The pathogenesis of endomyocardial fibrosis: the question of 5-hydroxytryptamine.

Thirty Nigerians with established endomyocardial fibrosis were studied. Basal serum 5-hydroxytryptamine levels were estimated on three different occasions at one-monthly intervals. Twentyfour hours before each estimation, dietary staples containing 5-hydroxytryptamine were excluded from the diet. Subsequently the patients were fed on a plantain diet and serum levels of 5-hydroxytryptamine were estimated at one- and three-hour intervals after plantain ingestion. 5-hydroxytryptamine was assayed on the fundal strip of rat's stomach. These values were compared with those obtained in an earlier study on healthy Nigerians. It was observed that, as in healthy Nigerians, no significant increase in serum 5-hydroxytryptamine levels occurred in these patients after plantain ingestion. The difference between endomyocardial fibrosis and carcinoid heart disease is underlined and it is emphasized that no correlation exists between the incidence of endomyocardial fibrosis and the high content of 5-hydroxytryptamine in the local dietary staples.