmol·L(-1) threshold.The results of the present study show that, in highly trained runners, it is possible to use heart rate as an accurate index of the external work rate during sub maximal running speeds.

Aging and CaMKII alter intracellular Ca2+ transients and heart rhythm in Drosophila melanogaster.

PubMed

Santalla, Manuela; Valverde, Carlos A; Harnichar, Ezequiel; Lacunza, Ezequiel; Aguilar-Fuentes, Javier; Mattiazzi, Alicia; Ferrero, Paola

2014-01-01

Aging is associated to disrupted contractility and rhythmicity, among other cardiovascular alterations. Drosophila melanogaster shows a pattern of aging similar to human beings and recapitulates the arrhythmogenic conditions found in the human heart. Moreover, the kinase CaMKII has been characterized as an important regulator of heart function and an arrhythmogenic molecule that participate in Ca2+ handling. Using a genetically engineered expressed Ca2+ indicator, we report changes in cardiac Ca2+ handling at two different ages. Aging prolonged relaxation, reduced spontaneous heart rate (HR) and increased the occurrence of arrhythmias, ectopic beats and asystoles. Alignment between Drosophila melanogaster and human CaMKII showed a high degree of conservation and indicates that relevant phosphorylation sites in humans are also present in the fruit fly. Inhibition of CaMKII by KN-93 (CaMKII-specific inhibitor), reduced HR without significant changes in other parameters. By contrast, overexpression of CaMKII increased HR and reduced arrhythmias. Moreover, it increased fluorescence amplitude, maximal rate of rise of fluorescence and reduced time to peak fluorescence. These results suggest that CaMKII in Drosophila melanogaster acts directly on heart function and that increasing CaMKII expression levels could be beneficial to improve contractility.

Utility of Time and Frequency Domain Parameters of Heart Rate Variability in the Context of Autonomic Disorders Characterized by Orthostatic Dysfunction.

PubMed

Baker, Jacquie; Racosta, Juan M; Balint, Brittany; Kimpinski, Kurt

2018-03-01

The clinical significance of heart rate variability in the context of autonomic dysfunction continues to be a matter of debate. A consensus is lacking on the best heart rate variability measures for clinical purposes. Therefore, the purpose of this study was to investigate the utility of heart rate variability parameters in healthy versus autonomic dysfunction. Healthy young (n = 134), healthy older (n = 32), and patients with mild (postural tachycardia syndrome; n = 25) and severe (neurogenic orthostatic hypotension; n = 34) autonomic dysfunction were included. Time and frequency parameters during baseline, head-up tilt (HUT), and heart rate response to deep breathing (HRDB) were compared. Cardiovagal time parameters were significantly reduced during HUT in healthy young and postural tachycardia syndrome (P < 0.001). Healthy young had significantly higher time parameters during baseline, HUT, and HRDB (P < 0.01). This was reflected by a significantly lower resting heart rate (HR) (61.4 ± 9.0 bpm vs. 76.8 ± 13.6 bpm; P < 0.001) and a smaller [INCREMENT]HR during HUT (32.8 ± 10.5 bpm vs. 44.4 ± 13.3 bpm; P < 0.001). Time parameters increased in young and postural tachycardia syndrome during HRDB, which was characterized by a nonsignificant difference in [INCREMENT]HR between both groups. Time parameters were significantly higher in healthy old versus neurogenic orthostatic hypotension at rest and during HRDB (P < 0.05). During HUT, only the SD of all normal RR intervals remained significantly higher. Heart rate changes corroborated these findings. Resting HR was significantly lower in healthy older (62.6 ± 11.0 bpm vs. 70.7 ± 12.4 bpm), and [INCREMENT]HR during HRDB was significantly higher (15.9 ± 9.2 bpm vs. 3.9 ± 4.2 bpm; P < 0.001). During HUT, [INCREMENT]HR showed no significant differences. Time domain parameters of heart rate variability have a greater utility than frequency parameters in clinical autonomic disorders.

Autonomic Evaluation of Patients With Gastroparesis and Neurostimulation: Comparisons of Direct/Systemic and Indirect/Cardiac Measures

PubMed Central

Stocker, Abigail; Abell, Thomas L.; Rashed, Hani; Kedar, Archana; Boatright, Ben; Chen, Jiande

2016-01-01

Background Disorders of nausea, vomiting, abdominal pain, and related problems often are manifestations of gastrointestinal, neuromuscular, and/or autonomic dysfunction. Many of these patients respond to neurostimulation, either gastric electrical stimulation or electroacupuncture. Both of these therapeutic techniques appear to influence the autonomic nervous system which can be evaluated directly by traditional testing and indirectly by heart rate variability. Methods We studied patients undergoing gastric neuromodulation by both systemic autonomic testing (39 patients, six males and 33 females, mean age 38 years) and systemic autonomic testing and heart rate variability (35 patients, seven males and 28 females, mean age 37 years) testing before and after gastric neuromodulation. We also performed a pilot study using both systemic autonomic testing and heart rate variability in a small number of patients (five patients, all females, mean age 48.6 years) with diabetic gastroparesis at baseline to compare the two techniques at baseline. Systemic autonomic testing and heart rate variability were performed with standardized techniques and gastric electrical stimulation was performed as previously described with electrodes implanted serosally in the myenteric plexus. Results Both systemic autonomic testing and heart rate variability measures were often abnormal at baseline and showed changes after gastric neuromodulation therapy in two groups of symptomatic patients. Pilot data on a small group of similar patients with systemic automatic nervous measures and heart rate variability showed good concordance between the two techniques. Conclusions Both traditional direct autonomic measures and indirect measures such as heart rate variability were evaluated, including a pilot study of both methods in the same patient group. Both appear to be useful in evaluation of patients at baseline and after stimulation therapies; however, a future full head-to-head comparison is warranted. PMID:27785318

[Study on effect of aqueous extracts from aconite on "dose-time-toxicity" relationships in mice hearts].

PubMed

Feng, Qun; Li, Xiao-yu; Luan, Yong-fu; Sun, Sai-nan; Sun, Rong

2015-03-01

To study the effect of single administration of aqueous extracts from aconite on "dose-toxicity" relationship and "time-toxicity" relationship of mice hearts, through changes in electrocardiogram (ECG) and serum biochemical indexes. Mice were grouped according to different drug doses and time points, and orally administered with water extracts from aconite for once to observe the changes of mice ECG before and after the administration, calculate visceral indexes heart, liver and kidney, and detect levels of CK, LDH, BNP and CTn-I in serum. According to the "time-toxicity" relationship study, at 5 min after oral administration with aqueous extracts from aconite in mice, the heart rate of mice began rising, reached peak at 60 min and then slowly reduced; QRS, R amplitude, T duration and amplitude and QT interval declined at 5 min, reduced to the bottom at 60 min and then gradually elevated. The levels of CK, LDH, BNP and CTn-I in serum elevated at 5 min and reached the peak at 60 min, with no significant change in ratios of organs to body at different time points. On the basis of the "dose-toxicity" relationship, with the increase in single dose of aqueous extracts from aconite, the heart rate of mice. QRS, T duration and amplitude and QT interval declined gradually, and levels of CK, LDH, BNP and CTn-I in serum slowly elevated, with a certain dose dependence and no significant change in ratios of organs to body in mice. Single oral administration of different doses of aqueous extracts from aconite could cause different degrees of heart injury at different time points, with a certain dose dependence. Its peak time of toxicity is at 60 min after the administration of aqueous extracts from aconite.

Rapid resetting of rabbit aortic baroreceptors and reflex heart rate responses by directional changes in blood pressure.

PubMed

Burke, S L; Dorward, P K; Korner, P I

1986-09-01

In both anaesthetized and conscious rabbits, perivascular balloon inflations slowly raised or lowered mean arterial pressure (M.A.P.), at 1-2 mmHg/s, from resting to various plateau pressures. Deflations then returned the M.A.P. to resting. 'Steady-state' curves relating M.A.P. to unitary aortic baroreceptor firing, integrated aortic nerve activity and heart rate were derived during the primary and return pressure changes and they formed typical hysteresis loops. In single units, return M.A.P.-frequency curves were shifted in the same direction as the primary pressure changes by an average 0.37 mmHg per mmHg change in M.A.P. Shifts were linearly related to the changes in M.A.P. between resting and plateau levels for all pressure rises and for falls less than 30 mmHg. They were established within 30 s and were quantitatively similar to the rapid resetting of baroreceptor function curves found 15 min-2 h after a change in resting M.A.P. (Dorward, Andresen, Burke, Oliver & Korner, 1982). Unit threshold pressures were shifted within 20 s to the same extent as the over-all curve shift to which they contributed. In the whole aortic nerve, return M.A.P.-integrated activity curves were shifted to same degree as unit function curves in both anaesthetized and conscious rabbits. Simultaneous shifts of return reflex M.A.P.-heart rate curves were also seen in conscious rabbits within 30 s. During M.A.P. falls, receptor and reflex hysteresis was similar, but during M.A.P. rises, reflex shifts were double baroreceptor shifts, suggesting the involvement of other pressure-sensitive receptors. We conclude that hysteresis shifts in baroreceptor function curves, which follow the reversal of slow ramp changes in blood pressure are a form of rapid resetting. They are accompanied by rapid resetting of reflex heart rate responses. We regard this as an important mechanism in blood pressure control which produces relatively high-gain reflex responses, during slow directional pressure changes, over a wider range of absolute pressure levels than would otherwise be possible.

Evaluation and management of bradycardia in neonates and children.

PubMed

Baruteau, Alban-Elouen; Perry, James C; Sanatani, Shubhayan; Horie, Minoru; Dubin, Anne M

2016-02-01

Heart rate is commonly used in pediatric early warning scores. Age-related changes in the anatomy and physiology of infants and children produce normal ranges for electrocardiogram features that differ from adults and vary with age. Bradycardia is defined as a heart rate below the lowest normal value for age. Pediatric bradycardia most commonly manifests as sinus bradycardia, junctional bradycardia, or atrioventricular block. As a result of several different etiologies, it may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited sinus node dysfunction or progressive cardiac conduction disorders. Management and eventual prognosis of bradycardia in the young are entirely dependent upon the underlying cause. Reasons to intervene for bradycardia are the association of related symptoms and/or the downstream risk of heart failure or pause-dependent tachyarrhythmia. The simplest aspect of severe bradycardia management is reflected in the Pediatric and Advanced Life Support (PALS) guidelines. Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current practice for evaluation and management of bradycardia in neonates and children. Bradycardia is defined as a heart rate below the lowest normal value for age. Age related changes in the anatomy and physiology of infants and children produce normal ranges for electrocardiogram features that differ from adults and vary with age. Pediatric bradycardia most commonly manifests as sinus bradycardia, junctional bradycardia, or atrioventricular block. Management and eventual prognosis of bradycardia in the young are entirely dependent upon the underlying cause. Bradycardia may occur in a structurally normal heart or in association with congenital heart disease. Genetic variants in multiple genes have been described. Reasons to intervene for bradycardia are the association of related symptoms and/or the downstream risk of heart failure or pause-dependent tachyarrhythmia. Early diagnosis and appropriate management are critical in order to prevent sudden death.

Frequency and duration of interval training programs and changes in aerobic power

NASA Technical Reports Server (NTRS)

Fox, E. L.; Bartels, R. L.; Obrien, R.; Bason, R.; Mathews, D. K.; Billings, C. E.

1975-01-01

The present study was designed to ascertain whether a training frequency of 2 days/wk for a 7- and 13-wk interval training program would produce improvement in maximal aerobic power comparable to that obtained from 7- and 13-wk programs of the same intensity consisting of 4 training days/wk. After training, there was a significant increase in maximal aerobic power that was independent of both training frequency and duration. Maximal heart rate was significantly decreased following training. Submaximal aerobic power did not change with training, but submaximal heart rate decreased significantly with greater decreases the more frequent and the longer the training.

Heart rate reactivity associated to positive and negative food and non-food visual stimuli.

PubMed

Kuoppa, Pekka; Tarvainen, Mika P; Karhunen, Leila; Narvainen, Johanna

2016-08-01

Using food as a stimuli is known to cause multiple psychophysiological reactions. Heart rate variability (HRV) is common tool for assessing physiological reactions in autonomic nervous system. However, the findings in HRV related to food stimuli have not been consistent. In this paper the quick changes in HRV related to positive and negative food and non-food visual stimuli are investigated. Electrocardiogram (ECG) was measured from 18 healthy females while being stimulated with the pictures. Subjects also filled Three-Factor Eating Questionnaire to determine their eating behavior. The inter-beat-interval time series and the HRV parameters were extracted from the ECG. The quick change in HRV parameters were studied by calculating the change from baseline value (10 s window before stimulus) to value after the onset of the stimulus (10 s window during stimulus). The paired t-test showed significant difference between positive and negative food pictures but not between positive and negative non-food pictures. All the HRV parameters decreased for positive food pictures while they stayed the same or increased a little for negative food pictures. The eating behavior characteristic cognitive restraint was negatively correlated with HRV parameters that describe decreasing of heart rate.

Single unit activity in the medial prefrontal cortex during Pavlovian heart rate conditioning: Effects of peripheral autonomic blockade.

PubMed

Powell, D A; Ginsberg, Jay P

2005-11-01

Electrical activity was recorded from single neurons in the medial prefrontal cortex of rabbits during differential Pavlovian heart rate (HR) conditioning. A heterogeneous population of cells were found, some of which showed CS-evoked increases and others CS-evoked decreases in discharge, while some cells were biphasic. A subset of cells also showed trial-related changes in discharge that were related to acquisition of the HR discrimination between the reinforced CS+ and non-reinforced CS-. Administration of the peripheral cholinergic antagonist, methylscopolamine, and the andrenergic antagonist, atenolol, either increased or decreased maintained baseline activity of many cells, but had little or no effect on the CS-evoked activity of these cells. Waveform changes also did not result from administration of these drugs. This finding suggests that CS-evoked mPFC activity is not being driven by cardiac afferent input to CNS cardiac control centers. Previous studies have shown that ibotenic acid lesions of this area greatly decreases the magnitude of decelerative heart rate conditioned responses; the latter finding, plus the results of the present study, suggest that processing of CS/US contingencies by the prefrontal cortex contributes to the acquisition of autonomic changes during Pavlovian conditioning.

Increased Efferent Cardiac Sympathetic Nerve Activity and Defective Intrinsic Heart Rate Regulation in Type 2 Diabetes.

PubMed

Thaung, H P Aye; Baldi, J Chris; Wang, Heng-Yu; Hughes, Gillian; Cook, Rosalind F; Bussey, Carol T; Sheard, Phil W; Bahn, Andrew; Jones, Peter P; Schwenke, Daryl O; Lamberts, Regis R

2015-08-01

Elevated sympathetic nerve activity (SNA) coupled with dysregulated β-adrenoceptor (β-AR) signaling is postulated as a major driving force for cardiac dysfunction in patients with type 2 diabetes; however, cardiac SNA has never been assessed directly in diabetes. Our aim was to measure the sympathetic input to and the β-AR responsiveness of the heart in the type 2 diabetic heart. In vivo recording of SNA of the left efferent cardiac sympathetic branch of the stellate ganglion in Zucker diabetic fatty rats revealed an elevated resting cardiac SNA and doubled firing rate compared with nondiabetic rats. Ex vivo, in isolated denervated hearts, the intrinsic heart rate was markedly reduced. Contractile and relaxation responses to β-AR stimulation with dobutamine were compromised in externally paced diabetic hearts, but not in diabetic hearts allowed to regulate their own heart rate. Protein levels of left ventricular β1-AR and Gs (guanine nucleotide binding protein stimulatory) were reduced, whereas left ventricular and right atrial β2-AR and Gi (guanine nucleotide binding protein inhibitory regulatory) levels were increased. The elevated resting cardiac SNA in type 2 diabetes, combined with the reduced cardiac β-AR responsiveness, suggests that the maintenance of normal cardiovascular function requires elevated cardiac sympathetic input to compensate for changes in the intrinsic properties of the diabetic heart. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Cardiorespiratory interactions during resistive load breathing.

PubMed

Calabrese, P; Perrault, H; Dinh, T P; Eberhard, A; Benchetrit, G

2000-12-01

The addition to the respiratory system of a resistive load results in breathing pattern changes and in negative intrathoracic pressure increases. The aim of this study was to use resistive load breathing as a stimulus to the cardiorespiratory interaction and to examine the extent of the changes in heart rate variability (HRV) and respiratory sinus arrhythmia (RSA) in relation to the breathing pattern changes. HRV and RSA were studied in seven healthy subjects where four resistive loads were applied in a random order during the breath and 8-min recording made in each condition. The HRV spectral power components were computed from the R-R interval sequences, and the RSA amplitude and phase were computed from the sinusoid fitting the instantaneous heart rate within each breath. Adding resistive loads resulted in 1) increasing respiratory period, 2) unchanging heart rate, and 3) increasing HRV and changing RSA characteristics. HRV and RSA characteristics are linearly correlated to the respiratory period. These modifications appear to be linked to load-induced changes in the respiratory period in each individual, because HRV and RSA characteristics are similar at a respiratory period obtained either by loading or by imposed frequency breathing. The present results are discussed with regard to the importance of the breathing cycle duration in these cardiorespiratory interactions, suggesting that these interactions may depend on the time necessary for activation and dissipation of neurotransmitters involved in RSA.

Repeated change-of-direction test for collegiate male soccer players.

PubMed

Mizuguchi, S; Gray, H; Calabrese, L S; Haff, G G; Sands, W A; Ramsey, M W; Cardinale, M; Stone, M H

2014-08-01

The aim of the study was to investigate the applicability of a repeated change-of-direction (RCoD) test for NCAA Division-I male soccer players. The RCoD test consisted of 5 diagonal direction changes per repetition with a soccer ball to be struck at the end. Each player performed 15 repetitions with approximately 10 seconds to jog back between repetitions. Data were collected in two sessions. In the first session, 13 players were examined for heart rate responses and blood lactate concentrations. In the second session, 22 players were examined for the test's ability to discriminate the primary from secondary players (78.0±16.1 and 10.4±13.3 minutes per match, respectively). Heart rate data were available only from 9 players due to artifacts. The peak heart rate (200.2±6.6 beats∙min-1: 99.9±3.0% maximum) and blood lactate concentration (14.8±2.4 mmol∙L-1 immediately after) resulted in approximately 3.5 and 6.4-fold increases from the resting values, respectively. These values appear comparable to those during intense periods of soccer matches. In addition, the average repetition time of the test was found to discriminate the primary (4.85±0.23 s) from the secondary players (5.10±0.24 s) (P=0.02). The RCoD test appears to induce physiological responses similar to intense periods of soccer matches with respect to heart rate and blood lactate concentration. Players with better average repetition times tend to be those who play major minutes.

Occupational status and job stress in relation to cardiovascular stress reactivity in Japanese workers.

PubMed

Hirokawa, Kumi; Ohira, Tetsuya; Nagayoshi, Mako; Kajiura, Mitsugu; Imano, Hironori; Kitamura, Akihiko; Kiyama, Masahiko; Okada, Takeo; Iso, Hiroyasu

2016-12-01

This study aimed to investigate the effects of occupational status and job stress factors on cardiovascular stress reactivity in Japanese workers. In this baseline assessment between 2001 and 2009 in Osaka, Japan, we examined 928 healthy Japanese employees (330 men, 598 women) from two occupational statuses: managers/professionals and general workers. A brief job stress questionnaire was used to evaluate job stress levels. Systolic and diastolic blood pressure (SBP, DBP), heart rate, heart rate variability (high-frequency [HF], low-frequency [LF], LF/HF], and peripheral blood flow were measured at rest and during two stressful tasks. Changes in stress reactivity were calculated as the difference between the measured variables during the tasks and the rest period. Men showed inverse associations between quantitative job overload and DBP, heart rate, and LF/HF, between physical demands and blood pressure (SBP, DBP), and between a poor physical environment and HF. Men also had positive associations between qualitative job overload and heart rate, and between physical demands and peripheral blood flow (all p < 0.05). Women showed inverse associations between qualitative job overload and SBP, and showed positive associations between qualitative job overload and peripheral blood flow, and between a poor physical environment and SBP (all p < 0.05). When stratified by occupational status, significant associations between job stress and changes in stress reactivity were observed in male managers/professionals and female general workers (p < 0.05). Job stress levels are associated with changes in cardiovascular stress reactivity in men and women. Occupational status may modify these associations.

Change of Spectral Analysis of Fetal Heart Rate During Clinical Hypnosis: a Prospective Randomised Trial from the 20th Week of Gestation Till Term

PubMed Central

Reinhard, J.; Hayes-Gill, B. R.; Schiermeier, S.; Hatzmann, W.; Heinrich, T. M.; Hüsken-Janßen, H.; Herrmann, E.; Louwen, F.

2012-01-01

Objective: To investigate the functional adaptive process of the fetal autonomic nervous system during hypnosis from the 20th week of gestation till term. Are there changes in the power spectrum analysis of fetal heart rate when the mother is having a clinical hypnosis or control period? Study Design: Fourty-nine FHR recordings were analysed. Included recordings were from singletons and abdominal fetal ECG-monitored pregnancies. All women were randomised to receive clinical hypnosis followed by a period with no intervention or vice versa. Statistical analyses were performed with the Wilcoxon signed ranks and Spearman rho correlation tests. Results: There was a significant difference found between fetal heart rate at baseline (144.3 ± 6.0) and hypnosis (142.1 ± 6.4). A difference was also detected between the standard deviation of the heart rate between baseline (6.7 ± 1.9) and hypnosis (6.8 ± 3.5). LFnu was smaller during baseline (80.2 ± 5.3) than during hypnosis (82.1 ± 5.7), whereas HFnu was significantly larger (19.8 ± 5.3 vs. 17.9 ± 5.7). There was no correlation between the gestation age and the change in LFnu, HFnu or ratio LF/HF due to the hypnosis intervention. Conclusion: The functional adaptive process of the fetal autonomic system during hypnosis is reflected by a sympathovagal shift towards increased sympathetic modulation. PMID:25284838

Kangaroo care by fathers and mothers: comparison of physiological and stress responses in preterm infants.

PubMed

Srinath, B K; Shah, J; Kumar, P; Shah, P S

2016-05-01

To compare physiological and biochemical responses in stable preterm neonates and their parents following kangaroo mother care (KMC) and kangaroo father care (KFC). We conducted a prospective cross-over design study of stable preterm neonates of <35 weeks gestation in a tertiary Neonatal Unit in Toronto. All neonates received KMC and KFC for 1 h on consecutive days in a random order. Heart rate, temperature, blood pressure, oxygen saturation and salivary cortisol in infants before and after kangaroo care and heart rate, temperature and salivary cortisol in parents before and after kangaroo care were measured. Pairwise comparisons of changes in these measures were analyzed. Twenty-six sets of neonates and their parents were studied for physiological parameters, of which 19 had adequate samples for salivary cortisol assessment. The infants had a mean birth weight of 1096 g (s.d.=217) and a mean postmenstrual age at study of 32 weeks (s.d.=2). There were no significant differences in the changes in mean heart rate (P=0.51), temperature (P=0.37), oxygen saturation (P=0.50), systolic blood pressure (P=0.32), mean blood pressure (0.10) and salivary cortisol (P=0.50) before and after KMC or KFC in the neonates. The changes in mean heart rate (P=0.62), temperature (P=0.28) and salivary cortisol (P=0.59) before and after kangaroo care were similar between mothers and fathers. No significant differences in physiological and stress responses were identified following KMC or KFC in preterm neonates. KFC may be as safe and as effective as KMC.

Physiological responses to treadmill exercise and ambient temperature in normal and malignant hyperthermia susceptible pigs.

PubMed Central

D'Allaire, S; DeRoth, L

1986-01-01

Ten susceptible and ten resistant pigs to malignant hyperthermia were used to observe the effects of exercise and ambient temperature on selected physiological parameters. Pigs were submitted to a ten minute exercise on a treadmill operating at a speed of 1.8 km/h and inclined to 11 degrees. Exercise in the first group was at an ambient temperature of 14 degrees C, and in the second at 29 degrees C. The right carotid artery was previously cannulated for blood pressure measurements and for repeated blood sampling during exercise. Arterial pressure, heart rate, rectal and cutaneous temperatures were recorded. Levels of cortisol, creatine kinase and its isoenzymes were measured. At 14 degrees C, exercise caused some physiological adjustments in susceptible animals; heart rate, skin temperature and cortisol levels increased (P less than 0.05). In resistant pigs, only the heart rate was elevated significantly following exertional stress at 14 degrees C. Exercise at 29 degrees C produced severe stress and marked physiological changes: heart rate, rectal and skin temperatures and cortisol levels increased significantly in both susceptible and resistant swine. At 29 degrees C, susceptible pigs also had higher levels of serum cortisol, total creatine kinase and MM isoenzyme (P less than 0.05) compared to resistant pigs. The results indicate that, following exertional or thermal stress, susceptible pigs undergo more extensive physiological changes than do resistant pigs. Similar levels of stress prior to slaughter may trigger physiological changes which in the susceptible pigs would likely result in pale, soft exudative myopathy. PMID:3742362

Ivabradine, a novel heart rate slower: is it a sword of double blades in patients with idiopathic dilated cardiomyopathy?

PubMed

Rayan, Mona; Tawfik, Mazen; Alabd, Ali; Gamal, Amr

2011-08-01

To prospectively assess the safety and efficacy of ivabradine in patients with idiopathic dilated cardiomyopathy. We included 35 patients with idiopathic dilated cardiomyopathy with an ejection fraction (EF) <40% and heart rate >70 beats/min despite optimal medical therapy, according to the international guidelines in this prospective, non-randomized, single-arm, open-label safety study. Ivabradine was used as an add-on therapy to the maximally tolerated b-blocker in an increasing titrated dose till a target dose of 15 mg/day or resting heart rate of 60 beats/min for 3 months. During follow-up period the safety, patient tolerance and efficacy of this drug were assessed. All patients underwent 12-lead resting electrocardiography and Holter monitoring at inclusion and after 3 months. Statistical analysis was accomplished using paired t-test and Pearson correlation analysis. We found a significant reduction in the resting heart rate by a mean of 25.9 ± 9.4%, without a significant change of blood pressure. There was no prolongation of PR, QTc or QRS durations. Ventricular ectopic activity showed significant reduction (p<0.001). There was a significant correlation between the resting heart rate, NYHA and left ventricular ejection fraction (p<0.001 for both). One patient developed photopsia and decompensation was observed in another patient. Ivabradine is a safe and effective drug in reducing resting heart rate, improving NYHA functional class without undesirable effects on conduction parameters or ectopic activity.

Effect of maternal position on fetal behavioural state and heart rate variability in healthy late gestation pregnancy

PubMed Central

Burgess, Wendy; McIntyre, Jordan P. R.; Gunn, Alistair J.; Lear, Christopher A.; Bennet, Laura; Mitchell, Edwin A.; Thompson, John M. D.

2016-01-01

Key points Fetal behavioural state in healthy late gestation pregnancy is affected by maternal position.Fetal state 1F is more likely to occur in maternal supine or right lateral positions.Fetal state 4F is less likely to occur when the woman lies supine or semi‐recumbent.Fetal state change is more likely when the woman is supine or semi‐recumbent.Fetal heart rate variability is affected by maternal position with variability reduced in supine and semi‐recumbent positions. Abstract Fetal behavioural states (FBS) are measures of fetal wellbeing. In acute hypoxaemia, the human fetus adapts to a lower oxygen consuming state with changes in the cardiotocograph and reduced fetal activity. Recent studies of late gestation stillbirth described the importance of sleep position in the risk of intrauterine death. We designed this study to assess the effects of different maternal positions on FBS in healthy late gestation pregnancies under controlled conditions. Twenty‐nine healthy women had continuous fetal ECG recordings under standardized conditions in four randomly allocated positions, left lateral, right lateral, supine and semi‐recumbent. Two blinded observers, assigned fetal states in 5 min blocks. Measures of fetal heart rate variability were calculated from ECG beat to beat data. Compared to state 2F, state 4F was less likely to occur when women were semi‐recumbent [odds ratio (OR) = 0.11, 95% confidence interval (95% CI) 0.02, 0.55], and supine (OR = 0.27, 95% CI 0.07, 1.10). State 1F was more likely on the right (OR = 2.36, 95% CI 1.11, 5.04) or supine (OR = 4.99, 95% CI 2.41, 10.43) compared to the left. State change was more likely when the mother was semi‐recumbent (OR = 2.17, 95% CI 1.19, 3.95) or supine (OR = 2.67, 95% CI 1.46, 4.85). There was a significant association of maternal position to mean fetal heart rate. The measures of heart rate variability (SDNN and RMSSD) were reduced in both semi‐recumbent and supine positions. In healthy late gestation pregnancy, maternal position affects FBS and heart rate variability. These effects are likely fetal adaptations to positions which may produce a mild hypoxic stress. PMID:27871127

Effect of maternal position on fetal behavioural state and heart rate variability in healthy late gestation pregnancy.

PubMed

Stone, Peter R; Burgess, Wendy; McIntyre, Jordan P R; Gunn, Alistair J; Lear, Christopher A; Bennet, Laura; Mitchell, Edwin A; Thompson, John M D

2017-02-15

Fetal behavioural state in healthy late gestation pregnancy is affected by maternal position. Fetal state 1F is more likely to occur in maternal supine or right lateral positions. Fetal state 4F is less likely to occur when the woman lies supine or semi-recumbent. Fetal state change is more likely when the woman is supine or semi-recumbent. Fetal heart rate variability is affected by maternal position with variability reduced in supine and semi-recumbent positions. Fetal behavioural states (FBS) are measures of fetal wellbeing. In acute hypoxaemia, the human fetus adapts to a lower oxygen consuming state with changes in the cardiotocograph and reduced fetal activity. Recent studies of late gestation stillbirth described the importance of sleep position in the risk of intrauterine death. We designed this study to assess the effects of different maternal positions on FBS in healthy late gestation pregnancies under controlled conditions. Twenty-nine healthy women had continuous fetal ECG recordings under standardized conditions in four randomly allocated positions, left lateral, right lateral, supine and semi-recumbent. Two blinded observers, assigned fetal states in 5 min blocks. Measures of fetal heart rate variability were calculated from ECG beat to beat data. Compared to state 2F, state 4F was less likely to occur when women were semi-recumbent [odds ratio (OR) = 0.11, 95% confidence interval (95% CI) 0.02, 0.55], and supine (OR = 0.27, 95% CI 0.07, 1.10). State 1F was more likely on the right (OR = 2.36, 95% CI 1.11, 5.04) or supine (OR = 4.99, 95% CI 2.41, 10.43) compared to the left. State change was more likely when the mother was semi-recumbent (OR = 2.17, 95% CI 1.19, 3.95) or supine (OR = 2.67, 95% CI 1.46, 4.85). There was a significant association of maternal position to mean fetal heart rate. The measures of heart rate variability (SDNN and RMSSD) were reduced in both semi-recumbent and supine positions. In healthy late gestation pregnancy, maternal position affects FBS and heart rate variability. These effects are likely fetal adaptations to positions which may produce a mild hypoxic stress. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

The effect of spinal hyperbaric bupivacaine-fentanyl or hyperbaric bupivacaine on uterine tone and fetal heart rate in labouring women: a randomised controlled study.

PubMed

Kuberan, A; Jain, K; Bagga, R; Makkar, J K

2018-07-01

The mechanism for fetal heart rate abnormalities following spinal opioids remains controversial. We evaluated uterine tone, using an intra-uterine pressure catheter, and fetal heart rate abnormalities in 30 women in spontaneous labour with cervical dilation of 3-5 cm having combined spinal-epidural analgesia. Women were randomly assigned to receive a spinal with 2.0 mg hyperbaric bupivacaine plus 15 μg fentanyl, or 2.5 mg hyperbaric bupivacaine. The primary outcome measure was an increase > 10 mmHg in baseline uterine tone in the 30-min period following spinal injection. Only three (20%) women who had a bupivacaine-fentanyl spinal showed a > 10 mmHg increase in baseline tone vs. none who had bupivacaine (p = 0.63). The mean (SD) baseline uterine tone after the spinal injection was 13.3 (7.0) mmHg in the bupivacaine-fentanyl group and 7.7 (2.5) mmHg in the bupivacaine group (p = 0.01). Seven (47%) in the bupivacaine-fentanyl group showed new onset fetal heart rate changes during the 30-min period after the spinal, compared with two (13%) in the bupivacaine group (p = 0.04); however, these were transient and responded to intra-uterine resuscitation. Pain scores, sensory and motor block as well as neonatal outcomes were comparable between the groups. We found that raised baseline uterine tone was not more frequent when using bupivacaine-fentanyl rather than bupivacaine in the spinal component of combined spinal-epidural, although absolute values of baseline tone were higher, and fetal heart rate changes more frequent, in the former group. © 2018 The Association of Anaesthetists of Great Britain and Ireland.

Multicomponent exercise decreases blood pressure, heart rate and double product in normotensive and hypertensive older patients with high blood pressure.

