SYSTEM AND METHOD FOR DUAL-CHAMBER PACING

• US 20160067487A1
• Filed: 12/22/2014
• 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: DEMMER, Wade M., GREENHUT, Saul E., SHELDON, Todd J., KLECKNER, Karen J., CARNEY, James K., ANDERSON, David A.
• Granted Patent: US 9,399,139 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/0573 chacterised by means penetrating the heart tissue, e.g. helix needle or hook
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• 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 1/36528 the parameter being measured by means of ultrasound
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• 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 1/36592 controlled by the heart rate variability
• 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 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/3688 configured for switching the pacing mode, e.g. from AAI to DDD
• 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 medical device system including an pacemaker implantable in a chamber of a patient'"'"'s heart is configured to sense near field events from a cardiac electrical signal, establish a lower rate interval to control a rate of delivery of pacing pulses and schedule a first pacing pulse by starting a pacing escape interval set equal to the lower rate interval. The pacemaker withholds the scheduled pacing pulse in response to sensing a near-field event during the pacing escape interval and schedules a next pacing pulse to be delivered at the lower rate interval from a time that the pacing escape interval is scheduled to expire.

Claims

1. An implantable cardiac pacing system, comprising:

a first pacemaker implantable in a first chamber of a heart of a patient and comprising;

a first sensing module configured to receive a cardiac electrical signal and sense near field events in the first chamber from the cardiac electrical signal,

a first pulse generator configured to generate and deliver pacing pulses to the first chamber via a pair of electrodes, and

a first control module coupled to the first sensing module and the first pulse generator and configured to;

establish a lower rate interval to control a rate of delivery of the pacing pulses,

schedule a first pacing pulse to be delivered by the first pulse generator by starting a first pacing escape interval equal to the lower rate interval,

withhold the scheduled pacing pulse in response to the first sensing module sensing a near-field event during the first pacing escape interval, and

schedule a next pacing pulse to be delivered at the lower rate interval from a time that the first pacing escape interval is scheduled to expire.

2. The system of claim 1, wherein the first control module is configured to schedule the next pacing pulse by:

starting a second pacing escape interval at a time that the near-field event is sensed by the sensing module during the first pacing escape interval, the second pacing escape interval comprising a sum of the lower rate interval and an unexpired portion of the first pacing escape interval at the time that the near-field event is sensed during the first pacing escape interval.

3. The system of claim 1, wherein the first control module is configured to schedule the next pacing pulse by:

allowing the first pacing escape interval to expire; and

starting a second pacing escape interval equal to the lower rate interval upon expiration of the first pacing escape interval.

4. The system of claim 3, wherein the first control module is further configured to:

withhold the next pacing pulse at an expiration of the second pacing escape interval in response to the first sensing module sensing a near-field event during the second pacing escape interval;

start a third pacing escape interval equal to the lower rate interval upon expiration of the second pacing interval.

5. The system of claim 1, wherein:

the first sensing module is further configured to sense far field events, the far-field event occurring in a second chamber of the heart different than the first chamber;

the first control module further configured to schedule the next pacing pulse by starting a second pacing escape interval equal to the lower rate interval less a target inter-chamber interval in response to the first sensing module sensing a far field event during the first escape interval.

6. The system of claim 5, wherein the first control module is further configured to:

withhold the next pacing pulse scheduled to be delivered at an expiration of the second pacing escape interval in response to the first sensing module sensing a near-field event at a time during the second pacing escape interval; and

schedule a third pacing pulse to be delivered to the first chamber at the lower rate interval from the expiration of the second pacing escape interval.

7. The system of claim 6 wherein the first control module is configured to schedule the third pacing pulse by:

starting a third pacing escape interval in response to the first sensing module sensing the near-field event at a time during the second pacing escape interval, the third pacing escape interval comprising a sum of the lower rate interval and an unexpired time of the second pacing escape interval remaining at the time that the near-field event was sensed during the second pacing escape interval.

8. The system of claim 6 wherein the first control module is configured to schedule the third pacing pulse by:

allowing the second pacing escape interval to expire; and

starting a third pacing escape interval equal to the lower rate interval upon expiration of the second pacing escape interval.

9. The system of claim 5, wherein the first control module is further configured to:

determine a time interval from a preceding event in the first chamber to the sensed far-field event;

compare the determined time interval to a time limit;

start the second pacing escape interval only if the determined time interval is within the time limit.

10. The system of claim 9, wherein the first control module is further configured to:

allow the first pacing escape interval to expire in response to the determined time interval being outside the time limit;

withhold the first scheduled pacing pulse upon expiration of the first pacing escape interval; and

start a third pacing escape interval equal to the lower rate interval upon expiration of the first pacing escape interval.

11. The system of claim 5, wherein the first control module is further configured to:

allow the second pacing escape interval to expire in response to the sensing module sensing a next far-field event during the second pacing escape interval;

withhold a pacing pulse scheduled to occur at the expiration of the second pacing escape interval; and

start a third pacing escape interval equal to the lower rate interval at the expiration of the second pacing escape interval.

12. The system of claim 5, further comprising an acoustical sensor configured to produce a signal comprising heart sounds signals;

the first sensing module configured to sense the far field ventricular events from the acoustical sensor signal.

