FAR-FIELD R-WAVE DETECTION TO CONTROL ATRIAL PACE TIMING IN A DUAL-CHAMBER LEADLESS PACEMAKER

• US 20160067486A1
• Filed: 10/09/2014
• Published: 03/10/2016
• Est. Priority Date: 09/08/2014
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Brown, Mark L., Greenhut, Saul E., Jackson, Troy E.
• Granted Patent: US 9,889,303 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• 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 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: A61N 1/371 Capture, i.e. successful stimulation
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators

Abstract

A method for sensing far-field R-waves in a leadless, intracardiac pacemaker implanted in an atrium of a patient'"'"'s heart may involve sensing an electrical signal generated by the heart with two electrodes and a first sensing channel and/or a second sensing channel of the pacemaker, comparing a first timing marker from the first sensing channel with a second timing marker from the second sensing channel, and either determining that the sensed signal is a P-wave, if the first and second timing markers indicate that the sensed signal was sensed by the first and second sensing channels within a predetermined threshold of time from one another, or determining that the sensed signal is a far-field R-wave, if the sensed signal is sensed by the second sensing channel and not sensed by the first sensing channel.

Claims

1. A method for sensing far-field R-waves in a leadless, intracardiac pacemaker implanted in an atrium of a patient'"'"'s heart, the method comprising:

sensing an electrical signal generated by the heart with two electrodes and at least one of a first sensing channel of the pacemaker or a second sensing channel of the pacemaker, wherein the first sensing channel is configured to sense P-waves and reject far-field R-waves, and wherein the second sensing channel is configured to sense both P-waves and far-field R-waves;

comparing, with a processor in the pacemaker, a first timing marker from the first sensing channel with a second timing marker from the second sensing channel; and

either;

determining, with the processor, that the sensed signal is a P-wave, if the first and second timing markers indicate that the sensed signal was sensed by the first and second sensing channels within a predetermined threshold of time from one another;

or

determining, with the processor, that the sensed signal is a far-field R-wave, if the sensed signal is sensed by the second sensing channel and not sensed by the first sensing channel.

2. The method of claim 1, further comprising repeating the sensing, comparing and determining steps for multiple electrical signals generated by the heart.

3. The method of claim 1, further comprising repeating the sensing, comparing and determining steps during multiple cardiac cycles of the heart.

4. The method of claim 3, further comprising calculating, with the processor in the pacemaker, a moving average of far-field R-wave intervals.

5. The method of claim 4, further comprising delivering a pacing therapy by the pacemaker to the atrium of the heart, based at least in part on the moving average.

6. The method of claim 1, wherein the method is performed using a system comprising the pacemaker in the atrium and at least one additional leadless pacemaker implanted in a ventricle of the heart.

7. The method of claim 1, wherein a first band-pass filter of the first sensing channel has a frequency range with a low end of approximately 10 Hz to approximately 40 Hz and a high end of greater than approximately 30 Hz and a low sensitivity threshold of about 1 mV, and wherein a second band-pass filter of the second sensing channel has a frequency range with a low end of approximately 0.5 Hz to approximately 20 Hz and a high end of greater than approximately 20 Hz and a high sensitivity threshold of about 0.15 mV.

8. The method of claim 1, wherein the predetermined threshold of time is about 50 milliseconds.

9. The method of claim 1, further comprising setting a blanking period after sensing the electrical signal, to prevent waveforms from being detected multiple times.

10. The method of claim 1, further comprising setting an atrial pace timer of the pacemaker.

11. A non-transitory, computer-readable storage medium storing a set of instructions that cause a leadless, intracardiac pacemaker implanted in an atrium of a patient'"'"'s heart to perform a method, the method comprising:

sensing an electrical signal generated by the heart with two electrodes and at least one of a first sensing channel of the pacemaker configured to sense P-waves and reject far-field R-waves or a second sensing channel of the pacemaker configured to sense both P-waves and far-field R-waves;

comparing, with a processor in the pacemaker, a first timing marker from the first sensing channel with a second timing marker from the second sensing channel; and

either;

determining, with the processor, that the sensed signal is a P-wave, if the first and second timing markers indicate that the sensed signal was sensed by the first and second sensing channels within a predetermined threshold of time from one another;

or

determining, with the processor, that the sensed signal is a far-field R-wave, if the sensed signal is sensed by the second sensing channel and not sensed by the first sensing channel.

12. The storage medium of claim 11, wherein the method further comprises repeating the sensing, comparing and determining steps for multiple electrical signals generated by the heart.

13. The storage medium of claim 11, wherein the method further comprises repeating the sensing, comparing and determining steps during multiple cardiac cycles of the heart.

14. The storage medium of claim 13, wherein the method further comprises calculating, with the processor in the pacemaker, a moving average of far-field R-wave intervals.

15. The storage medium of claim 14, wherein the method further comprises delivering a pacing therapy by the pacemaker to the atrium of the heart, based at least in part on the moving average.

16. The storage medium of claim 11, wherein the method is performed using a system comprising the pacemaker in the atrium and at least one additional leadless pacemaker implanted in a ventricle of the heart.

17. The storage medium of claim 11, wherein a first band-pass filter of the first sensing channel has a frequency range with a low end of approximately 10 Hz to approximately 40 Hz and a high end of greater than approximately 30 Hz and a low sensitivity threshold of about 1 mV, and wherein a second band-pass filter of the second sensing channel has a frequency range with a low end of approximately 0.5 Hz to approximately 20 Hz and a high end of greater than approximately 20 Hz and a high sensitivity threshold of about 0.15 mV.

18. The storage medium of claim 11, wherein the predetermined threshold of time is about 50 milliseconds.

19. The storage medium of claim 11, wherein the method further comprises setting a blanking period after sensing the electrical signal, to prevent waveforms from being detected multiple times.

20. The storage medium of claim 11, wherein the method further comprises setting an atrial pace timer of the pacemaker.

21. An implantable leadless pacemaker device, comprising:

a housing;

at least one attachment member on the housing for attaching the pacemaker device to an inner wall of a heart;

a first electrode;

a second electrode;

a first sensing channel in the housing, configured to sense P-waves and having a first band-pass filter with a frequency range of approximately with a low end of approximately 10 Hz to approximately 40 Hz and a high end of greater than approximately 30 Hz and a low sensitivity threshold of about 1 mV;

a second sensing channel in the housing, configured to sense far-field R-waves and P-waves and having a second band-pass filter with a frequency range with a low end of approximately 0.5 Hz to approximately 20 Hz and a high end of greater than approximately 20 Hz and a high sensitivity threshold of about 0.15 mV; and

a processor configured to distinguish between P-waves and far-field R-waves based on data from the sensing channels and to generate a timing signal for timing atrial pacing therapy delivered by the pacemaker.

22. The device of claim 21, wherein the first and second electrodes are spaced at least 17 millimeters apart.

23. The device of claim 21, further comprising an analog-to-digital converter configured to convert analog signals detected by the electrodes into digital signals for processing by the sensing channels.

24. The device of claim 21, wherein the sensing channels are located within the processor.

25. An intracardiac pacemaker system, comprising:

an implantable, leadless, atrial pacemaker device, comprising;

a housing;

at least one attachment member on the housing for attaching the pacemaker device to an inner wall of a heart;

a first electrode;

a second electrode;

a first sensing channel in the housing, configured to sense P-waves and having a first band-pass filter with a frequency range with a low end of approximately 10 Hz to approximately 40 Hz and a high end of greater than approximately 30 Hz and a low sensitivity threshold of about 1 mV;

a second sensing channel in the housing, configured to sense far-field R-waves and P-waves and having a second band-pass filter with a frequency range with a low end of approximately 0.5 Hz to approximately 20 Hz and a high end of greater than approximately 20 Hz and a high sensitivity threshold of about 0.15 mV; and

a processor configured to distinguish between P-waves and far-field R-waves based on data from the sensing channels and to generate a timing signal for timing atrial pacing therapy delivered by the pacemaker; and

an implantable, leadless, ventricular pacemaker device.

26. The system of claim 25, wherein the first and second electrodes are spaced at least 17 millimeters apart.

27. The system of claim 25, further comprising an analog-to-digital converter configured to convert analog signals detected by the electrodes into digital signals for processing by the sensing channels.

28. The system of claim 25, wherein the sensing channels are located within the processor.

29. An implantable leadless pacemaker device, comprising:

a housing;

at least one attachment member on the housing for attaching the pacemaker device to an inner wall of a heart;

a first electrode;

a second electrode; and

a processor configured to process data sensed by the electrodes and converted to digital data to distinguish between P-waves and far-field R-waves, wherein the processor comprises;

a first sensing channel, configured to sense P-waves and having a first band-pass filter with a frequency range with a low end of approximately 10 Hz to approximately 40 Hz and a high end of greater than approximately 30 Hz and a low sensitivity threshold of about 1 mV; and

a second sensing channel, configured to sense far-field R-waves and P-waves and having a second band-pass filter with a frequency range with a low end of approximately 0.5 Hz to approximately 20 Hz and a high end of greater than approximately 20 Hz and a high sensitivity threshold of about 0.15 mV.