Objective:

To investigate the relationship between interatrial septal morphology and atrial fibrillation (AF) recurrence following cryoballoon ablation (CBA).

Approach:

• Study Design: Retrospective single-center cohort study of patients undergoing CBA for paroxysmal or persistent AF between June 2015 and April 2024.
• Patient Assessment: Patients underwent transesophageal echocardiography (TEE) to assess interatrial septal morphology, including patent foramen ovale (PFO), atrial septal aneurysm (ASA), and lipomatous hypertrophy of the interatrial septum (LHIS).
• Outcome Measurement: Primary endpoint was AF recurrence defined as any episode lasting >30 seconds beyond a 90-day blanking period, analyzed using Kaplan–Meier and Cox proportional hazards modeling.

Key Findings:

• PFO was identified in 16.6% of patients, LHIS in 5.7%, and ASA in 1.0%.
• AF recurrence occurred in 26.8% of patients over a median follow-up of 19 months.
• Patients with PFO had a significantly lower AF recurrence rate compared to those without PFO (HR: 0.62; 95% CI: 0.43–0.89; p = 0.010).
• The association between PFO and lower AF recurrence was independent of other confounders (HR: 0.56; 95% CI: 0.38–0.83; p = 0.004).

Interpretation:

The presence of PFO is independently associated with a lower risk of AF recurrence following CBA, suggesting a potential protective role.

Limitations:

• Single-center study may limit generalizability.
• Retrospective design may introduce selection bias.

Conclusion:

The findings indicate a potential protective role of PFO against AF recurrence post-CBA, warranting further prospective investigation.