title: Importance of accessory pathway location in the efficacy and safety of radiofrequency ablation.
abstract: BACKGROUND
  Atrioventricular accessory pathways can be asymptomatic, or can cause reentrant tachycardia and, rarely, sudden cardiac death. In general, radiofrequency ablation is the curative treatment of choice. The aim of this study was to determine the importance of accessory pathway location in the efficacy and safety of radiofrequency ablation.
  
  
  METHODS
  We performed a cross-sectional study based on the clinical and electrophysiological data of 858 consecutive patients undergoing accessory pathway radiofrequency ablation in our hospital between November 1997 and December 2008.
  
  
  RESULTS
  Median age was 37.2 +/- 19.8 years (56.0% males); most patients were symptomatic (94.2%) and without structural heart disease (95.1%). The prevalence of concealed pathways was 28.0%. Slightly over half of the patients were on antiarrhythmic therapy. The anatomical distribution of the accessory pathways was as follows: left ventricular free wall (LVFW) (53.8%), posteroseptal (25.6%), right ventricular free wall (7.7%), anteroseptal (4.3%), midseptal (3.5%) and multiple (5.0%). The acute success rate was highest in LVFW accessory pathways (97.0%) and lowest in multiple accessory pathways (88.4%). Significant complications occurred in 0.5% of cases, midseptal and anteroseptal accessory pathways being most affected (3.3% and 2.7%, respectively). At one-year follow-up there were no deaths, and 4.4% of patients had recurrence of accessory pathway conduction, with no significant differences between anatomical locations.
  
  
  CONCLUSIONS
  The anatomical position of the accessory pathway affects the efficacy and safety of radiofrequency ablation.
authors.affiliation: Serviço de Cardiologia, Centro Hospitalar de Vila Nova de Gaia/Espinho, Vila Nova de Gaia, Portugal. luis_adao@hotmail.com
authors.forename: Luís
authors.initials: L
authors.lastname: Adão
authors.forename: Carla
authors.initials: C
authors.lastname: Araújo
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Sá
authors.forename: Paula
authors.initials: P
authors.lastname: Silva
authors.forename: Marco
authors.initials: M
authors.lastname: Oliveira
authors.forename: Helena
authors.initials: H
authors.lastname: Gonçalves
authors.forename: João
authors.initials: J
authors.lastname: Primo
authors.forename: Vasco
authors.initials: V
authors.lastname: Gama
mesh_terms: D058606:Accessory Atrioventricular Bundle / Q000145:classification / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000188:drug therapy; D017115:Catheter Ablation / Q000379:methods*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000889:Anti-Arrhythmia Agents