title: Electrocardiogram in patients with fasciculoventricular pathways: a comparative study with anteroseptal and midseptal accessory pathways.
abstract: OBJECTIVE
  The purpose of this study was to describe the ECG profile of a cohort of patients with fasciculoventricular pathways and compare the profile with the ECG of patients with anteroseptal and midseptal accessory pathways.
  
  
  BACKGROUND
  Electrophysiologic findings suggest fasciculoventricular pathways insert into the septal region. Findings also suggest the 12-lead surface ECG during sinus rhythm is similar to the ECG of patients with anteroseptal and midseptal bypass tracts.
  
  
  METHODS
  Four different observers analyzed the 12-lead ECG of seven patients with fasciculoventricular pathways (group I) and the ECG of 20 patients with midseptal AV accessory pathways (group II) and 20 patients with anteroseptal AV accessory pathways (group III). The following variables were analyzed: ECG frontal plane QRS and delta wave axis; angle between the QRS and the delta wave axis; QRS width; R/S ratio in lead III; presence of a negative delta wave in inferior leads; and precordial lead transition to R/S >1.
  
  
  RESULTS
  The ECG of fasciculoventricular pathways shows a variable pattern. It shares some features with an anteroseptal accessory pathway and others with a midseptal accessory pathway. A narrower QRS width was the most important variable in distinguishing a fasciculoventricular pathway from a septally located AV bypass tract (P <.0001). The angle between the QRS and the delta wave frontal plane axis could differentiate a fasciculoventricular pathway from an anteroseptal bypass tract (P <.0001) but not from a midseptal accessory pathway.
  
  
  CONCLUSIONS
  The sinus rhythm ECG of patients with fasciculoventricular pathways shows similarities with ECGs of patients with anteroseptal and midseptal accessory pathways, but the QRS complex usually is narrower. The ECG recorded during sinus rhythm cannot reliably differentiate fasciculoventricular pathways with a broad QRS complex from anteroseptal or midseptal bypass tracts.
authors.affiliation: Department of Arrhythmia and Electrophysiology, Biocor Instituto, Nova Lima, Brazil. eduardosternick@aol.com
authors.forename: Eduardo Back
authors.initials: EB
authors.lastname: Sternick
authors.forename: Luz-Maria
authors.initials: LM
authors.lastname: Rodriguez
authors.forename: Luiz M
authors.initials: LM
authors.lastname: Gerken
authors.forename: Hein J J
authors.initials: HJ
authors.lastname: Wellens
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011226:Pre-Excitation Syndromes / Q000175:diagnosis* / Q000503:physiopathology; D014927:Wolff-Parkinson-White Syndrome / Q000503:physiopathology