SPATIAL CONFIGURATION OF A MOTION SENSOR IN AN IMPLANTABLE MEDICAL DEVICE

• US 20170056666A1
• Filed: 08/22/2016
• Published: 03/02/2017
• Est. Priority Date: 08/27/2015
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Kane, Michael J., Linder, William J., Balczewski, Ron A., Mi, Bin, Hatlestad, John D., Huelskamp, Paul, Maile, Keith R.
• Granted Patent: US 9,968,787 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• 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 1/36578 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 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37235 Aspects of the external programmer
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators

Abstract

Implantable devices having motion sensors. In some examples the a configuration is generated for the implantable device to use the motion sensor in an energy preserving mode in which one or more axis of detection of the motion sensor is disabled or ignored. In some examples the motion sensor outputs along multiple axes are analyzed to determine which axes best correspond to certain patient parameters including patient motion/activity and/or cardiac contractility. In other examples the output of the motion sensor is observed across patient movements or postures to develop conversion parameters to determine a patient standard frame of reference relative to outputs of the motion sensor of an implanted device.

Claims

1. A method of operation in an implantable device, the implantable device comprising a motion sensor, the method comprising:

monitoring an output from a motion sensor along at least first and second axes;

identifying one of the first and second axes as providing less information than one or more other axes; and

at least temporarily disabling the identified axis of the motion sensor.

2. The method of claim 1 wherein the implantable device is a leadless pacemaker configured for implantation within the heart of a patient.

3. The method of claim 1 wherein the motion sensor has three axes.

4. The method of claim 1 wherein the at least temporarily disabling step comprises disabling the identified axis for a predetermined period of time and the method comprises:

re-enabling the temporarily disabled axis; and

repeating the steps of monitoring, identifying and at least temporarily disabling steps.

5. The method of claim 1 further comprising:

while the identified axis is disabled, monitoring the output of the motion sensor on one or more remaining axes;

observing a change in output of the one or more remaining axes; and

re-enabling the identified axis.

6. The method of claim 1 further comprising using an output of the motion sensor from at least one axis which is not at least temporarily disabled to monitor activity of the patient.

7. The method of claim 6 further comprising applying an algorithm for rate responsive pacing to determine a pacing rate for delivery of pacing pulses to the patient using at least an output from the motion sensor, and delivering the rate responsive pacing to the patient.

8. The method of claim 6 further comprising normalizing an output of the motion sensor to a patient frame of reference.

9. A method of initializing an implantable device having a motion sensor comprising:

instructing a patient to perform a first activity;

performing the method of claim 1 to assess motion sensor outputs;

instructing a patient to perform a second activity; and

repeating the method of claim 1 to further assess motion sensor outputs.

10. The method of claim 9 wherein the first activity and second activities are each one of:

assuming a posture selected from the group consisting of sitting, standing, supine, prone, or a sleep position;

or

engaging in physical activity.

11. A method of operation in an implantable device configured for placement inside the heart of a patient, the implantable device comprising a motion sensor, the method comprising:

selecting a first parameter;

observing at least first and second outputs of the motion sensor, the first and second outputs relating to respective first and second axes of measurement for the motion sensor;

correlating at least one of the at least first and second outputs, or a combination thereof, to the first parameter;

storing a first configuration of the at least first and second outputs of the motion detector corresponding to the first parameter;

applying the first configuration to outputs of the motion sensor to monitor characteristics of the first parameter.

12. The method of claim 11 further comprising selecting a second parameter and repeating the observing, and correlating steps, and then:

storing a second configuration of the at least first and second outputs of the motion detector corresponding to the second parameter;

applying the second configuration to outputs of the motion sensor to monitor characteristics of the second parameter.

13. The method of claim 12 wherein the first parameter is cardiac contractility, and the second parameter is patient motion;

further comprising;

using the first configuration to monitor the cardiac contractility of the patient and generate diagnostic data therefrom for use by a physician; and

using the second configuration to monitor the activity level of the patient and facilitate a rate responsive pacing output regimen for the patient.

14. The method of claim 13 further comprising the implantable device delivering the rate responsive pacing output regimen to the patient.

15. The method of claim 11 wherein the first parameter is patient motion and the method further comprises:

delivering pacing therapy to the patient via the implantable medical device; and

using the first configuration to facilitate a rate responsive pacing output regimen for the patient in which the rate at which pacing therapy is delivered adjusts in view of patient activity.

16. The method of claim 11 wherein the implantable device includes a sensing circuit for sensing cardiac electrical signals of the patient, and the method further comprises:

using a sensed cardiac electrical signal, determining that a cardiac event took place;

using the stored configuration, analyzing one or more outputs from the motion sensor to determine a state of the parameter during the cardiac event.

17. A method of operation in an implantable device configured for placement inside the heart of a patient, the implantable device comprising a motion sensor, the method comprising:

capturing a plurality of outputs of the motion sensor for at least first and second axes of the motion sensor;

establishing a standard frame of reference for the patient using the outputs of the motion sensor.

18. The method of claim 17 wherein the capturing step is performed by having the patient assume a series of postures.

19. The method of claim 18 further comprising capturing an output of a second device while the patient assumes the series of postures, wherein the step of establishing a standard frame of reference is performed by comparing an output from the second device to the captured plurality of outputs of the motion sensor.

20. The method of claim 18 wherein the step of having the patient assume a series of postures is performed by having a programmer provide an instruction for the patient and await an indication that the patient has complied.