RYR2 and catecholaminergic polymorphic ventricular tachycardia: Mutations that cause CPVT normally induce gain-of-function behaviour on RyR2 [2] resulting in excessive spontaneous Ca2+ release in cardiac myocytes in the form of Ca2+ sparks and Ca2+ waves that generate delayed afterdepolarizations (DADs) through the Na+/Ca2+ exchange (NCX) mechanism.