Two-dimensional echocardiography in cardiac tamponade occurring after cardiac surgery.

Cardiac tamponade is an important complication after cardiac surgery, yet little has been published on the echocardiographic diagnosis of this situation. The two-dimensional echocardiograms of 11 patients who required surgical relief of cardiac tamponade complicating cardiac surgery were therefore reviewed. Four had nonloculated pericardial effusions surrounding both ventricles. The other seven patients had a loculated posterior pericardial effusion; in three of these the effusion altered left ventricular posterior wall contour so that it was concave toward the effusion in the long-axis view; in two, a strikingly abnormal motion of the left ventricular posterior wall was noted, such that the width of the posterior pericardial space diminished in systole and widened abruptly in early diastole. The quantity of pericardial contents (fluid, blood or clot) evacuated surgically was smaller than usually encountered in patients with tamponade due to various "medical" conditions. Thus, unlike tamponade with other pericardial effusions, tamponade after cardiac surgery is due to a pericardial effusion that is smaller in volume, often loculated posteriorly and associated with certain unique two-dimensional echocardiographic features.