title: Effect of sodium-channel blockade on early repolarization in inferior/lateral leads in patients with idiopathic ventricular fibrillation and Brugada syndrome.
abstract: BACKGROUND
  A high incidence of early repolarization (ER) pattern in the inferolateral leads has been reported in patients with idiopathic ventricular fibrillation (IVF). Brugada syndrome (BS) is characterized by J-point or ST-segment elevation in the right precordial leads and ventricular fibrillation, and some patients with BS also have ER in the inferolateral leads.
  
  
  OBJECTIVE
  To compare the clinical characteristics and effects of sodium-channel blockade on ER between IVF patients with ER (early repolarization syndrome [ERS]) and BS patients with or without ER.
  
  
  METHODS
  Fourteen patients with ERS and 21 patients with BS were included in this study. ER was defined as an elevation of at least 0.1 mV from baseline in the QRS-T junction in the inferorolateral leads. Provocative tests with sodium-channel blockers were conducted in all patients with ERS to distinguish ERS from BS.
  
  
  RESULTS
  In the ERS group, all patients were male and most patients experienced ventricular fibrillation during sleep or low activity (79%). ER was attenuated by sodium-channel blockers in most patients with ERS (13/14, 93%) and BS (5/5, 100%), whereas ST-segment elevation was augmented in the right precordial leads in the BS group. The rates of positive late potentials were significantly higher in the BS group (60%) than in the ERS group (7%) (P <.01).
  
  
  CONCLUSIONS
  Some similarities were observed between ERS and BS, including gender, arrhythmia triggers, and response of ER to sodium-channel blockers. Unlike the ST segment in the right precordial leads in BS, ER was attenuated in patients with both ERS and BS, suggesting a differential mechanism between ER in the inferolateral leads and ST elevation in the right precordial leads.
authors.affiliation: Division of Arrhythmia and Electrophysiology, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan.
authors.forename: Hiro
authors.initials: H
authors.lastname: Kawata
authors.forename: Takashi
authors.initials: T
authors.lastname: Noda
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yamada
authors.forename: Hideo
authors.initials: H
authors.lastname: Okamura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Satomi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Aiba
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takaki
authors.forename: Naohiko
authors.initials: N
authors.lastname: Aihara
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
authors.forename: Shiro
authors.initials: S
authors.lastname: Kamakura
authors.forename: Wataru
authors.initials: W
authors.lastname: Shimizu
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000188:drug therapy* / Q000503:physiopathology; D053840:Brugada Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D004562:Electrocardiography / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D026941:Sodium Channel Blockers / Q000494:pharmacology* / Q000627:therapeutic use; D014693:Ventricular Fibrillation / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D026941:Sodium Channel Blockers