Second-generation cryoballoon ablation for recurrent atrial fibrillation after an index procedure with radiofrequency versus cryo: Different pulmonary vein reconnection patterns but similar long-term outcome-Results of a multicenter analysis.

INTRODUCTION: Repeated procedures are often needed for long-term success of atrial fibrillation ablation. There are scarce data regarding cryoballoon use for such procedure. METHODS AND RESULTS: We analyzed acute effect and long-term follow-up of second-generation cryoballoon ablation, performed as a repeat procedure after an index radiofrequency vs cryoballoon ablation. Sixty-one patients from three centers were included. In 36 cases radiofrequency (RF-I) and in 25 cryoballoon ablation (CB-I) was the index procedure. During redo procedure, pulmonary vein reconnection was less frequent in CB-I vs RF-I (51.5% vs 66.9%; P = 0.017). After cryoballoon, left inferior (P = 0.027) and right superior (P = 0.06) pulmonary veins were less likely to exhibit reconnection. Moreover, patients after initial RF ablation frequently presented multiple-vein reconnection (P = 0.018), while patients after cryoablation more often had only one vein reconnected (P = 0.008). During reablation procedures, all 149 reconnected veins in both groups were isolated, with no differences in procedural parameters, except for procedure time, shorter in CB-I group (65.5 vs 71.1 minutes; P = 0.04). Transient phrenic nerve palsy was the only complication in both groups (5.6% and 8.0%; ns). After mean follow-up of 15 ± 9 months, 70.3% of patients were free from atrial fibrillation (AF), with no differences between the groups (P = 0.71). In multivariate Cox-regression analysis, the persistent form of arrhythmia (P = 0.009) and relapse in the blanking period (P = 0.0004) were the only independent predictors of AF recurrence. CONCLUSIONS: The use of second-generation cryoballoon is associated with less frequent pulmonary vein reconnection compared with RF ablation. Cryoballoon is safe and effective for repeated AF ablation, regardless of the technique used for the initial procedure.

Impact of pulmonary vein ovality index on cooling kinetics and acute success of atrial fibrillation ablation with the third-generation cryoballoon catheter.

INTRODUCTION: Atrial fibrillation (AF) is the most common arrhythmia, increasing the risk of stroke and all-cause mortality. Pulmonary vein isolation (PVI) with cryoballoon ablation (CBA) is a widely accepted approach for invasive treatment of patients with AF. CBA effectiveness is considered to be strongly dependent upon the anatomy of pulmonary veins, mainly the ovality of pulmonary veins' ostia. However, most published results refer to the second-generation cryoballoon. AIM: To investigate the impact of the ovality index (OI) of pulmonary veins (PVs) on cryokinetic parameters and acute effectiveness of PVI with the third-generation cryoballoon catheter. MATERIAL AND METHODS: We enrolled 54 patients with documented drug-refractory, symptomatic paroxysmal and persistent AF, who underwent CBA with the third-generation cryoballoon between March 2019 and July 2020. Prior to the procedure all patients underwent computed tomography (CT) scans to evaluate anatomy of PVs and calculate the ovality indices for each vein. Analyzed patients were divided into two equal groups depending on the mean OI for all veins. RESULTS: No differences were observed in acute effectiveness, total procedure time, freeze time, need for additional applications and complications in the group with lower (OI < 1.27) and higher (OI > 1.27) OI values. Remarkably, fluoroscopy time was even slightly shorter (p = 0.046) in patients with high OI. CONCLUSIONS: In the analyzed population, increased pulmonary vein OI had no negative effect on the CBA procedure performed with the third-generation cryoballoon catheter; therefore it can be considered as a more comprehensive single-shot PVI tool.

Atrial Fibrillation Ablation with Multipolar Phased-Radiofrequency Catheter: The Learning Curve Effect for Procedural Parameters, but not for the Long-Term Outcome.

BACKGROUND: Pulmonary vein isolation (PVI) is a routine treatment in atrial fibrillation (AF). Single-shot techniques were introduced to simplify the procedure. We analyzed time-dependent changes in procedural parameters, acute success, complication rates, and long-term outcomes during our initial experience with multipolar phased-radiofrequency (RF) ablation. Methods and Results: The first 126 consecutive patients (98 male; age: 58.8 ± 8.7 years) who underwent PVI with phased-RF ablation at our center were included in the study. Procedural parameters, complication rate, acute success and 12-month efficacy were compared in the first, second and third group of 42 consecutive patients. In all patients, 516/526 PVs were effectively isolated (98.1%), with no differences between the tierces (p = 0.67). Procedure (169.8 vs. 132.9 vs. 105.8 min, p < 0.0001), fluoroscopy (32.9 vs. 24.3 vs. 14.1 min, p < 0.0001) and left atrial dwell (83.0 vs. 61.9 vs. 51.4 min, p < 0.0001) times were significantly reduced with experience in tierces 1-3, respectively. In the 12-month follow-up, 60.3% of patients were arrhythmia-free with no differences between the tierces (p = 0.88). In multivariate analysis, the relapse in the blanking period (p < 0.0001), time from AF diagnosis (p = 0.004) and left atrial diameter (p = 0.012) were the only independent predictors of AF recurrence. CONCLUSIONS: The learning curve effect was demonstrated in procedural parameters, but not in the complication rate nor the long-term success of PVI with phased-RF technique. The relapse in the blanking period was the strongest predictor of treatment failure in long-time observation.