title: Cryoballoon ablation of pulmonary veins for paroxysmal atrial fibrillation: first results of the North American Arctic Front (STOP AF) pivotal trial.
abstract: OBJECTIVE
  This study sought to assess the safety and effectiveness of a novel cryoballoon ablation technology designed to achieve single-delivery pulmonary vein (PV) isolation.
  
  
  BACKGROUND
  Standard radiofrequency ablation is effective in eliminating atrial fibrillation (AF) but requires multiple lesion delivery at the risk of significant complications.
  
  
  METHODS
  Patients with documented symptomatic paroxysmal AF and previously failed therapy with ≥ 1 membrane active antiarrhythmic drug underwent 2:1 randomization to either cryoballoon ablation (n = 163) or drug therapy (n = 82). A 90-day blanking period allowed for optimization of antiarrhythmic drug therapy and reablation if necessary. Effectiveness of the cryoablation procedure versus drug therapy was determined at 12 months.
  
  
  RESULTS
  Patients had highly symptomatic AF (78% paroxysmal, 22% early persistent) and experienced failure of at least one antiarrhythmic drug. Cryoablation produced acute isolation of three or more PVs in 98.2% and all four PVs in 97.6% of patients. PVs isolation was achieved with the balloon catheter alone in 83%. At 12 months, treatment success was 69.9% (114 of 163) of cryoblation patients compared with 7.3% of antiarrhythmic drug patients (absolute difference, 62.6% [p < 0.001]). Sixty-five (79%) drug-treated patients crossed over to cryoablation during 12 months of study follow-up due to recurrent, symptomatic AF, constituting drug treatment failure. There were 7 of the resulting 228 cryoablated patients (3.1%) with a >75% reduction in PV area during 12 months of follow-up. Twenty-nine of 259 procedures (11.2%) were associated with phrenic nerve palsy as determined by radiographic screening; 25 of these had resolved by 12 months. Cryoablation patients had significantly improved symptoms at 12 months.
  
  
  CONCLUSIONS
  The STOP AF trial demonstrated that cryoballoon ablation is a safe and effective alternative to antiarrhythmic medication for the treatment of patients with symptomatic paroxysmal AF, for whom at least one antiarrhythmic drug has failed, with risks within accepted standards for ablation therapy. (A Clinical Study of the Arctic Front Cryoablation Balloon for the Treatment of Paroxysmal Atrial Fibrillation [Stop AF]; NCT00523978).
authors.affiliation: Mayo Clinic, Rochester, Minnesota. Electronic address: packer@mayo.edu.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Packer
authors.forename: Robert C
authors.initials: RC
authors.lastname: Kowal
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Wheelan
authors.forename: James M
authors.initials: JM
authors.lastname: Irwin
authors.forename: Jean
authors.initials: J
authors.lastname: Champagne
authors.forename: Peter G
authors.initials: PG
authors.lastname: Guerra
authors.forename: Marc
authors.initials: M
authors.lastname: Dubuc
authors.forename: Vivek
authors.initials: V
authors.lastname: Reddy
authors.forename: Linda
authors.initials: L
authors.lastname: Nelson
authors.forename: Richard G
authors.initials: RG
authors.lastname: Holcomb
authors.forename: John W
authors.initials: JW
authors.lastname: Lehmann
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Ruskin
mesh_terms: D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D003452:Cryosurgery / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009656:North America; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents