ATRIAL CONTRACTION DETECTION BY A VENTRICULAR LEADLESS PACING DEVICE FOR ATRIO-SYNCHRONOUS VENTRICULAR PACING

• US 20160023000A1
• Filed: 12/22/2014
• Published: 01/28/2016
• Est. Priority Date: 07/25/2014
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: SAMBELASHVILI, Aleksandre T., SHELDON, Todd J., CHO, Yong K.
• Granted Patent: US 9,399,140 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/06 for high-frequency therapy
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/36578 controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators

Abstract

A leadless pacing device (LPD) includes a motion sensor configured to generate a motion signal as a function of heart movement. The LPD is configured to analyze the motion signal within an atrial contraction detection window that begins an atrial contraction detection delay period after activation of the ventricle, and detect a contraction of an atrium of the heart based on the analysis of the motion signal within the atrial contraction detection window. If the LPD does not detect a ventricular depolarization subsequent to the atrial contraction, e.g., with an atrio-ventricular (AV) interval beginning when the atrial contraction was detected, the LPD delivers a ventricular pacing pulse.

Claims

1. A leadless pacing device configured to deliver atrio-synchronous ventricular pacing, the leadless pacing device comprising:

a plurality of electrodes;

a motion sensor configured to generate a motion signal as a function of movement of a heart of a patient;

a stimulation module coupled to the plurality of electrodes, wherein the stimulation module is configured to generate pacing pulses and deliver the pacing pulses to a ventricle of the heart via the plurality of electrodes;

an electrical sensing module coupled to the plurality of electrodes, wherein the electrical sensing module is configured to detect depolarizations of the ventricle within a cardiac electrogram sensed via the plurality of electrodes;

a mechanical sensing module coupled to the motion sensor and configured to;

receive the motion signal from the motion sensor;

identify an activation of the ventricle;

upon identification of the activation of the ventricle, initiate an atrial contraction detection delay period;

analyze the motion signal within an atrial contraction detection window that begins upon completion of the atrial contraction detection delay period; and

detect a contraction of an atrium of the heart based on the analysis of the motion signal within the atrial contraction detection window;

a processing module configured to control the stimulation module to generate a pacing pulse and deliver the pacing pulse to the ventricle via the plurality of electrodes in response to the detection of the contraction of the atrium by the mechanical sensing module; and

a housing configured to be implanted within the ventricle, wherein the housing encloses the motion sensor, the stimulation module, the electrical sensing module, the mechanical sensing module, and the processing module.

2. The leadless pacing device of claim 1, wherein, to identify the activation of the ventricle, the mechanical sensing module is configured to at least one of:

determine that the electrical sensing module detected a depolarization of the ventricle;

determine that the stimulation module generated a pacing pulse and delivered the pacing pulse to the ventricle via the plurality of electrodes;

or

detect a contraction of the ventricle based on the motion signal.

3. The leadless pacing device of claim 1, wherein the atrial contraction detection delay period is at least 400 milliseconds.

4. The leadless pacing device of claim 1, wherein the mechanical sensing module is configured to adjust the atrial contraction delay period based on a heart rate of the patient.

5. The leadless pacing device of claim 1, wherein the processing module is configured to:

determine that the electrical sensing module did not detect a depolarization of the ventricle within an atrioventricular (AV) interval beginning when the mechanical sensing module detected the contraction of the atrium; and

control the stimulation module to generate the pacing pulse and deliver the pacing pulse to the ventricle via the plurality of electrodes in response to the determination.

6. The leadless pacing device of claim 5, wherein the AV interval is less than 100 milliseconds.

7. The leadless pacing device of claim 5, wherein the AV interval is less than 50 milliseconds.

8. The leadless pacing device of claim 5, wherein the AV interval is approximately 30 milliseconds.

9. The leadless pacing device of claim 5, wherein the mechanical sensing module is configured to detect a contraction of the ventricle based on the motion signal after delivery of the pacing pulse to the ventricle, and the processing module is configured to:

determine whether the delivery of the pacing pulse to the ventricle was effective based on the detection of the contraction of the ventricle; and

adjust the AV interval based on the determination of whether the delivery of the pacing pulse to the ventricle was effective.

