RYR2 and ventricular tachycardia: Thus, the R-Carvedilol (R-Carv) enantiomer does not appear to have β-blocking activity [18,20], but Zhang et al. [21] demonstrated that it suppresses ventricular tachycardia in mice with the CPVT-causing RyR2 mutation (R4496C) by directly modifying RyR2 gating without lowering the heart rate or blood pressure.