Viral myocarditis and myocardial fibrosis

Myocardial fibrosis is caused by the excessive accumulation of collagen. It can be found in all stages of viral myocarditis,especially in the recovery and chronic stage. The myocardial fibrosis is regulated by many factors including direct viral tissue damage and indirect damage caused by transforming growth factor β1(TGF-β1),renin-angiotensin-aldosterone system, nitric oxide/endothelin,and mammalian target of rapamycin(mTOR). There is a lack of specificity in the clinical manifestations of myocardial fibrosis. The anti-fibrosis therapy is necessary only in the chronic stage of viral myocarditis.