Simulation of effects of TBX18 on the pacemaker activity of human ventricular cells

Transcription factor TBX18 could reduce the electrical coupling of ventricular myocytes and slow the electrical propagation, leading to pacemaker activity. In this article, the effect of TBX18 was analyzed by modulating coupling conductance (diffusion coefficient) and we found that with the decreasing of coupling, the pacemaker activity of ventricle increased. The first pacing time decreased with the reduction of coupling. However, when coupling conductance was lower than a critical value, the automatic excitation could not propagate, although the pacemaker worked robustly. Once the working myocytes could be driven, the pacemakers with different coupling conductance made no significant difference. Action potentials (APs) of pacemaker cells and normal cardiac myocytes at the same coordinates were similar for different coupling.