Early and late arrhythmogenic effects of doxorubicin

BACKGROUND: To determine the incidence of early and late arrhythmogenic effects of doxorubicin-containing chemotherapy regimens. PATIENTS AND METHODS: A prospective study including 29 patients who were treated with doxorubicin-containing regimens. Cardiac evaluation was based on 24-hour electrocardiographic monitorization (Holter), which was performed during the first cycle of doxorubicin-containing regimens, as well as after the last cycle of chemotherapy. RESULTS: The mean age of the patients was 45.8 ± 15.1 (range 18-69). Holter records obtained during the first cycle of treatment revealed varying arrhythmias in 19 patients (65.5%) and in 18 (62.1%) patients after completion of therapy. One patient presented with syncope and both Mobitz Type 2 atrioventricular block and complete atrioventricular block were demonstrated. The patient subsequently underwent permanent pacemaker implantation. CONCLUSIONS: Doxorubicin may result in arrhythmias both in early and late periods of treatment. These arrhythmias are rarely life threatening.