title: Learning curve in circular multipolar phased  radiofrequency ablation of atrial fibrillation.
abstract: BACKGROUND
  Although atrial fibrillation (AF) ablation is considered a technically challenging procedure, studies on the learning curve of different pulmonary vein isolation (PVI) techniques are limited. We investigated the time-dependent changes in procedural parameters, complication rates, and in the 1-year clinical outcome during our initial experience with circular multipolar phased radiofrequency (RF) ablation.
  
  
  RESULTS
  The first 132 consecutive patients (40 female; age: 56.6 ± 10.4 years) who underwent PVI with phased RF ablation for paroxysmal or persistent AF at our center were included in the study. Procedural parameters and atrial arrhythmia-free survival were compared in the first, second and third group of 44 successive patients. All pulmonary veins were successfully isolated in 44 (100%), 41 (93.8%) and 42 (95.5%) patients in Tierce 1, 2 and 3, respectively (p = 0.233). The number of RF applications (per vein) required for isolation and fluoroscopy times demonstrated a significant decrease with experience, and a trend towards lower procedure times in Tierces 2 and 3 was also observed. Atrial arrhythmia-free survival rates at 12 months postablation were 68.18%, 75%, and 70.75% in Tierce 1, Tierce 2 and Tierce 3, respectively (p = 0.772). Pericardial tamponade requiring percutaneous subxiphoid drainage occurred in 1 patient (Tierce 3) as the only significant procedural complication.
  
  
  CONCLUSIONS
  A learning curve effect was demonstrated in fluoroscopy times and in the number of RF applications but not in the acute success and in the long-term arrhythmia-free survival with circular multipolar RF ablations.
authors.forename: Mihran
authors.initials: M
authors.lastname: Martirosyan
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kiss
authors.forename: Edina
authors.initials: E
authors.lastname: Nagy-Baló
authors.forename: Gábor
authors.initials: G
authors.lastname: Sándorfi
authors.forename: Diana
authors.initials: D
authors.lastname: Tint
authors.forename: István
authors.initials: I
authors.lastname: Édes
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Csanádi
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D002305:Cardiac Tamponade / Q000209:etiology / Q000628:therapy; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D002983:Clinical Competence; D018572:Disease-Free Survival; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D015641:Radiography, Interventional; D013997:Time Factors; D016896:Treatment Outcome