| 摘要 |
<p>A system for cryoablating tissue at a target site in a patient includes a cryotip (24) attached to the distal end of a catheter tube (12). The cryotip is made of a conductive polymer material that is heat set into a spiral configuration. Inside the cryotip is a configuration lumen (52). The cryotip assumes a straight configuration when a straightening member (38) is positioned in the configuration lumen, and it assumes the spiral configuration when the straightening member is absent from the configuration lumen. The cryotip in the straight configuration is guided through the vasculature of a patient to the target site. At the target site, the straightening member is removed to configure the cryotip info the spiral configuration to contact the cryotip with circumferential tissue around the target site. A refrigerant fluid is then introduced into the expansion chamber of the cryotip to cool the tip to cryoablate the circumferential tissue. <IMAGE></p> |
