title: Heart rate variability effect on the myocyte action potential duration restitution: insights from switched systems theory.
abstract: The physiological heart rate presents a stochastic behavior known as heart rate variability (HRV). In this framework the influence of HRV on the action potential duration (APD) of the atrial myocyte is analyzed in a computer model. We have found that introducing HRV into the myocyte action potential model decreases the APD of the extra beat S2 in an S1-S2 protocol compared to constant heart rate. A possible theoretical explanation for this is also presented and is derived from switched systems theory. It is suggested to consider the myocyte action potential phase 4 and phase 2 as two operation modes of a switching system and analyze the stability of switching between them. Since random switching is known to have a stabilization effect on a switching system, this might explain why HRV has a stabilization effect on the myocyte APD restitution. Implications of this finding include reduced system stability for conditions with low HRV. A possible application for this phenomenon regards artificial pacemakers, where a preset added HRV is predicted to reduce susceptibility to arrhythmias.
authors.affiliation: Department of Biomedical Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel. dvirhila@post.tau.ac.il
authors.forename: Hila
authors.initials: H
authors.lastname: Dvir
authors.forename: Sharon
authors.initials: S
authors.lastname: Zlochiver
mesh_terms: D016275:Atrial Function / Q000502:physiology*; D003198:Computer Simulation; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D015233:Models, Statistical; D032383:Myocytes, Cardiac / Q000502:physiology*; D013269:Stochastic Processes