RYR2 and catecholaminergic polymorphic ventricular tachycardia: Since both proteins are major players in (E-C) coupling, the functional derangements in intracellular Ca2+ handling resulting from the mutated RyR2 and CASQ2 may cause delayed afterdepolarizations (DADs) and triggered arrhythmias which constitute the electrophysiological mechanism underlying CPVT 1–3.