CARDIAC PACING WITH GOVERNOR

• US 20170056668A1
• Filed: 08/23/2016
• Published: 03/02/2017
• Est. Priority Date: 08/24/2015
• Status: Abandoned Application

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Maile, Keith R., Kane, Michael J., Linder, William J.
• Application Number:
  US15/244,694
• Publication Number:
  US 20170056668A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6869 Heart
• 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 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators

Abstract

A leadless cardiac pacemaker includes a housing and two or more electrodes secured relative to the housing. A controller is configured to receive electrical signals from the two or more electrodes indicative of a heartbeat of the patient'"'"'s heart and determine a first measure of cardiac load based at least in part on a delay between the Q or R feature and the T feature for the heartbeat. An accelerometer is configured to sense an activity level of the patient and the controller is configured to determine a second measure of cardiac load based at least in part on the activity level of the patient. A pacing rate is based at least in part upon the first measure of cardiac load, with the second measure of cardiac load used as a governor to the determined pacing rate.

Claims

1. A leadless cardiac pacemaker (LCP) configured to sense and pace a patient'"'"'s heart, the LCP comprising:

a housing;

two or more electrodes secured relative to the housing and configured to receive electrical signals emanating from the patient'"'"'s heart;

a controller coupled to the two or more electrodes, the controller configured to receive electrical signals from the two or more electrodes indicative of a heartbeat of the patient'"'"'s heart, the received electrical signals including one or more of a Q, an R, and an S feature, as well as a T feature of a QRST complex, the controller configured to determine a first measure of cardiac load based at least in part on a delay between the Q or R feature and the T feature for the heart beat;

an accelerometer configured to sense an activity level of the patient, the controller configured to determine a second measure of cardiac load based at least in part on the activity level of the patient;

the controller further configured to determine a pacing rate based at least in part upon the first measure of cardiac load and to pace the patient'"'"'s heart in accordance with the determined pacing rate; and

the controller further configured to utilize the second measure of cardiac load to act as a governor to the determined pacing rate.

2. The LCP of claim 1, wherein the controller is configured to determine the first measure of cardiac load based at least in part on a delay between the R feature and the T feature for the heartbeat.

3. The LCP of claim 1, wherein the controller is configured to receive electrical signals from the two or more electrodes indicative of a plurality of heartbeats, and the controller is configured to determine the first measure of cardiac load based at least in part on a delay between the Q or R feature and the T feature of each of two or more heartbeats.

4. The LCP of claim 1, wherein the controller is configured to:

repeatedly activate and deactivate the accelerometer to intermittently sense the activity level of the patient; and

determine the second measure of cardiac load based at least in part on two or more intermittently sensed activity levels of the patient.

5. The LCP of claim 1, wherein the controller is configured to act as a governor by determining a pacing rate limit based at least in part on the second measure of cardiac load, and to limit the determined pacing rate based on the pacing rate limit.

6. The LCP of claim 5, wherein the pacing rate limit is a function of the second measure of cardiac load, and the function is not a constant function.

7. The LCP of claim 1, wherein the controller is configured to determine the pacing rate based at least in part upon the first measure of cardiac load using a linear function having a non-zero slope.

8. The LCP of claim 1, wherein the accelerometer is configured to sense non-cardiac movement of the patient, and the activity level of the patient is based on the sensed non-cardiac movement of the patient.

9. The LCP of claim 1, wherein the accelerometer is configured to sense cardiac movement, and the activity level of the patient is based on the sensed cardiac movement.

10. The LCP of claim 1, wherein the accelerometer is configured to sense non-cardiac movement of the patient and cardiac movement, and the activity level of the patient is based at least in part on the sensed non-cardiac movement of the patient and the sensed cardiac movement.

11. A leadless cardiac pacemaker (LCP) configured to sense and pace a patient'"'"'s heart, the LCP comprising:

a housing;

two or more electrodes secured relative to the housing and configured to receive electrical signals emanating from the patient'"'"'s heart;

a controller coupled to the two or more electrodes, the controller configured to receive electrical signals from the two or more electrodes and determine a first measure of cardiac load based on the received electrical signals;

a sensor configured to provide a second measure of cardiac load, the sensor operatively coupled to the controller;

the controller further configured to determine a pacing rate based at least in part upon the first measure of cardiac load and to pace the patient'"'"'s heart in accordance with the determined pacing rate; and

the controller further configured to use the second measure of cardiac load to determine a pacing rate limit, and to limit the determined pacing rate based on the pacing rate limit.

12. The leadless cardiac pacemaker (LCP) of claim 11, wherein the first measure of cardiac load is representative of how quickly the patient'"'"'s heart prepares for a subsequent heartbeat.

13. The leadless cardiac pacemaker (LCP) of claim 11, wherein the first measure of cardiac load is representative of a time required for ventricle depolarization and repolarization.

14. The leadless cardiac pacemaker (LCP) of claim 11, wherein the first measure of cardiac load comprises a RT interval.

15. The leadless cardiac pacemaker (LCP) of claim 11, wherein the second measure of cardiac load is representative of gross movement of the patient.

16. The leadless cardiac pacemaker (LCP) of claim 11, wherein the sensor comprises an accelerometer and the second measure of cardiac load is derived at least in part from a signal outputted from the accelerometer.

17. The leadless cardiac pacemaker (LCP) of claim 11, wherein the controller is further configured to temporarily ignore any changes in the first measure of cardiac load, for at least two heartbeats, in determining the pacing rate.

18. The leadless cardiac pacemaker (LCP) of claim 11, wherein the controller is further configured to determine a plurality of first measures of cardiac load over time based on the received electrical signals, and to determine the pacing rate based on a moving average of two or more of the plurality of first measures of cardiac load.

19. A leadless cardiac pacemaker (LCP) configured to sense and pace a patient'"'"'s heart, the LCP comprising:

two or more electrodes configured to receive electrical signals emanating from the patient'"'"'s heart;

a controller coupled to the two or more electrodes configured to ascertain a first measure of cardiac load based at least in part upon electrical signals received by the two or more electrodes;

the controller further configured to receive a second measure of cardiac load;

the controller further configured to determine a pacing rate based at least in part upon the first measure of cardiac load and the second measure of cardiac load; and

the controller further configured to pace the patient'"'"'s heart in accordance with the determined pacing rate.

20. The leadless cardiac pacemaker (LCP) of claim 19, wherein the first measure of cardiac load comprises a measure that responds more quickly to changes in cardiac activity than the second measure of cardiac load.