Constrictive pericarditis represents a pericardial pathology — a disease of the pericardium external to the myocardium, in which a thickened, fibrotic, or calcified pericardium restricts diastolic filling. In contrast, restrictive cardiomyopathy is a myocardial disorder, where the ventricular walls themselves become stiff and noncompliant, limiting diastolic filling despite a normal pericardium. CP: @Septal bounce, respiratory variation in Doppler inflows, preserved e′ at medial annulus, thicken