10. The leadless pacing device of claim 9, wherein the processing module is configured to:

determine that an interval from the delivery of the pacing pulse to the detection of the contraction of the ventricle is less than a threshold; and

decrease the AV interval in response to the determination that the interval from the delivery of the pacing pulse to the detection of the contraction of the ventricle is less than the threshold.

11. The leadless pacing device of claim 9,

wherein the mechanical sensing module is configured to:

detect a peak of the ventricular contraction based on the motion signal; and

determine an amplitude of the motion signal at the peak, and wherein the processing module is configured to;

determine that the amplitude is greater than the threshold; and

increase the AV interval in response to the determination that the amplitude is greater than the threshold.

12. The leadless pacing device of claim 5,

wherein the AV interval comprises a mechanical AV interval,

wherein the electrical sensing module is configured to detect depolarizations of the atrium within the cardiac electrogram sensed via the plurality of electrodes,

wherein, in response to the electrical sensing module detecting a depolarization of the atrium, the processing module is configured to:

determine that the electrical sensing module did not detect a depolarization of the ventricle within an electrical AV interval beginning when the electrical sensing module detected the depolarization of the atrium; and

control the stimulation module to generate a pacing pulse and deliver the pacing pulse to the ventricle via the plurality of electrodes in response to the determination that the electrical sensing module did not detect a depolarization of the ventricle,

wherein the processing module is further configured to determine that the electrical sensing module did not detect a depolarization of the atrium during a predetermined number of one or more cardiac cycles and, in response to the determination;

control the mechanical sensing module to detect a contraction of the atrium based on the motion signal;

determine that the electrical sensing module did not detect a depolarization of the ventricle within the mechanical AV interval beginning when the mechanical sensing module detected the contraction of the atrium; and

control the stimulation module to generate a pacing pulse and deliver the pacing pulse to the ventricle via the plurality of electrodes in response to the determination that the mechanical sensing module did not detect a depolarization of the ventricle, and

wherein the electrical AV interval is greater than the mechanical AV interval.

13. The leadless pacing device of claim 1, wherein the mechanical sensing module is configured to determine an amount of motion of the patient based on the motion signal, and the processing module is configured to control the stimulation module to generate pacing pulses and deliver the pacing pulses to the ventricle according to an asynchronous ventricular pacing mode in response to the amount of motion of the patient exceeding a threshold.

14. The leadless pacing device of claim 1, wherein the processing module is configured to:

determine that the mechanical sensing module did not detect a contraction of the atrium during a predetermined number of one or more cardiac cycles; and

control the stimulation module to generate pacing pulses and deliver the pacing pulses to the ventricle according to an asynchronous ventricular pacing mode in response to the determination.

15. The leadless pacing device of claim 1, wherein the processing module is configured to:

determine a heart rate of the patient based on depolarizations detected by the electrical sensing module;

determine that the heart rate exceeds a threshold; and

control the stimulation module to generate pacing pulses and deliver the pacing pulses to the ventricle according to an asynchronous ventricular pacing mode in response to the determination that the heart rate exceeds the threshold.

16. The leadless pacing device of claim 1,

wherein the motion sensor comprises a plurality of accelerometers, each of the plurality of accelerometers oriented along a respective axis and configured to generate a respective accelerometer signal,

wherein mechanical sensing module derives the motion signal based on a first one or more of the accelerometer signals according to a first sensing vector, and wherein the processing module is configured to:

determine that the mechanical sensing module did not detect a contraction of the atrium during a predetermined number of one or more cardiac cycles; and

control the mechanical sensing module to derive the motion signal based on a second one or more of the accelerometer signals according to a second sensing vector in response to the determination.

17. A method for delivering atrio-synchronous ventricular pacing by a leadless pacing device implanted within a ventricle of a heart of a patient, the method comprising:

identifying an activation of the ventricle;

upon identification of the activation of the ventricle, initiating an atrial contraction detection delay period;

analyzing a motion signal within an atrial contraction detection window that begins upon completion of the atrial contraction detection delay period, wherein the motion signal is generated by a motion sensor of the leadless pacing device as a function of movement of the heart;

detecting a contraction of an atrium of the heart based on the analysis of the motion signal within the atrial contraction detection window; and

delivering a pacing pulse to the ventricle in response to the detection of the atrial contraction.

