Implantable Medical Device Diagnostic Data Acquisition and Storage

• US 20080058651A1
• Filed: 09/05/2006
• Published: 03/06/2008
• Est. Priority Date: 09/05/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Bange, Joseph E., Koshiol, Allan T., Shen, Zhe
• Granted Patent: US 7,756,573 B2
• Time in Patent Office: Days
• US Class Current: 600/481
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/335 using integrated circuit memory devices
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371

Abstract

A method carried out by a therapeutic implantable medical device includes detecting a plurality of physiologic episodes of interest, recording a single set of diagnostic data indicative of physiologic activity, determining that the single set of diagnostic data corresponds in time with at least two physiologic episodes, and associating the single set of diagnostic data with the least two of the plurality of physiologic episodes. As such, requests for diagnostic data associated with any of the at least two of the plurality of physiologic episodes are satisfied with diagnostic data from the single set of recorded diagnostic data.

Claims

1. A method carried out by a therapeutic implantable medical device (IMD), the method comprising:

detecting a plurality of physiologic episodes of interest;

recording a single set of diagnostic data indicative of physiologic activity;

determining that the single set of diagnostic data corresponds in time with at least two physiologic episodes; and

associating the single set of diagnostic data with the least two of the plurality of physiologic episodes, whereby requests for diagnostic data associated with any of the at least two of the plurality of physiologic episodes are satisfied with diagnostic data from the single set of recorded diagnostic data.

2. The method as recited in claim 1, further comprising:

receiving a request for diagnostic data related to one of the at least two physiologic episodes;

in response to receiving the request for diagnostic data related to one of the at least two physiologic episodes, returning the single set of diagnostic data;

receiving a request for diagnostic data related to another one of the at least two physiologic episodes; and

in response to receiving the request for diagnostic data related to another one of the at least two physiologic episodes, returning the single set of diagnostic data.

3. The method as recited in claim 1 further comprising:

prioritizing the plurality of physiologic episodes based on episode types associated with the physiologic episodes;

specifying a minimum number associated with each episode type, wherein the minimum number indicates a minimum number of sets of diagnostic data to be recorded for the associated episode type; and

specifying a maximum number associated with each episode type, wherein the maximum number indicates a maximum number of sets of diagnostic data to be recorded for the associated episode type.

4. The method as recited in claim 1 further comprising:

associating a therapy delivery attempt with one of the at least two of the plurality of physiologic episodes, wherein the therapy delivery attempt occurs at a time after the associated cardiac episode;

recording another set of diagnostic data at the time of the therapy delivery attempt;

associating the another set of diagnostic data with the associated physiologic episode.

5. The method as recited in claim 1, wherein the recorded set of diagnostic data comprises one of electrogram data, marker data, processed waveform data, or other physiologic sensor data.

6. The method as recited in claim 5, further comprising compressing the single set of diagnostic data using differential pulse code modulation (DPCM) and Huffman encoding.

7. The method as recited in claim 1, wherein recording the single set of diagnostic data comprises copying diagnostic data from a circular buffer into another part of memory.

8. A method for managing memory in an implantable medical device, the method comprising:

receiving diagnostic data;

detecting a first physiologic event of interest based on analysis of the diagnostic data;

in response to detecting the first physiologic event, recording diagnostic data that is received during a first time span ending at a first specified end time;

detecting a second physiologic event of interest during the first time span;

in response to detecting the second physiologic event of interest, specifying a second end time;

continuing to record diagnostic data that is received during a second time span ending at the second specified end time, to form a single set of diagnostic data associated with both the first physiologic event and the second physiologic event, wherein the single set of diagnostic data is composed of diagnostic data received during the first time span and the second time span;

in response to receiving a request for diagnostic data related to the first physiologic event, returning the single set of diagnostic data; and

in response to receiving a request for diagnostic data related to the second physiologic event, returning the single set of diagnostic data.

