Introduction: The most common cause of atrial fibrillation (AF) recurrence after ablation is pulmonary vein (PV) reconnections. At least 20% of the patients are subjected to repeated procedures after the first intervention. It is assumed that isolation lines made by cryoballoon (single-shot technique are more uniform and durable than those created by the radiofrequent (RF) “point by point” technique (1).

Methods: We did a retrospective analysis of repeated PV isolation procedures at University Hospital Centre Zagreb. Redo procedures were performed in patients who had symptomatic recurrence of AF after the first ablation despite antiarrhythmics. The interventions were performed in local anesthesia with intracardial ultrasound, CARTO 3 system and contact sensing RF catheters. The intent of the second procedure was the re-isolation of reconnected veins. The aim of this study was to compare the characteristics of repeat procedures and the number of reconnected veins after the initial ablation with the cryoballoon compared to the initial ablation with the RF catheters.

Results: We have analyzed 16 repeat procedures, 7 of which were after the first cryoballon procedure (CB group) and 9 after ablation with RF energy (RF group). Most patients were men (75%) of average age 62±7.8 years. The most had paroxysmal (75%), and the rest had a persistent FA. The mean left atrial size was 44.6±4.8 mm and mean left ventricle ejection fraction was 61.3±7.4%. There were no significant differences between the basic characteristics of the groups. In the CB group there were 12/26 (46%) PV with reconnections, compared to 26/36 (72%) in the RF group (p=0.396). The procedure duration was 122.8±40.8 min in the CB group, and 190.5±69.8 min in the RF group (p=0.039). The fluoroscopy time in the CB group was 19.7±9.1 min, and in the RF group 22.5±12.0 min (p=0.616). The duration of RF ablation was shorter in the CB group, 558.6±320.2 and in the RF group 1904.5±608.1 (p <0.0001). No complications were observed, and 25% of the patients had recurrent FA.

Conclusion: After the initial ablation with the second generation cryoballoon (vs. RF energy), we can expect less reconnected PVs in the second intervention, resulting in shorter redo procedures with less need for RF ablation. Due to the small number of patients, not all differences are statistically significant.