| 摘要 |
An improved electrode tip (16) is disclosed which utilizes a plurality of carbon fibers (30) to form a portion of the electrode tip. These carbon fibers (30) are utilized to sense electrical activity within the user's heart, and in at least one embodiment to provide stimulation pulses to the heart. The fibers are chosen to have a cross-sectional diameter of less than 15 micrometers. These fibers form a limited porosity surface and allow a certain amount of tissue ingrowth, thereby providing passive electrode fixation. A body portion (24) of the electrode tip (16) forms an annular lip (32) which provides a surface for conducting stimulation pulses to the heart. Thus, a relatively small area is provided by the annular lip (32) for conduction of the stimulation pulses, thereby providing a high current density and less resistance. A larger surface area and a higher resistance is provided by the carbon fiber ends (44) for sensing electrical activity in the heart. In a still further embodiment of the invention, a porous retaining mesh (68) is located over a carbon fiber tip ( 66) for providing a more positive fixation by heart tissue ingrowth. The carbon fibers 30 are compressed to form a fiber compress in which the fibers form at least 85 percent of the compress volume.
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