Difibrillation electrodes and implantation

• US 5,411,527 A
• Filed: 08/31/1992
• Issued: 05/02/1995
• Est. Priority Date: 05/03/1989
• Status: Expired due to Fees

• Current Assignee: Advanced Medical Optics Incorporated (Johnson & Johnson)
• Original Assignee: Intermedics Incorporated
• Inventors: Alt, Eckhard
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US07/937,173
• Time in Patent Office: 974 Days
• Field of Search: 128/639-642, 128/644, 128/784-786, 128/419 P, 128/419 D, 607/5, 607/120, 607/122, 607/123, 607/129
• US Class Current: 607/5
• CPC Class Codes: A61N 1/0587 Epicardial electrode systems; Endocardial electrodes piercing the pericardium
• CPC Class Codes: A61N 1/3918 characterised by shock pathway, e.g. by electrode configuration
• CPC Class Codes: A61N 1/395 for treating atrial fibrillation

Abstract

An electrical lead has a cardioverting/defibrillating electrode composed of a multiplicity of tiny flexible elongate metallic fibers, for implantation in a patient. One embodiment of the lead is implanted by puncturing the chest/abdominal wall of the patient and inserting the lead, fiber electrode first, into the body through the puncture site followed by maneuvering the lead by endoscopy to position the electrode adjacent the epicardium of the heart for electrical interaction with the ventricles. The fibers may be interwoven to form a thin tube prestressed to assume a flat spiral shape to permit it to be straightened with a stiffening wire for maneuvering to return to its flat spiral shape after proper positioning and removal of the wire. In other embodiments, the lead has multiple conductors electrically connected to respective electrodes arranged on the lead for positioning transvenously relative to selected regions of the heart. For ventricular fibrillation, the arrangement is such that one electrode is positioned in the right ventricle and another in either the subclavian vein or pulmonary artery at the left side of the heart when the lead is fully implanted. For atrial fibrillation, the arrangement is such that one electrode is positioned in the right ventricle and another in the pulmonary artery adjacent the left atrium when the lead is fully implanted. The fibers of the electrode have a surface layer composed of electrically conductive carbon which may include a substance to inhibit thrombosis, inflammation and/or coagulation at the exposed surface of the electrode when the lead is implanted in the patient'"'"'s body.

Claims

1. A method for surgical implantation of an electrode in a patient for use in defibrillating the patient'"'"'s heart, which comprises:

selecting an electrical lead having at its distal end a defibrillation electrode composed of a multiplicity of fine, elongate, juxtaposed, individual, flexible conductive fibers each having an uncoated, relatively smooth surface layer of carbon derivative of substantially uniform thickness along substantially an entire length of each of said fibers to provide an overall electrode effective electrical surface area which is a cumulative effect of each surface area of the individual fibers and considerably greater than the geometric surface area of the electrode, for implantation in the patient'"'"'s body;

puncturing a preselected site in the chest/abdominal wall of the patient for insertion of the flexible fiber electrode and lead therein; and

inserting the flexible fiber electrode and lead through the puncture site, and maneuvering the inserted fiber electrode into position within the patient'"'"'s body to encompass a portion of the ventricular mass of the heart for electrical stimulation of the ventricles when the electrode is energized, while viewing the maneuvering externally on a visual internal body scanner.

2. The method of claim 1, wherein the viewing is performed by endoscopy.

3. The method of claim 1, wherein the defibrillation electrode is a tube composed of interwoven fibers prestressed to assume a flat coiled shape when unrestrained, including maneuvering the tube into position with a straightening wire therein, and withdrawing the straightening wire after the electrode is properly positioned to allow the defibrillation electrode to return to its flat coiled shape at a preselected location.

4. The method of claim 3, including positioning the defibrillation electrode within the pericardial sac.

5. The method of claim 4, further including puncturing the pericardial sac for insertion of the defibrillating electrode therein while the straightening wire is within the tube.

6. The method of claim 1, including

selecting said fiber electrode formed from a bundle of generally interwoven fibers secured together at one end and free of one another at the other end, so that each fiber has a considerable length of its free end unconnected to the adjacent corresponding free end of the other fibers in the bundle, whereby to form a fan-shaped electrode when positioned adjacent the heart.

7. The method of claim 1, including

selecting said fiber electrode formed from conductive fibers each having a carbon surface, and having the carbon surface of the fibers impregnated with an antithrombin or antiinflammatory substance prior to implantation, to inhibit fibrotic growth along substantially an entire surface of the electrode which is exposed to blood and tissue when implanted in the patient'"'"'s body.

8. The method of claim 1, including

selecting said fiber electrode formed from a multiplicity of woven strands of tiny individual elongate uninsulated fibers composed of substantially isotropic electrically conductive material electrically connected to said lead, so that the electrode provides an electron-ion interface with blood and/or body tissue for efficient transfer of electrical energy along an entire substantial length of uninsulated surface of the fibers, in which the surface of the fibers cumulatively presents an effective electrical surface area considerably greater than the actual geometric surface area calculated from the linear dimensions of the electrode.

9. The method of claim 8, including

selecting said electrode in which the electrode fibers have a carbon surface impregnated with a substance which acts to suppress the formation of fibrotic connective tissue over time at an exposed surface of the electrode when implanted in the patient'"'"'s body.

