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DY: Fachverband Dynamik und Statistische Physik
DY 51: Focus Session: Nonlinear Dynamics of the Heart II (joint session DY/BP)
DY 51.3: Vortrag
Donnerstag, 19. März 2020, 14:45–15:00, ZEU 118
Simple mechanism for low-energy antifibrillation pacing — Pavel Buran, Thomas Niedermayer und •Markus Bär — Physikalisch-Technische Bundesanstalt (PTB), Berlin
Rotating excitation waves and electrical turbulence in cardiac tissue are associated with arrhythmias such as life-threatening ventricular fibrillation. Experimental studies have shown that a sequence of low-energy electrical far-field pulses is able to terminate fibrillation with less energy than a single large energy shock [1]. Previous theoretical approaches to understand this low-energy antifibrillation pacing (LEAP) have often focused on unpinning and removal of a small number of rotating spirals in quasi-two-dimensional situations. These theories, however, cannot explain the defibrillation of spatiotemporal chaos. Based on a systematic simulation study, we present an alternative mechanism for the success of LEAP in two dimensions, which explains both, the termination of stable spirals as well as spatiotemporal chaos. It turns out that actually each pulse during LEAP annihilates all excitation fronts, however, that new fronts could arise at the borders between refractory and excitable parts of the tissue. The success probability of each individual pulse can thus be simply interpreted as the probability that no new front arises. Furthermore, we will show that the success probability depends exponentially on the total length of these refractory boundaries and that successful LEAP is characterized by pulses causing a gradual decrease of this length simultaneously increasing the success probability of subsequent pulses until complete defibrillation.
[1] Luther et al., Nature 475, 235-239 (2011)