title: Characterization of fractionated atrial electrograms critical for maintenance of atrial fibrillation: a randomized, controlled trial of ablation strategies (the CFAE AF trial).
abstract: BACKGROUND
  Whether ablation of complex fractionated atrial electrograms (CFAE) modifies atrial fibrillation (AF) by eliminating drivers or atrial debulking remains unknown. This randomized study aimed to determine the effect of ablating different CFAE morphologies compared with normal electrograms (ie, debulking normal tissue) on the cycle length of persistent AF (AFCL).
  
  
  RESULTS
  After pulmonary vein isolation left and right atrial CFAE were targeted, until termination of AF or abolition of CFAE before DC cardioversion. Ten-second electrograms were classified according to a validated scale, with grade 1 being most fractionated and grade 5 normal. Patients were randomly assigned to have CFAE grades eliminated sequentially, from grade 1 to 5 (group 1) or grade 5 to 1 (group 2). An increase in AFCL (mean of left and right atrial appendage) ≥5 ms after a lesion was regarded as significant. CFAE (n=968) were targeted in 20 patients. AFCL increased after targeting 51±35% of grade 1 CFAE, 30±15% grade 2, 12±5% grade 3, 33±12% grade 4, and 8±15% grade 5 CFAE (P<0.01 for grades 1, 2, and 4 versus 5; 3 versus 5, not significant). The proportion of lesions causing AFCL prolongation was unaffected by the order in which CFAE were targeted.
  
  
  CONCLUSIONS
  Targeting CFAE is not simply atrial debulking. Ablating certain grades of CFAE increases AFCL, suggesting they are more important in maintaining AF.
  
  
  BACKGROUND
  URL: http://www.clinicaltrials.gov. Unique identifier: NCT00894400.
authors.affiliation: Cardiology Department, Barts and The London NHS Trust QMUL, St Bartholomew's Hospital, London, United Kingdom.
authors.forename: Ross J
authors.initials: RJ
authors.lastname: Hunter
authors.forename: Ihab
authors.initials: I
authors.lastname: Diab
authors.forename: Muzahir
authors.initials: M
authors.lastname: Tayebjee
authors.forename: Laura
authors.initials: L
authors.lastname: Richmond
authors.forename: Simon
authors.initials: S
authors.lastname: Sporton
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Earley
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Schilling
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011667:Pulmonary Veins / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome