Impact of Carina Width on Re‐Ablation Rate of Atrial Fibrillation After Primary Cryoballoon‐Ablation

BACKGROUND: Reconnection of the pulmonary veins (PVs) is the primary cause of atrial fibrillation (AF) episodes after pulmonary vein isolation (PVI). Cryoballoon ablation does not always include the isolation of the carina due to anatomic variants and carina width has been associated with increased re-ablation rate in previous radiofrequency ablation studies. Aim of our study was to assess the impact of carina width on the re-ablation rate after cryoballoon-PVI. METHODS: We included 518 patients who underwent cryoballoon ablation for AF between 2015 and 2022. Each patient underwent contrast enhanced chest computed tomography (CT) scan prior to ablation. We measured the shortest distance between the superior and inferior PV (carina width) and the size of the left atrium in CT images. In patients referred to re-ablation due to recurring symptomatic and ECG documented AF we defined the reconnected veins. The minimum follow up after prior PVI was 1 year. RESULTS: In all patients the right carina was wider than the left (8.04 ± 4.49 mm vs. 5.25 ± 3.03 mm, p < 0.059). One fifth (n = 102) of the patients underwent re-ablation for AF. Left carina width was significantly associated with re-ablation rate (in re-ablation group 6.4 ± 2.7 mm vs. in no re-ablation group 4.9 ± 3.0 mm, p < 0.001) whereas right carina width was not (8.3 ± 3.0 mm vs. 7.9 ± 3.6 mm, p = 0.421, respectively). Left atrium (LA) was larger in the re-ablation group, but the size of the LA did not correlate with the left carina width (r = 0.075; p = 0.111). However, there was a significant correlation between the size of the LA and the width of the right carina (r = 0.251, p < 0.001). Also, in the re-ablation group a significant correlation between right carina width and reconnection of the right PV's (RPV) was detected, which was not seen in the left PV's (LPV) (p = 0.015; p = 0.360, respectively). CONCLUSION: The left carina width and LA size are associated with the success rate of primary cryoballoon-PVI. However, there was a correlation between the right carina width and the reconnection of the RPV's leading to re-ablation. It seems that recognition of anatomical variants could be useful in the decision of ablation technique, but further studies are needed.