RYR2 and catecholaminergic polymorphic ventricular tachycardia: Abnormal Ca2+ release can arise from cardiac ryanodine receptor-2 (RyR2) mutations or a loss of calsequestrin-2 (CSQ2) (Priori & Chen 2011), potentially providing arrhythmic triggers (Mackenzie et al. 2001, 2004, Bootman et al. 2006, Zhang et al. 2010), thereby leading to catecholaminergic polymorphic ventricular tachycardia (CPVT) (Priori & Chen 2011, Zhang et al. 2013a).