Introduction: Although recent publications have further supported the role of cryoballoon guided pulmonary vein isolation (PVI) in the therapy of atrial fibrillation (AF), there remains a significant percentage of patients who develop recurrent AF episodes after initial successful cryoballoon PVI due to reconnected pulmonary veins (PV). Based on the data from Re-Do procedures, we sought out to identify predictors of PV reconnection.

Methods and results: From a single centre prospective registry, we identified a total of 104 Patients who underwent Re-Do procedures between 2018 and 2021 after an initial cryoballoon ablation. Re-Do procedures were performed using high density 3D mapping systems (CartoÒ, Navx EnsiteÒ, and RhythmiaÒ). Index procedures were performed following a time to isolation (TTI) guided protocol, energy delivery was in general limited to 1 Freeze of 180s per Vein if TTI < 60s. In 69 patients (66% of the Re-Do procedures) we saw at least one reconnected vein (mean 1,6 ± 0.7 veins reconnected; 3 PV reconnected in 9 patients, 2 PV reconnected in 20 patients, 1 PV reconnected in 35 patients). In most cases, the right superior PV was reconnected (n = 45), followed by the left superior PV (n = 26), the left inferior PV (n = 19), and the right inferior PV (n = 18). In comparison to patients with persistent PV isolation we saw no statistical differences in patients’ characteristics at the time of index procedure: age (p = 0.24), BMI (p = 0.37), gender (p = 0.46), left atrial volume index (LAVI) (p = 0.40), ejection fraction (EF) (p = 0.92), CHA₂DS₂ Vasc score (p = 0.21), glomerular filtration rate (p = 0.65), creatinine (p = 0.59), years since AF diagnosis (p = 0.88), type of AF (p = 0.19). Further, regarding the index procedure we further saw no differences in both groups (no PV reconnection vs. at least one PV reconnection) regarding number of freezes needed to isolate, lowest temperature or the time to isolation achieved for the left superior PV (p = 0.66; p = 0.18; p = 0.69), the left inferior PV (p = 0.30; p = 0.26; p = 0.11), the right superior PV (p = 0.26; p = 0.20; p = 0.92), the right inferior PV (p = 0.38; p = 0.19; p = 0.85).

Conclusion: In Re-Do procedures for recurrent AF after an index cryoballoon mediated PVI, 66% of the patients with recurrent AF presenting for a Re-Do showed at least one PV reconnection. The highest reconnection rate was seen in the right superior PV. We saw no predictors for PV reconnection analysing baseline characteristics at the time of cryoballoon PVI nor procedural data of the index procedure.