title: T wave alternans does not assess arrhythmic risk in patients with Brugada syndrome.
abstract: BACKGROUND
  Brugada syndrome is associated with a risk for sudden death, but the arrhythmic risk in an individual Brugada syndrome patient is difficult to predict. Pathologic changes in the early repolarization phase of the ventricular action potential probably constitute part of the arrhythmogenic substrate in Brugada syndrome. Microvolt T wave alternans (TWA) assesses dynamic beat-to-beat changes in repolarization and has been suggested as a marker for repolarization-related sudden death. We therefore tested whether TWA is an indicator for arrhythmias in Brugada syndrome with a focus on right precordial ECG leads.
  
  
  METHODS
  We assessed TWA in nine symptomatic, inducible patients with established Brugada syndrome and in seven healthy controls. TWA was assessed at rest and during exercise using both standard methods and an algorithm that assesses TWA in the early ST segment and the right precordial leads.
  
  
  RESULTS
  None of the Brugada patients developed TWA in this study irrespective of analysis at rest or during exercise, neither using standard methods nor when the early ST segment was included in the analysis. When the early ST segment was included in the analysis, nonsustained TWA was found in three out of seven, and sustained TWA in one control.
  
  
  CONCLUSIONS
  T wave alternans is not an appropriate test to detect arrhythmic risk in patients with Brugada syndrome.
authors.affiliation: Department of Cardiology and Angiology, University Hospital Münster, Institute of Arteriosclerosis Research at the University of Münster, Germany. kirchhp@uni-muenster.de
authors.forename: Paulus
authors.initials: P
authors.lastname: Kirchhof
authors.forename: Lars
authors.initials: L
authors.lastname: Eckardt
authors.forename: Sascha
authors.initials: S
authors.lastname: Rolf
authors.forename: Hans-D
authors.initials: HD
authors.lastname: Esperer
authors.forename: Matthias
authors.initials: M
authors.lastname: Paul
authors.forename: Thomas
authors.initials: T
authors.lastname: Wichter
authors.forename: Helmut U
authors.initials: HU
authors.lastname: Klein
authors.forename: Günter
authors.initials: G
authors.lastname: Breithardt
authors.forename: Dirk
authors.initials: D
authors.lastname: Böcker
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000628:therapy; D002037:Bundle-Branch Block / Q000453:epidemiology* / Q000628:therapy; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013575:Syncope / Q000453:epidemiology / Q000209:etiology; D016896:Treatment Outcome