PubMed

Coelho-Júnior, Hélio José; Asano, Ricardo Yukio; Gonçalvez, Ivan de Oliveira; Brietzke, Cayque; Pires, Flávio Oliveira; Aguiar, Samuel da Silva; Feriani, Daniele Jardim; Caperuto, Erico Chagas; Uchida, Marco Carlos; Rodrigues, Bruno

2018-02-26

The present study aimed to investigate the effects of a 6-month multicomponent exercise program on blood pressure, heart rate, and double product of uncontrolled and controlled normotensive and hypertensive older patients. The study included 183 subjects, 97 normotensives, of which 53 were controlled normotensives (CNS), and 44 uncontrolled normotensives (UNS), as well as 86 hypertensives, of which 43 were controlled hypertensives (CHS), and 43 uncontrolled hypertensives (UHS). Volunteers were recruited and blood pressure and heart rate measurements were made before and after a 6-month multicomponent exercise program. The program of physical exercise was performed twice a week for 26 weeks. The physical exercises program was based on functional and walking exercises. Exercise sessions were performed at moderate intensity. The results indicated that UHS showed a marked decrease in systolic (-8.0mmHg), diastolic (-11.1mmHg), mean (-10.1mmHg), and pulse pressures, heart rate (-6.8bpm), and double product (-1640bpmmmHg), when compared to baseline. Similarly, diastolic (-5.5mmHg) and mean arterial (-4.8mmHg) pressures were significantly decreased in UNS. Concomitantly, significant changes could be observed in the body mass index (-0.9kg/m 2 ; -1.5kg/m 2 ) and waist circumference (-3.3cm; only UHS) of UNS and UHS, which may be associated with the changes observed in blood pressure. In conclusion, the data of the present study indicate that a 6-month multicomponent exercise program may lead to significant reductions in blood pressure, heart rate, and double product of normotensive and hypertensive patients with high blood pressure values. Copyright © 2018 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

Effects of omega-3 fatty acids on resting heart rate, heart rate recovery after exercise, and heart rate variability in men with healed myocardial infarctions and depressed ejection fractions.

PubMed

O'Keefe, James H; Abuissa, Hussam; Sastre, Antonio; Steinhaus, David M; Harris, William S

2006-04-15

We explored possible mechanisms by which recommended intakes of omega-3 fatty acids may decrease the risk for sudden cardiac death in patients with documented coronary heart disease. The cardioprotective effects of omega-3 fatty acids have been documented in epidemiologic and randomized controlled trials. These fatty acids are presumed to decrease susceptibility to fatal arrhythmias, but whether this is mediated by classic risk factors or direct cardiac mechanisms is not known. Eighteen white men with a history of myocardial infarction and ejection fractions <40% were randomized to placebo or omega-3 fatty acids (585 mg of docosahexaenoic acid and 225 mg of eicosapentaenoic acid) for two 4-month periods in a crossover design. At the end of each period, heart rate (HR), HR variability, and rate of HR recovery after exercise were determined, as were effects on arterial compliance, blood pressure, cardiac function, and fasting serum levels of lipids and inflammatory markers. Omega-3 fatty acids decreased HR at rest from 73 +/- 13 to 68 +/- 13 beats/min (p <0.0001) and improved 1-minute HR recovery after exercise (-27 +/- 10 to -32 +/- 12 beats/min, p <0.01). HR variability in the high-frequency band increased (p <0.02), but no change was noted in overall HR variability. There were no significant effects on blood pressure, arterial compliance, lipids, or inflammatory markers. These changes are consistent with an increase in vagal activity and may in part explain the observed decrease in risk for sudden cardiac death seen with omega-3 fatty acid supplementation.

The Effect of Adenotonsillectomy for Childhood Sleep Apnea on Cardiometabolic Measures.

PubMed

Quante, Mirja; Wang, Rui; Weng, Jia; Rosen, Carol L; Amin, Raouf; Garetz, Susan L; Katz, Eliot; Paruthi, Shalini; Arens, Raanan; Muzumdar, Hiren; Marcus, Carole L; Ellenberg, Susan; Redline, Susan

2015-09-01

Obstructive sleep apnea syndrome (OSAS) has been associated with cardiometabolic disease in adults. In children, this association is unclear. We evaluated the effect of early adenotonsillectomy (eAT) for treatment of OSAS on blood pressure, heart rate, lipids, glucose, insulin, and C-reactive protein. We also analyzed whether these parameters at baseline and changes at follow-up correlated with polysomnographic indices. Data collected at baseline and 7-mo follow-up were analyzed from a randomized controlled trial, the Childhood Adenotonsillectomy Trial (CHAT). Clinical referral setting from multiple centers. There were 464 children, ages 5 to 9.9 y with OSAS without severe hypoxemia. Randomization to eAT or Watchful Waiting with Supportive Care (WWSC). There was no significant change of cardiometabolic parameters over the 7-mo interval in the eAT group compared to WWSC group. However, overnight heart rate was incrementally higher in association with baseline OSAS severity (average heart rate increase of 3 beats per minute [bpm] for apnea-hypopnea index [AHI] of 2 versus 10; [standard error = 0.60]). Each 5-unit improvement in AHI and 5 mmHg improvement in peak end-tidal CO2 were estimated to reduce heart rate by 1 and 1.5 bpm, respectively. An increase in N3 sleep also was associated with small reductions in systolic blood pressure percentile. There is little variation in standard cardiometabolic parameters in children with obstructive sleep apnea syndrome (OSAS) but without severe hypoxemia at baseline or after intervention. Of all measures, overnight heart rate emerged as the most sensitive parameter of pediatric OSAS severity. Clinicaltrials.gov (#NCT00560859). © 2015 Associated Professional Sleep Societies, LLC.

Hemodynamics of a functional centrifugal-flow total artificial heart with functional atrial contraction in goats.

PubMed

Shiga, Takuya; Shiraishi, Yasuyuki; Sano, Kyosuke; Taira, Yasunori; Tsuboko, Yusuke; Yamada, Akihiro; Miura, Hidekazu; Katahira, Shintaro; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yambe, Tomoyuki

2016-03-01

Implantation of a total artificial heart (TAH) is one of the therapeutic options for the treatment of patients with end-stage biventricular heart failure. There is no report on the hemodynamics of the functional centrifugal-flow TAH with functional atrial contraction (fCFTAH). We evaluated the effects of pulsatile flow by atrial contraction in acute animal models. The goats received fCFTAH that we created from two centrifugal-flow ventricular assist devices. Some hemodynamic parameters maintained acceptable levels: heart rate 115.5 ± 26.3 bpm, aortic pressure 83.5 ± 10.1 mmHg, left atrial pressure 18.0 ± 5.9 mmHg, pulmonary pressure 28.5 ± 9.7 mmHg, right atrial pressure 13.6 ± 5.2 mmHg, pump flow 4.0 ± 1.1 L/min (left) 3.9 ± 1.1 L/min (right), and cardiac index 2.13 ± 0.14 L/min/m(2). fCFTAH with atrial contraction was able to maintain the TAH circulation by forming a pulsatile flow in acute animal experiments. Taking the left and right flow rate balance using the low internal pressure loss of the VAD pumps may be easier than by other pumps having considerable internal pressure loss. We showed that the remnant atrial contraction effected the flow rate change of the centrifugal pump, and the atrial contraction waves reflected the heart rate. These results indicate that remnant atria had the possibility to preserve autonomic function in fCFTAH. We may control fCFTAH by reflecting the autonomic function, which is estimated with the flow rate change of the centrifugal pump.

Fractal mechanisms in the electrophysiology of the heart

NASA Technical Reports Server (NTRS)

Goldberger, A. L.

1992-01-01

The mathematical concept of fractals provides insights into complex anatomic branching structures that lack a characteristic (single) length scale, and certain complex physiologic processes, such as heart rate regulation, that lack a single time scale. Heart rate control is perturbed by alterations in neuro-autonomic function in a number of important clinical syndromes, including sudden cardiac death, congestive failure, cocaine intoxication, fetal distress, space sickness and physiologic aging. These conditions are associated with a loss of the normal fractal complexity of interbeat interval dynamics. Such changes, which may not be detectable using conventional statistics, can be quantified using new methods derived from "chaos theory.".

Influence of Heart Rate in Non-linear HRV Indices as a Sampling Rate Effect Evaluated on Supine and Standing.

PubMed

Bolea, Juan; Pueyo, Esther; Orini, Michele; Bailón, Raquel

2016-01-01

The purpose of this study is to characterize and attenuate the influence of mean heart rate (HR) on nonlinear heart rate variability (HRV) indices (correlation dimension, sample, and approximate entropy) as a consequence of being the HR the intrinsic sampling rate of HRV signal. This influence can notably alter nonlinear HRV indices and lead to biased information regarding autonomic nervous system (ANS) modulation. First, a simulation study was carried out to characterize the dependence of nonlinear HRV indices on HR assuming similar ANS modulation. Second, two HR-correction approaches were proposed: one based on regression formulas and another one based on interpolating RR time series. Finally, standard and HR-corrected HRV indices were studied in a body position change database. The simulation study showed the HR-dependence of non-linear indices as a sampling rate effect, as well as the ability of the proposed HR-corrections to attenuate mean HR influence. Analysis in a body position changes database shows that correlation dimension was reduced around 21% in median values in standing with respect to supine position ( p < 0.05), concomitant with a 28% increase in mean HR ( p < 0.05). After HR-correction, correlation dimension decreased around 18% in standing with respect to supine position, being the decrease still significant. Sample and approximate entropy showed similar trends. HR-corrected nonlinear HRV indices could represent an improvement in their applicability as markers of ANS modulation when mean HR changes.

Use of radiotelemetry to evaluate respiratory depression produced by chronic methadone administration.

PubMed

Lewanowitsch, Tanya; White, Jason M; Irvine, Rodney J

2004-01-26

Illicit and therapeutic opioid administration can result in overdose due to opioid-induced respiratory depression. Research investigating the respiratory depressant effects of opioids has been limited due to difficulties associated with acquiring long-term respiratory data. This study examined the novel use of radiotelemetry to measure respiratory rate, heart rate, locomotor activity and blood pressure in rats treated chronically with methadone. Over 4 days of treatment, respiratory rate decreased, but partial tolerance appeared to develop during active (night) periods. Decreased heart rate was observed during the night periods and tolerance appeared to develop to this effect. Activity and blood pressure did not change with treatment. The effects of naloxone hydrochloride and naloxone methiodide administration on the methadone-treated rats were also examined and both antagonists increased respiratory rate and heart rate, with only naloxone hydrochloride producing significant increases in activity. Radiotelemetry offers a means of evaluating drug effects on respiratory rate continually in ambulatory, unstressed animals.

A pilot randomized controlled trial of EKG for neonatal resuscitation

PubMed Central

Katheria, Anup; Arnell, Kathy; Brown, Melissa; Hassen, Kasim; Maldonado, Mauricio; Finer, Neil

2017-01-01

Background The seventh edition of the American Academy of Pediatrics Neonatal Resuscitation Program recommends the use of a cardiac monitor in infants that need resuscitation. Previous trials have shown that EKG heart rate is available before pulse rate from a pulse oximeter. To date no trial has looked at how the availability of electrocardiogram (EKG) affects clinical interventions in the delivery room. Objective To determine whether the availability of an EKG heart rate value and tracing to the clinical team has an effect on physiologic measures and related interventions during the stabilization of preterm infants. Design/Methods Forty (40) premature infants enrolled in a neuro-monitoring study (The Neu-Prem Trial: NCT02605733) who had an EKG monitor available were randomized to have the heart rate information from the bedside EKG monitor either displayed or not displayed to the clinical team. Heart rate, oxygen saturation, FiO2 and mean airway pressure from a data acquisition system were recorded every 2 seconds. Results were averaged over 30 seconds and the differences analyzed using two-tailed t-test. Interventions analyzed included time to first change in FiO2, first positive pressure ventilation, first increase in airway pressure, and first intubation. Results There were no significant differences in time to clinical interventions between the blinded and unblinded group, despite the unblinded group having access to a visible heart rate at 66 +/- 20 compared to 114 +/- 39 seconds for the blinded group (p < .0001). Pulse rate from oximeter was lower than EKG heart rate during the first 2 minutes of life, but this was not significant. Conclusion(s) EKG provides an earlier, and more accurate heart rate than pulse rate from an oximeter during stabilization of preterm infants, allowing earlier intervention. All interventions were started earlier in the unblinded EKG group but these numbers were not significant in this small trial. Earlier EKG placement before pulse oximeter placement may affect other interventions, but this needs further study. PMID:29099872

Is rate-pressure product of any use in the isolated rat heart? Assessing cardiac 'effort' and oxygen consumption in the Langendorff-perfused heart.

PubMed

Aksentijević, Dunja; Lewis, Hannah R; Shattock, Michael J

2016-02-01

What is the central question of this study? Rate-pressure product (RPP) is commonly used as an index of cardiac 'effort'. In canine and human hearts (which have a positive force-frequency relationship), RPP is linearly correlated with oxygen consumption and has therefore been widely adopted as a species-independent index of cardiac work. However, given that isolated rodent hearts demonstrate a negative force-frequency relationship, its use in this model requires validation. What is the main finding and its importance? Despite its widespread use, RPP is not correlated with oxygen consumption (or cardiac 'effort') in the Langendorff-perfused isolated rat heart. This lack of correlation was also evident when perfusions included a range of metabolic substrates, insulin or β-adrenoceptor stimulation. Langendorff perfusion of hearts isolated from rats and mice has been used extensively for physiological, pharmacological and biochemical studies. The ability to phenotype these hearts reliably is, therefore, essential. One of the commonly used indices of function is rate-pressure product (RPP); a rather ill-defined index of 'work' or, more correctly, 'effort'. Rate-pressure product, as originally described in dog or human hearts, was shown to be correlated with myocardial oxygen consumption (MV̇O2). Despite its widespread use, the application of this index to rat or mouse hearts (which, unlike the dog or human, have a negative force-frequency relationship) has not been characterized. The aim of this study was to examine the relationship between RPP and MV̇O2 in Langendorff-perfused rat hearts. Paced hearts (300-750 beats min(-1)) were perfused either with Krebs-Henseleit (KH) buffer (11 mm glucose) or with buffer supplemented with metabolic substrates and insulin. The arteriovenous oxygen consumption (MV̇O2) was recorded. Metabolic status was assessed using (31) P magnetic resonance spectroscopy and lactate efflux. Experiments were repeated in the presence of isoprenaline and in unpaced hearts where heart rate was increased by cumulative isoprenaline challenge. In KH buffer-perfused hearts, MV̇O2 increased with increasing heart rate, but given that left ventricular developed pressure decreased with increases in rate, RPP was not correlated with MV̇O2, lactate production or phosphocreatine/ATP ratio. Although the provision of substrates or β-adrenoceptor stimulation changed the shape of the RPP-MV̇O2 relationship, neither intervention resulted in a positive correlation between RPP and oxygen consumption. Rate-pressure product is therefore an unreliable index of oxygen consumption or 'cardiac effort' in the isolated rat heart. © 2015 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

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.

Emotional and cognitive changes during and post a near fatal heart attack and one-year after: a case study.

PubMed

Lane, Andrew M; Godfrey, Richard

2010-01-01

This case study reports on changes in emotions before and during an unexpected heart rate in a young, apparently healthy male with a life-long history of exercise in the absence of family history of heart problems. He completed the Brunel Mood Scale (Terry et al. , 2003) to assess emotions before, during, and after the heart attack, and also describing his thoughts during these periods. Results indicate he experienced unpleasant emotions in the build up to the heart attack, feelings he attributed at the time to frustration to achieve fitness goals. He maintained an exercise regime prior to having a heart attack, a finding consistent with previous research suggesting that early diagnosis, although vital for survival, is not likely to be identified among seemingly healthy individuals. During the heart attack, he experienced a rapid emotional change characterised by a rapid increase in anger coupled with thoughts of needing to survive. The intensity of emotions and regulation strategies employed before and during the heart attack provide insight this experience, and we suggest future research should investigate emotional change during adverse conditions. Key pointsThe present case study details emotions experienced and attempts to regulate these emotions before, during and post a heart attack. Unpleasant emotions experienced before the heart were attributed to lack of progress toward fitness goals, a perception that is plausible as he was a regular exerciser.Early identification of heart attack is critical as "Time is Muscle" (Whyte et al., 2009) and therefore even people perceived to be at low risk should consider the possibility of such an eventuality, and seek medical treatment early in the process.

Yoga Nidra relaxation increases heart rate variability and is unaffected by a prior bout of Hatha yoga.

PubMed

Markil, Nina; Whitehurst, Michael; Jacobs, Patrick L; Zoeller, Robert F

2012-10-01

The measurement of heart rate variability (HRV) is often applied as an index of autonomic nervous system (ANS) balance and, therefore, myocardial stability. Previous studies have suggested that relaxation or mind-body exercise can influence ANS balance positively as measured by HRV but may act via different mechanisms. No studies, to the authors' knowledge, have examined the acute response in HRV to interventions combining relaxation and mind-body exercise. The objective of this study was to compare the acute HRV responses to Yoga Nidra relaxation alone versus Yoga Nidra relaxation preceded by Hatha yoga. This was a randomized counter-balanced trial. The trial was conducted in a university exercise physiology laboratory. Subjects included 20 women and men (29.15±6.98 years of age, with a range of 18-47 years). Participants completed a yoga plus relaxation (YR) session and a relaxation only (R) session. The YR condition produced significant changes from baseline in heart rate (HR; beats per minute [bpm], p<0.001) and indices of HRV: R-R (ms, p<0.001), pNN50 (%, p=0.009), low frequency (LF; %, p=0.008) and high frequency (HF; %, p=0.035). The R condition produced significant changes from baseline in heart rate (bpm, p<0.001) as well as indices of HRV: R-R (ms, p<0.001), HF (ms(2), p=0.004), LF (%, p=0.005), HF (%, p=0.008) and LF:HF ratio (%, p=0.008). There were no significant differences between conditions at baseline nor for the changes from baseline for any of the variables. These changes demonstrate a favorable shift in autonomic balance to the parasympathetic branch of the ANS for both conditions, and that Yoga Nidra relaxation produces favorable changes in measures of HRV whether alone or preceded by a bout of Hatha yoga.

Effects of concurrent physical and cognitive demands on muscle activity and heart rate variability in a repetitive upper-extremity precision task.

PubMed

Srinivasan, Divya; Mathiassen, Svend Erik; Hallman, David M; Samani, Afshin; Madeleine, Pascal; Lyskov, Eugene

2016-01-01

Most previous studies of concurrent physical and cognitive demands have addressed tasks of limited relevance to occupational work, and with dissociated physical and cognitive task components. This study investigated effects on muscle activity and heart rate variability of executing a repetitive occupational task with an added cognitive demand integral to correct task performance. Thirty-five healthy females performed 7.5 min of standardized repetitive pipetting work in a baseline condition and a concurrent cognitive condition involving a complex instruction for correct performance. Average levels and variabilities of electromyographic activities in the upper trapezius and extensor carpi radialis (ECR) muscles were compared between these two conditions. Heart rate and heart rate variability were also assessed to measure autonomic nervous system activation. Subjects also rated perceived fatigue in the neck-shoulder region, as well as exertion. Concurrent cognitive demands increased trapezius muscle activity from 8.2% of maximum voluntary exertion (MVE) in baseline to 9.0% MVE (p = 0.0005), but did not significantly affect ECR muscle activity, heart rate, heart rate variability, perceived fatigue or exertion. Trapezius muscle activity increased by about 10%, without any accompanying cardiovascular response to indicate increased sympathetic activation. We suggest this slight increase in trapezius muscle activity to be due to changed muscle activation patterns within or among shoulder muscles. The results suggest that it may be possible to introduce modest cognitive demands necessary for correct performance in repetitive precision work without any major physiological effects, at least in the short term.

Cardiovascular changes in video-game players. Cause for concern?

PubMed

Gwinup, G; Haw, T; Elias, A

1983-12-01

Video games are one of the most popular recreational activities among Americans of all ages, especially teenaged boys and young men. Studies of the health hazards of video-game playing have linked seizures, psychologic disturbances, and other health problems with the games. The study reported here measured changes in blood pressure and heart rate that occurred in 23 young men when they played a video game. The mean systolic blood pressure for the entire group was considerably higher during play than before or after and was significantly higher in novice players than in more skilled players. Heart rate was also significantly higher during play. In view of these results, other cardiovascular changes might be expected to occur during video-game playing. Although the changes reported here were minor, even minor cardiovascular alterations could potentially prove serious in persons with cardiovascular disease.

Heart rate profile during exercise in patients with early repolarization.

PubMed

Cay, Serkan; Cagirci, Goksel; Atak, Ramazan; Balbay, Yucel; Demir, Ahmet Duran; Aydogdu, Sinan

2010-09-01

Both early repolarization and altered heart rate profile are associated with sudden death. In this study, we aimed to demonstrate an association between early repolarization and heart rate profile during exercise. A total of 84 subjects were included in the study. Comparable 44 subjects with early repolarization and 40 subjects with normal electrocardiogram underwent exercise stress testing. Resting heart rate, maximum heart rate, heart rate increment and decrement were analyzed. Both groups were comparable for baseline characteristics including resting heart rate. Maximum heart rate, heart rate increment and heart rate decrement of the subjects in early repolarization group had significantly decreased maximum heart rate, heart rate increment and heart rate decrement compared to control group (all P < 0.05). The lower heart rate increment (< 106 beats/min) and heart rate decrement (< 95 beats/min) were significantly associated with the presence of early repolarization. After adjustment for age and sex, the multiple-adjusted OR of the risk of presence of early repolarization was 2.98 (95%CI 1.21-7.34) (P = 0.018) and 7.73 (95%CI 2.84-21.03) (P < 0.001) for the lower heart rate increment and heart rate decrement compared to higher levels, respectively. Subjects with early repolarization have altered heart rate profile during exercise compared to control subjects. This can be related to sudden death.

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 examine the cardiovascular system may thus lead to new insight with respect to fetal development.

Mitochondrial fatty acid oxidation alterations in heart failure, ischaemic heart disease and diabetic cardiomyopathy

PubMed Central

Fillmore, N; Mori, J; Lopaschuk, G D

2014-01-01

Heart disease is a leading cause of death worldwide. In many forms of heart disease, including heart failure, ischaemic heart disease and diabetic cardiomyopathies, changes in cardiac mitochondrial energy metabolism contribute to contractile dysfunction and to a decrease in cardiac efficiency. Specific metabolic changes include a relative increase in cardiac fatty acid oxidation rates and an uncoupling of glycolysis from glucose oxidation. In heart failure, overall mitochondrial oxidative metabolism can be impaired while, in ischaemic heart disease, energy production is impaired due to a limitation of oxygen supply. In both of these conditions, residual mitochondrial fatty acid oxidation dominates over mitochondrial glucose oxidation. In diabetes, the ratio of cardiac fatty acid oxidation to glucose oxidation also increases, although primarily due to an increase in fatty acid oxidation and an inhibition of glucose oxidation. Recent evidence suggests that therapeutically regulating cardiac energy metabolism by reducing fatty acid oxidation and/or increasing glucose oxidation can improve cardiac function of the ischaemic heart, the failing heart and in diabetic cardiomyopathies. In this article, we review the cardiac mitochondrial energy metabolic changes that occur in these forms of heart disease, what role alterations in mitochondrial fatty acid oxidation have in contributing to cardiac dysfunction and the potential for targeting fatty acid oxidation to treat these forms of heart disease. LINKED ARTICLES This article is part of a themed issue on Mitochondrial Pharmacology: Energy, Injury & Beyond. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2014.171.issue-8 PMID:24147975

Effect of electromagnetic field accompanying the magnetic resonance imaging on human heart rate variability - a pilot study.

PubMed

Derkacz, Arkadiusz; Gawrys, Jakub; Gawrys, Karolina; Podgorski, Maciej; Magott-Derkacz, Agnieszka; Poreba, Rafał; Doroszko, Adrian

2018-06-01

The effect of electromagnetic field on cardiovascular system in the literature is defined in ambiguous way. The aim of this study was to evaluate the effect of electromagnetic field on the heart rate variability (HRV) during the examination with magnetic resonance. Forty-two patients underwent Holter ECG heart monitoring for 30 minutes twice: immediately before and after the examination with magnetic resonance imaging (MRI). HRV was analysed by assessing a few selected time and spectral parameters. Is has been shown that standard deviation of NN intervals (SDNN) and very low frequency rates increased, whereas the low frequency:high frequency parameter significantly decreased following the MRI examination. These results show that MRI may affect the HRV most likely by changing the sympathetic-parasympathetic balance.

Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

NASA Technical Reports Server (NTRS)

Wilson, T. E.; Cui, J.; Crandall, C. G.

2001-01-01

1. Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. 2. In seven subjects mean arterial blood pressure was lowered (approximately 8 mmHg) and then raised (approximately 13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). 3. Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 +/- 3 to 92 +/- 4 beats x min(-1); P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 +/- 4 to 68 +/- 4 beats x min(-1); P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. 4. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. 5. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals.

Symptom rating scale for assessing hyperthyroidism.

PubMed

Klein, I; Trzepacz, P T; Roberts, M; Levey, G S

1988-02-01

A hyperthyroid symptom scale (HSS) was designed and administered to ten subjects with untreated Graves' disease. All subjects had clinical and chemical evidence of hyperthyroidism and reproducible HSS scores of 20 or more points. During sequential treatments with propranolol hydrochloride (phase 2) followed by propylthiouracil (phase 3) there was a significant decline in the HSS scores at each phase. Accompanying the decrease in HSS scores was a decrease in heart rate, but there was no change in thyroid function test results at phase 2 and a decrease in heart rate, thyroid function test results, and goiter size at phase 3. This new scale includes ten categories of symptoms, it is sensitive to changes in both the adrenergic and metabolic components of hyperthyroidism, and it is useful in the clinical assessment and management of patients with thyrotoxicosis.

Association of heart rate profile during exercise with the severity of coronary artery disease.

PubMed

Cay, Serkan; Ozturk, Sezgin; Biyikoglu, Funda; Yildiz, Abdulkadir; Cimen, Tolga; Uygur, Belma; Tuna, Funda

2009-05-01

Coronary artery disease is the leading cause of morbidity and mortality around the world. Autonomic nervous system abnormalities are associated with coronary artery disease and its complications. Exercise stress tests are routinely used for the detection of the presence of coronary artery disease. In this study, we observed the association between heart rate profile during exercise and the severity of coronary artery disease. One hundred and sixty patients with abnormal exercise treadmill test (> or =1 mm horizontal or downsloping ST-segment depression; 119 men, 41 women; mean age = 57 +/- 9 years) were included in the study. Use of any drug affecting heart rate was not permitted. Resting heart rate before exercise, maximum heart rate during exercise, and resting heart rate after exercise (5 min later) were measured and two parameters were calculated: heart rate increment (maximum heart rate - resting heart rate before exercise) and heart rate decrement (maximum heart rate - resting heart rate after exercise). All patients underwent selective coronary angiography and subclassified into two groups according to stenotic lesion severity. Group 1 had at least 50% of stenotic lesion and group 2 had less than 50%. Patients in the first group had increased resting heart rate, decreased maximum heart rate, decreased heart rate increment, and decreased heart rate decrement compared with second group. All patients were classified into tertiles of resting heart rate, heart rate increment, and heart rate decrement level to evaluate whether these parameters were associated with severity of coronary artery stenosis in the study. The multiple-adjusted odds ratio of the risk of severe coronary atherosclerosis was 21.888 (95% confidence interval 6.983-68.606) for the highest tertile of resting heart rate level compared with the lowest tertile. In addition, the multiple-adjusted odds ratio of the risk of severe coronary atherosclerosis was 20.987 (95% confidence interval 6.635-66.387) for the lowest tertile of heart rate increment level compared with the highest tertile and 2.360 (95% confidence interval 1.004-5.544) for the lowest tertile of heart rate decrement level compared with the highest tertile. Altered autonomic nervous system regulation affects heart rate profile, increased resting heart rate, decreased heart rate increment, and decreased heart rate decrement, during exercise and this effect is strongly and independently associated with the severity of coronary artery disease.

National trends in rates of death and hospital admissions related to acute myocardial infarction, heart failure and stroke, 1994–2004

PubMed Central

Tu, Jack V.; Nardi, Lorelei; Fang, Jiming; Liu, Juan; Khalid, Laila; Johansen, Helen

2009-01-01

Background Rates of death from cardiovascular and cerebrovascular diseases have been steadily declining over the past few decades. Whether such declines are occurring to a similar degree for common disorders such as acute myocardial infarction, heart failure and stroke is uncertain. We examined recent national trends in mortality and rates of hospital admission for these 3 conditions. Methods We analyzed mortality data from Statistic Canada’s Canadian Mortality Database and data on hospital admissions from the Canadian Institute for Health Information’s Hospital Morbidity Database for the period 1994–2004. We determined age- and sex-standardized rates of death and hospital admissions per 100 000 population aged 20 years and over as well as in-hospital case-fatality rates. Results The overall age- and sex-standardized rate of death from cardiovascular disease in Canada declined 30.0%, from 360.6 per 100 000 in 1994 to 252.5 per 100 000 in 2004. During the same period, the rate fell 38.1% for acute myocardial infarction, 23.5% for heart failure and 28.2% for stroke, with improvements observed across most age and sex groups. The age- and sex-standardized rate of hospital admissions decreased 27.6% for stroke and 27.2% for heart failure. The rate for acute myocardial infarction fell only 9.2%. In contrast, the relative decline in the inhospital case-fatality rate was greatest for acute myocardial infarction (33.1%; p < 0.001). Much smaller relative improvements in case-fatality rates were noted for heart failure (8.1%) and stroke (8.9%). Interpretation The rates of death and hospital admissions for acute myocardial infarction, heart failure and stroke in Canada changed at different rates over the 10-year study period. Awareness of these trends may guide future efforts for health promotion and health care planning and help to determine priorities for research and treatment. PMID:19546444

Change in heart rate variability after the adult attachment interview in dissociative patients.

PubMed

Farina, Benedetto; Speranza, Anna Maria; Imperatori, Claudio; Quintiliani, Maria Isabella; Della Marca, Giacomo

2015-01-01

The aim of this study was to assess heart rate variability (HRV) in individuals with dissociative disorders (DD) before and after the Adult Attachment Interview (AAI). Electrocardiograms were recorded before, during, and after the AAI in 13 individuals with DD and 13 healthy participants matched for age and gender. Significant change in HRV was observed only in the DD group. After the AAI, those with DD showed significant increases in the low frequency/high frequency ratio (pre-AAI = 1.91 ± 1.19; post-AAI = 4.03 ± 2.40; Wilcoxon test = -2.76, p = .005). Our results suggest that the retrieval of childhood attachment experiences in individuals with DD is associated with a change in HRV patterns that could reflect the emotion dysregulation of dissociative psychopathological processes.

Changes in Systolic Blood Pressure during Isometric Contractions of Different Size Muscle Groups.

DTIC Science & Technology

1979-05-01

and 7 bea’s/min in heart rate. The moan aortic pressure and heart rate of three of the four I subiec’s ramained in a steady skate condition during the...mass because of its relative ease of motor control. Even though it is fairly easy to isolate this movement, if stabilized properly, it Istill remains...flexion), fine motor control is required to produce index finger adduction as an isolated i contraction (37,38). with this in mind, one should

Monitoring nocturnal heart rate with bed sensor.

PubMed

Migliorini, M; Kortelainen, J M; Pärkkä, J; Tenhunen, M; Himanen, S L; Bianchi, A M

2014-01-01

This article is part of the Focus Theme of Methods of Information in Medicine on "Biosignal Interpretation: Advanced Methods for Studying Cardiovascular and Respiratory Systems". The aim of this study is to assess the reliability of the estimated Nocturnal Heart Rate (HR), recorded through a bed sensor, compared with the one obtained from standard electrocardiography (ECG). Twenty-eight sleep deprived patients were recorded for one night each through matrix of piezoelectric sensors, integrated into the mattress, through polysomnography (PSG) simultaneously. The two recording methods have been compared in terms of signal quality and differences in heart beat detection. On average, coverage of 92.7% of the total sleep time was obtained for the bed sensor, testifying the good quality of the recordings. The average beat-to-beat error of the inter-beat intervals was 1.06%. These results suggest a good overall signal quality, however, considering fast heart rates (HR > 100 bpm), performances were worse: in fact, the sensitivity in the heart beat detection was 28.4% while the false positive rate was 3.8% which means that a large amount of fast beats were not detected. The accuracy of the measurements made using the bed sensor has less than 10% of failure rate especially in periods with HR lower than 70 bpm. For fast heart beats the uncertainty increases. This can be explained by the change in morphology of the bed sensor signal in correspondence of a higher HR.

Diminution of Heart Rate Variability in Bipolar Depression

PubMed Central

Hage, Brandon; Britton, Briana; Daniels, David; Heilman, Keri; Porges, Stephen W.; Halaris, Angelos

2017-01-01

Autonomic nervous system (ANS) dysregulation in depression is associated with symptoms associated with the ANS. The beat-to-beat pattern of heart rate defined as heart rate variability (HRV) provides a noninvasive portal to ANS function and has been proposed to represent a means of quantifying resting vagal tone. We quantified HRV in bipolar depressed (BDD) patients as a measure of ANS dysregulation seeking to establish HRV as a potential diagnostic and prognostic biomarker for treatment outcome. Forty-seven BDD patients were enrolled. They were randomized to receive either escitalopram–celecoxib or escitalopram-placebo over 8 weeks in a double-blind study design. Thirty-five patients completed the HRV studies. Thirty-six healthy subjects served as controls. HRV was assessed at pretreatment and end of study and compared with that of controls. HRV was quantified and corrected for artifacts using an algorithm that incorporates time and frequency domains to address non-stationarity of the beat-to-beat heart rate pattern. Baseline high frequency-HRV (i.e., respiratory sinus arrhythmia) was lower in BDD patients than controls, although the difference did not reach significance. Baseline low-frequency HRV was significantly lower in BDD patients (ln4.20) than controls (ln = 5.50) (p < 0.01). Baseline heart period was significantly shorter (i.e., faster heart rate) in BDD patients than controls. No significant change in HRV parameters were detected over the course of the study with either treatment. These findings suggest that components of HRV may be diminished in BDD patients. PMID:29270399

Episodes of apnea and bradycardia in the preterm newborn: impact on cerebral oxygenation measured by near-infrared spectrophotometry

NASA Astrophysics Data System (ADS)

Van Huffel, Sabine; Craemers, Johan; Lenaerts, Bart; Daniels, Hans; Naulaers, Gunnar; Casaer, Paul

1998-12-01

The objective of this study is to evaluate the effect of episodes of apneas and/or mild bradycardia (heart rate decreases of 10 to 20% or more) on cerebral oxyhemoglobin (HbO2) and reduced hemoglobin (Hb) concentration as measured by Near Infrared Spectrophotometry (NIRS). Measurements were carried out on 7 preterm infants who experienced apneic and bradycardiac events. It is shown how to characterize these events using time-frequency analysis. In addition to NIRS (performed with a NIRO-500 from Hamamatsu, Japan), the heart rate, ECG, peripheral arterial oxygen saturation (measured at the foot) and respiration (abdominal and thoracic pressure, and nasal airflow) were continuously recorded. The impact of apneic events and periodic breathing on these measurements reveals the clinical relevance of NIRS. In particular, we investigate whether these changes in heart rate and respiration also influence HbO2 and reduced Hb concentration in neonatal brain. These changes are characterized, as well as their relationships with the other simultaneously recorded signals such as peripheral arterial oxygen saturation.

