| Power-afterload relation in the failing human ventricle. | |
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MedLine Citation:
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PMID: 1537089 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Animal studies have shown that the power output of the left ventricle is related to afterload by a bell-shaped curve. Furthermore, the normal ventricle operates at the maximum power point, whereas the diseased ventricle operates off the maximum power point because of increased afterload. We studied this relation in eight patients with dilated cardiomyopathy. A high-fidelity catheter with micromanometer pressure and electromagnetic velocity transducers was used to measure blood pressure and flow velocity in the ascending aorta. The latter was converted into volumetric flow by calibrating with the simultaneously determined thermodilution cardiac output. Ventricular power was calculated by dividing the integral of the aortic blood pressure-flow product by the duration of the cardiac cycle. Intravenous nitroprusside was used to alter afterload and the power-afterload relation was obtained by plotting power against mean aortic blood pressure. In all patients, as blood pressure was lowered initially, the power output of the left ventricle increased. As the dose of nitroprusside was increased further, the total power either plateaued or actually decreased. The averaged power and the mean blood pressure at control were 1.00 +/- 0.62 W and 92 +/- 9.3 mm Hg, respectively. The averaged maximum increase in power with nitroprusside was 22%, to 1.22 +/- 0.73 W, and this occurred at a mean pressure of 80 +/- 8.8 mm Hg. This study showed that the power-afterload relation in the human ventricle has a maximum power point at some intermediate level of afterload, similar to that found in animal studies.(ABSTRACT TRUNCATED AT 250 WORDS) |
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Authors:
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Y C Chiu; P W Arand; J D Carroll |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Circulation research Volume: 70 ISSN: 0009-7330 ISO Abbreviation: Circ. Res. Publication Date: 1992 Mar |
Date Detail:
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Created Date: 1992-03-27 Completed Date: 1992-03-27 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: 530-5 Citation Subset: IM |
Affiliation:
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Department of Medicine, University of Chicago, Illinois. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Blood Flow Velocity Cardiomyopathy, Dilated / physiopathology* Dose-Response Relationship, Drug Female Heart Catheterization Heart Function Tests Hemodynamics / drug effects Humans Male Middle Aged Nitroprusside / administration & dosage Ventricular Function, Left / drug effects, physiology* |
| Chemical | |
Reg. No./Substance:
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15078-28-1/Nitroprusside |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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