BackgroundThere are limited data about the incidence and outcomes of atrial fibrillation (AF) in adults with coarctation of aorta (COA). The purpose of this study was to determine the incidence, correlates, and prognostic implications of new-onset AF in adults with repaired COA. MethodsA retrospective cohort study of adults with repaired COA without a prior history of atrial arrhythmias was performed. We reviewed rhythm data (electrocardiogram, Holter, and rhythm strip) obtained from baseline to the last clinical encounter. The correlates of AF and the relationship between AF and cardiovascular adverse events (heart failure hospitalization and/or all-cause mortality) were assessed using Cox regression. ResultsOf 782 patients (aged 32 [interquartile range: 21-43] years; 462 [59%] men), 42 (5.4%) developed new-onset AF. The incidence of new-onset AF was 9 per 1000 patient-years (0.9% per year), and the median age at onset of AF was 36 (interquartile range: 24-49) years. The correlates of new-onset AF were older age, hypertension, left atrial dysfunction, and left ventricular hypertrophy. Of 782 patients, 92 (12%) had cardiovascular adverse events. On multivariable analysis, new-onset AF was associated with cardiovascular adverse events (hazard ratio: 1.09, 95% confidence interval: 1.03-1.15), after adjustment for age, hypertension, and right and left ventricular structure and function. ConclusionsPatients with COA were at risk for developing AF at a relatively young age (median age: 36 years), and AF was associated with cardiovascular adverse outcomes. There is a need to target the modifiable risk factors for AF to reduce the adverse outcomes associated with AF.