Pericardial effusion diagnosed by echocardiography. Clinical and electrocardiographic findings in 171 patients.

Clinical and electrocardiographic findings in 171 patients with pericardial effusion diagnosed by echocardiographic studies were reviewed. In 70 patients the effusion was unsuspected. There were 87 small, 50 moderate, and 31 large effusions. Cardiac tamponade was present in three patients. Congestive heart failure was the most common cause of pericardial effusion and occurred in 37 patients. Other frequently noted conditions included cardiac disease without congestive heart failure, neoplasms, acute nonspecific pericarditis, renal failure, and acute myocardial infarction. A pericardial friction rub was present in 23 patients, two-thirds of whom had moderate or large effusions. Atrial arrhythmias were common. Low voltage occurred in 31 of 136 patients and was more common with large effusions. The ability to distinguish between a small effusion and the quantity of pericardial fluid present normally is a problem requiring further clarification.