Showing papers on "Heart rate variability published in 2012"
TL;DR: A meta-analysis of recent neuroimaging studies on the relationship between heart rate variability and regional cerebral blood flow identified a number of regions, including the amygdala and ventromedial prefrontal cortex, in which significant associations across studies were found.
2,174 citations
TL;DR: Evidence suggests that HRV collected during a PSG can be used in risk stratification models, at least for older adults, and a novel HRV measure, cardiopulmonary coupling, has been proposed for sleep quality.
359 citations
TL;DR: The potential for HRV to be used widely in clinical practice remains to be established, and analyses of HRV variables have been proposed as a component of the clinical evaluation for patient risk stratification due to its independent prognostic information.
328 citations
TL;DR: The data suggests that increased HRV may provide a novel marker of one's ability to recognize emotions in humans, and implications for understanding the biological basis of emotion recognition, and social impairment in humans are discussed.
288 citations
TL;DR: This study aimed to investigate epilepsy and its treatment impact on heart rate variability (HRV), assessed by sympathetic and parasympathetic activity expressed as low‐frequency (LF) and high-frequency (HF) power spectrum, respectively.
Abstract: Summary
Purpose: Epilepsy is associated with near-fatal and fatal arrhythmias, and sudden unexpected death in epilepsy (SUDEP) is partly related to cardiac events. Dysfunction of the autonomous nervous system causes arrhythmias and, although previous studies have investigated the effects of epilepsy on the autonomic control of the heart, the results are still mixed regarding whether imbalance of sympathetic, vagal, or both systems is present in epilepsy, and also the importance of anticonvulsant treatment on the autonomic system. Therefore, we aimed to investigate epilepsy and its treatment impact on heart rate variability (HRV), assessed by sympathetic and parasympathetic activity expressed as low-frequency (LF) and high-frequency (HF) power spectrum, respectively.
Method: We performed a systematic review from the first date available to July 2011 in Medline and other databases; key search terms were “epilepsy”; “anticonvulsants”; “heart rate variability”; “vagal”; and “autonomous nervous system.” Original studies that reported data and/or statistics of at least one HRV value were included, with data being extracted by two independent authors. We used a random-effects model with Hedges’s g as the measurement of effect size to perform two main meta-analyses comparing LF and HF HRV values in (1) epilepsy patients versus controls; (2) patients receiving versus not receiving treatment; and (3) well-controlled versus refractory patients. Secondary analyses assessed other time- and frequency-domain measurements (nonlinear methods were not analyzed due to lack of sufficient data sets). Quality assessment of each study was verified and also meta-analytic techniques to identify and control bias. Meta-regression for age and gender was performed.
Key Findings: Initially, 366 references were identified. According to our eligibility criteria, 30 references (39 studies) were included in our analysis. Regarding HF, epilepsy patients presented lower values (g −0.69) than controls, with the 95% confidence interval (CI) ranging from −1.05 to −0.33. No significant differences were observed for LF (g −0.18; 95% CI −0.71 to 0.35). Patients receiving treatment presented HF values to those not receiving treatment (g −0.05; 95% CI −0.37 to 0.27), with a trend for having higher LF values (g 0.1; 95% CI −0.13 to 0.33), which was more pronounced in those receiving antiepileptic drugs (vs. vagus nerve stimulation). No differences were observed for well-controlled versus refractory patients, possibly due to the low number of studies. Regression for age and gender did not influence the results. Finally, secondary time-domain analyses also showed lower HRV and lower vagal activity in patients with epilepsy, as shown by the standard deviation of normal-to-normal interval (SDNN) and the root mean square of successive differences (RMSSD) indexes, respectively.
Significance: We confirmed and extended the hypothesis of sympathovagal imbalance in epilepsy, as showed by lower HF, SDNN, and RMSSD values when compared to controls. In addition, there was a trend for higher LF values in patients receiving pharmacotherapy. As lower vagal (HF) and higher sympathetic (LF) tone are predictors of morbidity and mortality in cardiovascular samples, our findings highlight the importance of investigating autonomic function in patients with epilepsy in clinical practice. Assessing HRV might also be useful when planning therapeutic interventions, as some antiepileptic drugs can show hazardous effects in cardiac excitability, potentially leading to cardiac arrhythmia.
257 citations
TL;DR: The results demonstrate that even under normal, i.e., neither sleep nor light deprived conditions, more intense light can improve feelings of alertness and vitality, as well as objective performance and physiological arousal.
