Effect of Gap Junction Distribution, Size, and Shape on the Conduction Velocity in a Cell-by-Cell Model for Electrophysiology

Gap junction arrangement is a major determinant of cardiac conduction velocity. Importantly, structural remodeling of the myocardium may lead to pathological CV and a pro-arrhythmic substrate. In this work we aim at quantifying the side-to-side conduction velocity in a sub-micrometer model of the myocardium that accounts for gap junctions. We consider the Extracellular-Membrane-Intracellular (EMI) model, which describes the evolution of the electric potential within each cell and in the extracellular space. For the solution of the model, we propose a boundary integral formulation of the cell-to-cell model that leads to small system of ODEs. We study several configurations of lateral gap junction distribution, as well as different shapes and sizes of the cell-tocell connection. We find that irregular positioning of gap junctions from cell to cell is of utmost importance to obtain realistic CV values, while gap junction’s shape is of secondary importance.