Systems and methods for sensing multiple temperature conditions during tissue ablation

• US 5,688,267 A
• Filed: 05/01/1995
• Issued: 11/18/1997
• Est. Priority Date: 05/01/1995
• Status: Expired due to Term

• Current Assignee: EP Technologies Incorporated (Boston Scientific Corporation)
• Original Assignee: EP Technologies Incorporated (Boston Scientific Corporation)
• Inventors: Panescu, Dorin, Swanson, David K., Fleischman, Sidney D., Bourne, Thomas M.
• Primary Examiner(s): Bahr, Jennifer
• Assistant Examiner(s): PEFFLEY, MICHAEL F
• Application Number:
  US08/432,091
• Time in Patent Office: 932 Days
• Field of Search: 606/27-34, 606/37-42, 606/45-50, 607/100-102, 607/115, 607/116, 607/122
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1206 Generators 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 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/0069 using fuzzy logic
• CPC Class Codes: A61B 2018/00761 Duration
• CPC Class Codes: A61B 2018/00886 Duration
• CPC Class Codes: A61B 2018/126 bipolar
• CPC Class Codes: A61B 2018/1861 with an instrument inserted into a body lumen or cavity, e.g. a catheter
• CPC Class Codes: A61N 1/403 for thermotherapy, e.g. hyperthermia

Abstract

Systems and methods for ablating body tissue use an electrode for contacting tissue to form a tissue-electrode interface. The electrode is adapted to be connected to a source of ablation energy to conduct ablation energy for transmission by the electrode into tissue at the tissue-electrode interface. The electrode is preferably cooled. The systems and methods include multiple temperature sensing elements. One element senses tissue temperature. A second element senses electrode temperature. A third element senses the rate at which the electrode is cooled. The systems and methods control the supply of ablation energy to the electrode based, at least in part, upon the multiple temperatures sensed by the different temperature sensing elements.

Claims

1. A system for ablating body tissue comprising

an electrode for contacting tissue to form a tissue-electrode interface, the electrode adapted to be connected to a source of ablation energy to conduct ablation energy for transmission by the electrode into tissue at the tissue-electrode interface,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue, the carrier being substantially isolated from thermal conductive contact with the electrode, and

a second temperature sensing element in thermal conductive contact with the electrode.

5. A system according to claim 1 or 2 or 3 or 4 and further including a mechanism on the electrode attached to the carrier to selectively advance the carrier relative to the electrode between a first position in which the tissue temperature sensing element is withdrawn from thermal conductive contact with tissue beneath the tissue-electrode interface and a second position in which the tissue temperature sensing element is placed into thermal conductive contact with tissue beneath the tissue-electrode interface.

6. A system according to claim 1 or 2 or 3 or 4 wherein the carrier has a thermal conductivity of at least 1.0 W/m K.

7. A system according to claim 1 or 2 or 3 or 4 wherein the carrier includes a metallic material.

8. A system according to claim 7 wherein the metallic material is substantially isolated from thermal conductive contact with the electrode.

9. A system according to claim 7 wherein the metallic material is selected from the group consisting essentially of stainless steel, gold, silver alloy, platinum, copper, nickel, titanium, aluminum, and compositions containing stainless steel, gold, silver, platinum, copper, nickel, titanium, and aluminum.

2. A system for ablating body tissue comprising

an electrode for contacting tissue to form a tissue-electrode interface, the electrode adapted to be connected to a source of ablation energy to conduct ablation energy for transmission by the electrode into tissue at the tissue-electrode interface,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface, the carrier being substantially isolated from thermal conductive contact with the electrode, and

a second temperature sensing element in thermal conductive contact with the electrode.

3. A system for ablating body tissue comprising

a source of ablation energy,

an electrode for contacting tissue to form a tissue-electrode interface, the electrode being connected to the source of ablation energy to transmit ablation energy at a determinable power level into tissue at the tissue-electrode interface,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue, the carrier being substantially isolated from thermal conductive contact with the electrode,

a second temperature sensing element in thermal conductive contact with the electrode, and

a controller coupled to the source of ablation energy, the tissue temperature sensing element, and the second temperature sensing element to regulate the power level in response to temperatures sensed by both the tissue temperature sensing element and the second temperature sensing element.

