title: On the nature of heart rate variability in a breathing normal subject: a stochastic process analysis.
abstract: Human heart rate is moderated by the autonomous nervous system acting predominantly through the sinus node (the main cardiac physiological pacemaker). One of the dominant factors that determine the heart rate in physiological conditions is its coupling with the respiratory rhythm. Using the language of stochastic processes, we analyzed both rhythms simultaneously taking the data from polysomnographic recordings of two healthy individuals. Each rhythm was treated as a sum of a deterministic drift term and a diffusion term (Kramers-Moyal expansion). We found that normal heart rate variability may be considered as the result of a bidirectional coupling of two nonlinear oscillators: the heart itself and the respiratory system. On average, the diffusion (noise) component measured is comparable in magnitude to the oscillatory (deterministic) term for both signals investigated. The application of the Kramers-Moyal expansion may be useful for medical diagnostics providing information on the relation between respiration and heart rate variability. This interaction is mediated by the autonomous nervous system, including the baroreflex, and results in a commonly observed phenomenon--respiratory sinus arrhythmia which is typical for normal subjects and often impaired by pathology.
authors: Physics of Complex Systems Division, Faculty of Physics, Warsaw University of Technology, ul Koszykowa 75, 00-662 Warsaw, Poland. buchner@if.pw.edu.pl
authors: Teodor
authors: T
authors: Buchner
authors: Monika
authors: M
authors: Petelczyc
authors: Jan J
authors: JJ
authors: Zebrowski
authors: Aleksander
authors: A
authors: Prejbisz
authors: Marek
authors: M
authors: Kabat
authors: Andrzej
authors: A
authors: Januszewicz
authors: Anna Justyna
authors: AJ
authors: Piotrowska
authors: Waldemar
authors: W
authors: Szelenberger
mesh_terms: D001341:Autonomic Nervous System / Q000502:physiology; D017704:Baroreflex / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008390:Markov Chains; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D017286:Polysomnography; D012016:Reference Values; D015656:Respiratory Mechanics / Q000502:physiology; D013269:Stochastic Processes