RYR2 and catecholaminergic polymorphic ventricular tachycardia: CPVT is a heterogeneous genetic disease, including autosomal dominant mutations in ryanodine receptor type 2 (RyR2, CPVT1), autosomal recessive mutations in calsequestrin 2 (CASQ2, CPVT2), and more rarely mutations in triadin or calmodulin.