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 myocardial damage resulting in congestive heart failure. However, torsade de pointes, a life-threatening arrhythmia caused by chronic anthracycline cardiotoxicity, has not been reported previously. A 16-year-old girl who developed 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 blood and bone marrow analysis indicated a relapse. In addition, the patient was hypokalemic. Twenty-four-hour ambulatory electrocardiographic monitoring demonstrated QT prolongation and an episode of torsade de pointes. The electrocardiographic changes and arrhythmia improved after correction of the hypokalemia. An inverse correlation between leukocyte count and hypokalemia was observed. The patient died from pulmonary hemorrhage. Autopsy examination demonstrated myocardial degeneration consistent with damage induced by antineoplastic antibiotics. The cumulative dose of anthracycline and anthraquinone was less than the conventional dose limit associated with chronic cardiotoxicity, even for children who are more sensitive to anthracyclines. Torsade de pointes can occur in the setting of chronic anthracycline cardiotoxicity. Therefore, children or young adults who are more sensitive to anthracycline need careful observation that includes electrolyte monitoring, especially for potassium.