Low power tissue ablation system

• US 8,617,156 B2
• Filed: 12/19/2008
• Issued: 12/31/2013
• Est. Priority Date: 07/11/2005
• Status: Active Grant

• Current Assignee: Medtronic Ablation Frontiers LLC (Medtronic Plc)
• Original Assignee: Medtronic Ablation Frontiers LLC (Medtronic Plc)
• Inventors: Werneth, Randell L., Kunis, Christopher G., Flaherty, J. Christopher, Sherman, Marshall L.
• Primary Examiner(s): Dvorak, Linda
• Assistant Examiner(s): SCOTT, AMANDA L
• Application Number:
  US12/340,414
• Publication Number:
  US 20090182325A1
• Time in Patent Office: 1,838 Days
• Field of Search: 606 32- 45
• US Class Current: 606/41
• 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 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00666 using a threshold value
• CPC Class Codes: A61B 2018/00898 Alarms or notifications created in response to an abnormal condition
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1475 Electrodes retractable in or deployable from a housing

Abstract

Devices, systems and methods are disclosed for the ablation of tissue. Embodiments include an ablation catheter that has an array of ablation elements attached to a deployable carrier assembly. The carrier assembly can be constrained within the lumen of a catheter, and deployed to take on an expanded condition. The carrier assembly includes multiple electrodes that are configured to ablate tissue at low power. Additional embodiments include a system that includes an interface unit for delivering one or more forms of energy to the ablation catheter.

Claims

1. An ablation catheter, comprising:

an elongate tube defining a lumen and having a distal end adapted for insertion into a patient;

at least one resilient arm having a constrained configuration inside the lumen and an expanded configuration outside the lumen;

at least one electrode disposed on the at least one resilient arm, the electrode comprising a tissue contact portion adapted to deliver energy to tissue and a circulating blood contact portion; and

at least two projecting members extending from the circulating blood contact portion to provide rapid and efficient cooling of the electrode.

2. The catheter of claim 1 wherein the at least one electrode has a substantially triangular cross section.

3. The catheter of claim 2 wherein the substantially triangular cross section is an isosceles triangle.

4. The catheter of claim 2 wherein a vertex of the substantially triangular cross section is approximately 75 degrees.

5. The catheter of claim 2 further comprising a plurality of resilient arms and at least one electrode disposed on each arm, wherein the electrodes have a circular positioning in the constrained configuration.

6. The catheter of claim 2 wherein the electrode defines three surfaces, and the at least two projecting members extend from different surfaces.

7. The catheter of claim 1 wherein the projecting members further comprise fins.

8. The catheter of claim 1 wherein the projecting members comprise at least 60% of a total surface area of the at least one electrode.

9. The catheter of claim 1 wherein the projecting members comprise at least 70% of a total surface area of the at least one electrode.

10. The catheter of claim 1 wherein the at least one electrode has a surface area of less than approximately 2.5 mm².

11. The catheter of claim 1 wherein the at least one electrode has a volume of less than approximately 3.0 mm³.

12. The catheter of claim 1 wherein the at least one electrode has a weight of less than approximately 0.05 grams.

13. The catheter of claim 1 wherein the projecting members enable rapid cooling of the at least one electrode from an ablation temperature to a body temperature in less than 20 seconds after an ablation cycle has ceased.

14. The catheter of claim 13 wherein the ablation temperature is approximately 60°

C. and the body temperature is approximately 37°

C.

15. The catheter of claim 1 wherein the projecting members enable rapid cooling of the at least one electrode from an ablation temperature to a body temperature in less than 10 seconds after an ablation cycle has ceased.

16. The catheter of claim 15 wherein the ablation temperature is approximately 60°

C. and the body temperature is approximately 37°

C.

17. The catheter of claim 1 wherein the at least one electrode is adapted to increase in temperature from a body temperature to an ablation temperature in less than 5 seconds.

18. The catheter of claim 17 wherein the ablation temperature is approximately 60°

C. and the body temperature is approximately 37°

C.

19. The catheter of claim 1 wherein the projecting members have an opening which enhances cooling of the at least one electrode by allowing circulating blood to pass within an interior of the at least one electrode.

20. An ablation catheter, comprising:

an elongate-tube defining a lumen and having a distal end adapted for insertion into a patient;

at least one resilient arm having a constrained configuration inside the lumen and an expanded configuration outside the lumen; and

at least one electrode disposed on the at least one resilient arm, the at least one electrode having;

an electrical tissue contact portion adapted to deliver energy to tissue,

a thermal dissipation portion electrically isolated and positioned away from the electrical portion and adapted to dissipate heat from the electrical portion into circulating blood, and

a fin projecting from the thermal dissipation portion.

21. The catheter of claim 20, further comprising a second fin projecting from the thermal portion.

22. The catheter of claim 20 wherein the at least one electrode has a substantially triangular cross section.

23. The catheter of claim 20 wherein the at least one electrode has a substantially semicircular cross section.

24. The catheter of claim 20 wherein a cross section of the at least one electrode has a curvilinear segment.

25. The catheter of claim 20 wherein a cross section of the at least one electrode has a serpentine segment.

26. The catheter of claim 20 wherein a cross section of the at least one electrode has a zigzag segment.

27. The catheter of claim 20 wherein the thermal portion comprises at least 60% of a total surface area of the at least one electrode.

28. The catheter of claim 20 wherein the thermal portion comprises at least 70% of a total surface area of the at least one electrode.