title: Diagnostic value of programmed ventricular stimulation in patients with bifascicular block: a prospective study of patients with and without syncope.
abstract: OBJECTIVE
  The aim of this study was to examine the inducibility of ventricular arrhythmias in patients with bifascicular block both with and without a history of syncope and to relate the findings to clinical events during follow-up.
  
  
  BACKGROUND
  Patients with bifascicular block have an increased risk of sudden death that is not reduced by pacemaker treatment. This risk could be related to a high incidence of ventricular arrhythmias.
  
  
  METHODS
  Programmed ventricular stimulation was performed in 101 patients with bifascicular block: 41 had a history of unexplained syncope, and 60 were asymptomatic.
  
  
  RESULTS
  Programmed ventricular stimulation resulted in a sustained ventricular arrhythmia in 18 patients (18%), 8 in the syncope group and 10 in the nonsyncope group (p = NS). Three patients in each group had an inducible sustained monomorphic ventricular tachycardia. During a mean follow-up of 21 months, 10 patients experienced a clinical event defined as sudden death (n = 4), syncope (n = 5) or appropriate discharges from an implantable cardioverter-defibrillator (n = 1). Only one of these patients had an inducible ventricular arrhythmia at baseline.
  
  
  CONCLUSIONS
  The inducibility of ventricular arrhythmias is high in patients with bifascicular block and of the same magnitude in patients with and without a history of syncope. Clinical events during follow-up were not predicted by programmed ventricular stimulation in either of the two groups. The finding of inducible ventricular arrhythmia in patients with bifascicular block should therefore be interpreted with caution.
authors.affiliation: Department of Cardiology, Karolinska Hospital, Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Englund
authors.forename: L
authors.initials: L
authors.lastname: Bergfeldt
authors.forename: N
authors.initials: N
authors.lastname: Rehnqvist
authors.forename: H
authors.initials: H
authors.lastname: Aström
authors.forename: M
authors.initials: M
authors.lastname: Rosenqvist
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial; D005260:Female; D006327:Heart Block / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013575:Syncope / Q000209:etiology*