Myocardial Oxygen Consumption During Exercise in Fasting and Lipemic Subjects*

Regan, Timothy J.; Timmis, Gerald C.; Gray, Murray R.; Binak, K; Hellems, Harper K.

doi:10.1172/jci104293

Cited by 47 publications

(23 citation statements)

References 18 publications

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“…The average mean LV myocardial blood flow rate of 61 ml/100 g-min in this group is similar to the value of 64 ml/100 gmin obtained previously in a series of patients with heart disease and normal coronary arteriograms who were studied at Roosevelt Hospital (6). It is similar also to control values obtained by others who measured single myocardial washout curves of '"Xe or He (2, 7), but is lower than those obtained by groups using the nitrous oxide technique (1,15,16), which has yielded a wide range of values in normal subjects (17). In the control subjects, the regional myocardial blood flow rates in the areas of LV supplied by the LAD and Circ.…”

Section: Regional Myocardial Perfusion and Coronary Arteriographic Lesupporting

confidence: 89%

The relationship between regional myocardial perfusion at rest and arteriographic lesions in patients with coronary atherosclerosis.

Cannon¹,

Schmidt²,

Weiss³

et al. 1975

J. Clin. Invest.

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AB STRA CT Measurements of mean left ventricular (LV) and regional myocardial blood flow rates were made at rest in 161 patients with '=Xe and a multiplecrystal scintillation camera. Myocardial perfusion rates were correlated with assessments of the degree of coronary artery disease made from the arteriograms obtained during the same studies. In patients with normal coronary arteries without heart failure, the presence of hypertension, aortic stenosis, or aortic insufficiency was not associated with changes in mean LV perfusion from the control value of 61±7 ml/100 g min. However, mean LV perfusion was significantly reduced in patients with normal coronary arteries who had cardiomyopathy and impaired ventricular performance. Mean LV perfusion was not significantly different from control valtues in patients with "mild" coronary artery disease (< 50% obstruction) or in patients with significant isolated disease (> 50% obstruction) of the left anterior descending (LAD) artery. Significant reductions in mean LV perfusion were found in patients with > 50% obstruction of two coronary arteries (LAD + right or LAD + circumflex) and in patients with triple-vessel disease.The average perfusion rate for regions distal to LAD obstructions in patients with isolated LAD disease was not lower than the LAD perfusion in control patients, but was significantly reduced in patients with LAD + right coronary artery disease (43±14 ml/100 g.min).In the latter group average perfusion distal to the LAD lesion was significantly lower than the average regional perfusion rate for the remainder of the LV. However, The data demonstrate that the presence of radiograplhically "mild" or significant isolated LAD coronary disease is not associated with reductions in mean LV perfusion at rest, but that mean LV perfusion is reduced in the presence of significant disease of two or three coronary arteries. None of the patients experienced angina dturing the resting studies and most had clinical evidence of ventricular failure. The observation of depressed LV perfusion in this group, as in the patients with cardiomvopathy, raises the possibility that a lowered resting blood supply may be adequate for a reduced level of per-formance of a diseased ventricle. The lack of selective reductions of regional perfusion at rest in the majority of the patients with LAD lesions suggests that regional myocardial blood flow must be measured during an intervention which increases myocardial oxygen consumption in order to assess the physiological significance of lesions which are observed at coronary arteriography.

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Section: Regional Myocardial Perfusion and Coronary Arteriographic Lesupporting

confidence: 89%

The relationship between regional myocardial perfusion at rest and arteriographic lesions in patients with coronary atherosclerosis.

Cannon¹,

Schmidt²,

Weiss³

et al. 1975

J. Clin. Invest.

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“…scatter of values than that described herein has been reported in the 12 patients with various cardiac disorders of Lombardo and associates (5) and in the 9 control subjects of Regan and colleagues (6). Their average rest-exercise myocardial oxygen extraction changes were + 3 and + 2 per cent, respectively.…”

Section: Clinical-physiological Correlationssupporting

confidence: 49%

“…For subjects in whom data were obtained, no significant difference was observed in pre-and postexercise resting values (0.2 < p < 0.4). 6 The degree of change during exercise was unrelated to absolute resting values of myocardial oxygen extraction or coronary venous oxygen saturation. Five subjects, two of whom had ischemic electrocardiographic changes, developed angina pectoris during the study.…”

