INTERFERENCE-FIT SHROUD-BASED CARDIAC ELECTRODES

• US 20070255156A1
• Filed: 04/28/2006
• Published: 11/01/2007
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Strom, James, Nicholson, John, Mertz, John, Zart, Bryan, Fischer, Steven, Fletcher, Michael
• Granted Patent: US 7,881,765 B2
• Time in Patent Office: Days
• US Class Current: 600/527
• 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 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, wherein the substantially planar, plate-type electrode mechanically sealingly interlocks to its periphery to one of the recessed region and the aperture,

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

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

3. A shroud according to claim 2, wherein said interference structure comprises one of:

a protruding lip member, a pair of spaced apart coaxial protruding rings,

4. A shroud according to claim 3, wherein one of the pair of spaced apart coaxial protruding rings includes a first inner radius dimension and the first inner radius dimension differs from a second inner radius dimension of the second of the coaxial protruding rings.

5. 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.

6. A shroud according to claim 5, wherein the compressible member comprises a resin-based member.

7. A shroud according to claim 5, 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.

8. A shroud according to claim 5, wherein the compressible member comprises a member having a C-shaped cross-sectional configuration.

9. A shroud according to claim 5, wherein the compressible member comprises a member having opposing C-shaped cross sectional configuration.

10. A shroud according to claim 1, further comprising:

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.

11. A shroud according to claim 6, wherein the additional interference structure includes a continuous interference structure around the periphery thereof configured to sealingly engage the electrode aperture.

12. 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.

13. A shroud according to claim 12, wherein the elongated conductor comprises an integrally formed structure with the electrode.

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

15. 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.

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

17. A shroud according to claim 1, wherein the coating comprises one of a nitride coating, a carbon black coating, a time-release coating.

18. 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.

19. A method according to claim 18, wherein the interference structure comprises a gasket having a C-shaped cross section.

20. A method according to claim 18, 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.