1,723 research outputs found
Validity of telemetric-derived measures of heart rate variability: a systematic review
Heart rate variability (HRV) is a widely accepted indirect measure of autonomic function with widespread application across many settings. Although traditionally measured from the 'gold standard' criterion electrocardiography (ECG), the development of wireless telemetric heart rate monitors (HRMs) extends the scope of the HRV measurement. However, the validity of telemetric-derived data against the criterion ECG data is unclear. Thus, the purpose of this study was twofold: (a) to systematically review the validity of telemetric HRM devices to detect inter-beat intervals and aberrant beats; and (b) to determine the accuracy of HRV parameters computed from HRM-derived inter-beat interval time series data against criterion ECG-derived data in healthy adults aged 19 to 62 yrs. A systematic review of research evidence was conducted. Four electronic databases were accessed to obtain relevant articles (PubMed, EMBASE, MEDLINE and SPORTDiscus. Articles published in English between 1996 and 2016 were eligible for inclusion. Outcome measures included temporal and power spectral indices (Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (1996). The review confirmed that modern HRMs (Polar® V800™ and Polar® RS800CX™) accurately detected inter-beat interval time-series data. The HRV parameters computed from the HRM-derived time series data were interchangeable with the ECG-derived data. The accuracy of the automatic in-built manufacturer error detection and the HRV algorithms were not established. Notwithstanding acknowledged limitations (a single reviewer, language bias, and the restricted selection of HRV parameters), we conclude that the modern Polar® HRMs offer a valid useful alternative to the ECG for the acquisition of inter-beat interval time series data, and the HRV parameters computed from Polar® HRM-derived inter-beat interval time series data accurately reflect ECG-derived HRV metrics, when inter-beat interval data are processed and analyzed using identical protocols, validated algorithms and software, particularly under controlled and stable conditions
Investigation of pathophysiologic trends in Caucasian and Afro-American hypertensives by means of heart rate variability recording during upright tilt-table testing
The incidence of hypertension is more prevalent among the Afro-American population than the Caucasians and there is not a satisfactory explanation for this discrepancy.
Heart Rate Variability (HRV) has been demonstrated to reflect the relative activities of the sympathetic (SMP) and parasympathetic (PSMP) divisions of the autonomic nervous system (ANS).
This study consisted in comparing the HRV, as well as the blood pressure (BP) of four different groups during up-right tilt table testing. The subjects were grouped by age, gender, race and health condition. Analysis in time and frequency domain was applied to the data. In the frequency domain, the LF and HF bands were studied. In the time domain, a new parameter was proposed to analyze the data. As a result, the ratio of the FIF area, from the supine to the standing positions, was higher in the hypertensive group than the normotensive one, and the ratio of the LF area was higher in the normotensives than the others. On the other hand, Afro-Americans had a higher LF area ratio than Caucasians and a lower HF area ratio
Pulse respiration quotient as a measure sensitive to changes in dynamic behavior of cardiorespiratory coupling such as body posture and breathing regime
In this research we explored the (homeo)dynamic character of cardiorespiratory coupling (CRC) under the influence of different body posture and breathing regimes. Our tool for it was the pulse respiration quotient (PRQ), representing the number of heartbeat intervals per breathing cycle. We obtained non-integer PRQ values using our advanced Matlab® algorithm and applied it on the signals of 20 healthy subjects in four conditions: supine position with spontaneous breathing (Supin), standing with spontaneous breathing (Stand), supine position with slow (0.1 Hz) breathing (Supin01) and standing with slow (0.1 Hz) breathing (Stand01).Main results: Linear features of CRC (in PRQ signals) were dynamically very sensitive to posture and breathing rhythm perturbations. There are obvious increases in PRQ mean level and variability under the separated and joined influence of orthostasis and slow (0.1 Hz) breathing. This increase was most pronounced in Stand01 as the state of joint influences. Importantly, PRQ dynamic modification showed greater sensitivity to body posture and breathing regime changes than mean value and standard deviation of heart rhythm and breathing rhythm. In addition, as a consequence of prolonged supine position, we noticed the tendency to integer quantization of PRQ (especially after 14 min), in which the most common quantization number was 4:1 (demonstrated in other research reports as well). In orthostasis and slow breathing, quantization can also be observed, but shifted to other values. We postulate that these results manifest resonance effects induced by coupling patterns from sympathetic and parasympathetic adjustments (with the second as dominant factor).Significance: Our research confirms that cardiorespiratory coupling adaptability could be profoundly explored by precisely calculated PRQ parameter since cardiorespiratory regulation in healthy subjects is characterized by a high level of autonomic adaptability (responsiveness) to posture and breathing regime, although comparisons with pathological states has yet to be performed. We found Stand01 to be the most provoking state for the dynamic modification of PRQ (cardiorespiratory inducement). As such, Stand01 has the potential of using for PRQ tuning by conditioning the cardiorespiratory autonomic neural networks, e.g., in the cases where PRQ is disturbed by environmental (i.e., microgravity) or pathologic conditions
Heart rate variability in heart failure.
