Compression of body surface potential maps and estimation of their dynamic changes

Body-surface potential maps (BSPMs) are measured routinely, but their interpretation and display are difficult and slow due to the immense amount of data involved. A data-reduction procedure is presented which conserves spatial details and allows definition of describing indices. A sequence of 350 BSPMs covering a subject´s QRST for one heartbeat is analyzed by thresholding each map. This process reduces the 3-D maps to 2-D shapes, with at least 4:1 data reduction, without loss of spatial resolution. Then the center of mass of the 2-D shape is calculated for each map, and the resultant time-dependent locus of these points is displayed. Ten normals and four patients with Wolff-Parkinson-White syndrome have been studied. The group of loci of the normals has been found to differ significantly from those of the patients. Thus the data-reduction procedure may help identify indices of diagnostic value. The modified maps allow simpler treatment and may assist in popularizing this technique