SYSTEM AND METHOD TO EVALUATE ELECTRODE POSITION AND SPACING

• US 20090093857A1
• Filed: 07/31/2008
• Published: 04/09/2009
• Est. Priority Date: 12/28/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hettrick, Douglas A., Sowelam, Sameh, Markowitz, H. Toby, Falkner, Phillip
• Granted Patent: US 7,941,213 B2
• Time in Patent Office: Days
• US Class Current: 607/11
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371

Abstract

An IMD can be implanted into a patient to address various conditions. The IMD case and leads can have various electrodes and other portions to measure various physiological conditions. For example, a selected current can be generated between two electrodes, either external or internal in the patient, and a voltage can be measured by one or more electrodes of the IMD. A voltage can be measured at two or more locations to determine a relative motion of different electrodes. If the electrodes are in different portions of the heart, a determination can be made of a relative motion or position of the heart or portions of the heart.

Claims

1. A system to determine a location of an electrode within a volume, comprising:

an implantable medical device operable to be positioned and contained within the volume, including;

a lead connected to a connector having a first implantable electrode;

an implantable case containing an electronics system operable to receive a signal from the first implantable electrode;

wherein the first electrode is operable to move within the volume relative to the implantable medical device;

a current injecting system operable to inject a current into the volume between a first injecting electrode and a second injecting electrode;

wherein the first implantable electrode is operable to sense a voltage at a location due at least in part to the injected current.

2. The system of claim 1, wherein the current injecting system includes:

a generator positioned exterior to the volume;

wherein the generator is operable to deliver the current into the volume with the first injecting electrode and the second injecting electrode;

wherein the first implantable electrode of the lead is operable to sense a voltage within the volume.

3. The system of claim 2, further comprising:

a third injecting electrode, a fourth injecting electrode, a fifth injecting electrode, and a sixth injecting electrode;

wherein two of each of the first, second, third, fourth, fifth and sixth injecting electrodes are paired to define three axes in the volume;

wherein the generator is operable to determine a period for injecting a current into the volume between each of the pairs of the injecting electrodes.

4. The system of claim 3, wherein the injected current has a frequency of about 1 kHz to about 10 kHz;

wherein the generator is operable to inject a current between the respective pairs of the injecting electrodes for about 10 cycles to about 200 cycles;

wherein after the selected number of cycles a current is injected with a different pair of the injecting electrodes from the previous pair of injecting electrodes.

5. The system of claim 3, further comprising:

a null period where no current is injected by the generator;

wherein the null period is operable to synchronize the current injecting system and the implantable medical device.

6. The system of claim 1, wherein the current injecting system includes:

a current source contained with the implantable medical device;

a second implantable electrode and a third implantable electrode;

wherein the third implantable electrode is a case of the implantable medical device;

wherein the current source is operable to inject a current using at least two of the first implantable electrode, the second implantable electrode, and the third implantable electrode;

wherein at least one of the first implantable electrode, the second implantable electrode, and the third implantable electrode is operable to sense a voltage due at least in part to the injected current.

7. The system of claim 6, wherein the implantable medical device further includes a processor operable to execute instructions to determine at least a relative position of a first sensed voltage and a second sensed voltage of at least one of the first implantable electrode, the second implantable electrode and the third implantable electrode due to the injected current.

8. The system of claim 7, wherein the processor is further operable to execute instructions to determine a pacing signal generated by the implantable medical device.

9. The system of claim 2, wherein the implantable medical device further includes an internal telemetry system;

wherein the internal telemetry system is operable to synchronize the signal received from the electrode and the current generated into the volume with the generator.

10. A system to measure a position of a surface of a portion of an anatomy, comprising:

an implantable medical device including;

a lead including a first electrode;

a position sensing system operable to sense a voltage at the first electrode; and

a processor operable to compare a first sensed voltage and a second sensed voltage at the first electrode; and

a current injecting system operable to inject a current into the anatomical system to generate the voltage sensed by the first electrode.

11. The system of claim 10, wherein the current injecting system is defined by the implantable medical device, wherein the implantable medical device further includes:

a second electrode and a third electrode;

a current source system operable to inject a current between at least the first electrode and the second electrode;

wherein the position system is operable to sense a voltage with at least the third electrode.

12. The system of claim 11 further comprising:

a fourth electrode;

wherein a voltage at one of the first, the second, third, and the fourth electrode is compared to a voltage sensed at another of the first electrode, the second electrode, the third electrode, or the fourth electrode;

wherein the processor is operable to execute instructions to determine a relative position of at least two of the first electrode, the second electrode, the third electrode, and the fourth electrode to identify a dimension of the anatomical system.

13. The system of claim 11, wherein at least one of the first electrode, the second electrode, and the third electrode is positioned within a heart in the anatomical system;

wherein the sensed voltage is operable to determine a position of at least a wall of the heart.

14. The system of claim 10, wherein the sensed voltage includes a first voltage at a first time and a second voltage at a second time;

wherein the processor is operable to execute instructions to determine a change in position between the first time and the second time.

15. The system of claim 14, wherein the change in position is determined to be at least one of a heart wall thickness, a left ventricle volume, a left ventricle dimension, a right ventricle volume, a right ventricle dimension, a stoke volume, or combinations thereof.

