A 60-year-old Asian man who suffered penetrating thoracoabdominal injuries was admitted to our hospital in a state of shock. Because the results of a chest computed tomogram (CT) strongly suggested a left ventricular injury, an emergency thoracotomy was performed. A laceration of the left ventricle (3 cm) was sutured and was closed without cardiopulmonary bypass, and coexisting lacerations of the superior mesenteric artery (SMA) and small bowel were surgically repaired. During the procedure, cardiac arrest occurred, but the patient recovered without any apparent neurologic deficit. Postoperative examinations using echocardiogram, CT, and cardiac catheterization revealed a delayed rupture of the left ventricle. On the 28th day after surgery, he was transferred to another hospital for elective cardiac surgery. Primary management of penetrating cardiac injury is discussed in this report.