Acute myocardial effects of mitoxantrone in the rabbit

Some clinical studies that were performed for the purpose of assessing the potential cardiotoxicity of mitoxantrone (DHAD) have shown that repeated administrations of the drug in some patients cause a mild impairment of cardiac functions and morphological changes in the myocardial cells qualitatively similar to those elicited by anthracyclines. Since doxorubicin has been reported to cause acute cardiac effects, probably related to its chronic cardiotoxicity, experiments were carried out on the rabbit heart to investigate whether DHAD is also able to induce acute cardiac effects. Our results show that this drug caused a reversible dose-related impairment of cardiac contractility on the isolated and perfused rabbit heart while it was not able to induce ECG alterations in normal rabbits. These findings demonstrate that in the rabbit DHAD induces an acute cardiac activity qualitatively similar to that of doxorubicin and suggest that this animal model could be a useful tool to study the cardiac actions and related pathogenetic mechanism(s) of this antitumor drug.