Home About us Contact
|
Home About us Contact | ||
|
|
||
HRV Indices (hrv + index)
Selected AbstractsImpact of body fat mass extent on cardiac autonomic alterations in womenEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 8 2009J. Sztajzel Abstract Background, Obesity has been associated with significant abnormalities of the cardiac autonomic regulation. However, the precise impact of increasing body weight on cardiac autonomic function and the metabolic and hormonal contributors to these changes are presently unclear. The aim of our study was to explore in subjects with increasing values of body mass index (BMI) the alterations of cardiac autonomic function and to establish the potential role of various metabolic and hormonal contributors to these alterations. Materials and methods, We investigated time and frequency domain heart rate variability (HRV) parameters taken from 24-h Holter recordings, and several anthropometric, metabolic and hormonal parameters (plasma glucose, insulin, triglycerides, free fatty acids, leptin and adiponectin) in 68 normoglycaemic and normotensive women (mean age of 40 ± 3 years), subdivided according to their BMI into 15 normal body weight (controls), 15 overweight, 18 obese and 20 morbidly obese. Results, Heart rate was increased and HRV was decreased in the morbidly obese group as compared with controls. In overall population, a negative association linked body fat mass (FM) to HRV indices. None of the metabolic and hormonal parameters were significantly related to the HRV indices, after they were adjusted for the body FM. Conclusions, Morbidly obese, normoglycaemic and normotensive young women have increased HR and low HRV, indicating an abnormal cardiac autonomic function and representing a risk factor for adverse cardiovascular events. A decrease of HRV parameters is associated with a progressive increase of body FM. Other metabolic and hormonal factors, characterising obesity, do not show an independent influence on these HRV alterations. [source] Effect of intensive training on heart rate variability in prepubertal swimmersEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2005A. Vinet Abstract Background, In children, there is very limited evidence focusing on the beneficial effect of exercise training on heart rate variability (HRV) during childhood. Despite the fact that more and more children are engaged in intensive training programs, the question arises if such intensive training involves deleterious effects on the cardiac autonomic nervous system during childhood. Thus the aim of the present study was to compare HRV parameters in highly trained swimmer boys and untrained counterparts. Methods, Twenty prepubertal boys, aged 11,12 years old, took part in the study. The children were divided into 11 highly trained prepubertal swimmers (training sessions of 8,10 h weekly for at least 4 years) and 9 age-matched active boys. HRV analysis was performed on diurnal recordings in the frequency (short-term recordings 6 min the most ,vagal') and time (long-term recordings 4 h centred on the 6 min most ,vagal') domains. Results, No significant differences were obtained between groups for all frequency variables whatever the mode of expression (absolute in ms2, relative in Ln or %). All time-domain components were not significantly different in swimmers and untrained boys. Conclusions, The results of the present study demonstrate that participating intensively in swimming training does not induce in children changes in HRV indices. Neither time nor domain HRV variables were significantly different between untrained and highly trained prepubertal boys. Thus, intensive training in healthy children does not involve deleterious effects on HRV. [source] Nonlinear Indices of Heart Rate Variability in Chronic Heart Failure Patients: Redundancy and Comparative Clinical ValueJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2007ROBERTO MAESTRI M.S. Aims: We aimed to assess the mutual interrelationships and to compare the prognostic value of a comprehensive set of nonlinear indices of heart rate variability (HRV) in a population of chronic heart failure (CHF) patients. Methods and Results: Twenty nonlinear HRV indices, representative of symbolic dynamics, entropy, fractality-multifractality, predictability, empirical mode decomposition, and Poincaré plot families, were computed from 24-hour Holter recordings in 200 stable CHF patients in sinus rhythm (median age [interquartile range]: 54 [47,58] years, LVEF: 23 [19,28]%, NYHA class II,III: 88%). End point for survival analysis (Cox model) was cardiac death or urgent transplantation. Homogeneous variables