Redundancy Reduction for Improved Display and Analysis of Body Surface Potential Maps: I. Spatial Compression

The Karhunen-Loeve technique of random process representation was investigated as 97 patients with independently documented heart disease were used in the study. Each map frame in QRS and ST-T of 34 maps in a test set was represented as a linear sum of orthonormal distributions derived from the covariance matrix estimated from all QRS frames in the 221 training maps. A 16:1 reduction spatial data of test set was achieved with rms errors of 45 and 21 pV in QRS and ST-T, respectively. Results suggest that 12independent waveforms, derived from the 192 measured ECGs, may be used in place of those ECGs. In addition to providing a convenient and familiar method of display for map data, the technique puts the data in an appropriate form for quantitative statistical analysis.