RYR2 and catecholaminergic polymorphic ventricular tachycardia: 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).