Characteristics and significance of gut microbiota alterations in patients with acute myocardial infarction and their association with the occurrence of heart failure

Objective In the context of real-world clinical practice, this study aimed to systematically investigate the characteristics of gut microecological alterations in patients with acute myocardial infarction (AMI), elucidate their potential clinical significance, and further analyze the association between gut microbiota imbalance and the short-term occurrence of heart failure (HF) in AMI patients, as well as the related influencing factors. Methods This study adopted a single-center retrospective case–control design. A total of 143 AMI patients who received standardized diagnosis and treatment in our hospital between April 2023 and June 2025 were enrolled as the disease group, while 120 healthy volunteers undergoing physical examination during the same period were selected as the control group. Selected cultivable gut microbial groups in both groups were quantitatively assessed using culture-based methods. All AMI patients were followed up for 30 days and were divided into group A (HF occurred, n=44) and group B (HF did not occur, n=99) according to whether HF events occurred during the follow-up period. Differences in gut microbiota composition and cardiac function–related indicators, including N-terminal pro–B-type natriuretic peptide (NT-proBNP) and left ventricular ejection fraction (LVEF), were compared between the two groups. Correlation analysis and multivariable logistic regression models were applied to explore the relationships between the selected gut microbial indicators and cardiac function indicators and to identify factors independently associated with HF occurrence in AMI patients. Results Compared with the control group, the disease group showed a significant increase in the number of conditional pathogenic bacteria and aerobic bacteria in the gut, with markedly higher levels of Enterobacter, Enterococcus, Clostridium, fungi, and total aerobic bacteria (P<0.05). In contrast, beneficial bacteria were significantly reduced, as evidenced by decreased levels of Bacteroides, Bifidobacterium, Lactobacillus, and total anaerobic bacteria (P<0.05). Further subgroup analysis revealed that, compared with group B, group A had significantly lower abundances of beneficial bacteria (Bacteroides, Bifidobacterium, Lactobacillus, and total anaerobic bacteria), while the numbers of Enterobacter, Enterococcus, and total aerobic bacteria were markedly increased (P<0.05). Meanwhile, LVEF levels were significantly lower and NT-proBNP levels were significantly higher in group A than in group B (P<0.05). Correlation analysis showed that the numbers of Enterobacter, Enterococcus, and total aerobic bacteria were significantly positively correlated with NT-proBNP levels and negatively correlated with LVEF (P<0.05). Conversely, the numbers of Bacteroides, Bifidobacterium, Lactobacillus, and total anaerobic bacteria were negatively correlated with NT-proBNP and positively correlated with LVEF (P<0.05). Multivariate regression analysis further confirmed that Bacteroides, Bifidobacterium, Lactobacillus, total anaerobic bacteria, LVEF, Enterobacter, Enterococcus, total aerobic bacteria, and NT-proBNP were all independent influencing factors for the occurrence of HF in AMI patients. Conclusion AMI patients exhibit a certain degree of alteration in gut microbiota structure, mainly characterized by a reduction in the abundance of some beneficial bacteria and a relative increase in conditional pathogenic bacteria. These gut microecological changes are associated with cardiac function indicators and the short-term occurrence of HF, suggesting that gut microbiota imbalance may have a potential link with adverse cardiac functional outcomes after AMI. However, given that this study was a single-center retrospective investigation, the findings still require further validation in larger, multicenter, and prospective studies.