Torsade de pointes associated with hypokalemia after anthracycline treatment in a patient with acute lymphocytic leukemia

Severe dose-dependent anthracycline cardiotoxicity is reported to cause myo cardial damage resulting in congestive heart failure. However, torsade de p ointes, a life-threatening arrhythmia caused by chronic anthracycline cardi otoxicity, has not been reported previously. A 16-year-old girl who develop ed torsade de pointes after 6 months of chemotherapy for acute lymphocytic leukemia (French-American-British classification L2) is described. When the patient was readmitted to the hospital because of syncope, peripheral bloo d and bone marrow analysis indicated a relapse. In addition, the patient wa s hypokalemic. Twenty-four-hour ambulatory electrocardiographic monitoring demonstrated QT prolongation and an episode of torsade de pointes. The elec trocardiographic changes and arrhythmia improved after correction of the hy pokalemia. An inverse correlation between leukocyte count and hypokalemia w as observed. The patient died from pulmonary hemorrhage. Autopsy examinatio n demonstrated myocardial degeneration consistent with damage induced by an tineoplastic antibiotics. The cumulative dose of anthracycline and anthraqu inone was less than the conventional dose limit associated with chronic car diotoxicity, even for children who are more sensitive to anthracyclines. To rsade de pointes can occur in the setting of chronic anthracycline cardioto xicity. Therefore, children or young adults who are more sensitive to anthr acycline need careful observation that includes electrolyte monitoring, esp ecially for potassium. (C) 2000 The Japanese Society of Hematology.