Electrode assembly

1. An electrode assembly for an active implantable medical device comprising:

an elongated, biocompatible, electrically non-conductive body having a first portion and a second portion;

one or more biocompatible, electrically conductive filaments inside the elongated non-conductive body between the first portion and the second portion, the one or more conductive filaments being electrically insulated;

one or more fluid passages along the elongated electrically non-conductive body between the first portion and second portion, the one or more fluid passages allowing a surrounding fluid of a patient to be in electrical contact with the one or more conductive filaments; and

one or more channels along the elongated electrically non-conductive body, the one or more channels providing the one or more fluid passages from an outer surface of the electrically non-conductive body to the one or more conductive filaments.

2. The electrode assembly according to claim 1 comprising:

a plurality of apertures along the elongated electrically non-conductive body, the plurality of apertures providing the fluid passages from the outer surface of the electrically non-conductive body to the one or more conductive filaments.

3. The electrode assembly according to claim 1 comprising:

one or more conductive filament lumens to receive respective conductive filaments passing through the elongated electrically non-conductive body, the one or more conductive filament lumens having a diameter greater than the respective conductive filament to provide at least part of the one or more fluid passages.

4. The electrode assembly according to claim 1 comprising:

one or more plugs in the one or more fluid passages, the plugs comprising a biocompatible biodegradable material for biodegrading in a body of the patient after implantation.

5. The electrode assembly according to claim 1 further comprising:

a biocompatible biodegradable sheath to surround the elongated electrically non-conductive body, the biodegradable sheath biodegrading in a body of the patient after implantation.

6. The electrode assembly according to claim 1 further comprising a central lumen in the elongated electrically non-conductive body to receive a stylet.

7. The electrode assembly according to claim 1 , wherein the biocompatible, elongated electrically non-conductive body comprises:

an outer wall; and

a cavity within the outer wall, the cavity containing the one or more conductive filaments disposed within a biocompatible biodegradable material,

the biodegradable material biodegrading in a body of a patient after implantation.

8. The electrode assembly according to claim 7 , further comprising a core disposed in the cavity, the one or more filaments being helically disposed around the core.

9. The electrode assembly according to claim 1 further comprising:

a biocompatible, electrically non-conductive and needle-piercable base;

the elongated electrically non-conductive body, with the one or more conductive filaments, being stitched to the needle-piercable base.

10. The electrode assembly of claim 1 wherein the insulation is configured so that the electrode assembly coupled with the active implantable medical device when in contact with the surrounding fluid has a capacitance in the range of 0.25 nanofarads to 3.30 nanofarads per metre.

11. The electrode assembly of claim 10 , wherein the insulation is a vapour deposited polymer coating or a Teflon coating.

12. A method of manufacturing an electrode assembly for an active implantable medical device, comprising:

providing an elongated biocompatible, electrically non-conductive body;

locating one or more biocompatible, electrically conductive filaments though the elongated non-conductive body from a first portion to a second portion;

forming one or more fluid passages along the elongated electrically non-conductive body between the first portion and the second portion, the one or more fluid passages allowing a surrounding fluid of a patient to be in contact with the one or more conductive filaments; and

forming one or more channels along the elongated electrically non-conductive body, the one or more channels providing the one or more fluid passages from an outer surface of the electrically non-conductive body to the one or more conductive filaments.

13. The method of manufacturing an electrode assembly according to claim 12 further comprising:

forming a plurality of apertures along the elongated electrically non-conductive body to provide the fluid passages from the outer surface of the electrically non-conductive body to the one or more conductive filaments.

14. The method of manufacturing an electrode assembly according to claim 12 , further comprising:

forming one or more conductive filament lumens inside the elongated electrically non-conductive body to receive respective electrically conductive filaments, the one or more conductive filament lumens having a diameter greater than the respective conductive filament lumens forming at least part of the one or more fluid passages.

15. The method of manufacturing an electrode assembly according to claim 12 , further comprising:

filling one or more fluid passages with one or more plugs, the plugs comprising a biocompatible biodegradable material, the one or more plugs biodegrading in a body of the patient after implantation.

16. The method of manufacturing an electrode assembly according to claim 12 , further comprising configuring insulation around the electrically conductive filaments such that the electrode assembly when coupled with the active implantable medical device and in contact with the surrounding fluid has a capacitance in the range of 0.25 nanofarads to 3.30 nanofarads per metre.

17. The method of manufacturing an electrode assembly according to claim 16 , further comprising insulating the one or more conductive filaments with a vapour deposited polymer coating or a Teflon coating.

18. An electrode assembly for an active implantable medical device comprising:

an elongated, biocompatible, electrically non-conductive body having a first portion and a second portion;

one or more biocompatible, electrically conductive filaments inside the elongated non-conductive body between the first portion and the second portion;

wherein the electrode assembly is configured to be coupled with the active implantable medical device and in contact with the surrounding fluid to have a capacitance in the range of 0.25 nanofarads to 3.30 nanofarads per metre.