RYR2 and catecholaminergic polymorphic ventricular tachycardia: As shown for the familial arrhythmia disorder, catecholaminergic polymorphic ventricular tachycardia (CPVT) [10,11], genetic mutations in RyR2 or its auxiliary protein CASQ2, compromise the ability of the RyR2 channels to stay appropriately closed during the diastolic period, thereby resulting in aberrant, spontaneous SR Ca release.