| Regulation of myocardial blood flow by oxygen consumption is maintained in the failing heart during exercise. | |
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MedLine Citation:
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PMID: 10066674 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The hemodynamic abnormalities and neurohumoral activation that accompany congestive heart failure (CHF) might be expected to impair the increase in coronary blood flow that occurs during exercise. This study was performed to determine the effects of CHF on myocardial oxygen consumption and coronary blood flow during exercise. Coronary blood flow was measured in chronically instrumented dogs at rest, during 2 stages of graded treadmill exercise under control conditions (n=10), and after the development of CHF produced by 3 weeks of rapid ventricular pacing (n=9). In the normal dogs, coronary blood flow increased during exercise in proportion to the increase in the heart rate x the left ventricular systolic blood pressure product (RPP). After the development of CHF, resting myocardial blood flow was 25% lower than normal (P<0.05). Myocardial blood flow increased during the first stage of exercise, but then failed to increase further during the second stage of exercise despite an additional increase in the RPP. Myocardial oxygen consumption during exercise was significantly lower in animals with CHF and paralleled coronary flow. Despite the lower values for coronary blood flow in animals with CHF, there was no evidence for myocardial ischemia. Thus, even during the second level of exercise when coronary flow failed to increase, myocardial lactate consumption continued and coronary venous pH did not fall. In addition, the failure of coronary flow to increase as the exercise level was increased from stage 1 to stage 2 was not associated with a further increase in myocardial oxygen extraction. Thus, cardiac failure was associated with decreased myocardial oxygen consumption and failure of oxygen consumption to increase with an increase in the level of exercise. This abnormality did not appear to result from inadequate oxygen availability, but more likely represented a reduction of myocardial oxygen usage with a secondary decrease in metabolic coronary vasodilation. |
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Authors:
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J H Traverse; P Melchert; G L Pierpont; B Jones; M Crampton; R J Bache |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Circulation research Volume: 84 ISSN: 0009-7330 ISO Abbreviation: Circ. Res. Publication Date: 1999 Mar |
Date Detail:
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Created Date: 1999-04-13 Completed Date: 1999-04-13 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0047103 Medline TA: Circ Res Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 401-8 Citation Subset: IM |
Affiliation:
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Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Coronary Circulation / physiology* Coronary Vessels / metabolism Dogs Echocardiography Heart / physiopathology* Heart Failure / pathology, physiopathology*, ultrasonography Heart Ventricles Hemodynamics / physiology Hydrogen-Ion Concentration Lactic Acid / metabolism Motor Activity / physiology* Myocardium / metabolism, pathology Organ Size Oxygen Consumption / physiology* Vascular Resistance / physiology Veins / metabolism |
| Grant Support | |
ID/Acronym/Agency:
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HL-20598/HL/NHLBI NIH HHS; HL-21872/HL/NHLBI NIH HHS; HL-32427/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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50-21-5/Lactic Acid |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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