| 摘要 |
An implantable lead (10) for establishing electrical contact between a medical device and body tissue, in which an active fixation mechanism (18) secures the lead (10) in place while allowing a distal electrode (14) on the lead to mechanically "float" with respect to the body tissue. In one embodiment, the active fixation mechanism (18) comprises a curved hook disposed on the lead (10) at a point spaced proximally back from the distal end (14) of the lead (10). The curved hook (18) defines a helix around at least a portion of the lead's circumference. A hollow introducer needle is slidably disposed on the lead (10). The hollow needle is provided with a longitudinal slit in a distal section of its length, such that the distal section of the needle can be advanced over the distal end (14) the lead (10), past the fixation hook, which is received in the longitudinal slit. With the needle slid over the distal end (14) of the lead (10), the needle is stabbed angentially into an implant site, bringing the fixation hook (18) proximal to the surface of the body tissue. Then, the needle is twisted (bringing about a twisting of the lead (10)), causing the curved fixation hook (18) to pierce and engage the body tissue, securing the lead (10) in place. Then the needle is withdrawn from the body tissue and removed from the lead (10). In an alternative embodiment, the lead (10) can be placed by an endocardial approach using a flexible cannula with a longitudinally slotted tip.
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