Reduced recurrence of atrial fibrillation after cryoballoon ablation in patients with preprocedural patent foramen ovale: a retrospective single-center observational cohort study

Background Atrial septal anomalies such as patent foramen ovale (PFO), atrial septal aneurysm (ASA), and lipomatous hypertrophy of the interatrial septum (LHIS) are frequently identified by transoesophageal echocardiography (TEE) in patients undergoing atrial fibrillation (AF) ablation. While ASAs have been linked to arrhythmogenic potential, their influence on post-ablation outcomes, particularly after cryoballoon ablation (CBA), is poorly understood. Methods In this retrospective single-center cohort study we enrolled all patients who underwent CBA-based pulmonary vein isolation (PVI) for paroxysmal or persistent AF between June 2015 and April 2024 at our center and had preprocedural TEE imaging. Interatrial septal morphology—including PFO, ASA, and LHIS—was assessed. The primary endpoint was AF recurrence, defined as any episode lasting >30 s beyond the 90-day blanking period. Kaplan–Meier analysis and Cox proportional hazards modeling were used for time-to-event analyses. Results Among 657 patients (mean age 61.7 ± 9.6 years; 71.2% male), PFO was identified in 16.6%, LHIS in 5.7%, and ASA in 1.0%. Over a median follow-up of 19 months (IQR: 3–76), AF recurrence occurred in 26.8%. Kaplan–Meier analysis revealed a significantly lower recurrence rate in patients with PFO compared to those without PFO (HR: 0.62; 95% CI: 0.43–0.89; p = 0.010). This association was independent from other clinical, electrophysiological and echocardiographic confounders (HR: 0.56; 95% CI: 0.38–0.83; p = 0.004). Conclusions In this single-center cohort, the presence of PFO was independently associated with a lower risk of AF recurrence following CBA. These findings suggest a potential protective role of PFO and merit further prospective investigation.