The class Ic anti-arrhythmic drug flecainide, commonly known as an inhibitor of membrane Na+ channels, has been shown to have clinical efficacy for preventing ventricular arrhythmias in CPVT patients carrying either Casq2 or RyR2 mutations (Watanabe et al., 2009). Here, CASQ2 is linked to catecholaminergic polymorphic ventricular tachycardia.