title: Differential diagnosis of wide QRS tachycardias: comparison of two electrocardiographic algorithms.
abstract: OBJECTIVE
  This study's aim is to compare the ability of two ECG criteria to differentiate ventricular (VT) from supraventricular tachycardia (SVT): Brugada et al. [horizontal plane (HP) leads] and Vereckei et al. [frontal plane (FP), specifically aVR lead], having electrophysiological study (EPS) as gold standard. After comparing, suggestions for better diagnosis of wide QRS-complex tachycardia (WCT) in emergency situations were made.
  
  
  RESULTS
  Fifty-one consecutive patients with 12-lead ECG registered during EPS-induced regular WCT were selected. Each ECG was split into two parts: HP (V1-V6) and FP (D1-D3, aVR, aVL, and aVF), randomly distributed to three observers, blinded for EPS diagnosis and complementary ECG plane, resulting in total 306 ECG analyses. Observers followed the four steps of both algorithms, counting time-to-diagnosis. Global sensitivity, specificity, percentage of incorrect diagnoses, and step-by-step positive/negative likelihood ratios (+LR and -LR) were calculated. Kaplan-Meier curve was plotted for final time-to-diagnosis. Inter-observer agreement was assessed with kappa-statistic. Global sensitivity was similarly high in FP and HP algorithms (89.2 vs. 90.1%), and incorrect classifications were 27.4 vs. 24.7%. Forty-eight correct analyses by Vereckei criteria took 9.13 s to diagnose VT in the first step, showing that first step was fast, with high +LR, generating nearly conclusive pre- (72.6%) to post-test (98.0%) changes for VT probability.
  
  
  CONCLUSIONS
  Both algorithms as a whole are similar for diagnosis of WTC; however, the first step of Vereckei (initial R in aVR) is a simple, reproducible, accurate, and fast tool to use. The negativity of this step requires a 'holistic' approach to distinguish VT from SVT.
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil kaiser.zsoci@gmail.com.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kaiser
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Francisco C C
authors.initials: FC
authors.lastname: Darrieux
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Silvio A
authors.initials: SA
authors.lastname: Barbosa
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Grinberg
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Andre
authors.initials: A
authors.lastname: Assis-Carmo
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Julio C
authors.initials: JC
authors.lastname: Sousa
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Denise
authors.initials: D
authors.lastname: Hachul
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Cristiano F
authors.initials: CF
authors.lastname: Pisani
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Eva
authors.initials: E
authors.lastname: Kosa
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Pastore
authors.affiliation: Arrhythmia Unit-Heart Institute (InCor), University of Sao Paulo Medical School, Av. Dr. Eneas de Carvalho Aguiar, 44, Sao Paulo, SP 04011-060, Brazil.
authors.forename: Mauricio I
authors.initials: MI
authors.lastname: Scanavacca
mesh_terms: D000465:Algorithms; D003937:Diagnosis, Differential; D004562:Electrocardiography; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013617:Tachycardia, Supraventricular / Q000175:diagnosis*; D017180:Tachycardia, Ventricular / Q000175:diagnosis*
keywords: Brugada algorithm; Electrocardiographic diagnosis; Supraventricular tachycardia; Ventricular tachycardia; Vereckei algorithm; Wide QRS tachycardia