Impedance-based cardiac therapy planning method with a remote surgical navigation system

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.