Metformin has been recommended as the first-line therapy for type 2 diabetes.Besides its ideal glucose-lowering effect,metformin has also been shown to exert beneficial effects on cardiovascular system,including preventing the occurrence and progression of atherosclerosis,reducing risk for cardiovascular events,attenuating myocardial ischemia-reperfusion injury,improving ventricular remodeling,and slowing the progress of heart failure.The activation of adenosine monophosphate activated protein kinase (AMPK) signaling pathway plays a pivotal role in the protective cardiovascular effects resulted from metformin.