Document Detail

Computer quantitation of Q-T and terminal T wave (aT-eT) intervals during exercise: methodology and results in normal men.
MedLine Citation:
PMID:  7223664     Owner:  NLM     Status:  MEDLINE    
Computer-quantitated measurements of the Q-T intervals, the Q-T/Q-Tc ratio (Q-T/corrected Q-T) and the terminal T wave (apex to end of T [aT-eT] interval) were evaluated in resting and exercise electrocardiograms of 130 normal men with a mean age of 40 years. Pseudo-orthogonal, bipolar X, Y and Z axis leads were recorded during treadmill exercise testing, and 25 consecutive QRS-T complexes from standing rest and three exercise stages were computer-averaged. The Q-T intervals, Q-T/Q-Tc ratio and aT-eT interval measurements were then computed in the X and Z axis leads only, because the Y lead proved to be too noisy for accurate interpretation. A correlation coefficient of 0.9830 resulted between measurements made manually from the plotted, composite QRS-T complexes and those made by computer. No significant differences , in the paired sense, were found between any of the measurements. Measurements made on the Z axis lead; however, the differences in the measurements remained constant across all stages of exercise. A Q-T/Q-Tc ratio of greater than 1.08, previously reported to be a reliable indicator of coronary disease, was observed in the majority of our normal subjects during exercise. Although the Q-T interval is substantially influenced by many factors, the aT-eT interval proved not to be age- or heart rate-dependent. It appears that the aT-eT interval can be measured with a high degree of reliability during exercise and it may prove to be a relatively specific indicator of repolarization alterations that occur with myocardial ischemia.
J O'Donnell; S B Knoebel; D E Lovelace; P L McHenry
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of cardiology     Volume:  47     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  1981 May 
Date Detail:
Created Date:  1981-06-23     Completed Date:  1981-06-23     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1168-72     Citation Subset:  AIM; IM    
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MeSH Terms
Age Factors
Coronary Disease / diagnosis*
Exercise Test / methods*
Heart Rate
Middle Aged
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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