In Silico Simulation of Mouse Atrioventricular Conduction Including Sinus Node and Atrial Myocardium

This work aims to investigate mouse atrioventricular node conduction using in silico simulations. First, a 1D cable composed of sinus node, atrium, and atrioventricular node cells was simulated to analyze conduction under healthy and If block conditions. No appreciable impairments in atrioventricular conduction were observed, but a surprising increase in atrioventricular node conduction velocity was noted. Next, the focus shifted to the atrioventricular node, with increased resolution achieved by simulating the fast and slow pathways. The fast pathway was hypothesized to consist of half atrial and half atrioventricular node cells, while the slow pathway was made entirely of nodal cells. This model demonstrated the capability of early His activation through the fast pathway, aligning with current knowledge of the mammalian atrioventricular node. Finally, a more complex 2D setup was tested to simulate Koch’s triangle in the mouse, including the main atrioventricular node landmarks. In this model, two distinct insulated pathways were not observed, but a slight delay between upper and lower His activation was found, with earlier activation of the upper region.