title: Do patients with electrocardiographic Brugada type 1 pattern have associated right bundle branch block? A comparative vectorcardiographic study.
abstract: OBJECTIVE
  Previous studies have reported right bundle branch block in Brugada syndrome. Subsequent analysis of electrocardiograms (ECGs) found one-third of cases classified as right bundle branch block did not meet criteria of a wide final S wave in the left leads. We aimed to study the role of the vectorcardiogram to characterize Brugada type 1 ECG pattern.
  
  
  RESULTS
  Compare Frank-method vectorcardiogram in 11 patients with Brugada type 1 ECG pattern (BrS group) with vectorcardiogram of 20 healthy individuals with ECGs depicting incomplete right bundle branch block (IRBBB group) and 12 patients with complete right bundle branch block (CRBBB group). Initial 10-20 ms vector of the QRS loop in the horizontal plane (HP): BrS and IRBBB groups: Vector heading anterior and leftward. CRBBB group: Vector directed anterior and rightward. Right end conduction delay of the QRS loop: BrS group: Upper right quadrant of the frontal plane, right posterior quadrant of the HP. IRBBB group: Upper right quadrant of the frontal plane (30%) and right anterior quadrant of the HP (90%). CRBBB group: Upper right quadrant on the frontal plane (30%); all cases in the right anterior quadrant of the HP. 0 point (onset of QRS loop) and J point (end of QRS loop) relationship: BrS group: Not coincidental. IRBBB and CRBBB groups: Coincidental. T loop morphology, size, and appearance: BrS group: Circular, with symmetrical afferent and efferent limbs in 10 cases (90%). IRBBB and CRBBB groups: Elliptical or linear with slow inscription of efferent limb and rapid inscription of afferent limb.
  
  
  CONCLUSIONS
  Vectorcardiograms in patients with Brugada type 1 ECG pattern have distinctive characteristics compared with healthy individuals with incomplete and CRBBB. These differences relate to the spatial location of the end conduction delay (right superior and posterior quadrant in the BrS group) and the morphology, size, and velocity of inscription of afferent and efferent limbs of the T loop (circular, small, of symmetrical limbs) and with a 1:1 length/width ratio.
authors.affiliation: Faculdade de Medicina do ABC Fundação do ABC, Santo André, Rua Sebastião Afonso, 885-CEP 04417-000 Jardim Miriam, São Paulo, Brazil. luisferreirasantos@gmail.com
authors.forename: Andrés R
authors.initials: AR
authors.lastname: Peréz-Riera
authors.forename: Celso
authors.initials: C
authors.lastname: Ferreira Filho
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: de Abreu
authors.forename: Celso
authors.initials: C
authors.lastname: Ferreira
authors.forename: Frank G
authors.initials: FG
authors.lastname: Yanowitz
authors.forename: Francisco
authors.initials: F
authors.lastname: Femenia
authors.forename: Pedro
authors.initials: P
authors.lastname: Brugada
authors.forename: Adrian
authors.initials: A
authors.lastname: Baranchuk
mesh_terms: D000328:Adult; D053840:Brugada Syndrome / Q000150:complications* / Q000175:diagnosis* / Q000503:physiopathology; D002037:Bundle-Branch Block / Q000150:complications* / Q000175:diagnosis* / Q000503:physiopathology; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013575:Syncope / Q000175:diagnosis / Q000209:etiology; D014672:Vectorcardiography / Q000379:methods*