Physiological features of pericardial constriction in the absence of pericardial disease.

To sustain a clinical diagnosis of constriction it is classically held that the fibrous pericardium must be thickened and adherent to the surface of the heart. A case is presented in which leukaemic infiltration of the fat overlying the myocardium resulted in the physiological features of constriction, although all layers of the pericardium itself were normal. Constriction is thus a physiological diagnosis; it may develop in the absence of the classical anatomical findings.