To the Editor.
—In the September issue of the Archives, Leehey et al1 came to the conclusion that pericardial effusions (when found in patients undergoing dialysis) should be drained promptly in the absence of cardiovascular compromise. They arrived at this conclusion with an uncontrolled observation, noting, in their experience during a seven-year period, four deaths apparently related to the presence of pericardial effusion. The authors did not demonstrate cause and effect of the pericardial effusion in sudden deaths in these four cases. In one, the death occurred after drainage of the pericardial effusion. There was no control group of patients who underwent early pericardial drainage with which we can compare these results. No information was given with regard to dialysis or such details as the presence or absence of hyperkalemia, volume control, or other potential causes of acute cardiopulmonary death.One major concern is the determination of what is