THE VECTORCARDIOGRAM IN NORMAL CHILDREN

Abstract

Eighty-four Frank system vectorcardiograms of normal children aged 2 to 12 years were analysed. The directions of the initial and terminal 5-millisecond QRS vectors were widely scattered in the frontal plane but were closely grouped in the sagittal and horizontal planes. The directions of the 0-04-second and the maximum vectors did not always follow a normal distribution but were well enough delineated in the, horizontal plane to be of diagnostic value. The 0.02-second vector, A QRS, and the maximum T vector in all planes were narrowly enough distributed to be clinically significant. The rotation of the QRS loop in the horizontal plane was mostly counterclockwise, although in a small minority the loop showed a figure-of-eitht pattern with the returning limb intersecting the midline posterior to the E point. This parameter, which shows a distinct evolution with age, appears to be of considerable diagnostic value. The method of mean QRS axis determination used in this study was comparable to the half-area method and was simpler to use.