255 citations
TL;DR: This paper reviews the methods used for editing of the R–R interval time series and how this editing can influence the results of heart rate (HR) variability analyses, and summarizes the pre-processing methods for HR variability signal.
Abstract: Measurement of the heart rate (HR) variability from short and long-term electrocardiographic (ECG) recordings is a non-invasive method, which can used be as a tool to evaluate cardiac autonomic regulation. HR variability can give information about the sympathetic-parasympathetic autonomic balance. One important clinical application is to measure HR variability from patients suffering acute myocardial infarction (AMI). However, HR variability signals, R-R interval time series obtained from ambulatory ECG recordings contain in most of the cases different amount of artefacts. Artefacts appear due to disturbances of either physiological or technical origin. For instance, technical artefacts may result from poorly fastened electrodes or be due to motion artefacts. Ectopic beats and atrial fibrillation are examples of biological artefacts. Since the ectopic beats and other artifacts are common phenomena in the R-R interval time series, they make a reliable analysis of the HR variability difficult or even impossible. In conjunction with the increased usage of HR variability analyses, various studies have confirmed the need of different approaches to handle artefacts in the R-R interval time series. The editing process of the R-R interval time series has become an important part of the HR variability analysis. Several different editing and HR variability signal preprocessing methods have been introduced and tested for the artefact correction. Artifact correction can be performed with different methods such as deletion, various interpolation methods and different filtering systems. However, different editing methods can have different effects on the HR variability measures. The effects of editing is depended on the study setting including the editing method, HR variability measure, type of study population, length of the R-R interval time series.
220 citations
TL;DR: In this paper, the authors show that reduced central sympathetic inhibition may be the exception rather than the rule after renal nerve ablation in unselected patients with difficult-to-control arterial hypertension.
Abstract: Endovascular renal nerve ablation has been developed to treat resistant hypertension. In addition to lowering efferent renal sympathetic activation, the intervention may attenuate central sympathetic outflow through decreased renal afferent nerve traffic, as evidenced by a recent case report. We tested the hypothesis in 12 nonpreselected patients with difficult-to-control hypertension (aged 45-74 years) admitted for renal nerve ablation. All patients received ≥ 3 antihypertensive medications at full doses, including a diuretic. Electrocardiogram, respiration, brachial and finger arterial blood pressure, and muscle sympathetic nerve activity were recorded before and 3 to 6 months after renal nerve ablation. Heart rate and blood pressure variability were analyzed in the time and frequency domain. Pharmacological baroreflex slopes were determined using the modified Oxford bolus technique. Resting heart rate was 61 ± 3 bpm before and 58 ± 2 bpm after ablation (P = 0.4). Supine blood pressure was 157 ± 7/85 ± 4 mm Hg before and 157 ± 6/85 ± 4 mm Hg after ablation (P = 1.0). Renal nerve ablation did not change resting muscle sympathetic nerve activity (before, 34 ± 2 bursts per minute; after, 32 ± 3 bursts per minute P = 0.6), heart rate variability, or blood pressure variability. Pharmacological baroreflex control of heart rate and muscle sympathetic nerve activity did not change. We conclude that reduced central sympathetic inhibition may be the exception rather than the rule after renal nerve ablation in unselected patients with difficult-to-control arterial hypertension.
186 citations
TL;DR: Exercise and antidepressant medication resulted in greater reductions in depressive symptoms compared to placebo in patients with coronary heart disease and evidence that active treatments may also improve cardiovascular biomarkers suggests that they may have a beneficial effect on clinical outcomes as well as on quality of life.
185 citations
TL;DR: The meta-analysis supports an inverse relationship between HRV, a marker for a worse cardiovascular prognosis, and particulate air pollution.
