title: Predictors of advanced His-Purkinje conduction disturbances in patients with unexplained syncope and bundle branch block.
abstract: BACKGROUND
  For patients presenting with syncope and bundle branch block (BBB), results during electrophysiological studies (EPS) might depend on the electrocardiographic pattern of conduction disturbances. We sought to identify predictors of advanced His-Purkinje conduction disturbances (HPCDs) in these patients.
  
  
  METHODS
  In this retrospective multicentre study, patients were included who: (1) presented with unexplained syncope; (2) had BBB (QRS duration ≥ 120 ms); and (3) were investigated with EPS. HPCD was diagnosed if the baseline His-ventricular interval was ≥ 70 ms or if second- or third-degree His-Purkinje block was observed during atrial pacing or pharmacological challenge.
  
  
  RESULTS
  Of the 171 patients studied (72 ± 13 years, 64% male sex, mean left ventricular ejection fraction 57 ± 9%), advanced HPCD was found in 73 patients (43%). The following electrocardiographic features were associated with HPCD (P = 0.01): isolated right BBB (34.4%), right BBB with left anterior fascicular block (36.4%), left BBB (46.2%), and right BBB with left posterior fascicular block (LPFB, 78.6%). Multivariate analysis identified first-degree atrioventricular block (odds ratio, 2.4; 95% confidence interval, 1.2-4.7; P = 0.01) and LPFB (odds ratio, 4.8; 95% confidence interval, 1.3-18.5; P = 0.02) as the only 2 independent predictors of advanced HPCD.
  
  
  CONCLUSIONS
  For patients presenting with syncope and BBB, first-degree atrioventricular block and LPFB increased the likelihood of finding HPCDs during EPS. However, no single electrocardiographic feature could consistently predict the outcome of EPS, so this investigation is still necessary in assessing the need for pacemaker implantation, irrespective of the precise appearance of abnormalities on ECG.
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France. Electronic address: stephane.boule@chru-lille.fr.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Boulé
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France; Arras Regional Hospital, Department of Cardiovascular Medicine, Arras, France.
authors.forename: Aïcha
authors.initials: A
authors.lastname: Ouadah
authors.affiliation: University of Lille 2, Biostatistics Unit, Lille, France.
authors.forename: Carole
authors.initials: C
authors.lastname: Langlois
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Botcherby
authors.affiliation: Duchenne Hospital, Department of Cardiovascular Medicine, Boulogne sur Mer, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Verbrugge
authors.affiliation: Schaffner Hospital, Department of Cardiovascular Medicine, Lens, France.
authors.forename: David
authors.initials: D
authors.lastname: Huchette
authors.affiliation: University of Lille 2, Biostatistics Unit, Lille, France.
authors.forename: Julia
authors.initials: J
authors.lastname: Salleron
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France.
authors.forename: Meriem
authors.initials: M
authors.lastname: Mostefa Kara
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Kouakam
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France.
authors.forename: François
authors.initials: F
authors.lastname: Brigadeau
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France; University of Lille 2, Faculty of Medicine, Lille, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Klug
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Marquié
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Guédon-Moreau
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France; University of Lille 2, Faculty of Medicine, Lille, France.
authors.forename: Ludivine
authors.initials: L
authors.lastname: Wissocque
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France; University of Lille 2, Faculty of Medicine, Lille, France.
authors.forename: William
authors.initials: W
authors.lastname: Escande
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France; University of Lille 2, Faculty of Medicine, Lille, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Lacroix
authors.affiliation: Lille University Hospital, Department of Cardiovascular Medicine, Lille, France; University of Lille 2, Faculty of Medicine, Lille, France.
authors.forename: Salem
authors.initials: S
authors.lastname: Kacet
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000145:classification / Q000503:physiopathology / Q000601:surgery; D002036:Bundle of His / Q000503:physiopathology*; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D010138:Pacemaker, Artificial; D011690:Purkinje Fibers / Q000503:physiopathology*; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology; D013575:Syncope / Q000503:physiopathology*