Systems and methods for sensing vector selection in an implantable medical device

• US 20070276445A1
• Filed: 05/26/2006
• Published: 11/29/2007
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Cameron Incorporated (Schlumberger NV)
• Original Assignee: Cameron Incorporated (Schlumberger NV)
• Inventors: Sanghera, Rick, Allavatam, Venugopal
• Granted Patent: US 8,788,023 B2
• Time in Patent Office: Days
• US Class Current: 607/28
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/3918 characterised by shock pathway, e.g. by electrode configuration
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

Methods and devices for sensing vector analysis in an implantable cardiac stimulus system. In an illustrative example, a first sensing vector is analyzed to determine whether it is suitable, within given threshold conditions, for use in cardiac event detection and analysis. If so, the first vector may be selected for detection and analysis. Otherwise, one or more additional vectors are analyzed. A detailed example illustrates methods for analyzing sensing vectors by the use of a scoring system. Devices adapted to perform these methods are also discussed, including implantable medical devices adapted to perform these methods, and systems comprising implantable medical devices and programmers adapted to communicate with implantable medical devices, the systems also being adapted to perform these methods. Another example includes a programmer configured to perform these methods including certain steps of directing operation of an associated implanted or implantable medical device.

Claims

1. A method involving:

an implantable medical system adapted to define a plurality of sensing vectors between electrodes implanted in a patient, and

a programmer adapted for communication with the implantable medical device;

the method comprising;

the implantable medical system capturing cardiac signal data using at least one of the plurality of sensing vectors;

analyzing data related to the captured cardiac signal data and either;

determining that an identified sensing vector is suitable for cardiac event detection;

or

determining that one or more sensing vectors is to be analyzed.

2. The method of claim 1, wherein, if it is determined that one or more sensing vectors is to be analyzed, the method further comprises:

the implantable medical system capturing additional cardiac signal data using one or more other sensing vectors;

analyzing data related to the captured additional cardiac signal data and;

determining that an identified sensing vector is suitable for cardiac event detection;

determining that there is a best available sensing vector;

or

using the programmer to request operator input to complete a sensing vector selection process.

3. The method of claim 2, wherein the analyzing and determining steps are performed by the programmer, the method also comprising the implantable medical system transmitting data to the programmer for performing the analyzing and determining steps.

4. The method of claim 2, wherein the analyzing and determining steps are performed by the implantable medical system.

5. The method of claim 4, wherein the implantable medical system performs the capturing, analyzing and determining steps periodically.

6. The method of claim 4, wherein the implantable medical system performs the capturing, analyzing and determining steps occasionally.

7. The method of claim 4, wherein the implantable medical system performs the capturing, analyzing and determining steps in response to a request from the programmer.

8. The method of claim 1, wherein the implantable medical system includes signal processing circuitry having at least a first dynamic range and a second dynamic range, wherein, if the identified sensing vector is suitable for cardiac event detection, a dynamic range is selected.

9. A programmer for use with an implantable medical device system, the implantable medical device system including electrodes for sensing cardiac signals, the programmer comprising telemetry circuitry for communicating with the implantable medical device system, a user interface for communicating with an operator, and operational circuitry configured to perform a method of selecting a sensing vector for the implantable medical device system, the method comprising:

a) directing the implantable medical device system to capture and transmit data related to a selected sensing vector;

b) analyzing the transmitted data to determine if the selected sensing vector is well-suited for cardiac event detection;

if the selected sensing vector is well suited for cardiac event detection, directing the implantable medical device system to use the selected sensing vector for cardiac event detection;

or

repeating steps a) and b) with another sensing vector.

10. The programmer of claim 9, wherein the operational circuitry is further configured to perform the steps of:

if a second sensing vector is well suited for cardiac event detection, directing the implantable medical device system to use the second sensing vector for cardiac event detection;

or

repeating steps a) and b) with a yet another sensing vector;

if a third sensing vector is well suited for cardiac event detection, directing the implantable medical device system to use the third sensing vector for cardiac event detection;

or

x) identifying the best of the sensing vectors and directing the implantable medical device system to use the best sensing vector for cardiac event detection.

11. The programmer of claim 10, wherein the operational circuitry is further configured to perform the steps of identifying an appropriate dynamic range for the implantable medical device system and directing the implantable medical device system to use the identified dynamic range.

12. The programmer of claim 10, wherein the operational circuitry is adapted such that:

steps a) and b) allow for determination of at least an actual score or multiple possible scores, the multiple possible scores being determined when analysis reveals a likely ambiguity, each possible score corresponding to an outcome of the ambiguity; and

step x) includes;

identifying a set of available scores including any scores and possible scores determined when steps a) and b) were performed;

y) selecting a best available score from the set of available scores and;

if the best available score is an actual score, identifying a corresponding sensing vector as the best of the sensing vectors;

if the best available score is a possible score, requesting user input to eliminate the likely ambiguity, determining whether the user input verifies an outcome corresponding to the possible score and, if so, identifying a corresponding sensing vector as the best of the sensing vectors, or, if not, removing the possible score from the set of available scores and returning to step y).

