The inverse problem of electrocardiography: application to localization of Wolff-Parkinson-White pre-excitation sites

Epicardial-surface potential maps (ESPMs) during pre-excitation of the ventricles were constructed from body-surface potential maps (BSPMs) by an inverse solution. Forward transfer matrix was derived by using Green's theorem and boundary element method (BEM); to invert the matrix, Tikhonov regularization using a Laplacian operator and L-curve selection of regularizing parameters were used. The authors present BSPMs and ESPMs for eight pre-excitation sites at 30 ms into the delta wave. Locations of minima on ESPMs correspond to the pre-excitation sites. Locations of maxima and minima compare well with recorded data from primates and humans. These results demonstrate the accuracy of the authors' inverse solution and its usefulness in clinical applications.