Effect of Surface Electrode Number on Estimates of Cardiac Dipole Moment

This study reports on the errors in the calculation of a heart dipole introduced by deleting individual electrode contributions to a surface potential map. The potential at 150 points on each of 6 normal children was available at several instants of the QRS cycle. Although it was impossible to test all possible sets of deleted points, or all possible methods of compensatory weighting of the residual points, the results indicate that a number of electrodes at least as great as 100 is required to produce consistent relative errors of less than 15 percent, if surface potential integration is employed in determining the heart's total dipole moment.