Method and apparatus for beat acquisition during template generation in a medical device having dual sensing vectors

• US 10,188,867 B2
• Filed: 01/23/2015
• Issued: 01/29/2019
• Est. Priority Date: 01/23/2015
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Zhang, Xusheng
• Primary Examiner(s): Carey, Michael
• Application Number:
  US14/604,260
• Publication Number:
  US 20160213941A1
• Time in Patent Office: 1,467 Days
• Field of Search: 607 7, 607 60
• 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 5/6869 Heart
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3624 occurring in the atrium, i.e. atrial tachycardia
• CPC Class Codes: A61N 1/36507 controlled by gradient or slope of the heart potential
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

A method and medical device for generating a template that includes sensing a cardiac signal from a plurality of electrodes, determining a plurality of beats in response to the sensed cardiac signal, determining whether to store a beat of the plurality of beats in a subgroup of a plurality of subgroups for storing beats, determining whether a number of beats stored in one of the plurality of subgroups exceeds a subgroup threshold, and generating a template in response to beats stored in the one of the plurality of subgroups that exceeds the subgroup threshold.

Claims

1. A medical device for generating a template, comprising:

a plurality of electrodes configured to sense a cardiac signal;

a storage device comprising a plurality of subgroups for storing beats; and

a processor configured to;

identify a plurality of beats in the sensed cardiac signal,

determine that a first beat of the plurality of beats is an initial beat to be stored in the first subgroup of the plurality of subgroups,

set the first beat as a first subgroup template beat in response to the first beat being the initial beat,

determine, for each remaining beat of the plurality of beats, whether to store the beat within a subgroup of the plurality of subgroups of the storage device,

determine whether a number of beats stored in one of the plurality of subgroups exceeds a subgroup threshold, and in response to the number of beats stored in the one of the plurality of subgroups exceeding the subgroup threshold, and

generate a template beat using one or more beats of the one of the plurality of subgroups that exceeds the subgroup threshold.

2. The medical device of claim 1, wherein the processor is configured to compare a second beat of the plurality of beats to the first subgroup template beat and determine a match between the second beat and the first subgroup template beat, determine whether the match is greater than a match threshold, and store the second beat within the first subgroup in response to the match being greater than the match threshold.

3. The medical device of claim 2, wherein the processor is configured to determine, in response to the match not being greater than the match threshold, whether a second subgroup has been created, create a second subgroup in response to a second subgroup having not been created, and set the second beat as a second subgroup template beat.

4. The medical device of claim 3, wherein the processor is configured to compare the second beat to a second subgroup template beat of the second subgroup in response to a second subgroup having been created, determine a match between the second beat and the second subgroup template beat, determine whether the match between the second beat and the second subgroup template beat is greater than the match threshold, and store the second beat within the second subgroup in response to the match between the second beat and the second subgroup template beat being greater than the match threshold.

5. The medical device of claim 2, wherein the processor is configured to compare the second beat to a second subgroup template beat of a second subgroup and determine a match between the second beat and the second subgroup template beat in response to the match between the second beat and the first subgroup template beat not being greater than the match threshold, determine whether the match between the second beat and the second subgroup template beat is greater than the match threshold, and store the second beat within the second subgroup in response to the match between the second beat and the second subgroup template beat being greater than the match threshold.

6. The medical device of claim 1, wherein the plurality of beats comprises 15 beats and the subgroup threshold comprises 10 beats.

7. The medical device of claim 6, wherein the plurality of subgroups comprises 4 subgroups.

8. The medical device of claim 1, wherein the plurality of beats is a first plurality of beats, and wherein the processor is further configured to identify a next plurality of beats in the sensed cardiac signal, in response to the number of beats stored in each of the plurality of subgroups not exceeding the subgroup threshold, determine, for each of the next plurality of beats, whether to store the beat within the one of the plurality of subgroups, determine whether a number of beats of the next plurality of beats stored in the one of the plurality of subgroups exceeds the subgroup threshold, and generate the template beat using one or more of the beats of the next plurality of beats stored in the one of the plurality of subgroups that exceeds the subgroup threshold.

9. The medical device of claim 1, wherein the plurality of electrodes form a first sensing vector sensing a first interval of the cardiac signal during a predetermined time period and a second sensing vector simultaneously sensing a second interval of the cardiac signal during the predetermined time period, and wherein the processor is configured to determine interval conditions based on the first interval and the second interval, and determine whether to identify the first interval and the second interval as qualified intervals for generating a template based on the determined intervals conditions.

16. The medical device of claim 1, wherein the processor is configured to generate the template beat by averaging the beats stored within the one of the plurality of subgroups that exceeds the subgroup threshold.

17. The medical device of claim 1, wherein the processor is further configured to:

detect a cardiac event based at least on a comparison of beats subsequent the plurality of beats to the generated template beat; and

control the medical device to deliver a therapy in response to the detection of the cardiac event.