4. A system for ablating body tissue comprising

a source of ablation energy,

an electrode for contacting tissue to form a tissue-electrode interface, the electrode being connected to the source of ablation energy to transmit ablation energy at a determinable power level into tissue at the tissue-electrode interface,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface, the carrier being substantially isolated from thermal conductive contact with the electrode,

a second temperature sensing element in thermal conductive contact with the electrode, and

a controller coupled to the source of ablation energy, the tissue temperature sensing element, and the second temperature sensing element to regulate the power level in response to temperatures sensed by both the tissue temperature sensing element and the second temperature sensing element.

10. A system for ablating body tissue comprising

an electrode for contacting tissue to form a tissue-electrode interface, the electrode adapted to be connected to a source of ablation energy to conduct ablation energy for transmission by the electrode into tissue at the tissue-electrode interface,

an element coupled to the electrode to cool the electrode,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface, the carrier being substantially isolated from thermal conductive contact with the electrode, and

a second temperature sensing element in thermal conductive contact with the electrode.

16. A system according to claim 10 or 11 or 12 or 13 or 14 or 15 and further including a mechanism an the electrode attached to the carrier to selectively advance the carrier relative to the electrode between a first position in which the tissue temperature sensing element is withdrawn from thermal conductive contact with tissue beneath the tissue-electrode interface and a second position in which the tissue temperature sensing element is placed into thermal conductive contact with tissue beneath the tissue-electrode interface.

17. A system according to claim 10 or 11 or 12 or 13 or 14 or 15 wherein the carrier has a thermal conductivity of at least 1.0 W/m K.

18. A system according to claim 10 or 11 or 12 or 13 or 14 or 15 wherein the carrier includes a metallic material.

19. A system according to claim 18 wherein the metallic material is substantially isolated from thermal conductive contact with the electrode.

20. A system according to claim 18 wherein the metallic material is selected from the group consisting essentially of stainless steel, gold, silver alloy, platinum, copper, nickel, titanium, aluminum, and compositions containing stainless steel, gold, silver, platinum, copper, nickel, titanium, and aluminum.

11. A system for ablating body tissue comprising

an electrode for contacting tissue to form a tissue-electrode interface, the electrode adapted to be connected to a source of ablation energy to conduct ablation energy for transmission by the electrode into tissue at the tissue-electrode interface,

an element including a source of cooling media and a conduit coupling the source to the electrode to direct cooling media into thermal conductive contact with the electrode,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface, the carrier being substantially isolated from thermal conductive contact with the electrode, and

a second temperature sensing element for sensing temperature variations in the cooling media as a result of thermal conductive contact with the electrode.

12. A system for ablating body tissue comprising

an electrode for contacting tissue to form a tissue-electrode interface, the electrode adapted to be connected to a source of ablation energy to conduct ablation energy for transmission by the electrode into tissue at the tissue-electrode interface,

an element including a source of cooling media and a conduit coupling the source to the element to direct cooling media into thermal conductive contact with the electrode,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface, the carrier being substantially isolated from thermal conductive contact with the electrode,

a second temperature sensing element in thermal conductive contact with the electrode, and

a third temperature sensing element for sensing temperature variations in the cooling media as a result of thermal conductive contact with the electrode.

13. A system for ablating body tissue comprising

a source of ablation energy,

an electrode for contacting tissue to form a tissue-electrode interface, the electrode being connected to the source of ablation energy to transmit ablation energy at a determinable power level into tissue at the tissue-electrode interface,

an element coupled to the electrode to cool the electrode,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface, the carrier being substantially isolated from thermal conductive contact with the electrode,

a second temperature sensing element in thermal conductive contact with the electrode, and

a controller coupled to the source of ablation energy, the tissue temperature sensing element, and the second temperature sensing element to regulate the power level in response to temperatures sensed by both the tissue temperature sensing element and the second temperature sensing element.

14. A system for ablating body tissue comprising

a source of ablation energy,

an electrode for contacting tissue to form a tissue-electrode interface, the electrode being connected to the source of ablation energy to transmit ablation energy at a determinable power level into tissue at the tissue-electrode interface,

an element including a source of cooling media and a conduit coupling the source to the electrode to direct cooling media into thermal conductive contact with the electrode,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface, the carrier being substantially isolated from thermal conductive contact with the electrode,

a second temperature sensing element for sensing temperature variations in the cooling media as a result of thermal conductive contact with the electrode, and

a controller coupled to the source of ablation energy, the tissue temperature sensing element, and the second temperature sensing element to regulate the power level in response to temperatures sensed by both the tissue temperature sensing element and the second temperature sensing element.

