Document Detail

The effects of increasing mean arterial pressure on left ventricular output in newborn lambs.
MedLine Citation:
PMID:  2364497     Owner:  NLM     Status:  MEDLINE    
We developed a preparation in which the mean arterial pressure of the newborn lamb is varied with little change in left ventricular preload. Seven lambs underwent balloon atrial septostomy and were instrumented with vascular catheters, an electromagnetic flow transducer on the aorta, and a balloon occluder on the aorta. Four different preload conditions were established by volume infusion or withdrawal. Aortic flow was measured continuously during gradual occlusion of the aorta. Curves relating mean left atrial pressure to stroke volume before balloon inflation showed a plateau, with little increase in stroke volume with increases in atrial pressure above 7 mm Hg. With balloon inflation, stroke volume decreased linearly with increases in mean arterial pressure. Curves relating left atrial pressure to stroke volume constructed at constant mean atrial pressure showed no plateau but showed continued increases in stroke volume as left atrial pressure was increased to 10 mmHg. When mean arterial pressure is constant, the Starling mechanism is operative in newborn left ventricles. The plateau in newborn lamb function curves is due to increases in mean arterial pressure that accompany volume infusion.
G F Van Hare; J A Hawkins; K G Schmidt; A M Rudolph
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation research     Volume:  67     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1990 Jul 
Date Detail:
Created Date:  1990-08-13     Completed Date:  1990-08-13     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  78-83     Citation Subset:  IM    
Cardiovascular Research Institute, University of California, San Francisco 94143.
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MeSH Terms
Animals, Newborn
Blood Pressure / physiology*
Fetal Heart / physiology
Fetus / physiology
Heart / physiology
Heart Ventricles
Stroke Volume*
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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