Template matching method for monitoring of ECG morphology changes

• US 7,996,070 B2
• Filed: 04/24/2008
• Issued: 08/09/2011
• Est. Priority Date: 04/24/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Mouton, Suzanne, van Dam, Peter, Oosterhoff, Peter
• Primary Examiner(s): Schaetzle; Kennedy J
• Application Number:
  US12/108,655
• Publication Number:
  US 20090270747A1
• Time in Patent Office: 1,202 Days
• Field of Search: None
• US Class Current: 600/509
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61N 1/36535 controlled by body position or posture
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

An implantable medical device and associated method perform ECG morphology monitoring. A subcutaneous ECG signal and a posture signal are sensed in a patient. A cardiac condition is detected in response to the ECG signal and the posture signal. In one embodiment, multiple ECG morphology templates corresponding to each of a number of different patient postures are acquired and stored for use in detecting a cardiac condition.

Claims

1. A method for use in an implantable medical device, comprising:

sensing a subcutaneous ECG signal in a patient;

sensing a signal corresponding to a posture of the patient;

detecting a cardiac condition in response to the ECG signal and the posture signal;

detecting a change in a morphology of the ECG signal in response to the ECG signal; and

detecting an unstable posture of the patient in response to the posture signal; and

wherein detecting a cardiac condition comprises waiting for a stable posture signal to be detected.

2. The method of claim 1, wherein detecting a cardiac condition comprises determining if the patient posture has changed.

3. The method of claim 1, further comprising:

detecting a plurality of patient postures in response to the posture signal;

acquiring and storing an ECG morphology template corresponding to each of the plurality of patient postures;

wherein detecting a cardiac condition comprises

determining a current ECG signal morphology,

determining a current patient posture,

selecting one of the stored ECG morphology templates corresponding to the current patient posture; and

comparing the current ECG signal morphology to the selected one of the ECG morphology templates.

4. The method of claim 3, further comprising

detecting a change in patient posture,

wherein the current ECG signal morphology is determined in response to detecting the change in patient posture.

5. A method for use in an implantable medical device, comprising:

sensing a subcutaneous ECG signal in a patient;

sensing a signal corresponding to a posture of the patient;

detecting a cardiac condition in response to the ECG signal and the posture signal;

detecting a plurality of patient postures in response to the posture signal; and

acquiring and storing an ECG morphology template corresponding to each of the plurality of patient postures;

wherein detecting a cardiac condition comprises

determining a current ECG signal morphology,

determining a current patient posture,

selecting one of the stored ECG morphology templates corresponding to the current patient posture; and

comparing the current ECG signal morphology to the selected one of the ECG morphology templates;

wherein acquiring and storing the ECG morphology template corresponding to each of the plurality of patient postures comprises storing a first template corresponding to a first ECG signal portion and a second template corresponding to a second ECG signal portion, the first and second signal portions each occurring at different times within a cardiac cycle,

wherein detecting a cardiac condition comprises determining if the current ECG signal morphology matches a single one of the first and second templates corresponding to the current patient posture.

6. A medical device, comprising:

a pair of subcutaneous ECG electrodes for sensing an ECG signal in a patient;

a sensor for sensing a signal corresponding to a posture of the patient;

a processor coupled to the ECG electrodes and the posture sensor and configured to detect a cardiac condition in response to the ECG signal and the posture signal, wherein detecting a cardiac condition comprises;

detecting a change in a morphology of the ECG signal in response to the ECG signal;

detecting an unstable posture of the patient in response to the posture signal; and

waiting for a stable posture signal to be detected.

7. The device of claim 6 wherein detecting a cardiac condition comprises determining if the patient posture has changed.

8. The device of claim 6 further comprising a memory coupled to the processor,

wherein the processor is further configured to detect a plurality of patient postures in response to the posture signal, and acquire and store in the memory an ECG morphology template corresponding to each of the plurality of patient postures;

wherein detecting a cardiac condition comprises

determining a current ECG signal morphology,

determining a current patient posture,

selecting one of the stored ECG morphology templates corresponding to the current patient posture; and

comparing the current ECG signal morphology to the selected one of the ECG morphology templates.

9. The device of claim 8 wherein the processor is further configured to detect a change in patient posture,

wherein the current ECG signal morphology is determined in response to detecting the change in patient posture.

10. A medical device, comprising:

a pair of subcutaneous ECG electrodes for sensing an ECG signal in a patient;

a sensor for sensing a signal corresponding to a posture of the patient;

a processor coupled to the ECG electrodes and the posture sensor and configured to detect a cardiac condition in response to the ECG signal and the posture signal;

wherein the processor is further configured to detect a plurality of patient postures in response to the posture signal, and to acquire and store in the memory an ECG morphology template corresponding to each of the plurality of patient postures;

wherein detecting a cardiac condition comprises

determining a current ECG signal morphology,

determining a current patient posture,

selecting one of the stored ECG morphology templates corresponding to the current patient posture; and

comparing the current ECG signal morphology to the selected one of the ECG morphology templates;

wherein detecting a cardiac condition comprises determining if the current ECG signal morphology matches a single one of the first and second templates corresponding to the current patient posture.