Oscillation cessation due to removal of Na+ current restored by external noise stimulation

Abstract

In this study, a complete two-dimensional anatomical model of the rabbit heart was constructed by Zhang et al. The positive effects of external noise stimulation on cardiac pacemaking and conduction have been studied using computer simulations. Our results show that: 1) the slower pacemaking rate or even oscillation cessation, which is induced by the removal of $i_{Na}$ from the sinoatrial node or a decrease in the active sinoatrial node cell population, can be recovered by adding external noise. 2) Compared to the effect of $i_{Na}$ removal alone, the combined effect of $i_{Na}$ and cell death had a greater impact on slowing down the pacemaking rate. These phenomena indicate that external stimuli play an important role in controlling the initiation and conduction of sinoatrial node pacemaker activity, and that the aging heart may experience obstruction of sinus node conduction and even sudden cardiac death due to decreased cell membrane $i_{Na}$ or partial myocardial cell death. Our results provide insights into the intrinsic mechanisms underlying electroshock healing in some heart diseases.