1991
DOI: 10.1161/01.res.69.6.1458
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Active downregulation of myocardial energy requirements during prolonged moderate ischemia in swine.

Abstract: We studied the effects of rapid atrial pacing during the final 10 minutes of a 70-minute, 31% reduction in coronary blood flow in anesthetized swine to understand the significance of apparent metabolic improvements during the initial 60 minutes of segmental ischemia. Within 5-10 minutes of ischemia, subendocardial phosphocreatine (PCr) and ATP were depleted to 47% and 63% of control, respectively; lactate accumulated within the subendocardium to 300% of control; and net arteriovenous lactate production occurre… Show more

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Cited by 101 publications
(43 citation statements)
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“…3 and 4). These simulated results also agree with experimental studies by other researchers (7,65). Comparison of model simulations from current multidomain and previous one-domain models (59) show a great improvement in predicting the dynamics of glycolysis and lactate uptake during ischemia with our new multidomain model.…”
Section: Discussionsupporting
confidence: 87%
“…3 and 4). These simulated results also agree with experimental studies by other researchers (7,65). Comparison of model simulations from current multidomain and previous one-domain models (59) show a great improvement in predicting the dynamics of glycolysis and lactate uptake during ischemia with our new multidomain model.…”
Section: Discussionsupporting
confidence: 87%
“…The direct measurements of aerobic metabolic fluxes in myocardial regions at submilliliter resolution in the present study after half an hour of ischemia show downregulation of aerobic metabolic rates, conforming with the report by Arai et al (3). In the present study, oxygen extraction determined in submilliliter regions was lower during stenosis than in controls (Table 3).…”
Section: Discussionsupporting
confidence: 93%
“…On the other hand, flow heterogeneity observed in epi-, mid-, and endomyocardium as well as during the different phases of the contraction cycle of hypertrophied hearts subjected to low-flow I tends to disappear in nonhypertrophied hearts (5). Also, this problem may be less important in Langendorff-perfused hearts than in other models because of the intraventricular balloon that induces isovolumic contractions and the fixed CF during I and H. However, we cannot rule out the possibility that downregulation of muscular activity during I was the result not only of lactate accumulation (see below) but also of nonuniform muscle perfusion so that some regions were nonperfused to maintain perfusion in others (22).…”
Section: Resultsmentioning
confidence: 95%
“…This difference is amplified in our work because of the severe dysoxia and the-lack of blood 0, buffering capacity. It is difficult to assess from the present data whether the high Pvo during I results from vascular collapse leading to a fesser exchange area and lower 0, diffusive conductance (22) or rather from "metabolic arrest" (19). In our experiments, however, the extra workload caused by pacing did not alter Pv 02' implying that eith .er the metabolic arrest was insen sitive to pacing or that the primary limitation in I was at the level of the microcircul .ation som ,ehow supporting the former hypothesis.…”
Section: Resultsmentioning
confidence: 98%