Assessment of Early-Onset Chronic Progressive Anthracycline Cardiotoxicity in Children: Different Response Patterns of Right and Left Ventricles

We aimed to assess early-onset chronic progressive cardiotoxicity in the left and right ventricles with increasing cumulative anthracycline doses. We evaluated 72 patients within the first year after doxorubicin and/or daunorubicin treatment (median 1.3 months; range 0.3–11.5) and 31 healthy controls. Pretreatment and posttreatment QT interval analyzes were performed in 27 newly diagnosed patients. The echocardiographic data of all examinations of 72 patients were classified into three groups according to instant cumulative anthracycline doses: treatment group (TG)-I (≤120 mg/m²; n = 26), TG-II (120–240 mg/m²; n = 39), and TG-III (≥240 mg/m²; n = 40). Diastolic and systolic parameters were analyzed by conventional echocardiography and tissue Doppler imaging (TDI) and compared with those of healthy controls. The mean age for patients and controls was 8.2 ± 4.5 and 9.6 ± 4.2 years, respectively (p > 0.05). QTc dispersion significantly increased after anthracycline treatment (p = 0.02). TDI showed decreased E′ velocity (p < 0.001) and E′/A′ ratio (p < 0.001) at lateral tricuspid annulus segment in TG-I, and these findings continued in TG-II and -III. In addition, S′ velocity decreased in TG-I, -II, and -III at lateral mitral annulus (10.5 ± 2.6 cm/s, p < 0.05; 9.9 ± 2.2 cm/s, p < 0.001; and 10.1 ± 2.3 cm/s, p < 0.01, respectively). However, decrease in left-ventricular ejection fraction was statistically significant in TG-II and -III (p < 0.001). Although myocardial performance index was significantly increased in all treatment groups in both segments, it was primarily due to significant increases in isovolumic relaxation time at the lateral tricuspid annulus and isovolumic contraction time at the lateral mitral annulus. Abnormalities in diastolic function in right ventricle and systolic function in the left ventricle were observed even with a cumulative anthracycline dose <120 mg/m² by TDI. In addition, anthracycline treatment led to an increase in QTc dispersion.