Regional variation of gap junction conductance on reentrant arrhythmia

Arrhythmia generating conditions like ventricular hypertrophy, myocardial infarction or ischemia modify the intercellular coupling by modifying the conductance of gap junctions in the normal electric propagation pathway of the heart. A discrete ventricular cell network of 100x100 cells interconnected using resistive gap junctions is simulated to study the effect of size, shape and position of inhomogeneity as well as the value of gap junction conductance of inhomogeneity on the occurrence of reentrant arrhythmia. In addition to lowering the conduction, a unidirectional block is also created using exactly timed stimulation inputs thus setting the ideal conditions for a reentrant activation to arise from the zone of varied gap junction conductance. The shape and endurance of generated reentrant waves is analyzed. The electrical activity of each cell is simulated using the Ten Tusscher-Panfilov 2006 model. Simulation results show that the positions as well as the size of the inhomogeneity play a major role in the creation of reentrant waves while the shape of the inhomogeneity does not have a significant effect. Also, reentrant waves occur at a certain level of decoupling. Too much or too little decoupling also doesn't induce reentrant waves. The amplitude and duration of action potential is heavily dependent on the gap junction conductance.