RAPGEF3 and Ventricular arrhythmia: Moreover, Rajesh Prajapati et al. demonstrated that the sympathetic activation-induced sarcoplasmic reticulum (SR) Ca2+ leak was reduced in cardiac myocytes of Epac1−/− mice, and a selective Epac1 inhibitor, CE3F4, can prevent atrial and ventricular arrhythmias in mice (Prajapati et al., 2019a).