US Patent 7530980 Bipolar transmural ablation method and apparatus

A method and apparatus for creating transmural ablations in heart tissue, for example, may include two or more electrodes adapted to be connected to opposite poles of a bipolar RF generator so as to energize the electrodes to ablate cardiac tissue between the electrodes. A first electrode may be inserted into cardiac tissue at a first location and a second electrode may be inserted into cardiac tissue at a second location which is spaced from the first location. At least one of the electrodes may be adapted to provide a sufficiently low current density in the vicinity of the electrode to avoid substantial tissue desiccation when energized. Alternatively, the apparatus may include at least one bipolar ablation electrode which comprises an elongated conductive member of spiral shape having a pitch sufficiently small to provide sufficient surface area to avoid substantial desiccation of tissue when energized by a bipolar RF generator.