Macroscopic Findings.
The hearts in all group 1 and 2 patients showed increased size and weight, hypertrophy, and dilation of the left and right atria and ventricles. The myocardium appeared pale and flabby, and endocardium showed punctuate petechial hemorrhages (Figure 4A1). Some patients in group 1 had pathological changes that were related to the patient’s age. These included myocardial ischemic or inflammatory changes, hypertensive changes of the left ventricular cavity, and valvular calcification of the mitral annulus and aortic valve (Figure 4A2).
Figure 4.  Histological changes in heart. A1, Hearts were increased in size and weight. The myocardium appeared pale and flabby. Endocardium showed punctuate petechial hemorrhages. A2, Age-related disease of the heart was represented by volume changes of the left ventricular cavity and exacerbated by systemic hypertension with valve changes including calcification of the mitral annulus and aortic valve. A3 and A4, Heart tissue shows myocytes hypertrophy, and variable degrees of interstitial and vascular fibrosis with mononuclear cells infiltrating adventitia. B1, Active myocarditis was characterized by mononuclear, predominantly lymphocytic infiltrate, associated with focal myocytes necrosis (B2). B3, Fibrinous, hemorrhagic areas with myofibers disarray were present. B4, Pericarditis with lymphocytic infiltration and increase in fibrous tissue was seen in all patients. Abbreviation: H&E, haematoxylin and eosin. Scale bars: A3 and B4, 21 µm; A4–B2,7 µm; B3, 14 µm.