The effect of sinus node depression on heart rate variability in humans using zatebradine, a selective bradycardic agent

1998 ◽  
Vol 76 (7-8) ◽  
pp. 806-810 ◽  
Author(s):  
Yaariv Khaykin ◽  
Paul Dorian ◽  
Anthony Tang ◽  
M Green ◽  
Jan Mitchell ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Sinus Node ◽  
Isotonic Saline ◽  
Low Frequency ◽  
Structural Heart Disease ◽  
Total Power ◽  
Control Group ◽  
Bradycardic Agent ◽  
Normal Sinus

Zatebradine is a bradycardic agent with a selective effect on the pacemaker current in the sinus node. The effect of such drugs on heart rate variability is not known. Thirty-six patients without structural heart disease were randomly assigned to receive 10 mg of zatebradine i.v. (n = 24) or isotonic saline (n = 12). Heart rate variability (HRV) was recorded as power in the very low frequency (VLF, 0.003-0.040 Hz), low frequency (LF, 0.040-0.150 Hz), and high frequency (HF, 0.150-0.400 Hz) spectral bands as well as total power (TP, 0.003-0.400 Hz) during 5-min ECG acquisitions at baseline, 30, and 60 min following the start of the infusion. No change in heart rate variability was detected in the control group. Zatebradine significantly reduced heart rate variability at 60 min in all frequency bands: VLF (-12 ± 4%, p < 0.001), LF (-19 ± 4%, p < 0.001), and HF (-26 ± 5%, p < 0.001). The reduction in HRV following zatebradine is due to depression of sinus node response to all external stimuli and underscores the need for documentation of normal sinus node function in HRV research.Key words: zatebradine, sinus node, heart rate variability, HRV, autonomic nervous system.

scholarly journals The Effects of Guided Imagery on Heart Rate Variability in Simulated Spaceflight Emergency Tasks Performers

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Zhang Yijing ◽  
Du Xiaoping ◽  
Liu Fang ◽  
Jing Xiaolu ◽  
Wu Bin
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Guided Imagery ◽  
Training Session ◽  
Low Frequency ◽  
Total Power ◽  
Control Group ◽  
Imagery Training ◽  
Imagery Group ◽  
Student Subjects

Objectives. The present study aimed to investigate the effects of guided imagery training on heart rate variability in individuals while performing spaceflight emergency tasks.Materials and Methods. Twenty-one student subjects were recruited for the experiment and randomly divided into two groups: imagery group (n=11) and control group (n=10). The imagery group received instructor-guided imagery (session 1) and self-guided imagery training (session 2) consecutively, while the control group only received conventional training. Electrocardiograms of the subjects were recorded during their performance of nine spaceflight emergency tasks after imagery training.Results. In both of the sessions, the root mean square of successive differences (RMSSD), the standard deviation of all normal NN (SDNN), the proportion of NN50 divided by the total number of NNs (PNN50), the very low frequency (VLF), the low frequency (LF), the high frequency (HF), and the total power (TP) in the imagery group were significantly higher than those in the control group. Moreover, LF/HF of the subjects after instructor-guided imagery training was lower than that after self-guided imagery training.Conclusions. Guided imagery was an effective regulator for HRV indices and could be a potential stress countermeasure in performing spaceflight tasks.

scholarly journals The Influence ofNrf2on Cardiac Responses to Environmental Stressors

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Reuben Howden ◽  
Eva Gougian ◽  
Marcus Lawrence ◽  
Samantha Cividanes ◽  
Wesley Gladwell ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Low Frequency ◽  
Therapeutic Strategies ◽  
Environmental Stressors ◽  
Total Power ◽  
Airborne Pollutants ◽  
Cardiac Responses

Nrf2protects the lung from adverse responses to oxidants, including 100% oxygen (hyperoxia) and airborne pollutants like particulate matter (PM) exposure, but the role ofNrf2on heart rate (HR) and heart rate variability (HRV) responses is not known. We hypothesized that genetic disruption ofNrf2would exacerbate murine HR and HRV responses to severe hyperoxia or moderate PM exposures.Nrf2-/-andNrf2+/+mice were instrumented for continuous ECG recording to calculate HR and HRV (low frequency (LF), high frequency (HF), and total power (TP)). Mice were then either exposed to hyperoxia for up to 72 hrs or aspirated with ultrafine PM (UF-PM). Compared to respective controls, UF-PM induced significantly greater effects on HR (P<0.001) and HF HRV (P<0.001) inNrf2-/-mice compared toNrf2+/+mice.Nrf2-/-mice tolerated hyperoxia significantly less thanNrf2+/+mice (~22 hrs;P<0.001). Reductions in HR, LF, HF, and TP HRV were also significantly greater inNrf2-/-compared toNrf2+/+mice (P<0.01). Results demonstrate thatNrf2deletion increases susceptibility to change in HR and HRV responses to environmental stressors and suggest potential therapeutic strategies to prevent cardiovascular alterations.

