Strikingly, this GM1869 substance exhibited its most pronounced effect on RyR2 activity in cardiomyocytes isolated from hearts of an in-depth characterized CPVT-susceptible RyR2R2474S/+ knockin mouse model (Lehnart et al, 2008) compared with WT littermate cardiomyocytes. Here, RYR2 is linked to catecholaminergic polymorphic ventricular tachycardia.