Regulation of Electrical Coupling Between Bio-pacemaker and Ventricular Myocytes on Autonomous Signal Propagation: A Simulation Study

Experiments showed that the expression of connexin - Cx43 was suppressed in biological pacemakers (bio-pacemaker). Decreased Cx43 inhibited electrical coupling between bio-pacemakers and adjacent cardiac cells, which can maintain the synchronous pacemaking behaviour of bio-pacemaker. At the same time, moderate Cx43 is necessary to encourage autonomous electrical signal being propagated to non-rhythmic cardiac tissue. In this study, we simulated the electrical cell coupling among pacemaker myocytes (PMs) and ventricular myocytes in a two-dimensional idealized cardiac tissue model. We explored the effect of cell coupling pattern on the initiation of spontaneous signal in and the propagation capacity of the automaticity. If remaining cell coupling unchanged, the PMs tissue could not produce automaticity. When decreasing the coupling among PMs, PMs tissue presented synchronous pacemaking activity but the electrical signal could not propagate to the adjacent ventricular tissue. Then, according to the heterogeneity of intrinsic sinoatrial node, we divided PMs into central PMs and peripheral PMs. Only cell coupling of central PMs was decreased. In this way, PMs tissue could generate automatic pacemaking activity which could drive ventricular tissue. Our study might provide new sight into the electrical propagation mode of bio-pacemaker.