Document Detail

Increase in the resistance of stenotic coronary segment by intravenous infusion of isoproterenol.
MedLine Citation:
PMID:  6846053     Owner:  NLM     Status:  MEDLINE    
The effects of intravenous infusion of isoproterenol on stenosis resistance were studied in the anesthetized open-chest dog. The circumflex coronary artery (LCx) was isolated near its origin and an electromagnetic flow transducer was placed around the vessel for measuring coronary flow. A polyethylene catheter was inserted into the small branch of LCx for monitoring distal coronary pressure. LCx was constricted with a thick cotton string to a degree of obstruction that eliminated reactive hyperemia following a 20-second coronary occlusion. The coronary resistance across the stenotic segment (RL) was calculated as the pressure gradient across the stenosis divided by coronary flow. Isoproterenol was infused intravenously in a dose to keep the heart rate at a level 25-30% above the control with and without coronary constriction. For maintaining the ascending aortic pressure at the pre-isoproterenol level, the descending thoracic aorta was constricted with a tape. In the absence of coronary constriction, the vascular resistance of large coronary arteries was not affected by isoproterenol with a significant increase in coronary flow. In the presence of coronary stenosis, isoproterenol markedly increased RI regardless of additional aortic constriction. The magnitude of the increase in RL during aortic constriction varied directly with the percent increase in the pressure gradient across the coronary stenosis. Pacing-tachycardia essentially did not affect RL. These results suggest that isoproterenol increased the vascular resistance of the stenotic segment with fixed caliber.
D Saito; K Yasuhara; K Takeda; T Hyodo; A Fujii; T Uchida; Y Abe; S Haraoka; H Nagashima
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Acta medica Okayama     Volume:  37     ISSN:  0386-300X     ISO Abbreviation:  Acta Med. Okayama     Publication Date:  1983 Feb 
Date Detail:
Created Date:  1983-06-23     Completed Date:  1983-06-23     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0417611     Medline TA:  Acta Med Okayama     Country:  JAPAN    
Other Details:
Languages:  eng     Pagination:  59-66     Citation Subset:  IM    
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MeSH Terms
Blood Pressure / drug effects
Coronary Disease / physiopathology*
Coronary Vessels / drug effects*,  physiopathology
Heart Rate / drug effects
Isoproterenol / pharmacology*
Vascular Resistance / drug effects*
Reg. No./Substance:

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

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