RYR2 and atrial fibrillation: Several mechanisms have subsequently been proposed as contributing to enhanced RyR2 activity in AF, including increased SR load (Voigt et al., 2014) and post-translational modification of RyR2, such as phosphorylation and oxidation which increase channel open probability (Xiao et al., 2007; Neef et al., 2010; Voigt et al., 2012; Xie et al., 2015; Waddell et al., 2016).