Patent ID: 8273081

Claim:
A method of defining ablation lines in the left atrium of the heart, comprising: i) performing impedance mapping of the left atrium and a pair of pulmonary veins; ii) for each pulmonary vein, defining an impedance threshold value corresponding to the pulmonary vein ostium; iii) defining iso-impedance contours for each of the veins based on corresponding impedance threshold ii) and impedance mapping i); iv) determining whether the two iso-impedance contours iii) are a) crossing; b) tangent; or c) neither; v) increasing or decreasing the two respective impedance contour values by a predetermined amount if the contours are crossing, or not, respectively, and defining corresponding iso-impedance contours; vi) iterating over steps iv) and v) until the two contours are tangent, and defining an associated single iso-impedance contour; and vii) retaining the corresponding iso-impedance contour as a pulmonary vein pair ablation line.