Multifractal analysis of normal RR heart-interbeat signals in power spectra ranges

TL;DR

This study applies multifractal analysis techniques to normal heart rate signals, revealing distinct spectral properties during day and night, and providing insights into physiological heart rate variability.

Contribution

It introduces the use of Wavelet Transform Modulus Maxima and Multifractal Detrended Fluctuation Analysis to analyze multifractal properties of heart rate spectra in different frequency ranges.

Findings

Presence of stochastic persistence in LF range

Loss of variability during night in VLF range

Increase in variability in ULF range at night

Abstract

Power spectral density is an accepted measure of heart rate variability. Two estimators of multifractal properties: Wavelet Transform Modulus Maxima and Multifractal Detrended Fluctuation Analysis are used to investigate multifractal properties for the three strongly physiologically grounded components of power spectra: low frequency (LF), very low frequency (VLF) and ultra low frequency (ULV). Circadian rhythm changes are examined by discrimination of daily activity from nocturnal rest. Investigations consider normal sinus rhythms of healthy 39 subjects which are grouped in two sets: 5-hour wake series and 5-hour sleep series. Qualitative arguments are provided to conjecture the presence of stochastic persistence in LF range, loss of heart rate variability during night in VLF range and its increase in ULF.