SYSTEM AND METHOD FOR DETERMINING ELECTRODE-TISSUE CONTACT USING PHASE DIFFERENCE

• US 20080312521A1
• Filed: 06/14/2007
• Published: 12/18/2008
• Est. Priority Date: 06/14/2007
• Status: Abandoned Application

• Current Assignee: Hansen Medical Incorporated (Johnson & Johnson)
• Original Assignee: Hansen Medical Incorporated (Johnson & Johnson)
• Inventors: Solomon, Edward G.
• Application Number:
  US11/762,779
• Publication Number:
  US 20080312521A1
• Time in Patent Office: Days
• US Class Current: 600/374
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter

Abstract

Methods and systems for monitoring contact between a medical probe and tissue are provided. A medical probe is introduced into a patient adjacent the tissue. A time varying signal is transmitted to or from the second electrode, the time varying signal is sensed at the first tip electrode, a phase difference between the transmitted signal and the sensed signal is determined, and contact between the first tip electrode and the tissue is detected based on the determined phase difference.

Claims

1. A method of monitoring contact between a medical probe and tissue, the medical probe having a first tip electrode and a second electrode proximal to the first tip electrode, comprising:

introducing the medical probe into a patient adjacent the tissue;

transmitting a time varying signal to or from the second electrode;

sensing the time varying signal at the first tip electrode;

determining a phase difference between the transmitted signal and the sensed signal; and

detecting contact between the first tip electrode and the tissue based on the determined phase difference.

2. The method of claim 1, wherein the tissue is heart tissue.

3. The method of claim 1, wherein the medical probe is an intravascular catheter.

4. The method of claim 1, wherein the second electrode is a ring electrode.

5. The method of claim 1, wherein the contact detection comprises comparing the phase difference to a threshold, and determining that the medical probe is in contact with the tissue if the phase difference exceeds the threshold.

6. The method of claim 1, wherein the contact detection comprises determining an extent of the contact based on the phase difference.

7. The method of claim 1, wherein the medical probe further has a third electrode proximal to the first tip electrode, the method further comprising determining another phase difference between the second electrode and the third electrode, wherein the contact detection is further based on the other determined phase difference.

8. The method of claim 1, further comprising performing a medical procedure on the tissue when the contact between the medical probe and the tissue has been detected.

9-14. -14. (canceled)

15. A medical system, comprising:

a medical probe having a first tip electrode and a second electrode proximal to the first tip electrode; and

a tissue contact monitoring device configured for transmitting a time varying signal to or from the second electrode, sensing the time varying signal at the first tip electrode, determining a phase difference between the transmitted signal and the sensed signal at the first tip electrode, and conveying an output to a user indicative of contact between the first tip electrode and the tissue, the output being based on the determined phase difference.

16. The system of claim 15, wherein the medical probe is an intravascular catheter.

17. The system of claim 15, wherein the second electrode is ring electrode.

18. The system of claim 15, wherein the monitoring device is configured for comparing the phase difference to a threshold, and determining that the medical probe is in contact with the tissue if the phase difference exceeds the threshold.

19. The system of claim 15, wherein the monitoring device is configured for determining an extent of the contact based on the phase difference.

20. The system of claim 15, wherein the output is a visual display of the phase difference.

21. The system of claim 15, wherein the medical probe has a third electrode proximal to the first tip electrode, and the monitoring device is further configured for sensing the time varying signal at the third electrode, determining another phase difference between transmitted signal and the sensed signal at the third electrode, wherein the contact detection is further based on the other determined phase difference.

22. The system of claim 15, further comprising a radio frequency (RF) generator configured for delivering ablation energy to the first tip electrode.

23. A tissue contact monitoring device, comprising:

an electrical terminal configured for coupling to a medical probe having a first tip electrode and a second electrode proximal to the first tip electrode; and

a processor configured for transmitting a time varying signal to or from the second electrode, sensing the time varying signal at the first tip electrode, and determining a phase difference between the transmitted signal and the sensed signal at the first tip electrode; and

a user interface configured for conveying an output indicative of contact between the first tip electrode and the tissue, the output being based on the determined phase difference.

24. The monitoring device of claim 23, wherein the processor is configured for comparing the phase difference to a threshold, and determining that the medical probe is in contact with the tissue if the phase difference exceeds the threshold.

25. The monitoring device of claim 23, wherein the processor is configured for determining an extent of the contact based on the phase difference.

26. The monitoring device of claim 23, wherein the user interface comprises a video monitor, and the output is a visual display of the phase difference.

27. The monitoring device of claim 23, wherein the monitoring device is further configured for sensing the time varying signal at the third electrode, and determining another phase difference between the transmitted signal and the sensed signal at the third electrode, wherein the contact detection is further based on the other determined phase difference.