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Spiral waves are stable in discrete element models of two-dimensional homogeneous excitable mediaThe spontaneous breakup of a single spiral wave of excitation into a turbulent wave pattern has been observed in both discrete element models and continuous reaction-diffusion models of spatially homogeneous 2D excitable media. These results have attracted considerable interest, since spiral breakup is thought to be an important mechanism of transition from the heart rhythm disturbance ventricular tachycardia to the fatal arrhythmia ventricular fibrillation. It is not known whether this process can occur in the absence of disease-induced spatial heterogeneity of the electrical properties of the ventricular tissue. Candidate mechanisms for spiral breakup in uniform 2D media have emerged, but the physical validity of the mechanisms and their applicability to myocardium require further scrutiny. In this letter, we examine the computer simulation results obtained in two discrete element models and show that the instability of each spiral is an artifact resulting from an unphysical dependence of wave speed on wave front curvature in the medium. We conclude that spiral breakup does not occur in these two models at the specified parameter values and that great care must be exercised in the representation of a continuous excitable medium via discrete elements.
Document ID
20040088965
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Feldman, A. B.
(Harvard University-Massachusetts Institute of Technology, Division of Health Sciences and Technology Cambridge 02139, United States)
Chernyak, Y. B.
Cohen, R. J.
Date Acquired
August 21, 2013
Publication Date
June 1, 1998
Publication Information
Publication: International journal of bifurcation and chaos in applied sciences and engineering
Volume: 8
Issue: 6
ISSN: 0218-1274
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAGW-3297
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cardiopulmonary
Non-NASA Center

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