Methods for data retention in an implantable medical device

• US 20060287691A1
• Filed: 11/02/2005
• Published: 12/21/2006
• Est. Priority Date: 11/02/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Drew, Touby A.
• Granted Patent: US 10,111,613 B2
• Time in Patent Office: Days
• US Class Current: 607/59
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/165 Evaluating the state of mind, e.g. depression, anxiety
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4082 Diagnosing or monitoring movement diseases, e.g. Parkinson, Huntington or Tourette
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61N 1/36132 using patient feedback
• CPC Class Codes: A61N 1/3614 based on impedance measurement
• CPC Class Codes: A61N 1/36521 : the parameter being derived from measurement of an electrical impedance
• 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 1/37252 : Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
• CPC Class Codes: A61N 1/37282 : characterised by communication with experts in remote locations using a network
• CPC Class Codes: G06F 16/2272 : Management thereof
• CPC Class Codes: G16H 10/60 : for patient-specific data, e.g. for electronic patient records
• CPC Class Codes: G16H 10/65 : stored on portable record carriers, e.g. on smartcards, RFID tags or CD
• CPC Class Codes: G16H 20/30 : relating to physical therapies or activities, e.g. physiotherapy, acupressure or exercising
• CPC Class Codes: G16H 40/63 : for local operation
• CPC Class Codes: G16H 40/67 : for remote operation

Abstract

Methods for storing data records associated with a medical monitoring event in a data structure. An implanted device obtains data and stores the data in the data record in a first data structure that is age-based. Before an oldest data record is lost, the oldest data record may be stored in a second data structure that is priority index-based. The priority index may be determined by a severity level and may be further determined by associated factors. The implanted device may organize, off-load, report, and/or display a plurality of data records based on an associated priority index. Additionally, the implanted device may select a subset or composite of physiologic channels from the available physiologic channels based on a selection criterion.

Claims

1. A method for retaining physiologic data in an implantable medical device, wherein the physiologic data comprises an old data record being stored in a first data structure and having an old priority index, the method comprising:

(A) receiving a new data record;

(B) determining a new priority index of the new data record;

(C) replacing at least a portion of the old data record with at least a portion of the new data record in the first data structure; and

(D) if the old priority index exceeds a threshold criterion, storing at least a portion of the old data record in a second data structure.

2. The method of claim 1, wherein (D) is performed only if the old priority index is greater than an other priority index of another data record in the second data structure, and wherein the other data record is deleted.

3. The method of claim 1, further comprising:

(E) determining the old priority index by determining an old severity level that is associated with the old data record, wherein the old severity level is a metric of an associated neurological event'"'"'s severity.

4. The method of claim 3, wherein (E) further comprises:

(i) determining an age of the old data record; and

(ii) determining the old priority index as a function of the age and the old severity level.

5. The method of claim 3, wherein the old severity level is dependent on at least one neurological signal characteristic selected from the group consisting of a duration of a neurological cluster, a spread of the neurological cluster, and a statistic of the neurological signal.

6. The method of claim 3, further comprising:

(i) obtaining information of at least one external event; and

(ii) determining the old priority index as a function of the information and the old severity level.

7. The method of claim 6, wherein the at least one external event is selected from the group consisting of a cardiac event, a chemical event, a scheduling event, a patient-initiated event, a physician-initiated event, and a device-based event.

8. The method of claim 3, further comprising:

(i) determining an event class of a corresponding event is associated with the physiologic data; and

(ii) determining the old priority index as a function of the event class and the old severity level.

9. The method of claim 1, further comprising:

(E) deleting selected data from at least one data record.

10. The method of claim 9, wherein (E) comprises reducing data precision of a portion of the at least one data record.

11. The method of claim 9, wherein (E) comprises eliminating an attribute of the at least one data record.

12. The method of claim 1, wherein (A) further comprises:

(i) selecting at least a first physiologic channel from a plurality of physiologic channels; and

(ii) including at least one data sample from the at least first physiologic channel into the new data record.

13. The method of claim 12, wherein the first physiologic channel corresponds to a highest clinical relevance of the plurality of physiologic channels.

14. The method of claim 13, further comprising:

(iii) selecting another physiologic channel from the plurality of physiologic channels, wherein the other physiologic channel corresponds to the next highest clinical relevance of the plurality of physiologic channels.

15. The method of claim 13, further comprising:

(iii) selecting another physiologic channel from the plurality of physiologic channels, wherein the other physiologic channel corresponds to a predetermined fraction of the highest clinical relevance.

16. The method of claim 13, further comprising:

(iii) processing each physiologic channel of the plurality of physiologic channels with a window function.

17. The method of claim 16, wherein the first physiologic channel corresponds to a highest clinical relevance.

18. The method of claim 17, further comprising:

(iv) selecting an other physiologic channel from the plurality of physiologic channels, wherein the other physiologic channel corresponds to a next highest clinical relevance.

19. The method of claim 17, further comprising:

(iv) selecting another physiologic channel from the plurality of physiologic channels, wherein the other physiologic channel corresponds to a predetermined fraction of the highest clinical relevance.

20. The method of claim 12, wherein (i) comprises sorting the plurality of physiologic channels by relevancy and keeping a selected number of physiologic channels that have a largest degree of relevancy.

21. The method of claim 20, wherein the relevancy is associated with a function, and wherein factors of the function are selected from the group consisting of an onset time, presence of a physiologic event, and a severity measure of the physiologic event.

22. The method of claim 1, wherein the second data structure does not contain available memory and wherein (D) comprises removing at least a portion of another data record from the second data structure, wherein the removed portion of the other data record occupies memory space.

23. The method of claim 1, wherein (D) is performed only if the old priority index is greater than another priority index of another data record in the second data structure, and wherein the other data record is marked for deletion.

24. The method of claim 1, wherein (D) is performed only if the old priority index is greater than another priority index of another data record in the second data structure, and wherein the other data record is off-loaded to an external device.

25. The method of claim 1, wherein (D) is performed only if the old priority index is greater than another priority index of another data record in the second data structure, and wherein the other data record is overwritten.

26. The method of claim 1, wherein (C) comprises storing the portion of the new data record in the first data record, wherein the portion of the new data record is a pointer to new data;

and wherein the portion of the old data record that is replaced in (C) and potentially stored in (D) is a pointer to old data.

27. The method of claim 1, wherein (A) comprises receiving an indication from a patient to initiate recording.

28. The method of claim 1, wherein (D) comprises compressing at least a portion of the old data record that is stored in the second data structure

29. A method for retaining physiologic data in an implantable medical device comprising:

(A) receiving a new data record;

(B) storing least a first portion of the new data record in a first data structure;

(C) determining a new priority index of the new data record; and

(D) if the new priority index exceeds a threshold criterion, storing at least a second portion of the new data record in a second data structure.

30. The method of claim 29,wherein (A) comprises receiving an indication from a patient to initiate recording.

31. The method of claim 29, wherein (D) comprises if the new priority index exceeds a threshold criterion, removing the stored first portion of the new data record in the first data structure.

32. The method of claim 29, wherein the first portion is the same as the second portion.

33. The method of claim 29, wherein the second portion is a subset of the first portion.