Late cardiac tamponade after open heart surgery.

Delayed cardiac tamponade after open heart surgery is relatively uncommon, but constitutes a life-threatening condition that must be diagnosed and managed promptly. We report 21 patients who developed cardiac tamponade 5 to 53 days after open heart operations. Possible etiological factors included anticoagulant therapy (19 patients), excessive mediastinal drainage in the postoperative period (10 patients), postpericardiotomy syndrome (4 patients), and coagulation disorders (1 patient). The clinical presentation was insidious and the diagnosis was often difficult to establish at the outset. A high index of clinical suspicion and echocardiography were the most reliable means to reach an early diagnosis. Twenty patients in whom delayed tamponade was suspected were operated and all of them survived. In one patient tamponade was not diagnosed antemortem and he died; on autopsy left heart compression by a large loculated clot was found. Decompression of the pericardial space can be accomplished by pericardiocentesis or by surgical means (subxiphoid pericardiotomy, median sternotomy, or thoracotomy). Although pericardiocentesis alone may be effective, mainly when the postpericardiotomy syndrome is the suspected etiology, we recommend open procedures since the presence of blood clots and adhesions has been a frequent finding.