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Autonomic Balance (autonomic + balance)
Selected AbstractsAutonomic Function during Closed Loop Stimulation and Fixed Rate Pacing: Heart Rate Variability Analysis from 24-Hour Holter RecordingsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2010RAFFAELE QUAGLIONE M.D. Aim: Aim of this retrospective study was to analyze the effect of closed-loop stimulation (CLS) and DDD pacing mode on autonomic balance, and to evaluate heart rate variability (HRV) during CLS stimulation. Methods and Materials: Autonomic balance was estimated by a 24-hour HRV analysis of paced and spontaneous beats in patients implanted with a dual-chamber pacemaker (Inos2+ CLS,Biotronik GmbH, Berlin, Germany) and randomly assigned to CLS or DDD pacing mode. Patients underwent two 24-hour electrocardiogram Holter recordings at the end of each 3-month pacing mode period. Each Holter recording was automatically scanned to extract sequences of consecutive beats of the same type [atrial paced (Ap)-sequence and atrial spontaneous (As)-sequence], lasting at least 130 beats. Results: Eight hundred and ten sequences were extracted from 15 patients, and the following spectral parameters were evaluated during both CLS and DDD mode: the total power (variance), the absolute and percentage (relative to the total power) powers of the low frequency (LF, 0.04,0.15 Hz) and high frequency (HF, 0.15,0.4 Hz) components, as well as the LF/HF power ratio. Discussion: The two main findings of this study were: in all the patients, CLS seems to mimic short-term physiological HRV, although the variability (total power) was lower than that relative to the spontaneous beats; the HRV of the spontaneous beats had an higher LF/HF when the pacemaker was programmed as DDD respect to CLS, consistent with a shift toward sympathetic predominance. PACE 2010; 33:337,342) [source] An evaluation of a visual biofeedback intervention in dyslexic adultsDYSLEXIA, Issue 1 2005Elizabeth Liddle Abstract A prototype of a biofeedback system designed to treat dyslexia by improving heart-rate variability was evaluated in a single blind study of dyslexic adults. Treatment consisted of four 15 minute exposures to a visual display synchronized with either the participant's own cardiac cycle (intervention condition), or of a synthesized cardiac cycle (placebo condition). Repeated measures were made of picture naming speed, single word reading speed and accuracy, copying speed, heart-rate variability and performance on a lateralized visual temporal order judgement task. Small but significant improvements were found in reading and naming speed in the treatment group relative to the placebo group. No significant improvements were found in unspeeded reading measures. Results from heart-rate measures indicated that treatment had effected a shift in the ratio between parameters reflecting the influence of the sympathetic and parasympathetic autonomic nervous systems (ANS), respectively, in favour of the parasympathetic. In the temporal order judgement task, participants who received treatment showed a reduced level of overall improvement relative to that seen in those who received placebo, coupled with evidence of a shift in visual attention from left to right hemifield in their pattern of performance. The results are interpreted as indicating that the treatment induces a shift in autonomic balance in favour of the parasympathetic ANS, and that this shift is also reflected in increased efficiency of left cerebral hemisphere circuits implicated in the perceptual-motor processes required for naming and reading fluency. Conversely, it is also reflected in lower spatial awareness of peripheral visual stimuli, particularly those presented to left hemifield. Copyright © 2004 John Wiley & Sons, Ltd. [source] Heart rate variability in beta-thalassemia patientsEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2009Wasarut Rutjanaprom Abstract Background:, Cardiac failure remains the major cause of death in beta-thalassemia major (TM). Reduced heart rate variability (HRV) is associated with a higher risk of arrhythmias after myocardial infarction and heart failure. We evaluated HRV in TM patients and its relationship with hemodynamics and echocardiographic parameters during a 6-month follow-up. Methods:, Thirty-four TM patients (19 ± 10 yr) and 20 healthy subjects (17 ± 6 yr) were evaluated. Hematologic, biochemical, echocardiographic and HRV parameters were determined at entry and at 6-month follow-up. Time and frequency domain HRV parameters were analyzed from 24-h recorded electrocardiograms. All TM patients received blood transfusion and chelation therapy. Results:, Both time and frequency domain HRV parameters were markedly reduced in TM patients, compared to the control. The significantly improved HRV was seen in correlation with higher hemoglobin (Hb) level when compared within TM group at different time point. No correlation was seen between HRV and serum ferritin, reactive oxygen species (ROS) and non-transferrin bound iron (NTBI). Conclusion:, HRV is depressed in TM patients. HRV was significantly correlated with Hb level, suggesting that anemia greatly influences the cardiac autonomic balance. [source] Body Position and Cardiac Dynamic and Chronotropic Responses to Steady-State Isocapnic Hypoxaemia in HumansEXPERIMENTAL PHYSIOLOGY, Issue 2 2000S. Deborah Lucy Neural mediation of the human cardiac response to isocapnic (IC) steady-state hypoxaemia