Abstract: Objective Studies on the association between short-term exposure to ambient air pollution and heart rate variability (HRV) suggest that particulate matter (PM) exposure is associated with reductions in measures of HRV, but there is heterogeneity in the nature and magnitude of this association between studies. The authors performed a meta-analysis to determine how consistent this association is. Data source The authors searched the Pubmed citation database and Web of Knowledge to identify studies on HRV and PM. Study selection Of the epidemiologic studies reviewed, 29 provided sufficient details to be considered. The meta-analysis included 18667 subjects recruited from the population in surveys, studies from patient groups, and from occupationally exposed groups. Data extraction Two investigators read all papers and computerised all relevant information. Results The authors computed pooled estimates from a random-effects model. In the combined studies, an increase of 10 μg/m 3 in PM 2.5 was associated with significant reductions in the time-domain measurements, including low frequency (−1.66%, 95% CI −2.58% to −0.74%) and high frequency (−2.44%, 95% CI −3.76% to −1.12%) and in frequency-domain measurements, for SDNN (−0.12%, 95% CI −0.22% to −0.03%) and for rMSSD (−2.18%, 95% CI −3.33% to −1.03%). Funnel plots suggested that no publication bias was present and a sensitivity analysis confirmed the robustness of our combined estimates. Conclusion The meta-analysis supports an inverse relationship between HRV, a marker for a worse cardiovascular prognosis, and particulate air pollution.
153 citations
TL;DR: The results show good reliability of indices reflecting central parasympathetic control over heart rate and that about 40% of the variance of a single HRV measurement can be explained by effects of the situation and person-situation interaction.
Abstract: Heart rate variability (HRV) is a measure of autonomic influences on heart rate that has frequently been used as a transsituationally consistent biomarker for cardiovascular health and emotional or cognitive functions. The psychometric properties of HRV however remain unclear. In the present study, we examined the reliability and temporal stability of parasympathetic HRV measures and estimated the portion of variance explained by transsituationally consistent trait variance and by effects of the situation and person-situation interaction with structural equation modeling. The results show good reliability of indices reflecting central parasympathetic control over heart rate and that about 40% of the variance of a single HRV measurement can be explained by effects of the situation and person-situation interaction. An aggregation across at least two measurements may be recommended when using HRV as a transsituationally consistent biomarker or trait.
TL;DR: It is suggested that intranasal administration of OT may ameliorate some symptoms of social anxiety in patients with FXS and further double-blind placebo-controlled studies of OT, conducted in combination with behavioral treatment programs, may be warranted.
TL;DR: The MMA method is introduced, which allows the description of heart rate variability to include the dependence on the magnitude of the variability and time scale (or frequency band), and it may provide new ways of measuring the nonlinearity of a signal.
Abstract: Human heart rate variability, in the form of time series of intervals between heart beats, shows complex, fractal properties. Recently, it was demonstrated many times that the fractal properties vary from point to point along the series, leading to multifractality. In this paper, we concentrate not only on the fact that the human heart rate has multifractal properties but also that these properties depend on the time scale in which the multifractality is measured. This time scale is related to the frequency band of the signal. We find that human heart rate variability appears to be far more complex than hitherto reported in the studies using a fixed time scale. We introduce a method called multiscale multifractal analysis (MMA), which allows us to extend the description of heart rate variability to include the dependence on the magnitude of the variability and time scale (or frequency band). MMA is relatively immune to additive noise and nonstationarity, including the nonstationarity due to inclusions into the time series of events of a different dynamics (e.g., arrhythmic events in sinus rhythm). The MMA method may provide new ways of measuring the nonlinearity of a signal, and it may help to develop new methods of medical diagnostics.
TL;DR: Evidence is provided that autonomic control of the heart is altered by the simple act of just viewing natural scenes with an increase in vagal activity, and heart rate variability was used to investigate alterations in autonomic activity.
Abstract: Previously studies have shown that nature improves mood and self-esteem and reduces blood pressure. Walking within a natural environment has been suggested to alter autonomic nervous system control, but the mechanisms are not fully understood. Heart rate variability (HRV) is a non-invasive method of assessing autonomic control and can give an insight into vagal modulation. Our hypothesis was that viewing nature alone within a controlled laboratory environment would induce higher levels of HRV as compared to built scenes. Heart rate (HR) and blood pressure (BP) were measured during viewing different scenes in a controlled environment. HRV was used to investigate alterations in autonomic activity, specifically parasympathetic activity. Each participant lay in the semi-supine position in a laboratory while we recorded 5 min (n = 29) of ECG, BP and respiration as they viewed two collections of slides (one containing nature views and the other built scenes). During viewing of nature, markers of parasympathetic activity were increased in both studies. Root mean squared of successive differences increased 4.2 ± 7.7 ms (t = 2.9, p = 0.008) and natural logarithm of high frequency increased 0.19 ± 0.36 ms2 Hz−1 (t = 2.9, p = 0.007) as compared to built scenes. Mean HR and BP were not significantly altered. This study provides evidence that autonomic control of the heart is altered by the simple act of just viewing natural scenes with an increase in vagal activity.
