Document Detail

Nonischemic end-systolic performance. Effect of alterations in regional and global left ventricular contractility.
MedLine Citation:
PMID:  10393394     Owner:  NLM     Status:  MEDLINE    
Nonischemic end-systolic performance decreases during ischemia. These changes in performance are likely to be dependent on the size and site of the ischemic zone, as well as the prevailing loading conditions. This study was designed to examine the effect of regional and generalized changes in inotropy on nonischemic end-systolic performance, independent of the ischemic zone size. Twenty dogs were instrumented with sonomicrometers and micromanometer pressure gauges. End-systolic pressure-thickness relationship data were obained during vena-caval balloon inflation. Measurements were obtained before and 90 s after left circumflex (LC) artery occlusion. Then, simultaneous with the occlusion of the LC artery, isoproterenol (0.04 microg/ml) was infused into the left anterior descending artery. After recovery, the same protocol was repeated before and after propranolol (0.5 mg/kg). In a separate set of animals, the same measurements were made following 2.5 and 5 microg/kg/min dobutamine. The effect of ischemia on the nonischemic end-systolic pressure-thickness relationship was expressed as the extent to which the relationship is shifted to the left. Infusion of intracoronary isoproterenol into the perfusion bed of the nonischemic zone produced a significant increase in the slope of the end-systolic pressure-thickness relationship. During ischemia, however, the extent of leftward shift of this relationship was less than that following beta-blockade. Intravenous dobutamine resulted in a dose-dependent increase in the slope of the nonischemic end-systolic pressure thickness relationship, but the extent of leftward displacement of the relationship in response to regional ischemia was less than that following the control occlusion. The nonischemic segment is coupled with the nonfunctioning ischemic zone in such a way that it is required of the nonischemic segment to operate at decreased end-systolic thickness for any end-systolic pressure, the extent of which is to be determined, in part, by the size of the ischemic zone and the contractile state of the nonischemic myocardium. The lower the contractile state prior to coronary occlusion the greater extent of leftward shift of the pressure-thickness relationship.
T E Meyer; S Perlini; P Foëx
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Cardiology     Volume:  91     ISSN:  0008-6312     ISO Abbreviation:  Cardiology     Publication Date:  1999  
Date Detail:
Created Date:  2000-01-04     Completed Date:  2000-01-04     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  1266406     Medline TA:  Cardiology     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  14-24     Citation Subset:  IM    
Department of Cardiovascular Medicine, Radcliffe Infirmary and University of Oxford, UK.
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MeSH Terms
Dobutamine / pharmacology
Dose-Response Relationship, Drug
Hemodynamics / drug effects,  physiology
Infusions, Intra-Arterial
Infusions, Intravenous
Isoproterenol / pharmacology
Myocardial Contraction / drug effects,  physiology*
Myocardial Ischemia / diagnosis,  physiopathology*
Propranolol / pharmacology
Systole / drug effects,  physiology*
Ventricular Function, Left / drug effects,  physiology*
Reg. No./Substance:
34368-04-2/Dobutamine; 525-66-6/Propranolol; 7683-59-2/Isoproterenol

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

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