SYSTEM AND METHOD FOR TESTING NEURAL STIMULATION THRESHOLD

• US 20100318154A1
• Filed: 08/23/2010
• Published: 12/16/2010
• Est. Priority Date: 04/10/2006
• Status: Active Grant

• Current Assignee: Andrew P. Kramer, Imad Libbus
• Original Assignee: Andrew P. Kramer, Imad Libbus
• Inventors: Kramer, Andrew P., Libbus, Imad
• Granted Patent: US 7,894,895 B2
• Time in Patent Office: Days
• US Class Current: 607/28
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36117 for treating hypertension

Abstract

Various system embodiments comprise a neural stimulator, a premature ventricular contraction (PVC) event detector, a heart rate detector, an analyzer, and a controller. The neural stimulator is adapted to generate a stimulation signal adapted to stimulate an autonomic neural target. The analyzer is adapted to, in response to a PVC event signal from the PVC event detector, generate an autonomic balance indicator (ABI) as a function of pre-PVC heart rate data and post-PVC heart rate data. Other aspects and embodiments are provided herein.

Claims

1. A method for modulating autonomic balance between parasympathetic tone and sympathetic tone in an autonomic nervous system (ANS), the method comprising:

stimulating an autonomic neural target to modulate the autonomic balance in the ANS;

performing a neural stimulation threshold test in response to a demand for the neural stimulation threshold test, wherein performing the neural stimulation threshold test includes;

inducing a premature ventricular contraction (PVC) event or detecting an intrinsic PVC event;

detecting pre-PVC heart rate data and post-PVC heart rate data;

measuring heart rate turbulence (HRT) in response to the PVC event using the pre-PVC heart rate data and the post-PVC heart rate data to generate an autonomic balance indicator (ABI); and

using the ABI to determine whether the neural stimulation signal evokes a response above a threshold.

2. The method of claim 1, wherein performing a neural stimulation threshold test in response to a demand for the neural stimulation threshold test includes performing the neural stimulation threshold test based on a time trigger.

3. The method of claim 1, wherein performing a neural stimulation threshold test in response to a demand for the neural stimulation threshold test includes performing the neural stimulation threshold test based on a detected event trigger.

4. The method of claim 1, wherein performing a neural stimulation threshold test in response to a demand for the neural stimulation threshold test includes performing the neural stimulation threshold test based on a clinician-generated command.

5. The method of claim 1, further comprising reporting the ABI to a clinician to inform the clinician if the neural stimulation signal evokes a response above the threshold.

6. The method of claim 1, wherein inducing the PVC event includes pacing a ventricle.

7. The method of claim 1, performing the neural stimulation threshold test includes performing a process to detect the intrinsic PVC, and inducing the PVC event if the intrinsic PVC is not detected within a predetermined time.

8. The method of claim 1, wherein using the ABI to determine whether the neural stimulation signal evokes a response above a threshold includes using a plurality of ABIs to determine whether the neural stimulation signal evokes a response above a threshold.

9. The method of claim 1, further comprising performing an autocapture routine to automatically adjust stimulation parameters of the stimulation signal to stimulate the autonomic neural target based on results of the neural stimulation capture test.

10. The method of claim 1, further comprising changing the autonomic neural target to be stimulated based on results of the neural stimulation capture test.

11. The method of claim 1, further comprising changing a stimulation vector based on results of the neural stimulation capture test.

12. The method of claim 1, further comprising changing an intensity of the stimulation based on results of the neural stimulation capture test.

13. The method of claim 1, further comprising applying rules or criteria to select valid PVCs, and applying rules or criteria to select valid R-R intervals used to detect the pre-PVC heart rate data and the post-PVC heart rate data.

14. The method of claim 1, wherein stimulating the autonomic neural target includes generating stimulation bursts, and wherein measuring HRT includes measuring HRT during a time between successive stimulation bursts when the stimulation signal is not generated.

