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A simple procedure for estimation of the spatial QRS/T angle from the standard 12-lead electrocardiogram.

TitleA simple procedure for estimation of the spatial QRS/T angle from the standard 12-lead electrocardiogram.
Publication TypeJournal Article
Year of Publication2007
AuthorsRautaharju PM, Prineas RJ, Zhang Z-M
JournalJ Electrocardiol
Volume40
Issue3
Pagination300-4
Date Published2007 Jul
ISSN1532-8430
KeywordsAged, Algorithms, Body Surface Potential Mapping, Coronary Artery Disease, Databases, Factual, Diagnosis, Computer-Assisted, Female, Humans, Information Storage and Retrieval, Male, Middle Aged, Quality Assurance, Health Care, Reproducibility of Results, Sensitivity and Specificity
Abstract

The spatial QRS/T angle has been identified as a strong predictor of adverse cardiac events. Mean QRS and T amplitudes from X, Y, and Z leads generated by a matrix transformation method are often used to calculate the QRS/T angle (QRS/T(matrix)). Many investigators find this procedure cumbersome. We used electrocardiographic data files of 14881 men and women aged 45 to 65 years from the Atherosclerosis in Communities study to derive a simple formula for estimated spatial QRS/T angle (QRS/T(simple)). QRS/T(simple) is calculated as the inverse cosine between the mean QRS and T vectors, which are approximated by 3 QRS(net) and T(net) amplitudes for each vector. QRS/T(simple) explained 79% of the variance of QRS/T(matrix) (r = 0.89). Using sex-specific thresholds, QRS/T(simple) detected abnormally wide QRS/T(matrix) values with a sensitivity of 91% and specificity of 88%. It is concluded that this simple method may provide a satisfactory substitute for QRS/T from the matrix transformation method.

DOI10.1016/j.jelectrocard.2006.11.003
Alternate JournalJ Electrocardiol
PubMed ID17292386
Grant ListN01-HC-55015 / HC / NHLBI NIH HHS / United States
N01-HC-55016 / HC / NHLBI NIH HHS / United States
N01-HC-55018 / HC / NHLBI NIH HHS / United States
N01-HC-55019 / HC / NHLBI NIH HHS / United States
N01-HC-55020 / HC / NHLBI NIH HHS / United States
N01-HC-55021 / HC / NHLBI NIH HHS / United States
N01-HC-55022 / HC / NHLBI NIH HHS / United States