SYSTEM AND METHOD FOR ASSESSING LESIONS IN TISSUE

• US 20100069921A1
• Filed: 11/20/2009
• Published: 03/18/2010
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: St. Jude Medical (Abbott Laboratories Incorporated)
• Original Assignee: St. Jude Medical (Abbott Laboratories Incorporated)
• Inventors: Teplitsky, Liare R., Paul, Saurav, Deno, Don Curtis, Miller, Stephan P.
• Granted Patent: US 8,403,925 B2
• Time in Patent Office: Days
• US Class Current: 606/130
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00648 using more than one sensed parameter
• CPC Class Codes: A61B 2018/00696 Controlled or regulated parameters
• CPC Class Codes: A61B 2018/00773 Sensed parameters
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00863 Fluid flow
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2090/065 for measuring contact or contact pressure

Abstract

A method and system for assessing lesion formation in tissue is provided. The system includes an electronic control unit (ECU). The ECU is configured to acquire values for first and second components of a complex impedance between the electrode and the tissue, and to calculate an index responsive to the first and second values. The ECU is further configured to process the ECI to assess lesion formation in the tissue.

Claims

1. A system for assessing the formation of lesions in a tissue in a body, comprising:

an electronic control unit (ECU) configured to

(i) acquire values for first and second components of a complex impedance between an electrode and said tissue and to calculate an index responsive to at least said acquired values; and

(ii) process said index to assess lesion formation in a particular area of said tissue.

2. The system of claim 1, wherein said ECU is configured to determine, based on said index, at least one of (i) whether said particular area of tissue has been changed as a result of the application of ablative energy to said particular area of tissue, and (ii) the extent to which said particular area of tissue has been changed as a result of the application of ablative energy to said particular area of tissue.

3. The system of claim 1, wherein said ECU is configured to process said index by being further configured to compare said index with one of a predetermined index threshold and predefined index range to assess lesion formation in said particular area of tissue.

4. The system of claim 1, wherein said ECU is configured to process said index by being further configured to calculate a change in the index between a previously calculated index and said calculated index over a predetermined period of time and a predetermined surface distance traveled by said electrode, and to assess lesion formation in said particular area of tissue based on said change in the index.

5. The system of claim 1, wherein said ECU is configured to process said index by being further configured to calculate a rate of change in the index between said calculated index and a previously calculated index over a predetermined period of time, and to assess lesion formation in said particular area of tissue based on said rate of change in the index.

6. The system of claim 1, wherein said ECU is configured to process said index by being further configured to:

(i) receive location coordinates corresponding to a location of said electrode within said body;

(ii) calculate a change in the index between a previously calculated index and said calculated index over a predetermined time interval;

(iii) calculate a change in said location coordinates; and

(iv) calculate an index rate by dividing said change in the index by said change in said location coordinates of said electrode.

7. The system of claim 6, wherein said ECU is further configured to compare said index rate with a predetermined index rate threshold to assess lesion formation in said particular area of tissue.

8. The system of claim 1, wherein said ECU is configured to process said index by being further configured to calculate a corrected index to account for a predetermined variable influencing said index calculation, and wherein said corrected index is calculated by increasing or decreasing said calculated index by a predetermined offset.

9. The system of claim 1, wherein said ECU is further configured to acquire values for a predetermined variable and to calculate said index responsive to at least said acquired values of said first and second components of said complex impedance and said predetermined variable, wherein said predetermined variable comprises at least one of a contact force applied by said electrode against said tissue, a contact pressure applied by said electrode against said tissue, a temperature of said tissue, a change in temperature of said tissue, trabeculation of said tissue, a saline flow rate, and a blood flow rate.

10. The system of claim 1, wherein said ECU is further configured to generate a signal representative of an indicator of one of (i) said particular area of tissue being changed or unchanged/insufficiently changed as a result of the application of ablative energy to said particular area of tissue, and (ii) an extent to which said particular area of tissue has been changed as a result of the application of ablative energy to said particular area of tissue.

11. The system of claim 10 further comprising a display monitor, said ECU further configured to control said display monitor to display said indicator represented by said signal.

12. The system of claim 10, wherein said ECU is further configured to transmit said generated signal to a controller for a robotics application.

13. The system of claim 1, wherein said ECU is further configured to generate an electroanatomical map of said tissue using said calculated index to display tissue characteristics.

14. The system of claim 13, wherein said ECU is responsive to a user input to allow a user to add a marker onto said map.

15. The system of claim 13, wherein said ECU is configured to automatically add a marker onto said map.

16. The system of claim 13, wherein said ECU is further configured to acquire location information corresponding to said electrode and to associate said calculated index with said location information, said ECU still further configured to generate said map and to display said tissue characteristics based on said calculated index and said corresponding location information.

17. An article of manufacture, comprising:

a computer-readable storage medium having a computer program encoded thereon for assessing the formation of lesions in a tissue in a body, said computer program including code that, when executed on a computer, causes the computer to performing the steps of;

(i) calculating an index responsive to values for first and second components of a complex impedance between an electrode and said tissue; and

(ii) processing said calculated index to assess lesion formation in a particular area of said tissue.

18. The article of manufacture of claim 17, wherein said computer program includes code that, when executed on a computer, causes the computer to perform the step of processing said calculated index to determine whether said particular area of tissue has been ablated.

19. The article of manufacture of claim 17, wherein said computer program includes code that, when executed on a computer, causes the computer to perform the step of generating an electroanatomical map of said tissue using said index to display tissue characteristics.

20. A method of assessing the formation of lesions in a tissue in a body, comprising:

acquiring values for first and second components of a complex impedance between an electrode and said tissue;

calculating an index responsive to at least said first and second components of said complex impedance; and

processing said calculated index to assess lesion formation in particular area of said tissue.

21. The method of claim 20, wherein said processing step includes comparing said calculated index with one of a predetermined index threshold and a predefined index range to assess lesion formation in said particular area of tissue.

22. The method of claim 20 wherein said processing step includes calculating a rate of change in the index between said calculated index and a previously calculated index over one of a predetermined period of time and a predetermined surface distance traveled by said electrode, and to assess lesion formation in said particular area of tissue based on said rate of change in the index.

23. The method of claim 20 wherein said processing step includes:

(i) receiving location coordinates corresponding to a location of said electrode within said body;

(ii) calculating a change in the index between a previously calculated index and said calculated index over a predetermined time interval;

(iii) calculating a change in said location coordinates; and

(iv) calculating an index rate by dividing said change in the index by said change in said location coordinates of said electrode.

24. The method of claim 20 further comprising:

acquiring a value for a predetermined variable comprising one of a contact force between said electrode and said tissue, a contact pressure between said electrode and said tissue, a tissue temperature, and trabeculation of said tissue; and

calculating said index responsive to said values of said first and second components of said complex impedance and said variable.

25. The method of claim 20 further comprising:

generating an electroanatomical map of said tissue; and

displaying on a display monitor tissue characteristics on said map using said index.

26. An automated catheter guidance system, comprising:

a catheter manipulator assembly;

a catheter associated with said catheter manipulator assembly, said catheter including an electrode associated therewith,

a controller configured to direct movement of said catheter manipulator assembly in response to an index calculated from first and second components of a complex impedance between said electrode and a tissue in a body.

27. The system of claim 26 wherein said catheter manipulator assembly is a robotic catheter manipulator assembly including a robotic catheter device cartridge.

28. The system of claim 26 wherein said catheter further comprises a magnetic element, and said automated catheter manipulator assembly comprises a magnetic field generator configured to generate a magnetic field to control the movement of said magnetic element.