Noninvasive electrical imaging of the heart: Theory and model development

The aim of this work is to begin quantifying the performance of a recently developed activation imaging algorithm of Huiskamp and Greensite [IEEE Tran s. Biomed. Eng. 44:433-446]. We present here the modeling and computational issues associated with this process. First, we present a practical constru ction of the appropriate transfer matrix relating an activation sequence to body surface potentials from a general boundary value problem point of vie w. This approach makes explicit the role of different Green's functions and elucidates features (such as the anisotropic versus isotropic distinction) not readily apparent from alternative formulations. A new analytic solutio n is then developed to test the numerical implementation associated with th e transfer matrix formulation presented here and convergence results for bo th potentials and normal currents are given. Next, details of the construct ion of a generic porcine model using a nontraditional data-fitting procedur e are presented. The computational performance of this model is carefully e xamined to obtain a mesh of an appropriate resolution to use in inverse cal culations. Finally, as a test of the entire approach, we illustrate the act ivation inverse procedure by reconstructing a known activation sequence fro m simulated data. For the example presented, which involved two ectopic foc ii with large amounts of Gaussian noise (100 muV rms) present in the torso signals, the reconstructed activation sequence had a similarity index of 0. 880 when compared to the input source. (C) 2001 Biomedical Engineering Soci ety.