[Electrocardiography in pediatrics. 2: Recommendations for a newly introduced recording and evaluation procedure].

ECG recordings were made by means of a modified NELSON-lead system in a total of 100 children aged between 2 weeks and 59 months. Software developed by ourselves served for on-line calculations of the dipole moment D which is graphically represented by vector loops in three projection planes, horizontal, frontal and sagittal. In addition, the maximum spatial vector Dmax and the mean vector A are calculated by the program. The examination of one child including positioning of 20 electrodes and production of a hard-copy of the results takes no longer than 15 minutes. The children were unsedated and awake when the ECGs were recorded. The results show the continuously growing dipole moment and its gradually changing direction from the right posterior or left anterior to the left posterior quadrant in parallel with the growth of the body and the heart, respectively. The smallest vector magnitudes and smallest vector loops of the dipole moment are measured in the youngest infants (0-2 months) while very high voltages in conventional ECGs of infants are regularly seen, predominantly in the precordial region. Two examples of pathological NELSON-ECGs are reported. One case is a boy aged 4 years 10 months with aortic supravalvular stenosis, the other one is a girl aged 4 years 3 months with pulmonic valve stenosis. These cases demonstrate the excellent suitability of this noninvasive method as a diagnostic tool for pediatric cardiology.