Subepicardial aneurysm after anticoagulant therapy for a mural thrombus following anterior myocardial infarction

A subepicardial aneurysm became evident in a male patient after anticoagulant therapy. On admission, it appeared to be an old anterior infarction accompanied by a mural thrombus. After warfarin administration, the thrombus disappeared and an echo-free space emerged outside the apical myocardial wall. The echo-free space communicated with the left ventricular cavity through the apical myocardial wall. Emergency surgery was undertaken and the patient survived. The aneurysm was covered with epicardium and there was an endomyocardial rupture of the muscle in the apical wall, which was the entrance of the aneurysm. This case suggests that cautious follow-up with echocardiography is necessary when anticoagulant therapy is selected for thrombi following myocardial infarction.