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.