Implantable device for providing electrical stimulation of cervical vagus nerves for treatment of chronic cardiac dysfunction with leadless heart rate monitoring

• US 8,923,990 B2
• Filed: 04/26/2013
• Issued: 12/30/2014
• Est. Priority Date: 12/07/2011
• Status: Active Grant

• Current Assignee: LivaNova USA, Inc. (LivaNova Plc)
• Original Assignee: Cyberonics, Inc
• Inventors: Libbus, Imad, Amurthur, Badri, Kenknight, Bruce H.
• Primary Examiner(s): Koharski, Christopher D
• Assistant Examiner(s): CAREY, MICHAEL JAMES
• Application Number:
  US13/872,004
• Publication Number:
  US 20130238047A1
• Time in Patent Office: 613 Days
• Field of Search: 607/116, 607/118
• US Class Current: 607/118
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36139 with automatic adjustment
• CPC Class Codes: A61N 1/36175 Pulse width or duty cycle
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

An implantable device for providing electrical stimulation of cervical vagus nerves for treatment of chronic cardiac dysfunction with leadless heart rate monitoring is provided. A stimulation therapy lead includes helical electrodes configured to conform to an outer diameter of a cervical vagus nerve sheath, and a set of connector pins electrically connected to the helical electrodes. The neurostimulator includes a pulse generator configured to therapeutically stimulate the vagus nerve through the helical electrodes in alternating cycles of stimuli application and stimuli inhibition that are tuned to both efferently activate the heart'"'"'s intrinsic nervous system and afferently activate the patient'"'"'s central reflexes by triggering bi-directional action potentials. The neurostimulator includes an integrated leadless heart rate sensor configured to sense heart rate and to record the sensed heart rate as data into a memory.

Claims

1. A method of treating a patient having chronic heart failure (CHF), the method comprising:

generating a pulsed electrical signal comprising;

a signal ON time;

a signal OFF time;

an output current;

a signal frequency of at least 10 Hz;

a pulse width; and

a duty cycle defined by dividing the signal ON time by the sum of the signal ON time and signal OFF time, wherein the duty cycle comprises a value in the range of 5% to 30%;

applying the electrical signal to a vagus nerve using at least one electrode coupled to said vagus nerve, wherein the application of the electrical signal to the vagus nerve results in propagation of action potentials in both afferent and efferent directions, wherein said afferent action potentials activate one or more medial medullary sites and said efferent action potentials activate the intrinsic nervous system of the heart;

sensing the heart rate of the patient; and

analyzing said heart rate of the patient to determine at least one of a therapeutic efficacy and a patient condition.

2. The method of claim 1 wherein analyzing said heart rate comprises determining a plurality of heart rate data statistics over a stated time period.

3. The method of claim 1 wherein applying said electrical signal further comprises at least one acute indication of efficacy selected from:

an increase in heart rate variability;

an increase in coronary flow;

a reduction in cardiac workload; and

improvement in left ventricular relaxation.

4. The method of claim 3 further comprising:

determining a targeted acute measure of therapeutic efficacy;

weighting each of the acute indications of efficacy; and

analyzing the weighted acute indications of efficacy relative to the targeted therapeutic efficacy to determine a preferred duty cycle.

5. The method of claim 1 wherein applying said electrical signal further comprises at least one chronic indication of efficacy selected from:

decreased sympathetic activation;

increased parasympathetic activation;

decreased negative cytokine production;

increased baroreflex sensitivity;

increased respiratory gas exchange efficiency;

favorable gene expression;

renin-angiotensin-aldosterone system down-regulation; and

anti-inflammatory effects.

6. The method of claim 5 further comprising:

determining a targeted chronic measure of therapeutic efficacy;

weighting each of the chronic indications of efficacy; and

analyzing the weighted chronic indications of efficacy relative to the targeted therapeutic efficacy to determine a preferred duty cycle.

7. The method of claim 1 wherein said signal frequency is about 20 Hz.

8. The method of claim 1 wherein sensing the heart rate of the patient comprises sensing the patient heart rate during the signal OFF time.

