title: Propagating unstable wavelets in cardiac tissue.
abstract: Solitonlike propagating modes have been proposed for excitable tissue, but have never been measured in cardiac tissue. In this study, we simulate an experimental protocol to elicit these propagating unstable wavelets (PUWs) in a detailed three-dimensional ventricular wedge preparation. PUWs appear as fixed-shape wavelets that propagate only in the direction of cardiac fibers, with conduction velocity approximately 40% slower than normal action potential excitation. We investigate their properties, demonstrating that PUWs are not true solitons. The range of stimuli for which PUWs were elicited was very narrow (several orders of magnitude lower than the stimulus strength itself), but increased with reduced sodium conductance and reduced coupling in nonlongitudinal directions. We show that the phenomenon does not depend on the particular membrane representation used or the shape of the stimulating electrode.
authors.affiliation: Institute for Computational Medicine, Johns Hopkins University, 3400 North Charles Avenue, Baltimore, Maryland 21218, USA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Boyle
authors.forename: Adarsh
authors.initials: A
authors.lastname: Madhavan
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Reid
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Vigmond
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D003198:Computer Simulation; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular