It is shown that 2-chloroethoxy-para-N-dimethylphosphorylacetohydrazide and N-acethylhydrazide-para-dimethylaminophenyl-2-chloroethoxyphosphorylacetic acid reliably reduce ischemia-induced depression of inotropic functions of the left ventricle in cats with experimental myocardial infarction model. The effect of both compounds can be explained by the maintenance of viability of the injured myocardium via a delay of the development of acidosis and the support of oxygen recycling in the ischemized zone. Both compounds show pronounced antiradical properties with a non-standard mechanism of action.