TL;DR: The finding that gender differences are limited to adolescent and adult age groups may indicate a role for female sex hormones in cardiac autonomic modulation.
Abstract: Ageing is associated with changes in cardiac autonomic control as measured by Heart Rate Variability (HRV). Not many studies have explored the influence of gender on age-related changes in cardiac autonomic regulation. This study evaluated the gender differences in age-associated changes in cardiac autonomic nervous activity by assessing HRV using frequency domain analysis of short-term stationary R-R intervals. HRV was studied in healthy males and females ranging in age from 6 to 55 years. Total power and absolute power in High-Frequency (HF) and Low-Frequency (LF) components as well as HF in normalized unit declined significantly with ageing. The HF/LF ratio was significantly higher in the adolescent and adult females compared to male of these age groups. This study suggests that gender differences exist in age-related changes in HRV. The finding that gender differences are limited to adolescent and adult age groups may indicate a role for female sex hormones in cardiac autonomic modulation.
TL;DR: HRV measures could potentially be used to predict when an individual is at increased risk of attentional failure, and could be incorporated into safety devices to warn drowsy operators when their performance is impaired.
Abstract: Study objectives To assess whether changes in psychomotor vigilance during sleep deprivation can be estimated using heart rate variability (HRV). Design HRV, ocular, and electroencephalogram (EEG) measures were compared for their ability to predict lapses on the Psychomotor Vigilance Task (PVT). Setting Chronobiology and Sleep Laboratory, Duke-NUS Graduate Medical School Singapore. Participants Twenty-four healthy Chinese men (mean age ± SD = 25.9 ± 2.8 years). Interventions Subjects were kept awake continuously for 40 hours under constant environmental conditions. Every 2 hours, subjects completed a 10-minute PVT to assess their ability to sustain visual attention. Measurements and results During each PVT, we examined the electrocardiogram (ECG), EEG, and percentage of time that the eyes were closed (PERCLOS). Similar to EEG power density and PERCLOS measures, the time course of ECG RR-interval power density in the 0.02-0.08-Hz range correlated with the 40-hour profile of PVT lapses. Based on receiver operating characteristic curves, RR-interval power density performed as well as EEG power density at identifying a sleepiness-related increase in PVT lapses above threshold. RR-interval power density (0.02-0.08 Hz) also classified subject performance with sensitivity and specificity similar to that of PERCLOS. Conclusions The ECG carries information about a person's vigilance state. Hence, HRV measures could potentially be used to predict when an individual is at increased risk of attentional failure. Our results suggest that HRV monitoring, either alone or in combination with other physiologic measures, could be incorporated into safety devices to warn drowsy operators when their performance is impaired.
17 Oct 2012
TL;DR: Heart rate Variability: A Historical Perspective Markad V. Kamath, Mari A. Watanabe, and Adrian R.M. Upton Section I Heart Rate Variability Techniques Methodological Aspects of Heart Ratevariability Analysis Tom Kuusela MethodologicalAspects of Baroreflex Sensitivity Analysis TomKuuselA Arterial Blood Pressure Waveform Analysis and Its Applications in the Assessment of Vasovagal Syncope
Abstract: Heart Rate Variability: A Historical Perspective Markad V. Kamath, Mari A. Watanabe, and Adrian R.M. Upton Section I Heart Rate Variability Techniques Methodological Aspects of Heart Rate Variability Analysis Tom Kuusela Methodological Aspects of Baroreflex Sensitivity Analysis Tom Kuusela Arterial Blood Pressure Waveform Analysis and Its Applications in the Assessment of Vasovagal Syncope Juan Carlos Perfetto, Ricardo O. Sirne, Aurora Ruiz, and Carlos E. D'Attellis Heart Rate Turbulence Mari A. Watanabe and Georg Schmidt Phase-Rectified Signal Averaging: Methods and Clinical Applications Raphael Schneider, Alexander Muller, and Georg