Background  At present, the incidence of acute myocardial infarction is increasing rapidly in China, while the prevention and treatment of heart failure after myocardial infarction is not optimistic.

  Objective   To investigate the dynamic changes of serum exosomal microRNA (microRNA, miR)-122 and miR-194 in the early stage of myocardial infarction and provide reference for the early diagnosis of heart failure after myocardial infarction.

  Methods   From January 2018 to June 2020, 96 patients with acute myocardial infarction admitted to Beijing Daxing District Hospital of Integrated Chinese and Western Medicine were selected. All patients received percutaneous coronary intervention (PCI) treatment, and based on whether heart failure occurred after AMI, they were divided into heart failure after AMI group (n=35) and non-heart failure group (n=61). Reverse transcription polymerase chain reaction (RT-PCR) was used to detect and compare the levels of serum miR-122, miR-194 and Precursor (N-terminal pro-brain natriuretic peptide, NT-proBNP) concentration in the venous blood of the two groups at 1 h, 12 h, 20 h, 24 h and 48 h after onset, and Pearson correlation was used to analyze the correlation between serum miR-122, miR-194 levels and NT-proBNP concentration. The receiver operating characteristic curve (ROC) was used to analyze the diagnostic value of miR-122 and miR-194 expression levels at each time point in patients with heart failure.

  Results   Overall analysis (two factor repeated measurement analysis of variance) revealed that there were statistically significant differences in indexes, time and interaction between the groups (P<0.05). The venous blood serum NT-proBNP concentration and miR-194 level of the two groups increased at 1 h, 12 h, 20 h, 24 h and 48 h after the onset, and then decreased, and peaked at 24 h after onset; The level of miR-122 showed a trend of first decrease and then increase, and the relative expression level was the lowest at 24 h after the onset. Except for the time point of 1 h after operation, the serum NT-proBNP concentration and miR-194 level in the heart failure after AMI group were higher than that of the non-heart failure at each time point, while the miR-122 level was lower than that of the non-heart failure group (P<0.05). Pearson correlation analysis showed that serum miR-122 expression level was negatively correlated with NT-proBNP (r=-0.667, P=0.012), and serum miR-194 expression level was positively correlated with NT-proBNP (r=0.854, P=0.004). The results of ROC analysis showed that, except for the time point of 1 h after operation, the miR-122 and miR-194 levels in patients with AMI showed a better diagnostic value for heart failure at other time points, with the highest diagnostic value at 12 h, and the area under the ROC curve was 0.941 (95% CI: 0.901 - 0.965) and 0.867 (95% CI: 0.829 - 0.906), respectively.

  Conclusion   The sera level of miR-122 show a single-peak trend of first decrease and then increase in patients with AMI, while the trend of miR-194 is opposite, and the expression levels of them are significantly correlated with the concentration of NT-proBNP. There are differences in the diagnostic value of miR-122 and miR-194 levels at different time points in heart failure, which is expected to become a potential new serum biomarker for assisted diagnosis of heart failure.