Localization of pericardial effusion with wide angle phased array echocardiography.

Twenty-eight patients with proved pericardial effusions were studied in the left lateral decubitus position with an 80 degrees phased array sector scanner to determine the distribution of pericardial effusions of various sizes. Twenty-one of 28 patients were studied 2 minutes after assuming the sitting position to determine the change in the distribution of the effusions with postural change. In small volume effusions, the fluid was truly posterior at and below the atrioventricular groove. With moderate-sized effusions a more uniform distribution of the fluid was found, and with large effusions more fluid was visualized apically, posteromedially, laterally and anteriorly. Upright redistribution of the fluid was seen with moderate to large nonloculated effusions. Assumption of a uniform distribution of pericardial effusion used for M mode quantification is most valid for moderate effusions and less valid for small and large effusions. Imaging was performed in two additional patients with cardiac tamponade to assess qualitative changes in short axis ventricular volumes with respiration. The introduction of a pericardiocentesis needle was visualized. Clinical implications are discussed.