Inverse Localization of Intraventricular Pacing Sites by Equivalent Dipole Source

Localization of seven intraventricular pacing sites in the left ventricle was performed using a single dipole as equivalent heart generator. The used data were provided by Karlsruhe Institute of Technology in EDGAR database. Body surface potential maps were measured in 63 precordial leads during intraventricular pacing with recorded position of the stimulating catheter. The inverse solution was computed for instantaneous and integral maps from the initial 30 ms time interval of ventricular activation. The role of the relative residual error between the input map and the map computed from the resulting dipole was studied with respect to the accuracy of the inverse solution. The localization error of the obtained results for the initial 30 ms was dependent on the position of the pacing site and varied from 20-30 mm for anterior and lateral sites to 45-55 mm for inferior sites. The results were improved considerably when the considered time interval was prolonged and the inverse solution was computed for the time instant when the residual error reached its minimum. The proper time instant for computation of the input data for localization of pacing sites should be chosen individually for each ECG signal.