ACTIVE IMPLANTABLE MEDICAL SYSTEM HAVING EMI SHIELDED LEAD

• US 20100280584A1
• Filed: 05/26/2010
• Published: 11/04/2010
• Est. Priority Date: 04/13/2001
• Status: Active Grant

• Current Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Original Assignee: Greatbatch Limited (Greatbatch Incorporated)
• Inventors: Nesselbeck, Neal, Dabney, Warren S., Stevenson, Robert A., Spaulding, Joseph, Lardo, Albert C., Moschiano, Holly Noelle, Johnson, Robert Shawn, Halperin, Henry R., Kondabatni, Kishore Kumar
• Granted Patent: US 8,849,403 B2
• Time in Patent Office: Days
• US Class Current: 607/116
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/415 the glands, e.g. tonsils, adenoids or thymus
• CPC Class Codes: A61B 5/418 lymph vessels, ducts or nodes
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• 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
• CPC Class Codes: G01R 33/285 Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR

Abstract

A lead extending exteriorly from an active implantable medical device (AIMD) is at least partially ensheathed within an electromagnetic interference (EMI) shield. The AIMD has a conductive equipotential surface to which the EMI shield may be conductively coupled. An impeding circuit may be provided for raising the high frequency impedance of the lead. An energy diversion circuit may also be provided for conductively coupling the lead to the EMI shield.

Claims

1. An implantable medical system, comprising:

an active implantable medical device (AIMD) having a conductive equipotential surface;

at least one lead having a length exteriorly extending from a proximal end at or adjacent to the AIMD to a biological sensing or stimulating electrode at a distal end; and

an electromagnetic interference (EMI) shield surrounding the at least one lead along at least a portion of the length thereof, the EMI shield being conductively coupled to the AIMD equipotential surface.

2. The system of claim 1, wherein the AIMD equipotential surface comprises a biocompatible housing for the AIMD.

3. The system of claim 1, including an insulator surrounding the EMI shield along its length.

4. The system of claim 1, 2 or 3, wherein the EMI shield comprises a plurality of EMI shields disposed along the length of the at least one lead.

5. The system of claim 4, wherein an adjacent pair of the plurality of EMI shields are spread apart from one another.

6. The system of claim 4, wherein the plurality of EMI shields are conductively coupled to one another.

7. The system of claim 1, 2 or 3, wherein the at least one lead comprises a plurality of leads, and wherein the EMI shield comprises a corresponding plurality of EMI shields.

8. The system of claim 1, including a non-conductive insulator disposed between the lead and the EMI shield.

9. The system of claim 1, wherein the EMI shield comprises a conductive heat-shrink tubing.

10. The system of claim 1, wherein the EMI shield comprises a conductive foil, wire, braid, mesh, circuit trace, or solid tubular material, or a deposited thin film of conductive material.

11. The system of claim 10, wherein the EMI shield comprises a conductive polymer, a conductive epoxy, carbon nano-fibers, nano-meshes or nano-threads.

12. The system of claim 1, wherein the EMI shield includes one or more stress relief scores.

13. The system of claim 1, wherein the EMI shield is radially spaced from the at least one lead.

14. The system of claim 1, wherein the EMI shield comprises MP35N, iridium, platinum, titanium, chromium, Wolfram, tungsten, gold or copper.

15. The system of claim 1, including a flex cable embodying the at least one lead and the EMI shield.

16. The system of claim 2, including a hermetic feedthrough terminal associated with the AIMD housing, wherein the at least one lead extends through the hermetic feedthrough terminal.

17. The system of claim 1, 2 or 3, including an energy diversion circuit conductively coupling the at least one lead to the EMI shield.

18. The system of claim 17, wherein the energy diversion circuit comprises a low pass filter.

19. The system of claim 18, wherein the low pass filter comprises a capacitor, an inductor, a Pi filter, a T filter, an LL filter, or an “

n”

element filter.

20. The system of claim 17, wherein the energy diversion circuit comprises at least one series resonant L-C trap filter.

21. The system of claim 1, 2 or 3, including an impeding circuit for raising the high frequency impedance of the at least one lead.

22. The system of claim 21, wherein the impeding circuit comprises an inductor.

23. The system of claim 21, wherein the impeding circuit comprises a bandstop filter.

24. The system of claim 21, including an energy diversion circuit conductively coupling the at least one lead to the EMI shield.

