Early diastolic sound of constrictive pericarditis.

In two patients with constrictive pericarditis an absent or faint early diastolic sound became prominent with squatting, phenylephrine infusion or injection of contrast medium and was obliterated by nitroglycerin. The lability of the sound allowed correlations to be made with acute changes in the right ventricular pressure curve. By eliciting an otherwise inaudible early diastolic sound, squatting may be a useful bedside maneuver in the diagnosis of constrictive pericarditis.