were grouped by cluster analysis, and in each cluster redundant variables were discarded. A prognostic model including only known clinical and functional risk factors was built and the ability of each selected HRV variable to add prognostic information to this model assessed. Bootstrap resampling was used to test the models stability. Four nonlinear variables showed a correlation >0.90 with classical linear ones and were discarded. Correlations >0.80 were found between several nonlinear variables. Twelve clusters were obtained and from each cluster a candidate predictor was selected. Only two variables (from empirical mode decomposition and symbolic dynamics families) added prognostic information to the clinical model. Conclusion: This exploratory study provides evidence that, despite some redundancies in the informative content of nonlinear indices and strong differences in their prognostic power, quantification of nonlinear properties of HRV provides independent information in risk stratification of CHF patients. [source] Sometimes Higher Heart Rate Variability Is Not Better Heart Rate Variability: Results of Graphical and Nonlinear AnalysesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2005PHYLLIS K. STEIN Ph.D. Objective: To determine the prevalence and effect on traditional heart rate variability (HRV) indices of abnormal HRV patterns in the elderly. Methods: Hourly Poincaré plots and plots of spectral HRV from normal-to-normal interbeat intervals and hourly nonlinear HRV values were examined in a subset of 290 consecutive participants in the Cardiovascular Health Study. Only subjects in normal sinus rhythm with ,18 hours of usable data were included. Eligible subjects were 71 ± 5 years. During 7 years of follow-up, 21.7% had died. Hours were scored as normal (0), borderline (0.5), or abnormal (1) from a combination of plot appearance and HRV. Summed scores were normalized to 100% to create an abnormality score (ABN). Short-term HRV versus each 5th percentile of ABN was plotted and a cutpoint for markedly increased HRV identified. The t -tests compared HRV for subjects above and below this cutpoint. Cox regression evaluated the association of ABN and mortality. Results: Of 5,815 eligible hourly plots, 64.4% were normal, 14.5% borderline, and 21.1% abnormal. HR, SDNN, SDNNIDX, ln VLF and LF power, and power law slope did not differ by the cutpoint for increased short-term HRV, while SDANN and ln ULF power were significantly lower for those above the cutpoint. However, many HRV indices including LF/HF ratio and normalized LF and HF power were significantly different between groups (P < 0.001). Increased ABN was significantly associated with mortality (P = 0.019). Despite similar values for many HRV indices, being in the group above the cutpoint was significantly associated with mortality (P = 0.04). Conclusions: Abnormal HR patterns that elevate many HRV indices are prevalent among the elderly and associated with higher risk of mortality. Consideration of abnormal HRV may improve HRV-based risk stratification. [source] Interleukin-6 Levels are Inversely Correlated with Heart Rate Variability in Patients with Decompensated Heart FailureJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2001DORON ARONSON M.D. Interleukin-6 and Heart Rate Variability.Introduction: Increased local and systemic elaboration of cytokines have an important role in the pathogenesis of congestive heart failure (CHF) through diverse mechanisms. Because cytokines are known to act at the neuronal level in both the peripheral and central nervous system, we sought to determine whether increased cytokine levels are associated with the autonomic dysfunction that characterizes CHF. Methods and Results: We studied 64 patients admitted for decompensated CHF (mean age 59 ± 12 years). Autonomic function was assessed using time, and frequency-domain heart rate variability (HRV) measures, obtained from 24-hour Holter recordings. In addition, norepinephrine, tumor necrosis factor-, (TNF-,), and interleukin-6 (IL-6) were measured in all patients. TNF-, levels did not correlate with any of the HRV measures. IL-6 inversely correlated with the time-domain parameters of standard deviation of RR intervals (SDNN) (r =,0.36, P = 0.004) and standard deviation of all 5,minute mean RR intervals (SDANN) (r =,0.39, P = 0.001), and with the frequency-domain parameters of total power (TP) (r =,0.37, P = 0.003) and ultralow-frequency (ULF) power (r =,0.43, P = 0.001). No correlation was found between IL-6 and indices of parasympathetic modulation. Using multiple linear regression models, adjusting for clinical variables and drug