RYR2 and Arrhythmia: Others and we have previously demonstrated that activated CaMKII, a pro-arrhythmic signaling molecule, is critically involved in phosphorylation of RyR2-2815 and PLB-Thr17 (RyR2815-P, PLB17-P), which results in sensitized RyR channels that in turn leads to triggered activities and arrhythmia initiation due to diastolic SR Ca leak in pathologically altered ventricles (Hoch et al., 1999; Maier et al., 2003; Zhang et al., 2003; Ai et al., 2005; Yeh et al., 2008; Greiser et al., 2009; Sossalla et al., 2010; Respress et al., 2012).