RYR2 and Prolonged QT interval: Both RYR2 R420W and S2246L are linked to catecholaminergic polymorphic ventricular tachycardia (CPVT) (35, 36); CALM1 N98S is linked to long QT syndrome, CPVT, idiopathic ventricular fibrillation, and sudden unexplained death (41).