title: Endocardial electrograms from the right ventricular outflow tract after induced ventricular fibrillation in patients with Brugada syndrome.
abstract: BACKGROUND
  The pathogenesis of Brugada syndrome (BS) is reported to be phase 2 reentry resulting from shortening of the action potential duration at the epicardial site of the right ventricular outflow tract (RVOT). However, several reports have shown a high incidence of ventricular late potentials (LPs) and a high rate of induction of ventricular fibrillation (VF) by programmed ventricular stimulation (PVS) among patients with BS. The aim of this study was to investigate the role of slow conduction for the initiation of VF by PVS in these patients.
  
  
  RESULTS
  Endocardial mapping of the RVOT was conducted in 17 patients in whom VF was induced by PVS from the RV apex or RVOT; 11 patients had a positive LP. In 10 patients, RV mapping showed that low-amplitude fragmented and delayed potentials (DPs) were recorded at the RVOT below the pulmonary valve (PV) or between the PV and His bundle electrogram recording site. Electrograms recorded after PVS showed a high incidence of fractionated and disorganized DPs that lead to VF.
  
  
  CONCLUSIONS
  Slow conduction at the RVOT may contribute to the induction of VF by PVS. However, the role of slow conduction in spontaneous VF remains controversial.
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Kimie
authors.initials: K
authors.lastname: Ohkubo
authors.forename: Ichiro
authors.initials: I
authors.lastname: Watanabe
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takagi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Okumura
authors.forename: Sonoko
authors.initials: S
authors.lastname: Ashino
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kofune
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kofune
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shindo
authors.forename: Hidezou
authors.initials: H
authors.lastname: Sugimura
authors.forename: Toshiko
authors.initials: T
authors.lastname: Nakai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kunimoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kasamaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saito
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hirayama
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D018780:Body Surface Potential Mapping; D053840:Brugada Syndrome / Q000209:etiology* / Q000503:physiopathology*; D004562:Electrocardiography; D006329:Heart Conduction System; D006801:Humans; D008297:Male; D008875:Middle Aged; D014693:Ventricular Fibrillation / Q000209:etiology / Q000503:physiopathology