Unusual echocardiographic manifestation of pericardial effusion.

Echocardiographic and sector scanning examinations were performed in a patient with pericardial effusion. In addition to the demonstration of fluid posterior to the left ventricle and anterior to the right ventricle, as in most significant pericardial effusions, there was an echo-free space representing fluid recorded posterior to the left atrium. Several possible explanations of this finding are offered.