Patent ID: 7340307

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 having a proximal end portion and a distal end portion with a longitudinal axis and a radial axis; a cantilevered housing having a first end, a second end, and a distal wall, that is located at least in part along the distal end portion, and that is mechanically adjustable between a first condition and a second condition, wherein in the first condition the distal wall is substantially radially collapsed such that the housing is adapted to be delivered through a delivery sheath into the atrium, and wherein in the second condition the second end and the distal wall are radially extended at least in part from the longitudinal axis, the distal wall having a distal orientation and a distal facing surface substantially perpendicular to the longitudinal axis located along a circumferential region that surrounds the longitudinal axis; a mechanical positioning assembly coupled to the first end of the housing to mechanically adjust the housing between the first and second conditions; and an ablation element cooperating with the housing and which is adapted to ablatively couple to a circumferential area normal to the distal facing surface along the circumferential region when the housing is in the second position, wherein the ablation element and distal facing surface are configured such that the circumferential area coincides with the circumferential region of tissue when the housing is adjusted to the second condition at the location.