Bipolar belt systems and methods

A radiofrequency ablation system for treating tissue around a group of pulmonary veins, the system comprising:

• an ablation apparatus with a plurality of ablation elements carried by a flexible tube structure where ends of the flexible tube are configured to extend away from the plurality of ablation elements such that the plurality of ablation elements can be positioned around the group of the pulmonary veins and the ends of the flexible tube are configured to receive a pulling force to secure the plurality of ablation elements against the tissue being treated;
• a radiofrequency generator capable of delivering a plurality of differing radiofrequency power signals to the plurality of ablation elements of the ablation apparatus such that a first set of the plurality of ablation elements are configured to function as delivery electrodes and a second set of the plurality of ablation elements are configured to function as return electrodes, wherein the plurality of differing radiofrequency power signals permits a plurality of conductive paths between the plurality of ablation elements, wherein the plurality of conductive paths each comprise a pair of a delivery electrode and a return electrode;
• wherein the plurality of conductive paths are configured to be varied between different pairs of delivery electrodes and return electrodes;
• wires transmitting the plurality of differing radiofrequency power signals from the radiofrequency generator to the plurality of ablation elements;
• and
• a control mechanism to enable temperature-based power control to each of the plurality of powered ablation elements.