Introduction: Cryoballoon ablation (CBA) is non-inferior to radiofrequency catheter ablation (RFCA) in efficacy and safety of catheter ablation for paroxysmal atrial fibrillation (AF). But, little data on the impact of operator experience on the outcomes are available.
Methods: A total of 306 consecutive patients (62.5±10.0 years) who underwent initial catheter ablation for paroxysmal AF at our institute using an irrigated radiofrequency catheter with contact force sensing technology or a 28mm second-generation cryoballoon from Jun 2014 to Dec 2015 were identified. Seven operators were classified into 2 groups based on the operation volume per year: 2 high volume operators performing first-time AF ablation of ≥100 cases/year were included in group-A, and five low volume operators performing <100 cases/year in group-B. The mid-term efficacy of ablation during median follow-up of 20 months (interquartile range 15, 24) was compared between the groups.
Results: Patients treated with RFCA (n=176) showed similar AF recurrence rates with a 3-month blanking period, to those with CBA (n=130) (RFCA vs. CBA; 23.2% vs. 26.1%, Log-rank P=0.29). Whereas, absence of recurrence was more common in group A than in group B (Group A vs. Group B, 72/78 [92.3%] vs. 63/98 [64.2%]; Log-rank P<0.001). In these patients, a lower-volume operator was an independent predictor of AF recurrence even after adjustment for age, sex, and left atrial diameter in the multivariate model (hazard ratio 5.67, 95% confidence interval 2.54-15.11; P<0.001). In patients treated with CBA, the recurrence free ratio was similar between the groups (24/95 [74.7%] versus 25/35 [71.4%]; Log-rank P= 0.53), and a low volume operator was not associated with AF recurrence (hazard ratio 1.27, 95% confidence interval 0.57-2.62; P=0.52).
Conclusions: Operator proficiency was related to a successful outcome after AF ablation with RFCA but such a relation was not observed in those with CBA.