Section: Homogeneity Of Coronary Venous Drainagementioning

confidence: 94%

Patterns of Human Myocardial Oxygen Extraction During Rest and Exercise*

Messer¹,

Wagman²,

Levine³

et al. 1962

J. Clin. Invest.

123

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Myocardial oxygen requirements are met by coronary blood flow and oxygen extraction from the arterial blood. The myocardial oxygen extraction coefficient (1) expresses the fraction of available oxygen in arterial blood removed by the myocardium: coronary A-Vo2/Ao2 X 100 = myocardial extraction percentage. Myocardial oxygen extraction during rest is approximately 70 to 75 per cent, exceeding that of all other organs (1, 2). This degree of extraction is equalled only by exercising skeletal muscle, in which increased oxygen requirements are met both by additional blood flow and by increased oxygen extraction. Earlier workers have noted a relative constancy of myocardial oxygen extraction under the widely varying conditions of rest, anemia, hypoxia, and increased left ventricular work, suggesting that coronary blood flow is altered commensurate with myocardial oxygen requirements (1, 3, 4). Case, Berglund and Sarnoff demonstrated that when coronary blood flow reserve was limited by experimental coronary constriction, myocardial extraction increased due to the combined stress of anemia and increased left ventricular work (3).The effect of exercise on coronary hemodynamics has received little attention. Lombardo and co-workers reported observations in 13 human subjects with various forms of heart disease (5). As part of another study, Regan and associates reported on the effects of exercise on the coronary circulation in nine normal subjects (6). This report will present myocardial oxygen extraction data from 108 patients at rest, and from 79 subjects during mild exercise. The physiological significance of myocardial oxygen extrac-* This work was supported by grants from the U. S. (7), and routine cardiac catheterization findings. The exercise electrocardiograms were interpreted according to the criteria of Mattingly, Fancher, Bauer and Robb (8).Four clinical states were selected for correlation with myocardial oxygen extraction patterns. The patients were grouped clinically according to the following criteria.Control. Patients having no symptoms or electrocardiographic, radiologic or physical findings suggesting coronary artery disease or congestive heart failure served as controls. Pulmonary capillary pressures were normal in all subjects except those with mild mitral stenosis. The range of diagnoses included functional systolic murmurs, patent ductus arteriosus, ventricular and atrial septal defects, mild aortic insufficiency, noncritical mitral stenosis (valve area greater than 1.5 cm'), tetralogy of Fallot, and mild coarctation of the aorta. Two had atypical chest pain without evidence to suggest coronary insufficiency.Coronary insufficiency. Patients judged to have coronary insufficiency on the basis of classical angina pectoris, documented myocardial infarction, and positive Master's test were placed in this group. In several cases the coronary vessels were assessed at operation, by coronary arteriography (9), or at necropsy. Several patients had coexisting congestive heart failure.Congestive heart failure. Th...

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“…In contrast to the elevated oxygen usage per 100 g of left ventricle per minute, in another high output state, 11 this parameter at 7.3 ml was below the normal value in the presence of a high cardiac output and left ventricular work. When compared with values from 16 resting normal subjects having a mean of 8.8 ml, 12 ' 13 myocardial oxygen usage was significantly reduced (P < 0.001). The lowest and highest hematocrits were associated respectively, with the largest and least deviation of oxygen usage from normal.…”

Section: Resultsmentioning

confidence: 79%

Myocardial Blood Flow and Oxygen Uptake During Acute Red Cell Volume Increments

Regan

Frank

Lehan

et al. 1963

Circulation Research

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The role of red cell mass in the regulation of coronary blood flow and myocardial oxygen consumption has been examined after acute transfusion of sedimented red cells. Patients with substantial blood-loss anemia had a lower than normal left ventricular oxygen uptake, despite a high myocardial blood flow at rest. A 50% rise of hematocrit reduced coronary flow markedly. Although systemic arterial pressure, cardiac output, and left heart work rose, myocardial oxygen consumption was unchanged. Red cell transfusion of normovolemic dogs resulted in a decrease of both myocardial flow and oxygen uptake associated with an elevation of time-tension index and left ventricular work, accelerated isometric contraction and prolonged systole. There was no evidence of ischemia or change of left ventricular hemodynamic parameters that would account for the reduced myocardial blood flow and oxygen uptake. These findings, in the presence of an increased oxygen carrying capacity and extraction, would appear to be related principally to enhanced blood viscosity.

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Myocardial Oxygen Consumption During Exercise in Fasting and Lipemic Subjects*

Cited by 47 publications

References 18 publications

The relationship between regional myocardial perfusion at rest and arteriographic lesions in patients with coronary atherosclerosis.

The relationship between regional myocardial perfusion at rest and arteriographic lesions in patients with coronary atherosclerosis.

Patterns of Human Myocardial Oxygen Extraction During Rest and Exercise*

Myocardial Blood Flow and Oxygen Uptake During Acute Red Cell Volume Increments

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