RYR2 and catecholaminergic polymorphic ventricular tachycardia: Our data suggest that, as in CPVT, the ectopic beats in heart failure may also be generated at the Purkinje–myocardial junction via a heretofore unrecognized tissue mechanism, whereby subthreshold membrane depolarizations caused by spontaneous RyR2 Ca release in the VM generate full APs in the adjacent PF.