Method and apparatus for identifying lead-related conditions using prediction and detection criteria

• US 20060116733A1
• Filed: 04/27/2005
• Published: 06/01/2006
• Est. Priority Date: 12/01/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Gunderson, Bruce D.
• Granted Patent: US 7,369,893 B2
• Time in Patent Office: Days
• US Class Current: 607/27
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

A method for delivering therapy in a medical device that includes a two-tiered approach of determining the presence of a lead-related condition, and determining, in response to a lead-related condition being present, the presence of oversensing. Deliver of therapy by the medical device is controlled in response to determining that both the lead-related condition and oversensing are present.

Claims

1. A method for delivering therapy in a medical device, comprising:

determining the presence of a lead-related condition;

determining, in response to a lead-related condition being present, the presence of oversensing; and

controlling deliver of therapy in response to the lead-related condition and oversensing being present.

2. The method of claim 1, further comprising generating an alert in response to determining that a lead-related condition is present.

3. The method of claim 1, wherein determining the presence of a lead-related condition comprises:

determining whether a first oversensing criteria is satisfied;

determining whether a second oversensing criteria is satisfied;

determining whether an impedance criteria has been satisfied; and

generating an alert in response to more than one of the first oversensing criteria, the second over sensing criteria and the impedance criteria being satisfied.

4. The method of claim 3, wherein determining whether a first oversensing criteria is satisfied comprises:

determining whether a predetermined number of RR-intervals are within a first predetermined time period subsequent to a blanking period associated with a sensing device; and

determining whether the predetermined number of RR-intervals occur within a second predetermined time period.

5. The method of claim 3, wherein determining whether a first oversensing criteria is satisfied comprises:

determining a number of RR-intervals that are within a first predetermined time period subsequent to a blanking period associated with a sensing device; and

determining whether the number of RR-intervals within the first predetermined time period is greater than a predetermined threshold.

6. The method of claim 3, wherein determining whether a first oversensing criteria is satisfied comprises:

determining whether a time duration window is greater than a threshold time period; and

determining, in response to the time duration window not being greater than the threshold time period, a ratio of RR-intervals that are within a first predetermined time period subsequent to a blanking period associated with a sensing device.

7. The method of claim 3, wherein determining whether a second oversensing criteria is satisfied comprises determining whether there are a predetermined number of events having average cycle lengths that are less than a predetermined threshold occurring within a predetermined time period.

8. The method of claim 3, wherein determining whether an impedance criteria has been satisfied comprises:

measuring a lead impedance;

determining a short-term impedance trend;

determining a long-term impedance trend; and

applying a set of diagnostic criteria to the short-term and long-term impedance trends.

9. The method of claim 3, wherein determining whether a first oversensing criteria is satisfied comprises:

determining, during a first time period, whether a predetermined number of RR-intervals are within a second predetermined time period subsequent to a blanking period associated with a sensing device;

determining, during a third time period subsequent to the first time period, a ratio of RR-intervals that are within the second predetermined time period subsequent; and

determining, during a fourth time period subsequent to the second time period, whether the number of RR-intervals within the second predetermined time period is greater than a predetermined threshold.

10. The method of claim 1, wherein determining, in response to a lead-related condition being present, the presence of oversensing comprises:

sensing cardiac signals and detecting cardiac events via a first electrode configuration;

determining the presence of an episode event in response to the detected cardiac events;

sensing the cardiac signals via a second electrode configuration;

determining predetermined values associated with cardiac signals sensed via the second electrode configuration corresponding to the event episode; and

controlling delivery of therapy in response to the determined values.

11. The method of claim 10, wherein determining predetermined values comprises:

determining voltage values of a predetermined number of samples located within a window defined about the cardiac signals sensed via the second electrode configuration;

determining a sample maximum voltage value and a sample minimum voltage value corresponding to the predetermined number of samples; and

comparing the sample maximum voltage value and the sample minimum voltage value to generate sample amplitudes.