by Yeung Yuk-Ching.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 119-129).Abstracts in English and Chinese.Abstract in English --- p.iiAbstract in Chinese --- p.vGlossary --- p.viiiAcknowledgements --- p.xPublications Arising From this Thesis --- p.xiiList of Tables --- p.xviiiList of Figures --- p.xixChapter 1 --- INTRODUCTION --- p.1Chapter 1.1 --- Definition of Heart Rate Variability --- p.1Chapter 1.2 --- Physiology --- p.1Chapter 1.2.1 --- Review of Autonomic Nervous System and Influence of Heart Rate --- p.1Chapter 1.2.2 --- The Role of Baroreceptors in the Control of Circulation --- p.4Chapter 1.2.3 --- The Control and Physiological Importance of Heart Rate --- p.7Chapter 1.2.3.1 --- Normal Heart Rate --- p.7Chapter 1.2.3.2 --- Autonomic Control of Heart Rate --- p.8Chapter 1.2.3.2.1 --- Sympathetic Effects --- p.8Chapter 1.2.3.2.2 --- Vagal Effects --- p.8Chapter 1.2.3.3 --- Reflexes Influencing Heart Rate --- p.9Chapter 1.2.3.3.1 --- Baroreceptors --- p.10Chapter 1.2.3.3.2 --- Chemoreceptors --- p.10Chapter 1.2.3.3.3 --- Atrial Receptors --- p.11Chapter 1.2.3.3.4 --- Coronary Chemoreflex --- p.11Chapter 1.2.3.3.5 --- Other Reflexes --- p.12Chapter 1.2.3.4 --- Influence of Complex Events on Heart Rate --- p.12Chapter 1.2.3.4.1 --- Respiratory Influence --- p.12Chapter 1.2.3.4.2 --- Effects of Decreases in Venous Return --- p.13Chapter 1.2.3.4.3 --- Exercise --- p.13Chapter 1.2.3.5 --- Physiological Importance of Heart Rate --- p.14Chapter 1.3 --- Spectral Analysis of Blood Pressure and Heart Rate Variability in Evaluating Cardiovascular Regulation --- p.14Chapter 1.4 --- Clinical Relevance --- p.15Chapter 1.4.1 --- Increased Sympathetic Activity --- p.15Chapter 1.4.2 --- Reduced Parasympathetic Activity --- p.15Chapter 1.4.3 --- Low Heart Rate Variability --- p.16Chapter 1.4.4 --- Depressed Baroreflex Sensitivity --- p.17Chapter 1.4.5 --- Prognostic Value of Heart Rate Variability in Disease States --- p.17Chapter 1.4.6 --- Abnormality of Autonomic Nervous System in Heart Failure --- p.17Chapter 2 --- METHODS FOR ASSESSING HEART RATE VARIABILITY --- p.20Chapter 2.1 --- Time Domain Analysis of Heart Rate Variability --- p.20Chapter 2.1.1 --- Statistical Methods --- p.21Chapter 2.1.2 --- Geometric Methods --- p.22Chapter 2.2 --- Spectral Analysis of Heart Rate Variability --- p.23Chapter 2.3 --- "Nonlinear Indices (fractal, entropy, chaos theory)" --- p.27Chapter 3 --- HEART FAILURE --- p.28Chapter 3.1 --- Heart Rate Variability in Heart Failure --- p.28Chapter 3.2 --- Effect of Changes in Respiratory Frequency and Posture on Heart Rate Variability Analysis in Heart Failure --- p.34Chapter 3.3 --- Effect of Respiratory Rates on Baroreceptor Function in Heart Failure --- p.34Chapter 3.4 --- Effect of Treatment on Heart Rate Variability in Heart Failure Patients --- p.35Chapter 4 --- AIMS --- p.39Chapter 4.1 --- Effect of Changes in Respiratory Frequency and Posture on Heart Rate Variability --- p.39Chapter 4.2 --- Effect of Slow Breathing --- p.39Chapter 4.3 --- Effect of Therapeutic Interventions in Chronic Heart Failure --- p.39Chapter 4.3.1 --- A Comparison of Celiprolol with Metoprolol --- p.39Chapter 4.3.2 --- A Comparison of Carvedilol with Metoprolol --- p.40Chapter 5 --- STUDIES --- p.41Chapter 5.1 --- Impact of Changes in Respiratory Frequency and Posture on Power Spectral Analysis of Heart Rate and Systolic Blood Pressure Variability in Normal Subjects and Patients with Heart Failure --- p.41Chapter 5.1.1 --- Subjects --- p.41Chapter 5.1.2 --- Recording Technique and Protocol --- p.42Chapter 5.1.3 --- Signal Acquisition --- p.42Chapter 5.1.4 --- Power Spectral Analysis --- p.43Chapter 5.1.5 --- Statistical Analysis --- p.46Chapter 5.1.6 --- Results --- p.46Chapter 5.1.7 --- Discussion --- p.52Chapter 5.1.8 --- Summary --- p.56Chapter 5.2 --- Slow Breathing Increases Arterial Baroreflex Sensitivityin Patients with Chronic Heart Failure --- p.57Chapter 5.2.1 --- Subjects --- p.57Chapter 5.2.2 --- Assessment of Baroreflex Sensitivity --- p.57Chapter 