CircRNA serves a crucial role in the development of heart failure (HF). Nevertheless, the regulatory mechanisms of circ_0062389 in HF are unknown. This study aims to examine the effect and mechanism of circ_0062389 on cardiomyocyte apoptosis in HF rats and H9C2 cells. Rats were divided into 5 groups (n=8/group): the Control group, Sham group, HF group, HF+si-NC group, and HF+si-circRNA group. The echocardiography was used to examine the cardiac function, including LVIDd, LVIDs, IVSd, and IVSs. The apoptosis of myocardial tissue was detected through TUNEL method. H9C2 cells were randomly assigned into Control group (untransfected H9C2 cells), H/R group (untransfected H/R H9C2 cells), H/R +si-NC group (transfected si-NC) and H/R + si-circRNA group (transfect si-circ_0062389). Cell apoptosis was assessed through flow cytometry. The expression of circ_0062389 in myocardial tissues of HF rats was significantly higher than that of Control group and Sham group. Silencing circ_0062389 significantly reduced the levels of LVIDd, LVIDs, IVSd, and IVSs. Additionally, silencing circ_0062389 could significantly reduce the apoptosis rate of rat cardiomyocytes. Besides, silencing circ_0062389 significantly reduced the expression of TGF-β1 and Smad3 protein. Silencing circ_0062389 could alleviate cardiomyocyte apoptosis in HF rats via modulating TGF-β1/Smad3 signaling pathway, which might be a promising target for the treatment of HF.Copyright © 2020 Elsevier B.V. All rights reserved.