The Function of the Heart in Endomyocardial Fibrosis of the Right Ventricle.

Endomyocardial fibrosis is a common heart disease among the indigenous peoples of many of the tropical African countries. The morbid anatomical findings have been described in detail by Davies and Ball (1955) so that only the fundamental features require comment here. The initial lesion seems to be in the endocardium at the apex of either or both ventricles. Thence the fibrotic process spreads up the ventricular wall and the cavity ofthe ventricle is slowly obliterated from below. At the same time the papillary muscles become anchored in the bed of fibrous tissue: later the chorde tendinee and finally even the cusps of the atrio-ventricular valves are enmeshed as the fibrosis progresses, so that valvular incompetence results (Fig. 1). The fibrotic endocardium becomes rigid so that diastolic filling of the ventricle is restricted and the deformed atrioventricular valve allows blood to regurgitate. The inevitable changes in the function of the heart are more dramatic, and are easier to study, on the low pressure right side of the heart. The clinical features of established right ventricular endomyocardial fibrosis have been described elsewhere by one of us (Abrahams, 1962), when some preliminary observations on cardiac output both at rest and after effort were reported. We report here the results of more detailed hemodynamic studies of these deformed hearts and we have also compared our findings with published reports of patients with impaired diastolic filling of the ventricle from other causes.