This invention is a circumferential
ablation device
assembly which is adapted to forming a circumferential conduction block in a
pulmonary vein. The
assembly includes a circumferential
ablation element which is adapted to ablate a circumferential region of tissue along a
pulmonary vein wall which circumscribes the
pulmonary vein lumen, thereby transecting the electrical
conductivity of the pulmonary
vein against conduction along its longitudinal axis and into the
left atrium. The circumferential
ablation element includes an expandable member with a working length that is adjustable from a radially collapsed position to a radially expanded position. An equatorial band circumscribes the outer surface of the working length and is adapted to ablate tissue adjacent thereto when actuated by an ablation
actuator. The equatorial band has a length relative to the longitudinal axis of the expandable member that is narrow relative to the working length, and is also substantially shorter than its circumference when the working length is in the radially expanded position. A pattern of insulators may be included over an ablation element which otherwise spans the working length in order to form the equatorial band described. The expandable member is also adapted to conform to the pulmonary
vein in the region of its
ostium, such as by providing a great deal of radial compliance or by providing a taper along the working length which has a distally reducing outer
diameter. A linear ablation element is provided adjacent to the circumferential ablation element in a combination
assembly which is adapted for use in a less-invasive “maze”-type procedure in the region of the pulmonary
vein ostia in the left
ventricle.