ELECTRICAL INIBITION OF THE PHRENIC NERVE DURING CARDIAC PACING

• US 20110152956A1
• Filed: 12/08/2010
• Published: 06/23/2011
• Est. Priority Date: 12/17/2009
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Rockweiler, Holly, Hincapie Ordonez, Juan Gabriel
• Granted Patent: US 8,620,428 B2
• Time in Patent Office: Days
• US Class Current: 607/4
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1107 Measuring contraction of parts of the body, e.g. organ, muscle apparatus for measuring work or force in general G01L
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/388 Nerve conduction study, e.g. detecting action potential of peripheral nerves
• CPC Class Codes: A61B 5/4041 Evaluating nerves condition
• CPC Class Codes: A61N 1/3601 of respiratory organs
• CPC Class Codes: A61N 1/36167 Timing, e.g. stimulation onset
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold

Abstract

According to various method embodiments for pacing a heart and avoiding unwanted stimulation of a phrenic nerve during cardiac pacing, a desired pacing time for delivering a cardiac pace is determined, and a desired nerve traffic inhibition time to inhibit nerve traffic in the phrenic nerve is determined using the desired pace time. The cardiac pace is delivered at the desired pacing time and nerve traffic in the phrenic nerve is inhibited at the desired nerve traffic inhibition time.

Claims

1. A system for pacing a heart and avoiding unwanted stimulation of a phrenic nerve, comprising:

a cardiac pulse generator configured to generate cardiac paces to pace the heart;

a nerve traffic inhibitor configured to generate an electrical signal to inhibit nerve traffic in the phrenic nerve;

a cardiac activity sensor configured to sense cardiac activity;

a controller operably connected to the cardiac pulse generator, the nerve traffic inhibitor, and the cardiac activity sensor,

wherein the controller includes a cardiac pacing timer and a nerve traffic inhibition timer,

wherein the controller is configured to use sensed cardiac activity and the cardiac pacing timer to determine a desired pace time for a cardiac pace, and

wherein the controller is configured to use the desired pace time and the nerve traffic inhibition timer to control the nerve traffic inhibitor to inhibit nerve traffic in the phrenic nerve at a desired inhibition time with respect to the desired pace time to prevent the cardiac pace from stimulating the phrenic nerve.

2. The system of claim 1, wherein the nerve traffic inhibitor is configured to deliver a hyperpolarizing DC current pulse to modify the excitability of the nerve axons in the phrenic nerve at the desired inhibition time.

3. The system of claim 1, wherein the nerve traffic inhibitor is configured to deliver a depolarizing DC current pulse to modify the excitability of nerve axons in the phrenic nerve at the desired inhibition time but without enough strength to generate propagated action potentials.

4. The system of claim 1, wherein the nerve traffic inhibitor is configured to deliver pulses at a frequency effectively high to modify the excitability of the nerve axons in the phrenic nerve at the desired inhibition time.

5. The system of claim 1, further comprising a left ventricular lead configured to position at least one left ventricular pacing electrode to pace a left ventricle of the heart, wherein the cardiac pulse generator is configured to use the left ventricle lead to deliver pacing pulses to the left ventricle, and wherein the phrenic nerve is a left phrenic nerve.

6. The system of claim 5, further comprising at least one lead configured to position at least one right ventricular electrode to pace the right ventricle, wherein the cardiac pulse generator is configured to generate pacing pulses to pace the right ventricle using the right ventricular electrode and to pace the left ventricle using the left ventricular electrode, and wherein the controller is configured to appropriately time paces to the right and left ventricle to perform a cardiac resynchronization therapy (CRT).

7. The system of claim 5, wherein the nerve traffic inhibitor is configured to use the left ventricular electrode to inhibit nerve traffic in the phrenic nerve.

8. The system of claim 5, wherein the left ventricle lead includes at least two electrodes, wherein the cardiac pulse generator is configured to pace the left ventricle using one of the at least two electrodes on the left ventricle lead and is configured to inhibit nerve traffic in the left phrenic nerve using another one of the at least two electrodes on the left ventricle lead.

9. The system of claim 5, further comprising a phrenic nerve lead with at least one inhibition electrode, wherein the phrenic nerve lead is configured to place the at least one inhibition electrode operationally proximate to the phrenic nerve for use in inhibiting nerve traffic in the phrenic nerve.