was investigated using coarse-graining spectral analysis of heart rate variability (HRV). Six young adults were exposed in random order to a hypoxia or control protocol, in supine and sitting postures, while end-tidal PCO2 (PET,CO2) was clamped at resting eucapnic levels. An initial 11 min period of euoxia (PET,O2 100 mmHg; 13.3 kPa) was followed by a 22 min exposure to hypoxia (PET,O2 55 mmHg; 7.3 kPa), or continued euoxia (control). Harmonic and fractal powers of HRV were determined for the terminal 400 heart beats in each time period. Ventilation was stimulated (P < 0.05) and cardiac dynamics altered only by exposure to hypoxia. The cardiac interpulse interval was shortened (P < 0.001) similarly during hypoxia in both body positions. Vagally mediated high-frequency harmonic power (Ph) of HRV was decreased by hypoxia only in the supine position, while the fractal dimension, also linked to cardiac vagal control, was decreased in the sitting position (P < 0.05). However, low-frequency harmonic power (Pl) and the HRV indicator of sympathetic activity (Pl/Ph) were not altered by hypoxia in either position. These results suggest that, in humans, tachycardia induced by moderate IC hypoxaemia (arterial O2 saturation Sa,O2, 85%) was mediated by vagal withdrawal, irrespective of body position and resting autonomic balance, while associated changes in HRV were positionally dependent. [source] Heart Rate Variability and Sympathetic Skin Response in Male Patients Suffering From Acute Alcohol Withdrawal SyndromeALCOHOLISM, Issue 9 2006Karl-Jürgen Bär Background: Many symptoms of alcohol withdrawal (AW) such as tachycardia or elevated blood pressure might be explained by increased peripheral and central adrenergic activity. In contrast to many neurochemical studies of sympathetic activation during AW, only very few studies investigated autonomic balance using neurophysiological methods. Methods: We investigated heart rate variability (HRV) and sympathetic skin response (SSR) in male patients suffering from mild AW syndrome (n=20, no treatment required) and in patients with moderate to severe AW syndrome (n=20, clomethiazole treatment) in the acute stage. Sympathovagal influence was quantified using measures of time and frequency domain of HRV as well as modern nonlinear parameters (compression entropy). Furthermore, we obtained latencies and amplitudes of SSR to quantify isolated sympathetic influence. Measures were obtained during the climax of withdrawal symptomatology before treatment, 1 day after climax, and shortly before discharge from hospital. Alcohol withdrawal scores were obtained and correlated to autonomic measures. Results: Ambulatory blood pressure and AW scores revealed characteristic withdrawal symptoms in both patient groups. Apart from the nonlinear parameter compression entropy, Hc, measures of HRV revealed no sign of autonomic dysfunction in contrast to the significantly increased heart rates at the time of admission. Latencies and amplitudes of SSR did not indicate any increase of sympathetic activity. A negative correlation was found between Hc and mental withdrawal symptoms. Conclusions: We show here that classical measures for autonomic nervous system activity such as HRV and SSR are not suitable for describing the autonomic changes seen in acute AW, although a major role for the sympathetic nervous system has been proposed. This might be due to multiple dysregulation of metabolites in AWS or to subtle alcohol-induced damage to neuronal structures, issues that should be addressed in future studies. [source] Autonomic Function during Closed Loop Stimulation and Fixed Rate Pacing: Heart Rate Variability Analysis from 24-Hour Holter RecordingsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2010RAFFAELE QUAGLIONE M.D. Aim: Aim of this retrospective study was to analyze the effect of closed-loop stimulation (CLS) and DDD pacing mode on autonomic balance, and to evaluate heart rate variability (HRV) during CLS stimulation. Methods and Materials: Autonomic balance was estimated by a 24-hour HRV analysis of paced and spontaneous beats in patients implanted with a dual-chamber pacemaker (Inos2+ CLS,Biotronik GmbH, Berlin, Germany) and randomly assigned to CLS or DDD pacing mode. Patients underwent two 24-hour electrocardiogram Holter recordings at the end of each 3-month pacing mode period. Each Holter recording was automatically scanned to extract sequences of consecutive beats of the same type [atrial paced (Ap)-sequence and atrial spontaneous (As)-sequence], lasting at least 130 beats. Results: Eight hundred and ten sequences were extracted from 15 patients, and the following spectral parameters were evaluated during both CLS and DDD mode: the total power (variance), the absolute and percentage (relative to the total power) powers of the low frequency (LF, 0.04,0.15 Hz) and high frequency (HF, 0.15,0.4 Hz) components, as well as the LF/HF power ratio. Discussion: The two main findings of this study were: in all the patients, CLS seems to mimic short-term physiological HRV, although the variability (total power) was lower than that relative to the spontaneous beats; the HRV of the spontaneous beats had an higher LF/HF when the pacemaker was programmed as DDD respect to CLS, consistent with a shift toward sympathetic predominance. PACE 2010; 33:337,342) [source] Influence of Age on Linear and Nonlinear Measures of Autonomic Cardiovascular ModulationANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010Michael