title: When deriving the spatial QRS-T angle from the 12-lead electrocardiogram, which transform is more Frank: regression or inverse Dower?
abstract: BACKGROUND
  Our primary objective was to ascertain which commonly used 12-to-Frank-lead transformation yields spatial QRS-T angle values closest to those obtained from simultaneously collected true Frank-lead recordings.
  
  
  METHODS
  Simultaneous 12-lead and Frank XYZ-lead recordings were analyzed for 100 postmyocardial infarction patients and 50 controls. Relative agreement, with true Frank-lead results, of 12-to-Frank-lead-transformed results for the spatial QRS-T angle using Kors' regression versus inverse Dower was assessed via analysis of variance, Lin's concordance, and Bland-Altman plots.
  
  
  RESULTS
  Spatial QRS-T angles from the true Frank leads were not significantly different than those derived from the Kors' regression-related transformation but were significantly smaller than those derived from the inverse Dower-related transformation (P < .001). Independent of method, spatial mean QRS-T angles were also always significantly larger than spatial "maximum" ("peaks") QRS-T angles.
  
  
  CONCLUSIONS
  Spatial QRS-T angles are best approximated by regression-related transforms. Spatial mean and spatial "peaks" QRS-T angles should not be used interchangeably.
authors.affiliation: University of Illinois College of Medicine, Champaign and Rockford, IL, USA.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Cortez
authors.forename: Todd T
authors.initials: TT
authors.lastname: Schlegel
mesh_terms: D000465:Algorithms; D001145:Arrhythmias, Cardiac / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity