Intracapillary hemoglobin oxygen saturation and oxygen consumption in different layers of the left ventricular myocardium

Holtz, J.; Grünewald, W.; Manz, R; Restorff, W. v.; Bassenge, E.

doi:10.1007/bf00585535

Cited by 51 publications

(21 citation statements)

References 31 publications

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“…Recent studies (Holtz et al, 1977;Weiss et al, 1978) have indicated that the rate of oxygen consumption is greater in the subendocardium than in the subepicardium, and we have demonstrated previously that the tissue lactate level rises faster in the subendocardium than in the subepicardium after complete stoppage of all coronary arterial inflow to the working left ventricle . These findings suggest that a metabolic stimulus for reactive hyperemia would be more pronounced and sustained longer in the subendocardium than in the subepicardium.…”

Section: Discussionsupporting

confidence: 48%

“…This dependence may be related to the production of a vasodilator metabolite in the myocardium. Recent studies indicate that for the left ventricle the level of metabolic activity is greater in the subendocardium than in the subepicardium (Holtz et al, 1977;Weiss et aL, 1978), and it has been noted in the totally ischemic left ventricle that the buildup of anaerobically produced lactate is more rapid in the subendocardium . These results suggest that metabolic conditions favoring reactive hyperemia may be more pronounced and sustained longer in the subendocardium.…”

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confidence: 99%

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High energy phosphate stores and lactate levels in different layers of the canine left ventricle during reactive hyperemia.

Dunn¹,

McDonough²,

Griggs³

1979

Circulation Research

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SUMMARY To study postischemic recovery of myocardial energy metabolism in relation to the reactive hyperemic response, the tissue levels of creatine phosphate (CP), adenosine triphosphate (ATP), and lactate were estimated in the outer, middle, and inner layers of the left ventricle before, during, and at several times after a 20-second bilateral coronary arterial occlusion in the open-chest dog. The reactive hyperemic response was characterized by monitoring blood flow in the cannulated coronary sinus in a separate group of dogs. Substantial changes in myocardial CP and lactate, but not ATP, were produced by the occlusion, and reciprocal transmural gradients in CP and lactate occurred such that CP was lowest and lactate was highest in the inner layer. Recovery of high energy phosphate stores (CP + ATP) occurred long before blood flow returned to the preocclusion level, this being achieved in two of the three layers after completion of only 29% of the reactive hyperemic response when the blood flow debt repayment was 151%. Lactate returned to control levels during the response, but recovery times in the different layers were delayed compared to those for the high energy phosphate stores. A transmural lactate gradient was maintained as the regional levels declined, and recovery times were different for each of the three layers, being longest in the inner layer. The results suggest that during the reactive hyperemic response (1) kinetlcally different processes are involved in the repletion of energy stores and the removal of anaerobically produced metabolites, and (2) metabolic vasodilation of coronary vessels probably is more pronounced and sustained longer in the inner than in the outer ventricular layer. Ore Ren 44: 788-795, 1979 ALTHOUGH considerable information is available regarding the nature of the reactive hyperemic response in the heart (Olsson, 1975), relatively little is known about the changes in myocardial energy metabolism which accompany this response. One characteristic of the reactive hyperemic response in the heart is overpayment of the blood flow debt incurred during the period of coronary arterial occlusion. Although previous studies (Bache et al., 1974; Eikens and Wilcken, 1974) have provided indirect evidence that the large volume of reactive hyperemic blood flow is in excess of that needed to reverse the changes in myocardial energy metabolism caused by the occlusion, the temporal relationships between reactive hyperemic blood flow and such metabolic events in the myocardium as replenishment of reduced high energy phosphate stores and removal of anaerobically produced lactate have not been established. One purpose of this study was to establish these relationships.Another characteristic of the reactive hyperemic response in the heart is dependence of its volume and duration on the level of metabolic activity in the myocardium during the occlusion period. This dependence may be related to the production of a vasodilator metabolite in the myocardium. Recent studies indicate that for the le...

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Section: Discussionsupporting

confidence: 48%

mentioning

confidence: 99%

High energy phosphate stores and lactate levels in different layers of the canine left ventricle during reactive hyperemia.

Dunn¹,

McDonough²,

Griggs³

1979

Circulation Research

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“…No differences were found between subepicardial and subendocardial O2 consumption after T 4 administration. As others have shown, under control conditions, subepicardial O2 consumption is lower than subendocardial (Holtz et al, 1977b;. In some types of stress, subendocardial O2 consumption does not increase to the same extent as does subepicardial (Vinten-Johansen and , whereas, in others, the increase is proportional (Weiss, 1979a).…”

Section: Hemodynamic and Bloodmentioning

confidence: 72%

Thyroxine-induced hypertrophy of the rabbit heart. Effect on regional oxygen extraction, flow, and oxygen consumption.

Talafih¹,

Briden²,

Weiss³

1983

Circulation Research

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SUMMARY. The effects of the administration of 0.5 or 1 mg/kg of 1-thyroxine for 3 or 16 days were studied in 55 New Zealand white rabbits. Heart size was 29% above control after 16 days of 1-thyroxine, despite lower body weights. In an anesthetized open-chest animal, regional microspectrophotometric observations of small arteries and veins to determine oxygen extraction were combined with regional blood flow measurements using radioactive microspheres to determine regional oxygen consumption by the Fick principle. Vascular flow reserves were studied through measurement of blood flow after the administration of chromonar HC1, 10 mg/kg. Myocardial oxygen consumption was, respectively, 2.4 and 3.8 times control after 3 and 16 days of 1-thyroxine. This was accompanied by significant increases in both coronary blood flow and oxygen extraction. In control, oxygen extraction and consumption were higher in the subendocardial region compared to the subepicardial area. No significant regional differences were found in flow, oxygen extraction, or consumption after 1-thyroxine administration. Chromonar increased coronary blood flow 2.8 times in the control animals, but did not significantly increase flow or decrease vascular resistance in the rabbits given 1-thyroxine. Adenosine increased coronary blood flow 3.5 times in the control animals but only 2.2 times in animals given 1-thyroxine for 3 days. Animals given 1-thyroxine had hypertrophied hearts with increased oxygen consumption, markedly increased flow, and increased oxygen extraction but without regional left ventricular differences. (Circ Res 52: 272-279, 19S3)

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“…Under basal conditions, endocardial blood flow is thought to be slightly higher than or equal to the epicardial blood flow (10,21). Owing to a variety of factors, including greater wall stresses and intramyocardial pressure (7,8), and enhanced endocardial metabolism (9,10,22,23), subendocardial oxygen consumption is -1.5-fold greater than subepicardial oxygen consumption under normal conditions (5,6,10). Since tissue pressure during systole is so much greater in the subendocardium than in the subepicardium, endocardial coronary flow is largely restricted to diastole (7,8).…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, these same indices only reflect global changes in adenosine levels and cannot detect regional differences in extracellular adenosine. The mammalian myocardium is a heterogeneous tissue and the subepicardial and subendocardial regions differ physically, metabolically, and functionally (5)(6)(7)(8)(9)(10). Little information is available regarding spatial heterogeneities in extracellular metabolite levels.…”

mentioning

confidence: 99%

Transmural distribution of extracellular purines in isolated guinea pig heart.

Zhu¹,

Headrick²,

Berne³

1991

Proc. Natl. Acad. Sci. U.S.A.

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The purine adenosine appears to be involved in regulation of coronary vascular tone. Little is known concerning the levels and distribution of adenosine and related purines in the extracellular fluid of the heart. We have measured epicardial and endocardial levels of adenosine, inosine, hypoxanthine, AMP, and IMP in isolated constant flow perfused guinea pig hearts by using a recently developed technique with porous nylon sampling discs. Venous effluent purine levels were also measured. Concentrations of all purines measured, excluding IMP, were significantly higher in endocardial fluid samples than in epicardial fluid samples (P < 0.05). Conversely, IMP levels were significantly lower in endocardial than in epicardial samples. The magnitude of the endocardial/epicardial ratios for adenosine, inosine, hypoxanthine, AMP, and IMP were '12:1, 4:1, 5:1, 4:1, and 1:2, respectively. To assess cellular damage, lactate dehydrogenase activity was measured in all fluid samples and was not significantly different in endocardial and epicardial fluid. These data support the existence of significant transmural gradients for extracellular purine levels in crystalloid perfused guinea pig hearts. Transmural differences in vasoactive adenosine levels may be partially due to the greater endocardial oxygen consumption and metabolism and may be involved in maintaining relatively high subendocardial blood flows in the face of high intramyocardial pressures.Adenosine may be responsible for modulating myocardial blood flow in response to alterations in oxygen supply and demand (1). This hypothesis predicts a consistent relationship between extracellular adenosine levels and coronary vascular tone or blood flow. In examining this hypothesis, the process of myocardial adenosine formation has been intensively studied (1-4). Unfortunately, most indices of adenosine formation do not directly reflect interstitial adenosine levels-the adenosine pool in direct contact with extracellular receptors. Furthermore, these same indices only reflect global changes in adenosine levels and cannot detect regional differences in extracellular adenosine. The mammalian myocardium is a heterogeneous tissue and the subepicardial and subendocardial regions differ physically, metabolically, and functionally (5-10). Little information is available regarding spatial heterogeneities in extracellular metabolite levels. Interestingly, recent studies indicate that transmural differences exist in the distribution of adenosine-regulating enzymes (11) and it has been demonstrated that transmural gradients exist for intracellular adenosine during control perfusion and ischemia in vivo (12). Thus, it is possible that physiological messengers such as adenosine may be unevenly distributed throughout the myocardial interstitial space.Recently, different methods have been developed for sampling interstitial transudate on the epicardial surface of the myocardium (13)(14)(15)(16)(17)(18). In the present study, we measured epicardial and endocardial transudate concentrat...

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Intracapillary hemoglobin oxygen saturation and oxygen consumption in different layers of the left ventricular myocardium

Cited by 51 publications

References 31 publications

High energy phosphate stores and lactate levels in different layers of the canine left ventricle during reactive hyperemia.

High energy phosphate stores and lactate levels in different layers of the canine left ventricle during reactive hyperemia.

Thyroxine-induced hypertrophy of the rabbit heart. Effect on regional oxygen extraction, flow, and oxygen consumption.

Transmural distribution of extracellular purines in isolated guinea pig heart.

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