Schmidt Section II Clinical Applications of Heart Rate Variability-Monitoring Heart Rate Variability Analysis for the Monitoring of Fetal Distress and Neonatal Critical Care Manuela Ferrario, Federico Aletti, Giuseppe Baselli, Maria Gabriella Signorini, and Sergio Cerutti Heart Rate Variability and Blood Pressure Variability in Obstetrics and Gynecology Dietmar Schlembach and Manfred G. Moertl Effects of Exercise Training on Heart Rate Variability in Patients with Hypertension Philip J. Millar, Cheri L. McGowan, and Neil McCartney Heart Rate Variability and Sleep Eleonora Tobaldini, Krzystof Narkiewicz, Virend K. Somers, and Nicola Montano Section III Clinical Applications of Heart Rate Variability-Acute Care Heart Rate Variability in the Intensive Care Unit Mohammad Badrul Alam, Graham Jones, Andrew J.E. Seely, W.F.S. Poehlman, and Markad V. Kamath Heart Rate Variability and Cardiovascular Dynamic Changes during Local Anesthesia Panayiotis A. Kyriacou and Kamran Shafqat Effect of General Anesthesia on Heart Rate Variability Mathieu Jeanne, Regis Logier, and Benoit Tavernier Heart Rate Variability in Functional Neurosurgery Jonathan A. Hyam, Erlick A.C. Pereira, and Alexander L. Green Bariatric Surgery and Its Effects on Heart Rate Variability Anton F. Lodder, Markad V. Kamath, David Armstrong, and Adrian R.M. Upton Section IV Clinical Applications of Heart Rate Variability-Chronic Disorders Heart Rate Variability in Congestive Heart Failure Phyllis K. Stein and Yachuan Pu Heart Rate Variability Analysis in Ischemic Cardiomyopathy and Aortic Stenosis Patients Jose F. Valencia, Montserrat Vallverdu, Alberto Porta, Andreas Voss, Rafael Vazquez, and Pere Caminal Heart Rate Variability and Blood Pressure Variability in Respiratory Disease: Effects of Pharmaceutical Compounds, Non-Invasive Ventilation and Physical Exercise Audrey Borghi Silva and Aparecida Maria Catai Effects of Spinal Cord Injury on Heart Rate Variability and Blood Pressure Variability David S. Ditor, David Allison, and Markad V. Kamath Autonomic Dysfunction in Stroke Melanie I. Stuckey, Mikko Tulppo, and Robert J. Petrella The Significance of Heart Rate Variability in Patients with Epilepsy Manjari Tripathi and Navita Choudhary Classification of Parkinson's Disease Severity Using Heart Rate Variability Analysis Che-Wei Lin, Jeen-Shing Wang, Pau-Choo Chung, Chung-Yao Hsu, Li-Ming Liou, Yen-Kuang Yang, and Ya-Ting Yang Heart Rate Variability in Neuropsychiatric Disorders Brook L. Henry Heart Rate Variability and Depression Gautam R. Ullal Heart Rate Variability as a Measure of Depression and Anxiety during Pregnancy Alison K. Shea, Meir Steiner, and Markad V. Kamath Index
TL;DR: These effects suggest that HRV-BF, a novel behavioral neurocardiac intervention, could enhance BRS, improve the cardiac autonomic tone, and facilitate BP adjustment for individuals with prehypertension.
Abstract: Background: Individuals with prehypertension are at risk of hypertension and cardiovascular diseases, and yet efficient interventions are lagging behind. Studies indicate that heart rate variability–biofeedback (HRV-BF) increases HRV and baroreflex sensitivity (BRS) as well as reduces related pathological symptoms, suggesting potentially beneficial effects of HRV-BF on prehypertension, but little is known about these effects. In this study, these effects were investigated and their mechanisms were explored. Objectives: The effect of HRV-BF on prehypertension in young adults and its potential mechanism were explored. Design: Forty-three (43) individuals with prehypertension were recruited and classified into three categories: HRV-BF group, slow abdominal breathing group, and control group. All groups were assessed with measurements of noninvasive blood pressure (BP), BRS, respiration, and galvanic skin response (GSR) at pre-intervention, in the entire process of each session, at postintervention, ...
TL;DR: A significant main effect of sleep-wake–dependent and circadian processes on cardiac rhythmicity, as well as a significant interaction between these processes are revealed, contributing to the understanding of the observed increase in cardiovascular vulnerability after awakening in the morning.
