Far-field P-wave sensing in near real-time for timing delivery of pacing therapy in a cardiac medical device and medical device system

• US 10,342,981 B2
• Filed: 12/29/2017
• Issued: 07/09/2019
• Est. Priority Date: 10/29/2015
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Ghosh, Subham, Gupta, Kushagr
• Primary Examiner(s): Lavert, Nicole F
• Application Number:
  US15/858,017
• Publication Number:
  US 20180140846A1
• Time in Patent Office: 557 Days
• Field of Search: 607 4, 607 17
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/36507 controlled by gradient or slope of the heart potential
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

A medical device system for controlling ventricular pacing therapy during cardiac resynchronization therapy that includes a sensing device to sense a cardiac signal and emit a trigger signal in response to the sensed cardiac signal, a therapy delivery device to deliver the ventricular pacing in response to the emitted trigger signal, and a processor configured to identify a fiducial point of the cardiac signal sensed in real-time, set a window comprising a start point positioned a first distance prior to the fiducial point and an endpoint positioned a second distance less than the first distance subsequent to the fiducial point, determine a signal characteristic of the cardiac signal within the window, determine whether a P-wave is detected in response to the signal characteristic, determine whether an atrio-ventricular interval timer has expired, and emit a trigger signal to deliver the ventricular pacing timed off of the local maximum in response to the P-wave being detected and not timed off of the local maximum in response to the timer being expired.

Claims

1. A method for controlling delivery of a ventricular pacing therapy during atrial-synchronous ventricular pacing therapy in a medical device system, comprising:

sensing a far-field cardiac signal at a first device;

determining whether a P-wave is detected in response to the cardiac signal; and

emitting a trigger signal to a second device to deliver ventricular pacing timed off of a local maximum in response to the P-wave being detected and not timed off of the local maximum in response to a timer associated with an atrio-ventricular interval being expired.

2. The method of claim 1, further comprising:

identifying a fiducial point of the cardiac signal sensed in real-time; and

setting a window of time comprising a start point positioned a first time interval prior to the fiducial point and an endpoint positioned a second time interval subsequent to the fiducial point, the second interval being less than the first interval,

wherein determining whether the P-wave is detected is based on the cardiac signal in the window.

3. The method of claim 2, wherein at least one of the first time interval is in a range from 50 to 120 ms and the second time interval is in a range from 40 to 80 ms.

4. The method of claim 1, further comprising:

determining a change in slope of the cardiac signal;

determining the local maximum of the cardiac signal in response to the change in slope; and

using the local maximum as a fiducial point.

5. The method of claim 1, further comprising:

determining a peak-to-peak slope of the cardiac signal within a window;

determining whether a peak-to-peak slope is within a slope threshold;

determining the P-wave is detected in response to the peak-to-peak slope being within the slope threshold; and

determining whether the timer has expired in response to the peak-to-peak slope not being within the slope threshold.

6. The method of claim 1, further comprising:

determining a peak-to-peak amplitude and a peak-to-peak slope of the cardiac signal within a window;

determining whether the peak-to-peak amplitude is greater than a noise threshold;

determining whether the peak-to-peak amplitude is greater than an amplitude threshold;

determining whether the peak-to-peak slope is within a slope threshold;

determining the P-wave is detected in response to the peak-to-peak amplitude being greater than the noise threshold, the peak-to-peak amplitude not being greater than the amplitude threshold, and the peak-to-peak slope being within the slope threshold; and

determining whether the timer has expired in response to one of the peak-to-peak amplitude not being greater than the noise threshold, the peak-to-peak amplitude being greater than the amplitude threshold, and the peak-to-peak slope not being within the slope threshold.

7. The method of claim 6, further comprising:

determining a change in slope of the cardiac signal;

determining the local maximum of the cardiac signal in response to the change in slope; and

using the local maximum as a fiducial point.

8. A method for controlling delivery of a ventricular pacing therapy during atrial-synchronous ventricular pacing therapy in a medical device system, comprising:

identifying a fiducial point of a cardiac signal sensed by a first device in real-time after delivering ventricular pacing;

setting a window in time comprising a start point positioned a first time interval prior to the fiducial point and an endpoint positioned a second time interval subsequent to the fiducial point, the second interval being less than the first interval;

determining whether a P-wave is detected in response to the cardiac signal in the window; and

emitting a trigger signal to a second device to instruct delivery of ventricular pacing timed off of a local maximum in response to the P-wave being detected.

