The authors report on a 47-years old woman with bacterial endocarditis involving both the mitral and aortic valves. At first echocardiographic examination, the mitral vegetation was small, while the aortic one was large highly mobile. Despite adequate antibiotic therapy, the aortic vegetation had become bigger and the valve regurgitation, initially mild to moderate, resulted severe and was associated with left heart failure. While awaiting surgery, the patient sustained an acute non Q wave myocardial infarction with ST segment elevation in inferior and anterolateral leads, complicated by ventricular arrhythmias. Thirty-six hours later, the patient received mitral and aortic valve replacement: at surgical view, the aortic vegetations was found to be very close to the right coronary orifice. After a period of further antibiotic therapy, the woman discharged and at a six months follow-up, she was fairly well. The authors review the mechanisms of acute coronary insufficiency in infective endocarditis and suggest an embolic pathogenesis in the case reported. Taking into account the possible life threatening embolic complications, it seems reasonable not to delay surgery when antibiotic therapy fails to reduce the size and mobility of valve vegetations.