The Association of Electrical Alternans with Pericardial Effusion

¹ Cardiopulmonart Laboratory, Department of Internal Medicine, the University of Texas Southwestern Medical School

Electrical alternans of the QRS complex may be of three types: those associated with paroxysmal tachycardia, those exhibiting ventricular conduction defects and those with normal QRS showing alternation in voltage with normal moderately rapid heart rate. The latter type is frequently associated with pericardial effusion, and total electrical alternans is practically pathogenomonic of it. The pericardial effusion is almost always an exudate and in four of our six cases, the disease was due to malignancy infiltrating the pericardium.

The diagnostic value of total alternans is obvious, but the detection of the P wave alternation may be difficult. Increased standardization of the recorder and postural changes are hoped to bring out suspected cases.