scholarly journals Effect of Acupuncture on Heart Rate Variability: A Systematic Review

2014 ◽  
Vol 2014 ◽  
pp. 1-19 ◽  
Author(s):  
Joanne W. Y. Chung ◽  
Vincent C. M. Yan ◽  
Hongwei Zhang
Keyword(s):  
Systematic Review ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Healthy Subjects ◽  
Keyword Search ◽  
Data Extraction ◽  
Meta Analysis ◽  
Low Frequency ◽  
Control Group

Aim.To summarize all relevant trials and critically evaluate the effect of acupuncture on heart rate variability (HRV).Method.This was a systematic review with meta-analysis. Keyword search was conducted in 7 databases for randomized controlled trials (RCTs). Data extraction and risk of bias were done.Results.Fourteen included studies showed a decreasing effect of acupuncture on low frequency (LF) and low frequency to high frequency ratio (LF/HF ratio) of HRV for nonhealthy subjects and on normalized low frequency (LF norm) for healthy subjects. The overall effect was in favour of the sham/control group for high frequency (HF) in nonhealthy subjects and for normalized high frequency (HF norm) in healthy subjects. Significant decreasing effect on HF and LF/HF ratio of HRV when acupuncture was performed on ST36 among healthy subjects and PC6 among both healthy and nonhealthy subjects, respectively.Discussion.This study partially supports the possible effect of acupuncture in modulating the LF of HRV in both healthy and nonhealthy subjects, while previous review reported that acupuncture did not have any convincing effect on HRV in healthy subjects. More published work is needed in this area to determine if HRV can be an indicator of the therapeutic effect of acupuncture.

Abstract P315: Increase in Stress May Contribute to Lower Heart Rate Variability in Healthy Young Subjects

Circulation ◽  
2012 ◽  
Vol 125 (suppl_10) ◽  
Author(s):  
Amanda C Costa ◽  
Ana Gabriela C Silva ◽  
Cibele T Ribeiro ◽  
Guilherme A Fregonezi ◽  
Fernando A Dias
Keyword(s):  
Cardiovascular Disease ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Healthy Volunteers ◽  
Perceived Stress ◽  
Low Frequency ◽  
Statistical Correlation ◽  
Total Power ◽  
The Impact ◽  
Nonparametric Correlation

Background: Stress is one of the risk factors for cardiovascular disease and decreased heart rate variability is associated to increased mortality in some cardiac diseases. The aim of the study was to assess the impact of perceived stress on cardiac autonomic regulation in young healthy volunteers. Methods: 35 young healthy volunteers (19 to 29 years old, 6 men) from a Brazilian population were assessed for perceived stress by the translated and validated Perceived Stress Scale (PSS, 14 questions) and had the R-R intervals recorded at rest on supine position (POLAR RS800CX) and analyzed (5 minutes, Kubius HRV software) by Fast-Fourier Transform for quantification of Heart Rate Variability (HRV). Results: Average data (±SD) for age, heart rate, BMI, waist circumference and percentage of body fat (%BF) were: 21.3±2.7 years; 65.5±7.9 bpm; 22.3±1.9 Kg/m 2 ; 76.0±6.1 cm and 32.1±6.6%; respectively. The mean score for the PSS-14 was 23.5±7.2 and for the HRV parameter as follow: SSDN=54.8±21.2ms; rMSSD=55.9±32.2ms; low-frequency (LF)= 794.8±579.7ms 2 ; High-frequency (HF)= 1508.0±1783.0 ms 2 ; LF(n.u.)= 41.1±16.2; HF(n.u.)= 58.9±16.2; LF/HF=0.89±0.80 and Total power (TP)= 3151±2570ms 2 . Spearman nonparametric correlation was calculated and there was a significant correlation of PSS-14 scores and LF (ms 2 ) (r=−0.343; p= 0.044). Other HRV variables did not shown significant correlation but also had negative values for Spearman r (TP r=−0.265, p=0.124; HF r=−0.158; SSDN r=−0.207; rMSSD r=−0.243, p=0.160). LF/HF and LF(n.u.) did not correlate to PSS-14 having Spearman r very close to zero (LF/HF r=−0.007, p=0.969; LF(n.u.) r=−0.005, p=0.976). No correlation was found for HRV parameters and BMI and there was a trend for statistical correlation of %BF and LF (ms 2 ) (r=−0.309, p=0.071). Conclusions: These data demonstrate a possible association of perceived stress level and HRV at rest. Changes in LF can be a consequence of both sympathetic and parasympathetic activity, however, analyzing the other variables HF, TP, SSDN and rMSSD (all negative Spearman r) and due to the lack of changes in LF/HF ratio and LF(n.u.) we interpret that increased stress may be associated to decrease in overall heart rate variability. These changes were seen in healthy individuals and may point out an important mechanism in cardiovascular disease development.

