| 摘要 |
A medical lead having a diameter of no greater than 3 French and employing an insulation material that is substantially stiffer than would normally be employed in the context of a permanently implantable cardiac pacing lead is disclosed. A material having a Young's modulus of at least 25,000 pounds per square inch such as Pellethane 2363-75D, or an even stiffer polymer, is used to provide a lead body that does not exhibit a whip-like effect in response to such movement as would occur during a heart beat. In order to prevent the increased stiffness of the lead body from increasing the possibility that the distal lead tip will perforate the heart tissue, the lead is provided with a distal surface that is not reduced in size. This surface reduces the pressure exerted by the distal lead tip upon body tissue to no greater than 3.6 pounds per square inch. The distal tip may carry an electrode of the same or substantially smaller surface area, allowing the lead to retain desirable electrical characteristics for sensing of cardiac depolarizations and delivery of cardiac pacing pulses.
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