Vulnerability in an excitable medium: analytical and numerical studies of initiating unidirectional propagation.

Journal Article

Cardiac tissue can display unusual responses to certain stimulation protocols. In the wake of a conditioning wave of excitation, spiral waves can be initiated by applying stimuli timed to occur during a period of vulnerability (VP). Although vulnerability is well known in cardiac and chemical media, the determinants of the VP and its boundaries have received little theoretical and analytical study. From numerical and analytical studies of reaction-diffusion equations, we have found that 1) vulnerability is an inherent property of Beeler-Reuter and FitzHugh-Nagumo models of excitable media; 2) the duration of the vulnerable window (VW) the one-dimensional analog of the VP, is sensitive to the medium properties and the size of the stimulus field; and 3) the amplitudes of the excitatory and recovery processes modulate the duration of the VW. The analytical results reveal macroscopic behavior (vulnerability) derived from the diffusion of excitation that is not observable at the level of isolated cells or single reaction units.

Full Text

Duke Authors

Cited Authors

  • Starmer, CF; Biktashev, VN; Romashko, DN; Stepanov, MR; Makarova, ON; Krinsky, VI

Published Date

  • November 1993

Published In

Volume / Issue

  • 65 / 5

Start / End Page

  • 1775 - 1787

PubMed ID

  • 8298011

International Standard Serial Number (ISSN)

  • 0006-3495

Digital Object Identifier (DOI)

  • 10.1016/S0006-3495(93)81233-5

Language

  • eng

Conference Location

  • United States