| Effects of spontaneous respiration on canine left ventricular function. | |
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MedLine Citation:
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PMID: 498435 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The purpose of this study was to determine the mechanism of the decrease in left ventricular stroke volume during spontaneous inspiration. We determined the transmural pressures of the left heart by measuring left atrial and diastolic left ventricular pressures relative to esophageal pressure. We estimated the directional changes in end-systolic and end-diastolic volumes of the left ventricle by determining the transit time of sound transmission between two ultrasonic crystals facing each other across the minor axis of the left ventricle. Left ventricular stroke volume decreased with spontaneous inspiratory effort as pleural pressure fell, regardless of whether lung volume increased or remained constant. The stroke volume was decreased during the fall in pleural pressure because of an increase in end-systolic volume with an essentially unchanged diastolic volume. Thus, the decrease in stroke volume was due to a decrease in ejection, rather than a decrease in filling of the left ventricle. We believe that left ventricular ejection was impeded by the fall in pressure around the heart relative to the pressure in the aorta. In spite of the essentially constant diastolic volume, diastolic left ventricular transmural pressure rose, suggesting that spontaneous inspiration decreases the diastolic compliance of the left ventricle. The change in diastolic compliance contributed to the decrease in stroke volume but was not the primary cause. |
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Authors:
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W R Summer; S Permutt; K Sagawa; A A Shoukas; B Bromberger-Barnea |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Circulation research Volume: 45 ISSN: 0009-7330 ISO Abbreviation: Circ. Res. Publication Date: 1979 Dec |
Date Detail:
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Created Date: 1980-01-19 Completed Date: 1980-01-19 Revised Date: 2008-11-21 |
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: 719-28 Citation Subset: IM; S |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Blood Pressure Cardiac Output* Diastole Dogs Esophagus / physiology Pleura / physiology Propranolol / administration & dosage Respiration* Stroke Volume* Systole Time Factors Ventricular Function |
| Chemical | |
Reg. No./Substance:
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525-66-6/Propranolol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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