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Control of the Heterogeneity of O2 Saturation in Small Myocardial Veins

  • Harvey R. Weiss
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 200)

Summary

There is a wide variability in the measured O2 saturations (SvO2) of small myocardial veins (20–100 µm). The purpose of the present study was to examine several factors that contributed to this variablity. Studies were conducted on anesthetized open-chest dogs. The role of β-adrenoceptors and flow in the control of the heterogeneity of SvO2 was assessed. The hearts were quick-frozen in liquid N and the SvO2 in the subepicardial and subendocardial (ENDO) regions of the left ventricule was determined by microspectrophotometry. Under control conditions, ENDO SvO2 averaged 35% with a variance of 337. The control variance was much moe than that of the methodological errors. With propranol or practolol, variance was reduced by about half, e.g. ENDO SvO2 variance was 145 with propranolol. This reduction in SvO2 variance could be prevented by isoproterenol. When flow is reduced by partial occlusion the SvO2 values were skewed toward lower saturations. When nitroglycerin is admnistered during this partial occlusion, the SvO2 distribution is restored toward normal. It can be concluded that some of the variability of SvO2 in the heart is control by β1-adrenoceptors. There also appears to be an inverse relationship between coronary blood flow and SvO2 heterogeneity. Further work is necessary to determine what other fctors control the variability of SvO2.

Keywords

Myocardial Blood Flow Coronary Blood Flow Blood Flow Rate Partial Occlusion High Energy Phosphate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Press, New York 1986

Authors and Affiliations

  • Harvey R. Weiss
    • 1
  1. 1.Heart and Brain Circulation Laboratory Department of Physiology and BiophysicsUniversity of Medicine and Dentistry of New Jersey Rutgers Medical SchoolPiscatawayUSA

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