Atrial Septal Defect Management Status and Long‐Term Outcomes After Atrial Fibrillation Ablation: A Real‐World Cohort Study

BACKGROUND: As more adults with atrial septal defect (ASD) survive into older age and undergo atrial fibrillation (AF) ablation, evidence to guide post-ablation risk stratification remains limited. OBJECTIVE: To evaluate long-term outcomes after the first AF ablation across ASD management states compared with an intact interatrial septum. METHODS: This real-world cohort study included 27 675 patients undergoing their first AF ablation, classified by interatrial septal status as intact septum (n = 27 134), unrepaired ASD (n = 232), percutaneous closure (n = 119), or surgical repair (n = 190). Three pairwise comparisons with an intact septum were constructed. Propensity score overlap weighting was used to balance baseline characteristics, and Cox proportional hazards models were used to assess outcomes. The primary outcome was atrial arrhythmia recurrence after the 3-month blanking period; the secondary outcome was a composite cardiovascular outcome. RESULTS: Compared with an intact septum, unrepaired ASD was associated with a higher recurrence risk (hazard ratio [HR], 1.27; 95% CI, 1.07-1.51; p = 0.006), with excess risk mainly observed between 3 months and 1 year after ablation. Surgical repair was also associated with higher recurrence risk (HR, 1.21; 95% CI, 1.01-1.46; p = 0.038), with differences emerging beyond 1 year. Percutaneous closure was not associated with increased recurrence risk (HR, 1.07; 95% CI, 0.83-1.38; p = 0.589). Composite cardiovascular outcomes did not differ significantly across groups. CONCLUSIONS: ASD management status identified distinct temporal patterns of atrial arrhythmia recurrence after AF ablation, suggesting that ASD should not be treated as a single binary condition in post-ablation risk assessment.