Myocardial and endocardial involvement in tuberculous constrictive pericarditis: difficulty in biopsy distinction from endomyocardial fibrosis as a cause of restrictive heart disease.

Differentiation of constrictive pericarditis and endomyocardial fibrosis by the available diagnostic methods is difficult at present. With this in mind, we compared autopsy data in heart specimens from 8 patients of constrictive pericarditis of tuberculous origin and 6 patients with tropical endomyocardial fibrosis. Post-mortem endomyocardial biopsies were also performed from both the ventricles. Pericardial thickening and adhesions were present in all cases of constrictive pericarditis and in none of those with endomyocardial fibrosis. Interestingly, significant endocardial thickening was seen in four, and myonecrosis, lymphohistiocytic cellular infiltration and myofibrosis were observed in seven of the eight cases of constrictive pericarditis. This suggests that the tubercular insult to heart may result in involvement of all three layers with varying severity. The endomyocardial biopsy specimens from the affected areas revealed similar histopathological changes of endocardial thickening and focal myofibrosis with cellular infiltrates in patients with both constrictive pericarditis and endomyocardial fibrosis, making distinction of the two difficult. The hallmark of differentiation between these two clinical entities appears to be a diligent attempt at identification of the thickened pericardium.