Myocardial oxygen consumption and mechanical efficiency of a perfused dogfish heart preparation

Davie P.S. and Franklin C.E. (1992) Myocardial oxygen consumption and mechanical efficiency of a perfused dogfish heart preparation. Journal of Comparative Physiology B, 162 3: 256-262. doi:10.1007/BF00357532


Author Davie P.S.
Franklin C.E.
Title Myocardial oxygen consumption and mechanical efficiency of a perfused dogfish heart preparation
Journal name Journal of Comparative Physiology B   Check publisher's open access policy
ISSN 0174-1578
Publication date 1992
Sub-type Article (original research)
DOI 10.1007/BF00357532
Volume 162
Issue 3
Start page 256
End page 262
Total pages 7
Publisher Springer-Verlag
Subject 2737 Physiology (medical)
2300 Environmental Science
1314 Physiology
1103 Clinical Sciences
Abstract Oxygen consumption of an in-pericardium heart preparation from the spiny dogfish (Squalus acanthias) was linearly related to cardiac power output. Basal oxygen consumption, predicted from the regression, was 0.127 μl · s-1 · g ventricle mass-1 and increased by 0.189 μl · s-1 · g ventricle mass-1 per milliwatt of power generated. From the relationship between cardiac power output and mechanical efficiency, mechanical efficiency was predicted to increase with cardiac power output to a maximum of 21 %. Mechanical efficiency was measured during volume loading and pressure loading at two power outputs (50% and 72% of maximum power output). At 50% of maximum power output, mechanical efficiency increased significantly by 2.87%, from 11.9±0.3% to 14.8±0.5% (n=7), when flow was halved and output pressure doubled to achieve the same power output. Similarly, at 72% of maximum power output, mechanical efficiency increased from 14.74±0.92% to 17.61±0.84% (n=6) when flow was halved and output pressure doubled to generate the same higher level of power output. The increased mechanical efficiency at higher output pressures is believed to result from cardiac myocytes working within a length range where they are able to generate the most tension during contraction and are most efficient. We speculate that the loss of mechanical efficiency associated with large changes in sarcomere length, when stroke volume is large, is a driving force behind the use of frequency as the principal means of increasing cardiac output as observed in more active fishes, birds and mammals.
Keyword Dogfish, Squalus acanthias
Heart
Mechanical efficiency
Oxygen consumption
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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Citation counts: TR Web of Science Citation Count  Cited 17 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 29 Mar 2016, 17:31:59 EST by Gail Walter