Automating the selection of expansion modes using the principal components of time method for solving the inverse problem of electrocardiography

A common approach for estimating epicardial potentials from measured body sutface potentials is to solve the problem using some type of regularization at each point in time independently. Greensite and Huiskamp huve previously proposed a solution based on expanding the solution in the principle time components of the data. However; their proposed method did not indicate how many modes to use in this expansion, or indicate how to automate it. In this paper; we examined an automated solution to this problem. This automated procedure was applied to data obtained during a study on swine. For first order Ekhonov regularization, the new method produced an averuge relative error of 0.56 over all six depolarization sequences, compared with 0.61 for the traditional approach. While the new automated method is not necessarily optimal, it does consistently produce smaller relative errors than the traditional approach.