Changes in Physiological Parameters Induced by Indoor Simulated Driving: Effect of Lower Body Exercise at Mid-Term Break

PubMed Central

Liang, Wen Chieh; Yuan, John; Sun, Deh Chuan; Lin, Ming Han

2009-01-01

The study monitored physiological parameter changes after 120-min of simulated driving. Blood pressures, heart rate (HR), heart rate variability (HRV) and palm temperatures were measured using an ANSWatch® monitor. Subjects were divided into two groups (A & B). Both groups performed 2-hour driving, but group B additionally took a 15-min exercise break. Heart rate, systolic pressure, LF/HF, and palm temperature decreased for group A after driving; for group B only HR and palm temperatures decreased. HRV and parasympathetic indices HF(AU) and HF(NU) increased for group A, while HRV and sympathetic index LF(AU) increased in group B. Group A had higher fatigue scores than group B. ANS activation may overcome some fatigue symptoms, but the recovery is nonetheless incomplete. Exercise break is proven to be an effective remedy, especially if accompanied by the ANS actions. The normalized parasympathetic index HF(NU), the normalized sympathetic index LF(NU), and the sympatho-vagal balance index LF/HF are three most promising parameters that could be further developed to monitor driver fatigue. PMID:22399979

Effect of tocolytic drugs on fetal heart rate variability: a systematic review.

PubMed

Verdurmen, Kim M J; Hulsenboom, Alexandra D J; van Laar, Judith O E H; Oei, S Guid

2017-10-01

Tocolytics may cause changes in fetal heart rate (HR) pattern, while fetal heart rate variability (HRV) is an important marker of fetal well-being. We aim to systematically review the literature on how tocolytic drugs affect fetal HRV. We searched CENTRAL, PubMed and EMBASE up to June 2016. Studies published in English, using computerized or visual analysis to describe the effect of tocolytics on HRV in human fetuses were included. Studies describing tocolytics during labor, external cephalic version, pre-eclampsia and infection were excluded. Eventually, we included six studies, describing 169 pregnant women. Nifedipine, atosiban and indomethacin administration show no clinically important effect on fetal HRV. Following administration of magnesium sulfate decreased variability and cases of bradycardia are described. Fenoterol administration results in a slight increase in fetal HR with no changes in variability. After ritodrine administration increased fetal HR and decreased variability is seen. The effect of co-administration of corticosteroids should be taken into account. In order to prevent iatrogenic preterm labor, the effects of tocolytic drugs on fetal HRV should be taken into account when monitoring these fetuses.

[Stress parameters and behaviour of horses in walkers with and without the use of electricity].

PubMed

Giese, C; Gerber, V; Howald, M; Bachmann, I; Burger, D

2014-04-01

In order to investigate stress responses of horses in walkers with and without electricity, 12 horses were trained during 3 weeks in a horse walker with and without the use of electricity (3.7 kV). To evaluate the stress response, cortisol levels in the blood were measured, the heart rate was monitored using the Polar® system and the behaviour was evaluated. Neither the cortisol levels nor the heart rates showed any relevant statistically significant difference between horses moved in the horse walker with or without the use of electricity. The highest cortisol levels and heart rates were recorded during the first week (habituation period). A significant difference could be observed regarding spontaneous compartment changes: while this happened mainly during the first week and before the first use of electricity, no horses changed compartments in the periods when electricity was used and thereafter. The results of this study indicate that the use of electricity in the horse walker does not seem to cause significant detectable stress in the horses.

Survival After Rate-Responsive Programming in Patients With Cardiac Resynchronization Therapy-Defibrillator Implants Is Associated With a Novel Parameter: The Heart Rate Score.

PubMed

Olshansky, Brian; Richards, Mark; Sharma, Arjun; Wold, Nicholas; Jones, Paul; Perschbacher, David; Wilkoff, Bruce L

2016-08-01

Rate-responsive pacing (DDDR) versus nonrate-responsive pacing (DDD) has shown no survival benefit for patients undergoing cardiac resynchronization therapy defibrillator (CRT-D) implants. The heart rate score (HRSc), an indicator of heart rate variation, may predict survival. We hypothesized that high-risk HRSc CRT-D patients will have improved survival with DDDR versus DDD alone. All CRT-D patients in LATITUDE remote monitoring (2006-2011), programmed DDD, had HRSc calculated at first data upload after implant (median 1.4 months). Patients subsequently reprogrammed to DDDR 7.6 median months later were compared with a propensity-matched DDD group and followed for 21.4 median months by remote monitoring. Data were adjusted for age, sex, lower rate limit, percent atrial pacing, percent biventricular pacing, and implant year. The social security death index was used to identify deaths. Remote monitoring provided programming and histogram data. DDDR programming in CRT-D patients was associated with improved survival (adjusted hazard ratio =0.77; P<0.001). However, only those with baseline HRSc ≥70% (2308/6164) had improved HRSc with DDDR (from 88±9% to 78±15%; P<0.001) and improved survival (hazard ratio =0.74; P<0.001). Patients with a high baseline HRSc and significant improvement over time were more likely to survive (hazard ratio =0.63; P=0.006). For patients with HRSc <70%, DDDR reprogramming increased the HRSc from 46±11% to 50±15% (P<0.001); survival did not change. The HRSc did not change with DDD pacing over time. In CRT-D patients with HRSc ≥70%, DDDR reprogramming improved the HRSc and was associated with survival. Patients with lower HRSc had no change in survival with DDDR programming. © 2016 American Heart Association, Inc.

Quantifying the Physiological Stress Response to Simulated Maritime Pilotage Tasks: The Influence of Task Complexity and Pilot Experience.

PubMed

Main, Luana C; Wolkow, Alexander; Chambers, Timothy P

2017-11-01

The aim of this study was to quantify the stress associated with performing maritime pilotage tasks in a high-fidelity simulator. Eight trainee and 13 maritime pilots completed two simulated pilotage tasks of varying complexity. Salivary cortisol samples were collected pre- and post-simulation for both trials. Heart rate was measured continuously throughout the study. Significant changes in salivary cortisol (P = 0.000, η = 0.139), average (P = 0.006, η = 0.087), and peak heart rate (P = 0.013, η = 0.077) from pre- to postsimulation were found. Varying task complexity did partially influence stress response; average (P = 0.016, η = 0.026) and peak heart rate (P = 0.034, η = 0.020) were higher in the experimental condition. Trainees also recorded higher average (P = 0.000, η = 0.054) and peak heart rates (P = 0.027, η = 0.022). Performing simulated pilotage tasks evoked a measurable stress response in both trainee and expert maritime pilots.

Influence of Prolonged Spaceflight on Heart Rate and Oxygen Uptake Kinetics

NASA Astrophysics Data System (ADS)

Hoffmann, U.; Moore, A.; Drescher, U.

2013-02-01

During prolonged spaceflight, physical training is used to minimize cardiovascular deconditioning. Measurement of the kinetics of cardiorespiratory parameters, in particular the kinetic analysis of heart rate, respiratory and muscular oxygen uptake, provides useful information with regard to the efficiency and regulation of the cardiorespiratory system. Practically, oxygen uptake kinetics can only be measured at the lung site (V’O2 resp). The dynamics of V’O2 resp, however, is not identical with the dynamics at the site of interest: skeletal muscle. Eight Astronauts were tested pre- and post-flight using pseudo random binary workload changes between 30 and 80 W. Their kinetic responses of heart rate, respiratory as well as muscular V’O2 kinetics were estimated by using time-series analysis. Statistical analysis revealed that the kinetic responses of respiratory as well as muscular V’O2 kinetics are slowed post-flight than pre-flight. Heart rate seems not to be influenced following flight. The influence of other factors (e. g. astronauts’ exercise training) may impact these parameters and is an area for future studies.

The effect of relaxing massage on heart rate and heart rate variability in purebred Arabian racehorses.

PubMed

Kowalik, Sylwester; Janczarek, Iwona; Kędzierski, Witold; Stachurska, Anna; Wilk, Izabela

2017-04-01

The objective of this study was to assess the effect of relaxing massage on the heart rate (HR) and heart rate variability (HRV) in young racehorses during their first racing season. In the study, 72 Purebred Arabian racehorses were included. The study was implemented during the full race season. The horses from control and experimental groups were included in regular race training 6 days a week. The horses from the experimental group were additionally subject to the relaxing massage 3 days a week during the whole study. HR and HRV were assumed as indicators of the emotional state of the horses. The measurements were taken six times, every 4-5 weeks. The HRV parameters were measured at rest, during grooming and saddling the horse and during warm-up walking under a rider. The changes of the parameters throughout the season suggest that the relaxing massage may be effectively used to make the racehorses more relaxed and calm. Moreover, the horses from the experimental group had better race performance records. © 2016 Japanese Society of Animal Science.

Effects of a Taser: Conducted Energy Weapon on the Circulating Red-Blood-Cell Population and Other Factors in Sus scrofa

DTIC Science & Technology

2013-03-30

canvas sling. Heart rate, respiration rate, and oxygen saturation were monitored continuously using a pulse oximeter (VetOx G2 Digital, Heska Corporation...Pre Post 30 min Mean SD Median Range Mean SD Median Range Mean SD Median Range Oxygen saturation % 93.7 2.1 93.7 91–97 63.2* 17.4 66.5 36.7–91.3 92.2...as actin in human RBC membranes [29] and human neutrophils [34]. Discussion General findings Changes in heart rate, venous-blood oxygen saturation

A microprocessor-based cardiotachometer

NASA Technical Reports Server (NTRS)

Donaldson, J. A.; Crosier, W. G.

1979-01-01

The development of a highly accurate and reliable cardiotachometer for measuring the heart rate of test subjects is discussed. It measures heart rate over the range of 30 to 250 beats/minute and gives instantaneous (beat to beat) updates on the system output so that occasional noise artifacts or ectopic beats could be more easily identified except that occasional missed beats caused by switching ECG leads should not cause a change in the output. The cardiotachometer uses an improved analog filter and R-wave detector and an Intel 8080A microprocessor to handle all of the logic and arithmetic necessary. By using the microprocessor, future hardware modifications could easily be made if functional changes were needed.

Effect of lullaby and classical music on physiologic stability of hospitalized preterm infants: a randomized trial.

PubMed

Amini, E; Rafiei, P; Zarei, K; Gohari, M; Hamidi, M

2013-01-01

Music is considered a subset of developmental supportive care. It may act as a suitable auditory stimulant in preterm infants. Also, it may reduce stress responses in autonomic, motor and state systems. To assess and compare the influence of lullaby and classical music on physiologic parameters. This is a randomized clinical trial with cross-over design. A total of 25 stable preterm infants with birth weight of 1000-2500 grams were studied for six consecutive days. Each infant was exposed to three phases: lullaby music, classical music, and no music (control) for two days each. The sequence of these phases was assigned randomly to each subject. Babies were continuously monitored for heart rate, respiratory rate, and oxygen saturation and changes between phases were analyzed. Lullaby reduced heart rate (p < 0.001) and respiratory rate (p = 0.004). These effects extended in the period after the exposure (p < .001 and p = 0.001, respectively). Classical music reduced heart rate (p = 0.018). The effects of classical music disappeared once the music stopped. Oxygen saturation did not change during intervention. Music can affect vital signs of preterm infants; this effect can possibly be related to the reduction of stress during hospitalization. The implications of these findings on clinical and developmental outcomes need further study.

The effects of heart rate control in chronic heart failure with reduced ejection fraction.

PubMed

Grande, Dario; Iacoviello, Massimo; Aspromonte, Nadia

2018-07-01

Elevated heart rate has been associated with worse prognosis both in the general population and in patients with heart failure. Heart rate is finely modulated by neurohormonal signals and it reflects the balance between the sympathetic and the parasympathetic limbs of the autonomic nervous system. For this reason, elevated heart rate in heart failure has been considered an epiphenomenon of the sympathetic hyperactivation during heart failure. However, experimental and clinical evidence suggests that high heart rate could have a direct pathogenetic role. Consequently, heart rate might act as a pathophysiological mediator of heart failure as well as a marker of adverse outcome. This hypothesis has been supported by the observation that the positive effect of beta-blockade could be linked to the degree of heart rate reduction. In addition, the selective heart rate control with ivabradine has recently been demonstrated to be beneficial in patients with heart failure and left ventricular systolic dysfunction. The objective of this review is to examine the pathophysiological implications of elevated heart rate in chronic heart failure and explore the mechanisms underlying the effects of pharmacological heart rate control.

Comparison of the anaesthetic efficacy of and heart rate changes after periodontal ligament or intraosseous X-Tip injection in mandibular molars: a randomized controlled clinical trial.

PubMed

Zarei, M; Ghoddusi, J; Sharifi, E; Forghani, M; Afkhami, F; Marouzi, Parviz

2012-10-01

To compare the efficacy of supplemental anaesthesia using periodontal ligament injections (PDL) and intraosseous injections with the X-Tip system in terms of the measured heart rate and patient reported pain level. In this single-blind randomized clinical trial, 40 patients (22 women, 18 men) with irreversible pulpitis who had experienced unsuccessful pain management by inferior alveolar nerve block with 2% lidocaine and 1 : 100 000 epinephrine were selected. Patients were divided equally and randomly into two groups. Supplementary anaesthesia was provided through intraosseous injection with the X-Tip system (X-Tip group) or by PDL injection (PDL group). After each step of injection, pain severity was assessed using a visual analogue scale. Patient heart rate was recorded with a pulse oximeter. Data were coded and analysed using Mann-Whitney U-test with SPSS (version 16) software. Anaesthetic success was obtained in 100% of X-Tip and 70% of PDL group patients after the first supplemental injection. Compared with the first PDL injection, the first intraosseous injection resulted in a significant increase in heart rate (P = 0.001); however, this increase was short-lived (mean increase: 9-10 beats per min). No significant difference in heart rate or anaesthesia success was observed between men and women. Intraosseous injection using the X-Tip system was more effective than PDL injection as a supplementary anaesthetic for pulpectomy in mandibular molars or second premolars. However, the former resulted in a transient increase in heart rate. © 2012 International Endodontic Journal.

A comparison of the cardiovascular effects of simulated and spontaneous laughter.

PubMed

Law, Mikaela M; Broadbent, Elizabeth A; Sollers, John J

2018-04-01

Laughter has long been regarded as beneficial for health, but the mechanisms are not clearly understood. The current study aimed to compare the acute cardiovascular effects of spontaneous and simulated laughter. A mixed factorial experiment was performed to examine changes in cardiovascular variables in response to experimental tasks across conditions. A sample of 72 participants were randomised to one of three 6 min interventions. Participants in the simulated laughter condition were asked to generate fake laughter, the spontaneous laughter condition viewed a humorous video, and the control condition watched a non-humorous documentary. This was followed by a laboratory stress task. Heart rate and heart rate variability (as indexed by rMSSD) were monitored continuously throughout the experiment using ECG. The simulated laughter condition had a significantly higher heart rate (p < .001, η p 2  = .26) and lower rMSSD (p < .001, η p 2  = .13) during the laughter task compared to the other two conditions. Follow-up hierarchical regressions indicated that the difference in heart rate was due to the fact that the simulated condition produced more laughter. The difference in rMSSD, however, was unique to the simulated condition even when controlling for the amount of laughter. The simulated laughter condition had a significantly lower mean HR during the stress task but this was not significant after controlling amount of laughter produced. Laughter leads to increased heart rate and reduced heart rate variability, which is similar to the effects of exercise. This finding is more pronounced in simulated laughter. Copyright © 2018 Elsevier Ltd. All rights reserved.

The relationship between sexual concordance and interoception in anxious and nonanxious women.

PubMed

Suschinsky, Kelly D; Lalumière, Martin L

2014-04-01

Sexual concordance refers to the association between physiological and self-reported sexual arousal. Women typically exhibit lower sexual concordance scores than men. There is also a sex difference in interoception--awareness of (nonsexual) physiological states or responses--such that women, compared with men, tend to be less aware of and less accurate at detecting changes in their physiological responses. Women with anxiety problems tend to have better interoceptive abilities than nonanxious women. To investigate whether women's lower sexual concordance is associated with interoception using a sample likely to show high variation in interoceptive abilities. Sixteen anxious and 15 nonanxious women were presented with twelve 90 seconds sexual and nonsexual film clips while their genital response, heart rate, and respiration rate were measured. A heartbeat mental tracking task was also employed. Genital response was measured with a vaginal photoplethysmograph. Heart rate was measured with an electrocardiogram and respiration rate with a thermistor. Participants estimated their physiological responses after each film. A mental tracking task was also used to assess participants' awareness of heart rate. Within-subject correlations were computed for each physiological/self-reported response combination. Overall, sexual concordance (i.e., the correlation between genital responses and perceptions of genital response) was not significantly associated with heart rate awareness or respiration rate awareness. Anxious women did not exhibit significantly higher sexual concordance or heart rate awareness than nonanxious women; the nonanxious women actually exhibited higher respiration rate awareness. The results suggest that sexual concordance may be a distinct phenomenon from interoception and in need of its own explanation. © 2013 International Society for Sexual Medicine.

Impact of double counting and transfer bias on estimated rates and outcomes of acute myocardial infarction.

PubMed

Westfall, J M; McGloin, J

2001-05-01

Ischemic heart disease is the leading cause of death in the United States. Recent studies report inconsistent findings on the changes in the incidence of hospitalizations for ischemic heart disease. These reports have relied primarily on hospital discharge data. Preliminary data suggest that a significant percentage of patients suffering acute myocardial infarction (MI) in rural communities are transferred to urban centers for care. Patients transferred to a second hospital may be counted twice for one episode of ischemic heart disease. To describe the impact of double counting and transfer bias on the estimation of incidence rates and outcomes of ischemic heart disease, specifically acute MI, in the United States. Analysis of state hospital discharge data from Kansas, Colorado (State Inpatient Database [SID]), Nebraska, Arizona, New Jersey, Michigan, Pennsylvania, and Illinois (SID) for the years 1995 to 1997. A matching algorithm was developed for hospital discharges to determine patients counted twice for one episode of ischemic heart disease. Validation of our matching algorithm. Patients reported to have suffered ischemic heart disease (ICD9 codes 410-414, 786.5). Number of patients counted twice for one episode of acute MI. It is estimated that double count rates range from 10% to 15% for all states and increased over the 3 years. Moderate sized rural counties had the highest estimated double count rates at 15% to 20% with a few counties having estimated double count rates a high as 35% to 50%. Older patients and females were less likely to be double counted (P <0.05). Double counting patients has resulted in a significant overestimation in the incidence rate for hospitalization for acute MI. Correction of this double counting reveals a significantly lower incidence rate and a higher in-hospital mortality rate for acute MI. Transferred patients differ significantly from nontransferred patients, introducing significant bias into MI outcome studies. Double counting and transfer bias should be considered when conducting and interpreting research on ischemic heart disease, particularly in rural regions.

Hydroxychloroquine reduces heart rate by modulating the hyperpolarization-activated current If: Novel electrophysiological insights and therapeutic potential.

PubMed

Capel, Rebecca A; Herring, Neil; Kalla, Manish; Yavari, Arash; Mirams, Gary R; Douglas, Gillian; Bub, Gil; Channon, Keith; Paterson, David J; Terrar, Derek A; Burton, Rebecca-Ann B

2015-10-01

Bradycardic agents are of interest for the treatment of ischemic heart disease and heart failure, as heart rate is an important determinant of myocardial oxygen consumption. The purpose of this study was to investigate the propensity of hydroxychloroquine (HCQ) to cause bradycardia. We assessed the effects of HCQ on (1) cardiac beating rate in vitro (mice); (2) the "funny" current (If) in isolated guinea pig sinoatrial node (SAN) myocytes (1, 3, 10 µM); (3) heart rate and blood pressure in vivo by acute bolus injection (rat, dose range 1-30 mg/kg), (4) blood pressure and ventricular function during feeding (mouse, 100 mg/kg/d for 2 wk, tail cuff plethysmography, anesthetized echocardiography). In mouse atria, spontaneous beating rate was significantly (P < .05) reduced (by 9% ± 3% and 15% ± 2% at 3 and 10 µM HCQ, n = 7). In guinea pig isolated SAN cells, HCQ conferred a significant reduction in spontaneous action potential firing rate (17% ± 6%, 1 μM dose) and a dose-dependent reduction in If (13% ± 3% at 1 µM; 19% ± 2% at 3 µM). Effects were also observed on L-type calcium ion current (ICaL) (12% ± 4% reduction) and rapid delayed rectifier potassium current (IKr) (35% ± 4%) at 3 µM. Intravenous HCQ decreased heart rate in anesthetized rats (14.3% ± 1.1% at 15mg/kg; n = 6) without significantly reducing mean arterial blood pressure. In vivo feeding studies in mice showed no significant change in systolic blood pressure nor left ventricular function. We have shown that HCQ acts as a bradycardic agent in SAN cells, in atrial preparations, and in vivo. HCQ slows the rate of spontaneous action potential firing in the SAN through multichannel inhibition, including that of If. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Effects of HRV-Guided vs. Predetermined Block Training on Performance, HRV and Serum Hormones.

PubMed

Nuuttila, Olli-Pekka; Nikander, Aku; Polomoshnov, Dmitry; Laukkanen, Jari Antero; Häkkinen, Keijo

2017-11-01

The aim of this study was to compare heart rate variability -guided (HRVG) and predetermined (PD) block periodization of high intensity aerobic training (HIT). Endurance performance, neuromuscular performance, heart rate variability (HRV) and serum hormone concentrations were measured before, in the middle and after the 8-week training period in 24 endurance trained males. Both groups improved significantly maximal treadmill velocity (V max ) (p<0.001) and 3000 m running performance (HRVG; p<0.001 and PD; p=0.001). The relative changes in V max and countermovement jump were significantly greater in HRVG (p<0.05). Nocturnal heart rate decreased in both groups (p<0.01), but HRV (RMSSD, LF and TP) increased significantly only in HRVG (p<0.05). The significant increase in serum testosterone concentration was observed from mid to post in HRVG (p<0.05). Significant correlations were found between individual V max changes and absolute serum testosterone levels. Individual baseline level of HF correlated significantly with V max changes in PD. Block periodization of HIT seems to be an effective way to improve endurance and running performance in already endurance trained males. Based on training induced increases in endurance and neuromuscular performance combined with significant changes in HRV and serum testosterone levels observed in HRVG, individually HRV -guided block training may be more optimal compared to predetermined training. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of Heart Rate Variability Biofeedback on EEG Alpha Asymmetry and Anxiety Symptoms in Male Athletes: A Pilot Study.

PubMed

Dziembowska, Inga; Izdebski, Paweł; Rasmus, Anna; Brudny, Janina; Grzelczak, Marta; Cysewski, Piotr

2016-06-01

Heart rate variability biofeedback (HRV-BFB) has been shown as useful tool to manage stress in various populations. The present study was designed to investigate whether the biofeedback-based stress management tool consisting of rhythmic breathing, actively self-generated positive emotions and a portable biofeedback device induce changes in athletes' HRV, EEG patterns, and self-reported anxiety and self-esteem. The study involved 41 healthy male athletes, aged 16-21 (mean 18.34 ± 1.36) years. Participants were randomly divided into two groups: biofeedback and control. Athletes in the biofeedback group received HRV biofeedback training, athletes in the control group didn't receive any intervention. During the randomized controlled trial (days 0-21), the mean anxiety score declined significantly for the intervention group (change-4 p < 0.001) but not for the control group (p = 0.817). In addition, as compared to the control, athletes in biofeedback group showed substantial and statistically significant improvement in heart rate variability indices and changes in power spectra of both theta and alpha brain waves, and alpha asymmetry. These changes suggest better self-control in the central nervous system and better flexibility of the autonomic nervous system in the group that received biofeedback training. A HRV biofeedback-based stress management tool may be beneficial for stress reduction for young male athletes.

Changes in the PQRST intervals and heart rate variability associated with rewarming in two newborns undergoing hypothermia therapy.

PubMed

Lasky, Robert E; Parikh, Nehal A; Williams, Amber L; Padhye, Nikhil S; Shankaran, Seetha

2009-01-01

Little is known about the effects of hypothermia therapy and subsequent rewarming on the PQRST intervals and heart rate variability (HRV) in term newborns with hypoxic-ischemic encephalopathy (HIE). This study describes the changes in the PQRST intervals and HRV during rewarming to normal core body temperature of 2 newborns with HIE after hypothermia therapy. Within 6 h after birth, 2 newborns with HIE were cooled to a core body temperature of 33.5 degrees C for 72 h using a cooling blanket, followed by gradual rewarming (0.5 degrees C per hour) until the body temperature reached 36.5 degrees C. Custom instrumentation recorded the electrocardiogram from the leads used for clinical monitoring of vital signs. Generalized linear mixed models were calculated to estimate temperature-related changes in PQRST intervals and HRV. For every 1 degrees C increase in body temperature, the heart rate increased by 9.2 bpm (95% CI 6.8-11.6), the QTc interval decreased by 21.6 ms (95% CI 17.3-25.9), and low and high frequency HRV decreased by 0.480 dB (95% CI 0.052-0.907) and 0.938 dB (95% CI 0.460-1.416), respectively. Hypothermia-induced changes in the electrocardiogram should be monitored carefully in future studies. Copyright 2009 S. Karger AG, Basel.

[Variability of heart rhythm in dynamic study of the psychovegetative relationship in neurogenic syncope].

PubMed

Musaeva, Z A; Khaspekova, N B; Veĭn, A M

2001-01-01

Physiological changes accompanying syncopes of neural origin (SNO) in patients with psychovegetative syndrome are still insufficiently studied. The data concerning the role of the autonomic nervous system are discrepant. Heart rate variability was analyzed in 68 patients with SNO in a supine position and during the active 20-min orthostatic test taking into account the heart rate components of very low frequency (VLF, an index of cerebral sympathetic activity) and high frequency (HF, a marker of vagal modulation). Steady growth of the VLF and progressive decrease in the LF within 15-20 min of the orthostasis were observed in all the patients (n = 33), who fainted after this period. The predominance of the VLF in the heart rate power spectra was correlated with a high level of anxiety. It is suggested that this fact indicates the stable cerebral sympathetic activation resulting in a baroreceptor dysfunction, i.e., a failure of vasomotor regulation in patients with SNO.

Heart rate variability in the standing position reflects training adaptation in professional soccer players.

PubMed

Ravé, Guillaume; Fortrat, Jacques-Olivier

2016-08-01

To show that heart rate variability (HRV) in the standing position better reflects the way in which athletes adapt to training in so-called intermittent sports than the indicator of resting parasympathetic tone usually employed in endurance sports. Twenty professional soccer players (intermittent sport) took part in a 5-week training session divided into three successive periods: "Warm-up", "Intensive training" and "Tapering". At the beginning and end of each of the three periods, a stand test was carried out and the heart rate was recorded, beat by beat (Polar Team 2). We analysed HRV to determine the indicator mostly used to demonstrate training adaptation in endurance sports (lnRMSSD supine, natural logarithm of root mean square of the successive differences) as well as indicators obtained by means of spectral analysis in both supine and standing position. A decrease in heart rate was observed in the supine position at rest during training (-5.2 ± 1.3 bpm) while lnRMSSD and spectral analysis indicators remained unchanged. The "Warm-up" caused an increase in spectral analysis total power in standing position which was further highlighted by "Tapering" (3.39 ± 0.09, 3.61 ± 0.08 and 3.65 ± 0.09 log ms(2), respectively). However, the autonomic changes are probably more complex than a change in autonomic activity or balance since spectral analysis autonomic indicators remained unchanged. HRV in the standing position could monitor training adaptation in intermittent sports contrary to the indicator usually employed in endurance sports. However, the significance of the HRV change in the standing position during training remains unclear.

Oxytocin treatment does not change cardiovascular parameters, hematology and plasma electrolytes in parturient horse mares.

PubMed

Nagel, Christina; Trenk, Lisa; Wulf, Manuela; Ille, Natascha; Aurich, Jörg; Aurich, Christine

2017-03-15

In mares, foaling is associated with changes in hematology, plasma electrolytes, blood pressure and heart rate and it has been hypothesized that these are induced by oxytocin. To test this hypothesis, mares (n = 8-14/group) were treated with oxytocin (OT; 20 I.U.) or saline (CON) at 1 h (test A) and 12 h after foaling (test B) and during first postpartum diestrus (test C). Heart rate, heart rate variability (HRV), atrioventricular blocks, salivary cortisol concentration, blood pressure, plasma electrolytes and blood count were determined. Heart rate decreased from test A to C (P < 0.001) but at no time differed between groups. The HRV, blood pressure and occurrence of atrioventricular blocks did not change in response to oxytocin. Cortisol concentration decreased from test A to C (P < 0.001). Oxytocin induced a cortisol release in test B (time x treatment P < 0.001, time x test P < 0.001). Plasma sodium and chloride concentrations decreased from test A to C (P < 0.001) but did not differ between groups. In test A, potassium concentration increased in CON but not OT mares (time P < 0.01, time x test P < 0.01, time x treatment P < 0.05). Polymorphnuclear cell (PMN) numbers in blood decreased from test A to C (P < 0.001) while lymphocytes increased (P < 0.05). At no time PMN and lymphocytes differed between groups. Oxytocin treatment had no effect on skin temperature. In conclusion, except for a limited effect on cortisol release, oxytocin was without effect and the hypothesis of oxytocin-induced alterations in cardiac parameters, plasma electrolytes and hematology of foaling mares was not verified. Copyright © 2016 Elsevier Inc. All rights reserved.

Correlation between skin temperature and heart rate during exercise and recovery, and the influence of body position in these variables in untrained women

NASA Astrophysics Data System (ADS)

Neves, Eduardo Borba; Cunha, Raphael Martins; Rosa, Claudio; Antunes, Natacha Sousa; Felisberto, Ivo Miguel Vieira; Vilaça-Alves, José; Reis, Victor Machado

2016-03-01

It was known that the thermal response varies according to some variables. Until now, there are no studies that have investigated the relationship of skin temperature and heart rate during and after the workout, either the thermal behavior during postural changes. Objective: the aim of this study was to evaluate the behavior of skin temperature and heart rate, during exercise and up to an hour of recovery (with postural change), performed in two different intensities sessions (70% and 85% of 10 repetitions maximum) and observe the correlation between them. Method: This was a short longitudinal study, carried out with women aged from 18 to 30 years. A sample of 31 untrained women, aged 18 and 30 was used. The volunteers were randomized into two groups: Biceps Group (BG), with 15 women, and Quadriceps Group (QG) with 16 women. Results: During and after completion of the exercise session, there was a significant reduction in skin temperature on the active muscles in both groups (BG and QG), with similar thermal responses for the two intensities studied (70% and 85%) to the minute 15 (which marks the end of the recovery in the standing position). From minute 15 to minute 20-60, the skin temperature increases abruptly and significantly, returning to levels close to those observed before exercise. Conclusion: There were no statistical differences in thermal response to exercises in 70% or 85% of 10RM. There is a negative correlation between heart rate and skin temperature when untrained women perform anaerobic exercise. It was observed that after a change of posture (from a standing position to a sitting posture) skin temperature increased abruptly and significantly.

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.

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, Robert A., III (Inventor)

1994-01-01

An apparatus for acquiring signals emitted by a fetus, identifying fetal heart beats and determining a fetal heart rate is presented. 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.

Aging and CaMKII Alter Intracellular Ca2+ Transients and Heart Rhythm in Drosophila melanogaster

PubMed Central

Santalla, Manuela; Valverde, Carlos A.; Harnichar, Ezequiel; Lacunza, Ezequiel; Aguilar-Fuentes, Javier; Mattiazzi, Alicia; Ferrero, Paola

2014-01-01

Aging is associated to disrupted contractility and rhythmicity, among other cardiovascular alterations. Drosophila melanogaster shows a pattern of aging similar to human beings and recapitulates the arrhythmogenic conditions found in the human heart. Moreover, the kinase CaMKII has been characterized as an important regulator of heart function and an arrhythmogenic molecule that participate in Ca2+ handling. Using a genetically engineered expressed Ca2+ indicator, we report changes in cardiac Ca2+ handling at two different ages. Aging prolonged relaxation, reduced spontaneous heart rate (HR) and increased the occurrence of arrhythmias, ectopic beats and asystoles. Alignment between Drosophila melanogaster and human CaMKII showed a high degree of conservation and indicates that relevant phosphorylation sites in humans are also present in the fruit fly. Inhibition of CaMKII by KN-93 (CaMKII-specific inhibitor), reduced HR without significant changes in other parameters. By contrast, overexpression of CaMKII increased HR and reduced arrhythmias. Moreover, it increased fluorescence amplitude, maximal rate of rise of fluorescence and reduced time to peak fluorescence. These results suggest that CaMKII in Drosophila melanogaster acts directly on heart function and that increasing CaMKII expression levels could be beneficial to improve contractility. PMID:25003749

Cardiovascular adaptation to extrauterine life after intrauterine growth restriction.

