LATE EFFECTS OF ANTHRACYCLINE THERAPY IN CHILDHOOD IN RELATION TO THEFUNCTION OF THE HEART AT REST AND UNDER PHYSICAL STRESS

To evaluate the long-term effects of anthracyclines on the myocardium of the young child we examined 34 patients who had been treated with a nthracyclines in childhood. In addition to anthracycline, the patients were treated with other potentially cardiotoxic substances within the framework of different protocols. The mean cumulative anthracycline d ose was 128.6 mg/m(2), the average age at onset of chemotherapy 4.2 ye ars, and the time interval after discontinuation of treatment 9.0 year s. The cardiological examination consisted of a physical examination, electrocardiography and echocardiography, including Doppler and bio-im pedance cardiography. The patients were studied at rest and after phys ical exercise with a cycle ergometer test in a supine position. The re sults of the physical examination, the electrocardiogram at rest and t he 24 h Holter monitoring were normal. The left ventricular enddiastol ic diameter, shortening fraction, velocity of fibre shortening (VCF), the diastolic flow profile at the mitral valve level and the cardiac s troke volume at rest were also normal, However, the shortening fractio n (SF) was below the margin of 2 standard deviations in two patients a nd the VCF in three patients. There was a significant reduction in sep tal thickness, (-1.4 SD, P < 0.0004), in the width of left ventricular posterior wall(-1.5 SD, P > 0.0002) and in the left ventricular myoca rdial mass (-0.76 SD, P = 0.0042). Physical working capacity was norma l. Immediately after physical stress the expected rise of SF and VCF d id not occur and the SI: fell below the values at rest. In comparison to a healthy control group the SF and the VCF were markedly decreased (P > 0.0001). The stroke volume decreased by 14 % compared to the pre- exercise value. Conclusion Chemotherapy with anthracyclines, even in l ow dosages, results in myocardial damage, which does not however, effe ct physical capacity over a long period but which is revealed by reduc ed left ventricular wall thickness and myocardial mass. Functional eff ects include insufficient increase of SE VCF and stroke volume during physical exercise.