Multi-electrode probe for thermal ablation

Abstract

A multi-electrode probe for use with a catheter in an electrophysiological procedure to map and to ablate any of several tissue sites without repositioning the probe includes at least a plurality of electrodes, such as a tip and metallic rings, less than all of the electrodes has a first work function and are selectively energized by a source of RF energy. The RF energy return path is through a further electrode(s) of a metallic material having a second work function and disposed at a tissue location removed from the ablation site. After the sites have been mapped and one or more sites are selected for ablation, the selected site(s) is ablated prior to any repositioning of the probe. Regulation of the temperature at the ablation site(s) is achieved by sensing the temperature dependent current of a galvanic cell created by the tissue between the energized tip/ring and the further electrode due to their different work functions.