RYR2 and catecholaminergic polymorphic ventricular tachycardia: Similarly, murine cardiac muscle showed reduced INa when SR Ca2+ release was enhanced by Epac activation (King et al., 2013; Valli et al., 2018), or in the pro-arrhythmic gain of function RyR2-P2328S genetic modification associated with catecholaminergic polymorphic ventricular tachycardia, with implications for anti-arrhythmic therapy (Huang, 2017; Zhang et al., 2011; 2013).