Document Detail

Electrocardiogram signal variance analysis in the diagnosis of coronary artery disease--a comparison with exercise stress test in an angiographically documented high prevalence population.
MedLine Citation:
PMID:  8242912     Owner:  NLM     Status:  MEDLINE    
Variance electrocardiography (variance ECG) is a new resting procedure for detection of coronary artery disease (CAD). The method measures variability in the electrical expression of the depolarization phase induced by this disease. The time-domain analysis is performed on 220 cardiac cycles using high-fidelity ECG signals from 24 leads, and the phase-locked temporal electrical heterogeneity is expressed as a nondimensional CAD index (CAD-I) with the values of 0-150. This study compares the diagnostic efficiency of variance ECG and exercise stress test in a high prevalence population. A total of 199 symptomatic patients evaluated with coronary angiography was subjected to variance ECG and exercise test on a bicycle ergometer as a continuous ramp. The discriminant accuracy of the two methods was assessed employing the receiver operating characteristic curves constructed by successive consideration of several CAD-I cutpoint values and various threshold criteria based on ST-segment depression exclusively or in combination with exertional chest pain. Of these patients, 175 with CAD (> or = 50% luminal stenosis in 1 + major epicardial arteries) presented a mean CAD-I of 88 +/- 22, compared with 70 +/- 21 in 24 nonaffected patients (p < 0.01). Variance ECG provided a stochastically significant discrimination (p < 0.01) which was matched by exercise test only when chest pain variable was added to ST-segment depression as a discriminating criterion. Even then, the exercise test diagnosed single-vessel disease with a significantly lower sensitivity. At a cutpoint of CAD-I > or = 70, compared with ST-segment depression > or = 1 mm combined with exertional chest pain, the overall sensitivity of variance ECG was significantly higher (p < 0.01) than that of exercise test (79 vs. 48%). When combined, the two methods identified 93% of coronary angiography positive cases. Variance ECG is an efficient diagnostic method which compares favorably with exercise test for detection of CAD in high prevalence population.
J Nowak; I Hagerman; M Ylén; O Nyquist; C Sylvén
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical cardiology     Volume:  16     ISSN:  0160-9289     ISO Abbreviation:  Clin Cardiol     Publication Date:  1993 Sep 
Date Detail:
Created Date:  1994-01-03     Completed Date:  1994-01-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7903272     Medline TA:  Clin Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  671-82     Citation Subset:  IM    
Karolinska Institute, Department of Clinical Physiology, Huddinge, Sweden.
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MeSH Terms
Aged, 80 and over
Coronary Angiography*
Coronary Disease / diagnosis*,  epidemiology
Electrocardiography / methods*
Exercise Test*
Middle Aged

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