AbstractThe protective effects of lidoflazine and mioflazine against normothermic ischemia were evaluated in isolated rabbit hearts used in the working mode. Pretreatment with 0.125 mg\liter of these drugs improved recovery of cardiodynamic function during postischemic reperfusion. Functional recovery was preceded by less severe impairment of sarcolemmal structure and Ca2+distribution at the end of the ischemic period, allowing the normalization of other substructures and the prevention of cellular Ca2+overload during postischemic reperfusion. When cardiac output and semi‐quantitative histology are taken as parameters, the protective effects of mioflazine were greater than that of lidoflazin