13. The system of claim 1, further comprising:

a second pacemaker implantable in a second chamber of the heart of the patient and comprising;

a second sensing module configured to receive a second cardiac electrical signal and sense second chamber near field events from the second cardiac electrical signal, the second chamber near field events occurring in the second chamber,

a second pulse generator configured to generate and deliver pacing pulses to the second chamber via a second pair of electrodes, and

a second control module configured to;

establish a second lower rate interval for controlling a rate of the pacing pulses delivered to the second chamber;

set a second chamber pacing escape interval to a test interval longer than the second lower rate interval in response to the second sensing module sensing a second chamber near-field event during at least one second lower rate interval;

set the second chamber pacing escape interval to a back-up pacing interval longer than the second lower rate interval in response to the second sensing module sensing a second chamber near-field event during the test interval, and

set the second chamber pacing escape interval equal to the second lower rate interval in response to at least one back-up pacing interval expiring without the second sensing module sensing a second chamber near-field event during the at least one back-up pacing interval.

14. The system of claim 1, wherein the first intracardiac pacemaker comprises a housing enclosing the first sensing module, the first pulse generator, and the first control module, the pair of electrodes carried by the housing.

15. A method, comprising:

sensing near field events in a first chamber of a patient'"'"'s heart from a cardiac electrical signal received by a first sensing module of a first pacemaker implantable in the first chamber;

establishing by the first pacemaker a lower rate interval to control a rate of delivery of pacing pulses;

scheduling a first pacing pulse by starting a first pacing escape interval set equal to the lower rate interval;

withholding the scheduled pacing pulse in response to sensing a near-field event during the first pacing escape interval; and

scheduling a next pacing pulse to be delivered at the lower rate interval from a time that the first pacing escape interval is scheduled to expire.

16. The method of claim 15, further comprising:

starting a second pacing escape interval at a time that the near-field event is sensed by the sensing module during the first pacing escape interval, the second pacing escape interval comprising a sum of the lower rate interval and an unexpired portion of the first pacing escape interval at the time that the near-field event is sensed during the first pacing escape interval.

17. The method of claim 15, wherein scheduling the next pacing pulse comprises:

allowing the first pacing escape interval to expire; and

starting a second pacing escape interval equal to the lower rate interval upon expiration of the first pacing escape interval.

18. The method of claim 17, further comprising:

withholding the next pacing pulse at an expiration of the second pacing escape interval in response to the first sensing module sensing a near-field event during the second pacing escape interval;

starting a third pacing escape interval equal to the lower rate interval upon expiration of the second pacing interval.

19. The method of claim 15, further comprising:

sensing far field events by the first pacemaker, the far field events occurring in a second chamber of the heart different than the first chamber;

scheduling the next pacing pulse by starting a second pacing escape interval equal to the lower rate interval less a target inter-chamber interval in response to the first sensing module sensing a far field event during the first escape interval.

20. The method of claim 19, further comprising:

withholding the next pacing pulse scheduled to be delivered at an expiration of the second pacing escape interval in response to sensing a near-field event at a time during the second pacing escape interval; and

scheduling a third pacing pulse to be delivered to the first chamber at the lower rate interval from the expiration of the second pacing escape interval.

21. The method of claim 20, wherein scheduling the third pacing pulse comprises:

starting a third pacing escape interval in response to sensing the near-field event at a time during the second pacing escape interval, the third pacing escape interval comprising a sum of the lower rate interval and an unexpired time of the second pacing escape interval remaining at the time that the near-field event was sensed during the second pacing escape interval.

22. The method of claim 20, wherein scheduling the third pacing pulse comprises:

allowing the second pacing escape interval to expire; and

starting a third pacing escape interval equal to the lower rate interval upon expiration of the second pacing escape interval.

23. The method of claim 19, further comprising:

determining a time interval from a preceding event in the first chamber to the sensed far-field event;

comparing the determined time interval to a time limit;

starting the second pacing escape interval only if the determined time interval is within the time limit.

24. The method of claim 23, further comprising:

allowing the first pacing escape interval to expire in response to the determined time interval being outside the time limit;

withholding the first scheduled pacing pulse upon expiration of the first pacing escape interval; and

starting a third pacing escape interval equal to the lower rate interval upon expiration of the first pacing escape interval.

25. The method of claim 19, further comprising:

allowing the second pacing escape interval to expire in response to the sensing module sensing a next far-field event during the second pacing escape interval;

withholding a pacing pulse scheduled to occur at the expiration of the second pacing escape interval; and

starting a third pacing escape interval equal to the lower rate interval at the expiration of the second pacing escape interval.

26. The method of claim 15, further comprising:

sensing second chamber near field events by a second sensing module of a second pacemaker implantable in a second chamber of the patient'"'"'s heart different than the first chamber, the second chamber near field events occurring in the second chamber,

establishing by the second pacemaker a second lower rate interval for controlling a rate of the pacing pulses delivered to the second chamber;

setting by the second pacemaker a second chamber pacing escape interval to a test interval longer than the second lower rate interval in response to the second sensing module sensing a second chamber near-field event during at least one second lower rate interval;

setting the second chamber pacing escape interval to a back-up pacing interval longer than the second lower rate interval in response to the second sensing module sensing a second chamber near-field event during the test interval, and

setting the second chamber pacing escape interval equal to the second lower rate interval in response to at least one back-up pacing interval expiring without the second sensing module sensing a second chamber near-field event during the at least one back-up pacing interval.

27. The method of claim 19, further comprising sensing the far field ventricular events from an acoustical sensor signal.

28. A non-transitory, computer-readable medium comprising a set of instructions which, when executed by a control module of a pacemaker implantable in a chamber of a patient'"'"'s heart, cause the pacemaker to:

sense near field events from a cardiac electrical signal;

establish a lower rate interval to control a rate of delivery of pacing pulses;

schedule a first pacing pulse by starting a pacing escape interval set equal to the lower rate interval;

withholding the scheduled pacing pulse in response to sensing a near-field event during the pacing escape interval; and

scheduling a next pacing pulse to be delivered at the lower rate interval from a time that the pacing escape interval is scheduled to expire.