Document Detail

Variability of indexes for myocardial ischemia: a comparison of exercise treadmill test, ambulatory electrocardiographic monitoring and symptoms of myocardial ischemia.
MedLine Citation:
PMID:  2493043     Owner:  NLM     Status:  MEDLINE    
Fifty-four patients with chronic stable angina were studied to determine and compare weekly variability of indexes for the detection of myocardial ischemia. All patients underwent three single-blind placebo periods, each lasting 1 week. An exercise treadmill test, 24 h ambulatory electrocardiographic (Holter) monitoring (analyzed blindly) and an accurate diary of anginal attacks and nitroglycerin use were obtained at the end of each placebo period. An unbalanced, completely random component of variance analysis was used to calculate a component for within subject variability and a component for among subject variability. The coefficient of variation and percent variation (within subjects) of onset of chest pain during exercise were 19% and 30%, respectively; the corresponding values were 28% and 33% for onset of 1 mm ST depression, 15% and 15% for exercise duration, 44% and 27% for number of ischemic episodes/24 h, 56% and 43% for anginal frequency and 55% and 27% for nitroglycerin consumption, respectively. With use of this statistical method and variation within subjects, the change in the value of each variable necessary to exceed those attributable to spontaneous variation was determined. The trade-off between repeated measurements and number of subjects, the sample size estimated for planning studies and the minimal sample size for using various designs were also determined. Although the data indicate that all indexes for myocardial ischemia, both during exercise and during daily activity, vary considerably, but the exercise variables have less variability and are more reproducible.(ABSTRACT TRUNCATED AT 250 WORDS)
K Nademanee; P D Christenson; V Intarachot; H A Robertson; F V Mody
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of the American College of Cardiology     Volume:  13     ISSN:  0735-1097     ISO Abbreviation:  J. Am. Coll. Cardiol.     Publication Date:  1989 Mar 
Date Detail:
Created Date:  1989-04-05     Completed Date:  1989-04-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8301365     Medline TA:  J Am Coll Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  574-9     Citation Subset:  AIM; IM    
Department of Cardiology, Wadsworth Veterans Administration Medical Center, Los Angeles, California 90073.
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MeSH Terms
Ambulatory Care
Angina Pectoris / epidemiology,  physiopathology
Coronary Disease / drug therapy,  physiopathology*
Electrocardiography / methods*
Exercise Test*
Middle Aged
Monitoring, Physiologic / methods*
Nitroglycerin / therapeutic use
Research Design
Grant Support
R01 DA/HL-05485-01/DA/NIDA NIH HHS
Reg. No./Substance:

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

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