Effects of Methylprednisolone Sodium Succinate on Myocardial Performance, Hemodynamics and Metabolism in Normal and Failing Hearts.
OKLAHOMA UNIV HEALTH SCIENCES CENTER OKLAHOMA CITY
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The purpose of the study was to evaluate the effects of methylprednisolone sodium succinate, 30 mgKg, on myocardial performance, hemodynamics and oxidative metabolism. Experiments were carried out on normal and endotoxin-treated hearts in the intermediate phase of shock 4-8 hours. The isolated working canine left ventricle, exchanging blood with an anesthetized support animal, was subjected to standardized afterload stresses under conditions of constant cardiac output and blood temperature. Results demonstrated a positive inotropic action of the steroid increased dPdt, lowered left ventricular end diastolic pressures, increased coronary blood flow, decreased coronary vascular resistance and enhanced oxygen delivery of myocardial tissue. These beneficial effects were primarily evident in normal hearts and in a large percentage of the endotoxin heart failure preparations, designated Group 1 hearts. In other instances heart failure after endotoxin was either unmodified, or worsened, by the use of the steroid Group 2 hearts. The mechanisms of action of the steroid on the heart seem to invoke a beneficial linkage between myocardial perfusion, oxygen availability, and contractility. The use of steroids may be contraindicated in some severely failing hearts, as suggested in the present study, and in these instances digoxin was demonstrated to be superior as an effective therapeutic agent. Author