Interference-fit shroud-based cardiac electrodes

• US 7,881,765 B2
• Filed: 04/28/2006
• Issued: 02/01/2011
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Strom, James, Fischer, Steven J., Zart, Bryan J., Nicholson, John E., Mertz, John C., Fletcher, Michael D.
• Primary Examiner(s): Bockelman; Mark W
• Assistant Examiner(s): Dinga; Roland
• Application Number:
  US11/380,773
• Publication Number:
  US 20070255156A1
• Time in Patent Office: 1,740 Days
• Field of Search: 600/372, 600/373, 600/374, 600/377, 607/9, 607/36, 607/116, 607/119
• US Class Current: 600/377
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/29 for permanent or long-term implantation
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61N 1/0504 Subcutaneous electrodes
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: A61N 1/37514 Brain implants
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators

Abstract

Apparatus and method according to the disclosure relate to minimizing gaps between a substantially planar cardiac-sensing electrode and a shroud member utilizing a so-called interference-fit. For example, a relatively recessed area or aperture formed in an exemplary resin-based shroud member has slightly reduced dimensions relative to the electrode and requires compression forces during assembly (e.g., manually or in an automated process including a press, a tool or other means). The interference-fit promotes a very tight fit (or seal) between the metallic electrode and the resin-based shroud member and, importantly, minimizes gaps. Additionally, discrete interference structures promote fluid tight seals between the electrode and a recess or aperture adapted to receive the electrode.

Claims

1. A subcutaneous cardiac activity sensing shroud, comprising:

a shroud member for location adjacent at least a part of the peripheral portion of a housing for an implantable medical device (IMD), said shroud member including one of a recessed region and an aperture; and

a substantially planar, plate-type electrode having a periphery that mechanically sealingly interlocks to one of the recessed region and the aperture,

wherein at least a portion of an interior periphery of said recessed region or said aperture includes an interference structure configured to sealingly receive the electrode when said electrode is disposed therein.

2. A shroud according to claim 1, wherein said interference structure comprises a resilient material.

3. A shroud according to claim 1, further comprising a compressible member disposed intermediate the electrode and the shroud where the electrode and the shroud are abutting each other.

4. A shroud according to claim 3, wherein the compressible member comprises a resin-based member.

5. A shroud according to claim 3, wherein the compressible member comprises a biocompatible gasket and further comprising a medical grade adhesive coupled between one of:

the biocompatible gasket and the electrode and the biocompatible gasket and the shroud.

6. A shroud according to claim 3, wherein the compressible member comprises a member having a C-shaped cross-sectional configuration.

7. A shroud according to claim 3, wherein the compressible member comprises a member having opposing C-shaped cross sectional configuration.

8. A shroud according to claim 1, further comprising an elongated conductor coupled to one of a major surface of the electrode and a peripheral portion of the major electrode.

9. A shroud according to claim 8, wherein the elongated conductor comprises an integrally formed structure with the electrode.

10. A shroud according to claim 1, wherein the electrode comprises one of a titanium material and a platinum material.

11. A shroud according to claim 1, further comprising medical grade adhesive disposed around between at least a part of the periphery of the electrode and the periphery of the recessed region or the aperture.

12. A shroud according to claim 1, wherein the electrode further includes a coating on at least a major surface thereof.

13. A shroud according to claim 12, wherein the coating comprises one of a nitride coating, a carbon black coating, a time-release coating.

14. A subcutaneous cardiac activity sensing shroud, comprising:

a shroud member for location adjacent at least a part of the peripheral portion of a housing for an implantable medical device (IMD), said shroud member including one of a recessed region and an aperture;

a substantially planar, plate-type electrode having a periphery that mechanically sealingly interlocks to one of the recessed region and the aperture,

wherein at least a portion of an interior periphery of said recessed region or said aperture includes an interference structure configured to sealingly receive the electrode when said electrode is disposed therein;

an electrode aperture formed in a major surface of the electrode; and

an additional interference structure, wherein the additional interference structure extends from a major surface of the recessed region and sealingly engages the electrode aperture.

15. A shroud according to claim 14, wherein the additional interference structure includes a continuous interference structure around the periphery thereof configured to sealingly engage the electrode aperture.

16. A method of fabricating a cardiac sensing shroud assembly, comprising:

providing a resilient shroud member adapted to be mounted around at least a part of the peripheral portion of a housing for an implantable medical device (IMD);

forming one of a recessed region and an aperture in a peripheral portion of the shroud member; and

compressing a substantially planar, plate-type electrode into positive engagement with an interference structure, wherein the interference structure promotes a mutually interlocking sealing relationship between the electrode and one of the recessed region and the aperture.

17. A method according to claim 16, wherein the interference structure comprises a gasket having a C-shaped cross section.

18. A method according to claim 16, further comprising:

coupling the shroud member around at least a part of the peripheral portion of the IMD, and wherein the IMD comprises one of;

an implantable cardiac pacemaker, an implantable cardioverter-defibrillator, an implantable fluid delivery device, an implantable neurostimulator, an implantable gastric simulator.