PubMed

Rodriguez-Guerineau, Luciana; Perez-Cruz, Miriam; Gomez Roig, María D; Cambra, Francisco J; Carretero, Juan; Prada, Fredy; Gómez, Olga; Crispi, Fátima; Bartrons, Joaquim

2018-02-01

Introduction The adaptive changes of the foetal heart in intrauterine growth restriction can persist postnatally. Data regarding its consequences for early circulatory adaptation to extrauterine life are scarce. The aim of this study was to assess cardiac morphometry and function in newborns with late-onset intrauterine growth restriction to test the hypothesis that intrauterine growth restriction causes cardiac shape and functional changes at birth. A comprehensive echocardiographic study was performed in 25 neonates with intrauterine growth restriction and 25 adequate-for-gestational-age neonates. Compared with controls, neonates with intrauterine growth restriction had more globular ventricles, lower longitudinal tricuspid annular motion, and higher left stroke volume without differences in the heart rate. Neonates with intrauterine growth restriction also showed subclinical signs of diastolic dysfunction in the tissue Doppler imaging with lower values of early (e') diastolic annular peak velocities in the septal annulus. Finally, the Tei index in the tricuspid annulus was higher in the intrauterine growth restriction group. Neonates with history of intrauterine growth restriction showed cardiac remodelling and signs of systolic and diastolic dysfunction. Overall, there was a significant tendency to worse cardiac function results in the right heart. The adaptation to extrauterine life occurred with more globular hearts, higher stroke volumes but a similar heart rate compared to adequate-for-gestational-age neonates.

A novel method to estimate changes in stress-induced salivary α-amylase using heart rate variability and respiratory rate, as measured in a non-contact manner using a single radar attached to the back of a chair.

PubMed

Matsui, Takemi; Katayose, Satoshi

2014-08-01

The authors have developed a non-contact system which estimates changes in salivary α-amylase (sAA ratio) induced by stress. Before and after stressful sound exposure, a single 24 GHz compact radar which is attached to the back of a chair measures the low frequency (LF) component of heart rate variability and respiratory rate, α-amylase in the subjects' buccal secretions was measured by using an α-amylase assay kit. Using multiple regression analysis, sAA ratio was estimated using stress-induced LF change (LF ratio) and stress-induced respiratory rate change (respiratory rate ratio). Twelve healthy subjects were tested (12 males, 22 ± 2 years), who were exposed to audio stimuli with a composite tone of 2120 Hz and 2130 Hz sine waves at a sound pressure level of 95 dB after a silent period through a headphone. The result showed that sAA ratio estimated using multiple regression analysis significantly correlated with measured sAA ratio (R = 0.76, p < 0.01). This indicates that the system may serve for a stress management in the future.

Video-based heart rate monitoring across a range of skin pigmentations during an acute hypoxic challenge.

PubMed

Addison, Paul S; Jacquel, Dominique; Foo, David M H; Borg, Ulf R

2017-11-09

The robust monitoring of heart rate from the video-photoplethysmogram (video-PPG) during challenging conditions requires new analysis techniques. The work reported here extends current research in this area by applying a motion tolerant algorithm to extract high quality video-PPGs from a cohort of subjects undergoing marked heart rate changes during a hypoxic challenge, and exhibiting a full range of skin pigmentation types. High uptimes in reported video-based heart rate (HR vid ) were targeted, while retaining high accuracy in the results. Ten healthy volunteers were studied during a double desaturation hypoxic challenge. Video-PPGs were generated from the acquired video image stream and processed to generate heart rate. HR vid was compared to the pulse rate posted by a reference pulse oximeter device (HR p ). Agreement between video-based heart rate and that provided by the pulse oximeter was as follows: Bias = - 0.21 bpm, RMSD = 2.15 bpm, least squares fit gradient = 1.00 (Pearson R = 0.99, p < 0.0001), with a 98.78% reporting uptime. The difference between the HR vid and HR p exceeded 5 and 10 bpm, for 3.59 and 0.35% of the reporting time respectively, and at no point did these differences exceed 25 bpm. Excellent agreement was found between the HR vid and HR p in a study covering the whole range of skin pigmentation types (Fitzpatrick scales I-VI), using standard room lighting and with moderate subject motion. Although promising, further work should include a larger cohort with multiple subjects per Fitzpatrick class combined with a more rigorous motion and lighting protocol.

Aerobic Stimulus Induced by Virtual Reality Games in Stroke Survivors.

PubMed

Silva de Sousa, Julio Cesar; Torriani-Pasin, Camila; Tosi, Amanda Barboza; Fecchio, Rafael Yokoyama; Costa, Luiz Augusto Riani; Forjaz, Cláudia Lúcia de Moraes

2018-05-01

To evaluate whether virtual reality games (VRGs) in stroke survivors produce significant and reproducible heart rate and oxygen consumption (V˙o 2 ) responses during their execution, corresponding to an intensity between the anaerobic threshold (AT) and the respiratory compensation point (RCP). Single-subject, repeated-measure design. Stroke survivors registered from a rehabilitation program. Chronic hemiparetic stroke survivors (N=12; 10 men; mean age ± SD, 58±12y) rated at 3 or 4 in the Functional Ambulation Categories. Participants underwent, in a random order, 2 identical sessions of VRGs (console Xbox 360 + Kinect) and 1 control session (38min watching a movie). The VRG sessions were composed of 4 sets of VRGs (3min of tennis, 1min for changing the game, and 4min of boxing) interspaced with 2 minutes of rest. Heart rate and V˙o 2 were measured during the experimental sessions and compared with heart rate and V˙o 2 obtained at AT and RCP assessed during a maximal cardiopulmonary exercise test. Heart rate and V˙o 2 during VRGs had good reproducibility (intraclass correlation coefficients, ≥.91 and ≥.85, respectively; coefficients of variation, ≤6.7% and ≤13.7%, respectively). Heart rate during VRGs was similar to AT and significantly lower than RCP (P≤.05), while V˙o 2 was significantly lower than AT and RCP (P<.05). An acute session of VRGs composed of tennis and boxing games using the console XBox 360 + Kinect promotes reproducible responses of heart rate and V˙o 2 that corresponded, respectively, to AT and below AT, characterizing a low-intensity aerobic stimulus. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Functional requirements of a mathematical model of the heart.

PubMed

Palladino, Joseph L; Noordergraaf, Abraham

2009-01-01

Functional descriptions of the heart, especially the left ventricle, are often based on the measured variables pressure and ventricular outflow, embodied as a time-varying elastance. The fundamental difficulty of describing the mechanical properties of the heart with a time-varying elastance function that is set a priori is described. As an alternative, a new functional model of the heart is presented, which characterizes the ventricle's contractile state with parameters, rather than variables. Each chamber is treated as a pressure generator that is time and volume dependent. The heart's complex dynamics develop from a single equation based on the formation and relaxation of crossbridge bonds. This equation permits the calculation of ventricular elastance via E(v) = partial differentialp(v)/ partial differentialV(v). This heart model is defined independently from load properties, and ventricular elastance is dynamic and reflects changing numbers of crossbridge bonds. In this paper, the functionality of this new heart model is presented via computed work loops that demonstrate the Frank-Starling mechanism and the effects of preload, the effects of afterload, inotropic changes, and varied heart rate, as well as the interdependence of these effects. Results suggest the origin of the equivalent of Hill's force-velocity relation in the ventricle.

Benefits of belonging: experimental manipulation of social inclusion to enhance psychological and physiological health parameters.

PubMed

Begen, Fiona M; Turner-Cobb, Julie M

2015-01-01

Acute changes in social belonging are important triggers for alterations in health and well-being, yet research has emphasised the negative effects of 'exclusion' at the expense of evaluating the potentially positive effects of 'inclusion'. This study examined the impact of acute belonging on physiological and psychological outcomes. A healthy population (N = 138) were randomly allocated to 'included' or 'excluded' conditions. Condition-dependent differences in pre/during-task heart rate and pre/post-task self-reports of negative/positive mood, and social self-esteem, were assessed. Included participants showed decreased heart rate and negative mood, and increased social self-esteem. No inclusion-related change in positive mood was shown. An increase in heart rate was observed in excluded participants though no changes in negative/positive mood or social self-esteem were shown. Shifts in social self-esteem acted as a mechanism through which inclusion/exclusion impacted upon negative and positive mood alterations. Results remained significant in presence of covariates (sex, global self-esteem, rumination and social anxiety). Findings suggest that acting to enhance belonging through 'inclusion' resulted in adaptive physiological and psychological outcomes. Neutral and potentially protective responses were observed in the immediate aftermath of 'exclusion'. Self-esteem served as one route through which these effects were transmitted.

Baroreflex modulation of sympathetic nerve activity to muscle in heat-stressed humans

NASA Technical Reports Server (NTRS)

Cui, Jian; Wilson, Thad E.; Crandall, Craig G.

2002-01-01

To identify whether whole body heating alters arterial baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA and beat-by-beat arterial blood pressure were recorded in seven healthy subjects during acute hypotensive and hypertensive stimuli in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature (P < 0.01), MSNA (P < 0.01), heart rate (P < 0.01), and skin blood flow (P < 0.001), whereas mean arterial blood pressure did not change significantly (P > 0.05). During both normothermic and heat stress conditions, MSNA increased and then decreased significantly when blood pressure was lowered and then raised via intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure during heat stress (-128.3 +/- 13.9 U x beats(-1) x mmHg(-1)) was similar (P = 0.31) with normothermia (-140.6 +/- 21.1 U x beats(-1) x mmHg(-1)). Moreover, no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that arterial baroreflex modulation of MSNA and heart rate are not altered by whole body heating, with the exception of an upward shift of these baroreflex curves to accommodate changes in these variables that occur with whole body heating.

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.

Xinyinqin: a computer-based heart sound simulator.

PubMed

Zhan, X X; Pei, J H; Xiao, Y H

1995-01-01

"Xinyinqin" is the Chinese phoneticized name of the Heart Sound Simulator (HSS). The "qin" in "Xinyinqin" is the Chinese name of a category of musical instruments, which means that the operation of HSS is very convenient--like playing an electric piano with the keys. HSS is connected to the GAME I/O of an Apple microcomputer. The generation of sound is controlled by a program. Xinyinqin is used as a teaching aid of Diagnostics. It has been applied in teaching for three years. In this demonstration we will introduce the following functions of HSS: 1) The main program has two modules. The first one is the heart auscultation training module. HSS can output a heart sound selected by the student. Another program module is used to test the student's learning condition. The computer can randomly simulate a certain heart sound and ask the student to name it. The computer gives the student's answer an assessment: "correct" or "incorrect." When the answer is incorrect, the computer will output that heart sound again for the student to listen to; this process is repeated until she correctly identifies it. 2) The program is convenient to use and easy to control. By pressing the S key, it is able to output a slow heart rate until the student can clearly identify the rhythm. The heart rate, like the actual rate of a patient, can then be restored by hitting any key. By pressing the SPACE BAR, the heart sound output can be stopped to allow the teacher to explain something to the student. The teacher can resume playing the heart sound again by hitting any key; she can also change the content of the training by hitting RETURN key. In the future, we plan to simulate more heart sounds and incorporate relevant graphs.

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

State-of-the-art implantable cardiac assist device therapy for heart failure: bridge to transplant and destination therapy.

PubMed

Park, S J; Kushwaha, S S; McGregor, C G A

2012-01-01

Congestive heart failure is associated with poor quality of life (QoL) and low survival rates. The development of state-of-the-art cardiac devices holds promise for improved therapy in patients with heart failure. The field of implantable cardiac assist devices is changing rapidly with the emergence of continuous-flow pumps (CFPs). The important developments in this field, including pertinent clinical trials, registry reports, innovative research, and potential future directions are discussed in this paper.

Circulatory response and autonomic nervous activity during gum chewing.

PubMed

Hasegawa, Yoko; Sakagami, Joe; Ono, Takahiro; Hori, Kazuhiro; Zhang, Min; Maeda, Yoshinobu

2009-08-01

Mastication has been proven to enhance the systemic circulation, with circulatory responses seeming to be largely regulated by autonomic nervous activity via a more complex regulatory system than those of other activities. However, few studies have examined the relationships between changes in autonomic nervous activity and the systemic circulation that are induced by masticatory movement. We investigated changes in the systemic circulation and autonomic nervous activity during gum chewing to clarify the influence of mastication. Electrocardiograms, arterial blood pressure, and masseter electromyograms were taken while chewing gum continuously as indicators of systemic circulation in 10 healthy subjects with normal dentition. Cardiac sympathetic activity and vagus nervous activity, as well as vasomotor sympathetic nervous activity, were evaluated by fluctuation analysis of heart rate and blood pressure. Repeated analysis of variance and multiple comparisons were performed to determine chronological changes in each indicator during gum chewing. Gum chewing increased the heart rate and the mean arterial pressure. Although cardiac sympathetic activity and vagus nervous activity showed significant changes, vasomotor sympathetic nervous activity did not. These results suggest that changes in the autonomic nervous activity of the heart are mainly involved in the enhancement of systemic circulation with gum chewing. This explains some characteristics of autonomic nervous regulation in masticatory movement.

Whole body heat stress attenuates the pressure response to muscle metaboreceptor stimulation in humans.

PubMed

Cui, Jian; Blaha, Cheryl; Sinoway, Lawrence I

2016-11-01

The effects of whole body heat stress on sympathetic and cardiovascular responses to stimulation of muscle metaboreceptors and mechanoreceptors remains unclear. We examined the muscle sympathetic nerve activity (MSNA), blood pressure, and heart rate in 14 young healthy subjects during fatiguing isometric handgrip exercise, postexercise circulatory occlusion (PECO), and passive muscle stretch during PECO. The protocol was performed under normothermic and whole body heat stress (increase internal temperature ~0.6°C via a heating suit) conditions. Heat stress increased the resting MSNA and heart rate. Heat stress did not alter the mean blood pressure (MAP), heart rate, and MSNA responses (i.e., changes) to fatiguing exercise. During PECO, whole body heat stress accentuated the heart rate response [change (Δ) of 5.8 ± 1.5 to Δ10.0 ± 2.1 beats/min, P = 0.03], did not alter the MSNA response (Δ16.4 ± 2.8 to Δ17.3 ± 3.8 bursts/min, P = 0.74), and lowered the MAP response (Δ20 ± 2 to Δ12 ± 1 mmHg, P < 0.001). Under normothermic conditions, passive stretch during PECO evoked significant increases in MAP and MSNA (both P < 0.001). Of note, heat stress prevented the MAP and MSNA responses to stretch during PECO (both P > 0.05). These data suggest that whole body heat stress attenuates the pressor response due to metaboreceptor stimulation, and the sympathetic nerve response due to mechanoreceptor stimulation. Copyright © 2016 the American Physiological Society.

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…

The effects of occupational noise on blood pressure and heart rate of workers in an automotive parts industry

PubMed Central

Kalantary, Saba; Dehghani, Ali; Yekaninejad, Mir Saeed; Omidi, Leila; Rahimzadeh, Mitra

2015-01-01

BACKGROUND One of the most important impacts of industrial noise is physiological and psychological effects. The increases in workers’ blood pressure and heart rate were detected during and after exposure to high levels of noise. The objectives of this research were to determine whether the noise exposures have any effects on blood pressure and heart rate of workers in the automotive parts industry. METHODS This case study was done in 2011 at different units of an automotive parts manufacturing in Tehran. Sound pressure level was measured at different units of the factory with a calibrated instrument. Demographic features of workers were gathered with an appropriate questionnaire. Heart rate and blood pressure were measured twice in a day in the start time of work day (before exposure to noise) and middle shift hours (during exposure to noise) in the occupational physician office. For analyzing data, chi-square, independent sample t-test, paired t-test, and analysis of covariance (ANCOVA) were used. P < 0.050 was considered statistically significant. RESULTS The average age of workers in the case and control groups was 35.71 ± 8.10 and 33.40 ± 10.41 years, respectively. There was no difference between the average age of case and control groups (P = 0.436). The results of ANCOVA revealed the significant differences between the mean changes of heart rate F (1, 37) = 26.68, P < 0.001, systolic blood pressure F (1, 37) = 21.70, P < 0.001, and diastolic blood pressure F (1, 37) = 26.20, P < 0.001 of workers in the case and control groups. CONCLUSION Exposure to industrial noise may increase the heart rate of workers. Although rises in heart rate, systolic, and diastolic blood pressure of workers in the case group were observed after exposure to noise, the values of heart rate, systolic, and diastolic blood pressure were in the normal range. Further experimental investigations are needed to determine the relationships between these variables. PMID:26478728

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. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Work Physiology Evaluation of Laundry Workers

NASA Astrophysics Data System (ADS)

Sari, A. D.; Suryoputro, M. R.; Pramaningtyas, M. D.; Putra, P. S.; Maulidyawati, S. B.

2016-01-01

This study aimed to assess cardiovascular strain during laundry operations in terms of physical workload, based on heart rate changes and level of pain complaints. Researchers measured resting and working heart rates and calculated cardiovascular load (%CVL), cardiovascular strain (%CVS), reserve heart rate (%RHR), energy expenditure, oxygen consumption, and measure level of pain complain in 6 laundry workers using Nordic Body Map questionnaire (NBM). Based on the result of %CVL and %CVS, the work in laundry was classified as acceptable level. Similarly, a high-level category was recorded for %RHR in moderate of energy expenditure. However, there are very pain level complain for hand using NBM questionnaire. Thus, there is a need to redesign the work content of equipment used and keep the physical workload in acceptable level, as this will increase their productivity and reduce their health risk.

Estimation of Circadian Body Temperature Rhythm Based on Heart Rate in Healthy, Ambulatory Subjects.

PubMed

Sim, Soo Young; Joo, Kwang Min; Kim, Han Byul; Jang, Seungjin; Kim, Beomoh; Hong, Seungbum; Kim, Sungwan; Park, Kwang Suk

2017-03-01

Core body temperature is a reliable marker for circadian rhythm. As characteristics of the circadian body temperature rhythm change during diverse health problems, such as sleep disorder and depression, body temperature monitoring is often used in clinical diagnosis and treatment. However, the use of current thermometers in circadian rhythm monitoring is impractical in daily life. As heart rate is a physiological signal relevant to thermoregulation, we investigated the feasibility of heart rate monitoring in estimating circadian body temperature rhythm. Various heart rate parameters and core body temperature were simultaneously acquired in 21 healthy, ambulatory subjects during their routine life. The performance of regression analysis and the extended Kalman filter on daily body temperature and circadian indicator (mesor, amplitude, and acrophase) estimation were evaluated. For daily body temperature estimation, mean R-R interval (RRI), mean heart rate (MHR), or normalized MHR provided a mean root mean square error of approximately 0.40 °C in both techniques. The mesor estimation regression analysis showed better performance than the extended Kalman filter. However, the extended Kalman filter, combined with RRI or MHR, provided better accuracy in terms of amplitude and acrophase estimation. We suggest that this noninvasive and convenient method for estimating the circadian body temperature rhythm could reduce discomfort during body temperature monitoring in daily life. This, in turn, could facilitate more clinical studies based on circadian body temperature rhythm.

A dual-input nonlinear system analysis of autonomic modulation of heart rate

NASA Technical Reports Server (NTRS)

Chon, K. H.; Mullen, T. J.; Cohen, R. J.

1996-01-01

Linear analyses of fluctuations in heart rate and other hemodynamic variables have been used to elucidate cardiovascular regulatory mechanisms. The role of nonlinear contributions to fluctuations in hemodynamic variables has not been fully explored. This paper presents a nonlinear system analysis of the effect of fluctuations in instantaneous lung volume (ILV) and arterial blood pressure (ABP) on heart rate (HR) fluctuations. To successfully employ a nonlinear analysis based on the Laguerre expansion technique (LET), we introduce an efficient procedure for broadening the spectral content of the ILV and ABP inputs to the model by adding white noise. Results from computer simulations demonstrate the effectiveness of broadening the spectral band of input signals to obtain consistent and stable kernel estimates with the use of the LET. Without broadening the band of the ILV and ABP inputs, the LET did not provide stable kernel estimates. Moreover, we extend the LET to the case of multiple inputs in order to accommodate the analysis of the combined effect of ILV and ABP effect on heart rate. Analyzes of data based on the second-order Volterra-Wiener model reveal an important contribution of the second-order kernels to the description of the effect of lung volume and arterial blood pressure on heart rate. Furthermore, physiological effects of the autonomic blocking agents propranolol and atropine on changes in the first- and second-order kernels are also discussed.

Modest weight loss in moderately overweight postmenopausal women improves heart rate variability.

PubMed

Mouridsen, Mette Rauhe; Bendsen, Nathalie Tommerup; Astrup, Arne; Haugaard, Steen Bendix; Binici, Zeynep; Sajadieh, Ahmad

2013-08-01

To evaluate the effects of weight loss on heart rate (HR) and heart rate variability (HRV) parameters in overweight postmenopausal women. Forty-nine overweight postmenopausal women with an average body mass index of 28.8 ± 1.9 kg/m(2) underwent a 12-week dietary weight-loss programme. Accepted variables for characterization of HRV were analysed before and after the weight loss by 24-h ambulatory ECG monitoring; mean and standard deviation for the time between normal-to-normal complexes (MeanNN and SDNN, respectively), and the mean of standard deviations of normal-to-normal intervals for each 5-min period (SDNNindex). Baseline body fat mass (FM%) and changes in body composition was determined by dual X-ray absorptiometry. Before and after the weight-loss period, total abdominal fat, intra-abdominal fat (IAAT), and subcutaneous abdominal fat (SCAT) were measured by single-slice MRI at L3. The weight loss of 3.9 ± 2.0 kg was accompanied by an improvement of HRV. SDNN increased by 9.2% (p = 0.003) and SDNNindex increased by 11.4% (p = 0.0003). MeanNN increased by 2.4%, reflecting a decrease in mean heart rate from 74.1 to 72.3 beats/min (p = 0.033). Systolic blood pressure (SBP) decreased by 2.7%, total cholesterol by 5.1% and high-sensitivity C-reactive protein (hsCRP) by 15.8% (p = 0.002). Improvements in SDNN and cholesterol were correlated with weight loss (r = -0.329, p = 0.024 and r = 0.327, p = 0.020, respectively) but changes in HR, SBP, and hsCRP were not. IAAT and the IAAT/SCAT-ratio were found to be negatively associated with HRV parameters but changes in body composition were not associated with changes in HRV. The observed improvement of HRV seems to be facilitated by weight loss. IAAT and the IAAT/SCAT ratio were found to be associated with low HRV.

Expression of emotions and physiological changes during teaching

NASA Astrophysics Data System (ADS)

Tobin, Kenneth; King, Donna; Henderson, Senka; Bellocchi, Alberto; Ritchie, Stephen M.

2016-09-01

We investigated the expression of emotions while teaching in relation to a teacher's physiological changes. We used polyvagal theory (PVT) to frame the study of teaching in a teacher education program. Donna, a teacher-researcher, experienced high levels of stress and anxiety prior to beginning to teach and throughout the lesson we used her expressed emotions as a focus for this research. We adopted event-oriented inquiry in a study of heart rate, oxygenation of the blood, and expressed emotions. Five events were identified for multilevel analysis in which we used narrative, prosodic analysis, and hermeneutic-phenomenological methods to learn more about the expression of emotions when Donna had: high heart rate (before and while teaching); low blood oxygenation (before and while teaching); and high blood oxygenation (while teaching). What we learned was consistent with the body's monitoring system recognizing social harm and switching to the control of the unmyelinated vagus nerve, thereby shutting down organs and muscles associated with social communication—leading to irregularities in prosody and expression of emotion. In events involving high heart rate and low blood oxygenation the physiological environment was associated with less effective and sometimes confusing patterns in prosody, including intonation, pace of speaking, and pausing. In a low blood oxygenation environment there was evidence of rapid speech and shallow, irregular breathing. In contrast, during an event in which 100 % blood oxygenation occurred, prosody was perceived to be conducive to engagement and teacher expressed positive emotions, such as satisfaction, while teaching. Becoming aware of the purposes of the research and the results we obtained provided the teacher with tools to enact changes to her teaching practice, especially prosody of the voice. We regard it as a high priority to create tools to allow teachers and students, if and as necessary, to ameliorate excess emotions, and change heart rate, oxygenation levels, and breathing patterns.

Temperature relations of aerial and aquatic physiological performance in a mid-intertidal limpet Cellana toreuma: adaptation to rapid changes in thermal stress during emersion.

PubMed

Huang, Xiongwei; Wang, Tifeng; Ye, Ziwen; Han, Guodong; Dong, Yunwei

2015-01-01

The physiological performance of a mid-intertidal limpet Cellana toreuma was determined to study the physiological adaptation of intertidal animals to rapid changes and extreme temperatures during emersion. The relationship between the Arrhenius breakpoint temperature (ABT) and in situ operative body temperature was studied to predict the possible impact of climate change on the species. The temperature coefficient (Q10) of emersed animals was higher than that of submersed animals and the ratio of aerial: aquatic heart rate rose with increasing temperature. The ABTs of submersed and emersed animals were 30.2 and 34.2°C, respectively. The heart rate and levels of molecular biomarkers (hsps, ampkα, ampkβ and sirt1 mRNA) were determined in 48 h simulated semi-diurnal tides. There were no obvious changes of heart rate and gene expression during the transition between emersion and submersion at room temperature, although expressions of hsp70 and hsp90 were induced significantly after thermal stress. These results indicate that C. toreuma can effectively utilize atmospheric oxygen, and the higher Q10 and ABT of emersed animals are adaptations to the rapid change and extreme thermal stress during emersion. However, the in situ operative body temperature frequently exceeds the aerial ABT of C. toreuma, indicating the occurrence of large-scale mortality of C. toreuma in summer, and this species should be sensitive to increasing temperature in the scenario of climate change. © 2014 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

Cardiac Responses to Thermal, Physical, and Emotional Stress

PubMed Central

Taggart, Peter; Parkinson, Peter; Carruthers, Malcolm

1972-01-01

We have studied the effect of a short period of exposure to the intense heat of a sauna bath on the electrocardiogram and plasma catecholamine, free fatty acid, and triglyceride concentrations in 17 subjects with apparently normal hearts and 18 persons with coronary heart disease. Similar observations were made on 11 of the 17 normal subjects and on 7 of the persons with coronary heart disease in response to exercise. Exposure to heat was associated with an increase in plasma adrenaline with no change in noradrenaline, free fatty acid, or triglyceride concentrations. Exercise was associated with the expected increase in both plasma noradrenaline and adrenaline concentrations. A heart rate up to 180 beats/min was observed in response to both heat and exercise. Apart from the ST-T changes inherent to sinus tachycardia, ST-T segment abnormalities were frequent in response to heat in both the subjects with normal and abnormal hearts, but little change occurred in the ST-T configuration when the subjects were exercised to produce comparable heart rates. Ectopic beats, sometimes numerous and multifocal, were observed in some subjects of both groups in response to heat, but not to exercise. It seems likely that the net unbalanced adrenaline component of the increased plasma catecholamine concentrations (which is also seen in certain emotional stress situations) is predominantly responsible for ischaemic-like manifestations of the electrocardiogram in susceptible subjects. The observations provide further validation for previously reported studies that it is the increased plasma noradrenaline in response to emotional stress that is associated with the release of free fatty acids and ultimate hypertriglyceridaemia, of probable importance in the aetiology of atheroma. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5FIG. 6 PMID:4114377

[Voluntary alpha-power increasing training impact on the heart rate variability].

PubMed

Bazanova, O M; Balioz, N V; Muravleva, K B; Skoraia, M V

2013-01-01

In order to study the effect of the alpha EEG power increasing training at heart rate variability (HRV) as the index of the autonomic regulation of cognitive functions there were follow tasks: (1) to figure out the impact of biofeedback in the voluntary increasing the power in the individual high-frequency alpha-band effect on heart rate variability and related characteristics of cognitive and emotional spheres, (2) to determine the nature of the relationship between alpha activity indices and heart rate variability, depending on the alpha-frequency EEG pattern at rest (3) to examine how the individual alpha frequency EEG pattern is reflected in changes HRV as a result of biofeedback training. Psychometric indicators of cognitive performance, the characteristics of the alpha-EEG activity and heart rate variability (HRV) as LF/HF and pNN50 were recorded in 27 healthy men aged 18-34 years, before, during, and after 10 sessions of training of voluntary increase in alpha power in the individual high-frequency alpha band with eyes closed. To determine the biofeedback effect on the alpha power increasing training, data subjects are compared in 2 groups: experimental (14) with the real and the control group (13 people)--with mock biofeedback. The follow up effect of trainings was studied through month over the 10 training sessions. Results showed that alpha biofeedback training enhanced the fluency and accuracy in cognitive performance, decreased anxiety and frontal EMG, increased resting frequency, width and power in individual upper alpha range only in participants with low baseline alpha frequency. While mock biofeedback increased resting alpha power only in participants with high baseline resting alpha frequency and did change neither cognitive performance, nor HRV indices. Biofeedback training eliminated the alpha power decrease in response to arithmetic task in both with high and low alpha frequency participants and this effect was followed up over the month. Mock biofeedback training has no such effect. The positive correlation between the alpha-peak frequency and pNN50 in patients with initially low, but negative--those with high baseline alpha frequency explains the multidirectional biofeedback effects on HRV in low and high alpha frequency subjects. The individual alpha-frequency EEG pattern determines the effectiveness of the alpha EEG biofeedback training in changing heart rate variability, which provides a basis for predicting the results and develop individual approaches to the biofeedback technology implementation that can be used in clinical practice for treatment and rehabilitation of psychosomatic syndromes and in educational training.

Feasibility and safety of adenosine cardiovascular magnetic resonance in patients with MR conditional pacemaker systems at 1.5 Tesla.

PubMed

Klein-Wiele, Oliver; Garmer, Marietta; Urbien, Rhyan; Busch, Martin; Kara, Kaffer; Mateiescu, Serban; Grönemeyer, Dietrich; Schulte-Hermes, Michael; Garbrecht, Marc; Hailer, Birgit

2015-12-22

Cardiovascular Magnetic Resonance (CMR) with adenosine stress is a valuable diagnostic tool in coronary artery disease (CAD). However, despite the development of MR conditional pacemakers CMR is not yet established in clinical routine for pacemaker patients with known or suspected CAD. A possible reason is that adenosine stress perfusion for ischemia detection in CMR has not been studied in patients with cardiac conduction disease requiring pacemaker therapy. Other than under resting conditions it is unclear whether MR safe pacing modes (paused pacing or asynchronous mode) can be applied safely because the effect of adenosine on heart rate is not precisely known in this entity of patients. We investigate for the first time feasibility and safety of adenosine stress CMR in pacemaker patients in clinical routine and evaluate a pacing protocol that considers heart rate changes under adenosine. We retrospectively analyzed CMR scans of 24 consecutive patients with MR conditional pacemakers (mean age 72.1 ± 11.0 years) who underwent CMR in clinical routine for the evaluation of known or suspected CAD. MR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement. Pacemaker indications were sinus node dysfunction (n = 18) and second or third degree AV block (n = 6). Under a pacing protocol intended to avoid competitive pacing on the one hand and bradycardia due to AV block on the other no arrhythmia occurred. Pacemaker stimulation was paused to prevent competitive pacing in sinus node dysfunction with resting heart rate >45 bpm. Sympatho-excitatory effect of adenosine led to a significant acceleration of heart rate by 12.3 ± 8.3 bpm (p < 0.001), no bradycardia occurred. On the contrary in AV block heart rate remained constant; asynchronous pacing above resting heart rate did not interfere with intrinsic rhythm. Adenosine stress CMR appears to be feasible and safe in patients with MR conditional pacemakers. Heart rate response to adenosine has to be considered for the choice of pacing modes during CMR.

The use of heart rate turbulence and heart rate variability in the assessment of autonomic regulation and circadian rhythm in patients with systemic lupus erythematosus without apparent heart disease.

PubMed

Poliwczak, A R; Waszczykowska, E; Dziankowska-Bartkowiak, B; Koziróg, M; Dworniak, K

2018-03-01

Background Systemic lupus erythematosus is a progressive autoimmune disease. There are reports suggesting that patients even without overt signs of cardiovascular complications have impaired autonomic function. The aim of this study was to assess autonomic function using heart rate turbulence and heart rate variability parameters indicated in 24-hour ECG Holter monitoring. Methods Twenty-six women with systemic lupus erythematosus and 30 healthy women were included. Twenty-four hour ambulatory ECG-Holter was performed in home conditions. The basic parameters of heart rate turbulence and heart rate variability were calculated. The analyses were performed for the entire day and separately for daytime activity and night time rest. Results There were no statistically significant differences in the basic anthropometric parameters. The mean duration of disease was 11.52 ± 7.42. There was a statistically significant higher turbulence onset (To) value in patients with systemic lupus erythematosus, median To = -0.17% (minimum -1.47, maximum 3.0) versus To = -1.36% (minimum -4.53, maximum -0.41), P < 0.001. There were no such differences for turbulence slope (Ts). In the 24-hour analysis almost all heart rate variability parameters were significantly lower in the systemic lupus erythematosus group than in the healthy controls, including SDANN and r-MSSD and p50NN. Concerning the morning activity and night resting periods, the results were similar as for the whole day. In the control group, higher values in morning activity were noted for parameters that characterise sympathetic activity, especially SDANN, and were significantly lower for parasympathetic parameters, including r-MSSD and p50NN, which prevailed at night. There were no statistically significant changes for systemic lupus erythematosus patients for p50NN and low and very low frequency. There was a positive correlation between disease duration and SDNN, R = 0.417; P < 0.05 and SDANN, R = 0.464; P < 0.05, a negative correlation between low/high frequency ratio and r-MSSD, R = -0.454; P < 0.05; p50NN, R = -0.435; P < 0.05 and high frequency, R = -0.478; P < 0.05. In contrast, there was no statistically significant correlation between heart rate turbulence and other variables evaluated, including disease duration and the type of autoantibodies. Our study confirms the presence of autonomic disorders with respect to both heart rate variability and heart rate turbulence parameters and the presence of diurnal disturbances of sympathetic-parasympathetic balance. Further studies are required.