18. The medical device of claim 17, further comprising a high voltage output circuit to deliver the therapy, wherein the therapy comprises an anti-tachyarrhythmia shock.

19. The medical device of claim 1, wherein the plurality of beats is a first plurality of beats, and wherein the processor is configured to, for each of the plurality of subgroups, compare a beat of the first plurality of beats to a respective subgroup template beat and determine a match between the beat and the subgroup template beat, determine whether the match is greater than a match threshold, and, in response to determining that the match is not greater than a match threshold for each of the plurality of subgroup template beats, discard the first plurality of beats and identify a second plurality of beats in the sensed cardiac signal,

wherein the processor is configured to determine, for each of the next plurality of beats, whether to store the beat within the one of the plurality of subgroups, determine whether a number of beats of the next plurality of beats stored in the one of the plurality of subgroups exceeds the subgroup threshold, and generate the template beat using one or more of the beats of the next plurality of beats stored in the one of the plurality of subgroups that exceeds the subgroup threshold.

10. A subcutaneous cardiac device for generating a template, comprising:

a plurality of electrodes configured to sense a cardiac signal;

a storage device;

a processor configured to;

identify a plurality of beats in the sensed cardiac signal,

determine that a first beat of the plurality of beats is an initial beat to be stored in the first subgroup of the plurality of subgroups,

set the first beat as a first subgroup template beat in response to the first beat being the initial beat,

determine, for each remaining beat of the plurality of beats, whether to store the beat within a subgroup of a plurality of subgroups of the storage device,

determine whether a number of beats stored in one of the plurality of subgroups exceeds a subgroup threshold,

generate a template beat in response to the number of beats stored in the one of the plurality of subgroups exceeding the subgroup threshold using one or more beats stored in the one of the plurality of subgroups that exceeds the subgroup threshold,

and

detect a cardiac event based at least on a comparison of beats subsequent the plurality of beats to the generated template beat; and

a high voltage output circuit to deliver therapy via electrodes of the plurality of electrodes in response to the processor detecting the cardiac event.

11. The subcutaneous cardiac device of claim 10, wherein the processor is configured to compare a second beat of the plurality of beats to the first subgroup template beat and determine a match between the second beat and the first subgroup template beat, determine whether the match is greater than a match threshold, and store the second beat within the first subgroup in response to the match being greater than the match threshold.

12. The subcutaneous cardiac device of claim 11, wherein the processor is configured to determine, in response to the match not being greater than the match threshold, whether a second subgroup has been created, and set the second beat as a second subgroup template beat in response to a second beat subgroup not being created.

13. The subcutaneous cardiac device of claim 12, wherein the processor is configured to compare the second beat to a second subgroup template beat of the second subgroup in response to a second subgroup being created, determine a match between the second beat and the second subgroup template beat, determine whether the match between the second beat and the second subgroup template beat is greater than the match threshold, and store the second beat within the second subgroup in response to the match between the second beat and the second subgroup template beat being greater than the match threshold.

14. The subcutaneous cardiac device of claim 11, wherein the processor is configured to compare the second beat to a second subgroup template beat of a second subgroup and determine a match between the second beat and the second subgroup template beat in response to the match between the second beat and the first subgroup template beat not being greater than the match threshold, determine whether the match between the second beat and the second subgroup template beat is greater than the match threshold, and store the second beat within the second subgroup in response to the match between the second beat and the second subgroup template beat being greater than the match threshold.

15. The subcutaneous cardiac device of claim 10, wherein the plurality of beats is a first plurality of beats, and wherein the processor is further configured to identify a next plurality of beats in the sensed cardiac signal in response to the number of beats stored in the one of the plurality of subgroups not exceeding the subgroup threshold, determine, for each of the next plurality of beats, whether to store the beat within the one of the plurality of subgroups, determine whether a number of beats of the next plurality of beats stored in the one of the plurality of subgroups exceeds the subgroup threshold, and generate the template beat using one or more of the beats of the next plurality of beats stored the in one of the plurality of subgroups that exceeds the subgroup threshold.

20. The subcutaneous cardiac device of claim 10, wherein the plurality of beats is a first plurality of beats, and wherein the processor is configured to, for each of the plurality of subgroups, compare a beat of the first plurality of beats to a respective subgroup template beat and determine a match between the beat and the subgroup template beat, determine whether the match is greater than a match threshold, and, in response to determining that the match is not greater than a match threshold for each of the plurality of subgroup template beats, discard the first plurality of beats and identify a second plurality of beats in the sensed cardiac signal,

wherein the processor is configured to determine, for each of the next plurality of beats, whether to store the beat within the one of the plurality of subgroups, determine whether a number of beats of the next plurality of beats stored in the one of the plurality of subgroups exceeds the subgroup threshold, and generate the template beat using one or more of the beats of the next plurality of beats stored in the one of the plurality of subgroups that exceeds the subgroup threshold.