Cardiac tamponade complicating closure of a median sternotomy.

A case of intraoperative cardiac tamponade manifested during closure of a median sternotomy is presented. We postulate that cardiac tamponade was caused by acute dilatation of the cardiac chambers as a result of intraoartic balloon pumping in a patient with aortic and mitral regurgitation. It has been shown experimentally that acute rises in ventricular end-diastolic pressure result in increased intrapericardial pressure and that if a certain point on the pericardial pressure-volume curve is reached, cardiac tamponade will occur. Sternotomy closure was accomplished easily as soon as the need for intra-aortic balloon pumping diminished.