Simulated dynamic interaction of coupled sinoatrial node pacemaker cell pairs

Previous modelling studied by other investigators indicates that electrotonic coupling between cells underlies mutual entrainment and synchronization of the intact sinus node. In this study, interaction between a pair of resistively coupled pacemaker cells was investigated using a complex, physiologically accurate model of the single sinoatrial node cell. Variation in intrinsic cycle length was achieved by multiplying the background sodium conductance g_b,Na by a constant modulating parameter (0<α⩽1.0). For each value of the modulating parameter a single cell was integrated until a steady state was achieved, at which point the model parameters were saved for use as initial conditions in the simulations of coupled cell pairs. The effect of cycle length and magnitude of coupling resistance on entrainment were investigated. Simulation results are presented demonstrating both simple and complex entrainment phenomena