VANADIUM EXPOSURE ALTERS SPONTANEOUS BEAT RATE AND GENE EXPRESSION OF CULTURED CARDIAC MYOCYTES

EPA Science Inventory

Ambient air pollution particulate matter (PM) exposure is associated with increased morbidity and mortality. Recent toxicological studies report PM-induced changes in a number of cardiac parameters, including heart rate variability, arrhythmias, repolarization, and internal defib...

Changes in Physiology before, during, and after Yawning

PubMed Central

Corey, Timothy P.; Shoup-Knox, Melanie L.; Gordis, Elana B.; Gallup, Gordon G.

2011-01-01

The ultimate function of yawning continues to be debated. Here, we examine physiological measurements taken before, during, and after yawns in humans, in an attempt to identify key proximate mechanisms associated with this behavior. In two separate studies we measured changes in heart rate, lung volume, eye closure, skin conductance, ear pulse, respiratory sinus arrhythmia, and respiratory rate. Data were depicted from 75 s before and after yawns, and analyzed at baseline, during, and immediately following yawns. Increases in heart rate, lung volume, and eye muscle tension were observed during or immediately following yawning. Patterns of physiological changes during yawning were then compared to data from non-yawning deep inhalations. In one study, respiration period increased following the execution of a yawn. Much of the variance in physiology surrounding yawning was specific to the yawning event. This was not the case for deep inhalation. We consider our findings in light of various hypotheses about the function of yawning and conclude that they are most consistent with the brain cooling hypothesis. PMID:22319494

Heart rate complexity: A novel approach to assessing cardiac stress reactivity.

PubMed

Brindle, Ryan C; Ginty, Annie T; Phillips, Anna C; Fisher, James P; McIntyre, David; Carroll, Douglas

2016-04-01

Correlation dimension (D2), a measure of heart rate (HR) complexity, has been shown to decrease in response to acute mental stress and relate to adverse cardiovascular health. However, the relationship between stress-induced changes in D2 and HR has yet to be established. The present studies aimed to assess this relationship systematically while controlling for changes in respiration and autonomic activity. In Study 1 (N = 25) D2 decreased during stress and predicted HR reactivity even after adjusting for changes in respiration rate, and cardiac vagal tone. This result was replicated in Study 2 (N = 162) and extended by including a measure of cardiac sympathetic activity; correlation dimension remained an independent predictor of HR reactivity in a hierarchical linear model containing measures of cardiac parasympathetic and sympathetic activity and their interaction. These results suggest that correlation dimension may provide additional information regarding cardiac stress reactivity above that provided by traditional measures of cardiac autonomic function. © 2015 Society for Psychophysiological Research.

Heart Rate Changes in Electroacupuncture Treated Polycystic Ovary in Rats.

PubMed

Ramadoss, Mukilan; Ramanathan, Gunasekaran; Subbiah, Angelie Jessica; Natrajan, Chidambaranathan

2016-03-01

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. To find the effect of EA on autonomic activity of the heart in Estradiol Valerate (EV) induced PCOS rats. 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. 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. The study concludes that EA treatment has a significant effect on reducing sympathetic tone and decreasing HR in PCOS.

The tell-tale heart: heart rate fluctuations index objective and subjective events during a game of chess.

PubMed

Leone, María J; Petroni, Agustín; Fernandez Slezak, Diego; Sigman, Mariano

2012-01-01

During a decision-making process, the body changes. These somatic changes have been related to specific cognitive events and also have been postulated to assist decision-making indexing possible outcomes of different options. We used chess to analyze heart rate (HR) modulations on specific cognitive events. In a chess game, players have a limited time-budget to make about 40 moves (decisions) that can be objectively evaluated and retrospectively assigned to specific subjectively perceived events, such as setting a goal and the process to reach a known goal. We show that HR signals events: it predicts the conception of a plan, the concrete analysis of variations or the likelihood to blunder by fluctuations before to the move, and it reflects reactions, such as a blunder made by the opponent, by fluctuations subsequent to the move. Our data demonstrate that even if HR constitutes a relatively broad marker integrating a myriad of physiological variables, its dynamic is rich enough to reveal relevant episodes of inner thought.

Utilizing a Collaborative Learning Model to Promote Early Extubation Following Infant Heart Surgery.

PubMed

Mahle, William T; Nicolson, Susan C; Hollenbeck-Pringle, Danielle; Gaies, Michael G; Witte, Madolin K; Lee, Eva K; Goldsworthy, Michelle; Stark, Paul C; Burns, Kristin M; Scheurer, Mark A; Cooper, David S; Thiagarajan, Ravi; Sivarajan, V Ben; Colan, Steven D; Schamberger, Marcus S; Shekerdemian, Lara S

2016-10-01

To determine whether a collaborative learning strategy-derived clinical practice guideline can reduce the duration of endotracheal intubation following infant heart surgery. Prospective and retrospective data collected from the Pediatric Heart Network in the 12 months pre- and post-clinical practice guideline implementation at the four sites participating in the collaborative (active sites) compared with data from five Pediatric Heart Network centers not participating in collaborative learning (control sites). Ten children's hospitals. Data were collected for infants following two-index operations: 1) repair of isolated coarctation of the aorta (birth to 365 d) and 2) repair of tetralogy of Fallot (29-365 d). There were 240 subjects eligible for the clinical practice guideline at active sites and 259 subjects at control sites. Development and application of early extubation clinical practice guideline. After clinical practice guideline implementation, the rate of early extubation at active sites increased significantly from 11.7% to 66.9% (p < 0.001) with no increase in reintubation rate. The median duration of postoperative intubation among active sites decreased from 21.2 to 4.5 hours (p < 0.001). No statistically significant change in early extubation rates was found in the control sites 11.7% to 13.7% (p = 0.63). At active sites, clinical practice guideline implementation had no statistically significant impact on median ICU length of stay (71.9 hr pre- vs 69.2 hr postimplementation; p = 0.29) for the entire cohort. There was a trend toward shorter ICU length of stay in the tetralogy of Fallot subgroup (71.6 hr pre- vs 54.2 hr postimplementation, p = 0.068). A collaborative learning strategy designed clinical practice guideline significantly increased the rate of early extubation with no change in the rate of reintubation. The early extubation clinical practice guideline did not significantly change postoperative ICU length of stay.

Cardiorespiratory interactions previously identified as mammalian are present in the primitive lungfish

PubMed Central

Monteiro, Diana A.; Taylor, Edwin W.; Sartori, Marina R.; Cruz, André L.; Rantin, Francisco T.; Leite, Cleo A. C.

2018-01-01

The present study has revealed that the lungfish has both structural and functional features of its system for physiological control of heart rate, previously considered solely mammalian, that together generate variability (HRV). Ultrastructural and electrophysiological investigation revealed that the nerves connecting the brain to the heart are myelinated, conferring rapid conduction velocities, comparable to mammalian fibers that generate instantaneous changes in heart rate at the onset of each air breath. These respiration-related changes in beat-to-beat cardiac intervals were detected by complex analysis of HRV and shown to maximize oxygen uptake per breath, a causal relationship never conclusively demonstrated in mammals. Cardiac vagal preganglionic neurons, responsible for controlling heart rate via the parasympathetic vagus nerve, were shown to have multiple locations, chiefly within the dorsal vagal motor nucleus that may enable interactive control of the circulatory and respiratory systems, similar to that described for tetrapods. The present illustration of an apparently highly evolved control system for HRV in a fish with a proven ancient lineage, based on paleontological, morphological, and recent genetic evidence, questions much of the anthropocentric thinking implied by some mammalian physiologists and encouraged by many psychobiologists. It is possible that some characteristics of mammalian respiratory sinus arrhythmia, for which functional roles have been sought, are evolutionary relics that had their physiological role defined in ancient representatives of the vertebrates with undivided circulatory systems. PMID:29507882

Cardiorespiratory interactions previously identified as mammalian are present in the primitive lungfish.

PubMed

Monteiro, Diana A; Taylor, Edwin W; Sartori, Marina R; Cruz, André L; Rantin, Francisco T; Leite, Cleo A C

2018-02-01

The present study has revealed that the lungfish has both structural and functional features of its system for physiological control of heart rate, previously considered solely mammalian, that together generate variability (HRV). Ultrastructural and electrophysiological investigation revealed that the nerves connecting the brain to the heart are myelinated, conferring rapid conduction velocities, comparable to mammalian fibers that generate instantaneous changes in heart rate at the onset of each air breath. These respiration-related changes in beat-to-beat cardiac intervals were detected by complex analysis of HRV and shown to maximize oxygen uptake per breath, a causal relationship never conclusively demonstrated in mammals. Cardiac vagal preganglionic neurons, responsible for controlling heart rate via the parasympathetic vagus nerve, were shown to have multiple locations, chiefly within the dorsal vagal motor nucleus that may enable interactive control of the circulatory and respiratory systems, similar to that described for tetrapods. The present illustration of an apparently highly evolved control system for HRV in a fish with a proven ancient lineage, based on paleontological, morphological, and recent genetic evidence, questions much of the anthropocentric thinking implied by some mammalian physiologists and encouraged by many psychobiologists. It is possible that some characteristics of mammalian respiratory sinus arrhythmia, for which functional roles have been sought, are evolutionary relics that had their physiological role defined in ancient representatives of the vertebrates with undivided circulatory systems.

A wider view on gastric erosion: detailed evaluation of complex somatic and behavioral changes in rats treated with indomethacin at gastric ulcerogenic dose.

PubMed

Filaretova, L P; Bagaeva, T R; Morozova, O Y; Zelena, D

2014-10-01

Gastric erosion is widespread side effect of nonsteroidal anti-inflammatory drugs. To examine the complexity of the brain-gut axis regulation, indomethacin-induced gastric erosion formation was studied in connection with somatic and behavioral changes. During a constant telemetric recording of heart rate, body temperature, and locomotion of male rats we examined the effects of 24 h fasting, indomethacin (35 mg/kg s.c.) injection, and refeeding at 4 h. Behavior was analyzed on elevated plus maze (EPM) at 24 h and somatic changes at 72 h. Gastric erosion developed 4 h after indomethacin injection, healed 72 h later contrasted by large injury in the small intestine. As classical signs of chronic stress, body and thymus weight were reduced while adrenal weight was enhanced 72 h after indomethacin injection. Fasting by itself changed all telemetrically recorded parameters with most prominent decrease in heart rate. Indomethacin induced similar diminishing effects with earliest and strongest temperature decrease. As a sign of more anxious phenotype locomotion reducing effect of indomethacin injection was detected on EPM. The EPM-induced temperature elevation was missing in indomethacin-treated animals. Fasting by itself induce somatic changes, which can make the animals more vulnerable to ulcerogenic stimuli. Development of indomethacin-induced gastrointestinal lesions happened in parallel with disturbances of heart rate, core body temperature, and chronic stress-like somatic changes as well as anxiety-like behavior. We have to be more aware of the existence of the brain-gut axis and should study changes in the whole body rather than focusing on a specific organ. elevated plus maze.

Modeling temporal sequences of cognitive state changes based on a combination of EEG-engagement, EEG-workload, and heart rate metrics

PubMed Central

Stikic, Maja; Berka, Chris; Levendowski, Daniel J.; Rubio, Roberto F.; Tan, Veasna; Korszen, Stephanie; Barba, Douglas; Wurzer, David

2014-01-01

The objective of this study was to investigate the feasibility of physiological metrics such as ECG-derived heart rate and EEG-derived cognitive workload and engagement as potential predictors of performance on different training tasks. An unsupervised approach based on self-organizing neural network (NN) was utilized to model cognitive state changes over time. The feature vector comprised EEG-engagement, EEG-workload, and heart rate metrics, all self-normalized to account for individual differences. During the competitive training process, a linear topology was developed where the feature vectors similar to each other activated the same NN nodes. The NN model was trained and auto-validated on combat marksmanship training data from 51 participants that were required to make “deadly force decisions” in challenging combat scenarios. The trained NN model was cross validated using 10-fold cross-validation. It was also validated on a golf study in which additional 22 participants were asked to complete 10 sessions of 10 putts each. Temporal sequences of the activated nodes for both studies followed the same pattern of changes, demonstrating the generalization capabilities of the approach. Most node transition changes were local, but important events typically caused significant changes in the physiological metrics, as evidenced by larger state changes. This was investigated by calculating a transition score as the sum of subsequent state transitions between the activated NN nodes. Correlation analysis demonstrated statistically significant correlations between the transition scores and subjects' performances in both studies. This paper explored the hypothesis that temporal sequences of physiological changes comprise the discriminative patterns for performance prediction. These physiological markers could be utilized in future training improvement systems (e.g., through neurofeedback), and applied across a variety of training environments. PMID:25414629

Maturation of Heart Rate and Blood Pressure Variability during Sleep in Term-Born Infants

PubMed Central

Yiallourou, Stephanie R.; Sands, Scott A.; Walker, Adrian M.; Horne, Rosemary S.C.

2012-01-01

Study Objectives: Abnormal blood pressure control is implicated in the sudden infant death syndrome (SIDS). However, no data exist on normal development of blood pressure control during infancy. This study assessed maturation of autonomic control of blood pressure and heart rate during sleep within the first 6 months of life. Participants: Term infants (n = 31) were studied longitudinally at 2-4 weeks, 2-3 months, and 5-6 months postnatal age. Interventions: Infants underwent daytime polysomnography at each age studied. Blood pressure and heart rate were recorded during quiet (QS) and active (AS) sleep in undisturbed baseline and head-up tilt conditions. Measurements and Results: Autonomic control was assessed using spectral indices of blood pressure and heart rate variability (BPV and HRV) in ranges of low frequency (LF, reflecting sympathetic + parasympathetic activity) and high frequency (HF, parasympathetic activity), total power (LF+HF), and LF/HF ratio (sympathovagal balance). With increasing postnatal age and predominantly during QS, HRV-LF, HRV-HF, and HRV total power increased, while HRV-LF/HF decreased. BPV-LF/HF also decreased with postnatal age. All changes were evident in both baseline and head-up tilt conditions. BPV-LF and BPV total power during tilts were markedly reduced in QS versus AS at each age. Conclusions: In sleeping infants, sympathetic vascular modulation of the circulation decreases with age, while parasympathetic control of heart rate is strengthened. These normative data will aid in the early identification of conditions where autonomic function is impaired, such as in SIDS. Citation: Yiallourou SR; Sands SA; Walker AM; Horne RSC. Maturation of heart rate and blood pressure variability during sleep in term-born infants. SLEEP 2012;35(2):177-186. PMID:22294807

Acute effects of a sarin-like organophosphorus agent, bis(isopropyl methyl)phosphonate, on cardiovascular parameters in anaesthetized, artificially ventilated rats

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

Watanabe, Yoshimasa; Itoh, Takeo, E-mail: titoh@med.nagoya-cu.ac.jp; Shiraishi, Hiroaki

The organophosphorus compound sarin irreversibly inhibits acetylcholinesterase. We examined the acute cardiovascular effects of a sarin-like organophosphorus agent, bis(isopropyl methyl)phosphonate (BIMP), in anaesthetized, artificially ventilated rats. Intravenous administration of BIMP (0.8 mg/kg; the LD50 value) induced a long-lasting increase in blood pressure and tended to increase heart rate. In rats pretreated with the non-selective muscarinic-receptor antagonist atropine, BIMP significantly increased both heart rate and blood pressure. In atropine-treated rats, hexamethonium (antagonist of ganglionic nicotinic receptors) greatly attenuated the BIMP-induced increase in blood pressure without changing the BIMP-induced increase in heart rate. In rats treated with atropine plus hexamethonium, intravenous phentolaminemore » (non-selective α-adrenergic receptor antagonist) plus propranolol (non-selective β-adrenergic receptor antagonist) completely blocked the BIMP-induced increases in blood pressure and heart rate. In atropine-treated rats, the reversible acetylcholinesterase inhibitor neostigmine (1 mg/kg) induced a transient increase in blood pressure, but had no effect on heart rate. These results suggest that in anaesthetized rats, BIMP induces powerful stimulation of sympathetic as well as parasympathetic nerves and thereby modulates heart rate and blood pressure. They may also indicate that an action independent of acetylcholinesterase inhibition contributes to the acute cardiovascular responses induced by BIMP. - Highlights: • A sarin-like agent BIMP markedly increased blood pressure in anaesthetized rats. • Muscarinic receptor blockade enhanced the BIMP-induced increase in blood pressure. • Ganglionic nicotinic receptor blockade attenuated the BIMP-induced response. • Blockade of α- as well as β-receptors attenuated the BIMP-induced response.« less

Assessment of post-laparotomy pain in laboratory mice by telemetric recording of heart rate and heart rate variability

PubMed Central

Arras, Margarete; Rettich, Andreas; Cinelli, Paolo; Kasermann, Hans P; Burki, Kurt

2007-01-01

Background Pain of mild to moderate grade is difficult to detect in laboratory mice because mice are prey animals that attempt to elude predators or man by hiding signs of weakness, injury or pain. In this study, we investigated the use of telemetry to identify indicators of mild-to-moderate post-laparotomy pain. Results Adult mice were subjected to laparotomy, either combined with pain treatment (carprofen or flunixin, 5 mg/kg s/c bid, for 1 day) or without pain relief. Controls received anesthesia and analgesics or vehicle only. Telemetrically measured locomotor activity was undisturbed in all animals, thus confirming that any pain experienced was of the intended mild level. No symptoms of pain were registered in any of the groups by scoring the animals' outer appearance or spontaneous and provoked behavior. In contrast, the group receiving no analgesic treatment after laparotomy demonstrated significant changes in telemetry electrocardiogram recordings: increased heart rate and decreased heart rate variability parameters pointed to sympathetic activation and pain lasting for 24 hours. In addition, core body temperature was elevated. Body weight and food intake were reduced for 3 and 2 days, respectively. Moreover, unstructured cage territory and destroyed nests appeared for 1–2 days in an increased number of animals in this group only. In controls these parameters were not affected. Conclusion In conclusion, real-time telemetric recordings of heart rate and heart rate variability were indicative of mild-to-moderate post-laparotomy pain and could define its duration in our mouse model. This level of pain cannot easily be detected by direct observation. PMID:17683523

The effect of orthostasis on recurrence quantification analysis of heart rate and blood pressure dynamics.

PubMed

Javorka, M; Turianikova, Z; Tonhajzerova, I; Javorka, K; Baumert, M

2009-01-01

The purpose of this paper is to investigate the effect of orthostatic challenge on recurrence plot based complexity measures of heart rate and blood pressure variability (HRV and BPV). HRV and BPV complexities were assessed in 28 healthy subjects over 15 min in the supine and standing positions. The complexity of HRV and BPV was assessed based on recurrence quantification analysis. HRV complexity was reduced along with the HRV magnitude after changing from the supine to the standing position. In contrast, the BPV magnitude increased and BPV complexity decreased upon standing. Recurrence quantification analysis (RQA) of HRV and BPV is sensitive to orthostatic challenge and might therefore be suited to assess changes in autonomic neural outflow to the cardiovascular system.

Physiological plasticity of cardiorespiratory function in a eurythermal marine teleost, the longjaw mudsucker, Gillichthys mirabilis.

PubMed

Jayasundara, Nishad; Somero, George N

2013-06-01

An insufficient supply of oxygen under thermal stress is thought to define thermal optima and tolerance limits in teleost fish. When under thermal stress, cardiac function plays a crucial role in sustaining adequate oxygen supply for respiring tissues. Thus, adaptive phenotypic plasticity of cardiac performance may be critical for modifying thermal limits during temperature acclimation. Here we investigated effects of temperature acclimation on oxygen consumption, cardiac function and blood oxygen carrying capacity of a eurythermal goby fish, Gillichthys mirabilis, acclimated to 9, 19 and 26°C for 4 weeks. Acclimation did not alter resting metabolic rates or heart rates; no compensation of rates was observed at acclimation temperatures. However, under an acute heat ramp, warm-acclimated fish exhibited greater heat tolerance (CTmax=33.3, 37.1 and 38.9°C for 9°C-, 19°C- and 26°C-acclimated fish, respectively) and higher cardiac arrhythmia temperatures compared with 9°C-acclimated fish. Heart rates measured under an acute heat stress every week during 28 days of acclimation suggested that both maximum heart rates and temperature at onset of maximum heart rates changed over time with acclimation. Hemoglobin levels increased with acclimation temperature, from 35 g l(-1) in 9°C-acclimated fish to 60-80 g l(-1) in 19°C- and 26°C-acclimated fish. Oxygen consumption rates during recovery from acute heat stress showed post-stress elevation in 26°C-acclimated fish. These data, coupled with elevated resting metabolic rates and heart rates at warm temperatures, suggest a high energetic cost associated with warm acclimation in G. mirabilis. Furthermore, acclimatory capacity appears to be optimized at 19°C, a temperature shown by behavioral studies to be close to the species' preferred temperature.

Clinical recommendations for high altitude exposure of individuals with pre-existing cardiovascular conditions

PubMed Central

Parati, Gianfranco; Agostoni, Piergiuseppe; Basnyat, Buddha; Bilo, Grzegorz; Brugger, Hermann; Coca, Antonio; Festi, Luigi; Giardini, Guido; Lironcurti, Alessandra; Luks, Andrew M; Maggiorini, Marco; Modesti, Pietro A; Swenson, Erik R; Williams, Bryan; Bärtsch, Peter; Torlasco, Camilla

2018-01-01

Abstract Take home figureAdapted from Bärtsch and Gibbs2 Physiological response to hypoxia. Life-sustaining oxygen delivery, in spite of a reduction in the partial pressure of inhaled oxygen between 25% and 60% (respectively at 2500 m and 8000 m), is ensured by an increase in pulmonary ventilation, an increase in cardiac output by increasing heart rate, changes in vascular tone, as well as an increase in haemoglobin concentration. BP, blood pressure; HR, heart rate; PaCO2, partial pressure of arterial carbon dioxide. PMID:29340578

Effect of uterine contractions on fetal heart rate in pregnancy: a prospective observational study.

PubMed

Sletten, Julie; Kiserud, Torvid; Kessler, Jörg

2016-10-01

The new Holter monitoring technology enables long-term electrocardiographic recording of the fetal heart rate without discomfort for the mother. The aim of the study was to assess the feasibility of a fetal Holter monitor. This technology was further used to study fetal heart rate outside the hospital setting during normal daily activities and to test the hypothesis that uterine activity during pregnancy influences fetal heart rate. Prospective observational study including 12 healthy pregnant women at 20-40 weeks of gestation. Data were collected using the Monica AN24 system. Outcome measures were fetal heart rate, maternal heart rate, and uterine activity categorized according to the strength of the electrohysterographic signal. The recordings had a median length of 18.8 h, and fetal heart rate and maternal heart rate were obtained with success rates of 73.1 and 99.9%, respectively. Uterine activity was found to affect fetal heart rate in all participants. Compared with the basal tone and mild levels of uterine activity, moderate and strong levels of uterine activity were associated with increases in fetal heart rate of 4.0 and 5.7 beats/min, respectively. At night, the corresponding increases were 4.9 and 7.6 beats/min. Linear correlations were found between maternal heart rate and fetal heart rate in 11 of the 12 cases, with a mean coefficient beta of 0.189. Both maternal heart rate and fetal heart rate exhibited a diurnal pattern, with lower heart rates being recorded at night. Uterine activity during pregnancy is associated with a graded response in fetal heart rate and may represent a physiological challenge for the development and adaptation of the fetal cardiovascular system. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

Within-session responses to high-intensity interval training in spinal cord injury.

PubMed

Astorino, Todd Anthony; Thum, Jacob S

2018-02-01

Completion of high-intensity interval training (HIIT) increases maximal oxygen uptake and health status, yet its feasibility in persons with spinal cord injury is unknown. To compare changes in cardiorespiratory and metabolic variables between two interval training regimes and moderate intensity exercise. Nine adults with spinal cord injury (duration = 6.8 ± 6.2 year) initially underwent determination of peak oxygen uptake. During subsequent sessions, they completed moderate intensity exercise, HIIT, or sprint interval training. Oxygen uptake, heart rate, and blood lactate concentration were measured. Oxygen uptake and heart rate increased (p < 0.05) during both interval training sessions and were similar (p > 0.05) to moderate intensity exercise. Peak oxygen uptake and heart rate were higher (p < 0.05) with HIIT (90% peak oxygen uptake and 99% peak heart rate) and sprint interval training (80% peak oxygen uptake and 96% peak heart rate) versus moderate intensity exercise. Despite a higher intensity and peak cardiorespiratory strain, all participants preferred interval training versus moderate exercise. Examining long-term efficacy and feasibility of interval training in this population is merited, considering that exercise intensity is recognized as the most important variable factor of exercise programming to optimize maximal oxygen uptake. Implications for Rehabilitation Spinal cord injury (SCI) reduces locomotion which impairs voluntary physical activity, typically resulting in a reduction in peak oxygen uptake and enhanced chronic disease risk. In various able-bodied populations, completion of high-intensity interval training (HIIT) has been consistently reported to improve cardiorespiratory fitness and other health-related outcomes, although its efficacy in persons with SCI is poorly understood. Data from this study in 9 men and women with SCI show similar changes in oxygen uptake and heart in response to HIIT compared to a prolonged bout of aerobic exercise, although peak values were higher in response to HIIT. Due to the higher peak metabolic strain induced by HIIT as well as universal preference for this modality versus aerobic exercise as reported in this study, further work testing utility of HIIT in this population is merited.

The effect of sham feeding on neurocardiac regulation in healthy human volunteers

PubMed Central

Kamath, Markad V; Spaziani, Robert; Ullal, Sangeeta; Tougas, Gervais; Guzman, Juan C; Morillo, Carlos; Capogna, Joshua; Al-Bayati, Mohammed; Armstrong, David

2007-01-01

BACKGROUND: Distension and electrical stimuli in the esophagus alter heart rate variability (HRV) consistent with activation of vagal afferent and efferent pathways. Sham feeding stimulates gastric acid secretion by means of vagal efferent pathways. It is not known, however, whether activation of vagal efferent pathways is organ- or stimulus-specific. OBJECTIVE: To test the hypothesis that sham feeding increases the high frequency (HF) component of HRV, indicating increased neurocardiac vagal activity in association with the known, vagally mediated, increase in gastric acid secretion. METHODS: Continuous electrocardiography recordings were obtained in 12 healthy, semirecumbent subjects during consecutive 45 min baseline, 20 min sham feeding (standard hamburger meal) and 45 min recovery periods. The R-R intervals and beat-to-beat heart rate signal were determined from digitized electrocardiography recordings; power spectra were computed from the heart rate signal to determine sympathetic (low frequency [LF]) and vagal (HF) components of HRV. RESULTS: Heart rate increased during sham feeding (median 70.8 beats/min, 95% CI 66.0 to 77.6; P<0.001), compared with baseline (63.6, 95% CI 60.8 to 70.0) and returned to baseline levels within 45 min. Sham feeding increased the LF to HF area ratio (median: 1.55, 95% C.I 1.28 to 1.77; P<0.021, compared with baseline (1.29, 95% CI 1.05 to 1.46); this increase in LF to HF area ratio was associated with a decrease in the HF component of HRV. CONCLUSIONS: Sham feeding produces a reversible increase in heart rate that is attributable to a decrease in neurocardiac parasympathetic activity despite its known ability to increase vagally mediated gastric acid secretion. These findings suggest that concurrent changes in cardiac and gastric function are modulated independently by vagal efferent fibres and that vagally mediated changes in organ function are stimulus- and organ-specific. PMID:18026575

Acute effects of visits to urban green environments on cardiovascular physiology in women: A field experiment.

PubMed

Lanki, Timo; Siponen, Taina; Ojala, Ann; Korpela, Kalevi; Pennanen, Arto; Tiittanen, Pekka; Tsunetsugu, Yuko; Kagawa, Takahide; Tyrväinen, Liisa

2017-11-01

Epidemiological studies have reported positive associations between the amount of green space in the living environment and mental and cardiovascular human health. In a search for effect mechanisms, field studies have found short-term visits to green environments to be associated with psychological stress relief. Less evidence is available on the effect of visits on cardiovascular physiology. To evaluate whether visits to urban green environments, in comparison to visits to a built-up environment, lead to beneficial short-term changes in indicators of cardiovascular health. Thirty-six adult female volunteers visited three different types of urban environments: an urban forest, an urban park, and a built-up city centre, in Helsinki, Finland. The visits consisted of 15min of sedentary viewing, and 30min of walking. During the visits, blood pressure and heart rate were measured, and electrocardiogram recorded for the determination of indicators of heart rate variability. In addition, levels of respirable ambient particles and environmental noise were monitored. Visits to the green environments were associated with lower blood pressure (viewing period only), lower heart rate, and higher indices of heart rate variability [standard deviation of normal-to-normal intervals (SDNN), high frequency power] than visits to the city centre. In the green environments, heart rate decreased and SDNN increased during the visit. Associations between environment and indicators of cardiovascular health weakened slightly after inclusion of particulate air pollution and noise in the models. Visits to urban green environments are associated with beneficial short-term changes in cardiovascular risk factors. This can be explained by psychological stress relief with contribution from reduced air pollution and noise exposure during the visits. Future research should evaluate the amount of exposure to green environments needed for longer-term benefits for cardiovascular health. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Hemodynamic effects of L-threo-3,4-dihydroxyphenylserine (Droxidopa) in hypotensive individuals with spinal cord injury.

PubMed

Wecht, Jill M; Rosado-Rivera, Dwindally; Weir, Joseph P; Ivan, Adrian; Yen, Christina; Bauman, William A

2013-10-01

To determine the effect of an escalating dose of droxidopa (100, 200, and 400 mg) compared with placebo on seated blood pressure (BP) in hypotensive individuals with spinal cord injury (SCI). Secondarily, we aimed to determine the effect of droxidopa on (1) supine BP and heart rate, (2) the change in BP and heart rate when these individuals were transferred from the supine to the seated position, and (3) adverse event (AE) reporting. Open-label dose titration trial. A Veterans Administration Medical Center. Participants with SCI (C3-T12) (N=10) were studied during 4 laboratory visits. Subjects visited the laboratory for about 5 hours on each visit, which incorporated a 30-minute seated baseline, a 30- to 60-minute supine, and a 4-hour seated postdrug observation. Placebo on visit 1, droxidopa 100 mg on visit 2, droxidopa 200 mg on visit 3, and droxidopa 400 mg on visit 4. BP and heart rate changes from baseline to the postdrug period, orthostatic heart rate and BP responses, and subjective AE reporting. Seated BP was significantly elevated with 400 mg droxidopa compared with placebo and 100 mg droxidopa for 3 hours and was elevated for 2 hours compared with 200 mg droxidopa. Increase in supine BP was not worsened following droxidopa, and the expected fall in BP when transferred to the seated position was prevented with droxidopa 200 and 400 mg. There were no significant differences in the heart rate response or AE reporting among the study visits. Our preliminary findings suggest that droxidopa, at the doses tested, does not cause excessive increases in supine BP and the 400-mg dose appears to be effective at increasing seated BP for up to 3 hours in persons with SCI. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Dynamic QT Interval Changes from Supine to Standing in Healthy Children.