18. The method of claim 17, further comprising adjusting the atrial contraction delay period based on a heart rate of the patient.

19. The method of claim 17, further comprising:

determining that a depolarization of the ventricle resulting from the depolarization of the atrium that caused the contraction of the atrium was not detected within an atrioventricular (AV) interval beginning when the contraction of the atrium was detected; and

delivering the pacing pulse to the ventricle in response to the determination.

20. The method of claim 19, further comprising:

detecting a contraction of the ventricle based on the motion signal after delivery of the pacing pulse to the ventricle;

determining whether the delivery of the pacing pulse to the ventricle was effective based on the detection of the contraction of the ventricle; and

adjusting the AV interval based on the determination of whether the delivery of the pacing pulse to the ventricle was effective.

21. The method of claim 20, further comprising:

determining that an interval from the delivery of the pacing pulse to the detection of the contraction of the ventricle is less than a threshold; and

decreasing the AV interval in response to the determination that the interval from the delivery of the pacing pulse to the detection of the contraction of the ventricle is less than the threshold.

22. The method of claim 20, further comprising:

detecting a peak of the ventricular contraction based on the motion signal;

determining an amplitude of the motion signal at the peak;

determining that the amplitude is greater than the threshold; and

increasing the AV interval in response to the determination that the amplitude is greater than the threshold.

23. The method of claim 19, wherein the leadless pacing device is configured to detect depolarizations of the atrium, and the AV interval comprises a mechanical AV interval, the method further comprising:

in response to detecting a depolarization of the atrium;

determining that a depolarization of the ventricle was not detected within an electrical AV interval beginning when the electrical sensing module detected the depolarization of the atrium; and

delivering a pacing pulse to the ventricle in response to the determination that a depolarization of the ventricle was not detected, and in response to determining that a depolarization of the atrium was not detected during a predetermined number of one or more cardiac cycles;

detecting a contraction of the atrium based on the motion signal;

determining that a depolarization of the ventricle was not detected within the mechanical AV interval beginning when the contraction of the atrium was detected; and

delivering a pacing pulse to the ventricle in response to the determination that a depolarization of the ventricle was not detected, and wherein the electrical AV interval is greater than the mechanical AV interval.

24. The method of claim 17, further comprising:

determining an amount of motion of the patient based on the motion signal; and

delivering the pacing pulses to the ventricle according to an asynchronous ventricular pacing mode in response to the amount of motion of the patient exceeding a threshold.

25. The method of claim 17, further comprising:

determining a contraction of the atrium was not detected during a predetermined number of one or more cardiac cycles; and

delivering pacing pulses to the ventricle according to an asynchronous ventricular pacing mode in response to the determination.

26. The method of claim 17, further comprising:

determining that a heart rate exceeds a threshold; and

delivering the pacing pulses to the ventricle according to an asynchronous ventricular pacing mode in response to the determination that the heart rate exceeds the threshold.

27. A leadless pacing device configured to deliver atrio-synchronous ventricular pacing, the leadless pacing device comprising:

means for generating a motion signal as a function of movement of a heart of a patient;

means for identifying an activation of a ventricle of the heart;

means for initiating an atrial contraction detection delay period upon identification of the activation of the ventricle;

means for analyzing the motion signal within an atrial contraction detection window that begins upon completion of the atrial contraction detection delay period;

means for detecting a contraction of an atrium of the heart based on the analysis of the motion signal within the atrial contraction detection window; and

means for delivering a pacing pulse to the ventricle in response to the detection of the atrial contraction.

28. A computer-readable storage medium comprising instructions stored thereon that, when executed by one or more programmable processors of a leadless pacing device configured to deliver atrio-synchronous ventricular pacing, cause the one or more processors to:

identify an activation of the ventricle;

upon identification of the activation of the ventricle, initiate an atrial contraction detection delay period;

analyze a motion signal within an atrial contraction detection window that begins upon completion of the atrial contraction detection delay period, wherein the motion signal is generated by a motion sensor of the leadless pacing device as a function of movement of the heart;

detect a contraction of an atrium of the heart based on the analysis of the motion signal within the atrial contraction detection window; and

control delivery of a pacing pulse to the ventricle in response to the detection of the contraction of the atrium.