RYR2 and atrial fibrillation: The molecular properties of RyR2 carrying CPVT and/or AF mutations that lead to diastolic Ca2+ leak are frequently studied using RyR2 channels expressed in HEK 293 cells (Jiang et al., 2005; Liu et al., 2013; Meli et al., 2011; Paavola et al., 2007).