title: Learning curve for ablation of atrial fibrillation in medium-volume centers.
abstract: OBJECTIVE
  We evaluated whether time-dependent procedural improvement was independently associated with reduction in atrial fibrillation (AF) recurrences or periprocedural complications in patients who underwent catheter ablation for AF at a single medium-volume center.
  
  
  METHODS
  A total of 208 consecutive patients who underwent AF ablation from June 2006 to June 2009 were enrolled. All procedures were performed by an experienced operator, and the ablation protocol, devices, and equipment remained unchanged throughout the study period. The study period was divided into quarters (1-4 Q) to include the same number of patients within each quarter. The incidence of AF recurrences or periprocedural complications requiring a prolonged hospital stay or surgical intervention was retrospectively compared across the quarters.
  
  
  RESULTS
  During follow-up (15 ± 3 months), we observed 26 (13%) AF recurrences (27% in 1Q, 15% in 2Q, 6% in 3Q, 2% in 4Q; 1Q vs. 3Q, p=0.0035; 1Q vs. 4Q, p=0.0003; 2Q vs. 4Q, p=0.013) and 15 (7%) periprocedural complications (12% in 1Q, 8% in 2Q, 6% in 3Q, 4% in 4Q), both of which declined progressively over time. Multiple logistic regression analysis revealed that 1Q, but not any other patient background parameters, was an independent predictor of the incidence of AF recurrence or periprocedural complications (odds ratio, 2.45; 95% confidence interval, 1.19-5.20; p=0.015).
  
  
  CONCLUSIONS
  The time period when the procedure was performed significantly influenced the AF ablation outcome, indicating that operators in medium-volume centers should be committed to providing gratifying outcomes particularly early in the institutional experience with AF ablation.
authors.affiliation: Department of Cardiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. rjrgw059@ybb.ne.jp
authors.forename: Akinori
authors.initials: A
authors.lastname: Sairaku
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nakano
authors.forename: Noboru
authors.initials: N
authors.lastname: Oda
authors.forename: Yuko
authors.initials: Y
authors.lastname: Makita
authors.forename: Kenta
authors.initials: K
authors.lastname: Kajihara
authors.forename: Takehito
authors.initials: T
authors.lastname: Tokuyama
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Kihara
mesh_terms: D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000592:standards; D005260:Female; D006801:Humans; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012044:Regression Analysis; D016896:Treatment Outcome