[Clinical significance of immunohistochemistry and ultrastructural change of myocardium in viral myocarditis].

Endomyocardial biopsy (EMB) specimens from 56 patients with suspected viral myocarditis (VMT) were studied. With microscopical study of the EMB specimens stained with HE, 14 of the 56 cases were diagnosed as myocarditis (25%) and 24 as non-myocarditis (43%). But immunohistochemistry stain showed that the contents of myosin, actin and myoglobin reduced in 51 patients (91%). Ten of 56 specimens were observed under electron microscope (EM). EM examination revealed focal or diffuse lysis of myofibrils in 10 patients. The results showed that: (1) The myofibrils in VMT showed severe damage. (2) Immunohistochemistry and EM examination can be used as a supplement to the Dallas diagnosis standard in order to improve accuracy of EMB in diagnosing VMT.