therapies, the strong inverse relationship between IL-6 and SDNN (P = 0.006), SDANN (P = 0.001), TP (P = 0.04), and ULF power (P = 0.0007) persisted. Conclusion: Reduction of long-term HRV indices is associated with increased levels of IL-6 in patients with decompensated heart failure. The ability of long-term HRV parameters to better reflect activation of diverse hormonal systems may explain their greater prognostic power for risk stratification in patients with CHF. [source] The Impact of the Components of Metabolic Syndrome on Heart Rate Variability: Using the NCEP-ATP III and IDF DefinitionsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2008KYOUNG-BOK MIN M.D., Ph.D. Background: This study examined the relationship between metabolic syndrome (MetS) and heart rate variability (HRV) in Korean adults. Methods: Data were collected from family health examinations performed from December 2003 through January 2004, and 1,041 subjects consisting of males and females aged 20,87 years were included in this study. Measurement of the 5-minute HRV and several examinations for MetS were completed. The HRV was analyzed in both the time domain with the standard deviation of NN (SDNN) intervals and the frequency domain with the low frequency (LF) and high frequency (HF) components. MetS was defined by the criteria of the National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) and the International Diabetes Federation (IDF). Results: There were significant differences in the MetS components and HRV indices between the two groups (with vs without MetS). The adjusted means of the HRV indices in the group with MetS were significantly lower than those in the group without MetS (P < 0.05). Furthermore, a significant negative correlation was found between all components of MetS and the HRV indices; additionally, as the number of MetS components increased, the HRV indices gradually decreased. Conclusions: Decreased cardiac autonomic tone was strongly associated with an increased cardiovascular risk, and HRV measurement could become an indispensable part of evaluating one's risk of cardiovascular disease, though we currently do not have sufficient information to identify the cutoff values for the HRV indices. [source] Ectopic Beats in Heart Rate Variability Analysis: Effects of Editing on Time and Frequency Domain MeasuresANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2001Mirja A. Salo M.Sc. Background: Various methods can be used to edit biological and technical artefacts in heart rate variability (HRV), but there is relatively little information on the effects of such editing methods on HRV. Methods: The effects of editing on HRV analysis were studied using R-R interval data of 10 healthy subjects and 10 patients with a previous myocardial infarction (Ml). R-R interval tachograms of verified sinus beats were analyzed from short-term (,5 min) and long-term (,24 hours) recordings by eliminating different amounts of real R-R intervals. Three editing methods were applied to these segments: (1) interpolation of degree zero, (2) interpolation of degree one, and (3) deletion without replacement. Results: In time domain analysis of short-term data, the standard deviation of normal-to-normal intervals (SDANN) was least affected by editing, and 30%-50% of the data could be edited by all the three methods without a significant error (< 5%). In the frequency domain analysis, the method of editing resulted in remarkably different changes and errors for both the high-frequency (HF) and the low-frequency (LF) spectral components. The editing methods also yielded in different results in healthy subjects and AMI patients. In 24-hour HRV analysis, up to 50% could be edited by all methods without an error larger than 5% in the analysis of the standard deviation of normal to normal intervals (SDNN). Both interpolation methods also performed well in the editing of the long-term power spectral components for 24-hour data, but with the deletion method, only 5% of the data could be edited without a significant error. Conclusions: The amount and type of editing R-R interval data have remarkably different effects on various HRV indices. There is no universal method for editing ectopic beats that could be used in both the time-domain and the frequency-domain analysis of HRV. A.N.E. 2001;6(1):5,17 [source] Heart rate variability in type 2 spinocerebellar ataxiaACTA NEUROLOGICA SCANDINAVICA, Issue 5 2010J. Montes-Brown Montes-Brown J, Sánchez-Cruz G, García AM, Báez ME, Velázquez-Pérez L. Heart rate variability in type 2 spinocerebellar ataxia. Acta Neurol Scand: 2010: 122: 329,335. © 2010 The Authors Journal compilation © 2010 Blackwell Munksgaard. Objectives,,, To explore cardiovascular autonomic regulation in Spinocerebellar ataxia type 2 (SCA2) patients, using heart rate variability (HRV) analysis and neurophysiologic autonomic reflex tests, and determine relations and causal related factors of dysautonomia in SCA2. Materials and methods,,, Heart rate variability indices for 5 min series of RR intervals were analyzed in 97 SCA2 patients, assessed quantitatively for somatic and autonomic nervous system complaints applying the International Cooperative Ataxia Rating Scale and Scales for Outcomes in Parkinson's disease (SCOPA-AUT), respectively. Autonomic testing included: resting control, standing, Valsalva maneuver and deep breathing. Results,,, Mean RR, long- and short-term variability indices and spectral density power (LF, HF) indices were lower in the patients group, whereas LF/HF ratio and LF (nu) were higher. Highly differences between groups were observed for seven diagnostic autonomic test indices. Significant correlations were found between different clinical and demographic indices and between clinical indices and some HRV indices. Conclusions,,, We confirm the presence of cardiovascular autonomic dysfunction in a large group of SCA2 patients. [source] Orthostatic heart rate variability analysis in idiopathic Parkinson's diseaseACTA NEUROLOGICA SCANDINAVICA, Issue 5 2006E. Mihci Objectives ,, We evaluated time and spectral analyses of 24-h heart rate variability (HRV) and the heart rate responses to passive tilt in patients with idiopathic Parkinson's disease (IPD) in order to investigate cardiovascular autonomic functions. Material and methods ,, Twenty-three subjects with IPD without autonomic symptoms and 15 age-matched healthy controls were enrolled. Frequency- and time-domain HRV parameters were studied during resting and passive head-up tilt (HUT) test. Results ,, All time-domain parameters were found to be low in patients with IPD. In patients with IPD, both low frequency (LF) and high frequency (HF) decreased during HUT period and no significant change in LF to HF ratio was noted. Both time- and frequency-domain HRV indices showed no correlation with age, disease severity and duration, and with l -dopa medication. Conclusion ,, The results indicate that impairment of autonomic nervous system function in IPD without autonomic symptoms is frequent, and does not show clear association with clinical stage and the age of the patients. [source] Clinical and demographic determinants of heart rate variability in patients post myocardial infarction: Insights from the cardiac arrhythmia suppression trial (CAST)CLINICAL CARDIOLOGY, Issue 3 2000Phyllis K. Stein PH.D. Abstract Background: Clinical and demographic determinants of heart rate variability (HRV), an almost universal predictor of increased mortality, have not been systematically investigated in patients post myocardial infarction (MI). Hypothesis: The study was undertaken to evaluate the relationship between pretreatment clinical and demographic variables and HRV in the Cardiac Arrhythmia Suppression Trial (CAST). Methods: CAST patients were post MI and had , 6 ventricular premature complexes/h on pretreatment recording. Patients in this substudy (n = 769) had usable pretreatment and suppression tapes and were successfully randomized on the first antiarrhythmic treatment. Tapes were rescanned; only time domain HRV was reported because many tapes lacked the calibrated timing signal needed for accurate frequency domain analysis. Independent predictors of HRV were determined by stepwise selection. Results: Coronary artery bypass graft surgery (CABG) after the qualifying MI was the strongest determinant of HRV. The markedly decreased HRV associated with CABG was not associated with increased mortality. Ejection fraction and diabetes were also independent predictors of HRV. Other predictors for some indices of HRV included beta-blocker use, gender, time from MI to Holter, history of CABG before the qualifying MI, and systolic blood pressure. Decreased HRV did not predict mortality for the entire group. For patients without CABG or diabetes, decreased standard deviation of all NN intervals (SDANN) predicted mortality. Clinical and demographic factors accounted for 31% of the variance in the average of normal-to-normal intervals (AVGNN) and 13,26% of the variance in other HRV indices. Conclusions: Heart rate variability post MI is largely independent of clinical and demographic factors. Antecedent CABG dramatically reduces HRV. Recognition of this is necessary to prevent misclassification of risk in patients post infarct. [source] | ||||||||||