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