| 摘要 |
A lead with an increased impedance for an active implantable medical device, in particular for a pacemaker. The lead comprises a cylindrical body (14) presenting at its distal end a contact surface (30) for making contact with the endocardium, which is electrically insulated, and a stimulation electrode (16), which is electrically conducting and which is connected to a conductor of the lead. The electrode (16) has at least one active element (22), for example, a plurality of protuberances (22), each one presenting at least an exposed extremity tip (26) having a hemispherical area, making a ledge compared to the contact surface (i.e., protruding) therefrom. The active element presents on at least a part of its exposed extremity to be placed in contact with the endocardium a radius of curvature less than 0.5 mm, more preferably less than or equal to 0.3 mm. With a microporous vitreous carbon as the material of the protuberances, one can at least increase the contact impedance of the lead at the heart/electrode interface to 800 Ohm, preferably up to approximately 1000 Ohm. An annular flat form or disc-shaped active element also can be used as an alternative to the protuberance(s).
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