Reentry produced by small-scale heterogeneities in a discrete model of cardiac tissue

7th International Workshop on MUlti-Rate Processes & HYSteresis; 2nd International Workshop on Hysteresis and Slow-Fast Systems

Alonso, Sergio^1 ; Bär, Markus^2

Department of Applied Physics, Universitat Politcnica de Catalunya - BarcelonaTech, Barcelona, Spain^1

Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, Berlin

10587, Germany^2

关键词: Conducting materials;    Heterogeneous region;    Homogeneous tissues;    Ischemic conditions;    Percolation thresholds;    Small-scale heterogeneity;    Two Dimensional (2 D);    Two-dimensional networks;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/727/1/012002/pdf
DOI  :  10.1088/1742-6596/727/1/012002

来源: IOP

【 摘 要 】

Reentries are reexcitations of cardiac tissue after the passing of an excitation wave which can cause dangerous arrhythmias like tachycardia or life-threatening heart failures like fibrillation. The heart is formed by a network of cells connected by gap junctions. Under ischemic conditions some of the cells lose their connections, because gap junctions are blocked and the excitability is decreased. We model a circular region of the tissue where a fraction of connections among individual cells are removed and substituted by non-conducting material in a two-dimensional (2D) discrete model of a heterogeneous excitable medium with local kinetics based on electrophysiology. Thus, two neighbouring cells are connected (disconnected) with a probability φ (1 - φ). Such a region is assumed to be surrounded by homogeneous tissue. The circular heterogeneous area is shown to act as a source of new waves which reenter into the tissue and reexcitate the whole domain. We employ the Fenton-Karma equations to model the action potential for the local kinetics of the discrete nodes to study the statistics of the reentries in two dimensional networks with different topologies. We conclude that the probability of reentry is determined by the proximity of the fraction of disrupted connections between neighboring nodes ("cells") in the heterogeneous region to the percolation threshold.