Serial assessment of ventricular function by means of radionuclide angiography was performed in previously untreated patients with lymphoproliferative diseases who received either 4'epidoxorubicin or mitoxantrone for longer than 6 months. No changes were observed in left ventricular function in patients received mitoxantrone at doses ranged 90 to 165 mg (mean 113 mg). Three patients (7%) in 4'epidoxorubicin group showed less than or equal to 10% drop in left ventricular ejection, but without clinical manifestations. The doses in this group were 420 to 810 mg (mean 610 mg). We felt that patients without high-risk factors (radiotherapy to mediastinum or previously anthracycline therapy) could be treated with high doses of both drugs and that radionuclide angiography is a useful method for monitoring cardiotoxicity of antineoplastic drugs.