Objective: To investigate the expression and mechanism of plasma microRNA-21 (miR-21) in patients with ischemic cardiomyopathy (ICM). Methods: 54 patients with ICM who were treated in our hospital from February 20 10 to March 2016 were selected as the observation group, 58 healthy subjects were selected as the control group at the same time.The expression level of miR-21 of the two groups were measured by real-time quantitative PCR (qRT-PCR). The differences of total cholesterol (TC),three glycerol (TG), left ventricular ejection fraction (LVEF), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), left ven- tricular end diastolic volume (LVEDV), N terminal B type brain natriuretic peptide (NT-proBNP) of the two groups were compared. The correlation between plasma miR-21 level and the above clinical parameters was analyzed, and the value of miR-21 in ICM diagnosis and treatment was evaluated. Results: The levels of LDL-C, HDL-C and LVEF in the observation group were lower than those in the control group, the difference was statistically significant (P〈0.05). The plasma levels of miR-21, TG, NT-proBNP and LVEDV were higher than those of the control group,the difference was statistically significant (P〈0.05). Pearson correlation analysis showed tb.at the plasma level ofmiR-21 in the observation group were positively correlated with NT-proBNP and LVEDV (P〈0.05). The plasma level ofmiR-21 were not correlated with LVEF, LDL-C, HDL-C, TG and TC (P〉0.05). Conclusion: The expression of plasma miR-21 is increased significantly in patients with ICM, and the expression is positively correlated with NT-proBNP and LVEDV. It plays a role in ventricular remodeling oflCM patients, which can be used as a new target for the diagnosis and treatment of ICM and a new biomarker for risk assessment. [ABSTRACT FROM AUTHOR]