When deriving the spatial QRS-T angle from the 12-lead electrocardiogram, which transform is more Frank: regression or inverse Dower?

Abstract 

Introduction

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.

Materials and 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.

Discussion

Spatial QRS-T angles are best approximated by regression-related transforms. Spatial mean and spatial “peaks” QRS-T angles should not be used interchangeably.

Keywords: Vectorcardiography, Spatial ventricular gradient, 3-Dimensional ECG, Lead reconstruction