Serum magnesium predicts new-onset atrial fibrillation in ST-segment elevation myocardial infarction patients after...

New-onset atrial fibrillation (NOAF) following ST-segment elevation myocardial infarction (STEMI) is associated with increased morbidity and mortality. Magnesium (Mg), a key regulator of cardiac electrophysiology, has been implicated in arrhythmogenesis; however, its predictive value for NOAF in STEMI remains unclear.

This retrospective study included 2426 consecutive STEMI patients who underwent primary percutaneous coronary intervention (p-PCI). Patients were categorized based on the occurrence of NOAF during hospitalization. Clinical, laboratory, and procedural data were compared between groups. Logistic regression and receiver operating characteristic (ROC) analyses were performed to identify independent predictors and determine the optimal Mg threshold for NOAF.

NOAF occurred in 109 (4.5%) patients. Patients with NOAF had significantly lower serum Mg levels (median: 1.70 vs. 2.10 mg/dl; P < 0.001) and a higher proportion of Killip Class greater than 1. ROC analysis identified a Mg threshold of less than 1.88 mg/dl for predicting NOAF (area under the curve: 0.757; sensitivity: 71.5%, specificity: 78.1%). Low Mg was an independent predictor of NOAF in multivariable logistic regression analysis (odd ratio: 2.45; 95% confidence interval: 1.60-4.14; P = 0.007).

Admission serum Mg level is an independent predictor of NOAF in STEMI patients undergoing p-PCI. Mg assessment may support risk stratification and guide preventive strategies.