title: Applications of control theory to the dynamics and propagation of cardiac action potentials.
abstract: Sudden cardiac arrest is a widespread cause of death in the industrialized world. Most cases of sudden cardiac arrest are due to ventricular fibrillation (VF), a lethal cardiac arrhythmia. Electrophysiological abnormalities such as alternans (a beat-to-beat alternation in action potential duration) and conduction block have been suspected to contribute to the onset of VF. This study focuses on the use of control-systems techniques to analyze and design methods for suppressing these precursor factors. Control-systems tools, specifically controllability analysis and Lyapunov stability methods, were applied to a two-variable Karma model of the action-potential (AP) dynamics of a single cell, to analyze the effectiveness of strategies for suppressing AP abnormalities. State-feedback-integral (SFI) control was then applied to a Purkinje fiber simulated with the Karma model, where only one stimulating electrode was used to affect the system. SFI control converted both discordant alternans and 2:1 conduction block back toward more normal patterns, over a wider range of fiber lengths and pacing intervals compared with a Pyragas-type chaos controller. The advantages conferred by using feedback from multiple locations in the fiber, and using integral (i.e., memory) terms in the controller, are discussed.
authors.affiliation: Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA. laura.m.munoz@gmail.com
authors.forename: Laura M
authors.initials: LM
authors.lastname: Muñoz
authors.forename: Jonathan F
authors.initials: JF
authors.lastname: Stockton
authors.forename: Niels F
authors.initials: NF
authors.lastname: Otani
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D054537:Atrioventricular Block / Q000503:physiopathology; D003198:Computer Simulation; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D022062:Electrophysiologic Techniques, Cardiac; D006321:Heart / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008955:Models, Cardiovascular; D011690:Purkinje Fibers / Q000503:physiopathology; D014693:Ventricular Fibrillation / Q000150:complications / Q000503:physiopathology*
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