Abstract: Objective To explore the protective effect of microRNA-499 (miR-499) against myocardial apoptosis in non-ischemic heart failure. Methods Adeno-associated viral vector of rno-miR-499 and pacing-induced heart failure rat model was established, and then rats were infected by recombinant adeno-associated virus. The expression level of miR-499 was detected by qPT-PCR, protein concentrations of Pscd4 and PACS2 were determined using western blot assay. Apoptosis was detected via immunohistochemistry and TUNEL assay. Results Adeno-associated viral miR-499 was successfully transfected, and it led to specific overexpression of miR-499. Compared with the sham group, the LVEF (81.8%±2.4% vs 64.3%±2.2%) and LVFS (44.7%±2.4% vs 29.1%±0.9%) of the pacing+NC group decreased significantly (P< 0.05, respectively), while the autonomic heart rate and LVEDP increased significantly. Compared with the pacing+NC group, the autonomic heart rate (441.6±22)/min vs (368.4±27)/min and LVEDP (34.8±11.4) mmHg vs (19.4±10.3) mmHg of the pacing group decreased significantly (all P< 0.05). We found that enhancing the expression of miR-499 could significantly inhibit the expression of PDCD4 and PACS2 in pacing-induced heart failure rats. Furthermore, cell apoptosis increased by pacing, but attenuated by up-regulated miR-499. Conclusion MiR-499 may inhibit apoptosis in pacing-induced heart failure via PDCD4 and PACS2 pathway.