Analysis of correlations in heart dynamics in wake and sleep phases

Abstract

We study correlations in time series of RR intervals of subjects with normal sinus rhythm (NSR) during sleep and wake phases and we also analyze time series of subjects with congestive heart failure (CHF) in both phases. We use detrended fluctuation analysis (DFA), the Higuchi's method and multifractal analysis. We have obtained different results for sleep and wake phases. The time series of healthy subjects show long-range correlations during sleep and wake conditions; on the other hand, for CHF subjects we have found different correlations during sleep and wake phases. This is confirmed by using both DFA and Higuchi's methods. We have found that the width of the multifractal spectra is practically the same for both phases of healthy subjects and CHF subjects. However, when we study with detail the spectra we observe that the spectra of unhealthy persons are almost symmetrical whereas the spectra of healthy subjects are asymmetrical.

Laser speckle contrast imaging: Multifractal analysis of data recorded in healthy subjects

“…28 and 29) and can be useful for diagnoses purposes (see, e.g., Refs. [30][31][32]. Multifractal analyses of LSCI data could therefore provide information for clinicians.…”

Classification of Prolapsed Mitral Valve versus Healthy Heart from Phonocardiograms by Multifractal Analysis

“…Multifractal behaviour of the cardiovascular system is investigated through analysis of Hölder exponents and fractal behavior using different approaches, such as detrended fluctuation analysis (DFA) and self-affine fractal variability analysis of heartbeat dynamics [17, 18], local variability analysis [19, 20], analysis of healthy and pathological dynamics from the aspect of respiratory rate variability [21] and brain activity in healthy patients [21, 22], analysis of Hölder exponents using laser Doppler flowmetry technique [23], analysis of progressive central hypovolemia influence [24, 25], estimation of heart rate variability (HRV) large deviations [26], and arrhythmia [27]. Many variations of cardiosignals are examined using multifractality, age-related changes [28, 29], as well as changes in heart dynamics: before and after particular treatment [30], for different human races [31], body positions [23], and during wake and sleep phases [32, 33]. Heartbeat dynamics is compared between a group of healthy patients and a group of patients with heart failures [17].…”