Blocking Exogenous Action Potentials by an Implantable Medical Device

• US 20090270943A1
• Filed: 04/25/2008
• Published: 10/29/2009
• Est. Priority Date: 04/25/2008
• Status: Active Grant

• Current Assignee: LivaNova USA, Inc. (LivaNova Plc)
• Original Assignee: Cyberonics, Inc
• Inventors: Maschino, Steven E.
• Granted Patent: US 8,204,603 B2
• Time in Patent Office: Days
• US Class Current: 607/45
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362

Abstract

I disclose an implantable medical device (IMD) to treat a medical condition in a patient, comprising an electrical signal generator; a cathode and an anode operatively coupled to the electrical signal generator and a cranial nerve of the patient; and a third electrode operatively coupled to the electrical signal generator and implanted within the patient'"'"'s body; wherein the electrical signal generator is capable of generating and delivering at least one electrical signal effective at the anode to block at least a sufficient portion of action potentials induced by the at least one electrical signal in the cranial nerve proximate the cathode to reduce a side effect of said induced action potentials.

Claims

1. An implantable medical device (IMD) to treat a medical condition in a patient, comprising:

an electrical signal generator;

a cathode and an anode operatively coupled to the electrical signal generator and a cranial nerve of the patient;

a third electrode operatively coupled to the electrical signal generator and implanted within the patient'"'"'s body;

wherein;

the electrical signal generator is capable of generating and delivering at least one electrical signal effective at the anode to block at least a sufficient portion of action potentials induced by the at least one electrical signal in the cranial nerve proximate the cathode to reduce a side effect of said induced action potentials.

2. The implantable medical device of claim 1, wherein the electrical signal generator is capable of generating and delivering both (1) a first electrical signal to both the cathode and the anode in a first time period, wherein the first electrical signal is depolarizes the cranial nerve proximate the cathode and hyperpolarizes the cranial nerve proximate the anode;

and (2) a second electrical signal to both the anode and the third electrode in a second time period following the first time period, wherein the second electrical signal hyperpolarizes the cranial nerve proximate the anode for a duration sufficient to block at least a sufficient portion of action potentials induced by the at least one electrical signal in the cranial nerve proximate the cathode to reduce a side effect of said induced action potentials.

3. The implantable medical device of claim 2, wherein the second time period immediately follows the first time period.

4. The implantable medical device of claim 1, wherein the third electrode is not coupled to the cranial nerve.

5. The implantable medical device of claim 4, wherein the third electrode is the shell of the electrical signal generator.

6. The implantable medical device of claim 1, wherein the cranial nerve is the vagus nerve.

7. The implantable medical device of claim 1, further comprising a fourth electrode operatively coupled to a cranial nerve and the electrical signal generator.

8. A method of treating a medical condition in a patient using an implantable medical device, comprising:

providing an electrical signal generator,

coupling at least a cathode and an anode to a cranial nerve of the patient and to the electrical signal generator,

providing at least a third electrode implanted within the patient'"'"'s body and coupled to the electrical signal generator,

generating a first electrical signal with the electrical signal generator, and

delivering at least one electrical signal effective at the anode to block at least a sufficient portion of action potentials induced by the at least one electrical signal in the cranial nerve proximate the cathode to reduce a side effect of said induced action potentials.

9. The method of claim 8, wherein the side effect is selected from the group consisting of vocal cord modulation, breathing difficulty, shortness of breath, apnea, and dsypnea.

10. The method of claim 8, wherein at least a portion of the action potentials are blocked in one or more nerve fiber types selected from the group consisting of Aα

fibers, Aβ

fibers, Aγ

fibers, Aδ

fibers, B fibers, and C fibers.

11. The method of claim 8, wherein the blocked action potentials are efferent action potentials.

12. The method of claim 11, wherein the efferent action potentials stimulate muscle activity proximate the larynx.

13. The method of claim 8, wherein the electrical signal generator is capable of generating and delivering both (1) a first electrical signal to both the cathode and the anode in a first time period, wherein the first electrical signal depolarizes the cranial nerve proximate the cathode and hyperpolarizes the cranial nerve proximate the anode;

and (2) a second electrical signal to both the anode and the third electrode in a second time period following the first time period, wherein the second electrical signal hyperpolarizes the cranial nerve proximate the anode for a duration sufficient to block at least a sufficient portion of action potentials induced by the at least one electrical signal in the cranial nerve proximate the cathode to reduce a side effect of said induced action potentials.

14. The method of claim 13, wherein the duration of depolarization proximate the cathode is from about 0.01 msec to about 1 msec and the duration of hyperpolarization proximate the anode is from about 0.05 msec to about 5 msec.

15. The method of claim 8, further comprising charge balancing by passive discharge at at least one electrode selected from the group consisting of the cathode and the anode.

16. The method of claim 15, wherein passive discharge is performed at both the cathode and the anode.

17. The method of claim 8, further comprising charge balancing by active discharge at at least one electrode selected from the group consisting of the cathode and the anode.

18. The method of claim 17, wherein active discharge is performed at both the cathode and the anode.

19. In a method of neuromodulation effected by delivery of an exogenous electrical signal, using at least two electrodes, to a cranial nerve of a patient, the improvement comprising:

providing an electrical signal generator,

coupling at least a cathode and an anode to a cranial nerve of the patient and to the electrical signal generator,

providing at least a third electrode implanted within the patient'"'"'s body and coupled to the electrical signal generator,

generating a first electrical signal with the electrical signal generator, and

delivering at least one electrical signal effective at the anode to block at least a sufficient portion of action potentials induced by the at least one electrical signal in the cranial nerve proximate the cathode to reduce a side effect of said induced action potentials.

20. A system for treating a medical condition in a patient, comprising:

an electrical signal generator;

a cathode and an anode operatively coupled to the electrical signal generator and a cranial nerve of the patient;

a third electrode operatively coupled to the electrical signal generator and implanted within the patient'"'"'s body;

wherein;

the electrical signal generator is capable of generating and delivering at least one electrical signal effective at the anode to block at least a sufficient portion of action potentials induced by the at least one electrical signal in the cranial nerve proximate the cathode to reduce a side effect of said induced action potentials.

21. A method of treating a medical condition in a patient using an implantable medical device, comprising:

providing an electrical signal generator;

coupling at least a first electrode and a second electrode to a cranial nerve of the patient and to the electrical signal generator;

providing at least a third electrode implanted within the patient'"'"'s body, wherein said third electrode is coupled to the electrical signal generator and not coupled to the cranial nerve;

generating an electrical signal with the electrical signal generator, and

applying the electrical signal

to the first electrode for a first time interval corresponding to a depolarization phase at a first region of said cranial nerve;

to the second electrode for a second time interval corresponding to a hyperpolarization phase at a second region of said cranial nerve, wherein said second time interval exceeds said first time interval by a blocking time interval; and

to the third electrode for a blocking time interval following said first time interval, wherein said blocking time interval is sufficient for said second electrode to block at the second region of said cranial nerve substantially all action potentials generated by the depolarization phase at the first region of said cranial nerve.