scholarly journals Heart Rate Variability and Cardiovascular Reflex Tests for Assessment of Autonomic Functions in Preeclampsia

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Meenakshi Chaswal ◽  
Raj Kapoor ◽  
Achla Batra ◽  
Savita Verma ◽  
Bhupendra S. Yadav
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Pregnant Women ◽  
Frequency Domain ◽  
Low Frequency ◽  
Normal Pregnancy ◽  
Total Power ◽  
Autonomic Functions ◽  
Cardiovascular Reflex ◽  
Cardiovascular Reflex Tests

Alterations in the autonomic cardiovascular control have been implicated to play an important etiologic role in preeclampsia. The present study was designed to evaluate autonomic functions in preeclamptic pregnant women and compare the values with normotensive pregnant and healthy nonpregnant controls. Assessment of autonomic functions was done by cardiovascular reflex tests and by analysis of heart rate variability (HRV). Cardiovascular reflex tests included deep breathing test (DBT) and lying to standing test (LST). HRV was analyzed in both time and frequency domain for quantifying the tone of autonomic nervous system to the heart. The time domain measures included standard deviation of normal R-R intervals (SDNN) and square root of mean squared differences of successive R-R intervals (RMSSD). In the frequency domain we measured total power (TP), high frequency (HF) power, low frequency (LF) power, and LF/HF ratio. Cardiovascular reflex tests showed a significant parasympathetic deficit in preeclamptic women. Among parameters of HRV, preeclamptic group had lower values of SDNN, RMSSD, TP, HF, and LF (ms2) and higher value of LF in normalised units along with high LF/HF ratio compared to normotensive pregnant and nonpregnant controls. Furthermore, normotensive pregnant women had lower values of SDNN, TP, and LF component in both absolute power and normalised units compared to nonpregnant females. The results confirm that normal pregnancy is associated with autonomic disturbances which get exaggerated in the state of preeclampsia.

Mind–body interactive qigong improves physical and mental aspects of quality of life in inpatients with stroke: A randomized control study

2019 ◽  
Vol 18 (8) ◽  
pp. 658-666 ◽  
Author(s):  
Ching-Hsiang Chen ◽  
Kuo-Sheng Hung ◽  
Yu-Chu Chung ◽  
Mei-Ling Yeh
Keyword(s):  
Quality Of Life ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Standard Care ◽  
Low Frequency ◽  
Control Group ◽  
Subacute Stroke ◽  
Interactive Exercise

Background: Stroke, a medical condition that causes physical disability and mental health problems, impacts negatively on quality of life. Post-stroke rehabilitation is critical to restoring quality of life in these patients. Objectives: This study was designed to evaluate the effect of a mind–body interactive qigong intervention on the physical and mental aspects of quality of life, considering bio-physiological and mental covariates in subacute stroke inpatients. Methods: A randomized controlled trial with repeated measures design was used. A total of 68 participants were recruited from the medical and rehabilitation wards at a teaching hospital in northern Taiwan and then randomly assigned either to the Chan-Chuang qigong group, which received standard care plus a 10-day mind–body interactive exercise program, or to the control group, which received standard care only. Data were collected using the National Institutes of Health Stroke Scale, Hospital Anxiety and Depression Scale, Short Form-12, stroke-related neurologic deficit, muscular strength, heart rate variability and fatigue at three time points: pre-intervention, halfway through the intervention (day 5) and on the final day of the intervention (day 10). Results: The results of the mixed-effect model analysis showed that the qigong group had a significantly higher quality of life score at day 10 ( p<0.05) than the control group. Among the covariates, neurologic deficit ( p=0.04), muscle strength ( p=0.04), low frequency to high frequency ratio ( p=0.02) and anxiety ( p=0.04) were significantly associated with changes in quality of life. Conversely, heart rate, heart rate variability (standard deviation of normal-to-normal intervals, low frequency and high frequency), fatigue and depression were not significantly associated with change in quality of life ( p >0.05). Conclusions: This study supports the potential benefits of a 10-day mind–body interactive exercise (Chan-Chuang qigong) program for subacute stroke inpatients and provides information that may be useful in planning adjunctive rehabilitative care for stroke inpatients.

