CaMKII‐enhanced diastolic Ca2+ leakage also hyperphosphorylates RyR, which leads to early afterdepolarizations.26 Ca2+ sparks represent a major release of Ca2+ in cardiomyocytes during excitation‐contraction coupling.19 Ca2+ sparks are stochastic activations of a cluster of RyR2s that are organized into a Ca2+‐release unit.27 Diabetes mellitus rats exhibit a higher incidence and frequency of Ca2+ sparks in cardiomyocytes,28 which leads to changes in Ca2+ handling and myocardial dysfunction. The gene discussed is RYR2; the disease is diabetes mellitus.