Selenium as a protector of diastolic function during oxidant stress.

Interventional studies yielded conflicting results on reperfusion injury. They are unable to discriminate between lesions due to ischemia or to additional damage during reoxygenation. Since reactive oxygen metabolites have been implicated as a major cause of reperfusion injury, 375 nmol/min of hydrogen peroxide was infused in a Langendorff rat heart preparation as a model of oxidant stress without previous ischemic contractile dysfunction. Impaired endogenous defense was remodeled, using selenium-deficient hearts with reduced glutathione peroxidase activity. Measurements of hemodynamic parameters demonstrate increased myocardial susceptibility to oxidant stress in hearts with decreased antioxidant defense. Defined concentrations of hydrogen peroxide produce isolated impairment of active and passive diastolic properties of the ventricle in this model.