15. The method of claim 1, wherein stimulating the autonomic neural target includes generating stimulation bursts, and wherein measuring HRT includes:

measuring HRT for a time that includes a beginning of one of the stimulation bursts to reflect heart rate from a time without neural stimulation to a time with neural stimulation;

or measuring HRT includes measuring HRT for a time that includes an end of one of the stimulation bursts to reflect heart rate from a time with neural stimulation to a time without neural stimulation.

16. A neural stimulation system to modulate autonomic balance between parasympathetic tone and sympathetic tone in an autonomic nervous system (ANS), the system comprising:

a neural stimulator configured to stimulate an autonomic neural target to modulate the autonomic balance in the ANS;

a premature ventricular contraction (PVC) stimulator configured to induce a PVC using a ventricular pacing pulse;

a heart rate detector configured to detect heart both before and after the induced PVC;

an analyzer connected to the heart rate detector and configured to measure heart rate turbulence (HRT) using pre-PVC heart rate data and post-PVC heart rate data to generate an autonomic balance indicator (ABI); and

a controller configured to;

control the neural stimulator to generate a neural stimulation signal to stimulate the autonomic neural target;

receive or generate a triggering signal representing a demand for a neural stimulation threshold test;

control the PVC stimulator in response to the triggering signal to induce the PVC; and

receive the ABI from the analyzer for the induced PVC, wherein the received ABI indicates whether the neural stimulation signal evokes a response above a threshold.

17. The system of claim 16, wherein the controller is configured to automatically evaluate whether the neural stimulation signal evokes the response above the threshold, to adjust the neural stimulation signal if the neural stimulation signal did not evoke the response above the threshold, and generate another triggering signal to demand another neural stimulation threshold test for the adjusted neural stimulation signal.

18. The system of claim 16, wherein the controller is adapted to make an adjustment to the neural stimulation therapy using at least two of ABIs.

19. The system of claim 16, further comprising communication circuitry configured to communicate with a programmer configured for use by a clinician to program the neural stimulator, wherein the controller and the communication circuitry are configured to cooperate to communicate the received ABI to the programmer.

20. The system of claim 16, further comprising communication circuitry configured to communicate with a programmer, wherein the controller and communication circuitry are configured to receive the triggering signal from the programmer.

21. The system of claim 16, further comprising a timer, wherein the controller and timer are configured to generate the triggering signal based on time.

22. The system of claim 16, further comprising an event detector, wherein the controller and timer are configured to generate the triggering signal based on a detected event.

23. The system of claim 16, wherein the neural stimulator, the PVC stimulator, the heart rate detector, the analyzer, and the controller are housed in a single implantable medical device.

24. The system of claim 16, further comprising an implantable neural stimulator device and an implantable cardiac rhythm management (CRM) device adapted to communicate with each other, the implantable neural stimulator device including at least the neural stimulator and the controller, the implantable CRM device including at least the PVC stimulator.

25. The system of claim 16, wherein:

the analyzer is adapted to generate a plurality of ABIs; and

the controller is adapted to average or trend the plurality ABIs, and to control the neural stimulating using the average or trend of the plurality of ABIs to achieve the desired autonomic balance for the ANS.

26. The system of claim 16, wherein the PVC event detector is adapted to apply rules or criteria to select valid PVCs and to select valid R-R intervals used to determine pre-PVC and post-PVC heart rate data.

27. The system of claim 16, wherein the controller and the neural stimulator are configured to chronically deliver an intermittent neural stimulation therapy with stimulation bursts, and wherein the system is configured to measure HRT for a time between successive stimulation bursts when the stimulation signal is not generated.

28. The system of claim 16, wherein the controller and the neural stimulator are configured to chronically deliver an intermittent neural stimulation therapy with stimulation bursts, and wherein the system is configured to measure HRT for a time that includes a beginning of one of the stimulation bursts to reflect heart rate from a time without neural stimulation to a time with neural stimulation, or for a time that includes an end of one of the stimulation bursts to reflect heart rate from a time with neural stimulation to a time without neural stimulation.