[Thalidomide-associated bradycardia in patients with hematologic diseases: a single institution experience]

Thalidomide, an immunomodulatory and antiangiogenic agent, is useful in the treatment of some hematologic and oncologic diseases. Up to 6.8% of thalidomide-treated patients present bradycardia. Herein the incidence of thalidomide-associated bradycardia in patients with hematologic diseases treated in a single institution is reported. In a 34-month period, 33 patients with different hematologic diseases (multiple myeloma [MM], 20; myelodysplastic syndrome, eight; Waldenström macroglobulinemia, two; non-Hodgkin's lymphoma, two; malignant histiocytosis, one) were treated with thalidomide. Of them, five (15.1%) had bradycardia, all with MM. Bradycardia was detected with a daily thalidomide dose ranging from 100 to 300 mg and the time patients received thalidomide before cardiac event went from one to 18 months. In all affected cases the electrocardiogram showed sinus bradycardia with cardiac frequency between 32 to 48 beats per minute. Time to normal cardiac beat recovery ranged from 12 to 21 days after thalidomide discontinuation. There were no fatalities due to thalidomide-associated bradycardia. It is concluded that: a) thalidomide-associated bradycardia was detected only in patients with MM, b) herein the incidence of bradycardia was higher as compared with other series, and c) in patients with MM thalidomide therapy must be prescribed with caution particularly in those with cardiovascular diseases of any etiology.