title: Should all individuals with a nondiagnostic Brugada-electrocardiogram undergo sodium-channel blocker test?
abstract: BACKGROUND
  The diagnostic Brugada-electrocardiogram (Br-ECG) is characterized by "coved-type" ST-segment elevation (type 1) in V(1) to V(2)/V(3). The sodium-channel blocker test is clinically used to unmask diagnostic Br-ECG in patients with nondiagnostic "saddle-back" Br-ECG (type 2 and type 3).
  
  
  OBJECTIVE
  To assess the prognostic value of the sodium-channel blockers test in individuals with a nondiagnostic Br-ECG.
  
  
  METHODS
  We studied 153 consecutive patients (128 men; age 41.7 ± 14.0 years) with a type 2/3 Br-ECG who underwent a sodium-channel blocker test with either flecainide (48%) or ajmaline (52%). Nondiagnostic Br-ECGs were identified during the evaluation of cardiac arrest in 5 patients (3%), syncope in 36 (24%), cascade family screening in 48 (31%), and incidental ECG in 64 (42%). A spontaneous type 1 Br-ECG was systematically excluded by serial ECGs (6.1 ± 0.4) and recording of right precordial leads both at standard and second and third intercostal spaces.
  
  
  RESULTS
  The sodium-channel blocker test result was positive in 76 (50%) patients. During a follow-up of 59 ± 33 months, 9 (5.9%) patients experienced events such as syncope (n = 4), appropriate interventions of defibrillator (n = 4), or sudden death (n = 1). A positive sodium-channel blocker test was associated with a significantly higher event rate in symptomatic patients (P = .01) but not in asymptomatic individuals (P = .18). No events occurred among asymptomatic individuals with an incidental nondiagnostic Br-ECG.
  
  
  CONCLUSIONS
  In asymptomatic individuals with a nondiagnostic Br-ECG, the incidence of events is low regardless of the sodium-channel blocker test result while in symptomatic patients a positive sodium-channel blocker test result is associated with an adverse arrhythmic outcome and may contribute to risk stratification.
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Zorzi
authors.forename: Federico
authors.initials: F
authors.lastname: Migliore
authors.forename: Elena
authors.initials: E
authors.lastname: Marras
authors.forename: Alessio
authors.initials: A
authors.lastname: Marinelli
authors.forename: Anna
authors.initials: A
authors.lastname: Baritussio
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Allocca
authors.forename: Loira
authors.initials: L
authors.lastname: Leoni
authors.forename: Martina
authors.initials: M
authors.lastname: Perazzolo Marra
authors.forename: Cristina
authors.initials: C
authors.lastname: Basso
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Buja
authors.forename: Gaetano
authors.initials: G
authors.lastname: Thiene
authors.forename: Sabino
authors.initials: S
authors.lastname: Iliceto
authors.forename: Pietro
authors.initials: P
authors.lastname: Delise
authors.forename: Domenico
authors.initials: D
authors.lastname: Corrado
mesh_terms: D000328:Adult; D000404:Ajmaline / Q000008:administration & dosage; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage; D053840:Brugada Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control* / Q000639:trends; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000187:drug effects / Q000379:methods*; D005080:Exercise Test / Q000379:methods; D005260:Female; D005424:Flecainide / Q000008:administration & dosage; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007262:Infusions, Intravenous; D007558:Italy / Q000453:epidemiology; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods*; D026941:Sodium Channel Blockers / Q000008:administration & dosage; D013997:Time Factors
chemical_list: D000889:Anti-Arrhythmia Agents; D026941:Sodium Channel Blockers; D000404:Ajmaline; D005424:Flecainide