Abstract: Morning hours are associated with a heightened risk of adverse cardiovascular events. Recent evidence suggests that the sleep-wake cycle and endogenous circadian system modulate cardiac function in humans and may contribute to these epidemiological findings. The aim of the present study was to investigate the interaction between circadian and sleep-wake–dependent processes on heart rate variability (HRV). Fifteen diurnally active healthy young adults underwent a 72-h ultradian sleep-wake cycle (USW) procedure (alternating 60-min wake episodes in dim light and 60-min nap opportunities in total darkness) in time isolation. The present study revealed a significant main effect of sleep-wake–dependent and circadian processes on cardiac rhythmicity, as well as a significant interaction between these processes. Turning the lights off was associated with a rapid increase in mean RR interval and cardiac parasympathetic modulation (high-frequency [HF] power), whereas low-frequency (LF) power and sympathovagal balan...
TL;DR: This article presents a methodology for analyzing the influence of CVI and CSI on heart rate variability spectral patterns—low-frequency and high-frequency spectral bands and LF/HF ratio and an adaptive neuro-fuzzy network is used to approximate correlation between these two features and spectral patterns.
Abstract: Heart rate signal can be used as certain indicator of heart disease. Spectral analysis of heart rate variability (HRV) signal makes it possible to partly separate the low-frequency (LF) sympathetic component, from the high-frequency (HF) vagal component of autonomic cardiac control. Here, we used two important features to characterize the nonlinear fluctuations in the heart variability signal (HRV): cardiac vagal index (CVI) and cardiac sympathetic index (CSI) which indicates vagal and sympathetic function separately. This article presents a methodology for analyzing the influence of CVI and CSI on heart rate variability spectral patterns—low-frequency (LF) and high-frequency (HF) spectral bands and LF/HF ratio. An adaptive neuro-fuzzy network is used to approximate correlation between these two features and spectral patterns. This system is capable to find any change in ratio of features and spectral patterns of heart rate variability signal (HRV) and thus indicates state of both parasympathetic and sympathetic functions in newly diagnosed patients with heart diseases.
TL;DR: Results of this study revealed that the heart rate and the changes in rates that occurred between different activity levels showed a significant increase during warm conditions, with a 2.5 metabolic rate, especially in males and in body mass index groups higher than 22.
TL;DR: This review considers studies on the prognostic value of HRV in elderly subjects, discussing the potential confounding effect of erratic rhythm, and concentrates on the conceptual distinction between autonomic tone and autonomic modulation.
Abstract: Heart rate variability (HRV) is the temporal beat-to-beat variation in successive RR intervals on an electrocardiographic (ECG) recording and it reflects the regulation of the heart rate (HR) by the autonomic nervous system (ANS) HRV analysis is a noninvasive tool for the assessment of autonomic function that gained momentum in the late 1980s when its clinical relevance as a predictor of mortality was established by a milestone study by Kleiger et al in patients with postacute myocardial infarction In the last few decades, the increasing availability of commercial ECG devices offering HRV analysis has made HRV a favorite marker for risk stratification in the setting of cardiovascular disease The rapid aging of the world population and the growing popularity of HRV have also fueled interest for the prognostic value of HRV in the elderly, outside a specific cardiological context However, the discussion of HRV measures in the elderly is still very much centered on the rather reductionistic model of sympathovagal balance, with the orthosympathetic and parasympathetic limbs of the ANS exercising opposing effects on the heart via autonomic tone The expanding application of nonlinear dynamics to medicine has brought to the forefront the notion of system complexity, embedded in the mathematical concepts of chaos theory and fractals, and provides an opportunity to suggest a broader interpretation for the prognostic significance of HRV, especially in the elderly Although the use of novel indices of HRV may be hampered by practical issues, a more holistic approach to HRV may still be safeguarded if traditional time- and frequency-domain measures are viewed in terms of autonomic modulation This review focuses on HRV in geriatric populations It considers studies on the prognostic value of HRV in elderly subjects, discussing the potential confounding effect of erratic rhythm, and concentrates on the conceptual distinction between autonomic tone and autonomic modulation It also briefly addresses the question of the practicality of ECG recordings and identifies a promising area for future research in the effects of common noncardioactive drugs on HRV
TL;DR: Cardiac autonomic imbalance correlates with the adipose tissue-derived inflammation seen early in type 2 diabetes and are interrelated.
