Martins, Ana MargaridaLima da Silva, Gustavo2025-07-282025-07-282025Rev Port Cardiol. 2025 Jul;44(7):413-4150870-2551http://hdl.handle.net/10400.5/102460© 2025 Published by Elsevier España, S.L.U. on behalf of Sociedade Portuguesa de Cardiologia.Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and has been observed in up to 21% of hospitalized patients experiencing acute myocardial infarction (AMI). Potential triggers of AF in this context include hemodynamic instability resulting from left ventricular dysfunction, pericardial inflammation, atrial ischemia or infarction, metabolic disturbances, and elevated levels of endogenous or exogenous catecholamines. Multiple studies have investigated the clinical profiles of patients who develop AF during AMI. One of the largest datasets comes from the Cooperative Cardiovascular Project,4 where multivariate analysis identified advanced heart failure (Killip class IV) as the strongest predictor of AF development; other significant predictors included elevated admission heart rate, which may reflect left ventricular dysfunction and hemodynamic compromise, and advanced age.engjournal article10.1016/j.repc.2025.06.0012174-2030