Calibration of implantable device orientation

Patent metadata

Field	Value
Publication number	US-11890101-B2
Application number	US-202016940250-A
Country	US
Kind code	B2
Filing date	Jul 27, 2020
Priority date	Aug 2, 2019
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

Systems and methods for calibrating an orientation of an implantable device in a patient is described. An exemplary system includes a calibration circuit that can receive acceleration information sensed from an implantable medical device (IMD) implanted in a patient, and receive reference acceleration information sensed from a reference device associated with the patient. The acceleration information and the reference acceleration information are acquired when the patient assumes a first posture or in a first position. The calibration circuit determines a spatial relationship between an orientation of the IMD and a reference orientation of the reference device using the received acceleration information and the received reference acceleration information, and calibrate subsequent acceleration information sensed from the IMD using the determined spatial relationship to correct for the orientation of the IMD.

First claim

What is claimed is:

1. A system, comprising:
a calibration circuit configured to:
receive acceleration information sensed from an implantable medical device (IMD);
receive reference acceleration information sensed from a reference device associated with a patient, the reference device separate from the IMD;
determine a spatial relationship between an orientation of the IMD and a reference orientation of the reference device using the received acceleration information and the received reference acceleration information;
determine the orientation of the IMD or calibrate subsequent acceleration information sensed from the IMD using the determined spatial relationship to correct for the orientation of the IMD; and
generate a device diagnostic indicative of one or more of a rotation, a flip, or a migration of the IMD based at least in part on the determined orientation of the IMD.

2. The system of claim 1 , wherein the received acceleration information and the received reference acceleration information are both acquired with respect to a first posture of the patient, and wherein the reference device is a non-implantable device adapted to be adjustably positioned on a body of the patient such that the reference orientation is substantially aligned with a body orientation of the patient in the first posture.

3. The system of claim 1 , wherein the reference device is configured to communicate with the IMD via a wireless communication link, and wherein:
the IMD includes an accelerometer configured to sense the acceleration information; and
the reference device includes a reference accelerometer configured to sense the reference acceleration information.

4. The system of claim 1 , wherein the reference device is personal mobile device.

5. The system of claim 2 , wherein the subsequent acceleration information is sensed from the IMD when the patient assumes a different posture than the first posture.

6. The system of claim 2 , wherein the received acceleration information includes acceleration measurements from the IMD along one or more axes, and the received reference acceleration information includes reference acceleration measurements from the reference device along one or more axes, and wherein the calibration circuit is configured to:
generate an IMD orientation representation using the acceleration measurements;
generate a reference orientation representation using the reference acceleration measurements; and
determine the spatial relationship including a rotation matrix that transforms the IMD orientation representation to the reference orientation representation.

7. The system of claim 6 , wherein the calibration circuit is configured to:
receive supplemental acceleration information sensed from the IMD and supplemental reference acceleration information sensed from the reference device, the supplemental acceleration information and the supplemental reference acceleration information acquired when the patient assumes a second posture different from the first posture; and
determine the spatial relationship further using the supplemental acceleration information and the received supplemental reference acceleration information.

8. The system of claim 7 , wherein the supplemental acceleration information includes acceleration measurements from the IMD along one or more axes, and the supplemental reference acceleration information includes reference acceleration measurements from the reference device along one or more axes, and wherein the calibration circuit is configured to:
generate an augmented IMD orientation representation using the acceleration measurements and the supplemental acceleration measurements;
generate an augmented reference orientation representation using the reference acceleration measurements and the supplemental reference acceleration measurements; and
determine the rotation matrix that transforms the augmented IMD orientation representation to the augmented reference orientation representation.

9. The system of claim 7 , wherein the first posture is substantially orthogonal to the second posture.

10. The system of claim 6 , wherein the calibration circuit is configured to:
receive magnetic field information sensed from the IMD and receive reference magnetic field information sensed from the reference device, the magnetic field information and the reference magnetic field information both acquired when the patient assumes the first posture;
generate an augmented IMD orientation representation using the acceleration measurements and the received magnetic field information;
generate an augmented reference orientation representation using the reference acceleration measurements and the received reference magnetic field information; and
determine the rotation matrix that transforms the augmented IMD orientation representation to the augmented reference orientation representation.

11. The system of claim 10 , wherein the IMD includes a magnetometer configured to measure a magnetic field, and the reference device includes a reference magnetometer configured to measure a reference magnetic field, when the patient assumes the first posture.

12. The system of claim 1 , further comprising a detector circuit configured to detect a target physiological event or a status of the IMD using the calibrated subsequent acceleration information.

13. The system of claim 1 , further comprising a user interface configured to generate an alert of the determined IMD orientation.

14. A method, comprising:
receiving acceleration information sensed from an implantable medical device (IMD);
receiving reference acceleration information sensed from a reference device associated with a patient, the reference device separated from the IMD;
determining a spatial relationship between an orientation of the IMD and a reference orientation of the reference device using the received acceleration information and the received reference acceleration information;
acquiring subsequent acceleration information from the IMD;
determining the orientation of the IMD or calibrating the subsequent acceleration information using the determined spatial relationship to correct for the orientation of the IMD; and
generating a device diagnostic indicative of one or more of a rotation, a flip, or a migration of the IMD based at least in part on the determined orientation of the IMD.

15. The method of claim 14 , wherein the received acceleration information includes acceleration measurements from the IMD along one or more axes, and the received reference acceleration information includes reference acceleration measurements from the reference device along one or more axes, the received acceleration information and the received reference acceleration information both acquired with respect to a first posture of the patient, and wherein determining the spatial relationship includes:
generating an IMD orientation representation using the acceleration measurements;
generating a reference orientation representation using the reference acceleration measurements; and
determining the spatial relationship including a rotation matrix that transforms the IMD orientation representation to the reference orientation representation.

16. The method of claim 15 , comprising:
when the patient assumes a second posture different from the first posture, receiving supplemental acceleration information from the IMD and acquiring supplemental reference acceleration information from the reference device; and
determining the spatial relationship further using the supplemental acceleration information and the received supplemen

Assignees

• Cardiac Pacemakers Inc

Inventors

• Shute Jonathan Bennett
• Hatlestad John D
• Saha Sunipa
• Perschbacher David L

Classifications

• A61B5/29

  for permanent or long-term implantation · CPC title

• A61B5/686 Primary

  Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence) · CPC title

• A61B5/1116

  Determining posture transitions · CPC title

• A61B5/333 Primary

  Recording apparatus specially adapted therefor · CPC title

• A61B5/0022

  Monitoring a patient using a global network, e.g. telephone networks, internet · CPC title