title: Role of electrophysiological study in patients with syncope and bundle branch block.
abstract: BACKGROUND
  The finding of bundle branch block (BBB) in patients with syncope suggests that paroxysmal atrioventricular block (AVB) or ventricular tachyarrhythmia (VT) may be the cause of syncope. Guidelines for cardiac pacing and cardiac resynchronization therapy have been recommended to perform electrophysiological study (EPS) for confirming main cause of syncope. Therefore, the aim of our study was to evaluate the role of EPS in patients with syncope and BBB.
  
  
  METHODS
  We evaluated 133 patients (mean age 63 ± 13.8 years) with past history of syncope and BBB from April 2002 to December 2010 who referred to Arrhythmia clinic in two tertiary care centers. All patients underwent EPS on admission time. The frequency distributions of AVB and VT in patients were determined.
  
  
  RESULTS
  Left bundle branch block was diagnosed in 184 (82.1%) patients. 133 of them had preserved left ventricular ejection fraction (LVEF ≥45%) that in 91 (68.4%) of those, EPS finding was normal. In 41 (30.8%) patients AVB was reported. In 2 (1.5%) patients VT and atrioventricular nodal reentrant tachycardia were seen. Coronary artery disease was more common in patients with AVB and abnormal EPS finding (P = 0.02).
  
  
  CONCLUSIONS
  Ventricular tachyarrhythmia was a rare electrophysiological finding in those with syncope, bifascicular block, and preserved LVEF. Considering cost-effect benefit, pacemaker or implantable loop recorder implantation is suggested; however, EPS may not be necessary to perform before permanent pacemaker implantation.
authors.affiliation: Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Neshat
authors.initials: N
authors.lastname: Nazari
authors.affiliation: Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Ala
authors.initials: A
authors.lastname: Keykhavani
authors.affiliation: Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Sima
authors.initials: S
authors.lastname: Sayah
authors.affiliation: Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Hekmat
authors.affiliation: Shahid Beheshti Hospital, Kashan University of Medical Sciences, Kashan, Iran.
authors.forename: Allahyar
authors.initials: A
authors.lastname: Golabchi
authors.affiliation: Cardiac Electrophysiology Research Center, Heshmat Cardiovascular Medical and Research Center, Guilan University of Medical Sciences, Rasht, Iran.
authors.forename: Mohammad Assadian
authors.initials: MA
authors.lastname: Rad
authors.affiliation: Cardiac Electrophysiology Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Abolfath
authors.initials: A
authors.lastname: Alizadeh
authors.affiliation: Cardiac Electrophysiology Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mona
authors.initials: M
authors.lastname: Heidarali
keywords: Atrioventricular block; electrophysiological study; left bundle branch block; permanent pacemaker implantation; syncope; ventricular tachyarrhythmia