scholarly journals Assessment of heart rate variability during different propofol effect site concentrations in patients with supratentorial tumours: A pilot study

2017 ◽  
Vol 04 (02) ◽  
pp. 108-113
Author(s):  
Mohit Mittal ◽  
Radhakrishnan Muthuchellappan ◽  
G. Umamaheswara Rao ◽  
K. Kavyashree ◽  
K. Vishnuprasad
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Total Power ◽  
Control Group ◽  
Baseline Heart Rate ◽  
Study Group ◽  
Intracranial Tumour ◽  
Anaesthetic Induction ◽  
Effect Site ◽  
Supratentorial Tumours

Abstract Background: Impaired autonomic function (AF) can result in adverse cardiovascular events during the perioperative period. Literature suggests that patients with intracranial space-occupying lesions experience impaired AF depending on the site of tumour and associated raised intracranial pressure (ICP). The complex interaction between general anaesthetics, AF and intracranial tumours with raised ICP has not been extensively studied. Objective: This study was aimed at evaluating the cardiac AF (in terms of heart rate variability [HRV]) in patients undergoing surgery for supratentorial tumours, at baseline and at different propofol effect site concentrations (Ce) during anaesthetic induction and the results were compared with patients undergoing non-cranial surgeries. Materials and Methods: In this prospective observational study, consecutive adult patients undergoing surgeries for supratentorial tumour (study group) and brachial plexus injury (control group) were recruited. Electrocardiogram was recorded for 5 min at three time points – before propofol induction, at propofol Ce 2 μg/ml and at Ce 4 μg/ml. Results: Forty-five patients were recruited, 24 in study group and 21 in control group. In spite of similar baseline heart rate and blood pressure, low frequency (LF), high frequency (HF) and total power were significantly higher in control group. Baseline LF/HF, though higher in patients with intracranial tumour (craniotomy: 2.2 ± 2.2, control: 1.2 ± 1.1), was not significantly different between the two groups (P = 0.197). HRV variables in both the groups changed the same way in response to the increasing propofol Ce. Conclusion: HRV measurements were significantly different at baseline between the two groups. Following propofol administration, haemodynamic changes and HRV changes were similar in both the groups and also between the two groups.

Elevated heart rate variability in physically active postmenopausal women: a cardioprotective effect?

1996 ◽  
Vol 271 (2) ◽  
pp. H455-H460 ◽  
Author(s):  
K. P. Davy ◽  
N. L. Miniclier ◽  
J. A. Taylor ◽  
E. T. Stevenson ◽  
D. R. Seals
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Postmenopausal Women ◽  
High Frequency ◽  
Low Frequency ◽  
Total Power ◽  
High Frequency Power ◽  
Fat Percentage ◽  
Physically Active ◽  
Frequency Power

Coronary heart disease (CHD) and cardiac sudden death (CSD) incidence accelerates after menopause, but the incidence is lower in physically active versus less active women. Low heart rate variability (HRV) is a risk factor for CHD and CSD. The purpose of the present investigation was to test the hypothesis that HRV at rest is greater in physically active compared with less active postmenopausal women. If true, we further hypothesized that the greater HRV in the physically active women would be closely associated with an elevated spontaneous cardiac baroreflex sensitivity (SBRS). HRV (both time and frequency domain measures) and SBRS (sequence method) were measured during 5-min periods of controlled frequency breathing (15 breaths/min) in the supine, sitting, and standing postures in 9 physically active postmenopausal women (age = 53 +/- 1 yr) and 11 age-matched controls (age = 56 +/- 2 yr). Body weight, body mass index, and body fat percentage were lower (P < 0.01) and maximal oxygen uptake was higher (P < 0.01) in the physically active group. The standard deviation of the R-R intervals (time domain measure) was higher in all postures in the active women (P < 0.05) as were the high-frequency, low-frequency, and total power of HRV. SBRS also was higher (P < 0.05) in the physically active women in all postures and accounted for approximately 70% of the variance in the high-frequency power of HRV (P < 0.05). The results of the present investigation indicate that physically active postmenopausal women demonstrate higher levels of HRV compared with age-matched, less active women. Furthermore, SBRS accounted for the majority of the variance in the high-frequency power of HRV, suggesting the possibility of a mechanistic link with cardiac vagal modulation of heart rate. Our findings may provide insight into a possible cardioprotective mechanism in physically active postmenopausal women.

