Frank vectorcardiograms during the first year of life: a longitudinal study of 62 healthy children.

A longitudinal vectorcardiographic study of 62 healthy children was carried out at the ages of one and six days and 1, 2, 4, 6, 9, and 12 months. Recordings were made using the Frank x, y, and z leads and the equipment developed by Arvedson [2]. In each age group 25 spatial vectors were examined. Planar projections of 13 timed QRS vectors were presented as mean QRS loops in the main planes. The results were in agreement with earlier studies but gave a more accurate representation of cardiac activation. The maximal spatial vectors to the right and to the left, the 0.035 and 0.04, the mean QRS and the partial mean 2/3 QRS vectors clearly reflected a decrease in right ventricular dominance during the first two months and an increase in left ventricular dominance during the first year. Vectorcardiographic development in each child, from the newborn pattern onward, occurred individually. None of the 12 vectors examined on 22 children from whom there were recordings in each age group from one day to nine months by the Spearman rank correlation test revealed any significant correlation.