Protective effect of betamethasone on the subendocardial ischemia after the cardiopulmonary bypass.

The experimental and clinical studies on the protective effect of Betamethasone upon the myocardium particularly on the prevention of the subendocardial ischemia after the cardiopulmonary bypass was investigated on the ultrastructural alterations of the epicardium and the endocardium obtained by the transmural left ventricular myocardial biopsy. Pretreatment of Betamethasone, 5 mg/Kg, with single intravenous injection a half to one hour before cardiopulmonary bypass was effective to preserve the myocardial ultrastructure after the anoxic arrest and in the recovery period after restoring the coronary circulation. The intramyocardial gradient of the ultrastructure was diminished by Betamethasone hardly demonstrating the no-reflow phenomenon. Hemodynamic and metabolic changes did not show the significant effectiveness of Betamethasone. It was suspected that Betamethasone stabilized the cell membrane and lysosome and suppressed the interstitial edema in the myocardium during and after anoxic arrest.