Abstract

Aim: Prolonged QT dispersion (QTD) and corrected QT dispersion (QTcD) have been associated with serious arrhythmias and sudden death in many forms of heart disease, including childhood leukemia. The purpose of this study was to determine the possible cardiac adverse effects of anthracycline treatment on corrected QT dispersion (QTcD) in patients with leukemia who were on therapy and who had completed the therapy. Methods: The QT dispersion was evaluated in 24 (43.6%) female ond 31 (56.4%) male patients with acute lymphoblastic leukemia whose mean age was 8.8 ± 4.2 years. Mean duration of follow-up was 34.1 ±21.0 (range 1-80) months. The cumulative anthracycline dose was determined for each patient and expressed as milligrams per square meter. Serum levels of electrolytes, proteins, thyroid function tests, and electrocardiograms (ECG) were evaluated simultaneously. The measures of dispersion for QT interval (QTD) and for QTc interval (QTcD) were accepted as differences between the maximum and minimum QT and QTc intervals, respectively, and measured in 12 lead in each ECG. SPSS 10.0 for Windows was performed for statistical analysis. Comparisons between groups of patients were done using Students two-tailed t test and Kruskall-Wallis test. Statistical significance was taken to be a p value < 0.05. Results: The patients still on treatment (n: 21) and the patients in remission were compared. The differences were found only in QT interval and albumin levels (0.31 ± 0.04 versus 0.34 ± 0.04, p: 0.009 and 3.7 ± 0.6 ver sus 4.2 ±0.5, p-.O.Ol, respectively). In the children who had taken cumulative anthracycline dose <250 mg/m2 (m 44) and >250 mg/m2 (n: 11), there were no difference in electrocardiographic measurements but there were difference in serum globulin levels (2.7 ± 0.5 versus 3.2 ± 0.9 p: 0.02, respectively). Conclusion: No remarkable cardiotoxicity of chemotherapy protocols (ALL BFM 95 and TRALL 2000) is detected in electrocardiographic evaluation of the leukemic children both on therapy and during remission for average three years. However, further monitoring and evaluation with such sensitive and non-invasive methods should be done for longer periods.