Impact of the carina width in atrial fibrillation re-ablation after primary cryo-ablation

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 in the re-ablation rate after cryoballoon PVI.

We included 518 patients who underwent cryoballoon ablation for AF between 2015-2022. Each patient underwent contrast enhanced Thorax- CT scan prior to ablation. We measured the shortest distance between the superior and inferior vein (carina width) and the size of the left atrium in a 3D reconstruction model of the left atrium. In patients referred to re-ablation due to recurring symptomatic and ECG documented AF we defined the re-connected veins. The follow up after prior PVI was a minimum of 1 year.

In all patients the right carina was wider than the left (8,04±4,49 mm; 5,25 ± 3,03mm). 102 (20%) underwent re-ablation for AF. Left side carina width was associated with re-ablation (Left carina: Re-ablation 6,4± 2,7 mm versus control 4,9±3,0, p < 0,001; right carina: Re-ablation 8,3± 3,0 mm versus control 7,9±3,6 mm, p = 0,42). Left atrium was larger in the re-ablation population, but the size of the left atrium did not correlate with the left carina width (r=0,75; p=0,11). However, there was a significant correlation between the size of the atrium and the width of the right carina (r=0,25, p< 0,01). Also in the re-ablation population we found a significant association between right carina width and re-connection of the right veins which was not seen in the left sided veins (p= 0,015; p= 0,36, respectively).

There seems to be an association of left carina width and success rate of primary cryoballoon ablation. However, there was also an association of right carina width and the re-connection of the right sided veins leading to re-ablation. It seems that anatomical features could affect the choice of ablation technique, but further studies are needed.