Patent ID: 6966908

Claim:
A tissue ablation system for treating atrial arrhythmia by ablating a circumferential region of tissue at a location where a pulmonary vein extends from an atrium, comprising: a delivery member with a proximal end portion and a distal end portion with a longitudinal axis and a radial axis; a circumferential ablation member cooperating with the delivery member, the delivery member being adapted to at least in-part deliver the circumferential ablation member to the location, the circumferential ablation member having, a circumferential support member that is adjustable between a first position which is adapted to be delivered through a delivery sheath into the atrium and a second position having a substantially circumferentially looped shape, the circumferential support member comprising an elongate body which in the first position has a substantially straight shape relative to the longitudinal axis with a proximal end secured to the distal end portion, a distal end extending away from the distal end portion substantially along the longitudinal axis, and an intermediate region extending between the proximal and distal ends, wherein in the second position the elongate body is adjusted to the substantially circumferentially looped shape, an ablation element located substantially along the circumferential support member and that is adapted to ablatively couple to a circumferential area adjacent to the support member in the second position, and a positioning means coupled to the circumferential support member to adjust the circumferential support member between the first and second positions when the circumferential support member is substantially unconfined within the atrium, wherein the ablation element and the circumferential support member are configured such that the circumferential area coincides with the circumferential region of tissue when the circumferential support member is adjusted to the second position at the location.