Timing and technique matter: closure of secundum atrial septal defect and risk of incident and recurrent arrhythmia

Background Atrial septal defect (ASD) is a simple defect but carries considerable morbidity, especially arrhythmias. Yet, data on the impact and timing of ASD closure and the risk of (recurrent) arrhythmia remains scarce. Purpose To examine the long-term risk of arrhythmia, including the effect and timing of ASD closure in relation to the development and recurrence of arrhythmia. Methods This Danish nationwide cohort study included all patients diagnosed with secundum ASD (1977-2024), followed until arrhythmia, death, emigration, or study end (Jan 2024). The risk of (recurrent) arrhythmias was assessed based on ASD closure status and closure technique. Results Among 6,469 patients with ASD (43.3% men), 34.6% underwent ASD closure (65.5% surgically and 34.5% percutaneously). The incidence rate of arrhythmia was 13.3 (95%CI 12.6-14.2) per 1,000 PY, with atrial fibrillation/flutter being the most prevalent. Older age at diagnosis and closure were linked to higher incidence and recurrence of arrhythmia. Regardless of closure technique, arrhythmia most frequently occurred within the first 30 days or after one year following the ASD closure, Figure 1. In time-dependent Cox regression analyses, surgical ASD closure was associated with an increased risk of arrhythmias compared to no closure (adjusted HR 1.38 [95%CI 1.19-1.60]), whereas no difference was found for percutaneous closure. Overall, three in four patients experienced arrhythmia recurrence. Among those who developed arrhythmias within 30 days after closure, 82% of these developed recurrent arrhythmias during follow-up with rates similar irrespective of closure type. ASD closure was associated with a decreased risk of recurrence, yet statistical significance was observed only when comparing percutaneous closure to no closure (adjusted HR 0.79 [95%CI 0.64–0.98]). Conclusions The incidence rate of arrhythmia among patients with ASD was 13 per 1,000 PY, with age and closure technique being pivotal factors. Surgical closure was associated with an increased risk of arrhythmias compared to no closure, while percutaneous closure was associated with a decreased risk of recurrence.