Document Detail

Myocardial ischaemia during tachycardia--not due to an increase in myocardial oxygen demand.
MedLine Citation:
PMID:  3920764     Owner:  NLM     Status:  MEDLINE    
It is generally believed that an increase in heart rate will be accompanied by an increase in myocardial oxygen demand (MVO2), but in a recent publication this concept has been challenged; we present data supporting the view that an increase in heart rate is not necessarily accompanied by an increase in MVO2. Our data are based on studies on dogs in five phases: (a) normal coronary arteries; (i) with normal heart rate; (ii) with tachycardia induced by a pacemaker; and (iii) with normal heart rate; and (b) with a constricted left anterior descending coronary artery: (i) with normal heart rate; and (ii) with induced tachycardia. MVO2 remained unchanged both per beat and per unit of time. Neither global nor regional myocardial function in the area supplied by the constricted artery changed during tachycardia. The reason for myocardial ischaemia should therefore not be attributed to an increase in MVO2 if the diameter of the heart is not increased, and attention should rather be focused on inadequate diastolic perfusion time and possible redistribution of blood from the potentially ischaemic zone.
A Coetzee; D Holland; P Foëx; A Ryder; L Jones
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde     Volume:  67     ISSN:  0256-9574     ISO Abbreviation:  S. Afr. Med. J.     Publication Date:  1985 Mar 
Date Detail:
Created Date:  1985-05-17     Completed Date:  1985-05-17     Revised Date:  2014-09-12    
Medline Journal Info:
Nlm Unique ID:  0404520     Medline TA:  S Afr Med J     Country:  SOUTH AFRICA    
Other Details:
Languages:  eng     Pagination:  496-9     Citation Subset:  IM    
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MeSH Terms
Carbon Dioxide / blood
Coronary Disease / etiology*
Heart / physiopathology
Heart Rate
Myocardium / metabolism*
Oxygen Consumption*
Tachycardia / complications*,  metabolism
Time Factors
Reg. No./Substance:
142M471B3J/Carbon Dioxide

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

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