K. Boettger M.D. Background: Age has been identified as an independent risk factor for cardiovascular diseases. In addition, autonomic imbalance toward sympathetic preponderance has been shown to facilitate the occurrence of heart disease. Here, we aimed to assess autonomic modulation of cardiovascular parameters during normal ageing applying well-established linear and novel nonlinear parameters. Methods: Linear and nonlinear measures of heart rate variability and complexity as well as measures of QT interval variability and baroreflex sensitivity were obtained from a total of 131 healthy, medication-free participants from a continuous age range between 20 and 90 years, who were allocated to three different age groups. Results: Heart rate variability and complexity significantly decreased with age, while regularity of heart rate time series increased. In addition, QT interval variability linearly increased with age, while baroreflex sensitivity showed a pronounced decrease. Overall, concerning effects of ageing, linear and nonlinear parameters showed equal differentiation between groups. Conclusion: These data indicate a shift of autonomic balance toward sympathetic predominance in higher age groups, limiting the reactiveness of the cardiovascular system to adjust to different demands and increasing the risk for developing tachyarrhythmias. Ann Noninvasive Electrocardiol 2010;15(2):165,174 [source] Playing a violent television game affects heart rate variabilityACTA PAEDIATRICA, Issue 1 2009Malena Ivarsson Abstract Objective: To investigate how playing a violent/nonviolent television game during the evening affects sympathetic and parasympathetic reactions during and after playing as well as sleep quality during the night after playing. Subjects and Methods: In total, 19 boys, 12,15 years of age, played television games on two occasions in their homes and participated once without gaming. Heart rate, heart rate variability (HRV) and physical activity were measured during gaming/participating and the night to follow using a portable combined heart rate and movement sensor. A sleep diary and questionnaires about gaming experiences and session-specific experiences were filled in. Criteria for Selection of Games: Violent game involves/rewards direct physical violence (no handguns) against another person, and nonviolent game involves/rewards no violence; same game design (,third-person game'); conducted in the same manner; no differences concerning motor activity; similar sound and light effects; no sexual content, violence against women or racial overtones. Results: During violent (vs. nonviolent) gaming, there was significantly higher activity of the very low frequency component of the HRV and total power. During the night after playing, very low frequency, low frequency and high frequency components were significantly higher during the violent (vs. nonviolent) condition, just as total power. There were no significant differences between the three conditions (violent/nonviolent/no gaming) with respect to an index reflecting subjectively perceived sleep difficulties. Nor was there any difference between violent and nonviolent condition for any single sleep item. Conclusion: Violent gaming induces different autonomic responses in boys compared to nonviolent gaming , during playing and during the following night , suggesting different emotional responses. Subjectively perceived sleep quality is not influenced after a single gaming experience. Future studies should address the development of the autonomic balance after gaming over longer time than a night, physiological adaptation to frequent gaming and potential gender differences. [source] Altered cardiovascular vagal responses in nonelderly female patients with subclinical hyperthyroidism and no apparent cardiovascular diseaseCLINICAL ENDOCRINOLOGY, Issue 2 2007Renata Boschi Portella Summary Objective Subclinical hyperthyroidism (SH) has been associated with exercise intolerance, changes in cardiac morphology, atrial arrhythmias and sympathovagal imbalance. The aim of this study was to evaluate the vagal reserve and modulation by a sympathetic stimulus in nonelderly patients with SH without cardiovascular problems. Design We carried out a cross-sectional study, comparing data of the heart rate variability (HRV) of SH patients and healthy controls at rest and after vagal and sympathetic stimulation. Patients We studied 16 female patients with at least 6 months of SH and 16 healthy female controls with the same median age (40 vs. 34·5 years). Measurements We used the tilt test, with electrocardiographic record at rest, during the respiratory sinus arrhythmia (RSA) manoeuvre and after tilting, in order to analyse HRV in the frequency domain (%high frequency (HF) and low/high frequency ratio (LF/HF) using Biopotentials Captation System software. Results The median TSH level was 0·03 mU/l in patients and 1·37 mUI/l in controls. The median free T4 was 1·37 ng/dl in patients and 1·20 ng/dl in controls. Patients demonstrated a significantly smaller difference between %HF during the RSA and %HF at rest than controls (median ,7·5 vs. 36·6, P < 0·001). There was a lower difference between LF/HF ratio after tilting and LF/HF ratio at rest in patients than in controls (1·5 vs. 5·3, P = 0·005). Conclusion Subclinical hyperthyroidism affects cardiovascular autonomic balance in otherwise apparently healthy nonelderly females by blunting vagal responses. [source] | ||||||||||