Abstract
Spatially discordant alternans is a widely observed pattern of voltage and calcium signals in cardiac tissue that can precipitate lethal cardiac arrhythmia. Using spatially coupled iterative maps of the beat-to-beat dynamics, we explore this pattern’s dynamics in the regime of a calcium-dominated period-doubling instability at the single-cell level. We find a novel nonlinear bifurcation associated with the formation of a discontinuous jump in the amplitude of calcium alternans at nodes separating discordant regions. We show that this jump unidirectionally pins nodes by preventing their motion away from the pacing site following a pacing rate decrease but permitting motion towards this site following a rate increase. This unidirectional pinning leads to strongly history-dependent node motion that is strongly arrhythmogenic.
Keywords
unidirectional pinning, spatialy discordant alternans, nonlinear bifurcation, cardiac tissue, heart muscle
Subject Categories
Hysteresis, Myocardium
Disciplines
Physics
Publisher
American Physical Society
Publication Date
3-8-2012
Rights Information
Copyright (2012) American Physical Society.
Rights Holder
American Physical Society
Recommended Citation
Skardal, Per S.; Karma, Alain; and Restrepo, Juan G., "Unidirectional pinning and hysteresis of spatially discordant alternans in cardiac tissue" (2012). Physics Faculty Publications. Paper 519.
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Notes
Originally published in Physical Review Letters v.108 (2012): 108103. DOI: 10.1103/PhysRevLett.108.108103