9. The method of claim 8, further comprising emitting the trigger signal to instruct delivery of ventricular pacing not timed off of the local maximum of the cardiac signal in response to a timer associated with an atrio-ventricular interval being expired.

10. The method of claim 8, further comprising:

determining a change in slope of the cardiac signal;

determining the local maximum of the cardiac signal in response to the change in slope; and

using the local maximum as the fiducial point.

11. The method of claim 8, further comprising:

determining a peak-to-peak amplitude of the cardiac signal within the window;

determining whether the peak-to-peak amplitude is within a slope threshold;

determining the P-wave is detected in response to the peak-to-peak slope being within the slope threshold; and

determining whether a timer associated with an atrio-ventricular interval has expired in response to the peak-to-peak slope not being within the slope threshold.

12. The method of claim 8, further comprising:

determining a peak-to-peak amplitude and a peak-to-peak slope of the cardiac signal within the window;

determining whether the peak-to-peak amplitude is greater than a noise threshold;

determining whether the peak-to-peak amplitude is greater than an amplitude threshold;

determining whether the peak-to-peak slope is within a slope threshold;

determining the P-wave is detected in response to the peak-to-peak amplitude being greater than the noise threshold, the peak-to-peak amplitude not being greater than the amplitude threshold, and the peak-to-peak slope being within the slope threshold; and

determining whether a timer associated with an atrio-ventricular interval has expired in response to one of the peak-to-peak amplitude not being greater than the noise threshold, the peak-to-peak amplitude being greater than the amplitude threshold, and the peak-to-peak slope not being within the slope threshold.

13. The method of claim 12, further comprising:

determining a change in slope of the cardiac signal;

determining the local maximum of the cardiac signal in response to the change in slope; and

using the local maximum as the fiducial point.

14. The method of claim 8, wherein at least one of the first time interval is in a range from 50 to 120 ms and the second time interval is in a range from 40 to 80 ms.

15. A method for controlling delivery of a ventricular pacing therapy during atrial-synchronous ventricular pacing therapy in a medical device system, comprising:

sensing a cardiac signal and emitting a trigger signal in response to the sensed cardiac signal;

delivering ventricular pacing to the patient in response to the emitted trigger signal;

identifying a fiducial point of the cardiac signal sensed in real-time;

setting a window in time comprising a start point positioned a first time interval prior to the fiducial point and an endpoint positioned a second time interval subsequent to the fiducial point, the second interval being less than the first interval;

determining a signal characteristic of the cardiac signal within the window;

determining whether a P-wave is detected in response to the signal characteristic;

determining whether a timer associated with an atrio-ventricular interval has expired; and

emitting the trigger signal to instruct delivery of ventricular pacing timed off of a local maximum in response to the P-wave being detected and not timed off of the local maximum in response to the timer being expired.

16. The method of claim 15, further comprising:

determining a change in slope of the cardiac signal;

determining the local maximum of the cardiac signal in response to the change in slope; and

using the local maximum as the fiducial point.

17. The method of claim 15, further comprising:

determining a peak-to-peak slope of the cardiac signal within the window;

determining whether the peak-to-peak slope is within a slope threshold;

determining the P-wave is detected in response to the peak-to-peak slope being within the slope threshold; and

determining whether the timer has expired in response to the peak-to-peak slope not being within the slope threshold.

18. The method of claim 15, further comprising:

determining a peak-to-peak amplitude and a peak-to-peak slope of the cardiac signal within the window;

determining whether the peak-to-peak amplitude is greater than a noise threshold;

determining whether the peak-to-peak amplitude is greater than an amplitude threshold;

determining whether the peak-to-peak slope is within a slope threshold;

determining the P-wave is detected in response to the peak-to-peak amplitude being greater than the noise threshold, the peak-to-peak amplitude not being greater than the amplitude threshold, and the peak-to-peak slope being within the slope threshold; and

determining whether the timer has expired in response to one of the peak-to-peak amplitude not being greater than the noise threshold, the peak-to-peak amplitude being greater than the amplitude threshold, and the peak-to-peak slope not being within the slope threshold.

19. The method of claim 18, further comprising:

determining a change in slope of the cardiac signal;

determining the local maximum of the cardiac signal in response to the change in slope; and

using the local maximum as the fiducial point.

20. The method of claim 15, wherein at least one of the first time interval is in a range from 50 to 120 ms and the second time interval is in a range from 40 to 80 ms.