Associations between heart rate asymmetry expression and asymmetric detrended fluctuation analysis results

Abstract

The relation between recently established asymmetry in Asymmetric Detrended Fluctuation Analysis (ADFA) and Heart Rate Asymmetry is studied. It is found that the ADFA asymmetric exponents are related both to the overall variability and to its asymmetric components at all studied time scales. We find that the asymmetry in scaling exponents, i.e., [Formula: see text] is associated with both variance-based and runs-based types of asymmetry. This observation suggests that the physiological mechanisms of both types are similar, even though their origins and mathematical methods are very different. The graphical abstract demonstrates strong, nonlinear association between the expression of Heart Rate Asymmetry measured using relative descriptors and the Asymmetric Detrended Fluctuation Analysis results. It is clear that there is a strong relation between the two theoretically disparate approaches to signal analysis. The technique to demonstrate the association is loess fit.

Keywords: ADFA; Asymmetry; HRA; HRV; RR intervals.

Fig. 1

An example of the partitioning of an $\mathit{RR}$ intervals time series into monotonic runs. The runs are marked as DRn (Deceleration Run of length n) and ARn (Acceleration run of length n); the Nn symbols stand for neutral runs which may break the deceleration/acceleration runs. Full black circles denote beginnings of decelerations runs and full gray circles mark the beginnings of accelerations runs — these can be thought of as reference points for the respective runs

Fig. 2

Distributions of monotonic runs along with the comparisons with the paired Wilcoxon test