Key result
Proximity of recovery levels to excitation thresholds determines transition to propagation block and alternans.
Critical propagation of excitation waves determines conditions for transition to unstable rhythms, providing insights into mechanisms of unstable cardiac rhythms.
Should not yet change clinical arrhythmia management; hypothesis-generating for wave propagation mechanisms and leaves open human translation.
BACKGROUND: Duration and speed of propagation of the pulse are essential factors for stability of excitation waves. We explore the propagation of excitation waves resulting from periodic stimulation of an excitable cable to determine the minimal stable pulse duration in a rate-dependent modification of a Chernyak-Starobin-Cohen reaction-diffusion model. RESULTS: Various pacing rate dependent features of wave propagation were studied computationally and analytically. We demonstrated that the complexity of responses to stimulation and evolution of these responses from stable propagation to propagation block and alternans was determined by the proximity between the minimal level of the recovery variable and the critical excitation threshold for a stable solitary pulse. CONCLUSION: These results suggest that critical propagation of excitation waves determines conditions for transition to unstable rhythms in a way similar to unstable cardiac rhythms. Established conditions were suitably accurate regardless of rate dependent features and the magnitude of the slopes of restitution curves.
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Starobin et al. (2009) studied Excitable medium (computational model). Periodic stimulation in a modified Chernyak-Starobin-Cohen reaction-diffusion model was evaluated on Stability of excitation wave propagation. The transition from stable propagation to propagation block and alternans in an excitable medium is determined by the proximity between the minimal recovery variable level and the critical excitation threshold.
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