title: Unsuccessful internal defibrillation in Brugada syndrome: focus on refractoriness and ventricular fibrillation cycle length.
abstract: BACKGROUND
  In patients with Brugada syndrome, implantable cardioverter defibrillator (ICD) is the only reliable treatment to prevent sudden death though, in some cases, internal defibrillation may be unsuccessful. The aim of this study was to examine the determinants of defibrillation failure, with a focus on electrophysiologic characteristics.
  
  
  METHODS
  The study included 51 patients treated with ICD: 22 with Brugada syndrome and 29 with structural heart disease (SHD). The prevalence of defibrillation energy requirement precluding the programming of a 10-J safety margin, the mean right ventricular effective refractory period (ERP), and mean induced ventricular fibrillation cycle length (VFCL) from the stored ICD electrograms, were compared between the two patient groups.
  
  
  RESULTS
  High defibrillation requirements were observed in 18% of patients with Brugada syndrome versus 0% of patients with SHD. However, the patients with SHD had larger heart size than those with Brugada syndrome. Mean VFCL and mean ERP were both significantly shorter in patients with Brugada syndrome than in patients with SHD, and ERP and VFCL were significantly correlated.
  
  
  CONCLUSIONS
  Patients with Brugada syndrome have a high prevalence of high defibrillation energy requirement, and short ventricular ERP and VFCL.
authors.affiliation: Niigata University Graduate School of Medical and Dental Science, Niigata, Japan. hiroshi7@med.niigata-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Masaomi
authors.initials: M
authors.lastname: Chinushi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sugiura
authors.forename: Takashi
authors.initials: T
authors.lastname: Washizuka
authors.forename: Satoru
authors.initials: S
authors.lastname: Komura
authors.forename: Yukio
authors.initials: Y
authors.lastname: Hosaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Furushima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Junichi
authors.initials: J
authors.lastname: Hayashi
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
mesh_terms: D002037:Bundle-Branch Block / Q000503:physiopathology / Q000628:therapy*; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D013577:Syndrome; D017180:Tachycardia, Ventricular / Q000503:physiopathology / Q000628:therapy*; D017211:Treatment Failure; D014693:Ventricular Fibrillation / Q000503:physiopathology / Q000628:therapy*