An experience with penetrating cardiac injuries between 1974 and 1977 has permitted designation of particular findings as indications for emergent operations and appropriate therapeutic approaches. Of the 46 patients with cardiac trauma, 28 suffered gunshot wounds. Seventeen patients died, and 14 of the deaths occurred as a result of asystole, ventricular fibrillation or exsanguination during operation. Two patients died of neurologic sequelae following successful cardiac repair, and one died secondary to injury not disclosed by physical examination or roentgenogram. The surviving 29 patients had five major complications. Sepsis, organ system failure and cardiac defects rarely occurred despite rapidly performed thoracotomy and severe shock. Since delayed operation has been uniformly associated with adverse outcome and because postoperative complications of emergent pericardial exploration are mild, the following conclusions have been reached: 1) Mediastinal entrance wounds, severe hypotension and signs of cardiac tamponade arc demonstrative of cardiac trauma. Therefore, virtually any combination of these physical signs mandates pericardial exploration. 2) Subxiphoid or transdiaphragmatic exploration (during laparotomy) of the pericardium has been valuable in diagnosis of suspected heart wounds. 3) Emergent cardiorrhaphy is the treatment of choice. Pericardiocentesis is at best only temporarily effective. Thoracotomies performed in the emergency room were uniformly unsuccessful. If possible, cardiorrhaphy should be done in the operating room. 4) Median sternotomy is the approach of choice. 5) The basic principles of management of cardiac injury are rapid diagnosis, relief of tamponade, control of hemorrhage, repair of cardiac defects and restoration of blood volume.