PubMed

Dionne, Audrey; Fournier, Anne; Dahdah, Nagib; Abrams, Dominic; Khairy, Paul; Abadir, Sylvia

2018-01-01

QT-interval variations in response to exercise-induced increases in heart rate have been reported in children and adults in the diagnosis of long QT syndrome (LQTS). A quick standing challenge has been proposed as an alternative provocative test in adults, with no pediatric data yet available. A standing test was performed in 100 healthy children (mean age, 9.7 ± 3.1 years) after 10 minutes in a supine position with continuous electrocardiographic recording. QT intervals were measured at baseline, at maximal heart rate, at maximal QT, and at each minute of a 5-minute recovery while standing. Measurements were taken in leads II/V 5 and were corrected for heart rate (QTc). On standing, the heart rate increased by 29 ± 10 beats per minute (bpm). The QT interval was similar at baseline and on standing (394 ± 34 ms vs 394 ± 34 ms; P = 1.0). However, QTc increased from 426 ± 21 to 509 ± 41 ms (P < 0.001). The 95th percentile for QTc at baseline and maximal heart rate was 457 ms and 563 ms, respectively. At 1 minute of recovery, the QT interval was shorter (375 ± 31 ms) compared with baseline (394 ± 34 ms; P < 0.001) and standing (394 ± 34 ms; P < 0.001). QTc reached baseline values after 1 minute of recovery and remained stable thereafter (423 ± 23 ms at 1 minute; 426 ± 22 ms at 5 minutes; P = 1.0). This first characterization of QTc changes on standing in children shows substantial alterations, which are greater than those seen in adults. Two-thirds of the children would have been misclassified as having LQTS by adult criteria, indicating the need to create child-specific standards. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

The Effect of Adenotonsillectomy for Childhood Sleep Apnea on Cardiometabolic Measures

PubMed Central

Quante, Mirja; Wang, Rui; Weng, Jia; Rosen, Carol L.; Amin, Raouf; Garetz, Susan L.; Katz, Eliot; Paruthi, Shalini; Arens, Raanan; Muzumdar, Hiren; Marcus, Carole L.; Ellenberg, Susan; Redline, Susan

2015-01-01

Study Objectives: Obstructive sleep apnea syndrome (OSAS) has been associated with cardiometabolic disease in adults. In children, this association is unclear. We evaluated the effect of early adenotonsillectomy (eAT) for treatment of OSAS on blood pressure, heart rate, lipids, glucose, insulin, and C-reactive protein. We also analyzed whether these parameters at baseline and changes at follow-up correlated with polysomnographic indices. Design: Data collected at baseline and 7-mo follow-up were analyzed from a randomized controlled trial, the Childhood Adenotonsillectomy Trial (CHAT). Setting: Clinical referral setting from multiple centers. Participants: There were 464 children, ages 5 to 9.9 y with OSAS without severe hypoxemia. Interventions: Randomization to eAT or Watchful Waiting with Supportive Care (WWSC). Measurements and Results: There was no significant change of cardiometabolic parameters over the 7-mo interval in the eAT group compared to WWSC group. However, overnight heart rate was incrementally higher in association with baseline OSAS severity (average heart rate increase of 3 beats per minute [bpm] for apnea-hypopnea index [AHI] of 2 versus 10; [standard error = 0.60]). Each 5-unit improvement in AHI and 5 mmHg improvement in peak end-tidal CO2 were estimated to reduce heart rate by 1 and 1.5 bpm, respectively. An increase in N3 sleep also was associated with small reductions in systolic blood pressure percentile. Conclusions: There is little variation in standard cardiometabolic parameters in children with obstructive sleep apnea syndrome (OSAS) but without severe hypoxemia at baseline or after intervention. Of all measures, overnight heart rate emerged as the most sensitive parameter of pediatric OSAS severity. Clinical Trial Registration: Clinicaltrials.gov (#NCT00560859) Citation: Quante M, Wang R, Weng J, Rosen CL, Amin R, Garetz SL, Katz E, Paruthi S, Arens R, Muzumdar H, Marcus CL, Ellenberg S, Redline S. The effect of adenotonsillectomy for childhood sleep apnea on cardiometabolic measures. SLEEP 2015;38(9):1395–1403. PMID:25669177

CCISS, Vascular and BP Reg: Canadian space life science research on ISS

NASA Astrophysics Data System (ADS)

Hughson, Richard L.; Shoemaker, J. Kevin; Arbeille, Philippe

2014-11-01

A comprehensive goal of the Canadian Space Agency studies (CCISS, Vascular and BP Reg) has been to investigate the efficacy of current exercise countermeasures to maintain cardiovascular and cerebrovascular health on return to Earth after up to 6-months in space. Results from the CCISS experiments revealed no significant change of in-flight heart rate during daily activities or sleep, and small, but variable between astronauts, post-flight elevation. The between astronaut differences were exaggerated during measurement of spontaneous baroreflex slope, which was reduced post-flight (P<0.05) during paced breathing with 3 astronauts having significant correlations between reduced baroreflex and reduced RR-interval (consistent with reduced fitness). Cerebrovascular autoregulation and CO2 response were mildly impaired after flight. Some loss of in-flight fitness of astronauts in Vascular was reflected by the increase in HR at a work rate of 161±46 W of 12.3±10.5 bpm, 10.4±5.9 bpm and 13.4±5.7 bpm for early-flight, late-flight and R+1, respectively. On return to gravity, changes in resting heart rate for supine (5.9±3.5 bpm), sit (8.1±3.3 bpm) and stand (10.3±10.0 bpm) were small but variable between individuals (from -5 bpm to +20 bpm in post-flight standing) and not related to the change in exercise heart rate. In Vascular astronauts, pulse wave transit time measured to the finger tended to be reduced post-flight and carotid artery distensibility was significantly reduced (P=0.03, and n=6). The heart rate and baroreflex data suggest that some astronauts return with cardiovascular deconditioning in spite of the exercise regimes. However, greater arterial stiffness is common among all astronauts studied to date. The new CSA project, BP Reg, will monitor inflight blood pressure in an attempt to identify astronauts in greater need for countermeasures. Future research should focus on whether Vascular changes in astronauts might make them an appropriate model to study the mechanisms of arterial aging on Earth.

E-bra with nanosensors, smart electronics and smart phone communication network for heart rate monitoring

NASA Astrophysics Data System (ADS)

Varadan, Vijay K.; Kumar, Prashanth S.; Oh, Sechang; Mathur, Gyanesh N.; Rai, Pratyush; Kegley, Lauren

2011-04-01

Heart related ailments have been a major cause for deaths in both men and women in United States. Since 1985, more women than men have died due to cardiac or cardiovascular ailments for reasons that are not well understood as yet. Lack of a deterministic understanding of this phenomenon makes continuous real time monitoring of cardiovascular health the best approach for both early detection of pathophysiological changes and events indicative of chronic cardiovascular diseases in women. This approach requires sensor systems to be seamlessly mounted on day to day clothing for women. With this application in focus, this paper describes a e-bra platform for sensors towards heart rate monitoring. The sensors, nanomaterial or textile based dry electrodes, capture the heart activity signals in form Electrocardiograph (ECG) and relay it to a compact textile mountable amplifier-wireless transmitter module for relay to a smart phone. The ECG signal, acquired on the smart phone, can be transmitted to the cyber space for post processing. As an example, the paper discusses the heart rate estimation and heart rate variability. The data flow from sensor to smart phone to server (cyber infrastructure) has been discussed. The cyber infrastructure based signal post processing offers an opportunity for automated emergency response that can be initiated from the server or the smartphone itself. Detailed protocols for both the scenarios have been presented and their relevance to the present emergency healthcare response system has been discussed.

System analysis of the dynamic response of the coronary circulation to a sudden change in heart rate.

PubMed

Dankelman, J; Stassen, H G; Spaan, J A

1990-03-01

In this study the response of driving pressure/flow ration on an abrupt change in heart rate was analysed. The difference between the response obtained with constant pressure and constant flow perfusion was also studied. The responses show a fast initial reversed phase followed by a slow phase caused by regulation. To test whether the initial phase could be the result of mechanical changes in the coronary circulation, a model for regulation was extended by the addition of four different mechanical models originating from the literature. These extended models were able to explain the fast initial phase. However, the mechanical model consisting of an intramyocardial compliance (C = 0.08 ml mm Hg-1 100 g-1) with a variable venous resistance, and the model consisting of a waterfall and a small compliance (C = 0.007 ml mm Hg-1 100g-1) both explained these responses best. The analysis showed that there is no direct relationship between rate of change of vascular tone and rate of change of pressure/flow ratio. However, on the basis of the two extended models, it can be predicted that the half-time for the response of regulation to be complete is about 9s with constant pressure perfusion and 15 s with constant flow perfusion.

Influence of Dai-kenchu-to (DKT) on human portal blood flow.

PubMed

Ogasawara, Takashi; Morine, Yuji; Ikemoto, Tetsuya; Imura, Satoru; Fujii, Masahiko; Soejima, Yuji; Shimada, Mitsuo

2008-01-01

Dai-kenchu-to (DKT) is known as an herbal medicine used for postoperative ileus. However, no report exists about the effect of DKT on portal blood flow. The aim of this study is to clarify the influence of DKT on portal blood flow. To healthy volunteers (Healthy; n = 6), cirrhotic patients (Cirrhosis; n = 7) and liver-transplant patients (LTx; n = 3), DKT (2.5g) with 100mL of warm water was orally administrated in the DKT group, and only warm water was administrated in the control group. The portal blood flow rate (M-VEL: cm/sec.) and portal blood flow (Flow volume: mL/min.) was measured each time after administration using an ultrasonic Doppler method. Furthermore, the arterial blood pressure and heart rate was measured at the same time points. In the DKT group, a significant increase of M-VEL (120%) and flow volume (150%) 30 minutes after administration was observed in both Healthy and Cirrhosis in comparison with the control group. In LTx, there was also a significant increase of flow volume (128%) 30 minutes after administration. However, there was no change in average blood pressure and heart rate in all groups. DKT increases portal blood flow in early phase after oral administration without any significant changes in the blood pressure and heart rate.

Effect of beta-adrenergic blockade with timolol on myocardial blood flow during exercise after myocardial infarction in the dog.

PubMed

Herzog, C A; Aeppli, D P; Bache, R J

1984-12-01

The effect of beta-adrenergic blockade with timolol (40 micrograms/kg) on myocardial blood flow during rest and graded treadmill exercise was assessed in 12 chronically instrumented dogs 10 to 14 days after myocardial infarction was produced by acute left circumflex coronary artery occlusion. During exercise at comparable external work loads, the heart rate-systolic blood pressure product was significantly decreased after timilol, with concomitant reductions of myocardial blood flow in normal, border and central ischemic areas (p less than 0.001) and increases in subendocardial/subepicardial blood flow ratios (p less than 0.05). In addition to the blunted chronotropic response to exercise, timolol exerted an effect on myocardial blood flow that was not explained by changes in heart rate or blood pressure. At comparable rate-pressure products during exercise, total myocardial blood flow was 24% lower after timolol (p less than 0.02) and flow was redistributed from subepicardium to subendocardium in all myocardial regions. Thus, timolol altered myocardial blood flow during exercise by two separate mechanisms: a negative chronotropic effect, and a significant selective reduction of subepicardial perfusion independent of changes in heart rate or blood pressure with transmural redistribution of flow toward the subendocardium.

Heart rate and physical activity patterns in persons with profound intellectual and multiple disabilities.

PubMed

Waninge, Aly; van der Putten, Annette A J; Stewart, Roy E; Steenbergen, Bert; van Wijck, Ruud; van der Schans, Cees P

2013-11-01

Because physical fitness and health are related to physical activity, it is important to gain an insight into the physical activity levels of persons with profound intellectual and multiple disabilities (PIMD). The purpose of this study was to examine heart rate patterns to measure the activity levels of persons with PIMD and to analyze these heart rate patterns according to participant characteristics, observed level of activity, days, and time of day. The heart rate patterns of 24 participants with PIMD were measured continuously using a heart rate monitor for 8 h · d for a period of 6 days. Physical activity levels were measured with questionnaires. Data were analyzed using multilevel analysis. The results indicate that the participants use only 32% of their heart rate reserve over 6 days. The intensity of heart rate reserve ranged from 1 to 62%. On a given day, wide ranges in heart rates between participants and within persons were observed. Between days, only small ranges in the heart rate were found. The participants could be grouped into 4 classes according to their heart rate. In addition, factors such as time of day, physical activity, and age are significantly related to heart rate patterns. In conclusion, this study is an important first step in exploring activity patterns based on heart rate patterns in persons with PIMD. The participants used relatively small fractions of their heart rate reserves. Time of day and age appear to have a considerable influence on heart rate patterns. The observed classes in heart rate patterns suggest that other probably more personal and psychosocial factors have significant influences on heart rate patterns, as well.

Arterial viscoelasticity: role in the dependency of pulse wave velocity on heart rate in conduit arteries.

PubMed

Xiao, Hanguang; Tan, Isabella; Butlin, Mark; Li, Decai; Avolio, Alberto P

2017-06-01

Experimental investigations have established that the stiffness of large arteries has a dependency on acute heart rate (HR) changes. However, the possible underlying mechanisms inherent in this HR dependency have not been well established. This study aimed to explore a plausible viscoelastic mechanism by which HR exerts an influence on arterial stiffness. A multisegment transmission line model of the human arterial tree incorporating fractional viscoelastic components in each segment was used to investigate the effect of varying fractional order parameter (α) of viscoelasticity on the dependence of aortic arch to femoral artery pulse wave velocity (afPWV) on HR. HR was varied from 60 to 100 beats/min at a fixed mean flow of 100 ml/s. PWV was calculated by intersecting tangent method (afPWV Tan ) and by phase velocity from the transfer function (afPWV TF ) in the time and frequency domain, respectively. PWV was significantly and positively associated with HR for α ≥ 0.6; for α = 0.6, 0.8, and 1, HR-dependent changes in afPWV Tan were 0.01 ± 0.02, 0.07 ± 0.04, and 0.22 ± 0.09 m/s per 5 beats/min; HR-dependent changes in afPWV TF were 0.02 ± 0.01, 0.12 ± 0.00, and 0.34 ± 0.01 m/s per 5 beats/min, respectively. This crosses the range of previous physiological studies where the dependence of PWV on HR was found to be between 0.08 and 0.10 m/s per 5 beats/min. Therefore, viscoelasticity of the arterial wall could contribute to mechanisms through which large artery stiffness changes with changing HR. Physiological studies are required to confirm this mechanism. NEW & NOTEWORTHY This study used a transmission line model to elucidate the role of arterial viscoelasticity in the dependency of pulse wave velocity on heart rate. The model uses fractional viscoelasticity concepts, which provided novel insights into arterial hemodynamics. This study also provides a means of assessing the clinical manifestation of the association of pulse wave velocity and heart rate. Copyright © 2017 the American Physiological Society.

1H nuclear magnetic resonance studies of sarcoplasmic oxygenation in the red cell-perfused rat heart.

PubMed

Jelicks, L A; Wittenberg, B A

1995-05-01

The proximal histidine N delta H proton of deoxymyoglobin experiences a large hyperfine shift resulting in its 1H nuclear magnetic resonance (NMR) signal appearing at approximately 76 ppm (at 35 degrees C), downfield of the diamagnetic spectral region. 1H NMR of this proton is used to monitor sarcoplasmic oxygen pressure in isolated perfused rat heart. This method monitors intracellular oxygenation in the whole heart and does not reflect oxygenation in a limited region. The deoxymyoglobin resonance intensity is reduced upon conversion of myoglobin to the ferric form by sodium nitrite. 1H resonances of the N delta H protons of the alpha and beta subunits of bovine deoxyhemoglobin do not interfere with the measurement of myoglobin deoxygenation in blood-perfused rat heart. We find that steady-state myoglobin deoxygenation is increased progressively (and reversibly) as oxygenation of the perfusing medium is decreased in both saline and red blood cell-perfused hearts at constant work output. An eightfold increase in the heart rate of the blood-perfused heart resulted in no change in the deoxymyoglobin signal intensity. Intracellular PO2 of myoglobin-containing cells is maintained remarkably constant in changing work states.

Effects of p-Synephrine alone and in Combination with Selected Bioflavonoids on Resting Metabolism, Blood Pressure, Heart Rate and Self-Reported Mood Changes

PubMed Central

Stohs, Sidney J.; Preuss, Harry G; Keith, Samuel C.; Keith, Patti L.; Miller, Howard; Kaats, Gilbert R.

2011-01-01

Bitter orange (Citrus aurantium) extract is widely used in dietary supplements for weight management and sports performance. Its primary protoalkaloid is p-synephrine. Most studies involving bitter orange extract and p-synephrine have used products with multiple ingredients. The current study assessed the thermogenic effects of p-synephrine alone and in conjunction with the flavonoids naringin and hesperidin in a double-blinded, randomized, placebo-controlled protocol with 10 subjects per treatment group. Resting metabolic rates (RMR), blood pressure, heart rates and a self-reported rating scale were determined at baseline and 75 min after oral ingestion of the test products in V-8 juice. A decrease of 30 kcal occurred in the placebo control relative to baseline. The group receiving p-synephrine (50 mg) alone exhibited a 65 kcal increase in RMR as compared to the placebo group. The consumption of 600 mg naringin with 50 mg p-synephrine resulted in a 129 kcal increase in RMR relative to the placebo group. In the group receiving 100 mg hesperidin in addition to the 50 mg p-synephrine plus 600 mg naringin, the RMR increased by 183 kcal, an increase that was statistically significant with respect to the placebo control (p<0.02). However, consuming 1000 mg hesperidin with 50 mg p-synephrine plus 600 mg naringin resulted in a RMR that was only 79 kcal greater than the placebo group. None of the treatment groups exhibited changes in heart rate or blood pressure relative to the control group, nor there were no differences in self-reported ratings of 10 symptoms between the treatment groups and the control group. This unusual finding of a thermogenic combination of ingredients that elevated metabolic rates without corresponding elevations in blood pressure and heart-rates warrants longer term studies to assess its value as a weight control agent. PMID:21537493

Metformin improves cardiac function in mice with heart failure after myocardial infarction by regulating mitochondrial energy metabolism.

PubMed

Sun, Dan; Yang, Fei

2017-04-29

To investigate whether metformin can improve the cardiac function through improving the mitochondrial function in model of heart failure after myocardial infarction. Male C57/BL6 mice aged about 8 weeks were selected and the anterior descending branch was ligatured to establish the heart failure model after myocardial infarction. The cardiac function was evaluated via ultrasound after 3 days to determine the modeling was successful, and the mice were randomly divided into two groups. Saline group (Saline) received the intragastric administration of normal saline for 4 weeks, and metformin group (Met) received the intragastric administration of metformin for 4 weeks. At the same time, Shame group (Sham) was set up. Changes in cardiac function in mice were detected at 4 weeks after operation. Hearts were taken from mice after 4 weeks, and cell apoptosis in myocardial tissue was detected using TUNEL method; fresh mitochondria were taken and changes in oxygen consumption rate (OCR) and respiratory control rate (RCR) of mitochondria in each group were detected using bio-energy metabolism tester, and change in mitochondrial membrane potential (MMP) of myocardial tissue was detected via JC-1 staining; the expressions and changes in Bcl-2, Bax, Sirt3, PGC-1α and acetylated PGC-1α in myocardial tissue were detected by Western blot. RT-PCR was used to detect mRNA levels in Sirt3 in myocardial tissues. Metformin improved the systolic function of heart failure model rats after myocardial infarction and reduced the apoptosis of myocardial cells after myocardial infarction. Myocardial mitochondrial respiratory function and membrane potential were decreased after myocardial infarction, and metformin treatment significantly improved the mitochondrial respiratory function and mitochondrial membrane potential; Metformin up-regulated the expression of Sirt3 and the activity of PGC-1α in myocardial tissue of heart failure after myocardial infarction. Metformin decreases the acetylation level of PGC-1α through up-regulating Sirt3, mitigates the damage to mitochondrial membrane potential of model of heart failure after myocardial infarction and improves the respiratory function of mitochondria, thus improving the cardiac function of mice. Copyright © 2017. Published by Elsevier Inc.

Construct validity of the Heart Failure Screening Tool (Heart-FaST) to identify heart failure patients at risk of poor self-care: Rasch analysis.

PubMed

Reynolds, Nicholas A; Ski, Chantal F; McEvedy, Samantha M; Thompson, David R; Cameron, Jan

2018-02-14

The aim of this study was to psychometrically evaluate the Heart Failure Screening Tool (Heart-FaST) via: (1) examination of internal construct validity; (2) testing of scale function in accordance with design; and (3) recommendation for change/s, if items are not well adjusted, to improve psychometric credential. Self-care is vital to the management of heart failure. The Heart-FaST may provide a prospective assessment of risk, regarding the likelihood that patients with heart failure will engage in self-care. Psychometric validation of the Heart-FaST using Rasch analysis. The Heart-FaST was administered to 135 patients (median age = 68, IQR = 59-78 years; 105 males) enrolled in a multidisciplinary heart failure management program. The Heart-FaST is a nurse-administered tool for screening patients with HF at risk of poor self-care. A Rasch analysis of responses was conducted which tested data against Rasch model expectations, including whether items serve as unbiased, non-redundant indicators of risk and measure a single construct and that rating scales operate as intended. The results showed that data met Rasch model expectations after rescoring or deleting items due to poor discrimination, disordered thresholds, differential item functioning, or response dependence. There was no evidence of multidimensionality which supports the use of total scores from Heart-FaST as indicators of risk. Aggregate scores from this modified screening tool rank heart failure patients according to their "risk of poor self-care" demonstrating that the Heart-FaST items constitute a meaningful scale to identify heart failure patients at risk of poor engagement in heart failure self-care. © 2018 John Wiley & Sons Ltd.

Quantifying the Physiological Stress Response to Simulated Maritime Pilotage Tasks

PubMed Central

Main, Luana C.; Wolkow, Alexander; Chambers, Timothy P.

2017-01-01

Objective: The aim of this study was to quantify the stress associated with performing maritime pilotage tasks in a high-fidelity simulator. Methods: Eight trainee and 13 maritime pilots completed two simulated pilotage tasks of varying complexity. Salivary cortisol samples were collected pre- and post-simulation for both trials. Heart rate was measured continuously throughout the study. Results: Significant changes in salivary cortisol (P = 0.000, η2 = 0.139), average (P = 0.006, η2 = 0.087), and peak heart rate (P = 0.013, η2 = 0.077) from pre- to postsimulation were found. Varying task complexity did partially influence stress response; average (P = 0.016, η2 = 0.026) and peak heart rate (P = 0.034, η2 = 0.020) were higher in the experimental condition. Trainees also recorded higher average (P = 0.000, η2 = 0.054) and peak heart rates (P = 0.027, η2 = 0.022). Conclusion: Performing simulated pilotage tasks evoked a measurable stress response in both trainee and expert maritime pilots. PMID:28922309

Estimated energy expenditure of nursing assistants in long term care.

PubMed

Olson, Darcie L; King, Phyllis M

2012-01-01

Ergonomic research on nursing work has focused primarily on the biomechanical analysis of patient handling tasks. Few studies have addressed the intensity of a full day of nursing work as measured by changes in heart rate and energy expenditure. A pilot study was conducted between August 2009 and May 2010 to examine the intensity of performing nursing assistant work in long term care settings and to assess the usefulness of heart rate monitoring as a measure of work intensity. The residents of the facilities were physically dependent adults. The settings had floor-based mechanical lifting devices available and no-lift policies that restricted workers from lifting. Eight women between the ages of 19 and 54 from two facilities participated in this study. A wearable recorder allowed unobtrusive heart rate monitoring while nursing assistants worked their usual shift. Continuous heart rate monitoring for a full shift provided an estimation of energy expenditure. The data suggest that the nursing assistants worked at a moderate level yet were within the safe work intensity level recommended by NIOSH [32]. The information provides preliminary baseline data for nursing assistants who work with physically dependent adults using floor-based lifts in a no-lift environment.

Massage therapy in post-operative rehabilitation of children and adolescents with cerebral palsy - a pilot study.

PubMed

Nilsson, Stefan; Johansson, Gunilla; Enskär, Karin; Himmelmann, Kate

2011-08-01

The purpose of this pilot study was to explore the use of massage therapy in children with cerebral palsy undergoing post-operative rehabilitation. Three participants were randomized to massage therapy and another three participants to rest. All children had undergone surgery in one or two lower limbs. Pain, wellbeing, sleep quality, heart rate and qualitative data were collected for each child. The scores of pain intensity and discomfort were low in all participants. Heart rate decreased in participants who were randomized to rest, but no change was found in the massage therapy group. The lack of decrease in heart rate in the study group of massage therapy may imply an increased sensitivity to touch in the post-operative setting. Further research with larger study populations are needed to evaluate how and when massage therapy is useful for children with cerebral palsy. Copyright © 2010 Elsevier Ltd. All rights reserved.

Central nervous systen alpha-adrenergic mechanisms and cardiovascular regulation in rats.

PubMed

Boudier, H S; Smeets, G; Brouwer, G; Van Rossum, J M

1975-02-01

Noradrenaline (NA) induced a decrease in blood pressure and heart rate when injected into specific areas in either the medulla oblongata or the hypothalamus. In the medulla the area of the nucleus tractus solitarius was specifically sensitive to NA; in the hypothalamus depressor effects were obtained only after NA injections into the anterior hypothalamic/preoptic region. The cardiovascular effects induced by NA (3-40 nmol) in these areas consisted of an immediate decrease in both arterial pressure and heart rate. Size and duration of these effects depended upon the dose of NA injected. Alpha-methylNA (5-15 nmol) induced a long lasting decrease in blood pressure and heart rate when injected into the anterior hypothalamic/preoptic region. These data are discussed in view of the existence of at least two sites within the central nervous system (CNS) from which interference with noradrenergic mechanisms can cause changes in the cardiovascular system.

Heart rate variability reactivity and new romance: Cause or consequence?

PubMed

Bailey, Laura K; Davis, Ron

2017-09-01

There are documented physiological differences between single and coupled individuals during the "honeymoon period" of nascent romantic relationships. One such difference is in autonomic reactivity, specifically heart rate variability (HRV) reactivity. This finding had previously been interpreted as evidence of a stress buffering effect of relationship formation. The present study explored among university women two competing longitudinal hypotheses conceptualizing differences in HRV reactivity as either a cause or a consequence of romantic relationship formation. Results did not support the hypothesis that HRV reactivity changes as a consequence of beginning a new romantic relationship. Instead, lower HRV reactivity predicted greater relationship formation amongst women with low BMI and higher resting HRV. The functioning of the heart therefore predicted the likelihood that an individual would find love. These interactions may be the result of differing success rates of various mating strategies for women with low and high BMI and HRV. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization and visual illustration of the consequences motion of human body for the determination of heart rate

NASA Astrophysics Data System (ADS)

Nedoma, Jan; Fajkus, Marcel; Martinek, Radek; Kepak, Stanislav; Cubik, Jakub; Vasinek, Vladimir

2017-10-01

The team of authors focused on analyzing of using fiber-optic sensor based on Fiber Bragg Grating (FBG) for the monitoring of heart rate (HR) of long-term ill patients with a minimum of physical movement load. During all experiments, test subjects were asked to simulate their natural behavior in the most accurate way (for instance, the focus was on the use of fine motor skills - not only movements of hands and arms, legs, and feet, coughing, changes in body positions, but also walking). All these external aspects are taken into account in the bellow-described results of the probe efficiency and show that it is very necessary to know the impact of these artifacts for the determine the heart rate of the human body. Final results were discussed with the senior doctor of the long-term care department.

Physiological and behavioral parameters of infants' categorization: changes in heart rate and duration of examining across trials.

PubMed

Elsner, Birgit; Pauen, Sabina; Jeschonek, Susanna

2006-11-01

This report investigates the relations between duration of examining and heart rate (HR) across several trials of an object-examination task. A total of N= 20 11-month-olds were familiarized with a sequence of 10 different exemplars from the same global category (animals or furniture) before they received an exemplar from the contrasting category at test. Consistent with previous findings, HR was lower during states of focused attention (i.e. examining) than during states of casual attention (i.e. looking) or non-looking. Over the familiarization trials, examining stayed about the same, while mean HR increased. At test, examining increased and mean HR decreased, indicating that infants focused their attention on the out-of-category object. Psychophysiological and behavioral measures of attention were systematically related over trials, suggesting that heart rate provides a suitable objective measure to study infants' categorization performance in object-examination tasks.

ACUTE CARDIOVASCULAR EFFECTS OF FIREFIGHTING AND ACTIVE COOLING DURING REHABILITATION

PubMed Central

Burgess, Jefferey L.; Duncan, Michael D.; Hu, Chengcheng; Littau, Sally R.; Caseman, Delayne; Kurzius-Spencer, Margaret; Davis-Gorman, Grace; McDonagh, Paul F.

2012-01-01

Objectives To determine the cardiovascular and hemostatic effects of fire suppression and post-exposure active cooling. Methods Forty-four firefighters were evaluated prior to and after a 12 minute live-fire drill. Next, 50 firefighters undergoing the same drill were randomized to post-fire forearm immersion in 10°C water or standard rehabilitation. Results In the first study, heart rate and core body temperature increased and serum C-reactive protein decreased but there were no significant changes in fibrinogen, sE-selectin or sL-selectin. The second study demonstrated an increase in blood coagulability, leukocyte count, factors VIII and X, cortisol and glucose, and a decrease in plasminogen and sP-selectin. Active cooling reduced mean core temperature, heart rate and leukocyte count. Conclusions Live-fire exposure increased core temperature, heart rate, coagulability and leukocyte count; all except coagulability were reduced by active cooling. PMID:23090161

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

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

Is heart rate variability associated with frequency and intensity of vasomotor symptoms among healthy perimenopausal and postmenopausal women?

PubMed

Jones, Salene M W; Guthrie, Katherine A; LaCroix, Andrea Z; Sternfeld, Barbara; Landis, Carol A; Reed, Susan D; Dunn, Andrea; Caan, Bette; Cohen, Lee S; Hunt, Julie; Newton, Katherine M

2016-02-01

Research has suggested that the autonomic nervous system (ANS) is involved in the experience of vasomotor symptoms (VMS) during menopause. We examined the relationship of VMS intensity and heart rate variability (HRV), a measure of ANS function. Women (n = 282) were recruited from three American states for a clinical trial of yoga, exercise, and omega-3 fatty acid supplements for VMS. To be eligible, women had to report at least 14 VMS per week, with some being moderate to severe. Sitting electrocardiograms were recorded for 15 min using Holter monitors at both baseline and 12-week follow-up. Time and frequency domain HRV measures were calculated. Women completed daily diary measures of VMS frequency and intensity for 2 weeks at baseline and for 1 week at the follow-up assessment 12 weeks later. Multivariable linear regression was used to assess the relationship between VMS and baseline HRV measures and to compare change in HRV with change in VMS over the 12 weeks. Baseline HRV was not associated with either VMS frequency or intensity at baseline. Change in HRV was not associated with change in VMS frequency or intensity across the follow-up. Heart rate variability (HRV) was not associated with basal VMS frequency or intensity in perimenopausal and postmenopausal women experiencing high levels of VMS. Autonomic function may be associated with the onset or presence of VMS, but not with the number or intensity of these symptoms.

Epoetin Alfa and Outcomes in Dialysis amid Regulatory and Payment Reform

PubMed Central

Liu, Jiannong; Monda, Keri L.; Gilbertson, David T.; Brookhart, M. Alan; Beaubrun, Anne C.; Winkelmayer, Wolfgang C.; Pollock, Allan; Herzog, Charles A.; Ashfaq, Akhtar; Sturmer, Til; Rothman, Kenneth J.; Bradbury, Brian D.; Collins, Allan J.

2016-01-01

Erythropoiesis-stimulating agents (ESAs) are commonly used to treat anemia in patients with CKD, including those receiving dialysis, although clinical trials have identified risks associated with ESA use. We evaluated the effects of changes in dialysis payment policies and product labeling instituted in 2011 on mortality and major cardiovascular events across the United States dialysis population in an open cohort study of patients on dialysis from January 1, 2005, through December 31, 2012, with Medicare as primary payer. We compared observed rates of death and major cardiovascular events in 2011 and 2012 with expected rates calculated on the basis of rates in 2005–2010, accounting for differences in patient characteristics and influenza virulence. An abrupt decline in erythropoietin dosing and hemoglobin concentration began in late 2010. Observed rates of all-cause mortality, cardiovascular mortality, and myocardial infarction in 2011 and 2012 were consistent with expected rates. During 2012, observed rates of stroke, venous thromboembolic disease (VTE), and heart failure were lower than expected (absolute deviation from trend per 100 patient-years [95% confidence interval]: −0.24 [−0.08 to −0.37] for stroke, −2.43 [−1.35 to −3.70] for VTE, and −0.77 [−0.28 to −1.27] for heart failure), although non–ESA-related changes in practice and Medicare payment penalties for rehospitalization may have confounded the results. This initial evidence suggests that action taken to mitigate risks associated with ESA use and changes in payment policy did not result in a relative increase in death or major cardiovascular events and may reflect improvements in stroke, VTE, and heart failure. PMID:26917691

Habituation of 10-year-old hockey players to treadmill skating.

PubMed

Lockwood, Kelly L; Frost, Gail

2007-05-01

This study assessed changes in selected physiological and kinematic variables over 6 weeks of treadmill skating in an effort to understand the process of habituation to this novel training modality. Seven male, Atom-A hockey players who were injury-free and had no previous treadmill skating experience participated in the study. Players performed four 1-min skating bouts at progressively increasing speeds, each week, for 6 weeks. One speed (10.5 km/h) was repeated weekly to allow for assessment of the habituation process. Our criteria for habituation were: a decrease in stride rate, heart rate and rating of perceived exertion, and an increase in stride length, trunk angle and vertical movement of the centre of mass, leading to a plateau, over the course of the 6-week study. Significant decreases were seen in stride rate, heart rate and ratings of perceived exertion, and significant increases were found in stride length. Some of these changes were evident after only one week of training and all were present by week 4. After 6 weeks (24 min) of exposure to treadmill skating, all participants displayed a visibly more efficient skating style.

Heart rate, salivary α-amylase activity, and cooperative behavior in previously naïve children receiving dental local anesthesia.

PubMed

Arhakis, Aristidis; Menexes, George; Coolidge, Trilby; Kalfas, Sotirios

2012-01-01

Psychosomatic indicators, such as heart rate (HR), salivary alpha amylase (sAA) activity, and behavior, can be used to determine stress. This study's aim was to assess the pattern of changes of salivary alpha amylase, heart rate, and cooperative behavior in previously naïve children receiving dental treatment under local anesthesia. Included were 30 children with no prior dental experience who needed 4 or more sessions of dental treatment involving local anesthesia. In each session, sAA, HR, and behavior were assessed before and during the application of local anesthesia and at the end of the treatment. The highest sAA value was always observed at the end of each session; overall, the value was lower in the fourth session. HR always increased during the local anesthesia, and did not vary across sessions. No significant relationship was found between child cooperation and either sAA or HR. In this sample, child cooperation may not be an accurate indicator of stress. Based on salivary alpha amylase activity changes, dental treatment involving local anesthesia in naïve children appeared to be less stressful after 3 sessions.

Changes in cardiac output and tibial artery flow during and after progressive LBNP

NASA Technical Reports Server (NTRS)

1980-01-01

A 3.0 MHz Pulsed Doppler velocity meter (PD) was used to determine blood velocities in the ascending aorta from the suprasternal notch before, during and after progressive 5 min stages of lower body negative pressure (LBNP) in 7 subjects. Changes in stroke volume were calculated from the systolic velocity integrals. A unique 20 MHz PD was used to estimate bloodflow in the posterior tibial artery. With -20 torr mean stroke volume fell 11% and then continued to decline by 48% before LBNP was terminated. Mean tibial flow fell progressively with LBNP stress, due to an increase in reverse flow component and a reduction in peak forward flow and diameter. Stroke volume increased and heart rate fell dramatically during the first 15 sec of recovery. The LBNP was terminated early in 2 subjects because of vasovagal symptons (V). During V the stroke volume rose 86% which more than compensated for the drop in heart rate. This implies that V is accompanied by a paradoxical increase in venous return and that the reduction in HR is the primary cardiovascular event. During the first 15 sec of recovery these 2 subjects had a distinctive marked rise to heart rate reminiscent of the Bainbridge reflex.

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

PubMed

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

2008-02-01

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

Analyzing Sensor-Based Time Series Data to Track Changes in Physical Activity during Inpatient Rehabilitation.

