RYR2 and cardiac arrhythmia: Hyperphosphorylation of RyR2 has been implicated in the pathogenesis of various cardiac dysfunctions, including myocardial systolic and diastolic dysfunction, arrhythmias, and heart failure (Marx et al., 2000; Belevych et al., 2013; Do and Knollmann, 2025; Shan et al., 2010).