RYR2 and Ventricular arrhythmia: Since the recognition of RyR2 as a gene responsible for CPVT [1], functional analyses have suggested that DADs following Ca2+ leakage from the sarcoplasmic reticulum (SR) are associated with ventricular arrhythmia in CPVT; however, the mechanisms underlying SR Ca2+ leak have not been elucidated.