For the early detection of myocardial damage associated with anthracycline therapy, electrocardiography, echocardiography, and radionuclide angiocardiography were used to assess cardiac function in 37 patients receiving anthracyclines (ie, adriamycin and daunorubicin at a total dose of 100-2,030 mg/m2). None of the patients developed clinical congestive heart failure. There were no significant changes of electrocardiographic and echocardiographic parameters after anthracycline administration. The left ventricular ejection fraction did not change significantly on radionuclide angiocardiography. However, the 1/3 peak filling rate (PFR) corrected by the end-diastolic count (EDC) (1/3 PFR/EDC) and the 1/3 filling fraction (1/3 FF), the indices of early diastolic function, showed a significant decrease. These findings suggest that the 1/3 PFR/EDC and 1/3 FF determined by radionuclide imaging are useful for detecting silent myocardial damage induced by anthracyclines.