title: Radiofrequency catheter ablation of accessory atrioventricular pathways: primary failure and recurrence of conduction.
abstract: OBJECTIVE
  To identify possible factors associated with primary failure of radiofrequency ablation of accessory pathways or recurrence of accessory pathway conduction.
  
  
  METHODS
  Radiofrequency ablation of accessory pathways failed in 25 of 243 patients, and recurrence of accessory pathway conduction occurred in an additional 13 patients. Factors possibly related to primary failure and recurrence were analysed.
  
  
  RESULTS
  Primary failure and recurrence were less frequent in patients with left sided pathways (7% v 19%; 4% v 24%; P = 0.04). The factors that might relate to primary failure included an unstable catheter position (seven patients), a possible epicardial pathway (six patients), or misdiagnosis of accessory pathway location (two patients). The major factors for recurrence included the stability of the local atrial electrogram < or = 0.5 together with the stability of the local ventricular electrogram < or = 0.8, and prolonged time to pathway conduction block > or = 12 seconds). Thirty one patients underwent repeat ablation which was successful in 28.
  
  
  CONCLUSIONS
  Primary failure and recurrence were more frequent in patients with right sided pathways. An unstable catheter position and a possible epicardial pathway location are the main contributing factors for primary failure, while unstable local electrograms and prolonged time to block are independent predictors for recurrence.
authors.affiliation: Department of Cardiological Sciences, St George's Hospital Medical School, London.
authors.forename: B
authors.initials: B
authors.lastname: Xie
authors.forename: S C
authors.initials: SC
authors.lastname: Heald
authors.forename: A J
authors.initials: AJ
authors.lastname: Camm
authors.forename: E
authors.initials: E
authors.lastname: Rowland
authors.forename: D E
authors.initials: DE
authors.lastname: Ward
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation; D005260:Female; D006329:Heart Conduction System / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence; D012086:Reoperation; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery*; D017211:Treatment Failure