Document Detail

Cardiopulmonary exercise testing in syndrome X.
MedLine Citation:
PMID:  8438700     Owner:  NLM     Status:  MEDLINE    
Patients with syndrome X have been found to have an abnormal coronary blood flow reserve. The physical performance during exercise, however, has been incompletely investigated. Cardiopulmonary exercise testing (CPX) is a reliable noninvasive method to provide indexes of lung, heart, circulation, and muscle functions. In 15 patients (10 women) with syndrome X and in age and sex-matched normal individuals, CPX was performed twice a day (8 AM and 4 PM) on two separate occasions 2 months apart. Time and oxygen consumption at peak exercise, at ventilatory anaerobic and electrocardiographic thresholds, as well as norepinephrine plasma concentrations at each work load and at peak exercise in both tests were obtained. In syndrome X in both evaluations, the 4 PM performance was characterized by an earlier onset of both ventilatory anaerobic and electrocardiographic thresholds despite lower values of VO2 and double-product, and by a greater peak ST segment depression despite similar total exercise time, VO2, and double-product. No difference between tests was found in the norepinephrine response to exercise. Normal subjects showed reproducible CPX and hormonal responses in the two tests. Thus these data may suggest a circadian variation of coronary vascular response to exercise in patients with syndrome X, leading to a lower ischemic threshold early in the afternoon. The parallel earlier onset of the ventilatory anaerobic threshold may reflect a concomitant abnormal muscular blood flow response (that is, vasoconstriction of working muscle arteries), suggesting a link between coronary and peripheral circulations.
P Montorsi; P G Agostoni; L Annoni; P Vincenzi; M D Guazzi
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  American heart journal     Volume:  125     ISSN:  0002-8703     ISO Abbreviation:  Am. Heart J.     Publication Date:  1993 Mar 
Date Detail:
Created Date:  1993-03-25     Completed Date:  1993-03-25     Revised Date:  2006-02-27    
Medline Journal Info:
Nlm Unique ID:  0370465     Medline TA:  Am Heart J     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  711-7     Citation Subset:  AIM; IM    
Istituto di Cardiologia, University of Milan, Italy.
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MeSH Terms
Anaerobic Threshold / physiology
Angina Pectoris / diagnosis*,  physiopathology
Circadian Rhythm / physiology*
Coronary Angiography*
Coronary Circulation / physiology
Coronary Vessels / physiology*
Exercise Test*
Exercise Tolerance / physiology
Middle Aged
Norepinephrine / blood
Reg. No./Substance:

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