Complexity analyses show two distinct types of nonlinear dynamics in short heart period variability recordings.

Alberto Porta,Peter Van Leeuwen,Beatrice De Maria,Andrea Marchi,Tomaso Gnecchi-Ruscone,Aparecida M Catai,Dirk Cysarz,Vlasta Bari,Anielle C M Takahashi

doi:10.3389/fphys.2015.00071

Abstract

Two diverse complexity metrics quantifying time irreversibility and local prediction, in connection with a surrogate data approach, were utilized to detect nonlinear dynamics in short heart period (HP) variability series recorded in fetuses, as a function of the gestational period, and in healthy humans, as a function of the magnitude of the orthostatic challenge. The metrics indicated the presence of two distinct types of nonlinear HP dynamics characterized by diverse ranges of time scales. These findings stress the need to render more specific the analysis of nonlinear components of HP dynamics by accounting for different temporal scales.

Highlights

The beat-to-beat changes of heart period (HP) about its mean value, usually referred to as HP variability, were originally described as a linear superposition of rhythms (Akselrod et al, 1981)
Other studies found that the incidence of nonlinear dynamics are not affected by the magnitude of the orthostatic challenge being relevant at rest, suggesting that nonlinear components of HP variability might be present even in connection with a small respiratory sinus arrhythmia (Porta et al, 2008)
Comparison between Different Complexity Metrics for the Detection of Nonlinear Components in Short HP Variability Recordings When time irreversibility and local prediction analyses were applied to short HP variability series recorded in fetuses as a function of the week of gestation (WoG) and during graded orthostatic challenge as a function of the tilt table inclination, opposite conclusions can be drawn

Summary

Introduction

The beat-to-beat changes of heart period (HP) about its mean value, usually referred to as HP variability, were originally described as a linear superposition of rhythms (Akselrod et al, 1981). Other studies found that the incidence of nonlinear dynamics are not affected by the magnitude of the orthostatic challenge being relevant at rest, suggesting that nonlinear components of HP variability might be present even in connection with a small respiratory sinus arrhythmia (Porta et al, 2008). This apparent paradox dominates the field of the analysis of short HP variability series and deserves investigation

Methods

Results

Conclusion