Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
Pulmonary vein (PV) isolation is a cornerstone ablation strategy in the management of patients with atrial fibrillation (AF). PV frequently display anatomical variants, which may compromise the results of cryoballoon ablation (CBA).
Purpose
We aimed to determine PV variation patterns in real-world patients undergoing CBA for AF and their impact on procedural success using a multicentre electronic medical records (Casiopea) sharing cardiac computed tomography (CT) scan studies performed in the referring centres and evaluated prior to the procedure in the EP reference hospital.
Methods
We included consecutive patients with paroxysmal or persistent AF who referred for CBA to a EP reference hospital in Spain from 2017 to 2021. All patients underwent systematic standardized CBA. Prior to the procedure, PV variation and left atrium (LA) size were evaluated in all patients by CT- scan. Blinded data were analysed by a imaging Core Lab. PV and LA anatomy were evaluated in 3-dimensional reconstructions using EnSite NavX electroanatomic mapping system. Ablation procedure was performed using either 23 or 28 mm cryoballoon according to the operator's criteria and potential predictors for AF recurrence were recorded.
Results
104 patients were included (mean age 58±8 year-old, 85% male). 76 patients (73%) had recurrent paroxysmal AF, failure of antiarrhythmic drugs was present in 96% and prior radiofrequency ablation in 4%. Conventional PV anatomy consisting in 4 veins was present in 83 patients (80%), left or right common vein in 13 (13%) and accessory veins in 8 (7%). Figure. 61 patients (59%) showed left atria enlargement (> 40 mm or area > 20 cm2). CBA was performed using a 28 mm cryoballoon in 98 patients (94%). Temperature achieved during ablation was below -40°C in all the veins in 80% of the procedures. Procedural-related complications occurred in 6 patients (5%), transient phrenic nerve palsy in 2 patients and vascular damage in 4. All patients were under antiarrhythmic drugs and continued for at least 6 months after the procedure. After 19±9 months of follow-up, freedom from AF recurrence after the blanking period was 73%. Univariate analyses identified the following baseline characteristics predicted AF recurrence: prior ablation (OR = 3.6 p=0.03; 95% CI 1.1-12.3), complete PV isolation with temperature below -40°C (OR = 0.16 p = 0.001; 95% CI 0.05-0.48) and AF recurrence during the blanking period (OR = 6.3, p <0.001; 95% CI 2.9-13.8). PV anatomy was not a limitation nor a predictor for AF recurrences in the long-term follow-up (OR = 0.56 p = 0.17; 95% CI 0.24-1.28).
Conclusion
This evaluation of multicentre electronic medical records sharing CT scan studies prior CBA showed that the procedure was safe and effective with regard to the PV anatomy. The presence of anatomical variants of PV should not discourage about efficacy and it is not a limitation for CBA.
