FEASIBILITY OF ESTIMATING ENDOCARDIAL POTENTIALS FROM CAVITY POTENTIALS.
The feasibility of estimating endocardial potentials from cavity potentials is assessed quantitatively. The model considered is an electrically homogeneous cavity region bounded externally by the endocardial surface and by the surface of the intracavity probe from the inside. Assuming that the primary and secondary sources are external to the region, the use of Green's theorem yields a transfer coefficient matrix relating probe potentials and endocardial potentials. Once the covariance of the measured voltages and the covariance of the signal are specified, the expected error can be computed prior to finding or using the inverse of the transfer coefficient matrix. Simulations were performed for an idealized spherical endocardium with 89 electrodes positioned as in previously conducted animal experiments. The results suggest that 89 endocardial potentials can be estimated more accurately from 58 cavity measurements than 89 epicardial potentials can be estimated from 160 torso potential measurements.
