Calcium dysregulation underlies phenotypic diversity in LQT2: Insights from induced pluripotent stem cell-derived cardiomyocytes of a KCNH2 p.Y427H family trio

Figure 5 Arrhythmogenic behavior of family trio induced pluripotent stem cell-derived cardiomyocytes. A: Representative early afterdepolarizations under 0.5-Hz pacing and spontaneous rhythms (a1). Ventricular tachycardia-like triggered arrhythmias under spontaneous rhythms (a2). Restoration of a relatively regular rhythm after instantaneous administration of 300 nmol/L nifedipine (a3); B: Representative early afterdepolarizations and triggered arrhythmias observed under spontaneous rhythms in multi-electrode array recordings (b1). Restoration of a relatively regular rhythm after instantaneous administration of 300 nmol/L nifedipine (b2); C: Representative and statistical analysis of action potential duration shortening by nifedipine under 0.5-Hz pacing in patch-clamp recordings (c1). Representative and statistical analysis of corrected field potential duration shortening by nifedipine under spontaneous rhythms in multi-electrode array recordings (c2). Data represent n = 15 and induced pluripotent stem cell-derived cardiomyocytes from 3 independent differentiations. EADs: Early afterdepolarizations; VT: Ventricular tachycardia; TAs: Triggered arrhythmias; APD: Action potential duration; cFPD: Corrected field potential duration.