IMPLANTABLE LEAD FUNCTIONAL STATUS MONITOR AND METHOD

• US 20100324629A1
• Filed: 08/26/2010
• Published: 12/23/2010
• Est. Priority Date: 01/19/1999
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: McVenes, Rick D., Wahistrand, John D., Peck, Bradley C., Jorgenson, David J., Trautmann, Charles D., Starkson, Ross O.
• Granted Patent: US 8,463,382 B2
• Time in Patent Office: Days
• US Class Current: 607/63
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

A system for monitoring trends in lead impedance includes collecting data from various sources in an implantable medical device system. Lead impedance, non-physiologic sensed events percentage of time in mode switch, results of capture management operation, sensed events, adversion pace counts, refractory sense counts and similar data are used to determine the status of a lead. A set of weighted sum rules are implemented by a software system to process the data and provide displayable information to health care professionals via a programmer. The lead monitoring system includes a patient alert system for patients to seek help in the event a serious lead condition is identified.

Claims

1. A method comprising:

measuring a parameter along a first electrical pathway of a lead;

measuring a parameter along a second electrical pathway of the lead; and

identifying the presence of a lead-related condition based on the parameter measured along the first electrical pathway and the parameter measured along the second electrical pathway.

2. The method of claim 1, wherein

measuring the parameter along the first electrical pathway comprises measuring an impedance along a unipolar electrical pathway;

measuring the parameter along the second electrical pathway comprises measuring an impedance along a bipolar electrical pathway; and

identifying the presence of a lead-related condition based on the impedance along the unipolar electrical pathway and the impedance along the bipolar electrical pathway.

3. The method of claim 2, wherein identifying the presence of the lead-related condition based on the impedance along the unipolar electrical pathway and the impedance along the bipolar electrical pathway comprises:

comparing impedances measured along the unipolar electrical pathway with impedances measured along the bipolar electrical pathway; and

identifying the presence of the lead-related condition based on the comparison.

4. The method of claim 3, wherein identifying the presence of the lead-related condition based on the comparison comprises identifying the presence of the lead-related when a drop of more than fifty ohms is detected on the bipolar electrical pathway as compared to the unipolar electrical pathway.

5. The method of claim 4, further comprising determining that the lead-related condition is a break in the bipolar insulation when the drop of more than fifty ohms is detected on the bipolar electrical pathway as compared to the unipolar electrical pathway.

6. The method of claim 2, wherein measuring the impedance comprises measuring the impedance using one or more subthreshold pulses.

7. The method of claim 1, wherein measuring the parameter along the first electrical pathway comprises sensing signals along a first sensing pathway formed by one or more of a plurality of electrodes;

measuring the parameter along the first electrical pathway comprises sensing signals along a second sensing pathway, different from the first sensing pathway, formed by one or more of the plurality of electrodes;

identifying the presence of a lead-related condition based on the sensed signals along the first and second sensing pathways.

8. The method of claim 7, wherein identifying the presence of a lead-related condition based on the sensed signals along the first and second sensing pathways comprises:

determining whether a number of non-physiologic sensed events occurring along the first sensing pathway is greater than a first threshold associated with the first sensing pathway to generate a first event count;

determining whether a number of non-physiologic sensed events occurring along the second sensing pathway is greater than a second threshold associated with the second sensing pathway to generate a second event count; and

identifying the presence of a lead-related condition based on the first event count and the second event count.

9. The method of claim 8, wherein the first sensing pathway corresponds to a unipolar sensing pathway and the second sensing pathway corresponds to a bipolar sensing pathway.

10. The method of claim 8, further comprising:

determining a number of counter windows; and

determining whether a sum of the first event count and the second event count is greater than a count threshold, wherein the count threshold varies depending on the determined number of counter windows.

11. A medical device system comprising:

a lead having a plurality of electrodes; and

an implantable medical device coupled to lead and having a control circuit that measures a parameter along a first electrical pathway of the lead, measures a parameter along a second electrical pathway of the lead, and identifies the presence of a lead-related condition based on the parameter measured along the first electrical pathway and the parameter measured along the second electrical pathway.

12. The system of claim 11, wherein the control circuit measures an impedance along a unipolar electrical pathway, measures an impedance along a bipolar electrical pathway, and identifies the presence of a lead-related condition based on the impedance along the unipolar electrical pathway and the impedance along the bipolar electrical pathway.

13. The system of claim 12, wherein the control circuit compares impedances measured along the unipolar electrical pathway with impedances measured along the bipolar electrical pathway and identifies the presence of the lead-related condition based on the comparison.

14. The system of claim 13, wherein the control circuit identifies the presence of the lead-related when a drop of more than fifty ohms is detected on the bipolar electrical pathway as compared to the unipolar electrical pathway.

15. The system of claim 14, wherein the control circuit determines that the lead-related condition is a break in the bipolar insulation when the drop of more than fifty ohms is detected on the bipolar electrical pathway as compared to the unipolar electrical pathway.

16. The system of claim 12, wherein the control circuit measures the impedance using one or more subthreshold pulses.

17. The system of claim 11, wherein the control circuit senses signals along a first sensing pathway formed by one or more of the plurality of electrodes, senses signals along a second sensing pathway, different from the first sensing pathway, formed by one or more of the plurality of electrodes, and identifies the presence of a lead-related condition based on the sensed signals along the first and second sensing pathways.

18. The system of claim 17, wherein the control circuit determines whether a number of non-physiologic sensed events occurring along the first sensing pathway is greater than a first threshold associated with the first sensing pathway to generate a first event count, determines whether a number of non-physiologic sensed events occurring along the second sensing pathway is greater than a second threshold associated with the second sensing pathway to generate a second event count, and identifies the presence of a lead-related condition based on the first event count and the second event count.

19. The system of claim 18, wherein the first sensing pathway corresponds to a unipolar sensing pathway and the second sensing pathway corresponds to a bipolar sensing pathway.

20. The system of claim 18, wherein the control circuit determines a number of counter windows and identifies the presence of a lead-related condition when a sum of the first event count and the second event count is greater than a count threshold, wherein the count threshold varies depending on the determined number of counter windows.