16. A system to determine a location of an electrode with a volume, comprising:

an implantable medical device operable to be positioned and contained within the volume, including;

an implantable case;

a lead connected to a connector associated with the implantable case having a first implantable electrode; and

a processor operable to execute a first set of instructions when a signal from the lead is received or a condition in the volume is sensed;

wherein the processor is operable to change the first set of instructions based upon the signal;

wherein the first electrode is operable to move within the volume; and

a current injecting system operable to inject a current into the volume between a first injecting electrode and a second injecting electrode;

wherein the first implantable electrode is operable to sense a voltage at a location due at least in part to the injected current.

17. The system of claim 16, wherein the current injecting system includes three pairs of injecting electrodes that are operable to define three substantially orthogonal axes of current within the volume;

and

wherein the implantable medical device further includes a telemetry system operable to transmit the voltage sensed at the location.

18. The system of claim 17, wherein the processor is operable to execute instructions to determine a position of the first implantable electrode based at least in part on the voltage sensed at the location;

wherein the determined position can be telemetrically transmitted from the implantable medical device.

19. The system of claim 18, further comprising:

an external processor system;

wherein the external processor system is operable to receive the telemetrically transmitted determined position;

wherein the external processor system is operable to determine a condition of an anatomical feature within the volume based upon the transmitted determined position.

20. The system of claim 19, further comprising:

a second implantable electrode;

wherein the first implantable electrode is operable to sense a voltage at a first location and a second implantable electrode is operable to sense a voltage at a second location;

wherein at least one of the processor or the external processor system is operable to determine a dimension between the first implantable electrode and the second implantable electrode at the respective locations.

21. The system of claim 20, wherein the dimension is determined to be at least one of a heart wall thickness, a left ventricle volume, a left ventricle dimension, a right ventricle volume, a right ventricle dimension, a stoke volume, or combinations thereof.

22. A method of measuring movement of an electrode within a volume, comprising:

providing an implantable device;

positioning a lead extending from the implantable device within the volume, the lead including a first electrode;

injecting a current in the volume;

sensing a voltage in the volume with the first electrode; and

transmitting the sensed voltage to an electronics system of the implantable device.

23. The method of claim 22, wherein sensing a voltage includes:

sensing a first voltage at a first time and sensing a second voltage at a second time;

determining a first position of the first electrode with the first sensed voltage; and

determining a second position of the first electrode with the second sensed voltage.

24. The method of claim 23, further comprising:

implanting the first electrode in a surface;

determining a first position of the surface with the determined first position of the first electrode; and

determining a second position of the surface with the determined second position of the first electrode.

25. The method of claim 23, further comprising:

providing a processor in the implantable device;

providing a pacing system operable to deliver a pacing signal based upon first instructions executed by the processor; and

executing second instructions with the processor based upon the determined first position and the determined second position to alter the pacing signal.

26. The method of claim 23, further comprising:

placing a second electrode;

determining a third position of the second electrode; and

determining a distance between at least one of the determined first position and the determined second position and the determined third position.

27. The method of claim 26, further comprising:

implanting a second lead having the second electrode.

28. The method of claim 26, wherein the distance between one of the first position, the second position, or the third position is a thickness of an anatomical structure.

29. The method of claim 23, further comprising:

providing a telemetry system in the implantable device;

telemetrically transmitting the sensed voltage to an external processor system; and

determining an anatomical definition based upon the transmitted sensed voltage.

30. The method of claim 22, further comprising:

generating the current to be injected into the volume with a generator that is external to the volume; and

synchronizing the external generation of the current from the generator with the sensing of the voltage with the first electrode.

31. The method of claim 30, wherein synchronizing the external generation includes telemetrically sending a synchronization signal between the external generator and the provided implantable medical device or sensing a null voltage period in a pattern of generating the current.

32. A system to measure a position of a surface of a portion of an anatomy, comprising:

an implantable medical device including;

a lead including a first electrode;

a position sensing system operable to sense a voltage at the first electrode;

a processor operable to compare a first sensed voltage and a second sensed voltage at the first electrode;

a first telemetry system operable to transmit and receive information regarding at least the first electrode; and

a current injecting system operable to inject a current into the anatomical system to generate the voltage sensed by the first electrode, including;

a first pair of injecting electrodes and a second pair of injecting electrodes.

a current source system operable to inject a current between the first pair of injecting electrodes and the second pair of injecting electrodes; and

a second telemetry system operable to communicate with the first telemetry system;

wherein the position sensing system is operable to sense a voltage with at least the first electrode;

wherein the positioning sensing system is operable to determine or the first telemetry system is operable to transmit a sensed voltage relating to only one of the first pair of injecting electrodes or the second pair of injecting electrodes.

33. The system of claim 32, wherein the implantable medical device further includes:

a second electrode;

wherein a voltage at the first electrode is compared to a voltage sensed at the second electrode;

wherein the processor is operable to execute instructions to determine a relative position of the first electrode and the second electrode, to identify a dimension of the anatomy.

34. The system of claim 32, wherein at least one of the first pair of injecting electrodes and the second pair of injecting electrodes are implanted within the anatomy with the implantable medical device.