Apparatus and method for detecting micro-dislodgment of a pacing lead

• US 6,445,952 B1
• Filed: 05/18/2000
• Issued: 09/03/2002
• Est. Priority Date: 05/18/2000
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Manrodt, Christopher M., Markowitz, H. Toby, Peck, Bradley C.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US09/573,507
• Time in Patent Office: 838 Days
• Field of Search: 607/28, 607/27, 607/2, 607/63, 600/547
• US Class Current: 607/28
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/37241 providing test stimulations

Abstract

An apparatus and method for detecting micro-dislodgment at a heart tissue/pacing lead electrode interface involves measuring a first pacing threshold parameter at a first time in a patient'"'"'s cardiac cycle and measuring a second pacing threshold parameter at a second time in the patient'"'"'s cardiac cycle. Micro-dislodgment occurring at the heart tissue/pacing lead electrode interface is detected using the first and second pacing threshold parameters. Micro-dislodgment may be detected by comparing a difference between, or a ratio of, the first and second pacing threshold parameters to a preestablished maximum allowable deviation value. A difference between the first and second pacing threshold parameters or a ratio in excess of the preestablished maximum allowable deviation value indicates a problem at the heart tissue/pacing lead interface. The first and second pacing threshold parameters are preferably pacing threshold voltages, and the preestablished maximum allowable deviation value is either a voltage ranging from about 0.2 volts to about 2 volts or a percentage ranging from about 5% to about 100%. The micro-dislodgment procedure may be performed in-situ an implantable pulse generator (IPG), with data indicative of a detected change at the heart tissue/pacing electrode interface being stored in a memory coupled to the IPG and subsequently read out of memory for evaluation. Alternatively, the micro-dislodgment procedure may be performed using an external programmer and may further be performed during implantation of a pacing lead electrode at the heart tissue/pacing lead electrode interface to assure a physician of proper lead attachment.

Claims

1. A method of detecting micro-dislodgment at a heart tissue/pacing lead electrode interface, comprising:

measuring a first pacing threshold parameter at a first time in a patient'"'"'s cardiac cycle;

measuring a second pacing threshold parameter at a second time in the patient'"'"'s cardiac cycle, the second time being different from the first time; and

detecting micro-dislodgment at the heart tissue/pacing lead electrode interface using the first and second pacing threshold parameters.

2. The method of claim 1, wherein each of the first and second pacing threshold parameters is a pacing threshold voltage.

3. The method of claim 1, wherein each of the first and second pacing threshold parameters is a pacing threshold pulse width.

4. The method of claim 1, wherein detecting micro-dislodgment comprises comparing a difference between the first pacing threshold parameter and the second pacing threshold parameter to a preestablished maximum allowable deviation value.

5. The method of claim 4, wherein the preestablished maximum allowable deviation value is a voltage ranging from about 0.2 volts to about 2 volts.

6. The method of claim 1, wherein detecting micro-dislodgment comprises computing a ratio of the first pacing threshold parameter relative to the second pacing threshold parameter and comparing the computed ratio to a preestablished maximum allowable deviation value.

7. The method of claim 6, wherein the preestablished maximum allowable deviation value is a percentage ranging from about 5% to about 50%.

8. The method of claim 1, wherein:

measuring the first pacing threshold parameter comprises measuring the first pacing threshold parameter after initiation of an atrial contraction but prior to any appreciable amount of ventricular contraction; and

measuring the second pacing threshold parameter comprises measuring the second pacing threshold parameter after initiation of an atrial contraction and after an appreciable amount of ventricular contraction.

9. The method of claim 1, wherein:

measuring the first pacing threshold parameter comprises measuring the first pacing threshold parameter after a delay of up to about 110 ms subsequent to initiation of an atrial contraction; and

measuring the second pacing threshold parameter comprises measuring the second pacing threshold parameter after a delay of about 100 ms to about 400 ms subsequent to initiation of an atrial contraction.

10. The method of claim 1, further comprising performing the respective measuring steps and the detecting step using an external programmer and an implantable medical device.

11. The method of claim 1, further comprising performing the respective measuring steps and the detecting step during implantation of a pacing lead electrode at the heart tissue/pacing lead electrode interface.

12. The method of claim 1, further comprising performing the respective measuring steps and the detecting step solely by use of an implantable medical device comprising a pulse generator.

13. The method of claim 1, further comprising performing the respective measuring steps and the detecting step using an implantable medical device while the patient of ambulatory.

