Coexisting chaotic and multi-periodic dynamics in a model of cardiac alternans

TL;DR

This paper investigates the coexistence of chaotic and multi-periodic dynamics in a model of cardiac alternans, revealing complex spatiotemporal behaviors linked to arrhythmogenesis and validating findings with a detailed ionic model.

Contribution

It demonstrates the coexistence of chaotic and multi-periodic dynamics in a calcium-driven cardiac model, highlighting spatial variations and validating with ionic model simulations.

Findings

Coexistence of chaos and multi-periodicity in cardiac tissue model

Dynamics vary spatially, with low-period near nodes and chaos elsewhere

Similar behaviors observed in detailed ionic model

Abstract

The spatiotemporal dynamics of cardiac tissue is an active area of research for biologists, physicists, and mathematicians. Of particular interest is the study of period-doubling bifurcations and chaos due to their link with cardiac arrhythmogenesis. In this paper we study the spatiotemporal dynamics of a recently developed model for calcium-driven alternans in a one dimensional cable of tissue. In particular, we observe in the cable coexistence of regions with chaotic and multi-periodic dynamics over wide ranges of parameters. We study these dynamics using global and local Lyapunov exponents and spatial trajectory correlations. Interestingly, near nodes -- or phase reversals -- low-periodic dynamics prevail, while away from the nodes the dynamics tend to be higher-periodic and eventually chaotic. Finally, we show that similar coexisting multi-periodic and chaotic dynamics can also be observed in a detailed ionic model.