Remote pace detection in an implantable medical device

• US 8,301,241 B2
• Filed: 07/13/2010
• Issued: 10/30/2012
• Est. Priority Date: 07/15/2009
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Ternes, David J., Baker, Kenneth L.
• Primary Examiner(s): Manuel, George
• Assistant Examiner(s): WIELAND, ROBERT N
• Application Number:
  US12/835,308
• Publication Number:
  US 20110015703A1
• Time in Patent Office: 840 Days
• Field of Search: 607/2, 607/3, 607/4, 607/9, 607/11, 607/17, 607/20, 607/21, 607/45, 607/14, 607/116
• US Class Current: 607/2
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• 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 1/36146 specified by the stimulation parameters
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient
• CPC Class Codes: G16H 20/10 relating to drugs or medications, e.g. for ensuring correct administration to patients
• CPC Class Codes: G16H 20/70 relating to mental therapies, e.g. psychological therapy or autogenous training
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 40/67 for remote operation

Abstract

A system embodiment for stimulating a neural target comprises a neural stimulator, a pace detector, and a controller. The neural stimulator is electrically connected to at least one electrode, and is configured to deliver a neural stimulation signal through the at least one electrode to stimulate the neural target. The pace detector is configured to use at least one electrode to sense cardiac activity and distinguish paced cardiac activity in the sensed cardiac activity from non-paced cardiac activity in the sensed cardiac activity. The controller is configured to control a programmed neural stimulation therapy using the neural stimulator and using detected paced cardiac activity as an input for the neural stimulation therapy.

Claims

1. A system for stimulating a neural target, comprising:

a neural stimulator electrically connected to at least one electrode, wherein the neural stimulator is configured to deliver a neural stimulation signal through the at least one electrode to stimulate the neural target;

a pace detector configured to use at least one electrode to sense cardiac activity and distinguish paced cardiac activity in the sensed cardiac activity from non-paced cardiac activity in the sensed cardiac activity; and

a controller configured to control a programmed neural stimulation therapy using the neural stimulator and using detected paced cardiac activity as an input for the neural stimulation therapy.

2. The system of claim 1, wherein the pace detector includes:

a first comparator configured to compare sensed cardiac activity to a positive threshold and generate a first signal if a rising edge of the sensed cardiac activity is more positive than the positive threshold; and

a second comparator configured to compare sensed cardiac activity to a negative threshold and generate a second signal if a falling edge of the sensed cardiac activity is more negative than the negative threshold.

3. The system of claim 1, further comprising:

a first cascaded amplifier, the first cascaded amplifier including the first comparator; and

a second cascaded amplifier, the second cascaded amplifier including the second comparator.

4. The system of claim 3, further comprising a first sample and hold circuit to receive the first signal from the first comparator and a second sample and hold circuit to receive the second signal from the second comparator.

5. The system of claim 1, wherein the pace detector is configured to detect overdrive pacing in the sensed cardiac activity.

6. The system of claim 5, wherein the controller is configured to interrupt or modify the neural stimulation therapy in response to detected overdrive pacing.

7. The system of claim 6, wherein the controller is configured to return to an unmodified neural stimulation therapy when overdrive pacing is no longer detected or when an antiarrhythmia shock is detected, or after expiration of a post overdrive pacing period.

8. The system of claim 5, wherein the controller is configured to:

initiate a first timer;

detect a first pace after the first timer expired;

initiate a second timer when the first pace is detected;

detect a second pace before the second timer expired, increment a count in response to the detected second pace, reinitiate the second timer in expectation for a subsequent pace, and compare the count to a threshold for declaring antitachycardia pacing; and

detect the subsequent pace before the reinitiated second timer expires, increment the count in response to the detected subsequent pace, and compare the count to a threshold for declaring overdrive pacing.

9. The system of claim 8, wherein the first timer is approximately 5 seconds and the second timer is approximately 330 ms or less to detect a rapid series of pacing.

10. The system of claim 1, wherein the pace detector is configured to distinguish paced right atrial activity from paced right ventricle activity, or is configured to detect biventricular pacing and subsequent loss of the biventricular pacing.

11. The system of claim 1, wherein the programmed neural stimulation therapy has a duty cycle with a stimulation ON portion and a stimulation OFF portion, and the controller is configured to distinguish between detected paces during the stimulation ON portion and detected paces during the stimulation OFF portion.

12. The system of claim 11, wherein the controller is configured to modify the neural stimulation therapy using the detected paces during the stimulation ON portion and the detected paces during the stimulation OFF portion.

13. The system of claim 1, wherein the pace detector is configured to monitor pulse widths to determine a pace location of a detected pace, wherein different pacing pulse widths are used for different locations.

14. The system of claim 1, wherein the pace detector is configured to analyze sensed cardiac activity to identify at least one ECG component, and to identify a detected pace using the identified ECG components, wherein the at least one ECG component includes a QRS wave, a P-wave, a T-wave or AV delays.

15. A method for operating an implanted neural stimulation device, comprising:

using a pace detector in the implanted neural stimulation device, sensing cardiac activity and distinguishing between paced cardiac activity and non-paced cardiac activity; and

controlling a programmed neural stimulation therapy performed by the implanted neural stimulation device using detected cardiac activity as an input for the neural stimulation therapy.

16. The method of claim 15, further comprising detecting R-waves from the detected cardiac activity, and determining a detected paced cardiac event to be a paced right ventricle event if the detected paced cardiac event occurs close in time to a detected R wave.

17. The method of claim 15, wherein distinguishing between paced cardiac activity and non-paced cardiac activity includes generating a first detection signal for a detected positive pulse when a rising edge of a pace pulse in the sensed cardiac activity is more positive than a positive threshold, and generating a second detection signal for a detected negative pulse when a falling edge of the pace pulse in the sensed cardiac activity is more negative than a negative threshold.

18. The method of claim 17, wherein distinguishing between paced cardiac activity and non-paced cardiac activity includes:

detecting the positive pulse, and initializing a first timer, a second timer and a third timer;

searching for the negative pulse between an expiration of the first timer and an expiration of the second timer; and

upon detecting the negative pulse, waiting for an expiration of the third timer.

19. The method of claim 15, further comprising:

using the pace detector, detecting overdrive pacing, and

interrupting or modifying the neural stimulation therapy in response to the detected overdrive pacing.

20. The method of claim 19, wherein detecting antitachycardia pacing includes:

initiating a first timer, wherein the first timer is approximately 5 seconds;

detecting a first pace after the first timer expired;

initiating a second timer when the first pace is detected, wherein the second timer is approximately 330 ms;

detecting a second pace before the second timer expired, incrementing a count in response to the detected second pace, reinitiating the second timer in expectation for a subsequent pace, and comparing the count to a threshold for declaring overdrive pacing; and

detecting the subsequent pace before the reinitiated second timer expires, incrementing the count in response to the detected subsequent pace, and comparing the count to a threshold for declaring overdrive pacing.

21. The method of claim 15, further comprising determining a location of paced activity using an ECG component or a width of a detected pace pulse.