Augmentation of Electrical Alternans with Lowering of the Heart Rate in Massive Pericardial Effusion

Abstract

A patient with massive pericardial effusion and electrical alternans was studied. Intravenous administration of 8 mg practolol produced a decrease in heart rate from 120 to 87 beats/min, with increase of the alternans. The postulation that tachycardia is necessary for the appearance of electrical alternans in cardiac tamponade cannot be supported from this finding.