Fig. 2.

Effects of metformin on ventricular arrhythmias. Ischemia causes reduction in myocardial ATP and finally results in ventricular fibrillation. Chronic metformin use exerts its energy guardian effects mainly via AMPK activation. Additionally, metformin prevents QT interval prolongation, QT dispersion, and conduction velocity delay by regulating microRNA-1 and L-type calcium channels. Only the combination of metformin and vildagliptin could increase p-Cx43 and subsequently reduce ventricular fibrillation. Green rectangle and arrow shows protective mechanisms of metformin