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Deleterious effect of ouabain on myocardial function during hypoxia
M J Cunningham1, C S Apstein, E O Weinberg
1Cardiac Muscle Research Laboratory, Cardiovascular Institute of Boston University School of Medicine, Massachusetts.
The American Journal of Physiology
|March 1, 1989
Summary
Cardiac glycosides like ouabain worsen heart function during low oxygen (hypoxia). This study found ouabain impairs left ventricular performance and recovery after reoxygenation in isolated rabbit hearts.
Area of Science:
- Cardiovascular Physiology
- Cardiac Pharmacology
Background:
- The impact of cardiac glycosides on myocardial function under hypoxic conditions remains debated.
- Ouabain is a cardiac glycoside with inotropic effects.
Purpose of the Study:
- To investigate the effects of a non-toxic dose of ouabain on isolated rabbit heart function during hypoxia and reoxygenation.
- To determine if ouabain alters left ventricular performance, diastolic distensibility, and recovery post-hypoxia.
Main Methods:
- Isolated, isovolumic, buffer-perfused rabbit hearts were used.
- Hearts were subjected to 15 minutes of hypoxia followed by reoxygenation.
- Ouabain was administered at a mildly inotropic, non-toxic dose.
Main Results:
- Ouabain significantly reduced left ventricular developed pressure during hypoxia compared to controls.
- Left ventricular end-diastolic pressure increased more with ouabain during hypoxia, indicating reduced diastolic distensibility.
- Recovery of developed pressure and normalization of end-diastolic pressure were impaired upon reoxygenation in the ouabain group.
Conclusions:
- A modest dose of ouabain exacerbates hypoxia-induced decreases in diastolic ventricular distensibility.
- Ouabain worsens the decline in developed pressure during hypoxia and impairs cardiac recovery after reoxygenation.