| 摘要 |
<p>A circumferential ablation device assembly includes a circumferential ablation member with an ablation element that is adapted to ablate a circumferential region of tissue in the region of a pulmonary vein ostium. The ablation element couples to a middle portion of the circumferential ablation member and which is bordered on either side by two end portions. The end portions are adapted to shield and thereby isolate ablative energy from the ablation element to the circumferential region of tissue adjacent the middle region. The ablation element is coupled to an expandable member with a working length that is adjustable to a radially expanded position which engages the circumferential region of tissue, and may be coupled only to a narrow circumferential band that circumscribes the outer surface of the working length to form the middle region adapted to ablate tissue adjacent thereto. The ablation element may couple to the entire working length of the expandable member, and insulators may be provided over both end portions to leave the circumferential band as the only ablative middle region. The expandable member conforms to the pulmonary vein ostium, such as by providing a great deal of radial compliance or by providing a taper along the working length with a distally reducing outer diameter. The ablation element may be any energy sink adapted to couple to and ablate the circumferential region, although in one mode an ultrasound transducer is ultrasonically coupled to the circumferential band to either heat the band or pass through the band in order to ablate the circumferential region of tissue. A linear ablation element is provided adjacent to the 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 atrium.</p> |
