Prolongation of the QT interval and ventricular tachycardia in patients treated with arsenic trioxide for acute promyelocytic leukemia

Background: Recently, arsenic trioxide has increasingly been used for relapsed acute promyelocytic leukemia, However, it is known to have several adverse effects, including acute cardiac toxicities. Objective: To determine cardiac toxicities resulting from arsenic trioxide therapy in patients with relapsed or refractory acute promyelocytic leukemia. Design: Phase II clinical prospective cohort study. Setting: A university hospital in Hamamatsu, Japan. Patients: 8 patients with relapsed acute promyelocytic leukemia Intervention: Arsenic trioxide, 0.15 mg/kg of body weight, administered daily by 2-hour infusion for a maximum of 60 days, Measurements: Continuous monitoring with ambulatory electrocardiography, Results: Five patients (63%) achieved complete remission. During induction therapy with arsenic trioxide, prolonged QT intervals were observed in all patients. Ventricular premature contractions were noticed during 8 of 12 courses of therapy. Four patients developed nonsustained ventricular tachycardia and required treatment with antiarrhythmic agents. Conclusions: Cardiac toxicity occurs during arsenic trioxide therapy in patients with acute promyelocytic leukemia. Such patients should be monitored for prolonged QT intervals and ventricular arrhythmia.