The incidence and natural history of pericardial effusion after cardiac surgery--an echocardiographic study.

One hundred twenty-two consecutive patients (104 men; 18 women) were studied to determine the incidence and natural history of pericardial effusion occurring 2, 5, 10, and 20 to 50 days after cardiac surgery. Three patients had pericardial effusions before and 103 patients (91 men; three women) had effusions after surgery. Effusions were first recorded on the second postoperative day in 72 patients, on the fifth postoperative day in 29 patients, and on the tenth postoperative day in two patients. In 96 of these patients, effusions reached their maximum size by postoperative day 10. Of the 103 patients with effusions, 66 (64%) were followed to complete resolution. A specific pattern was observed in most resolving effusions. The echo-free space diagnostic of pericardial effusion became progressively more echo-dense as the effusion diminished in size. As the effusion became echo-dense, the posterior pericardium, which had been motionless, resumed its normal systolic anterior motion. One patient developed cardiac tamponade on postoperative day 3. We conclude that pericardial effusion occurs frequently after cardiac surgery, but that associated complications are rare.