Continuous conductive materials for electromagnetic shielding

• US 10,537,730 B2
• Filed: 02/14/2007
• Issued: 01/21/2020
• Est. Priority Date: 02/14/2007
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Li, Bernard, Cai, Chad, Chen, Xingfu
• Primary Examiner(s): Abreu, Michael J D
• Application Number:
  US11/674,995
• Publication Number:
  US 20080195186A1
• Time in Patent Office: 4,724 Days
• Field of Search: 607 2, 607 9, 607 36, 607115, 607116
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents

Abstract

A medical electrical lead having a conductor assembly covered by an insulating layer, and a shield covering positioned adjacent or proximate to at least a portion of the insulating layer in order to shield the conductor assembly from one or more electromagnetic fields. The shield covering is formed of a material that is electrically conductive, where the material is in a wrapped or woven form. The material is selected so as to have an effective combination of small size and high conductive surface area, e.g., as opposed to metal wire or coatings thinner than metal wire. As such, the shield covering exhibits sufficient conductivity in the presence of one or more high frequency electromagnetic fields so that interference to the operation of the conductor assembly is minimized. The material can have a coating formed of one or more metals. The material can include carbon. In turn, the carbon can be formed of one or more of carbon fiber, carbon nanofiber, and single or multi-walled carbon nanotube.

Claims

1. An apparatus for alleviating the adverse effects of various health ailments of a patient comprising:

a medical device; and

an electrical lead connected to the medical device at a proximal end of the lead and having at least a distal end, the distal end of the electrical lead having one or more electrodes or electrical contacts for sensing and/or therapy delivery, the electrical lead comprising a conductor assembly having one or more conductors covered by an insulating layer and the electrical lead further comprising a shield covering adjacent in a radial direction or proximate in the radial direction to at least a portion of the insulating layer to shield the conductors from one or more electromagnetic fields, the shield covering comprising carbon or coated carbon fibers, the carbon or coated carbon fibers forming a material that is in a wrapped or woven form so as to form a layer of the shield covering having multiple turns of the material where each turn of the material forming the layer wraps completely around the insulating layer and contacts another turn of the material that is adjacent in an axial direction of the lead and where the contact between adjacent turns of the material occurs over the entire circumference of each turn, the carbon or coated carbon fibers having an effective combination of small size and high surface area for sufficient conductivity in presence of one or more high frequency electromagnetic fields so that interference to the operation of the one or more conductors is minimized.

2. The apparatus of claim 1, wherein the carbon is formed of one or more of carbon fiber, carbon nanofiber, and carbon nanotube having one or more of single and multiple walls.

3. The apparatus of claim 1, wherein the carbon has one or more conductive members each having an outer diameter that is no greater than about 20 μ

m.

4. The apparatus of claim 1, wherein the carbon has a higher skin depth than metal.

5. The apparatus of claim 1, wherein the coated carbon fibers have a coating formed of one or more metals, the coating formed or attached around the carbon, the coating and the shield covering providing an enhanced shielding effect for the one or more conductors.

6. The apparatus of claim 1, wherein the medical device is an implantable medical device, the device and the electrical lead being implanted within the patient.

7. The apparatus of claim 1, wherein the electrical lead further includes a lead extension electrically connecting the lead to the medical device, the shield covering positioned adjacent or proximate to at least a portion of the lead extension.

8. The apparatus of claim 1, wherein the multiple turns do not overlap.

9. The apparatus of claim 1, wherein the multiple turns do overlap.

10. An apparatus for alleviating the adverse effects of various health ailments of a patient comprising:

a medical device; and

an electrical lead connected to the medical device at a proximal end of the lead and having at least a distal end, the distal end of the electrical lead having one or more electrodes or electrical contacts for sensing and/or therapy delivery, the electrical lead comprising;

a conductor assembly having one or more conductors covered by an insulating layer,

a shield covering adjacent in a radial direction or proximate in the radial direction to at least a portion of the insulating layer to shield the conductors from one or more electromagnetic fields, the shield covering formed of carbon, the carbon forming a material that is in a wrapped or woven form so as to form a layer of the shield covering having multiple turns of the material where each turn of the material forming the layer wraps completely around the insulating layer and contacts another turn of the material that is adjacent in an axial direction of the lead and where the contact between adjacent turns of the material occurs over the entire circumference of each turn, and

a conductive layer immediately adjacent the shield covering that encircles the conductor assembly.

11. The apparatus of claim 10, wherein the conductive layer is a metal coating exterior to the shield covering.

12. The apparatus of claim 10, further comprising a metal braid or sheath interior to the shield covering.

13. An apparatus for alleviating the adverse effects of various health ailments of a patient comprising:

a medical device; and

an electrical lead connected to the medical device at a proximal end of the lead and having at least a distal end, the distal end of the electrical lead having one or more electrodes or electrical contacts for sensing and/or therapy delivery, the electrical lead comprising a conductor assembly having one or more conductors covered by an insulating layer and a shield covering adjacent in a radial direction or proximate in the radial direction to at least a portion of the insulating layer to shield the conductors from one or more electromagnetic fields, the shield covering formed of carbon that encircles the conductor assembly, the carbon forming a material that is in a wrapped or woven form so as to form a layer of the shield covering having multiple turns of the material where each turn of the material forming the layer wraps completely around the insulating layer and contacts another turn of the material that is adjacent in an axial direction of the lead and where the contact between adjacent turns of the material occurs over the entire circumference of each turn, the carbon having an effective combination of small size and high surface area for sufficient conductivity in presence of one or more high frequency electromagnetic fields so that interference to the operation of the one or more conductors is minimized.