Diagnostic value of endomyocardial biopsy for endomyocardial fibrosis

Endomyocardial fibrosis (EMF) is a restrictive cardiomyopathy of unknown etiology. It is mainly prevalent in the tropical and subtropical countries. The aim of this study was to evaluate the diagnostic value of endomyocardial biopsy (EMB) for EMF, and detect the relationship between Coxsackie virus B3 (CVB3) and EMF in the Chinese patients. The right ventricular EMB was performed in 18 patients who had been diagnosed as EMF by angiocardiography, echocardiography and/or magnetic resonance imaging. CVB3 in eight patients’ endomyocardial samples was detected with CVB3 cDNA probe by in situ hybridization method. The successful rate of EMB was 83.3% (15/18 cases) in this study. The major histopathological findings of EMB were endocardial thickened in 11 cases (73.3%), endocardial collagen fibration in 14 cases (93.3%), endocardial hyalinization in 7 cases (46.7%), small vessel growing in the endocardial deep layer in 10 cases (66.7%), wispy fibrotic tissues extend into subendocardial myocardium in 7 cases (46.7%), myocardial interstitial fibrosis in 7 cases (46.7%), myocardial hypertrophy, degeneration or amyotrophy in 9 cases (60.0%), and inflammatory cell (lymphocytes and macrophages) infiltration in 7 cases (46.7%). The histopathological findings were found to be diagnostic in 12 patients (80.0%). No positive hybridization signal was detected in all of the eight patients. The results of the present study suggest that EMB is a quite useful diagnostic technique for EMF, but the pathogenesis of EMF may be not related with CVB3 direct infection.