9. A method as recited in claim 8 wherein the IMD is operable to deliver therapy, and wherein the method further comprises:

delivering therapy during the first time span or the second time span;

in response to delivering therapy, specifying a third end time; and

continuing to record diagnostic data that is received during a third time span ending at the third specified end time, wherein the diagnostic data received during the third time span is included in the single set of diagnostic data.

10. A method as recited in claim 9 further comprising associating the delivering of therapy with one of the first physiologic event or the second physiologic event.

11. A method as recited in claim 10, further comprising returning data descriptive of the delivering of therapy in response to receiving a request for diagnostic data related to the physiologic event that is associated with the delivering of therapy.

12. A method as recited in claim 8, further comprising associating the first physiologic event with the single set of diagnostic data by determining that the first physiologic event occurred at a time included in the first time span.

13. A method as recited in claim 8, wherein recording diagnostic data comprises recording one of electrogram data, marker data, processed waveform data, or other physiologic sensor data.

14. A method as recited in claim 8, further comprising prioritizing the first physiologic event and the second physiologic event based on a first event type and a second event type, respectively.

15. A method as recited in claim 14, further comprising:

detecting a third physiologic event of a third event type having a higher priority than the first physiologic event;

in response to detecting the third physiologic event, recording diagnostic data to form another set of diagnostic data;

determining whether more than a specified minimum number of sets of diagnostic data associated with events of the first event type exist in memory; and

deleting the first set of diagnostic data associated with the first physiologic event if more than the specified minimum number of sets of diagnostic data associated with events of the first event type exist in memory.

16. A method as recited in claim 14, further comprising:

detecting a third physiologic event of a third event type; and

recording diagnostic data to form another set of diagnostic data associated with the third physiologic event if a specified maximum number of sets of diagnostic data associated with the third event type do not exist in memory.

17. A method as recited in claim 8, wherein the IMD is operable to deliver therapy, and wherein the method further comprises:

generating a physiologic event data structure associated with, and descriptive of the first physiologic event;

detecting one or more attempts to deliver therapy in response to detecting the first physiologic event;

for each of the one or more attempts to deliver therapy, generating a therapy delivery attempt data structure associated with, and descriptive of, the therapy delivery attempt; and

associating all of the therapy delivery attempt data structures with the physiologic event data structure.

18. A method as recited in claim 17, wherein associating all of the therapy deliver attempt data structures with the physiologic event data structure comprises generating a linked list of the therapy delivery attempt data structures.

19. A method as recited in claim 8, wherein recording diagnostic data comprises copying diagnostic data from a circular buffer into another part of memory.

20. An implantable medical device (IMD) configured for implantation in a patient to monitor cardiac activity in, and deliver therapy to, the patient'"'"'s heart, the IMD comprising:

a pulse generator operable to deliver pacing pulses and shock pulses;

a plurality of leads having proximate ends coupled to the pulse generator and distal ends affixed to the patient'"'"'s heart at selected locations, wherein the leads are configured to pick up electrical activity in the patient'"'"'s heart, and wherein the leads are further configured to deliver the pacing pulses and the shock pulses to the patient'"'"'s heart;

a communication module operable to communicate diagnostic data to a device external to the patient;

a memory storing a prioritization schedule of cardiac episodes, wherein the prioritization schedule specifies a priority for each of a plurality of types of cardiac episodes, a minimum number indicating a minimum number of data sets to be recorded for each of the cardiac episodes, and a maximum number indicating a maximum number of data sets to be recorded for each of the cardiac episodes; and

a processor operable to delete a first recorded set of diagnostic data associated with a type of cardiac episode of a first priority, only if a second received set of diagnostic data is associated with a type of cardiac episode of a second priority that is higher than the first priority, and deletion of the first set of diagnostic data would not result in fewer sets of diagnostic data than the minimum number specified for the type of episode associated with the first set of diagnostic data.

21. The IMD as recited in claim 20, wherein the processor is further operable to delete the first set of diagnostic data only if fewer than the maximum number of sets of diagnostic data specified for the type of episode associated with the second set of diagnostic data have been recorded.

22. The IMD as recited in claim 20, further comprising a circular buffer receiving diagnostic data.