Recruitment of myocardial work and metabolism in regionally stunned porcine myocardium

E. O. McFalls, D. J. Duncker, R. Krams, L. M.A. Sassen, A. Hoogendoorn, P. D. Verdouw

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

We characterized postischemic changes in myocardial metabolism and regional external work, as measured by the integral of left ventricular pressure-segment-length loops. In 12 anesthetized swine, the left anterior descending coronary artery (LAD) was occluded for 10 min and reperfused for 30 min for two successive cycles. Before ischemia, regional work was 16,920 ± 5,630 mmHg-mm/min and after stunning, work was reduced to 50 ± 14% (P < 0.05). At baseline, oxygen and lactate consumption were 4.80 ± 1.40 and 1.02 ± 0.46 μmol·min-1·g-1, respectively, and after stunning they were reduced to 3.24 ± 0.80 (P < 0.05) and 0.16 ± 0.21 μmol·min-1·g-1 (P < 0.05), respectively. The atria were then paced 50 beats/min higher than the reperfusion heart rate, during and without an infusion of dobutamine (2 μg·kg-1·min-1). During dobutamine, both regional external work and oxygen consumption returned to 98% of preischemic values, but lactate utilization remained depressed. We conclude that regional external work and oxygen consumption remain coupled during inotropic stimulation after stunning, with a preferential shift toward nonlactate substrates.

Original languageEnglish (US)
Pages (from-to)H1724-H1731
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume263
Issue number6 32-6
DOIs
StatePublished - 1992

Keywords

  • dobutamine
  • external work
  • myocardial stunning
  • oxygen consumption

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