RYR2 and catecholaminergic polymorphic ventricular tachycardia: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a relatively rare inherited arrhythmic disease that causes sudden cardiac death, and is caused by mutations in the cardiac ryanodine receptor (RyR2) or sarcoplasmic reticulum protein calsequestrin 2 gene (CASQ2).