25. The system of claim 24, wherein the energy diversion circuit comprises a low pass filter.

26. The system of claim 25, wherein the low pass filter comprises a capacitor, an inductor, a Pi filter, a T filter an LL filter, or an “

n”

element filter.

27. The system of claim 25, wherein the energy diversion circuit comprises at least one series resonant L-C trap filter.

28. The system of claim 24, wherein the energy diversion circuit comprises a high pass filter.

29. The system of claim 28, wherein the high pass filter prevents low frequency gradient field-induced energy in the implanted lead from passing through the diversion circuit to the energy dissipating surface.

30. The system of claim 28, wherein the high pass filter comprises a capacitor.

31. The system of claim 30, wherein the high pass filter comprises a resistor in series with a capacitor.

32. The system of claim 28, wherein the high pass filter comprises an L-C trap filter.

33. An implantable medical system, comprising:

an active implantable medical device (AIMD);

at least one lead having a length exteriorly extending from a proximal end at or adjacent to the AIMD, to a biological sensing or stimulating electrode at a distal end; and

an electromagnetic interference (EMI) shield surrounding the at least one lead along at least a portion of the length thereof, the EMI shield including an electrically conductive exterior surface suitable for long-term exposure to body tissues/fluids.

34. The system of claim 33, including a non-conductive insulator disposed between the lead and the EMI shield.

35. The system of claim 33, wherein the EMI shield comprises a conductive heat-shrink tubing.

36. The system of claim 33, wherein the EMI shield comprises a conductive foil, wire, braid, mesh, circuit trace, or solid tubular material.

37. The system of claim 33, wherein the EMI shield comprises a conductive polymer, a conductive epoxy, carbon nano-fibers, nano-meshes or nano-threads.

38. The system of claim 33, wherein the EMI shield includes one or more stress relief scores.

39. The system of claim 33, wherein the EMI shield is radially spaced from the at least one lead.

40. The system of claim 33, wherein the EMI shield comprises MP35N, iridium, platinum, titanium, chromium, Wolfram, tungsten, gold or copper.

41. The system of claim 33, including a flex cable embodying the at least one lead and the EMI shield.

42. The system of claim 33, wherein the AIMD has a conductive equipotential surface, and wherein the EMI shield is conductively coupled to the AIMD equipotential surface.

43. The system of claim 42, wherein the AIMD equipotential surface comprises a biocompatible housing for the AIMD.

44. The system of claim 33, 42 or 43, wherein the EMI shield comprises a plurality of EMI shields disposed along the length of the at least one lead.

45. The system of claim 44, wherein an adjacent pair of the plurality of EMI shields are spread apart from one another.

46. The system of claim 44, wherein the plurality of EMI shields are conductively coupled to one another.

47. The system of claim 33, 42 or 43, wherein the at least one lead comprises a plurality of leads, and wherein the EMI shield comprises a corresponding plurality of EMI shields.

48. The system of claim 43, including a hermetic feedthrough terminal associated with the AIMD housing, wherein the at least one lead extends through the hermetic feedthrough terminal.

49. The system of claim 33, 42 or 43, including an energy diversion circuit conductively coupling the at least one lead to the EMI shield.

50. The system of claim 49, wherein the energy diversion circuit comprises a low pass filter.

51. The system of claim 50, wherein the low pass filter comprises a capacitor, an inductor, a Pi filter, a T filter, an LL filter, or an “

n”

element filter.

52. The system of claim 49, wherein the energy diversion circuit comprises at least one series resonant L-C trap filter.

53. The system of claim 49, wherein the energy diversion circuit comprises a high pass filter.

54. The system of claim 53, wherein the high pass filter prevents low frequency gradient field-induced energy in the implanted lead from passing through the diversion circuit to the energy dissipating surface.

55. The system of claim 53, wherein the high pass filter comprises a capacitor.

56. The system of claim 53, wherein the high pass filter comprises an L-C trap filter.

57. The system of claim 33, 42 or 43, including an impeding circuit for raising the high frequency impedance of the at least one lead.

58. The system of claim 57, wherein the impeding circuit comprises an inductor.

59. The system of claim 57, wherein the impeding circuit comprises a bandstop filter.