Effect of changes in blood CO2 level on coronary flow and myocardial O2 consumption

1960 ◽  
Vol 199 (2) ◽  
pp. 349-354 ◽  
Author(s):  
H. Feinberg ◽  
A. Gerola ◽  
L. N. Katz
Keyword(s):  
Oxygen Consumption ◽  
Coronary Flow ◽  
Myocardial Oxygen Consumption ◽  
Gas Mixture ◽  
Aortic Blood ◽  
Anesthetized Dogs ◽  
Myocardial O2 Consumption ◽  
Aortic Blood Pressure ◽  
Co2 Level ◽  
Oxygen Difference

The effect of hypo- and hypercapnia—induced by changing the respiratory gas mixture—on coronary flow and myocardial oxygen consumption was observed at constant cardiac output and over a broad range of pressure-loads in open-chested, anesthetized dogs. The correlation of cardiac effort (as indexed by the product of heart rate and mean aortic blood pressure) with myocardial oxygen consumption was not altered by increasing or decreasing the arterial CO2 content. Coronary blood flow was observed to be increased relative to the cardiac effort during hypercapnia but not during hypocapnia. The coronary arteriovenous oxygen difference and the percentage of oxygen extracted decreased during hypercapnia pari passu with the increase in venous oxygen content.

Myocardial oxygen consumption: the role of wall force and shortening

1977 ◽  
Vol 233 (4) ◽  
pp. H421-H430 ◽  
Author(s):  
K. T. Weber ◽  
J. S. Janicki
Keyword(s):  
Coronary Flow ◽  
Myocardial Oxygen Consumption ◽  
Left Ventricular ◽  
Steady State Response ◽  
State Response ◽  
Predominant Factor ◽  
Myocardial O2 Consumption ◽  
The Relationship ◽  
Oxygen Difference

The relationship between the force in the left ventricular wall during systole and myocardial O2 consumption (MVO2) was determined. In addition, the relative influence of the load imposed during shortening and fiber shortening on MVO2 was assessed. For this purpose, 14 servo-regulated, paced, isolated canine hearts were used and the steady-state response in total coronary flow and arteriovenous oxygen difference was measured. For both the isovolumetrically beating and the ejecting ventricle, statistically significant linear relations were observed between MVO2 and the integral of systolic force. These relations were not significantly different from one another, indicating that shortening was not a determinant of MVO2. Moreover, when ejecting an isolumetric beats of equivalent developed force were compared, a difference in MVO2 (deltaMVO2) was found. deltaMVO2 was a function of the force integral difference between these contractions and not fiber shortening. Thus, under the conditions of this experiment, the integral of systolic force that includes developed force and shortening load is the predominant factor regulating MVO2 for any given contractile state, whereas the influence of fiber shortening is negligible.

Effect of Catecholamines, l-Epinephrine and l-Norepinephrine on Coronary Flow and Oxygen Metabolism of the Myocardium

1958 ◽  
Vol 193 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Harold Feinberg ◽  
Louis N. Katz
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Coronary Flow ◽  
Myocardial Oxygen Consumption ◽  
Oxygen Metabolism ◽  
Aortic Pressure ◽  
Coronary Vasodilatation ◽  
Oxygen Difference ◽  
Mean Aortic Pressure

The effect of continuously infused intravenous l-epinephrine and l-norepinephrine (0.1–2.5 gamma/kg/min.) was determined in the open-chest, anesthetized dog prepared for measurement of total coronary flow. Coronary blood flow, myocardial oxygen availability and coronary venous oxygen content consistently increased after catecholamine administration despite wide fluctuations, above and below control values, in heart rate and mean aortic pressure at constant cardiac output. Thus, there was a significant decrease in the coronary arteriovenous oxygen difference after catecholamine administration. The increase in coronary flow and decrease in the coronary A-V oxygen difference were seen even when blood pressure and heart rate were lowered. It is concluded that the departure from the usual relationship between coronary flow and myocardial oxygen consumption is attributable to coronary vasodilatation. However, myocardial oxygen consumption is still the primary factor controlling coronary flow during catecholamine action.

