A 66-year-old man suddenly fell into a state of shock on his way back to his room after emergency coronary angiography and intracoronary thrombolysis for acute myocardial infarction. Both echocardiography and pericardiocentesis suggeted a diagnosis of cardiac rupture. The patient was transferred to an operating room with a percutaneous cardiopulmonary support system (PCPS) and intraaortic balloon pumping. Following thoracotomy and release of cardiac tamponade, blow out rupture of the left ventricular free wall was detected. The rupture was repaired using triple mattress sutures by reinforcing with felt pledgets. An infarctectomy was not added and cardiopulmonary bypass was not used. Postoperative recovery of cardiac function was satisfactory and the left ventricular ejection fraction after 2 months was 35%. PCPS and consecutive surgical therapy are effective for the treatment of blow out rupture of the left ventricular free wall.