title: Prevention of ventricular fibrillation episodes in Brugada syndrome by catheter ablation over the anterior right ventricular outflow tract epicardium.
abstract: BACKGROUND
  The underlying electrophysiological mechanism that causes an abnormal ECG pattern and ventricular tachycardia/ventricular fibrillation (Vt/VF) in patients with the Brugada syndrome (BrS) remains unelucidated. However, several studies have indicated that the right ventricular outflow tract (RVOT) is likely to be the site of electrophysiological substrate. We hypothesized that in patients with BrS who have frequent recurrent VF episodes, the substrate site is the RVOT, either over the epicardium or endocardium; abnormal electrograms would be identified at this location, which would serve as the target site for catheter ablation.
  
  
  RESULTS
  We studied 9 symptomatic patients with the BrS (all men; median age 38 years) who had recurrent VF episodes (median 4 episodes) per month, necessitating implantable cardioverter defibrillator discharge. Electroanatomic mapping of the right ventricle, both endocardially and epicardially, and epicardial mapping of the left ventricle were performed in all patients during sinus rhythm. All patients had typical type 1 Brugada ECG pattern and inducible Vt/VF; they were found to have unique abnormal low voltage (0.94±0.79 mV), prolonged duration (132±48 ms), and fractionated late potentials (96±47 ms beyond QRS complex) clustering exclusively in the anterior aspect of the RVOT epicardium. Ablation at these sites rendered Vt/VF noninducible (7 of 9 patients [78%]; 95% confidence interval, 0.40 to 0.97, P=0.015) and normalization of the Brugada ECG pattern in 89% (95% confidence interval, 0.52 to 0.99; P=0.008). Long-term outcomes (20±6 months) were excellent, with no recurrent Vt/VF in all patients off medication (except 1 patient on amiodarone).
  
  
  CONCLUSIONS
  The underlying electrophysiological mechanism in patients with BrS is delayed depolarization over the anterior aspect of the RVOT epicardium. Catheter ablation over this abnormal area results in normalization of the Brugada ECG pattern and prevents Vt/VF, both during electrophysiological studies as well as spontaneous recurrent Vt/VF episodes in patients with BrS.
authors.affiliation: Pacific Rim Electrophysiology Research Institute, 1700 Cesar E. Chavez Avenue, Los Angeles, CA 90033, USA. wee@pacificrimep.com
authors.forename: Koonlawee
authors.initials: K
authors.lastname: Nademanee
authors.forename: Gumpanart
authors.initials: G
authors.lastname: Veerakul
authors.forename: Pakorn
authors.initials: P
authors.lastname: Chandanamattha
authors.forename: Lertlak
authors.initials: L
authors.lastname: Chaothawee
authors.forename: Aekarach
authors.initials: A
authors.lastname: Ariyachaipanich
authors.forename: Kriengkrai
authors.initials: K
authors.lastname: Jirasirirojanakorn
authors.forename: Khanchit
authors.initials: K
authors.lastname: Likittanasombat
authors.forename: Kiertijai
authors.initials: K
authors.lastname: Bhuripanyo
authors.forename: Tachapong
authors.initials: T
authors.lastname: Ngarmukos
mesh_terms: D000328:Adult; D053840:Brugada Syndrome / Q000150:complications* / Q000175:diagnosis / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D017147:Defibrillators, Implantable; D022062:Electrophysiologic Techniques, Cardiac; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium; D011446:Prospective Studies; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000209:etiology* / Q000517:prevention & control* / Q000628:therapy; D055815:Young Adult