Effects of flow, perfusion pressure, and oxygen consumption on cardiac capillary exchange

1995 ◽  
Vol 78 (4) ◽  
pp. 1350-1359 ◽  
Author(s):  
D. F. Cousineau ◽  
C. A. Goresky ◽  
C. P. Rose ◽  
A. Simard ◽  
A. J. Schwab
Keyword(s):  
Oxygen Consumption ◽  
Surface Area ◽  
Coronary Flow ◽  
Myocardial Oxygen Consumption ◽  
Perfusion Pressure ◽  
Multiple Indicator Dilution ◽  
Permeability Surface ◽  
Anesthetized Dogs ◽  
Capillary Exchange ◽  
Area Product

The roles of blood flow, local oxygen consumption, and perfusion pressure on cardiac transcapillary exchange were characterized in closed-chest anesthetized dogs by use of the multiple-indicator dilution technique. Occlusion of the carotid arteries or injection of dipyridamole increased coronary flow to significantly higher values compared with a group of animals in a basal state obtained in a previous study. Carotid occlusion resulted in a significant increase in perfusion pressure and myocardial oxygen consumption, whereas these two variables were significantly reduced after dipyridamole. For the whole group of animals, the capillary permeability-surface area product for sucrose increased with coronary flow, which appeared to be the important controller for this microcirculatory exchange parameter. Perfusion pressure and myocardial oxygen consumption also regulated permeability-surface area product values, although to a lesser extent than flow. The heterogeneity of transit times in the capillaries was reduced at high coronary flow values, despite large differences in the cardiac utilization of oxygen. The data suggest that cardiac capillary exchange responds mostly to hemodynamic changes originating at the precapillary level.

Effect of erythrocyte storage and oxyhemoglobin affinity changes on cardiac function

1985 ◽  
Vol 248 (4) ◽  
pp. H508-H515 ◽  
Author(s):  
C. S. Apstein ◽  
R. C. Dennis ◽  
L. Briggs ◽  
W. M. Vogel ◽  
J. Frazer ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Coronary Flow ◽  
Myocardial Oxygen Consumption ◽  
Myocardial Function ◽  
Contractile Function ◽  
Storage Conditions ◽  
Tissue Oxygen ◽  
Biochemical Treatment ◽  
Stress States ◽  
Stored Blood

Storage of blood can depress erythrocyte 2,3-diphosphoglycerate (DPG) levels and thereby increase oxyhemoglobin affinity and potentially decrease capillary-to-tissue oxygen transport. We measured myocardial function and metabolism in isolated rabbit hearts with fixed coronary flow under basal conditions and during isoproterenol stress at 37 and 30 degrees C, comparing high and low oxyhemoglobin affinity (OHA) erythrocytes. The high OHA state resulted from standard storage conditions, which caused depressed values of DPG and P50 (the oxygen tension at which hemoglobin is 50% saturated). The low OHA erythrocytes were initially stored and then underwent biochemical treatment to restore the DPG and P50 values to normal. The low OHA cells released more oxygen, and myocardial oxygen consumption and contractile function were increased relative to the high OHA cells during both the basal and stress states at both 37 and 30 degrees C. These observations may be relevant for patients with limited coronary flow when such patients receive large transfusions of stored blood.

Altered myocardial oxygen consumption after coronary occlusion in anesthetized dogs

1975 ◽  
Vol 89 (3) ◽  
pp. 333-337 ◽  
Author(s):  
Nallan C. Ramakrishna ◽  
Burton E. Sobel ◽  
William E. Shell ◽  
James W. Covell
Keyword(s):  
Oxygen Consumption ◽  
Myocardial Oxygen Consumption ◽  
Coronary Occlusion ◽  
Anesthetized Dogs
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