Cardiac catheterization is carried out by clothing a subject in a torso vesthaving a plurality ofsensing electrodes, magnetic location sensors, active current location sensorsand patches for establishinggalvanic contact with the skin. A multi-electrode probe is inserted into acardiac chamber suchthat a plurality of intracardiac electrodes are disposed at respectivelocations in the heart. Respectivelocations are determined using the active current location sensors, Electricalcalibration signals areemitted from the intracardiac electrodes, and received in the sensingelectrodes of the torso vest. Relationshipsbetween the emitted calibration signals and the received calibration signalsin the intracardiacelectrodes are established to map a correspondence between the receivedcalibration signals andthe respective locations.
