RYR2 and heart failure: We have, with the help of mathematical modeling, linked this “dispersion” of RyR clusters and CRUs to slowing of spark kinetics during heart failure, as Ca2+ release spreads between sequentially activated clusters (Louch et al., 2013; Kolstad et al., 2018), desynchronization of the Ca2+ transient, and slowing of cardiomyocyte contraction (Bøkenes et al., 2008).