Abstract: Introduction. Diabetics die from cardiovascular disease at a much greater rate than nondiabetics. Cardiac autonomic imbalance predicts increased cardiovascular risk and mortality. We studied the relationship between cardiac autonomic imbalance and adipose tissue-derived inflammation in newly diagnosed and established type 2 diabetes. Materials and Methods. Non-diabetics, newly diagnosed diabetics, and established diabetics were included. Anthropomorphic and biochemical measurements were obtained, and insulin resistance was approximated. Cardiac autonomic function was assessed using conventional measures and with power spectral analysis of heart rate. Results and Discussion. Heart rate variability was reduced in all diabetics. Interleukin-6 was higher in diabetics, as was the high molecular weight adiponectin-to-leptin ratio. Interleukin-6 correlated negatively with measures of autonomic balance. Ratios of adiponectin to leptin correlated positively with measures of autonomic balance. Cardiac autonomic imbalance and inflammation occur early in diabetes and are interrelated. Conclusions. Cardiac autonomic imbalance correlates with the adipose tissue-derived inflammation seen early in type 2 diabetes.
TL;DR: Spectral analysis of the HRV signal and of the respiration signal indicated a higher respiration regularity during deep sleep, and a higher parasympathetic drive was confirmed by an increase in the coherence between theHRV and the resppiration signal in the HF band during NREM sleep.
Abstract: Sleep is a complex state characterized by important changes in the autonomic modulation of the cardiovascular activity. Heart rate variability (HRV) greatly changes during different sleep stages, showing a predominant parasympathetic drive to the heart during non-rapid eye movement sleep (NREM) and an increased sympathetic activity during rapid eye movement sleep (REM). Respiration undergoes important modifications as well, becoming deeper and more regular with deep sleep and shallower and more frequent during REM. The aim of the present study is to assess both autonomic cardiac regulation and cardiopulmonary coupling variations during different sleep stages in healthy subjects, using spectral and cross-spectral analysis of the HRV and respiration signals. Polysomnographic sleep recordings were performed in 11 healthy women and the HRV signal and the respiration signal were obtained. The spectral and cross-spectral parameters of the HRV signal and of the respiration signal were computed at low frequency (LF) and at breathing frequency (high frequency, HF) during different sleep stages. Results attested a sympatho-vagal balance shift towards parasympathetic modulation during NREM sleep and towards sympathetic modulation during REM sleep. Spectral analysis of the HRV signal and of the respiration signal indicated a higher respiration regularity during deep sleep, and a higher parasympathetic drive is also confirmed by an increase in the coherence between the HRV and the respiration signal in the HF band during NREM sleep. Our findings about sleep stage-dependent variations in the HRV signal and in the respiratory activity are in line with previous evidences and confirm spectral analysis of the HRV and the respiration signal to be a suitable tool for investigating cardiac autonomic modulation and respiration activity during sleep.
TL;DR: The increased heart rate and decreased heart rate variability in CRPS suggest a general autonomic imbalance, which is an independent predictor for increased mortality and sudden death.
Abstract: Background: Complex regional pain syndrome (CRPS) is a painconditionwithregionalsensoryandautonomicabnormalities in the affected limb. The authors studied systemic autonomic and hemodynamic function in CRPS patients during rest, and during orthostatic and mental arithmetic stress. Methods: Twenty patients with CRPS and 20 age-, sex-, and body mass index-matched control subjects participated. Meanvaluesofheartratevariability,baroreceptorsensitivity, blood pressure, stroke volume, cardiac output, and total peripheral resistance were estimated during supine rest and 60° tilt-table testing. On a separate day, heart rate variability was also measured during mental arithmetic stress testing induced by a paced auditory serial addition task. Results: Heart rate was increased and heart rate variability reduced in patients with CRPS patients compared with control subjects during rest and mental and orthostatic stress, whereas baroreceptor sensitivity was unaffected. When tilted from supine to upright position, patients with CRPS were not able to preserve cardiac output in comparison with control subjects, and they exhibited an exaggerated increase in the total peripheral resistance. The hemodynamic changes correlated to pain duration but not to pain intensity. Conclusion: The increased heart rate and decreased heart rate variability in CRPS suggest a general autonomic imbalance, which is an independent predictor for increased mortality and sudden death. The inability of the patients to protect their cardiac output during orthostatic stress was aggravated with the chronicity of the disease.
TL;DR: Physiological and biochemical evaluations of human mental workloads mainly refer to the cerebral cortex, including electroencephalograms (EEGs) and event‐related potentials (ERPs).
