title: Accuracy of the Electrocardiogram in Localizing the Accessory Pathway in Patients with Wolff-Parkinson-White Pattern.
abstract: BACKGROUND
  There are currently several electrocardiographic algorithms to locate the accessory pathway (AP) in patients with Wolff-Parkinson-White (WPW) syndrome.
  
  
  OBJECTIVE
  To compare the ability of electrocardiographic algorithms in identifying the location of the AP in patients with WPW pattern referred for ablation.
  
  
  METHODS
  Observational, cross-sectional, retrospective study with 111 patients with WPW syndrome referred for AP ablation. The electrocardiogram (ECG) obtained prior to the ablation was analyzed by an experienced observer who consecutively applied seven algorithms to identify non-invasively the AP. We then compared the location estimated with this assessment with that obtained in the electrophysiological study and calculated the agreement rates.
  
  
  RESULTS
  Among the APs, 59 (53.15%) were distributed around the mitral annulus and the remaining 52 (46.85%) were located around the tricuspid annulus. The overall absolute accuracy of the algorithms evaluated varied between 27% and 47%, increasing to between 40% and 76% when we included adjacent locations. The absolute agreement rate by AP location was 2.00-52.20% for septal APs (n = 51), increasing to 5.90-90.20% when considering adjacent locations; 7.70-69.20% for right APs (n = 13), increasing to 42.90-100% when considering adjacent locations; and 21.70-54.50% for left APs (n = 47), increasing to 50-87% when considering adjacent locations.
  
  
  CONCLUSIONS
  The agreement rates observed for the analyzed scores indicated a low discriminative ability of the ECG in locating the AP in patients with WPW.
authors.affiliation: Departamento de Fisiologia Clínica, ESTESC, Instituto Politécnico de Coimbra, Coimbra, Portugal.
authors.forename: Carlos Manuel
authors.initials: CM
authors.lastname: Teixeira
authors.affiliation: Departamento de Fisiologia Clínica, ESTESC, Instituto Politécnico de Coimbra, Coimbra, Portugal.
authors.forename: Telmo António
authors.initials: TA
authors.lastname: Pereira
authors.affiliation: Serviço de Cardiologia, Centro Hospitalar São João, Porto, Portugal.
authors.forename: Ana Margarida
authors.initials: AM
authors.lastname: Lebreiro
authors.affiliation: Departamento de Fisiologia Clínica, ESTESC, Instituto Politécnico de Coimbra, Coimbra, Portugal.
authors.forename: Sérgio Alexandre
authors.initials: SA
authors.lastname: Carvalho
mesh_terms: D058606:Accessory Atrioventricular Bundle / Q000175:diagnosis* / Q000503:physiopathology; D000328:Adult; D000465:Algorithms; D017115:Catheter Ablation; D003430:Cross-Sectional Studies; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014927:Wolff-Parkinson-White Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D055815:Young Adult