title: Clinical characteristics and electrophysiologic properties of atrioventricular accessory pathways: importance of the accessory pathway location.
abstract: OBJECTIVE
  This study was designed to assess the influence of accessory atrioventricular (AV) pathway location on the clinical and electrophysiologic characteristics of 384 consecutive symptomatic patients having a single accessory pathway.
  
  
  METHODS
  Four locations were studied: left free wall (n = 270), posteroseptal (n = 52), anteroseptal (n = 29) and right free wall (n = 33). Ten clinical variables and 12 electrophysiologic variables were analyzed, including the effective refractory period of the accessory pathway and the different clinically occurring and inducible arrhythmias.
  
  
  RESULTS
  Only two clinical findings were associated with accessory pathway location: 1) later age at onset of symptoms in the left free wall versus other accessory pathway locations (24 +/- 12 vs. 20 +/- 11 years, p = 0.02), and 2) later age at the time of electrophysiologic study in the left free wall accessory pathway location (36 +/- 13 vs. 32 +/- 11 years, p = 0.01). Six electrophysiologic variables showed a correlation with the accessory pathway location: 1) retrograde conduction only was found less frequently in right free wall (9%) and anteroseptal (10%) than in left free wall (26%) and posteroseptal (29%) accessory pathway locations (p = 0.05); 2) the retrograde effective refractory period of the accessory pathway was shorter in anteroseptal (253 +/- 52 ms) and left free wall (270 +/- 72 ms) as compared with right free wall (296 +/- 101 ms) and posteroseptal (301 +/- 76 ms) locations (p = 0.05); 3) retrograde decremental conduction over the accessory pathway was present in the posteroseptal (17%) and left free wall (3%) but absent in the other locations (p less than 0.001); 4) anterograde decremental conduction was only seen in the right free wall location (12%) (p less than 0.001); 5) orthodromic reentrant tachycardia was induced less frequently in the right free wall than in other locations (70% vs. 93%, p less than 0.001); and 6) inducibility of atrial fibrillation was greater in anteroseptal (62%) than in right free wall (21%), left free wall (44%) and posteroseptal (36%) locations (p = 0.01).
  
  
  CONCLUSIONS
  The location of the accessory AV pathway is associated with specific electrophysiologic characteristics.
authors.affiliation: Department of Cardiology, University of Limburg Academic Hospital, Maastricht, The Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: de Chillou
authors.forename: L M
authors.initials: LM
authors.lastname: Rodriguez
authors.forename: J
authors.initials: J
authors.lastname: Schläpfer
authors.forename: K G
authors.initials: KG
authors.lastname: Kappos
authors.forename: A
authors.initials: A
authors.lastname: Katsivas
authors.forename: X
authors.initials: X
authors.lastname: Baiyan
authors.forename: J L
authors.initials: JL
authors.lastname: Smeets
authors.forename: H J
authors.initials: HJ
authors.lastname: Wellens
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D001281:Atrial Fibrillation / Q000503:physiopathology; D001283:Atrioventricular Node / Q000503:physiopathology*; D002648:Child; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000503:physiopathology; D014927:Wolff-Parkinson-White Syndrome / Q000503:physiopathology*