9. The method of claim 1 wherein the vagus nerve comprises a superior cervical cardiac branch and an inferior cervical cardiac branch, the method further comprising coupling the at least one electrode to the vagus nerve below where the superior cervical cardiac branch and inferior cervical cardiac branch separate from the vagus nerve.

10. A method of treating chronic cardiac dysfunction of a patient having a vagus nerve, a brain, and a heart, the method comprising:

generating an electrical signal at a pulse generator, wherein the electrical signal comprises;

a 5% to 30% periodic duty cycle, wherein the periodic duty cycle comprises a percentage of time that the pulse generator is generating the electrical signal; and

signal parameters, wherein the signal parameters comprise at least one of;

an output current;

a signal frequency of at least 10 Hz; and

a pulse width;

communicating the electrical signal to an electrode assembly coupled to the vagus nerve of the patient;

applying the electrical signal to the vagus nerve, wherein the application of the electrical signal to the vagus nerve propagates bi-directional action potential in the vagus nerve;

detecting at least a portion of a cardiac cycle of the patient, wherein the at least a portion of the cardiac cycle is detected by a leadless heart rate sensor communicatively coupled to the pulse generator; and

logging the at least a portion of the cardiac cycle of the patient in a memory.

11. The method of claim 10, wherein the leadless heart rate sensor is integrated within the pulse generator.

12. The method of claim 10, wherein the bi-directional action potential comprises both afferent propagating action potential that activates medial medullary sites responsible for central reflex control within the brain and efferent propagating action potential that activate the intrinsic nervous system of the heart.

13. The method of claim 10 further comprising:

analyzing the logged portion of the cardiac cycle of the patient to determine at least one of a therapeutic efficacy and a patient condition.

14. The method of claim 13 wherein analyzing the logged portion of the cardiac cycle comprises determining a plurality of heart rate data statistics over a stated time period.

15. The method of claim 10 wherein applying the electrical signal further comprises at least one acute indication of efficacy selected from:

an increase in heart rate variability;

an increase in coronary flow;

a reduction in cardiac workload; and

improvement in left ventricular relaxation.

16. The method of claim 15 further comprising:

determining a targeted acute measure of therapeutic efficacy;

weighting each of the acute indications of efficacy; and

analyzing the weighted acute indications of efficacy relative to the targeted therapeutic efficacy to determine a preferred duty cycle.

17. The method of claim 10 wherein applying said electrical signal further comprises at least one chronic indication of efficacy selected from:

decreased sympathetic activation;

increased parasympathetic activation;

decreased negative cytokine production;

increased baroreflex sensitivity;

increased respiratory gas exchange efficiency;

favorable gene expression;

renin-angiotensin-aldosterone system down-regulation; and

anti-inflammatory effects.

18. The method of claim 17 further comprising:

determining a targeted chronic measure of therapeutic efficacy;

weighting each of the chronic indications of efficacy; and

analyzing the weighted chronic indications of efficacy relative to the targeted therapeutic efficacy to determine a preferred duty cycle.

19. The method of claim 10 wherein the signal frequency is about 20 Hz.

20. A method of treating a patient having chronic heart failure (CHF), the method comprising:

generating a pulsed electrical signal comprising;

a signal ON time;

a signal OFF time;

an output current;

a signal frequency of at least 10 Hz;

a pulse width; and

a duty cycle defined by dividing the signal ON time by the sum of the signal ON time and signal OFF time, wherein the duty cycle comprises a value in the range of 5% to 30%;

coupling at least one electrode to a vagus nerve comprising a superior cervical cardiac branch and an inferior cervical cardiac branch, wherein the at least one electrode is coupled to the vagus nerve below where the superior cervical cardiac branch and inferior cervical cardiac branch separate from the vagus nerve;

applying the electrical signal to the vagus nerve, wherein the application of the electrical signal to the vagus nerve results in propagation of action potentials in both afferent and efferent directions, wherein said afferent action potentials activate one or more medial medullary sites and said efferent action potentials activate the intrinsic nervous system of the heart;

sensing the heart rate of the patient; and

analyzing said heart rate of the patient to determine at least one of a therapeutic efficacy and a patient condition.