15. A system for ablating body tissue comprising

a source of ablation energy,

an electrode for contacting tissue to form a tissue-electrode interface, the electrode being connected to the source of ablation energy to transmit ablation energy at a determinable power level into tissue at the tissue-electrode interface,

an element including a source of cooling media and a conduit coupling the source to the element to direct cooling media into thermal conductive contact with the electrode,

a tissue temperature sensing element,

a carrier on the electrode holding the tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface, the carrier being substantially isolated from thermal conductive contact with the electrode,

a second temperature sensing element in thermal conductive contact with the electrode,

a third temperature sensing element for sensing temperature variations in the cooling media as a result of thermal conductive contact with the electrode, and

a controller coupled to the source of ablation energy, the tissue temperature sensing element, the second temperature sensing element, and the third temperature sensing element to regulate the power level in response to temperatures sensed by the tissue temperature sensing element, the second temperature sensing element, and the third temperature sensing element.

21. A method for ablating heart tissue comprising the steps of

deploying an electrode into a heart chamber for contacting heart tissue to form a tissue-electrode interface,

conducting ablation energy to the electrode for transmission by the electrode into tissue at the tissue-electrode interface,

locating a tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface,

locating an electrode temperature sensing element in thermal conductive contact with the electrode, and

controlling the step of conduction of ablation energy to the electrode based, at least in part, upon temperatures sensed by the tissue temperature sensing element and the electrode temperature sensing element.

22. A method according to claim 21 and further including the step of selectively moving the tissue temperature sensing element between a first position, in which the tissue temperature sensing element is withdrawn from thermal conductive contact with tissue, and a second position, in which the tissue temperature sensing element is placed into thermal conductive contact with tissue.

23. A method according to claim 22 and further including the step of cooling the electrode.

28. A method according to claim 21 or 24 or 26 wherein the step of conducting ablation energy conducts radio frequency energy.

24. A method for ablating heart tissue comprising the steps of

deploying an electrode into a heart chamber for contacting heart tissue to form a tissue-electrode interface,

conducting ablation energy to the electrode for transmission by the electrode into tissue at the tissue-electrode interface,

cooling the electrode at least in part while the electrode transmits ablation energy,

locating a tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface,

locating an electrode temperature sensing element in thermal conductive contact with the electrode, and

controlling either the step of conduction of ablation energy to the electrode or the step of cooling of the electrode or both steps based, at least in part, upon temperatures sensed by the tissue temperature sensing element and the electrode temperature sensing element.

25. A method according to claim 24 and further including the step of selectively moving the tissue temperature sensing element between a first position, in which the tissue temperature sensing element is withdrawn from thermal conductive contact with tissue, and a second position, in which the tissue temperature sensing element is placed into thermal conductive contact with tissue.

26. A method for ablating heart tissue comprising the steps of

deploying an electrode into a heart chamber for contacting heart tissue to form a tissue-electrode interface,

conducting ablation energy to the electrode for transmission by the electrode into tissue at the tissue-electrode interface,

cooling the electrode at least in part while the electrode transmits ablation energy by directing cooling media into thermal conductive contact with the electrode,

locating a tissue temperature sensing element in thermal conductive contact with tissue beneath the tissue-electrode interface,

locating an electrode temperature sensing element in thermal conductive contact with the electrode,

locating a third temperature sensing element to sense temperature variations in the cooling media as a result of thermal conductive contact with the electrode,

controlling either the step of conduction of ablation energy to the electrode or the step of cooling of the electrode or both steps based, at least in part, upon temperatures sensed by at least two of the tissue temperature sensing element, the electrode temperature sensing element, and the third temperature sensing element.

27. A method according to claim 26 and further including the step of selectively moving the tissue temperature sensing element between a first position, in which the tissue temperature sensing element is withdrawn from thermal conductive contact with tissue, and a second position, in which the tissue temperature sensing element is placed into thermal conductive contact with tissue.