title: New methodologies for measuring Brugada ECG patterns cannot differentiate the ECG pattern of Brugada syndrome from Brugada phenocopy.
abstract: BACKGROUND
  Brugada phenocopies (BrP) are clinical entities characterized by ECG patterns that are identical to true Brugada syndrome (BrS), but are elicited by various clinical circumstances. A recent study demonstrated that the patterns of BrP and BrS are indistinguishable under the naked eye, thereby validating the concept that the patterns are identical.
  
  
  OBJECTIVE
  The aim of our study was to determine whether recently developed ECG criteria would allow for discrimination between type-2 BrS ECG pattern and type-2 BrP ECG pattern.
  
  
  METHODS
  Ten ECGs from confirmed BrS (aborted sudden death, transformation into type 1 upon sodium channel blocking test and/or ventricular arrhythmias, positive genetics) cases and 9 ECGs from confirmed BrP were included in the study. Surface 12-lead ECGs were scanned, saved in JPEG format for blind measurement of two values: (i) β-angle; and (ii) the base of the triangle. Cut-off values of ≥58° for the β-angle and ≥4mm for the base of the triangle were used to determine the BrS ECG pattern.
  
  
  RESULTS
  Mean values for the β-angle in leads V1 and V2 were 66.7±25.5 and 55.4±28.1 for BrS and 54.1±26.5 and 43.1±16.1 for BrP respectively (p=NS). Mean values for the base of the triangle in V1 and V2 were 7.5±3.9 and 5.7±3.9 for BrS and 5.6±3.2 and 4.7±2.7 for BrP respectively (p=NS). The β-angle had a sensitivity of 60%, specificity of 78% (LR+ 2.7, LR- 0.5). The base of the triangle had a sensitivity of 80%, specificity of 40% (LR+ 1.4, LR- 0.5).
  
  
  CONCLUSIONS
  New ECG criteria presented relatively low sensitivity and specificity, positive and negative predictive values to discriminate between BrS and BrP ECG patterns, providing further evidence that the two patterns are identical.
authors: Department of Cardiology, Kingston General Hospital, Queen's University, Kingston, ON, Canada.
authors: Byron H
authors: BH
authors: Gottschalk
authors: Servicios Sanitarios del Área de Salud de El Hierro, Valle del Golfo Health Center, Canary Island, Spain.
authors: Javier
authors: J
authors: Garcia-Niebla
authors: Libin Cardiovascular Institute of Alberta, Foothills Medical Centre, University of Calgary, Calgary, AB, Canada.
authors: Daniel D
authors: DD
authors: Anselm
authors: Department of Cardiology, Kingston General Hospital, Queen's University, Kingston, ON, Canada.
authors: Atul
authors: A
authors: Jaidka
authors: Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa CreuiSant Pau, Barcelona, Spain.
authors: Antoni Bayés
authors: AB
authors: De Luna
authors: Department of Cardiology, Kingston General Hospital, Queen's University, Kingston, ON, Canada. Electronic address: barancha@kgh.kari.net.
authors: Adrian
authors: A
authors: Baranchuk
mesh_terms: D000465:Algorithms; D053840:Brugada Syndrome / Q000145:classification / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods*; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Base of triangle; Beta angle; Brugada ECG pattern; Brugada phenocopy; Brugada syndrome; ECG criteria