Patent ID: 8827994

Claim:
An apparatus, comprising a catheter defining a first lumen and a second lumen; a conductive element disposed along the catheter; a first expandable member having an interior in fluid communication with the first lumen of the catheter and comprising a plurality of conductive portions formed at least in part of a conductive material and conductively coupled to the at least one conductive element; and a second expandable member having an interior in fluid communication with the second lumen of the catheter and comprising at least one conductive portion formed of a conductive material and conductively coupled to the at least one conductive element, the conductive portion of the second expandable member being disposed within the interior of the first expandable member, wherein (a) the first expandable member and the second expandable member each have a collapsed configuration and an expanded configuration, and (b) at least one conductive portion of the second expandable member defines a first electrical pole, and two conductive portions of the first expandable member define second and third electrical poles, such that, when a potential is applied between the first electrical pole and the second and third electrical poles, a first RF field is formed between the first and second electrical pole and a second RF field is formed between the first and third RF pole.