10. A method for defibrillating the heart of a patient, comprising the steps of:

implanting in the patient an electrical lead having a proximal end and a distal end, and having at its distal end a flexible electrode composed of conductive fibers each having an uncoated carbon surface,

and in which the carbon surface of substantially each of the fibers is impregnated to bond with molecules of a substance selected to inhibit growth of fibrotic connective tissue at each impregnated surface of the electrode exposed to blood and tissue when implanted in the patient'"'"'s body,

positioning the implanted electrode relative to the patient'"'"'s heart for use in defibrillating the heart when the electrode is energized with a defibrillating electrical waveform, and

electrically connecting the proximal end of the lead to a source of said defibrillating electrical waveform.

11. The method of claim 10, including selecting a flexible electrode in which the growth-inhibiting substance is heparin.

12. The method of claim 10, including selecting a flexible electrode in which the growth-inhibiting substance is hirudin.

13. The method of claim 10, including selecting a flexible electrode in which the growth-inhibiting substance is a steroid drug.

14. The method of claim 10, including arranging the fibers of the flexible electrode in an array to encompass a portion of the epicardial surface of the patient'"'"'s heart adjacent a heart chamber to be defibrillated, when the electrode is implanted.

15. The method of claim 14, wherein the flexible electrode is a tubular configuration of interwoven isotropic conductive fiber strands, and including prestressing the configuration to assume a flat coiled shape when unrestrained.

16. A lead assembly for use in defibrillating the heart of a patient in which the lead assembly is to be implanted, comprising:

an electrically conductive lead wire having a proximal end and a distal end,

a flexible stimulating electrode composed of a multiplicity of fine, elongate, electrically conductive fibers each having an uncoated carbon surface of substantially uniform thickness over substantially its entire length, the electrode being electrically connected to the distal end of the lead wire for implantation in the patient'"'"'s body and adapted, when the electrode is implanted at a selected site in the patient'"'"'s body and the proximal end of the lead wire is connected to a defibrillator, to accept electrical energization of sufficient magnitude to defibrillate the heart, and

a substance incorporated into the carbon surface of the fibers of the electrode in a molecular bond with and not a coating of the carbon surface to impede the growth of fibrotic connective tissue at a surface of the electrode exposed to blood and tissue when implanted in the patient'"'"'s body.

17. The lead assembly of claim 16, wherein said substance is heparin.

18. The lead assembly of claim 16, wherein said substance is hirudin.

19. The lead assembly of claim 16, wherein said substance is a steroid.

20. An implantable lead for use in cardioversion or defibrillation of a human heart, comprising:

an elongate electrical conductor, and

an electrode electrically connected to the conductor, the electrode including;

a multiplicity of juxtaposed, fine, uninsulated, elongate, individual, flexible metallic fibers each of a diameter considerably smaller than its length, and of sufficient number to provide an overall effective electrically conductive surface area formed by individual surfaces of the multiplicity of fibers considerably greater than the outer geometrical surface area encompassing the electrode and capable of being non-destructively energized by electrical waveforms of magnitude and other characteristics suitable to defibrillate a human heart, and

maintaining means for holding the multiplicity of fibers in a flexible configuration having a shape and size selected according to an intended location of the electrode when the lead is implanted for use in cardioversion or defibrillation of the heart.

21. The implantable lead of claim 20, wherein:

said maintaining means comprises the fibers themselves interwoven into said shape and size.

22. The implantable lead of claim 20, wherein:

the fibers have a surface layer composed of an electrically conductive carbon derivative.

24. The implantable lead of claim 20, wherein:

the fibers are composed of a platinum iridium alloy.

25. The implantable lead of claim 24, wherein:

each fiber is a strand of said platinum iridium alloy of approximately 27 microns in diameter.

26. The implantable lead of claim 25, wherein:

said fibers are arranged in multi-strand bundles of nine strands each, and a plurality of said bundles are braided to form said electrode.

27. An implantable lead for use in cardioversion or defibrillation of a human heart, comprising:

an elongate electrical conductor, and

an electrode electrically connected to the conductor, the electrode including;

a multiplicity of individual, flexible metallic fibers each of a diameter considerably smaller than its length, each fiber having a surface layer composed of a substantially isotropic electrically conductive carbon derivative, to provide an overall effective electrically conductive surface area formed by the individual surfaces of the multiplicity of fibers considerably greater than the outer geometrical surface area encompassing the electrode, and

maintaining means for holding the multiplicity of fibers in a flexible configuration having a shape and size selected according to an intended location of the electrode when the lead is implanted for use in cardioversion or defibrillation of the heart.

23. The implantable lead of claim 27, wherein:

said surface layers is impregnated with a substance for impeding at least one of thrombosis, inflammation, and coagulation at the electrode surface when the lead is implanted.

28. The implantable lead of claim 27, wherein:

said maintaining means comprises the fibers themselves interwoven into said shape and size.

29. The implantable lead of claim 27, wherein:

said surface layer includes means for impeding at least one of thrombosis, inflammation, and coagulation at the electrode surface when the lead is implanted.

30. The implantable lead of claim 27, wherein:

the fibers are composed of a platinum iridium alloy.

31. The implantable lead of claim 301, wherein:

said fibers are arranged in multi-strand bundles, each strand being composed of said alloy and having a diameter in a range from about 10 to about 30 microns, and a plurality of said bundles are braided to form said electrode.