5.2.3 --- Statistical Analysis --- p.58Chapter 5.2.4 --- Results --- p.59Chapter 5.2.5 --- Discussion --- p.62Chapter 5.2.6 --- Summary --- p.63Chapter 5.3 --- β-Blockers in Heart Failure: a Comparison of a Vasodilating β- Blocker with Metoprolol on Heart Rate Variability by 24 Hour ECG Recordings (Time-Domain & Spectral Analysis) --- p.65Chapter 5.3.1 --- Trial Design --- p.65Chapter 5.3.2 --- Study Patients --- p.65Chapter 5.3.3 --- Study Measurements --- p.66Chapter 5.3.4 --- Statistical Analysis --- p.67Chapter 5.3.5 --- Results --- p.67Chapter 5.3.6 --- Discussion --- p.80Chapter 5.3.7 --- Summary --- p.81Chapter 5.4 --- Effect of β-Blockade on Baroreceptor and Autonomic Function in Heart Failure-Assessment by Short Term Spectral Analysis --- p.83Chapter 5.4.1 --- Trial Design and Study Patients --- p.83Chapter 5.4.2 --- Recording Technique and Protocol --- p.83Chapter 5.4.3 --- "Signal Acquisition, Power Spectral Analysis and Cross Spectral Analysis" --- p.83Chapter 5.4.4 --- Reproducibility --- p.84Chapter 5.4.5 --- Statistical Analysis --- p.84Chapter 5.4.6 --- Results --- p.84Chapter 5.4.7 --- Discussion --- p.93Chapter 5.4.8 --- Summary --- p.97Chapter 5.5 --- β-Blockade in Heart Failure: A Comparison of Carvedilol with Metoprolol on HRV by 24 hour ECG Recordings (Time-Domain & Spectral Analysis) --- p.98Chapter 5.5.1 --- Trial Design and Patient Demographics --- p.98Chapter 5.5.2 --- Study Measurements --- p.98Chapter 5.5.3 --- Statistical Analysis --- p.99Chapter 5.5.4 --- Results --- p.99Chapter 5.5.5 --- Discussion --- p.105Chapter 5.5.6 --- Conclusions --- p.107Chapter 5.6 --- Comparison of Carvedilol and Metoprolol on Baroreceptor Gain in Heart Failure by Short Term Spectral Analysis --- p.108Chapter 5.6.1 --- Study Design --- p.108Chapter 5.6.2 --- Study Patients --- p.108Chapter 5.6.3 --- Recording Technique and Protocol --- p.108Chapter 5.6.4 --- "Signal Acquisition, Power Spectral Analysis and Cross Spectral Analysis" --- p.108Chapter 5.6.5 --- Statistical Analysis --- p.109Chapter 5.6.6 --- Results --- p.109Chapter 5.6.7 --- Discussion --- p.112Chapter 5.6.8 --- Summary --- p.112Chapter 6 --- "GENERAL DISCUSSION, LIMITATIONS & CONCLUSIONS" --- p.113Chapter 6.1 --- Discussion --- p.113Chapter 6.2 --- Conclusions --- p.117Chapter 7 --- REFERENCES --- p.11
Effects of Thoracic Spine Position during Cycle Sprint Recovery
There is a paucity of research on how to recover during a race or practice immediately between cycling sprints. The subjects of this study included 13 competitive male cyclists recruited from local bicycle shops. This study utilized a pretest-posttest experimental design. Participants completed two 30-s maximal effort sprints on a cycle ergometer followed by two four-min active recovery intervals. They were randomly assigned to either a flexed thoracic spine position greater than 14° (FC) or a neutral thoracic spine position (NC) during cycling sprint recovery intervals on the first testing day and completed the other no less than 48 hours later. Recorded variables included heart rate recovery (HRR), tidal volume (VT), carbon dioxide output (VCO2), change in sprint mean power (ΔMP), and change in sprint fatigue index (ΔFI). There were no significant differences between conditions in any of the variables (p\u3e0.05). Using the Cohen’s d statistic, there was a small effect of thoracic spine position during recovery on HRR (p=0.293; d=0.33), VT (p=0.121; d=0.34), and ΔFI (p=0.289; d=0.45) from one sprint to another. However, there was no effect of thoracic position on VCO2 (p=0.794; d=0.062) or the ΔMP (p=0.853; d=0.051) from sprint to sprint. HRR was 23.5±0.40 bpm in FC and 21.3±5.0 bpm in NC. VT was 3.0±0.51 L in FC and 3.19±0.54 L in NC. VCO2 was 3.28±0.25 L/min in FC and 3.26±3.61 L/min in NC. ΔMP was -29.7±17 W in FC and -28.8±19 W in NC. ΔFI was 0.59±3.6 W/s in FC and -0.429±1.9 L in NC. There may be little to no benefit in assuming a more flexed thoracic position between cycling sprints
