[Cardiotoxic study of aclacinomycin A: Acute cardiotoxic effect of aclacinomycin A in hamsters (author's transl)].

: The Third Department of Medicine, Tokyo Medical and Dental University Medical School The cardiotoxic effect of aclacinomycin A or adriamycin given by a single intravenous injection was evaluated in golden hamsters by electrocardiography (ECG) and electron microscopy. Aclacinomycin A caused slight ECG alterations at a dose of 75 mg/kg or 100 mg/kg such as bradycardia, Ta wave formation, ST segment depression and T wave flattening. On the other hand, adriamycin caused moderate to remarkable alterations in ECG at a dose of 3.13 mg/kg or 6.25 mg/kg, such as arrhythmia, bradycardia, auriculoventricular block, bundle branch block, ST segment changes and T wave flattening. Alterations in ultrastructure of the myocardium caused by aclacinomycin A at a dose of 25 mg/kg contained some cardiac cells with mild changes, ie, dilations of sarcoplasmic reticulum and swelling of mitochondria. At a dose of 100 mg/kg, it caused moderate to remarkable alterations such as separation of myofilaments, appearance of myelin figures, and decreases in intramitochondrial granules and glycogen particles. Adriamycin, however, gave remarkable changes even at a dose of 6.25 mg/kg which involved separation of myofilaments, lower electron-density of mitochondrial matrix, vacuolization and swelling of capillary endothelial cells. From these findings, both antibiotics may cause cardiotoxicity by similar mechanism. But aclacinomycin A affected the heart milder than adriamycin.