13. The programmer of claim 12, wherein the operational circuitry is adapted such that:

steps a) and b) also allow for a determination that a vector is unsuitable for cardiac event detection, and, if a particular vector is determined to be unsuitable for cardiac event detection, that vector is not considered in step x).

14. The programmer of claim 9, wherein the operational circuitry is adapted such that steps a) and b) include calculating either a score or, if ambiguity is likely, multiple possible scores for the selected sensing vector and the selected sensing vector is well-suited for cardiac event detection if a score is calculated and the score exceeds a threshold for the selected sensing vector.

15. The programmer of claim 14, wherein the operational circuitry is adapted such that, if steps a) and b) are repeated for multiple sensing vectors, the threshold is adapted to each of the sensing vectors.

16. The programmer of claim 9, wherein the operational circuitry comprises readable memory encoding an instruction set for performing the method of selecting a sensing vector.

17. An implantable medical device system including electrodes for sensing cardiac signals and operational circuitry coupled to the electrodes, the system adapted to define a plurality of sensing vectors for observing electrical activity of a patient'"'"'s heart from implanted positions, the operational circuitry configured to perform a method of selecting a sensing vector for the implantable medical device system, the method comprising:

a) capturing data related to a selected sensing vector;

b) analyzing the captured data to determine if the selected sensing vector is well-suited for cardiac event detection;

if the selected sensing vector is well suited for cardiac event detection, using the selected sensing vector for cardiac event detection;

or

repeating steps a) and b) with another sensing vector.

18. The implantable medical device system of claim 17, wherein the operational circuitry is further configured to perform the steps of:

if a second sensing vector is well suited for cardiac event detection, using the second sensing vector for cardiac event detection;

or

repeating steps a) and b) with a yet another sensing vector; and

if a third sensing vector is well suited for cardiac event detection, using the third sensing vector for cardiac event detection;

or

x) identifying the best of the sensing vectors and using the best sensing vector for cardiac event detection.

19. The implantable medical device system of claim 18, further comprising telemetry circuitry for communicating with a programmer having a user interface, wherein the operational circuitry is adapted such that:

steps a) and b) allow for determination of at least an actual score or multiple possible scores, the multiple possible scores being determined when analysis reveals a likely ambiguity, each possible score corresponding to an outcome of the ambiguity; and

step x) includes;

identifying a set of available scores including any scores and possible scores determined when steps a) and b) were performed;

y) selecting a best available score from the set of available scores and;

if the best available score is an actual score, identifying a corresponding sensing vector as the best of the sensing vectors;

if the best available score is a possible score, using the telemetry circuitry to direct the programmer to request user input to eliminate the likely ambiguity, receiving a response from the programmer indicating the user input, determining whether the user input verifies an outcome corresponding to the possible score and, if so, identifying a corresponding sensing vector as the best of the sensing vectors, or, if not, removing the possible score from the set of available scores and returning to step y).

20. The implantable medical device system of claim 19, wherein the operational circuitry is adapted such that:

steps a) and b) also allow for a determination that a vector is unsuitable for cardiac event detection, and, if a particular vector is determined to be unsuitable for cardiac event detection, that vector is not considered in step x).

21. The implantable medical device system of claim 17, wherein the operational circuitry is adapted such that steps a) and b) include calculating either a score or, if ambiguity is likely, multiple possible scores for the selected sensing vector and the selected sensing vector is well-suited for cardiac event detection if a score is calculated and the score exceeds a threshold for the selected sensing vector.

22. The implantable medical device system of claim 21, wherein the operational circuitry is adapted such that, if steps a) and b) are repeated for multiple sensing vectors, the threshold is adapted to each of the sensing vectors.

23. The implantable medical device system of claim 17, wherein the operational circuitry comprises readable memory encoding an instruction set for performing the method of selecting a sensing vector.

24. A method of cardiac signal analysis in an implantable cardiac stimulus system having at least first and second sensing electrodes defining a first sensing vector therebetween, the method comprising:

selecting a detection threshold;

capturing a plurality of detected events in which an electrical signal sensed along the first sensing vector exceeds the detection threshold;

analyzing at least one metric related to a signal to noise ratio and amplitude for the plurality of detected events; and

determining whether the first sensing vector is;

suitable for cardiac event detection;

unsuitable for cardiac event detection;

or

available for cardiac event detection.