The impact of new-onset atrial fibrillation in the setting of acute coronary syndrome

Approximately 10 % of patients who have suffered from myocardial infarction develop new-onset atrial fibrillation (AF). Coronary artery disease implicating atrial branches has been associated with AF. The following variables have been associated with new-onset AF in the setting of acute coronary syndrome: older age, history of hypertension, history of angina, history of stroke, chronic renal failure, body mass index, no statin use, worse nutritional status, worse Killip class, admission heart rate ≥ 85 bpm, complete atrioventricular block, Glasgow prognostic score, Syntax score, C₂HEST score > 3, PRECISE-DAPT score ≥ 25, left ventricular ejection fraction ≤40 %, increased left atrial diameter, E/E′ ratio > 12, epicardial fat tissue thickness, and thrombolysis in myocardial infarction flow < 3. Regarding laboratory variables, elevated D-dimer levels, C-reactive protein levels, N-terminal pro-B-type natriuretic peptide, creatine kinase-MB, high-sensitivity troponin T at baseline, midregional pro–atrial natriuretic peptide, and cholesterol levels have been proposed as potential predictors of AF in this setting. Regarding the impact of new-onset AF on clinical outcomes, it has been associated with an increased risk of stroke, higher mortality rates, heart failure, cardiogenic shock, higher odds of ventricular arrhythmias and major adverse cardiac events. New-onset AF is an indicator of worse in-hospital prognosis compared to patients with a previous history of AF. New-onset AF, as well as previous AF, were strong predictors of ischemic stroke, and therefore, patients with new-onset AF should be anticoagulated according to the CHA₂DS₂-VASc score. Cardioversion to sinus rhythm, if possible, is advised before the discharge as it may be related to better outcomes.