A computer model of dual AV nodal pathways: evidence for electrotonic interactions

In patients with atrioventricular (AV) nodal reentrant tachycardia, there exist two functional conducting pathways: a fast pathway with a larger effective refractory period, and a slow pathway with a shorter refractory period. Elimination of the slow pathway cures patients of their arrhythmia. It has been observed clinically that elimination of the slow pathway results in shortening of the effective refractory period of the fast pathway, the mechanism of which is not known. In a computer model of the AV nodes, the authors successfully tested the hypothesis that concealed conduction in the late-activating slow pathway exerts an electrotonic influence on the fast pathway, such that elimination of the slow pathway results in shortening of fast pathway action potential duration. The model consisted of resistively coupled elements exhibiting ionic current kinetics of calcium-driven action potentials