Impact of pulmonary vein ovality index on cooling kinetics and acute success of atrial fibrillation ablation with the third-generation cryoballoon catheter

Introduction
Atrial fibrillation (AF) is the most common arrhythmia, increasing the risk of stroke and all-cause mortality. Pulmonary vein isolation (PVI) with cryoballoon ablation (CBA) is a widely accepted approach for invasive treatment of patients with AF. CBA effectiveness is considered to be strongly dependent upon the anatomy of pulmonary veins, mainly the ovality of pulmonary veins’ ostia. However, most published results refer to the second-generation cryoballoon.

Aim: To investigate the impact of the ovality index (OI) of pulmonary veins (PVs) on cryokinetic parameters and acute effectiveness of PVI with the third-generation cryoballoon catheter.

Material and methods
We enrolled 54 patients with documented drug-refractory, symptomatic paroxysmal and persistent AF, who underwent CBA with the third-generation cryoballoon between March 2019 and July 2020. Prior to the procedure all patients underwent computed tomography (CT) scans to evaluate anatomy of PVs and calculate the ovality indices for each vein. Analyzed patients were divided into two equal groups depending on the mean OI for all veins.

Results
No differences were observed in acute effectiveness, total procedure time, freeze time, need for additional applications and complications in the group with lower (OI < 1.27) and higher (OI > 1.27) OI values. Remarkably, fluoroscopy time was even slightly shorter (p = 0.046) in patients with high OI.

Conclusions
In the analyzed population, increased pulmonary vein OI had no negative effect on the CBA procedure performed with the third-generation cryoballoon catheter; therefore it can be considered as a more comprehensive single-shot PVI tool.