title: Body surface area of ST elevation and the presence of late potentials correlate to the inducibility of ventricular tachyarrhythmias in Brugada syndrome.
abstract: BACKGROUND
  The value of noninvasive markers reflecting repolarization and/or conduction abnormalities in identifying patients with abnormal ECG showing a pattern of atypical right bundle branch block and ST elevation syndrome (Brugada syndrome) at risk for life-threatening arrhythmias is controversial. Because right precordial ST elevation reflects inhomogeneous repolarization, we hypothesized that a correlation between the area of ST elevation, that is, the area of inhomogeneous repolarization, and the inducibility of ventricular tachyarrhythmias (VT) exists. Therefore, the body surface area of ST elevation and the presence of late potentials were compared to the inducibility of VT in patients with the characteristic ECG of Brugada syndrome.
  
  
  RESULTS
  A 120-channel body surface potential map was recorded at rest and after administration of a Class I agent (ajmaline, 1 mg/kg) to measure the body surface area of ST elevation (> or = 0.2 mV) in 23 individuals (16 patients had been resuscitated from near sudden cardiac death or had suffered syncope) with an ECG compatible with the diagnosis of Brugada syndrome as well as in 15 healthy controls and in 15 patients with arrhythmogenic right ventricular cardiomyopathy. Late potentials were assessed in 20 of the Brugada patients using signal-averaged ECG. Programmed ventricular stimulation was performed at two ventricular sites with up to three extrastimuli. Mean body surface area of ST elevation (> or = 0.2 mV) of all Brugada syndrome patients was 154 +/- 139 cm2 (control 9 +/- 9 cm2; P < 0.001). In the group of patients with arrhythmogenic right ventricular cardiomyopathy, only one patient was found to have an area of ST elevation (165 cm2). In the presence of ajmaline, area size increased to 330 +/- 223 cm2 in Brugada syndrome patients (P < 0.05). In patients with inducible sustained (n = 15) and nonsustained VT (n = 3), a mean area of 183 +/- 139 cm2 was found, whereas the area was only 52 +/- 58 cm2 in those with no VT induction (P < 0.05). For an area > or = 50 cm2, there were positive and negative predictive values of 92% and 60%, respectively. Positive late potentials were found in 60% of patients and correlated to the inducibility during programmed ventricular stimulation (positive predictive value 100%, negative predictive value 75%; P < 0.001).
  
  
  CONCLUSIONS
  In patients with Brugada syndrome, the body surface area of ST elevation and the presence of late potentials correlate to the inducibility of VT during programmed ventricular stimulation and may be of value as a new noninvasive marker for risk stratification in these patients.
authors.affiliation: Hospital of the Westfälischen Wilhelms-University, Department of Cardiology and Angiology and Institute for Arteriosclerosis Research, Münster, Germany. l.eckardt@uni-muenster.de
authors.forename: Lars
authors.initials: L
authors.lastname: Eckardt
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Bruns
authors.forename: Matthias
authors.initials: M
authors.lastname: Paul
authors.forename: Paulus
authors.initials: P
authors.lastname: Kirchhof
authors.forename: Eric
authors.initials: E
authors.lastname: Schulze-Bahr
authors.forename: Thomas
authors.initials: T
authors.lastname: Wichter
authors.forename: Günter
authors.initials: G
authors.lastname: Breithardt
authors.forename: Martin
authors.initials: M
authors.lastname: Borggrefe
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Haverkamp
mesh_terms: D000328:Adult; D000368:Aged; D001830:Body Surface Area; D018780:Body Surface Potential Mapping; D002037:Bundle-Branch Block / Q000150:complications* / Q000175:diagnosis* / Q000628:therapy; D015331:Cohort Studies; D017147:Defibrillators, Implantable; D004558:Electric Stimulation; D022062:Electrophysiologic Techniques, Cardiac; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D013577:Syndrome; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology* / Q000628:therapy; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000209:etiology / Q000628:therapy