Reduced aerobic metabolic efficiency in globally "stunned" myocardium

Steven B. Laster, Lewis C. Becker, Guiseppe Ambrosio, William E. Jacobus

Research output: Contribution to journalArticlepeer-review

Abstract

Post-ischemic "stunned" myocardium appears to be metabolically inefficient, since oxygen consumption is preserved, while mechanical work is depressed. The present study investigated whether this metabolic inefficiency represents a basal functional abnormality present in the quiescent myocardium (e.g. abnormal mitochondrial coupling) or is specifically related to muscle contraction. Isolated perfused rabbit hearts (n = 7) were exposed to 20 min zero-flow ischemia to produce post-ischemic myocardial stunning. After 10 min of reperfusion, mean rate-pressure product (mmHg/min), was reduced to 56.1% of baseline in stunned hearts, while mean oxygen consumption (μmol O2/min/g LV) was reduced to only 71.8% of baseline. The ratio of oxygen consumption to rate-pressure product remained significantly elevated throughout 40 min of reperfusion when compared with non-ischemic controls (P < 0.01). Despite inappropriately high oxygen consumption in the beating stunned heart, basal oxygen consumption measured after KCl arrest was not significantly different from controls (1.07 ± 0.07 vs. 1.03 ± 0.04, respectively). These results indicate that the metabolic inefficiency found in stunned myocardium is not a basal abnormality, but rather is related specifically to abnormalities in contraction or electromechanical coupling.

Original languageEnglish (US)
Pages (from-to)419-426
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume21
Issue number4
DOIs
StatePublished - Apr 1989

Keywords

  • Cardiac contraction
  • Cardiac work
  • Ischemia
  • Myocardial oxygen consumption
  • Reperfusion
  • Stunned myocardium

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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