AIMS
Left ventricle ejection fraction (LVEF) recovery after st-segment elevation myocardial infarction (STEMI) is variable and difficult to predict in routine practice. While door-to-balloon time remains a key quality metric, the relevance of prolonged symptom duration prior to presentation, angiographic disease burden, and early post-percutaneous coronary intervention (PCI) echocardiographic findings for long-term LVEF recovery is overlooked. We sought to evaluate these underexplored variables as predictors of persistent LVEF dysfunction following a first STEMI treated with primary PCI.

METHODS AND RESULTS
We performed a retrospective analysis of 131 consecutive adults presenting with index STEMI to a community hospital between January 2015 and July 2024. Patients were included if they underwent primary PCI, had reduced LVEF on the initial post-PCI echocardiogram, and had follow-up echocardiographic assessment after hospital discharge. To ensure the impact of myocardial injury arising from the index STEMI, patients with prior coronary artery disease, previous myocardial infarction or PCI, known left ventricle dysfunction, rescue PCI, or malignancy treated with chemotherapy/radiation were excluded. Detailed clinical presentation variables, including chest pain duration prior to hospital presentation, electrocardiographic findings, peak troponin I, early echocardiographic parameters, angiographic characteristics, and in-hospital recovery variables were analyzed. The primary outcome was persistent LVEF ≤40% on follow-up echocardiography. Multivariable logistic regression was used to identify independent predictors of LVEF non-recovery.
At follow-up, 57% of patients demonstrated persistent LVEF ≤40%. Chest pain duration >24 hours prior to presentation was independently associated with persistent LVEF dysfunction (p<0.001). Higher syntax score and troponin I were each significantly associated with increased odds of non-recovery (p=0.01 and p=0.002, respectively). Lower initial post-PCI LVEF also affected recovery: patients with initial LVEF ≥26% had significantly lower odds of persistent dysfunction compared with those with LVEF <26%. Door-to-balloon time and other clinically important variables such as culprit vessel, st-segment distribution on electrocardiogram, and Thrombolysis In Myocardial Infarction (TIMI) flow post-intervention were not independently associated with LVEF recovery.

CONCLUSIONS
In patients presenting with a first STEMI undergoing primary PCI, prolonged symptom duration prior to hospital presentation is strongly associated with persistent left ventricle dysfunction, independent of door-to-balloon time. Angiographic disease complexity, troponin I levels, and early post-PCI LVEF by echocardiogram further inform the likelihood of LVEF recovery. This study reinforces the importance of early intervention in STEMI management and suggests that a comprehensive understanding of angiographic and clinical factors may help to better predict and manage long-term cardiac outcomes