Prognostic effect of restoring sinus rhythm in patients with new-onset atrial fibrillation during acute coronary syndrome

Background: New-onset atrial fibrillation (NOAF) in acute coronary syndrome (ACS) may be associated with a poor prognosis. However, whether restoring sinus rhythm (SR) at discharge in patients with ACS improves outcomes remains unknown. Methods: A total of 552 patients with ACS at an emergency department during 2011-2016 were enrolled. According to documented electrocardiography at admission and medical records, the patients were classified into without atrial fibrillation (WAF), NOAF, and prior atrial fibrillation (PAF) groups. Major adverse events (MAEs) were defined as cardiac death, recurrentmyocardial infarction, heart failure requiring hospitalization, target lesion revascularization, and stroke. The mean follow-up period of MAEs was 25 ± 15 months. Results: Compared with the NOAF and PAF groups, theWAF group was younger and had a significantly lower heart rate, prior stroke rate, CHA2DS2-VASc score, and lower Global Registry of Acute Coronary Events (GRACE) score in the emergency department (p < 0.001). The patients in the NOAF group had the highest incidence of MAEs (p < 0.001) during follow-up, and those whose SR was restored at discharge had a lower MAE rate than those with AF at discharge (p = 0.001). Inmultivariable analysis, priormyocardial infarction, GRACE score, use of beta-blockers, and restoring SR at discharge were independent predictors of MAEs in the NOAF group. Conclusions: The patients with ACS who presented with NOAF had worse outcomes than those with PAF or WAF. The patients with NOAF whose rhythm was restored to SR at discharge were associated with better outcomes than those with AF at discharge.