Echocardiographic mimicry of pericardial effusion.

Echocardiography is a sensitive technique for the detection of pericardial effusion, but the abnormal echocardiographic patterns seen with effusions are not, however, entirely specific for that diagnosis. This study describes four patients in whom anatomic structures, a coronary artery to coronary sinus fistula (one case) and tumors metastatic to pericardium (three cases), produced posterior and, in two cases, anterior spaces compatible with pericardial fluid. Echocardiographic patterns mimicking pericardial effusion have previously been reported in patients with anatomic abnormalities such as mitral anular calcification, pleural effusions, left atrial enlargement, anterior mediastinal or pericardial tumors, foramen of Morgagni hernia and pseudoaneurysm of the left ventricle. It appears that structures of fluid or tissue density, interposed between the heart and the airfilled lung, can produce echocardiographic patterns simulating pericardial effusion.