Abstract: objective In order to improve the accuracy and reliability in sudden cardiac death, the pathogenesis and relationship between the viral myocarditis and dilated cardiomyopathy were investigated. Methods Improved immunohistochemical technique was adopted to detect the expression of the dystrophin in myocardium from 25 viral myocarditis, 28 dilated cardiomyopathy and 17 control cases including normal, coronary atherosclerotic heart disease and hypertension heart disease as control. Results The positive rate of dystrophin protein expression in control group was 100%, that in viral myocarditis was 88%, and that in dilated cardiomyopathy was 57%, There were significant differences among three groups (P<0.05), and the correlation between viral myocarditis and dilated cardiomyopathy group(r= -0.526)were also found. Conclusion The myocardial cytoskeletal protein is disrupted in viral myocarditis and dilated cardiomyopathy ,and the dystrophin protein may be involved in the pathogenesis of viral myocarditis and dilated cardiomyopathy. The viral infect and impair heart functions by cleaving host dystrophin proteins may ultimately contributes to the viral myocarditis to the converting from dilated cardiomyopathy.

Key words: sudden death, dystrophin protein, viral myocarditis, dilated cardiomyopathy, immunohistochemistry