Abstract: Objective To study the pathogenesis of viral myocarditis (VMC) and dilated cardiomyopathy (DCM) and their relationship. Methods Sixty samples including 20 VMC, 20 DCM and 20 controls were collected. The expression of Fas protein in myocardium of each group was detected by modified immunohistochemistry with unequivocal brown staining in the myocardial membrane scored as positive, and the results of positive reaction were analyzed by Ridit test. Results Fas protein expression increased obviously in VMC and DCM groups as compared with that of the control group. The difference of positive results between each group analyzed by Ridit test was statistically significant (P<0.005). Statistically significant differences were found between VMC and control groups as well as between DCM and control groups (P<0.05), but not between VMC and DCM groups(P>0.05) by multiple comparison Ridit test. Conclusion The expression of Fas protein is significantly higher in the VMC and DCM groups than in that of the control group. These results suggest that both the VMC and DCM may share a similar pathogenesis, which most likely involves cell apoptosis.

Key words: forensic pathology, cardiomyopathy, dilated, viral myocarditis, Fas protein, apoptosis