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

• US 7,369,893 B2
• Filed: 04/27/2005
• Issued: 05/06/2008
• 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.
• Primary Examiner(s): Layno; Carl
• Assistant Examiner(s): LEE, YUN HAENG NMN
• Application Number:
  US11/115,607
• Publication Number:
  US 20060116733A1
• Time in Patent Office: 1,105 Days
• Field of Search: 607/27, 607/28
• 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, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition;

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

controlling delivery of therapy in response to the lead-related condition and oversensing being present, 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 oversensing criteria and the impedance criteria being satisfied, 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.

2. The method of claim 1, 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.

3. The method of claim 1, 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.

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

determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition;

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

controlling delivery of therapy in response to the lead-related condition and oversensing being present, 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 oversensing criteria and the impedance criteria being satisfied, 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.

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

determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition;

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

controlling delivery of therapy in response to the lead-related condition and oversensing being present, 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 oversensing criteria and the impedance criteria being satisfied, 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.

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

determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition;

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

controlling delivery of therapy in response to the lead-related condition and oversensing being present, 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 oversensing criteria and the impedance criteria being satisfied, 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.

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

determining, prior to detection of a cardiac event requiring the delivered therapy, the presence of a lead-related condition;

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

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

8. The method of claim 7, 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.

9. The method of claim 8, 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.

10. The method of claim 8, 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.

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

determining, prior to determining the presence of an episode event, whether a first oversensing criteria, a second oversensing criteria, and 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.

12. The method of claim 11, 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.

13. The method of claim 11, 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.

14. The method of claim 11, 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.

15. The method of claim 11, 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.

16. The method of claim 11, 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.

17. The method of claim 11, 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.

18. The method of claim 11, 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.

19. The method of claim 18, 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.

20. The method of claim 18, 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.