Abstract
Myocardial ischemia occurs when blood flow to the heart is reduced, preventing the heart muscle from receiving enough oxygen required for survival. Several anatomical and electrophysiological changes occur at the ischemic core (IC) and border zone (BZ) during myocardial ischemia, for example, gap junctional remodeling, changes in ionic channel kinetics and electrophysiologic changes in cell excitability, which promote the development of cardiac arrhythmia. Ephaptic coupling (EpC), which is an electrical field effect developed in the shared cleft space between adjacent cells, has been suggested to rescue the conduction when gap junctions are impaired, such as myocardial ischemia. In this manuscript, we explored the impact of EpC, electrophysiological and anatomical components of myocardial ischemia on reentry termination during non-ischemic and ischemic condition. Our results indicated that EpC and BZ with complex geometry have opposite effects on the reentry termination. In particular, the presence of homogeneous EpC terminates reentry, whereas BZ with complex geometry alone facilitates reentry by producing wave break-up and alternating conduction block. The reentry is terminated in the presence of homogeneous or heterogeneous EpC despite the presence of complex geometry of the BZ, independent of the location of BZ. The inhibition of reentry can be attributed to a current-to-load mismatch. Our results points to an antiarrhythmic role of EpC and a pro-arrhythmic role of BZ with complex geometry.
Highlights
Myocardial ischemia is a medical condition resulting from critical coronary artery obstruction, which can lead to serious complications, including but not limiting to heart attack, arrhythmia and heart failure
To explore the impact of homogeneous Ephaptic coupling (EpC) on the evolution of reentry in normal zone (NZ), we used this self-sustained reentry as initial conditions to generate Fig 3, S1 and S2 Figs to ensure that our results are independent of reentry initiation methods
Since the reduction in gap junctional coupling and cell swelling are both heterogeneous in the heart during myocardial ischemia, we explored the interplay between heterogeneous EpC and border zone (BZ)
Summary
Myocardial ischemia is a medical condition resulting from critical coronary artery obstruction, which can lead to serious complications, including but not limiting to heart attack, arrhythmia and heart failure. It is one of the leading causes of sudden cardiac death worldwide. Altered electrophysiological and anatomical properties that occurred during myocardial ischemia lead to significant changes in the shape of action potential and its propagation [1–3]. Mechanisms of reentry termination collection and analysis, decision to publish, or preparation of the manuscript
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