10. The system of claim 9, wherein the phrenic nerve lead is a first phrenic nerve lead, the system further comprising at least a second phrenic nerve lead with at least one inhibition electrode, wherein the first and second phrenic nerve leads are fed into at least a first and a second cardiac vein to place the inhibition electrodes in the first and second cardiac veins, and wherein the inhibition electrodes in the first and second cardiac veins are used to inhibit nerve traffic in the phrenic nerve.

11. The system of claim 9, wherein the phrenic nerve lead is configured to feed the at least one inhibition electrode into a coronary sinus tributary into a position operationally proximate to the phrenic nerve, and wherein the nerve traffic inhibitor is configured to deliver the electric signal to inhibit nerve traffic in the phrenic nerve using the at least one inhibition electrode in the coronary sinus tributary.

12. The system of claim 9, wherein the at least one inhibition electrode includes a nerve cuff electrode or a diaphragm epimysial electrode.

13. The system of claim 1, further comprising a respiration detector configured to detect a respiration cycle, wherein the controller is configured to use the detected respiration cycle to determine the desired inhibition time.

14. The system of claim 1, further comprising a context detector configured to detect a contextual event and provide an enable signal to the controller when the contextual event is detected, wherein the context detector includes a physiological sensor or clock, and wherein the controller is configured to control the nerve traffic inhibitor to inhibit nerve traffic in the phrenic nerve only for a time period after the contextual event is detected.

15. The system of claim 14, wherein the physiological sensor is an unintended phrenic nerve activity detector configured to detect pace-induced phrenic nerve activity, and wherein the controller is configured to control the nerve traffic inhibitor to inhibit nerve traffic in the phrenic nerve after the unintended phrenic nerve activity detector detects the pace-induced phrenic nerve activity.

16. A method for avoiding unwanted stimulation of a phrenic nerve during cardiac pacing, comprising:

receiving a desired pace time for delivering a cardiac pace;

determining a desired nerve traffic inhibition time to inhibit nerve traffic in the phrenic nerve, wherein determining the desired nerve traffic inhibition time includes using the desired pace time to determine the desired nerve traffic inhibition time; and

inhibiting nerve traffic in the phrenic nerve at the desired nerve traffic inhibition time.

17. The method of claim 16, wherein inhibiting nerve traffic includes:

delivering a DC current pulse to hyperpolarize nerve axons in the phrenic nerve at the desired inhibition time;

or

delivering a depolarizing DC current pulse to modify the excitability of nerve axons in the phrenic nerve at the desired inhibition time but without enough strength to generate propagated action potentials;

or

delivering pulses at a pulse frequency where the frequency is effectively high to modify the excitability of the nerve axons in the phrenic nerve at the desired inhibition time.

18. The method of claim 16, wherein inhibiting nerve traffic includes using at least one electrode in a coronary sinus tributary to inhibit nerve traffic in the phrenic nerve.

19. The method of claim 16, further comprising detecting pace-induced phrenic nerve activity, and wherein inhibiting nerve traffic includes implementing a process, in response to detecting the pace-induced phrenic nerve activity, to inhibit nerve traffic in the phrenic nerve.

20. The method of claim 16, further comprising detecting a respiration cycle, wherein inhibiting nerve traffic includes implementing a process to inhibit nerve traffic only for a portion of the detected respiration cycle.

21. A method for pacing a heart and avoiding unwanted stimulation of a phrenic nerve during cardiac pacing, comprising:

determining a desired pacing time for delivering a cardiac pace;

determining a desired nerve traffic inhibition time to inhibit nerve traffic in the phrenic nerve, wherein determining the desired nerve traffic inhibition time includes using the desired pace time to determine the desired nerve traffic inhibition time; and

delivering the cardiac pace at the desired pacing time and inhibiting nerve traffic in the phrenic nerve at the desired nerve traffic inhibition time.

22. The method of claim 21, wherein:

delivering the cardiac pace includes delivering the cardiac pace to a left ventricle of the heart; and

inhibiting nerve traffic in the phrenic nerve includes inhibiting nerve traffic in a left phrenic nerve.

23. The method of claim 22, further comprising delivering cardiac resynchronization therapy (CRT), wherein delivering the CRT includes delivering the cardiac pace to a left ventricle of the heart.

24. The method of claim 22, further comprising using a common lead within a coronary sinus tributary to deliver the cardiac pace to the left ventricle and to inhibit nerve traffic in the left phrenic nerve.

25. The method of claim 21, wherein the desired nerve traffic inhibition time is initiated before or during the desired pace time.