CASQ2 and catecholaminergic polymorphic ventricular tachycardia: β-adrenergic activation of the CASQ2 mutant myocyte in our model revealed three CPVT-related phenomena: (1) EADs, found at low frequency immediately after switching from rapid pacing, (2) alternans, during rapid pacing, and (3) alternative beat skipping, also observed in rapid pacing.