This research has the following components: 1. Correlation of Body Surface Potential Maps (based on potentials recorded from 180 electrode sites) with cardiac physiology and pathology in pediatric patients utilizing non-ECG diagnostic data derived from catheterization and echocardiographic measurements, as well as standard ECG and VCG recordings. Over 60 normal and congenital heart defect patients have been screened and reviewed. Diagnostic criteria are being developed. 2. Studies and development of new methods for improved display and recording (storage) of maps for pattern recognition and classification. To date maps are generated in 36 levels of pseudo-color and are presented in groups of six along with vector loops and magnitude functions. 3. Normalization of maps to eliminate the effect of body shape and surface inhomogeneities and to enhance spatial contrast by inward transformations (e.g., to the epicardium). We have now demonstrated that the epicardial map is, itself, normalized. Consequently we are currently directing biophysical studies to this goal. 4. Improve applications of technology to simplify application of electrodes to the body and the electronics necessary to produce quality (low-noise) maps. A vest carrying active dry electrodes has been developed and is working fairly well. The vest is undergoing redesign. We are also experimenting with passive electrodes with the active elements at the termination of short cables to reduce cost of duplicating the vest. A new lower noise system involving early A-D and digital storage is under construction.