In human RyR2, nearly 300 pathogenic mutations have been reported as arrhythmogenic heart diseases, including catecholaminergic polymorphic ventricular tachycardia (CPVT)5–8, and idiopathic ventricular fibrillation (IVF)9–12. Here, RYR2 is linked to paroxysmal familial ventricular fibrillation.