Figure 4.

Higher probability of EAD induction by coupling multiple myofibroblasts to a single myocyte. A patch-clamped myocyte was exposed to H₂O₂ to induce bradycardia-dependent EADs at PCL 6 s, which were then suppressed at PCL 1 s. Coupling the myocyte (MC) to one myofibroblast (MF, with C_f 50.0 pF, G_j 3.0 nS, E_f −25 mV) depolarized the myocyte and shortened APD (middle trace), but did not cause EADs to reappear. However, when the myocyte was coupled to two myofibroblasts in parallel (effectively increasing C_f to 100 pF and G_j to 6 nS), EADs and repolarization failure ensued (lower trace).