Why do women have a higher risk of recurrence following atrial fibrillation ablation? - Gender specific analysis of pulmonary vein isolation durability at repeat ablation

Background:
Pulmonary vein isolation (PVI) by means of cryoballoon ablation (CBA) is safe and effective to achieve durable PVI at a first procedure. However, patients still experience recurrences of atrial arrhythmias, due to electrical reconnection of pulmonary veins (PVs) during follow-up. Higher rates of atrial arrhythmia recurrences in women are reported and it is unclear whether this is due to PV reconnection. The aim of the study was to evaluate gender specific differences in reconnection rates of patients undergoing repeat ablation after initial CBA due to recurrences of atrial arrhythmias.

Methods:
From the prospective observational single-center registry, all patients undergoing repeat ablation due to recurrences of atrial arrhythmias after a single initial advanced CBA were included in this analysis. The initial CBA was performed according to a standardized CBA protocol with a rigid cut off for bonus application with optimized repositioning (TTI > 45sec.) and applications of 180 sec. In all PVs without TTI, a bonus application was performed following the electrical disconnection. In PVs with TTI >90s the freeze was terminated, and the balloon was repositioned.

At repeat ablation, ultra-high density electroanatomical 3D mapping (voltage and activation) of the LA was performed, including analysis of PV reconnection. Durable PVI at repeat ablation was analyzed and compared for men and women. Statistical analysis was performed with SPSS and established descriptive methods.

Results:
A total of 2,410 patients underwent CBA performed with generation 2, 3 or 4 between 5/2012 and 3/2021. After a median time span of 15 months, a total of 219 patients (9.1%) underwent repeat ablation, and of those 150 (69%) patients presented with persistent AF. Median age was 70 years. Ninety-three (42%) were female. Durable PVI of all veins was found in 139/219 patients (63.5%). Durable isolation of all PVs was significantly more frequent in women compared to men (73.1% vs. 56.3% p = 0.009). In 219 patients, a total number of 856 PVs were evaluated. Of those, 95 PVs (11.1%) showed reconnection.

Analysis of each PV-type showed a significantly lower PV reconnection rates for the right superior PV in women and men (8.00% vs. 17.7 p=0.04).

Conclusion:
Gender-specific analysis of pulmonary vein isolation durability at repeat ablation reveals that women have a higher rate of complete durable pulmonary vein isolation and a lower number of reconnected veins compared to men, suggesting that pulmonary vein reconnection does not explain the higher recurrence rates of atrial arrhythmias in women.