12. The method of claim 11, wherein controlling delivery of therapy comprises:

determining a maximum amplitude and a minimum amplitude corresponding to a predetermined number of the generated sample amplitudes;

determining whether the maximum amplitude is greater than a maximum amplitude threshold and the minimum amplitude is less than a first minimum amplitude threshold; and

determining whether the minimum amplitude is less than a second minimum amplitude threshold.

13. The method of claim 11, wherein controlling delivery of therapy comprises:

determining a maximum amplitude and a minimum amplitude corresponding to a predetermined number of the generated sample amplitudes; and

comparing the maximum amplitude and the minimum amplitude.

14. A method for delivering therapy in a medical device, comprising:

determining whether a first oversensing criteria is satisfied;

determining whether a second oversensing criteria is satisfied;

determining whether an impedance criteria has been satisfied;

generating an alert in response to more than one of the first oversensing criteria, the second over sensing criteria and the impedance criteria being satisfied;

sensing cardiac signals and detecting cardiac events via a first electrode configuration in response to more than one of the first oversensing criteria, the second over sensing criteria and the impedance criteria being satisfied;

determining the presence of an episode event in response to the detected cardiac events;

sensing the cardiac signals via a second electrode configuration;

determining predetermined values associated with cardiac signals sensed via the second electrode configuration corresponding to the event episode; and

controlling delivery of therapy in response to the determined values.

15. The method of claim 14, wherein determining whether a first oversensing criteria is satisfied comprises:

determining whether a predetermined number of RR-intervals are within a first predetermined time period subsequent to a blanking period associated with a sensing device; and

determining whether the predetermined number of RR-intervals occur within a second predetermined time period.

16. The method of claim 14, wherein determining whether a first oversensing criteria is satisfied comprises:

determining a number of RR-intervals that are within a first predetermined time period subsequent to a blanking period associated with a sensing device; and

determining whether the number of RR-intervals within the first predetermined time period is greater than a predetermined threshold.

17. The method of claim 14, wherein determining whether a first oversensing criteria is satisfied comprises:

determining whether a time duration window is greater than a threshold time period; and

determining, in response to the time duration window not being greater than the threshold time period, a ratio of RR-intervals that are within a first predetermined time period subsequent to a blanking period associated with a sensing device.

18. The method of claim 14, wherein determining whether a second oversensing criteria is satisfied comprises determining whether there are a predetermined number of events having average cycle lengths that are less than a predetermined threshold occurring within a predetermined time period.

19. The method of claim 14, wherein determining whether an impedance criteria has been satisfied comprises:

measuring a lead impedance;

determining a short-term impedance trend;

determining a long-term impedance trend; and

applying a set of diagnostic criteria to the short-term and long-term impedance trends.

20. The method of claim 14, wherein determining whether a first oversensing criteria is satisfied comprises:

determining, during a first time period, whether a predetermined number of RR-intervals are within a second predetermined time period subsequent to a blanking period associated with a sensing device;

determining, during a third time period subsequent to the first time period, a ratio of RR-intervals that are within the second predetermined time period subsequent; and

determining, during a fourth time period subsequent to the second time period, whether the number of RR-intervals within the second predetermined time period is greater than a predetermined threshold.

21. The method of claim 14, wherein determining predetermined values comprises:

determining voltage values of a predetermined number of samples located within a window defined about the cardiac signals sensed via the second electrode configuration;

determining a sample maximum voltage value and a sample minimum voltage value corresponding to the predetermined number of samples; and

comparing the sample maximum voltage value and the sample minimum voltage value to generate sample amplitudes.

22. The method of claim 21, wherein controlling delivery of therapy comprises:

determining a maximum amplitude and a minimum amplitude corresponding to a predetermined number of the generated sample amplitudes;

determining whether the maximum amplitude is greater than a maximum amplitude threshold and the minimum amplitude is less than a first minimum amplitude threshold; and

determining whether the minimum amplitude is less than a second minimum amplitude threshold.

23. The method of claim 21, wherein controlling delivery of therapy comprises:

determining a maximum amplitude and a minimum amplitude corresponding to a predetermined number of the generated sample amplitudes; and

comparing the maximum amplitude and the minimum amplitude.