Chaos 2020

Universal mechanisms for self-termination of rapid cardiac rhythm

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Our heart contains excitable cells. These can excite and display wave-like patterns. Under certain circumstances, these waves can become circular. Such circular waves can lead to serious impairment or even death. Here, we looked at the stability of such circulating waves.

A simplified version of a circulating wave is a strip of tissue where you excite the cells on one side, wait until the wave travels to the other side, and upon receiving a signal at that end, re-excite the beginning of the strip. This re-excitement can be done with certain delays, which will affect the stability of the circulating wave. For long delays, rapid circulating rhythms can be sustained, whereas for shorter delays, the waves start but stop again spontaneously.

Figure 1: Typical traces of action potential duration (blue) and conduction time (red). Mathematical modeling curves are present as well (black). 

 In this study, we made use of an experimental model of such a strip of tissue by stimulating mouse hearts from one side (with the use of optogenetics) and recording the signal on the other side (from apex to base). It was observed that right before termination, the data showed oscillating patterns. This data was analyzed mathematically, and a new theory was postulated that can explain the observed alternations in conduction velocity and action potential duration (i.e. a measure of the length of excitation of a wave). This theory could also predict when the bursts of waves would stop. It was proposed that this illustrates a possible -universal mechanism that exist in biological systems for the self-termination of circulating waves. 

Journal info

Article type:  Research article
Impact factor: 3.741
ISSN: 1054-1500 (print); 1089-7682 (web)

Chaos: An Interdisciplinary Journal of Nonlinear Science is a peer-reviewed journal founded in 1991 to promote the understanding of nonlinear dynamics and the evolution of complex systems and describe their manifestations in a manner comprehensible to researchers from a broad spectrum of disciplines.

We encourage authors to submit manuscripts on nonlinear phenomena in all disciplines of science and engineering. We also encourage selected articles on the more mathematical aspects of nonlinear systems, provided that these meet the criteria of the journal and are accessible to the broad nonlinear community. In terms of methodologies, analytical, computational, and experimental studies are all equally welcome.