TY - JOUR

T1 - The spatial QRS-T angle in the Frank vectorcardiogram

T2 - accuracy of estimates derived from the 12-lead electrocardiogram

AU - Schreurs, Charlotte A.

AU - Algra, Annemijn M.

AU - Man, Sum Che

AU - Cannegieter, Suzanne C.

AU - van der Wall, Ernst E.

AU - Schalij, Martin J.

AU - Kors, Jan A.

AU - Swenne, Cees A.

PY - 2010/7/1

Y1 - 2010/7/1

N2 - Background and Purpose: The spatial QRS-T angle (SA), a predictor of sudden cardiac death, is a vectorcardiographic variable. Gold standard vertorcardiograms (VCGs) are recorded by using the Frank electrode positions. However, with the commonly available 12-lead ECG, VCGs must be synthesized by matrix multiplication (inverse Dower matrix/Kors matrix). Alternatively, Rautaharju proposed a method to calculate SA directly from the 12-lead ECG. Neither spatial angles computed by using the inverse Dower matrix (SA-D) nor by using the Kors matrix (SA-K) or by using Rautaharju's method (SA-R) have been validated with regard to the spatial angles as directly measured in the Frank VCG (SA-F). Our present study aimed to perform this essential validation. Methods: We analyzed SAs in 1220 simultaneously recorded 12-lead ECGs and VCGs, in all data, in SA-F-based tertiles, and after stratification according to pathology or sex. Results: Linear regression of SA-K, SA-D, and SA-R on SA-F yielded offsets of 0.01°, 20.3°, and 28.3° and slopes of 0.96, 0.86, and 0.79, respectively. The bias of SA-K with respect to SA-F (mean ± SD, -3.2° ± 13.9°) was significantly (P < .001) smaller than the bias of both SA-D and SA-R with respect to SA-F (8.0° ± 18.6° and 9.8° ± 24.6°, respectively); tertile analysis showed a much more homogeneous behavior of the bias in SA-K than of both the bias in SA-D and in SA-R. In pathologic ECGs, there was no significant bias in SA-K; bias in men and women did not differ. Conclusion: SA-K resembled SA-F best. In general, when there is no specific reason either to synthesize VCGs with the inverse Dower matrix or to calculate the spatial QRS-T angle with Rautaharju's method, it seems prudent to use the Kors matrix.

AB - Background and Purpose: The spatial QRS-T angle (SA), a predictor of sudden cardiac death, is a vectorcardiographic variable. Gold standard vertorcardiograms (VCGs) are recorded by using the Frank electrode positions. However, with the commonly available 12-lead ECG, VCGs must be synthesized by matrix multiplication (inverse Dower matrix/Kors matrix). Alternatively, Rautaharju proposed a method to calculate SA directly from the 12-lead ECG. Neither spatial angles computed by using the inverse Dower matrix (SA-D) nor by using the Kors matrix (SA-K) or by using Rautaharju's method (SA-R) have been validated with regard to the spatial angles as directly measured in the Frank VCG (SA-F). Our present study aimed to perform this essential validation. Methods: We analyzed SAs in 1220 simultaneously recorded 12-lead ECGs and VCGs, in all data, in SA-F-based tertiles, and after stratification according to pathology or sex. Results: Linear regression of SA-K, SA-D, and SA-R on SA-F yielded offsets of 0.01°, 20.3°, and 28.3° and slopes of 0.96, 0.86, and 0.79, respectively. The bias of SA-K with respect to SA-F (mean ± SD, -3.2° ± 13.9°) was significantly (P < .001) smaller than the bias of both SA-D and SA-R with respect to SA-F (8.0° ± 18.6° and 9.8° ± 24.6°, respectively); tertile analysis showed a much more homogeneous behavior of the bias in SA-K than of both the bias in SA-D and in SA-R. In pathologic ECGs, there was no significant bias in SA-K; bias in men and women did not differ. Conclusion: SA-K resembled SA-F best. In general, when there is no specific reason either to synthesize VCGs with the inverse Dower matrix or to calculate the spatial QRS-T angle with Rautaharju's method, it seems prudent to use the Kors matrix.

UR - http://www.scopus.com/inward/record.url?scp=77953612324&partnerID=8YFLogxK

U2 - 10.1016/j.jelectrocard.2010.03.009

DO - 10.1016/j.jelectrocard.2010.03.009

M3 - Article

C2 - 20417936

AN - SCOPUS:77953612324

VL - 43

SP - 294

EP - 301

JO - Journal of Electrocardiology

JF - Journal of Electrocardiology

SN - 0022-0736

IS - 4

ER -