Microvascular study of hearts with endomyocardial fibrosis.

The vascularity of ii hearts with endomyocardialfibrosis, which were part of a larger series of I47 heartsfrom patients dying at the Mulago Hospital, Kampala, Uganda, have been studied by injection, microradiographic, and histological techniques. A complete range of pathological types of endomyocardial fibrotic hearts were studied. Every heart showed some pericarditis and small scars scattered within the myocardium, while three hearts contained smallfoci of active myocarditis, but without eosinophil infiltration. No constant relation was seen between the distribution of endocardial and myocardial damage, but in general the more extensive the endocardial damage the more extensive the myocardial damage, particularly in the subendocardial zone. Endocardial thrombus became organized by numerous small vessels extending outfrom the subendocardial zone while the resulting fibrous tissue was relatively avascular. The valves were not primarily diseased but were secondarily involved by encroaching organizing thrombus. The findings show that a small vessel pathology is unlikely and that endomyocardial fibrosis should be considered a pancarditis. It is suggested that more attention should be directed at establishing whether a toxic or infective agent acting directly on the endocardium and myocardium is of importance and whether there is an abnormal individual response.