TMEM43 and arrhythmogenic right ventricular cardiomyopathy: The class Ic/IVb antiarrhythmic drug flecainide has emerged as an effective alternative in patients with catecholaminergic polymorphic ventricular tachycardia, a genetic arrhythmic disorder of RYR2 hyperactivity.[27, 28, 29] The hyperactive RYR2 phenotype in ARVC iPSC‐CMs prompted us to investigate whether flecainide could suppress the impact of TMEM43‐P386S in ARVC iPSC‐CMs.