Central and Peripheral Chemoreflex Function in the Supine and Upright Postures in Women throughout the Menstrual Cycle with a Comparison to Men
The primary purpose of the study was to examine sex differences and menstrual cycle time-points on chemoreflex function during supine and 70o upright (HUT) positions during: 1) normoxia, 2) hypercapnia (5% CO2), or 3) hyperoxia (100% O2). Women were tested during the early-follicular phase (EF; days 2-5) and the mid-luteal phase (ML; days 18-24). Compared to baseline, men and women had lower cardiac output index (Qi), mean arterial pressure (MAP), cerebrovascular resistance index, and respiratory rate during HUT. In response to hypercapnia during HUT (compared to supine), men had an augmented increase in MAP, while all groups had an augmented increase in ventilation suggesting sexually dimorphic interactions between the baroreflex and central chemoreflex. In response to hyperoxia during HUT, men and women displayed an attenuated increase of total peripheral resistance index and an attenuated decrease of Qi suggesting upright posture activated peripheral chemoreceptors
Heart Rate Variability In Collegiate Division I Athletes
M.S. Thesis. University of Hawaiʻi at Mānoa 2017
Validity of Telemetric-Derived Measures of Heart Rate Variability : A Systematic Review
Validity of Telemetric-Derived Measures of Heart Rate Variability: A Systematic Review. JEPonline 2016;19(6):64-84. Heart rate variability (HRV) is a widely accepted indirect measure of autonomic function with widespread application across many settings. Although traditionally measured from the ‘gold standard’ criterion electrocardiography (ECG), the development of wireless telemetric heart rate monitors (HRMs) extends the scope of the HRV measurement. However, the validity of telemetric-derived data against the criterion ECG data is unclear. Thus, the purpose of this study was twofold: (a) to systematically review the validity of telemetric HRM devices to detect inter-beat intervals and aberrant beats; and (b) to determine the accuracy of HRV parameters computed from HRM-derived inter-beat interval time series data against criterion ECG-derived data in healthy adults aged 19 to 62 yrs. A systematic review of research evidence was conducted. Four electronic databases were accessed to obtain relevant articles (PubMed, EMBASE, MEDLINE and SPORTDiscus. Articles published in English between 1996 and 2016 were eligible for inclusion. Outcome measures included temporal and power spectral indices (Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (1996). The review confirmed that modern HRMs (Polar® V800™ and Polar® RS800CX™) accurately detected inter-beat interval time-series data. The HRV parameters computed from the HRM-derived time series data were interchangeable with the ECG-derived data. The accuracy of the automatic in-built manufacturer error detection and the HRV algorithms were not established. Notwithstanding acknowledged limitations (a single reviewer, language bias, and the restricted selection of HRV parameters), we conclude that the modern Polar® HRMs offer a valid useful alternative to the ECG for the acquisition of inter-beat interval time series data, and the HRV parameters computed from Polar® HRM-derived inter-beat interval time series data accurately reflect ECG-derived HRV metrics, when inter-beat interval data are processed and analyzed using identical protocols, validated algorithms and software, particularly under controlled and stable conditions
Validity of Telemetric-Derived Measures of Heart Rate Variability: A Systematic Review
