To test this hypothesis, we studied Ca2+ sparks and waves in isolated saponin-permeabilized ventricular myocytes from two CPVT mouse models (Casq2-/- and RyR2-R4496C+/-), wild-type (WT) mice, and WT rabbits. Here, CASQ2 is linked to catecholaminergic polymorphic ventricular tachycardia.