Four weeks after Exo treatment, venous blood samples were collected for ELISA to detect myocardial injury related indicators (BNP, CK-MB, cTnI and TNF-a), qRT-PCR and Western Blot to detect the expression level of key gene Smad3, HE staining and Masson staining to evaluate the degree of myocardial fibrosis. The gene discussed is SMAD3; the disease is Myocardial fibrosis.