A report on pathological changes of the dipole moment in children suffering from anthracycline cardiomyopathy

Cardiomyopathy is a severe complication of the tomour therapy with anthracyclines. Since even minor disturbances of myocardial cell membranes could influence the dipole moment of the heart the noninvasive measurements of this parameter might be useful, particularly in the paediatric population. 17 children aged 2-15 years treated clinically for various malign blood diseases were examined repeatedly with a modified Nelson lead-system up to 3 years. The dipole moment was evaluated by visual comparison of the calculated horizontal and frontal VCGs, evaluation of 3 distinctive vectors, as well as of the magnitude curves and the velocity curves, all of them compared with the normal age dependent percentiles of each respective child. Conventional 12-lead ECGs were used to confirm rhythm disturbances and alterations of P-, PQ-, QRS-, and QT-durations. Our results show that damages of the heart are different during the time of the drug administration, then consisting of acute toxic reactions such as sudden dilatation and/or rhythm disturbances, and of long-term disturbances leading to growth retardation of the heart with the danger of chronic congestive heart failure months or years after the end of the anthracycline treatment. Morphological and biochemical damages of myofibrils caused by the toxicity of anthracyclines precede functional restraints of the heart. A noninvasive method for an early and reliable diagnosis of these damages is urgently needed, particularly for children. Measurements of the dipole moment with the Nelson-lead system seem to offer this diagnostic tool which aims possible changes of the drug administration protocol. (Fig. 3, Ref. 15.)