OBJECTIVETo evaluate the effect of tetra-arsenic tetra-sulfide (As4S4) therapy on the corrected QT interval (QTc) in the acute promyelocytic leukemia (APL) patients.

METHODSNinety cases of APL treated with As4S4 were divided into two groups--the remission induction group and maintenance therapy group. Blood arsenic concentration was measured and a 12-lead electrocardiogram (ECG) was simultaneously performed before treatment and after remission in the induction group, and before and 2, 4, 6, 8, 10 courses after the treatment in the maintenance therapy group. QT interval on each ECG was measured and corrected by the Bazett formula.

RESULTSOral administration of As4S4 could lead to the prolongation of QTc both in remission induction and maintenance therapy groups. QTc prolongation was related to the doses of As4S4 and blood arsenic levels. QTc prolongation and its variation range were increased with accumulative doses of As4S4 and the blood arsenic levels. In ten courses maintenance therapy patients, the average abnormal rate of QTc was 37.7%. Blood arsenic concentration was increased slowly with courses, but the variation had no statistical difference (P > 0.05). All the patients whose QTc was abnormal (> or = 440 ms) had neither symptoms nor serious cardiac events, such as ventricular tachycardia and Torsade de pointes and could complete the As4S4 therapy.

CONCLUSIONAlthough As4S4 therapy can lead to QTc prolongation in the treatment of APL patients, it does not preclude the completion of the therapy.