Dongpu Liu

A Potential Gradient Estimation on the Heart Surface

March 11, 1998
3:30 PM
206 Egan

Abstract

The goal of this work is to develop methods to estimate the surface gradient of electrical potential on the heart surface based on scattered measurements of locations and potentials on the surface. Potential gradients on the heart surface contain important information about the location of cardiac wavefronts. In addition they could be used as a constraint in inverse solutions which estimate cardiac electrical activity based on body surface measurements and a model for the torso volume conductor.

In this project two main technologies are adapted to estimate the potential gradient on the heart surface: surface harmonic expansions and the modified Shepard's interpolation method. First, a surface harmonic expansion method is used to interpolate the irregular heart surface based on the irregularly distributed samples. Second, based on the Barnhill's modification of Shepard's method, a new modified Shepard method is developed to interpolate the potential values on the heart surface. Results are compared to Barnhill's using his test functions and the new method shows considerable improvement. In addition to these standard test functions, a 'surface sigmoid' function is used to create sharper transitions. Comparison with the ordinary Shepard's method again shows reasonable accuracy and considerable improvement. The method was also used on measured data.