14. The method of claim 1, further comprising storing data indicative of the detected micro-dislodgment.

15. The method of claim 14, further comprising reading out the stored data indicative of the detected micro-dislodgment.

16. A method of detecting changes at a heart tissue/pacing lead electrode interface, comprising:

stimulating the right atrium to contract using an atrium pace signal or sensing a right atrium contraction;

measuring a first pacing threshold parameter in the right ventricle prior to any appreciable contracting of the right ventricle;

repeating stimulating the right atrium to contract using an atrium pace signal or sensing a right atrium contraction;

measuring a second pacing threshold parameter in the right ventricle during appreciable contracting of the right ventricular; and

determining a change at the heart tissue/pacing lead electrode interface using the first and second pacing threshold parameters.

17. The method of claim 16, wherein each of the first and second pacing threshold parameters is a pacing threshold voltage.

18. The method of claim 16, wherein each of the first and second pacing threshold parameters is a pacing threshold pulse width.

19. The method of claim 16, wherein:

measuring the first pacing threshold parameter comprises measuring the first pacing threshold parameter subsequent to a first delay period of up to about 110 ms following the right atrium contraction; and

measuring the second pacing threshold parameter comprises measuring the second pacing threshold parameter subsequent to a second delay period of about 100 ms to about 400 ms following the right atrium contraction.

20. The method of claim 16, wherein detecting micro-dislodgment comprises comparing a difference between the first pacing threshold parameter and the second pacing threshold parameter to a preestablished maximum allowable deviation value.

21. The method of claim 20, wherein the preestablished maximum allowable deviation value is a voltage ranging from about 0.2 volts to about 2 volts.

22. The method of claim 16, wherein detecting micro-dislodgment comprises computing a ratio of the first pacing threshold parameter relative to the second pacing threshold parameter and comparing the computed ratio to a preestablished maximum allowable deviation value.

23. The method of claim 22, wherein the preestablished maximum allowable deviation value is a percentage ranging from about 5% to about 50%.

24. The method of claim 16, further comprising performing the respective measuring steps and the detecting step using an external programmer and an implantable medical device.

25. The method of claim 16, further comprising performing the respective measuring steps and the detecting step during implantation of a pacing lead electrode at the heart tissue/pacing lead electrode interface.

26. The method of claim 16, further comprising performing the respective measuring steps and the detecting step solely by use of an implantable medical device comprising a pulse generator.

27. The method of claim 16, further comprising performing the respective measuring steps and the detecting step using an implantable medical device while the patient of ambulatory.

28. The method of claim 16, further comprising storing data indicative of the detected change at the heart tissue/pacing lead electrode interface.

29. The method of claim 28, further comprising reading out the stored data indicative of the detected change at the heart tissue/pacing lead electrode interface.

30. An apparatus for detecting micro-dislodgment at a heart tissue/pacing lead electrode interface, comprising:

an implantable medical device including a pulse generator;

a first pacing lead comprising a first electrode adapted for implantation in a right atrium of a heart;

second pacing lead comprising a second electrode adapted for implantation in a right ventricle of the heart; and

a microprocessor that determines an occurrence of micro-dislodgment at the second electrode/right ventricle interface using a first pacing threshold parameter, determined for the right ventricle prior to any appreciable contracting of the right ventricle, and a second pacing threshold parameter, determined for the right ventricle during appreciable contracting of the right ventricular.

31. The apparatus of claim 30, wherein each of the first and second pacing threshold parameters is a pacing threshold voltage.

32. The apparatus of claim 30, wherein each of the first and second pacing threshold parameters is a pacing threshold pulse width.

33. The apparatus of claim 30, wherein:

the microprocessor determines the first pacing threshold by determining the first pacing threshold parameter subsequent to a first delay period of up to about 110 ms following a right atrium contraction; and

the microprocessor determines the second pacing threshold parameter by determining the second pacing threshold parameter subsequent to a second delay period of about 100 ms to about 400 ms following the right atrium contraction.

34. The apparatus of claim 30, wherein the microprocessor determines the occurrence of micro-dislodgment by comparing a difference between the first pacing threshold parameter and the second pacing threshold parameter to a preestablished maximum allowable deviation value.

35. The apparatus of claim 34, wherein the preestablished maximum allowable deviation value is a voltage ranging from about 0.2 volts to about 2 volts.

36. The apparatus of claim 30, wherein the microprocessor determines the occurrence of micro-dislodgment by computing a ratio of the first pacing threshold parameter relative to the second pacing threshold parameter and comparing the computed ratio to a preestablished maximum allowable deviation value.

37. The apparatus of claim 36, wherein the preestablished maximum allowable deviation value is a percentage ranging from about 5% to about 50%.

38. The apparatus of claim 30, wherein the microprocessor is provided in the implantable medical device.

39. The apparatus of claim 38, wherein the microprocessor stores data indicative of the detected occurrence of micro-dislodgment in a memory provided in the implantable medical device and coordinates transfer of the stored data from the memory to an external programmer.

40. The apparatus of claim 30, wherein the microprocessor is provided in an external programmer.