Anthracyclines are cytotoxic drugs featuring cardiotoxicity as one of most prominent undesirable effects, which occurs in both its acute or cumulative from. The acute from of cardiotoxicity has been subject of much less concern although some sudden deaths have been reported during anthracycline administration (Wortman et al. Cancer 44; 1979). The present study involved 36 patients with soft tissue sarcomata, 28 with non-Hodgkin's lymphomas, 23 with nasopharyngeal carcinomas, 5 with carcinoma of the lungs, and 7 breast carcinoma patients (99 patients in total) who were treated with anthracyclines. Zorubicin was given to 40 patients, doxorubicin to 21, epidoxorubicin to 20, adn mitoxantron to 18 patients. Control groups were made of 29 patients who did not receive any anthracyclines and those who were treated with anthracyclines for the first time. In addition, as a third group, each patient was his/hers own control. All patients were subject to continuing ECG monitoring by using a Delmar Avionics Stratscan holter ECG monitor. In the course of intravenous infusion of anthracyclines, irregularities of heartbeat occurred in the form of sinus tachycardia and atrial (AEBs) and ventricular ectopic beats (VEBs). In relation to the control, the number of VEBs increased to level III of the Lown's scale while administering zorubicin, and then receded after the infusion. The number of AEBs remained steady or even increased for a certain while after administration of the drug. These irregularities were most prominent during the first administration of anthracycline. However, all registered changes are reversible and neither make a hindrance to therapy, nor necessitate cessation of anthracycline administration. A sporadic occurrence of VEBs at level III according to the Lown's scale point out to a possible occurrence of more severe rhythm disorders.

Keywords: doses, mode of administration, Holter-ECG, cardiotoxicity, Anthracyclines