A sinus of Valsalva aneurysm (SVA) is a rare aortic disease that may be congenital or acquired. Patients with an intact SVA are usually asymptomatic, whereas a ruptured SVA may cause acute chest pain and dyspnea. We present a rare case of acute ST-elevation myocardial infarction and cardiogenic shock in a 51-year-old man. Emergency coronary angiography revealed a giant aneurysm with an absence of flow in the right coronary artery. Both two-dimensional echocardiography and computed tomography angiography showed a giant right SVA, which ruptured into the pericardial sac and led to extrinsic compression of the right coronary artery. Surgical repair combined with coronary bypass grafting was performed. Unfortunately, the patient died from low cardiac output syndrome and postoperative multiple organ failure. This case highlights that the possibility of SVA rupture should be considered in acute myocardial infarction cases and that echocardiography and coronary computed tomography angiography are important in providing an accurate and rapid SVA diagnosis.