Background. Cryoballoon-guided atrial fibrillation (AF) ablation has been established for single-shot pulmonary vein isolation (PVI). Only limited data exists about the impact of the pulmonary vein (PV) anatomy and their related ostial dimensions on AF recurrence following PVI with single-shot devices.

Objectives. This observational single-center analysis aimed to assess the role of individual anatomical characteristics to predict freedom from arrhythmia recurrence after cryoballon-guided PVI in AF patients.

Methods. We analysed data from AF patients, who underwent cryoballoon-guided single-shot PVI between 2012 and 2018. The individual pulmonary venous and left atrial (LA) anatomy was assessed using time-resolved Pulmonary contrast-enhanced magnetic resonance angiograph (CE-MRA).  For each PV, the diameter in coronal (D1) and transversal (D2) plane were measured and the cross-sectional area (CSA) was calculated. Patients were divided into two sub-groups based on AF recurrence within 12 months after ablation. Uni- and multivariate analysis was performed to estimate predictors for AF recurrence.

Results. MRI of 353 patients (197 males, 58±2 years) undergoing cryoballoon PVI were analysed. Regular PV anatomy (2 left- and 2 right-sided pulmonary veins) was present in 237 patients (67 %). CMR revealed the following anatomical variants: left common ostium (LCPV; n= 92; 25 %), right-sided accessory PV (n=16; 5%), right common ostium (RCPV; n=12; 3%). In patients without AF recurrence, variant PV anatomy was distributed as follows: LCPV n=75; 27%, right-sided accessory PV n=9; 3% and RCPV n=9; 3%.  In addition, the mean CSA was 259.1 ± 66.7 mm² for the RSPV, 234.8 ± 69.6 mm² for the RIPV, 218.0 ± 70.7 mm² for the LSPV and 159.0 ± 44.7 mm² for the LIPV, respectively and LCPV was 311.0 ± 60 mm². AF recurrence was documented in 68 patients (19%).  In patients with AF recurrence, variant PV anatomy was as followed: LCPV n=17; 25%, right-sided accessory pulmonary vein n=7; 10 % and RCPV n=3; 4 %. The mean CSA was: 260.0 ±76.0 mm² for the RSPV, 250.0 ± 93.3 mm² for the RIPV, 234.8 ± 69.6 mm² for the LSPV, 163.3 ± 58.8 mm² for the LIPV and 355.6±60 mm² for LCPV. Although the mean CSA of the PVs (overall and per pulmonary vein) was enlarged in patients with AF recurrence, this finding was not a significant predictor for arrhythmia recurrence (p>0.05). Variant PV anatomy in terms of a right-sided accessory PV was a significant predictor for AF recurrence (p= 0.01).

Conclusion. Variant PV anatomy, but not the ostial area, predicted AF recurrence following single-shot device guided cryoablation. Preprocedural imaging may help to improve patient selection for single-shot device guided PVI using the cryoballoon. Complete occlusion of the PVs resulting in adequate lesion formation can be achieved in almost all PVs irrespective of the ostial dimensions.