Abstract: This paper gives a brief review and short summary on physiological and biochemical evaluations of human mental workloads. Physiological evaluations consist of peripheral physiological evaluations and central physiological evaluations. Peripheral physiological evaluations mainly include heart rate and heart rate variability (HRV) recorded from electrocardiograms (ECGs), blood pressure, respiration, eye blinks, skin potential, and hemodynamic indices. Central physiological evaluations mainly refer to the cerebral cortex, including electroencephalograms (EEGs) and event-related potentials (ERPs). Biochemical evaluations mainly include catecholamines, cortisol, and immunoglobulin A (IgA) collected from blood, salivary, or urinary samples. They are all objective measurements to evaluate mental workloads when particular mental tasks are performed. © 2011 Wiley Periodicals, Inc. © 2012 Wiley Periodicals, Inc.
TL;DR: In this paper HRV linear and nonlinear indexes are reviewed and data from real patients are provided to show how these indexes might be used in clinical practice.
Abstract: Biological organisms have intrinsic control systems that act in response to internal and external stimuli maintaining homeostasis. Human heart rate is not regular and varies in time and such variability, also known as heart rate variability (HRV), is not random. HRV depends upon organism's physiologic and/or pathologic state. Physicians are always interested in predicting patient's risk of developing major and life-threatening complications. Understanding biological signals behavior helps to characterize patient's state and might represent a step toward a better care. The main advantage of signals such as HRV indexes is that it can be calculated in real time in noninvasive manner, while all current biomarkers used in clinical practice are discrete and imply blood sample analysis. In this paper HRV linear and nonlinear indexes are reviewed and data from real patients are provided to show how these indexes might be used in clinical practice.
TL;DR: Stress induced in the evening had a significantly stronger impact on absolute and baseline corrected physiological measures in both chronotypes, and the enhanced physiological arousal in evening-types might contribute to increased vulnerability to psychological distress.
TL;DR: In this paper, various measures of the fluctuations of the sequence of intervals between beats of the human heart, and how such fluctuations can be used to assess the presence or likelihood of cardiovascular disease were examined.
Abstract: We focus on various measures of the fluctuations of the sequence of intervals between beats of the human heart, and how such fluctuations can be used to assess the presence or likelihood of cardiovascular disease. We examine sixteen such measures and their suitability for correctly classifying heartbeat records of various lengths as normal or revealing the presence of cardiac dysfunction, particularly congestive heart failure. Using receiver-operating-characteristic analysis we demonstrate that scale-dependent measures prove substantially superior to scale-independent ones. The wavelet-transform standard deviation at a scale near 32 heartbeat intervals, and its spectral counterpart near 1/32 cycles/interval, turn out to provide reliable results using heartbeat records just minutes long. We further establish for all subjects that the human heartbeat has an underlying stochastic origin rather than arising from a chaotic attractor. Finally, we develop a mathematical point process that emulates the human heartbeat time series for both normal subjects and heart-failure patients.
TL;DR: Evidence is provided that CR has direct systemic effects that counter the expected age‐associated changes in autonomic function so that HRV indexes in CR individuals are similar to those of individuals 20 years younger eating WDs.
Abstract: Caloric restriction (CR) retards aging in laboratory rodents. No information is available on the effects of long-term CR on physiologic markers of aging and longevity in humans. Heart rate variability (HRV) is a marker for cardiac autonomic functioning. The progressive decline in HRV with aging and the association of higher HRV with better health outcomes are well established. Heart rate variability assessment is a reliable tool by which the effects of CR on autonomic function can be assessed. Time- and frequency-domain analyses compared 24-h HRV in 22 CR individuals aged 35-82 years and 20 age-matched controls eating Western diets (WD). The CR group was significantly leaner than the WD group. Heart rate was significantly lower, and virtually, all HRV values were significantly higher in the CR group than in the WD group (P < 0.002). Heart rate variability in the CR individuals was comparable with published norms for healthy individuals 20 years younger. In addition, when differences in heart rate (HR) and HRV between CR and WD were compared with previously published changes in HRV induced in healthy adults given atenolol, percent differences in each measure were generally similar in direction and magnitude and suggested declines in sympathetic and increases in parasympathetic modulation of HR and increased circadian variability associated with CR. These findings provide evidence that CR has direct systemic effects that counter the expected age-associated changes in autonomic function so that HRV indexes in CR individuals are similar to those of individuals 20 years younger eating WDs.