Doxorubicin cardiotoxicity. Serial endomyocardial biopsies and systolic time intervals

Abstract

Doxorubicin, whose dose-limiting toxicity is cardiomyopathy, was given to 4 cancer patients. Endomyocardial biopsy specimens and test results of cardiac function were obtained before, during and after treatment. The biopsy specimens were examined by light microscopy EM and were graded blindly. Evidence of specific doxorubicin injury was found in 3/4 patients with as little as 180 mg/m2 of the drug and became progressively more severe with higher doses. All test results of cardiac function, including systolic time intervals, remained normal. A specific, progressive subclinical injury to the heart may occur with doxorubicin therapy, which cannot be reliably detected by routine tests. This potential risk must be taken into account with the use of doxorubicin, especially when combined with synergistic agents.