| Attenuation of increased regional myocardial oxygen consumption during exercise as a major cause of warm-up phenomenon. | |
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MedLine Citation:
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PMID: 8496525 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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OBJECTIVES: The aim of this study was to test the hypothesis that the warm-up phenomenon is attributable to a reduction of increased myocardial oxygen consumption rather than to increased coronary blood flow during exercise. BACKGROUND: The underlying mechanism of the warm-up phenomenon is not elucidated. METHODS: Thirteen patients with effort angina were subjected to two consecutive supine ergometer exercise tests performed 15 min apart. All patients had severe proximal stenosis (> 90%) in the left anterior descending coronary artery. Great cardiac vein flow was measured before and during exercise. Both regional myocardial oxygen consumption and adenosine release were determined. RESULTS: Exercise was continued for significantly longer before angina onset in the second than in the first exercise test (507 +/- 44 vs. 410 +/- 42 s, p < 0.01). The extent of ST segment depression in lead V5 of the electrocardiogram (ECG) was larger at the time of angina onset in the first (1.7 +/- 0.2 mm) than in the second (1.1 +/- 0.2 mm, p < 0.01) exercise test. Neither systemic hemodynamic variables nor great cardiac vein flow differed between the first and second exercise tests. In contrast, regional myocardial oxygen consumption assessed at 3 min of exercise was significantly (p < 0.01) less in the second than in the first test (8.0 +/- 0.8 vs. 8.7 +/- 0.9 ml/min). Adenosine release during the second test was higher (p < 0.05) than in the first test (2.5 +/- 0.5 vs. 3.9 +/- 0.5 nmol/min at 3 min of the first and second tests, p < 0.01). CONCLUSIONS: These results indicate that the warm-up phenomenon is not attributable to increased coronary flow but to attenuation of increased regional myocardial oxygen consumption, which may be mediated by adenosine A1 receptor activation. |
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Authors:
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Y Okazaki; K Kodama; H Sato; M Kitakaze; A Hirayama; M Mishima; M Hori; M Inoue |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Journal of the American College of Cardiology Volume: 21 ISSN: 0735-1097 ISO Abbreviation: J. Am. Coll. Cardiol. Publication Date: 1993 Jun |
Date Detail:
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Created Date: 1993-06-22 Completed Date: 1993-06-22 Revised Date: 2010-03-24 |
Medline Journal Info:
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Nlm Unique ID: 8301365 Medline TA: J Am Coll Cardiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 1597-604 Citation Subset: AIM; IM; S |
Affiliation:
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Osaka University School of Medicine, Japan. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological Adenosine / blood Adult Angina Pectoris / blood, metabolism*, physiopathology* Coronary Circulation* Female Hemodynamics Humans Male Middle Aged Myocardium / metabolism* Norepinephrine / blood Oxygen Consumption* Physical Exertion* |
| Chemical | |
Reg. No./Substance:
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51-41-2/Norepinephrine; 58-61-7/Adenosine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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