PubMed

Sprint, Gina; Cook, Diane; Weeks, Douglas; Dahmen, Jordana; La Fleur, Alyssa

2017-09-27

Time series data collected from sensors can be analyzed to monitor changes in physical activity as an individual makes a substantial lifestyle change, such as recovering from an injury or illness. In an inpatient rehabilitation setting, approaches to detect and explain changes in longitudinal physical activity data collected from wearable sensors can provide value as a monitoring, research, and motivating tool. We adapt and expand our Physical Activity Change Detection (PACD) approach to analyze changes in patient activity in such a setting. We use Fitbit Charge Heart Rate devices with two separate populations to continuously record data to evaluate PACD, nine participants in a hospitalized inpatient rehabilitation group and eight in a healthy control group. We apply PACD to minute-by-minute Fitbit data to quantify changes within and between the groups. The inpatient rehabilitation group exhibited greater variability in change throughout inpatient rehabilitation for both step count and heart rate, with the greatest change occurring at the end of the inpatient hospital stay, which exceeded day-to-day changes of the control group. Our additions to PACD support effective change analysis of wearable sensor data collected in an inpatient rehabilitation setting and provide insight to patients, clinicians, and researchers.

Validation of 18F-fluoro-4-thia-palmitate as a PET probe for myocardial fatty acid oxidation: effects of hypoxia and composition of exogenous fatty acids.

PubMed

DeGrado, Timothy R; Kitapci, Mehmet T; Wang, Shuyan; Ying, Jun; Lopaschuk, Gary D

2006-01-01

Fatty acid oxidation (FAO) is the predominant energy-producing pathway in the healthy heart. Abnormalities in FAO are associated with many ischemic and nonischemic disease states. The aim of the present study was to further validate 16-[(18)F]-fluoro-4-thia-palmitate ((18)F-FTP) as a metabolically trapped FAO probe in the isolated perfused rat heart model by examining both the effects of hypoxia and the effects of changes in exogenous fatty acid availability. Hearts were excised from Sprague-Dawley rats and perfused in the Langendorff mode with Krebs-Henseleit solution under the following conditions: palmitate at 0.4 mmol/L with 95% oxygen, palmitate at 0.4 mmol/L with 35% oxygen, palmitate at 0.2 mmol/L plus oleate at 0.2 mmol/L with 95% oxygen, and palmitate at 0.2 mmol/L plus oleate at 0.2 mmol/L with 35% oxygen. Hearts were paced at 270 beats per minute, and the rate of left ventricular pressure change (LV dP/dt) was monitored. (18)F-FTP in the perfusion medium was administered for 20 min, and this step was followed by a 20-min washout period without tracer in the perfusion medium. (18)F kinetics in the whole heart were monitored externally, and the time-activity curves were analyzed to determine the fractional trapping rate for (18)F-FTP (FTR(FTP)). A "lumped constant" (LC) was defined as the ratio of FTR(FTP) to the fractional rate of oxidation of fatty acid in the perfusion medium. The kinetic data for (18)F-FTP demonstrated metabolic trapping of (18)F radioactivity that was insensitive to changes in the mixture of fatty acids in the perfusion medium but that was sensitive to the inhibition of mitochondrial FAO by hypoxia. LV dP/dt was reduced 47%-67% in hypoxic hearts relative to hearts with normal oxygenation (controls). FAO rates for palmitate and oleate were similar in group 3 (palmitate alone) and group 4 (palmitate and oleate). FAO was decreased 70%-76% with hypoxia, whereas FTR(FTP) was reduced 86%-88%, demonstrating hypersensitivity of a change in (18)F-FTP retention to FAO inhibition by oxygen deprivation. The (18)F-FTP LC was approximately 2 in myocardium with normal oxygenation and fell to 1.0-1.2 in hypoxic myocardium. The results confirm (18)F-FTP to be a metabolically trapped palmitate analog that is capable of indicating rates of myocardial oxidation of exogenous long-chain fatty acids. The heterogeneous nature of fatty acids in plasma does not alter the quantitative analysis of (18)F-FTP kinetics. However, the decreased LC value in hypoxic myocardium suggests the need to develop an understanding of the relationship of (18)F-FTP processing to natural fatty acids at key limiting transport and metabolism processes, analogous to previous studies examining the LC values for radiolabeled deoxyglucose tracers used to estimate the glucose metabolic rate.

Randomized controlled study of the safety and efficacy of nitrous oxide-sedated endoscopic ultrasound-guided fine needle aspiration for digestive tract diseases.

PubMed

Wang, Cai-Xia; Wang, Jian; Chen, Yuan-Yuan; Wang, Jia-Ni; Yu, Xin; Yang, Feng; Sun, Si-Yu

2016-12-14

To evaluate the efficacy and safety of nitrous oxide-sedated endoscopic ultrasound-guided fine needle aspiration. Enrolled patients were divided randomly into an experimental group (inhalation of nitrous oxide) and a control group (inhalation of pure oxygen) and heart rate, blood oxygen saturation, blood pressure, electrocardiogram (ECG) changes, and the occurrence of complications were monitored and recorded. All patients and physicians completed satisfaction questionnaires about the examination and scored the process using a visual analog scale. There was no significant difference in heart rate, blood oxygen saturation, blood pressure, ECG changes, or complication rate between the two groups of patients ( P > 0.05). However, patient and physician satisfaction were both significantly higher in the nitrous oxide compared with the control group ( P < 0.05). Nitrous oxide-sedation is a safe and effective option for patients undergoing endoscopic ultrasound-guided fine needle aspiration.

Cardiovascular changes in unanesthetized and ketamine-anesthetized Sprague-Dawley rats exposed to 2. 8-GHz radiofrequency radiation

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

Jauchem, J.R.; Frei, M.R.

1991-01-01

Sprague-Dawley rats were exposed to 2.8-GHz radiofrequency radiation, first while unanesthetized and then while anesthetized with ketamine (150 mg/kg.I.M.). Irradiation at a power density of 60 mW/cm2 (whole-body average specific absorption rate of approximately 14 W/kg) was conducted for sufficient duration to increase colonic temperature from 38.5 to 39.5 degrees C. The time required for the temperature increase was significantly longer in the anesthetized state. During irradiation, heart rate increased significantly both with and without anesthesia, while mean arterial blood pressure increased only when the rats were unanesthetized. The heart rate increase in the anesthetized state contrasts with a lackmore » of change in a previous study of Fischer rats. This difference between anesthetized Sprague-Dawley and Fischer rats should be considered when comparing cardiovascular data obtained from these two strains of rats.« less

Response and adaptation of Beagle dogs to hypergravity

NASA Technical Reports Server (NTRS)

Oyama, J.

1975-01-01

Eight male Beagle dogs, five months old, were centrifuged continuously for three months at progressively increasing loads. Heart rate and deep body temperature were monitored continuously by implant biotelemetry. Initially, centrifuged dogs showed transient decreases in heart rate and body temperature along with changes in their diurnal rhythm patterns. Compared with normal gravity controls, exposed dogs showed a slower growth rate and a reduced amount of body fat. Blood protein, total lipids, cholesterol, calcium, packed cell volume, red blood cell count, and hemoglobin were also decreased significantly. Absolute weights of the leg bones of centrifuged dogs were significantly greater than controls. Photon absorptiometry revealed significant density increases in selective regions of the femur and humerus of centrifuged dogs. In spite of the various changes noted, results from this and other studies affirm the view that dogs can tolerate and adapt to sustained loads as high as 2.5 g without serious impairment of their body structure and function.

Physiological responses of mules on prolonged exposure to high altitude (3 650 m)

NASA Astrophysics Data System (ADS)

Riar, S. S.; Shankar Bhat, K.; Sen Gupta, J.

1982-06-01

Eight healthy male animals were inducted and kept for 2 1/2 years at 3 650 m altitude and subjected to normal work schedules. Physiological measurements viz. heart rate, blood pressure, minute ventilation, oxygen consumption, respiration rate, hemoglobin, packed cell haematocrit volume and eosinophil count were made on these animals at periodic intervals. On acute induction to an altitude of 3 650 m these animals demonstrated a sudden increase in tidal volume, a decrease in Rf and no change in VE, suggesting a decreased dead space/tidal volume ratio at altitude. However, all these changes stabilised within 3 weeks but on prolongation of stay, the physical state of these animals was adversely affected. The respiratory adjustments occurring on return to sea level appear to be a response to thermal stress. The initial increase in heart rate and blood pressure stabilised by the 2nd week.

Electrophysiological effects of the aqueous extract of Averrhoa carambola L. leaves on the guinea pig heart.

PubMed

Vasconcelos, C M L; Araújo, M S; Conde-Garcia, E A

2006-07-01

This work aims to describe some electrophysiological changes promoted by the aqueous extract (AEx) from Averrhoa carambola leaves in guinea pig heart. The experiments were carried out on isolated heart or on right atrium-ventricle preparations. In 6 hearts, the extract induced many kinds of atrioventricular blocks (1st, 2nd, and 3rd degrees); increased the QT interval from 229+/-23 to 264+/-19 ms; increased the QRS complex duration from 27+/-3.1 to 59+/-11 ms, and depressed the cardiac rate from 136+/-17 to 89+/-14b pm. Furthermore, it decreased the conduction velocity of atrial impulse (17+/-3%); reduced the intraventricular pressure (86+/-6%), and increased the conduction time between the right atrium and the His bundle (27+/-6.5%). The conduction time from the His bundle to the right ventricle was not altered. Atropine sulfate did not change either the electrocardiographic parameters or the intraventricular pressure effects promoted by the A. carambola AEx. Based on these results, the popular use of such extracts should be avoided because it can promote electrical and mechanical changes in the normal heart.

A mobile system for assessment of physiological response to posture transitions.

PubMed

Jovanov, Emil; Milosevic, Mladen; Milenković, Aleksandar

2013-01-01

Posture changes initiate a dynamic physiological response that can be used as an indicator of the overall health status. We introduce an inconspicuous mobile wellness monitoring system (imWell) that continuously assesses the dynamic physiological response to posture transitions during activities of daily living. imWell utilizes a Zephyr BioHarness 3 physiological monitor that continually reports heart activity and physical activity via Bluetooth to a personal device (e.g. smartphone). The personal device processes the reported activity data in real-time to recognize posture transitions from the accelerometer data and to characterize dynamic heart response to posture changes. It annotates, logs, and uploads the heart activity data to our mHealth server. In this paper we present algorithms for detection of posture transitions and heart activity characterization during a sit-to-stand transition. The proposed system was tested on seven healthy subjects performing a predefined protocol. The total average and standard deviation for sit-to-stand transition time is 2.7 ± 0.69 s, resulting in the change of heart rate of 27.36 ± 9.30 bpm (from 63.3 ± 9.02 bpm to 90.66 ± 10.09 bpm).

A Nationwide Assessment of the Association of Smoking Bans and Cigarette Taxes With Hospitalizations for Acute Myocardial Infarction, Heart Failure, and Pneumonia

PubMed Central

Ho, Vivian; Ross, Joseph S.; Steiner, Claudia A.; Mandawat, Aditya; Short, Marah; Ku-Goto, Meei-Hsiang; Krumholz, Harlan M.

2016-01-01

Multiple studies claim that public place smoking bans are associated with reductions in smoking-related hospitalization rates. No national study using complete hospitalization counts by area that accounts for contemporaneous controls including state cigarette taxes has been conducted. We examine the association between county-level smoking-related hospitalization rates and comprehensive smoking bans in 28 states from 2001 to 2008. Differences-in-differences analysis measures changes in hospitalization rates before versus after introducing bans in bars, restaurants, and workplaces, controlling for cigarette taxes, adjusting for local health and provider characteristics. Smoking bans were not associated with acute myocardial infarction or heart failure hospitalizations, but lowered pneumonia hospitalization rates for persons ages 60 to 74 years. Higher cigarette taxes were associated with lower heart failure hospitalizations for all ages and fewer pneumonia hospitalizations for adults aged 60 to 74. Previous studies may have overestimated the relation between smoking bans and hospitalizations and underestimated the effects of cigarette taxes. PMID:27624634

A Nationwide Assessment of the Association of Smoking Bans and Cigarette Taxes With Hospitalizations for Acute Myocardial Infarction, Heart Failure, and Pneumonia.

PubMed

Ho, Vivian; Ross, Joseph S; Steiner, Claudia A; Mandawat, Aditya; Short, Marah; Ku-Goto, Meei-Hsiang; Krumholz, Harlan M

2017-12-01

Multiple studies claim that public place smoking bans are associated with reductions in smoking-related hospitalization rates. No national study using complete hospitalization counts by area that accounts for contemporaneous controls including state cigarette taxes has been conducted. We examine the association between county-level smoking-related hospitalization rates and comprehensive smoking bans in 28 states from 2001 to 2008. Differences-in-differences analysis measures changes in hospitalization rates before versus after introducing bans in bars, restaurants, and workplaces, controlling for cigarette taxes, adjusting for local health and provider characteristics. Smoking bans were not associated with acute myocardial infarction or heart failure hospitalizations, but lowered pneumonia hospitalization rates for persons ages 60 to 74 years. Higher cigarette taxes were associated with lower heart failure hospitalizations for all ages and fewer pneumonia hospitalizations for adults aged 60 to 74. Previous studies may have overestimated the relation between smoking bans and hospitalizations and underestimated the effects of cigarette taxes.

Hydroxychloroquine reduces heart rate by modulating the hyperpolarization-activated current If: Novel electrophysiological insights and therapeutic potential

PubMed Central

Capel, Rebecca A.; Herring, Neil; Kalla, Manish; Yavari, Arash; Mirams, Gary R.; Douglas, Gillian; Bub, Gil; Channon, Keith; Paterson, David J.; Terrar, Derek A.; Burton, Rebecca-Ann B.

2015-01-01

Background Bradycardic agents are of interest for the treatment of ischemic heart disease and heart failure, as heart rate is an important determinant of myocardial oxygen consumption. Objectives The purpose of this study was to investigate the propensity of hydroxychloroquine (HCQ) to cause bradycardia. Methods We assessed the effects of HCQ on (1) cardiac beating rate in vitro (mice); (2) the “funny” current (If) in isolated guinea pig sinoatrial node (SAN) myocytes (1, 3, 10 µM); (3) heart rate and blood pressure in vivo by acute bolus injection (rat, dose range 1–30 mg/kg), (4) blood pressure and ventricular function during feeding (mouse, 100 mg/kg/d for 2 wk, tail cuff plethysmography, anesthetized echocardiography). Results In mouse atria, spontaneous beating rate was significantly (P < .05) reduced (by 9% ± 3% and 15% ± 2% at 3 and 10 µM HCQ, n = 7). In guinea pig isolated SAN cells, HCQ conferred a significant reduction in spontaneous action potential firing rate (17% ± 6%, 1 μM dose) and a dose-dependent reduction in If (13% ± 3% at 1 µM; 19% ± 2% at 3 µM). Effects were also observed on L-type calcium ion current (ICaL) (12% ± 4% reduction) and rapid delayed rectifier potassium current (IKr) (35% ± 4%) at 3 µM. Intravenous HCQ decreased heart rate in anesthetized rats (14.3% ± 1.1% at 15mg/kg; n = 6) without significantly reducing mean arterial blood pressure. In vivo feeding studies in mice showed no significant change in systolic blood pressure nor left ventricular function. Conclusions We have shown that HCQ acts as a bradycardic agent in SAN cells, in atrial preparations, and in vivo. HCQ slows the rate of spontaneous action potential firing in the SAN through multichannel inhibition, including that of If. PMID:26025323

High-Intensity Interval Training in Patients With Heart Failure With Reduced Ejection Fraction

PubMed Central

Halle, Martin; Conraads, Viviane; Støylen, Asbjørn; Dalen, Håvard; Delagardelle, Charles; Larsen, Alf-Inge; Hole, Torstein; Mezzani, Alessandro; Van Craenenbroeck, Emeline M.; Videm, Vibeke; Beckers, Paul; Christle, Jeffrey W.; Winzer, Ephraim; Mangner, Norman; Woitek, Felix; Höllriegel, Robert; Pressler, Axel; Monk-Hansen, Tea; Snoer, Martin; Feiereisen, Patrick; Valborgland, Torstein; Kjekshus, John; Hambrecht, Rainer; Gielen, Stephan; Karlsen, Trine; Prescott, Eva; Linke, Axel

2017-01-01

Background: Small studies have suggested that high-intensity interval training (HIIT) is superior to moderate continuous training (MCT) in reversing cardiac remodeling and increasing aerobic capacity in patients with heart failure with reduced ejection fraction. The present multicenter trial compared 12 weeks of supervised interventions of HIIT, MCT, or a recommendation of regular exercise (RRE). Methods: Two hundred sixty-one patients with left ventricular ejection fraction ≤35% and New York Heart Association class II to III were randomly assigned to HIIT at 90% to 95% of maximal heart rate, MCT at 60% to 70% of maximal heart rate, or RRE. Thereafter, patients were encouraged to continue exercising on their own. Clinical assessments were performed at baseline, after the intervention, and at follow-up after 52 weeks. Primary end point was a between-group comparison of change in left ventricular end-diastolic diameter from baseline to 12 weeks. Results: Groups did not differ in age (median, 60 years), sex (19% women), ischemic pathogenesis (59%), or medication. Change in left ventricular end-diastolic diameter from baseline to 12 weeks was not different between HIIT and MCT (P=0.45); left ventricular end-diastolic diameter changes compared with RRE were −2.8 mm (−5.2 to −0.4 mm; P=0.02) in HIIT and −1.2 mm (−3.6 to 1.2 mm; P=0.34) in MCT. There was also no difference between HIIT and MCT in peak oxygen uptake (P=0.70), but both were superior to RRE. However, none of these changes was maintained at follow-up after 52 weeks. Serious adverse events were not statistically different during supervised intervention or at follow-up at 52 weeks (HIIT, 39%; MCT, 25%; RRE, 34%; P=0.16). Training records showed that 51% of patients exercised below prescribed target during supervised HIIT and 80% above target in MCT. Conclusions: HIIT was not superior to MCT in changing left ventricular remodeling or aerobic capacity, and its feasibility remains unresolved in patients with heart failure. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00917046. PMID:28082387

High-Intensity Interval Training in Patients With Heart Failure With Reduced Ejection Fraction.

PubMed

Ellingsen, Øyvind; Halle, Martin; Conraads, Viviane; Støylen, Asbjørn; Dalen, Håvard; Delagardelle, Charles; Larsen, Alf-Inge; Hole, Torstein; Mezzani, Alessandro; Van Craenenbroeck, Emeline M; Videm, Vibeke; Beckers, Paul; Christle, Jeffrey W; Winzer, Ephraim; Mangner, Norman; Woitek, Felix; Höllriegel, Robert; Pressler, Axel; Monk-Hansen, Tea; Snoer, Martin; Feiereisen, Patrick; Valborgland, Torstein; Kjekshus, John; Hambrecht, Rainer; Gielen, Stephan; Karlsen, Trine; Prescott, Eva; Linke, Axel

2017-02-28

Small studies have suggested that high-intensity interval training (HIIT) is superior to moderate continuous training (MCT) in reversing cardiac remodeling and increasing aerobic capacity in patients with heart failure with reduced ejection fraction. The present multicenter trial compared 12 weeks of supervised interventions of HIIT, MCT, or a recommendation of regular exercise (RRE). Two hundred sixty-one patients with left ventricular ejection fraction ≤35% and New York Heart Association class II to III were randomly assigned to HIIT at 90% to 95% of maximal heart rate, MCT at 60% to 70% of maximal heart rate, or RRE. Thereafter, patients were encouraged to continue exercising on their own. Clinical assessments were performed at baseline, after the intervention, and at follow-up after 52 weeks. Primary end point was a between-group comparison of change in left ventricular end-diastolic diameter from baseline to 12 weeks. Groups did not differ in age (median, 60 years), sex (19% women), ischemic pathogenesis (59%), or medication. Change in left ventricular end-diastolic diameter from baseline to 12 weeks was not different between HIIT and MCT ( P =0.45); left ventricular end-diastolic diameter changes compared with RRE were -2.8 mm (-5.2 to -0.4 mm; P =0.02) in HIIT and -1.2 mm (-3.6 to 1.2 mm; P =0.34) in MCT. There was also no difference between HIIT and MCT in peak oxygen uptake ( P =0.70), but both were superior to RRE. However, none of these changes was maintained at follow-up after 52 weeks. Serious adverse events were not statistically different during supervised intervention or at follow-up at 52 weeks (HIIT, 39%; MCT, 25%; RRE, 34%; P =0.16). Training records showed that 51% of patients exercised below prescribed target during supervised HIIT and 80% above target in MCT. HIIT was not superior to MCT in changing left ventricular remodeling or aerobic capacity, and its feasibility remains unresolved in patients with heart failure. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00917046. © 2017 The Authors.

Optically Remote Noncontact Heart Rates Sensing Technique

NASA Astrophysics Data System (ADS)

Thongkongoum, W.; Boonduang, S.; Limsuwan, P.

2017-09-01

Heart rate monitoring via optically remote noncontact technique was reported in this research. A green laser (5 mW, 532±10 nm) was projected onto the left carotid artery. The reflected laser light on the screen carried the deviation of the interference patterns. The interference patterns were recorded by the digital camera. The recorded videos of the interference patterns were frame by frame analysed by 2 standard digital image processing (DIP) techniques, block matching (BM) and optical flow (OF) techniques. The region of interest (ROI) pixels within the interference patterns were analysed for periodically changes of the interference patterns due to the heart pumping action. Both results of BM and OF techniques were compared with the reference medical heart rate monitoring device by which a contact measurement using pulse transit technique. The results obtained from BM technique was 74.67 bpm (beats per minute) and OF technique was 75.95 bpm. Those results when compared with the reference value of 75.43±1 bpm, the errors were found to be 1.01% and 0.69%, respectively.

Ivabradine in acute coronary syndromes: Protection beyond heart rate lowering.

PubMed

Niccoli, Giampaolo; Borovac, Josip Anđelo; Vetrugno, Vincenzo; Camici, Paolo G; Crea, Filippo

2017-06-01

Ivabradine is a heart rate reducing agent that exhibits anti-ischemic effects through the inhibition of funny electrical current in the sinus node resulting in heart rate reduction, thus enabling longer diastolic perfusion time, and reduced myocardial oxygen consumption without detrimental changes in arterial blood pressure, coronary vasomotion, and ventricular contractility. The current guideline-based clinical use of Ivabradine is reserved for patients with stable angina pectoris who cannot tolerate or whose symptoms are inadequately controlled with beta blockers. In patients with chronic heart failure and reduced ejection fraction, Ivabradine has demonstrated beneficial effects in improving clinical outcomes when added to conventional therapy. However, the role of Ivabradine in acute coronary syndromes has not been established. Based on the results from some relevant preclinical studies and a limited amount of clinical data that were reported recently, the role of Ivabradine in acute ischemic events warrants further investigation. The aim of this review is to provide an overview of the available literature on the potential role of Ivabradine in the clinical context of acute coronary syndromes. Copyright © 2017 Elsevier B.V. All rights reserved.

Maturation of heart rate and blood pressure variability during sleep in term-born infants.

PubMed

Yiallourou, Stephanie R; Sands, Scott A; Walker, Adrian M; Horne, Rosemary S C

2012-02-01

Abnormal blood pressure control is implicated in the sudden infant death syndrome (SIDS). However, no data exist on normal development of blood pressure control during infancy. This study assessed maturation of autonomic control of blood pressure and heart rate during sleep within the first 6 months of life. Term infants (n = 31) were studied longitudinally at 2-4 weeks, 2-3 months, and 5-6 months postnatal age. Infants underwent daytime polysomnography at each age studied. Blood pressure and heart rate were recorded during quiet (QS) and active (AS) sleep in undisturbed baseline and head-up tilt conditions. Autonomic control was assessed using spectral indices of blood pressure and heart rate variability (BPV and HRV) in ranges of low frequency (LF, reflecting sympathetic + parasympathetic activity) and high frequency (HF, parasympathetic activity), total power (LF+HF), and LF/HF ratio (sympathovagal balance). With increasing postnatal age and predominantly during QS, HRV-LF, HRV-HF, and HRV total power increased, while HRV-LF/HF decreased. BPV-LF/HF also decreased with postnatal age. All changes were evident in both baseline and head-up tilt conditions. BPV-LF and BPV total power during tilts were markedly reduced in QS versus AS at each age. In sleeping infants, sympathetic vascular modulation of the circulation decreases with age, while parasympathetic control of heart rate is strengthened. These normative data will aid in the early identification of conditions where autonomic function is impaired, such as in SIDS.

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…

Cerebrospinal fluid hypocretin (orexin) levels are elevated by play but are not raised by exercise and its associated heart rate, blood pressure, respiration or body temperature changes.

PubMed

Wu, M-F; Nienhuis, R; Maidment, N; Lam, H A; Siegel, J M

2011-11-07

Hypocretin (Hcrt) has been implicated in the control of motor activity and in respiration and cardiovascular changes. Loss of Hcrt in narcolepsy is linked to sleepiness and to cataplexy, a sudden loss of muscle tone which is triggered by sudden strong emotions. In the current study we have compared the effects of treadmill running, to yard play on cerebrospinal fluid (CSF) Hcrt level in normal dogs. We find that treadmill locomotion, at a wide range of speeds, does not increase Hcrt level beyond baseline, whereas yard play produces a substantial increase in Hcrt, even though both activities produce comparable increases in heart rate, respiration and body temperature. We conclude that motor and cardiovascular changes are not sufficient to elevate CSF levels of Hcrt and we hypothesize that the emotional aspects of yard play account for the observed increase in Hcrt.

Heart rate variability changes in business process outsourcing employees working in shifts.

PubMed

Kunikullaya, Kirthana U; Kirthi, Suresh K; Venkatesh, D; Goturu, Jaisri

2010-10-31

Irregular and poor quality sleep is common in business process outsourcing (BPO) employees due to continuous shift working. The influence of this on the cardiac autonomic activity was investigated by the spectral analysis of heart rate variability (HRV). 36 night shift BPO employees (working from 22:00 to 06:00h) and 36 age and sex matched day shift BPO employees (working from 08:00 to 16:00h) were recruited for the study. Five minute electrocardiogram (ECG) was recorded in all the subjects. Heart rate variability was analyzed by fast Fourier transformation using RMS Vagus HRV software. The results were analyzed using Mann Whitney U test, Student t-test, Wilcoxon signed rank test and were expressed as mean ± SD. Sleepiness was significantly higher among night shift workers as measured by Epworth Sleepiness Scale (p<0.001). Night shift BPO employees were found to have a trend towards lower values of vagal parameters - HF power (ms(2)), and higher values of sympathovagal parameters like LF Power (ms(2)) and the LF/HF power (%) suggesting decreased vagal activity and sympathetic over activity, when compared to day shift employees. However, HRV parameters did not vary significantly between the day shift employees and night shift workers baseline values, and also within the night shift group. Night shift working increased the heart rate and shifted the sympathovagal balance towards sympathetic dominance and decreased vagal parameters of HRV. This is an indicator of unfavorable change in the myocardial system, and thus shows increased risk of cardiovascular disease among the night shift employees.

Role of the carotid body chemoreceptors in baroreflex control of blood pressure during hypoglycaemia in humans

PubMed Central

Limberg, Jacqueline K; Taylor, Jennifer L; Dube, Simmi; Basu, Rita; Basu, Ananda; Joyner, Michael J; Wehrwein, Erica A

2014-01-01

Activation of the carotid body chemoreceptors with hypoxia alters baroreceptor mediated responses. We aimed to examine whether this relationship can be translated to other chemoreceptor stimuli (i.e. hypoglycaemia) and hypothesized: 1) activation of the carotid body chemoreceptors with hypoglycaemia would reduce spontaneous cardiac baroreflex sensitivity (sCBRS) in healthy humans and, 2) desensitization of the carotid chemoreceptors with hyperoxia would restore sCBRS to baseline levels during hypoglycaemia. Ten young healthy adults completed two 180-min hyperinsulinaemic (2 mU.kg FFM−1.min−1), hypoglycaemic (~3.2 µmol.mL−1) clamps, separated by at least one week and randomized to normoxia (PaO2 122±10 mmHg) or hyperoxia (PaO2 424±123 mmHg; to blunt activation of the carotid body glomus cells). Changes in heart rate, blood pressure, plasma catecholamines, heart rate variability (HRV), and sCBRS were assessed. During hypoglycaemia, HRV and sCBRS were reduced (p<0.05) and the baroreflex working range was shifted to higher heart rates. When hyperoxia was superimposed on hypoglycaemia, there was a greater reduction in blood pressure and a blunted rise in heart rate when compared to normoxic conditions (p<0.05); however, there was no detectable effect of hyperoxia on sCBRS or HRV during hypoglycaemia (p>0.05). In summary, hypoglycaemia-mediated changes in HRV and sCBRS cannot be exclusively attributed to the carotid chemoreceptors; however, the chemoreceptors appear to play a role in resetting the baroreflex working range during hypoglycaemia. PMID:24414173

Heart rate monitoring mobile applications.

PubMed

Chaudhry, Beenish M

2016-01-01

Total number of times a heart beats in a minute is known as the heart rate. Traditionally, heart rate was measured using clunky gadgets but these days it can be measured with a smartphone's camera. This can help you measure your heart rate anywhere and at anytime, especially during workouts so you can adjust your workout intensity to achieve maximum health benefits. With simple and easy to use mobile app, 'Unique Heart Rate Monitor', you can also maintain your heart rate history for personal reflection and sharing with a provider.

Influence of body mass loss on changes in heart rate during exercise in the heat: a systematic review.

PubMed

Adams, William M; Ferraro, Elizabeth M; Huggins, Robert A; Casa, Douglas J

2014-08-01

The purpose of this review was to compare the changes in heart rate (HR) for every 1% change in body mass loss (ΔBML) in individuals while exercising in the heat. PubMed, SPORTDiscus, ERIC, CINAHL, and Scopus were searched from the earliest entry to February 2013 using the search terms dehydration, heart rate, and exercise in various combinations. Original research articles that met the following criteria were included: (a) valid measure of HR, (b) exercise in the heat (>26.5° C [79.7 °F]), (c) the level of dehydration reached at least 2%, (d) a between-group comparison (a euhydrated group or a graded dehydration protocol) was evident, and (e) for rehydration protocols, only oral rehydration was considered for inclusion. Twenty articles were included in the final analysis. Mean values and SDs for HR and percentage of body mass loss immediately after exercise were used for this review. The mean change in HR for every 1% ΔBML was 3 b·min-1. In trials where subjects arrived euhydrated and hypohydrated, the mean change in HR for every 1% ΔBML was 3 and 3 b·min-1, respectively. Fixed intensity and variable intensity trials exhibited a mean HR change of 4 and 1 b·min-1, respectively. Exercising in the heat while hypohydrated (≥2%) resulted in an increased HR after exercise. This increase in HR for every 1% ΔBML exacerbates cardiovascular strain in exercising individuals, thus causing decrements in performance. It should be encouraged that individuals should maintain an adequate level of hydration to maximize performance, especially in the heat.

Effect of alectinib on cardiac electrophysiology: results from intensive electrocardiogram monitoring from the pivotal phase II NP28761 and NP28673 studies.

PubMed

Morcos, Peter N; Bogman, Katrijn; Hubeaux, Stanislas; Sturm-Pellanda, Carolina; Ruf, Thorsten; Bordogna, Walter; Golding, Sophie; Zeaiter, Ali; Abt, Markus; Balas, Bogdana

2017-03-01

Alectinib, a central nervous system (CNS)-active ALK inhibitor, has demonstrated efficacy and safety in ALK+ non-small-cell lung cancer that has progressed following crizotinib treatment. Other ALK inhibitors have shown concentration-dependent QTc prolongation and treatment-related bradycardia. Therefore, this analysis evaluated alectinib safety in terms of electrophysiologic parameters. Intensive triplicate centrally read electrocardiogram (ECG) and matched pharmacokinetic data were collected across two alectinib single-arm trials. Analysis of QTcF included central tendency analysis [mean changes from baseline with one-sided upper 95% confidence intervals (CIs)], categorical analyses, and relationship between change in QTcF and alectinib plasma concentrations. Alectinib effects on other ECG parameters (heart rate, PR interval and QRS duration) were also evaluated. Alectinib did not cause a clinically relevant change in QTcF. The maximum mean QTcF change from baseline was 5.3 ms observed pre-dose at week 2. The upper one-sided 95% CI was <10 ms at all time points. There was no relevant relationship between change in QTcF and alectinib plasma concentrations. Alectinib treatment resulted in a generally asymptomatic exposure-dependent decrease in mean heart rate of ~11 to 13 beats per minute at week 2. No clinically relevant effects were seen on other ECG parameters. Approximately 5% of patients reported cardiac adverse events of bradycardia or sinus bradycardia; however, these were all grade 1-2. Alectinib does not prolong the QTc interval or cause changes in cardiac function to a clinically relevant extent, with the exception of a decrease in heart rate which was generally asymptomatic.

Cardiovascular effects of intraosseous injections of 2 percent lidocaine with 1:100,000 epinephrine and 3 percent mepivacaine.

PubMed

Replogle, K; Reader, A; Nist, R; Beck, M; Weaver, J; Meyers, W J

1999-05-01

Because a number of patients have reported an increase in heart rate with the intraosseous, or i.o., injection, it is important to evaluate changes in the cardiovascular system with this injection technique. The purpose of this study was to determine the cardiovascular effects of an i.o. injection of 2 percent lidocaine with 1:100,000 epinephrine and 3 percent mepivacaine. With the use of a repeated-measures design, the authors randomly assigned 42 subjects to receive i.o. injections of 1.8 milliliters of 2 percent lidocaine with 1:100,000 epinephrine or 1.8 mL of 3 percent mepivacaine in a double-blinded manner at two appointments. At each appointment the authors monitored electrocardiographic findings, cardiac rate, systolic and diastolic blood pressure, and mean arterial pressure before, during and after administration of anesthetic solutions. With the 2 percent lidocaine with 1:100,000 epinephrine solution, 28 (67 percent) of 42 subjects experienced an increase in heart rate that might be attributed to the effect of the epinephrine. In 22 (79 percent) of these subjects, the heart rate returned to within 5 beats of baseline values within four minutes after solution deposition. The authors found no significant increase in heart rate in subjects receiving the 3 percent mepivacaine. No significant differences (P > .05) were found in mean diastolic, mean systolic or mean arterial blood pressure values between the subjects receiving 2 percent lidocaine with 1:100,000 epinephrine and those receiving 3 percent mepivacaine. The majority of subjects receiving the i.o. injection of the 2 percent lidocaine-epinephrine solution experienced a transient increase in heart rate. No significant increase in heart rate was seen with the i.o. injection of 3 percent mepivacaine. While patients would likely notice the heart rate increase with the lidocaine-epinephrine solution, it would not be clinically significant in most healthy patients. In patients whose medical condition, drug therapies or epinephrine sensitivity suggests caution, 3 percent mepivacaine is a good alternative for i.o. injections.