Heart rate variability (HRV) is a widely accepted indirect measure of autonomic function with widespread application across many settings. Although traditionally measured from the ‘gold standard’ criterion electrocardiography (ECG), the development of wireless telemetric heart rate monitors (HRMs) extends the scope of the HRV measurement. However, the validity of telemetric-derived data against the criterion ECG data is unclear. Thus, the purpose of this study was twofold: (a) to systematically review the validity of telemetric HRM devices to detect inter-beat intervals and aberrant beats; and (b) to determine the accuracy of HRV parameters computed from HRM-derived inter-beat interval time series data against criterion ECG-derived data in healthy adults aged 19 to 62 yrs. A systematic review of research evidence was conducted. Four electronic databases were accessed to obtain relevant articles (PubMed, EMBASE, MEDLINE and SPORTDiscus. Articles published in English between 1996 and 2016 were eligible for inclusion. Outcome measures included temporal and power spectral indices (Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (1996). The review confirmed that modern HRMs (Polar® V800™ and Polar® RS800CX™) accurately detected inter-beat interval time-series data. The HRV parameters computed from the HRM-derived time series data were interchangeable with the ECG-derived data. The accuracy of the automatic in-built manufacturer error detection and the HRV algorithms were not established. Notwithstanding acknowledged limitations (a single reviewer, language bias, and the restricted selection of HRV parameters), we conclude that the modern Polar® HRMs offer a valid useful alternative to the ECG for the acquisition of inter-beat interval time series data, and the HRV parameters computed from Polar® HRM-derived inter-beat interval time series data accurately reflect ECG-derived HRV metrics, when inter-beat interval data are processed and analyzed using identical protocols, validated algorithms and software, particularly under controlled and stable conditions
Optimizing Chronic Slow Breathing Training to Cause a Therapeutic Effect on Heart Rate Variability
Heart rate variability (HRV) is a valid and reliable tool that can be used to determine the basic state of an individual\u27s autonomic health. The current study attempted to establish the minimum frequency of breathing practice necessary to produce a therapeutic effect on HRV over the course of a four-week period with four different treatment groups, specifically, groups that practiced a slow breathing protocol for either 2, 3 or 5 times per week, and a control group. Forty-three subjects (14 males, 29 females), ages 18–50 years, were screened, pre-tested, matched for sex, age and HRV, assigned to a specific group for a four-week training period, and completed the study. All pre- and post-test measurements were made during a 10-minute period of supine rest, and included systolic and diastolic blood pressure (BP), heart rate (HR), and the following HRV measures: standard deviation of the normal to normal R waves (SDNN), root mean square of successive differences (RMSSD), high frequency power (HF), low frequency power (LF), and HF/LF ratio. During the 4-week training period, subjects kept a log of their breathing training and then returned for post-testing of the same variables. A two-way analysis of variance with repeated measures on one factor and post hoc T-tests were used to evaluate the data. Significance was set at the 0.05 level. Following the 4-week training period, the control group experienced an increase in systolic BP, while all three training groups experienced a decrease. For diastolic BP, the control group experienced an increase, while only the 2 times per week training group experienced a decrease. For HR, the 2 times per week and 5 times per week groups demonstrated a decrease, while no other groups changed. There were no differences in any HRV measures as a result of training in any group. In conclusion, although previous research had found that breathing training affected HRV measures, there was no effect in this study regardless of the frequency of training. Breathing training did cause a reduction in resting BP and heart rate, but the frequency of training had little to no differential effect. The study was unable to demonstrate a minimum frequency of breathing training for affecting the autonomic nervous system
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