GJA1 and Ventricular arrhythmia: In mice, myocardial MMP-9 inhibition modulates calcium homeostasis and reduces calcium leakage to prevent ventricular arrhythmia (Weng et al., 2016) and its overexpression mediates gap junction (GJ) electrical uncoupling induced by Cx43 decreases in rat (Li et al., 2019).