Different associations between left atrial size and 2.5-year clinical outcomes in patients with anterior versus non-anterior wall ST-elevation myocardial infarction

OBJECTIVE: To investigate associations between left atrial diameter (LAD) and long-term outcomes in patients with anterior or non-anterior wall ST-elevation myocardial infarction (STEMI). METHODS: Patients with STEMI were included in this secondary analysis of data from a prospective cohort study in which the primary outcome was major adverse cardiovascular event (MACE) occurrence during a 2.5-year follow-up. A LAD cut-off value was obtained through receiver operating characteristic curve analysis. Kaplan-Meier curve and Cox regression analyses were applied. Subgroup Cox regression analysis was also performed, with patients stratified based on left ventricular diastolic diameter (LVEDD, > 55 mm and ≤55 mm). The relationship between LAD and outcomes in patients with anterior or non-anterior wall STEMI was explored using restricted cubic spline functions. RESULTS: Out of 464 patients, adjusted Cox regression showed that dichotomous (>40 mm) LAD was significantly associated with MACE (hazard ratio 2.978, 95% confidence interval 1.763, 5.030) in patients with anterior wall but not non-anterior wall STEMI. The association was not different between normal and enlarged LVEDD groups. CONCLUSIONS: A left atrium > 40 mm may indicate higher risk of MACE in patients with anterior wall STEMI, even in patients with normal left ventricular structure. This relationship was not observed in patients with non-anterior wall STEMI.