Initiation of re-entry in an excitable medium: structural investigation of cardiac tissue using a genetic algorithm.
The detailed mechanisms by which re-entry and ventricular fibrillation are initiated in the heart remain poorly understood because they are difficult to investigate experimentally. We have used a simplified excitable media computational model of action potential propagation to systematically study how re-entry can be produced by diffuse regions of inexcitable tissue. Patterns of excitable and inexcitable tissue were generated using a genetic algorithm. The inexcitable tissue was modeled in two ways: (i) diffusive, electrically connected but inexcitable tissue, or (ii) zero-flux, areas of tissue electrically disconnected in the same way as zero-flux boundary conditions. We were able to evolve patterns of diffuse inexcitable tissue that favored re-entry, but no single structure or pattern emerged. Diffusive inexcitable regions were inherently less arrhythmogenic than zero-flux inexcitable ones.
Scarle
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Department of Computer Science, University of Sheffield, Regent Court, 211 Portobello Street, Sheffield S1 4DP, United Kingdom.
Clayton
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RH
D000465:Algorithms; D000818:Animals; D001703:Biophysics / Q000379:methods*; D003198:Computer Simulation; D006321:Heart / Q000502:physiology*; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008954:Models, Biological; D008955:Models, Cardiovascular; D008957:Models, Genetic; D008962:Models, Theoretical; D009206:Myocardium / Q000473:pathology*