TRPA1 mediates changes in heart rate variability and cardiac ...

EPA Pesticide Factsheets

Short-term exposure to ambient air pollution is linked with adverse cardiovascular effects. While previous research focused primarily on particulate matter-induced responses, gaseous air pollutants also contribute to cause short-term cardiovascular effects. Mechanisms underlying such effects have not been adequately described; however, the immediate nature of the response suggests involvement of irritant neural activation and downstream autonomic dysfunction. Thus, this study examines the role of TRPA1, an irritant sensory receptor found in the airways, in the cardiac response of mice to acrolein and ozone. Conscious unrestrained wild-type C57BL/6 (WT) and TRPA1 knockout (KO) mice implanted with radiotelemeters were exposed once to 3ppm acrolein, 0.3ppm ozone, or filtered air. Heart rate (HR) and electrocardiogram (ECG) were recorded continuously before, during and after exposure. Analysis of ECG morphology, incidence of arrhythmia and heart rate variability (HRV) were performed. Cardiac mechanical function was assessed using a Langendorff perfusion preparation 24h post-exposure. Acrolein exposure increased HRV independent of HR, as well as incidence of arrhythmia. Acrolein also increased left ventricular developed pressure in WT mice at 24h post-exposure. Ozone did not produce any changes in cardiac function. Neither gas produced ECG effects, changes in HRV, arrhythmogenesis, or mechanical function in KO mice. These data demonstrate that a single exposure to ac

The effects of elevated water temperature on native juvenile mussels: implications for climate change

USGS Publications Warehouse

Ganser, Alissa M.; Newton, Teresa J.; Haro, Roger J.

2013-01-01

Native freshwater mussels are a diverse but imperiled fauna and may be especially sensitive to increasing water temperatures because many species already may be living near their upper thermal limits. We tested the hypothesis that elevated water temperatures (20, 25, 30, and 35°C) adversely affected the survival and physiology of 2-mo-old juvenile mussels (Lampsilis abrupta, Lampsilis siliquoidea, and Megalonaias nervosa) in 28-d laboratory experiments. The 28-d LT50s (lethal temperature affecting 50% of the population) ranged from 25.3 to 30.3°C across species, and were lowest for L. abrupta and L. siliquoidea. Heart rate of L. siliquoidea was not affected by temperature, but heart rate declined at higher temperatures in L. abrupta and M. nervosa. However, for both of these species, heart rate also declined steadily during the experiment and a strong temperature × time interaction was detected. Juvenile growth was low for all species in all treatments and did not respond directly to temperature, but growth of some species responded to a temperature × time interaction. Responses to thermal stress differed among species, but potential laboratory artifacts may limit applicability of these results to real-world situations. Environmentally relevant estimates of upper thermal tolerances in native mussels are urgently needed to assess the extent of assemblage changes that can be expected in response to global climate change.

Nicorandil, a new vasodilator drug, in patients with essential hypertension.

PubMed

Leonetti, G; Fruscio, M; Gradnik, R; Chianca, R; Bolla, G B; Prandi, P; Zanchetti, A

1989-12-01

In 12 mild to moderate hypertensive patients we investigated the acute antihypertensive efficacy of three different doses of nicorandil, a new vasodilating agent which probably acts by increasing the potassium efflux from smooth muscle cells and causing a cellular hyperpolarization. After a 3-day placebo period the patients were given, according to a double-blind Latin-square randomized design, 10, 20 and 30 mg nicorandil as a single acute dose every other day. Blood pressure and the heart rate were measured in both supine and upright positions at various times for 24 h after the dosing; fractional urine collections were obtained at the end of the placebo period and after each active dose. All doses of nicorandil similarly and significantly (P less than 0.01) reduced supine blood pressure, with a peak after 4-6 h (10 mg: -21/-8 mmHg; 20 mg: -20/-9 mmHg; 30 mg: -29/-17 mmHg), and the effect was still present, though reduced, after 24 h; no change in the heart rate was observed. The results from the upright position were similar. There were no significant changes in urine volume and electrolyte excretion during the nicorandil administration. The three different doses of nicorandil caused similar acute blood pressure reductions without change in the heart rate, nor in the urine volume and urinary sodium.

Music and the heart.

PubMed

Koelsch, Stefan; Jäncke, Lutz

2015-11-21

Music can powerfully evoke and modulate emotions and moods, along with changes in heart activity, blood pressure (BP), and breathing. Although there is great heterogeneity in methods and quality among previous studies on effects of music on the heart, the following findings emerge from the literature: Heart rate (HR) and respiratory rate (RR) are higher in response to exciting music compared with tranquilizing music. During musical frissons (involving shivers and piloerection), both HR and RR increase. Moreover, HR and RR tend to increase in response to music compared with silence, and HR appears to decrease in response to unpleasant music compared with pleasant music. We found no studies that would provide evidence for entrainment of HR to musical beats. Corresponding to the increase in HR, listening to exciting music (compared with tranquilizing music) is associated with a reduction of heart rate variability (HRV), including reductions of both low-frequency and high-frequency power of the HRV. Recent findings also suggest effects of music-evoked emotions on regional activity of the heart, as reflected in electrocardiogram amplitude patterns. In patients with heart disease (similar to other patient groups), music can reduce pain and anxiety, associated with lower HR and lower BP. In general, effects of music on the heart are small, and there is great inhomogeneity among studies with regard to methods, findings, and quality. Therefore, there is urgent need for systematic high-quality research on the effects of music on the heart, and on the beneficial effects of music in clinical settings. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

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. © 2015 S. Karger AG, Basel.

Trends in infective endocarditis hospitalisations at United States children's hospitals from 2003 to 2014: impact of the 2007 American Heart Association antibiotic prophylaxis guidelines.

PubMed

Bates, Katherine E; Hall, Matthew; Shah, Samir S; Hill, Kevin D; Pasquali, Sara K

2017-05-01

National organisations in several countries have recently released more restrictive guidelines for infective endocarditis prophylaxis, including the American Heart Association 2007 guidelines. Initial studies demonstrated no change in infective endocarditis rates over time; however, a recent United Kingdom study suggested an increase; current paediatric trends are unknown. Children (5 years of age. Interrupted time series analysis was used to evaluate rates over time indexed to total hospitalisations. A total of 841 cases were identified. The median age was 13 years (interquartile range 9-15 years). In the pre-guideline period, there was a slight increase in the rate of infective endocarditis by 0.13 cases/10,000 hospitalisations per semi-annual period. In the post-guideline period, the rate of infective endocarditis increased by 0.12 cases/10,000 hospitalisations per semi-annual period. There was no significant difference in the rate of change in the pre- versus post-guidelines period (p=0.895). Secondary analyses in children >5 years of age with CHD and in children hospitalised with any type of infective endocarditis at any age revealed similar results. We found no significant change in infective endocarditis hospitalisation rates associated with revised prophylaxis guidelines over 11 years across 29 United States children's hospitals.

NADPH oxidase contributes to coronary endothelial dysfunction in the failing heart.

PubMed

Zhang, Ping; Hou, Mingxiao; Li, Yunfang; Xu, Xin; Barsoum, Michel; Chen, Yingjie; Bache, Robert J

2009-03-01

Increased reactive oxygen species (ROS) produced by the failing heart can react with nitric oxide (NO), thereby decreasing NO bioavailability. This study tested the hypothesis that increased ROS generation contributes to coronary endothelial dysfunction in the failing heart. Congestive heart failure (CHF) was produced in six dogs by ventricular pacing at 240 beats/min for 4 wk. Studies were performed at rest and during treadmill exercise under control conditions and after treatment with the NADPH oxidase inhibitor and antioxidant apocynin (4 mg/kg iv). Apocynin caused no significant changes in heart rate, aortic pressure, left ventricular (LV) systolic pressure, LV end-diastolic pressure, or maximum rate of LV pressure increase at rest or during exercise in normal or CHF dogs. Apocynin caused no change in coronary blood flow (CBF) in normal dogs but increased CBF at rest and during exercise in animals with CHF (P < 0.05). Intracoronary ACh caused dose-dependent increases of CBF that were blunted in CHF. Apocynin had no effect on the response to ACh in normal dogs but augmented the response to ACh in CHF dogs (P < 0.05). The oxidative stress markers nitrotyrosine and 4-hydroxy-2-nonenal were significantly greater in failing than in normal myocardium. Furthermore, coelenterazine chemiluminescence for O(2)(-) was more than twice normal in failing myocardium, and this difference was abolished by apocynin. Western blot analysis of myocardial lysates demonstrated that the p47(phox) and p22(phox) subunits of NADPH were significantly increased in the failing hearts, while real-time PCR demonstrated that Nox2 mRNA was significantly increased. The data indicate that increased ROS generation in the failing heart is associated with coronary endothelial dysfunction and suggest that NADPH oxidase may contribute to this abnormality.

Modulation of Emotional Appraisal by False Physiological Feedback during fMRI

PubMed Central

Gray, Marcus A.; Harrison, Neil A.; Wiens, Stefan; Critchley, Hugo D.

2007-01-01

Background James and Lange proposed that emotions are the perception of physiological reactions. Two-level theories of emotion extend this model to suggest that cognitive interpretations of physiological changes shape self-reported emotions. Correspondingly false physiological feedback of evoked or tonic bodily responses can alter emotional attributions. Moreover, anxiety states are proposed to arise from detection of mismatch between actual and anticipated states of physiological arousal. However, the neural underpinnings of these phenomena previously have not been examined. Methodology/Principal Findings We undertook a functional brain imaging (fMRI) experiment to investigate how both primary and second-order levels of physiological (viscerosensory) representation impact on the processing of external emotional cues. 12 participants were scanned while judging face stimuli during both exercise and non-exercise conditions in the context of true and false auditory feedback of tonic heart rate. We observed that the perceived emotional intensity/salience of neutral faces was enhanced by false feedback of increased heart rate. Regional changes in neural activity corresponding to this behavioural interaction were observed within included right anterior insula, bilateral mid insula, and amygdala. In addition, right anterior insula activity was enhanced during by asynchronous relative to synchronous cardiac feedback even with no change in perceived or actual heart rate suggesting this region serves as a comparator to detect physiological mismatches. Finally, BOLD activity within right anterior insula and amygdala predicted the corresponding changes in perceived intensity ratings at both a group and an individual level. Conclusions/Significance Our findings identify the neural substrates supporting behavioural effects of false physiological feedback, and highlight mechanisms that underlie subjective anxiety states, including the importance of the right anterior insula in guiding second-order “cognitive” representations of bodily arousal state. PMID:17579718

Frequency-dependence of the slow force response.

PubMed

von Lewinski, Dirk; Zhu, Danan; Khafaga, Mounir; Kockskamper, Jens; Maier, Lars S; Hasenfuss, Gerd; Pieske, Burkert

2008-05-01

Stretch induces biphasic inotropic effects in mammalian myocardium. A delayed component (slow force response, SFR) has been demonstrated in various species, however, experimental conditions varied and the underlying mechanisms are controversial. The physiological relevance of the SFR is poorly understood. Experiments were performed in ventricular muscle strips from failing human hearts and non-failing rabbit hearts. Upon stretch, twitch force was assessed at basal conditions (1 Hz, 37 degrees C) and after changing stimulation frequency with and without blockade of the Na+/H+-exchanger-1 (NHE1) or reverse-mode Na+/Ca2+-exchange (NCX). Action potential duration (APD) was assessed using floating electrodes. Low stimulation rates (0.2 Hz) potentiated and higher stimulation rates (2 and 3 Hz) reduced the SFR. The extent of SFR inhibition by NHE1 or NCX inhibition was not affected by stimulation rate. APD decreased at 0.2 Hz but was not altered at higher stimulation rates. The data demonstrate frequency-dependence of the SFR with greater positive inotropic effects at lower stimulation rates. Subcellular mechanisms underlying the SFR are not fundamentally affected by stimulation rate. The SFR may have more pronounced physiological effects at lower heart rates.

Resting Heart Rate and Outcomes in Patients with Cardiovascular Disease: Where Do We Currently Stand?

PubMed Central

Menown, Ian BA; Davies, Simon; Gupta, Sandeep; Kalra, Paul R; Lang, Chim C; Morley, Chris; Padmanabhan, Sandosh

2013-01-01

Background Data from large epidemiological studies suggest that elevated heart rate is independently associated with cardiovascular and all-cause mortality in patients with hypertension and in those with established cardiovascular disease. Clinical trial findings also suggest that the favorable effects of beta-blockers and other heart rate–lowering agents in patients with acute myocardial infarction and congestive heart failure may be, at least in part, due to their heart rate–lowering effects. Contemporary clinical outcome prediction models such as the Global Registry of Acute Coronary Events (GRACE) score include admission heart rate as an independent risk factor. Aims This article critically reviews the key epidemiology concerning heart rate and cardiovascular risk, potential mechanisms through which an elevated resting heart rate may be disadvantageous and evaluates clinical trial outcomes associated with pharmacological reduction in resting heart rate. Conclusions Prospective randomised data from patients with significant coronary heart disease or heart failure suggest that intervention to reduce heart rate in those with a resting heart rate >70 bpm may reduce cardiovascular risk. Given the established observational data and randomised trial evidence, it now appears appropriate to include reduction of elevated resting heart rate by lifestyle +/− pharmacological therapy as part of a secondary prevention strategy in patients with cardiovascular disease. PMID:22954325

Lower body negative pressure: Third manned Skylab mission

NASA Technical Reports Server (NTRS)

Johnson, R. L.; Hoffler, G. W.; Nicogossian, A. E.; Bergman, S. A., Jr.; Jackson, M. M.

1974-01-01

The crew of the Skylab 4 Mission exhibited physiological changes during their 84-day mission that resembled but in several important areas did not reach the magnitude of changes exhibited in crewmen of the two earlier Skylab flights. At rest all three crewmen showed, in comparison to preflight levels, elevated mean systolic and pulse pressures and decreased mean diastolic and mean arterial pressures. Similar changes were seen in most Skylab 2 and Skylab 3 crewmen. While mean resting heart rates of both the Skylab 3 and Skylab 4 crews were elevated, those of the Skylab 2 crew were, however, lower than during preflight tests. Stressed heart rates followed previous patterns in being consistently elevated over preflight values. Postflight changes in cardiovascular parameters for the most part resembled those seen in previous crewmen of space missions. Their recovery to preflight limits occurred rapidly. In-flight data and subjective impressions of the crewmen confirmed that lower body negative pressure in weightlessness imposed a greater stress upon the cardiovascular system than in earth's gravity.

Heart Rate Fragmentation: A Symbolic Dynamical Approach.

PubMed

Costa, Madalena D; Davis, Roger B; Goldberger, Ary L

2017-01-01

Background: We recently introduced the concept of heart rate fragmentation along with a set of metrics for its quantification. The term was coined to refer to an increase in the percentage of changes in heart rate acceleration sign, a dynamical marker of a type of anomalous variability. The effort was motivated by the observation that fragmentation, which is consistent with the breakdown of the neuroautonomic-electrophysiologic control system of the sino-atrial node, could confound traditional short-term analysis of heart rate variability. Objective: The objectives of this study were to: (1) introduce a symbolic dynamical approach to the problem of quantifying heart rate fragmentation; (2) evaluate how the distribution of the different dynamical patterns ("words") varied with the participants' age in a group of healthy subjects and patients with coronary artery disease (CAD); and (3) quantify the differences in the fragmentation patterns between the two sample populations. Methods: The symbolic dynamical method employed here was based on a ternary map of the increment NN interval time series and on the analysis of the relative frequency of symbolic sequences (words) with a pre-defined set of features. We analyzed annotated, open-access Holter databases of healthy subjects and patients with CAD, provided by the University of Rochester Telemetric and Holter ECG Warehouse (THEW). Results: The degree of fragmentation was significantly higher in older individuals than in their younger counterparts. However, the fragmentation patterns were different in the two sample populations. In healthy subjects, older age was significantly associated with a higher percentage of transitions from acceleration/deceleration to zero acceleration and vice versa (termed "soft" inflection points). In patients with CAD, older age was also significantly associated with higher percentages of frank reversals in heart rate acceleration (transitions from acceleration to deceleration and vice versa , termed "hard" inflection points). Compared to healthy subjects, patients with CAD had significantly higher percentages of soft and hard inflection points, an increased percentage of words with a high degree of fragmentation and a decreased percentage of words with a lower degree of fragmentation. Conclusion: The symbolic dynamical method employed here was useful to probe the newly recognized property of heart rate fragmentation. The findings from these cross-sectional studies confirm that CAD and older age are associated with higher levels of heart rate fragmentation. Furthermore, fragmentation with healthy aging appears to be phenotypically different from fragmentation in the context of CAD.

Heart rate is a marker of amiodarone mortality reduction in severe heart failure. The GESICA-GEMA Investigators. Grupo de Estudio de la Sobrevida en la Insuficiencia Cardiaca en Argentina-Grupo de Estudios Multicéntricos en Argentina.

PubMed

Nul, D R; Doval, H C; Grancelli, H O; Varini, S D; Soifer, S; Perrone, S V; Prieto, N; Scapin, O

1997-05-01

The impact of amiodarone on mortality in patients with severe congestive heart failure (CHF) (New York Heart Association functional classes II [advanced], III and IV; left ventricular ejection fraction < 35%) In the Grupo de Estudio de la Sobrevida en la Insuficiencia Cardiaca en Argentina (GESICA) trial was analyzed in relation to initial mean baseline heart rate (BHR) and its change after 6 months of follow-up. Trials of amiodarone therapy in CHF have produced discordant results, suggesting that the effect is not uniform in all patient subgroups with regard to survival. The present analysis was carried out in 516 patients randomized to receive amiodarone, 300 mg/day (n = 260), or nonantiarrhythmic therapy (n = 256, control group) and followed up for 2 years. Survival was evaluated for patients with a BHR > or = 90 beats/min (control: n = 132; amiodarone: n = 122) and < 90 beats/min (control: n = 124; amiodarone: n = 138). Survival was also analyzed according to heart rate reduction at 6 months for 367 patients. For patients with a BHR > or = 90 beats/min, amiodarone therapy reduced mortality to 38.4% compared with 62.4% in control patients (relative risk [RR] 0.55, 95% confidence interval [CI] 0.35 to 0.95, p < 0.002). Both sudden death (RR 0.46, 95% CI 0.24 to 0.90, p < 0.02) and progressive heart failure death (RR 0.60, 95% CI 0.30 to 1.03, p < 0.06) were reduced, and functional capacity was improved. In patients with a BHR < 90 beats/min, amiodarone did not alter survival. Among 367 patients who completed 6 months of follow-up, amiodarone reduced 2-year mortality only in those with a BHR > or = 90 beats/min, which was reduced at 6 months. Elevated rest heart rates in severe CHF identify a subgroup of patients who benefit from treatment with amiodarone. Amiodarone-induced heart rate slowing may be an important benefit for patients.

Effects of energy drink consumption on corrected QT interval and heart rate variability in young obese Saudi male university students.

PubMed

Alsunni, Ahmed; Majeed, Farrukh; Yar, Talay; AlRahim, Ahmed; Alhawaj, Ali Fouad; Alzaki, Muneer

2015-01-01

Consumption of energy drinks has adverse effects on the heart that might be potentiated in obese individuals. Since the incidence of obesity and use of energy drinks is high among Saudi youth, we used non-invasive tests to study hemodynamic changes produced by altered autonomic cardiac activ.ity following consumption of energy drinks in obese male students. This cross-sectional study was carried out at Department of Physiology, College of Medicine, University of Dammam, Saudi Arabia, over a one-year period from December 2013 to December 2014. In Saudi male university students we measured continuous ECG recordings and a one-minute deep breathing maneuver to measure the expiratory-to-inspiratory ratio, the mean heart rate range (MHRR), the mean percentage variability. (M%VHR) and the corrected QT interval (QTc) at 0, 30 and 60 minutes after consumption of energy drink. We enrolled 31 students (18 overweight/obese and 13 normal weights. QTc was significantly in.creased at 60 min as compared with the resting state in overweight/obese subjects (P=.006). Heart rate variability was significantly less in obese as compared with normal weight subjects at 60 minutes as indicated by E:I ratio, (P=.037), MHRR (P=.012), M%VHR (P=.040) after energy drink consumption. Significant increases in diastolic (P=.020) and mean arterial blood pressure (P=.024) were observed at 30 minutes in the obese group. Hemodynamic changes after intake of energy drinks in obese subjects indicate that obesity and energy drinks could synergistically induce harmful effects. This finding warrants efforts to caution the obese on intake of energy drinks and timely intervention to motivate changes in lifestyle.

Behavioural and physiological measures indicate subtle variations in the emotional valence of young pigs.

PubMed

Leliveld, Lisette M C; Düpjan, Sandra; Tuchscherer, Armin; Puppe, Birger

2016-04-01

In the study of animal emotions, emotional valence has been found to be difficult to measure. Many studies of farm animals' emotions have therefore focussed on the identification of indicators of strong, mainly negative, emotions. However, subtle variations in emotional valence, such as those caused by rather moderate differences in husbandry conditions, may also affect animals' mood and welfare when such variations occur consistently. In this study, we investigated whether repeated moderate aversive or rewarding events could lead to measurable differences in emotional valence in young, weaned pigs. We conditioned 105 female pigs in a test arena to either a repeated startling procedure (sudden noises or appearances of objects) or a repeated rewarding procedure (applesauce, toy and straw) over 11 sessions. Control pigs were also regularly exposed to the same test arena but without conditioning. Before and after conditioning, we measured heart rate and its variability as well as the behavioural reactions of the subjects in the test arena, with a special focus on detailed acoustic analyses of their vocalisations. The behavioural and heart rate measures were analysed as changes compared to the baseline values before conditioning. A limited number of the putative indicators of emotional valence were affected by the conditioning. We found that the negatively conditioned pigs showed changes that were significantly different from those in control pigs, namely a decrease in locomotion and an increase in standing. The positively conditioned pigs, however, showed a stronger increase in heart rate and a smaller decrease in SDNN (a heart rate variability parameter indicating changes in autonomic regulation) compared to the controls. Compared to the negatively conditioned pigs, the positively conditioned pigs produced fewer vocalisations overall as well as fewer low-frequency grunts but more high-frequency grunts. The low-frequency grunts of the negatively conditioned pigs also showed lower frequency parameters (bandwidth, maximum frequency, 25% and 50% quartiles) compared to those of the positively conditioned pigs. In any of the statistically significant results, the conditioning accounted for 1.5-11.9% of variability in the outcome variable. Hence, we conclude that repeated moderate aversive and rewarding events have weak but measurable effects on some aspects of behaviour and physiology in young pigs, possibly indicating changes in emotional valence, which could ultimately affect their welfare. The combination of ethophysiological indicators, i.e., the concurrent examination of heart rate measures, behavioural responses and especially vocalisation patterns, as used in the current study, might be a useful way of examining subtle effects on emotional valence in further studies. Copyright © 2016 Elsevier Inc. All rights reserved.

Weather-induced ischemia and arrhythmia in patients undergoing cardiac rehabilitation: another difference between men and women

NASA Astrophysics Data System (ADS)

Schneider, Alexandra; Schuh, Angela; Maetzel, Friedrich-Karl; Rückerl, Regina; Breitner, Susanne; Peters, Annette

2008-07-01

Given the accumulating evidence that people with underlying heart disease are a particularly vulnerable group for triggers like changing meteorological parameters, the objective of this longitudinal study was to analyze the influence of weather parameters on blood pressure, arrhythmia and ischemia in cardiovascular patients. A panel study with repeated measurements was conducted in a rehabilitation clinic in Timmendorfer Strand (Baltic Sea, Germany) with 872 cardiovascular patients. Heart rate, blood pressure and electrocardiography changes were measured during repeated bicycle ergometries. Generalized Estimating Equations were used for regression analyses of immediate, delayed and cumulative influences of the daily measured meteorological data. For men, a decrease in air temperature and in water vapor pressure doubled the risk of ST-segment depression during ergometry [odds ratio (OR) for 1 day delay: 1.88 (1.24; 2.83) for air temperature] with a delay of 1-2 days. For women, an increase of their heart rate before the start of the ergometry [same day: 4.36 beats/min (0.99; 7.74) for air temperature] and a 2- to 3-fold higher risk for ventricular ectopic beats [1 day delay: OR 2.43 (1.17; 5.05) for air temperature] was observed with an increase in temperature and water vapor pressure in almost all analyzed time-windows. The study indicates that meteorological parameters can induce changes in heart function which may lead to adverse cardiovascular events especially in susceptible, diseased individuals. The observed effect on ST-segment depression could be a link between the association of weather changes and cardiovascular morbidity and mortality.

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.

Reversible heart rhythm complexity impairment in patients with primary aldosteronism

NASA Astrophysics Data System (ADS)

Lin, Yen-Hung; Wu, Vin-Cent; Lo, Men-Tzung; Wu, Xue-Ming; Hung, Chi-Sheng; Wu, Kwan-Dun; Lin, Chen; Ho, Yi-Lwun; Stowasser, Michael; Peng, Chung-Kang

2015-08-01

Excess aldosterone secretion in patients with primary aldosteronism (PA) impairs their cardiovascular system. Heart rhythm complexity analysis, derived from heart rate variability (HRV), is a powerful tool to quantify the complex regulatory dynamics of human physiology. We prospectively analyzed 20 patients with aldosterone producing adenoma (APA) that underwent adrenalectomy and 25 patients with essential hypertension (EH). The heart rate data were analyzed by conventional HRV and heart rhythm complexity analysis including detrended fluctuation analysis (DFA) and multiscale entropy (MSE). We found APA patients had significantly decreased DFAα2 on DFA analysis and decreased area 1-5, area 6-15, and area 6-20 on MSE analysis (all p < 0.05). Area 1-5, area 6-15, area 6-20 in the MSE study correlated significantly with log-transformed renin activity and log-transformed aldosterone-renin ratio (all p < = 0.01). The conventional HRV parameters were comparable between PA and EH patients. After adrenalectomy, all the altered DFA and MSE parameters improved significantly (all p < 0.05). The conventional HRV parameters did not change. Our result suggested that heart rhythm complexity is impaired in APA patients and this is at least partially reversed by adrenalectomy.

Absence of nocturnal fall in blood pressure in elderly persons with Alzheimer-type dementia.

PubMed

Otsuka, A; Mikami, H; Katahira, K; Nakamoto, Y; Minamitani, K; Imaoka, M; Nishide, M; Ogihara, T

1990-09-01

Circadian changes of the blood pressure and heart rate in elderly normotensive bedridden patients with severe dementia of the Alzheimer type (group D) were compared with those in elderly normotensive bedridden patients without dementia (group R), normotensive subjects with normal daily activity (group N), and hypertensive patients with normal daily activity (group H). In groups R, N, and H, the blood pressure increased in the afternoon and decreased at midnight; in group D, however, although it increased in the afternoon, it did not decrease at night. The circadian changes of the heart rate were similar in all four groups, showing maxima in the afternoon and minima at midnight. Thus, a specific alteration was found in the circadian rhythm of the blood pressure in patients with Alzheimer-type dementia.

Heart Rate Dynamics During A Treadmill Cardiopulmonary Exercise Test in Optimized Beta-Blocked Heart Failure Patients

PubMed Central

Carvalho, Vitor Oliveira; Guimarães, Guilherme Veiga; Ciolac, Emmanuel Gomes; Bocchi, Edimar Alcides

2008-01-01

BACKGROUND Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4±11.1%) compared to controls (98.6±2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2±0.5 for controls and 1.15±1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age, while no patients in the heart failure group reached the maximum. Moreover, the % increase of heart rate from rest to peak exercise between heart failure (48±9%) and control (53±8%) was not different (p=0.157). CONCLUSION No patient in the heart failure group reached the maximum heart rate for their age during a treadmill cardiopulmonary exercise test, despite the fact that the percentage increase of heart rate was similar to sedentary normal subjects. A heart rate increase in optimized beta-blocked heart failure patients during cardiopulmonary exercise test over 65% of the maximum age-adjusted value should be considered an effort near the maximum. This information may be useful in rehabilitation programs and ischemic tests, although further studies are required. PMID:18719758

When an Increase in Central Systolic Pressure Overrides the Benefits of Heart Rate Lowering.

PubMed

Messerli, Franz H; Rimoldi, Stefano F; Bangalore, Sripal; Bavishi, Chirag; Laurent, Stephane

2016-08-16

An elevated resting heart rate has been unequivocally linked to adverse cardiovascular events. Conversely, a physiologically low heart rate may confer longevity benefits. Moreover, pharmacological heart rate lowering reduces cardiovascular outcomes in patients with heart failure, with the magnitude of the reduction associated with survival benefit. In contrast, pharmacological heart rate lowering paradoxically increases cardiovascular events in hypertension, possibly because it elicits a ventricular-vascular mismatch, leading to increased central systolic blood pressure (BP). By the same hemodynamic mechanism, pharmacological heart rate lowering also engenders an increase in central (aortic) BP in coronary heart disease and, as a consequence, fails to decrease myocardial oxygen consumption. Whether in heart failure, hypertension, or coronary heart disease, or even athletes, heart rate lowering consistently increases central systolic pressure. The increase in central systolic BP is prone to abolish the potential benefits of heart rate lowering interventions, possibly accounting for failure to reduce outcomes in patients with hypertension and coronary artery disease. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Heart rate monitoring mobile applications

PubMed Central

2016-01-01

Total number of times a heart beats in a minute is known as the heart rate. Traditionally, heart rate was measured using clunky gadgets but these days it can be measured with a smartphone’s camera. This can help you measure your heart rate anywhere and at anytime, especially during workouts so you can adjust your workout intensity to achieve maximum health benefits. With simple and easy to use mobile app, ‘Unique Heart Rate Monitor’, you can also maintain your heart rate history for personal reflection and sharing with a provider. PMID:28293594

Quantifying the Interactions between Maternal and Fetal Heart Rates by Transfer Entropy.

PubMed

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

2015-01-01

Evidence of the short term relationship between maternal and fetal heart rates has been found in previous studies. However there is still limited knowledge about underlying mechanisms and patterns of the coupling throughout gestation. In this study, Transfer Entropy (TE) was used to quantify directed interactions between maternal and fetal heart rates at various time delays and gestational ages. Experimental results using maternal and fetal electrocardiograms showed significant coupling for 63 out of 65 fetuses, by statistically validating against surrogate pairs. Analysis of TE showed a decrease in transfer of information from fetus to the mother with gestational age, alongside the maturation of the fetus. On the other hand, maternal to fetal TE was significantly greater in mid (26-31 weeks) and late (32-41 weeks) gestation compared to early (16-25 weeks) gestation (Mann Whitney Wilcoxon (MWW) p<0.05). TE further increased from mid to late, for the fetuses with RMSSD of fetal heart rate being larger than 4 msec in the late gestation. This difference was not observed for the fetuses with smaller RMSSD, which could be associated with the quiet sleep state. Delay in the information transfer from mother to fetus significantly decreased (p = 0.03) from mid to late gestation, implying a decrease in fetal response time. These changes occur concomitant with the maturation of the fetal sensory and autonomic nervous systems with advancing gestational age. The effect of maternal respiratory rate derived from maternal ECG was also investigated and no significant relationship was found between breathing rate and TE at any lag. In conclusion, the application of TE with delays revealed detailed information on the fetal-maternal heart rate coupling strength and latency throughout gestation, which could provide novel clinical markers of fetal development and well-being.

Quantifying the Interactions between Maternal and Fetal Heart Rates by Transfer Entropy

PubMed Central

Marzbanrad, Faezeh; Kimura, Yoshitaka; Palaniswami, Marimuthu; Khandoker, Ahsan H.

2015-01-01

Evidence of the short term relationship between maternal and fetal heart rates has been found in previous studies. However there is still limited knowledge about underlying mechanisms and patterns of the coupling throughout gestation. In this study, Transfer Entropy (TE) was used to quantify directed interactions between maternal and fetal heart rates at various time delays and gestational ages. Experimental results using maternal and fetal electrocardiograms showed significant coupling for 63 out of 65 fetuses, by statistically validating against surrogate pairs. Analysis of TE showed a decrease in transfer of information from fetus to the mother with gestational age, alongside the maturation of the fetus. On the other hand, maternal to fetal TE was significantly greater in mid (26–31 weeks) and late (32–41 weeks) gestation compared to early (16–25 weeks) gestation (Mann Whitney Wilcoxon (MWW) p<0.05). TE further increased from mid to late, for the fetuses with RMSSD of fetal heart rate being larger than 4 msec in the late gestation. This difference was not observed for the fetuses with smaller RMSSD, which could be associated with the quiet sleep state. Delay in the information transfer from mother to fetus significantly decreased (p = 0.03) from mid to late gestation, implying a decrease in fetal response time. These changes occur concomitant with the maturation of the fetal sensory and autonomic nervous systems with advancing gestational age. The effect of maternal respiratory rate derived from maternal ECG was also investigated and no significant relationship was found between breathing rate and TE at any lag. In conclusion, the application of TE with delays revealed detailed information on the fetal-maternal heart rate coupling strength and latency throughout gestation, which could provide novel clinical markers of fetal development and well-being. PMID:26701122