The Comparisons of Heart Rate Variability and Perceived Exertion During Simulated Cycling with Various Viewing Devices

2008 ◽  
Vol 17 (6) ◽  
pp. 575-583 ◽  
Author(s):  
Shih-Fong Huang ◽  
Po-Yi Tsai ◽  
Wen-Hsu Sung ◽  
Chih-Yung Lin ◽  
Tien-Yow Chuang
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Perceived Exertion ◽  
Low Frequency ◽  
Control Group ◽  
Threshold Intensity ◽  
Power Spectral ◽  
Significant Difference

Sympathovagal modulation during immersion in a virtual environment is an important influence on human performance of a task. The aim of this study is to investigate sympathovagal modulation using heart rate variability and perceived exertion during exercise in a virtual reality (VR) environment. Sixteen young healthy volunteers were tested while using a stationary bicycle and maintained at an anaerobic threshold intensity for exercise sessions of approximately 10 min duration. Four randomized viewing alternatives were provided including desktop monitor, projector, head mounted device (HMD), and no simulation display. The “no simulation display” served as the control group. A quick ramp exercise test was conducted and maintained at an anaerobic threshold intensity for each session to evaluate power spectral density and rating of perceived exertion (RPE). The sampled heart rate data were rearranged by cubic spline interpolation into power spectrums spanning the ultra-low frequency (ULF) to high frequency (HF) range. A significant difference was found between the no-display and projector groups for total power (TP) and very low frequency (VLF) components. In particular, there was a significant difference when comparing HMD and no-display exercise RPE curves within 6 min of cycling and at the termination of the exercise. A significant difference was also achieved in projector vs. control group comparison at the termination of the exercise. Our results indicate that the use of HMD and the projected VR during cycling can reduce the TP and VLF power spectral density through a proposed decrease in the renin-angiotensin system, with the implication that this humoral effect may enable anaerobic exercise for longer durations through a reduction in sympathetic tone and subsequent increased blood flow to the muscles.

NEUROCARDIAC-CARDIORESPIRATORY INTERACTION OF HEART-BRAIN MAILUNS SYNCHRONY AT DEEP ZEN MEDITATION

2016 ◽  
Vol 28 (06) ◽  
pp. 1650039
Author(s):  
Pei-Chen Lo ◽  
Wu Jue Miao Tian
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Low Frequency ◽  
Transition Process ◽  
Total Power ◽  
Sinus Arrhythmia ◽  
Respiration Rhythm ◽  
Scientific Hypothesis ◽  
Cardiorespiratory Interaction ◽  
Electrical Impulses

Innovatively new behaviors of heart rate variability caused by special heart-transition process were observed in the long-term, well-experienced Zen practitioners while practicing the heart-to-heart imprint sealing (HHIS) Zen meditation. HHIS Zen practice involves specific neurocardiac-cardiorespiratory interaction while on the way of realizing the heart-dominant, detached brain. Results of analyzing the electrocardiogram and respiratory signals of 10 experienced practitioners reveal several distinctive characteristics: (1) remarkably linear correlation between standard deviation of the normal R-to-R intervals, SDNN, and total power in very-low-frequency (VLF, 0.0033–0.04[Formula: see text]Hz) band of power spectrum of the heart-rate sequence, (2) time-varying VLF power dominating over the low-frequency and high-frequency power in heart rate variability (HRV) variations, (3) intermittent transition into slowly, deeply abdominal respiration inducing a boost of heart rates, (4) heart-rate baseline slowly fluctuating at 0.005–0.0067[Formula: see text]Hz, about 1.5–2 cycles in 5-min period, and (5) remarkable respiratory sinus arrhythmia (RSA) synchrony between heart rate and respiration rhythm. This paper proposes a rational scientific hypothesis for the neurocardiac-cardiorespiratory mechanism. The unique scheme of HHIS Zen meditation involves the spiritual-qi concentration and refinement for pinpointing into the particular energy centers, mailuns. Ignition by a subtle, deepest abdominal respiration, electrical impulses rapidly transmit from solar plexus to branchial plexuses to activate unique heart-transition process. Simultaneously, another branch streams upward the spinal cord to cervical plexus and brainstem that effectively harmonizes neurocardiac interactions. To investigate the underlying behaviors, time-domain and frequency-domain HRV based on continuous wavelet transform were employed.

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