Ablation Device With Cooled Electrodes And Methods of Use

• US 20100305562A1
• Filed: 04/26/2010
• Published: 12/02/2010
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Atricure, Inc.
• Original Assignee: Atricure, Inc.
• Inventors: Gilthero, Jason Iain, Drachman, David J., Hooven, Michael D., Staats, Peter F., Winkler, Matthew J., Williamson, Warren P. IV
• Granted Patent: US 8,998,892 B2
• Time in Patent Office: Days
• US Class Current: 606/33
• CPC Class Codes: A61B 18/1482 having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/1475 Electrodes retractable in or deployable from a housing

Abstract

An electrosurgical end effector for ablating tissue is provided that comprises at least one electrically-conductive ablation member adapted to be connected to a source of RF energy, with the ablation member having a tissue engaging surface and an internal fluid passageway. Preferably, the end effector includes two electrically conductive ablation members that are electrically isolated from one another.

Claims

1. A device for ablating target tissue comprising:

an end effector having at least two generally elongated, parallel ablation electrodes adapted to be conductively attached to a source of RF energy such that, when activated, the electrodes are of opposite polarity;

a fluid pathway within the end effector;

source of fluid in communication with the fluid pathway, the fluid being circulated through the pathway for cooling the electrodes; and

means for enhancing contact between the ablation electrodes and the target tissue.

2. The device of claim 1 wherein the fluid pathway is closed.

3. The device of claim 1 wherein the end effector further comprises an electrically-insulating material separating the electrodes from the fluid pathway.

4. The device of claim 3 wherein the electrically-insulating material comprises a polymer.

5. The device of claim 1 wherein the means for enhancing contact comprises at least one suction port adjacent the electrodes.

6. The device of claim 1 wherein the means for enhancing contact comprises an expandable member.

7. The device of claim 6 wherein the expandable member is in fluid communication with the source of fluid so as to be inflatable thereby.

8. The device of claim 1 further comprising at least one sensor electrode located on the end effector between the ablation electrodes.

9. The device of claim 1 further comprising an elongated shaft having a distal end to which the end effector is mounted.

10. The device of claim 9 wherein the elongated shaft comprises a flexible material.

11. The device of claim 9 wherein the elongated shaft comprises a rigid, malleable material.

12. The device of claim 1 further comprising a bi-polar RF generator conductively connected to the electrodes.

13. A method for epicardial ablation of heart tissue, the heart tissue having overlying pericardial tissue, the method comprising:

accessing the epicardial surface in a minimally invasive procedure;

providing an ablation catheter having at least a first pair of electrodes on the distal end thereof, the electrodes being connected to an RF energy source so that, when activated, the electrodes are of opposite polarity;

positioning the electrodes to be in contact with the epicardial surface at a desired location;

spacing the electrodes from the overlying pericardial tissue by enlargement of at least one expansion member associated with the ablation catheter adjacent the electrodes; and

activating the electrodes with RF energy to create a line of ablation on the epicardial surface.

14. The method of claim 13 wherein the expansion member is a balloon and the method including circulating a liquid through the balloon.

15. The method of claim 13 wherein the ablation catheter is provided with a plurality of electrode pairs with the electrodes in each pair being of opposite polarity.

16. The method of claim 13 wherein the ablation catheter is adapted to be advanced through a guide catheter, the distal end of the ablation catheter on which the electrodes are disposed having a lateral dimension greater than a diameter of the guide catheter, the distal end of the ablation catheter being compactable to facilitate introduction into and advancement through the guide catheter, the distal end of the ablation catheter being expandable upon advancement from the open distal end of the guide catheter.

17. A method for ablating a left atrium of a heart adjacent esophageal tissue, the left atrium having an epicardial surface with overlying pericardial tissue, the method comprising:

accessing the left atrium between the epicardial surface of the left atrium and the overlying pericardial tissue with a guide catheter having an open distal end introduced in a minimally invasive procedure;

providing an ablation catheter having at least a first pair of electrodes on the distal end thereof, the electrodes being connected to an RF energy source so that, when activated, the electrodes are of opposite polarity;

advancing the ablation catheter through the guide catheter and out the distal end of the guide catheter so that the electrodes are in contact with the epicardial surface of the left atrium at a desired location;

spacing the electrodes from the overlying pericardial and esophageal tissue by inflation of at least one balloon member associated with the ablation catheter adjacent the electrodes; and

activating the electrodes with RF energy to create a line of ablation on the epicardial surface of the left atrium.

18. The method of claim 17 wherein the balloon is inflated with a liquid that is circulated through the balloon.

19. The method of claim 17 wherein the ablation catheter is provided with a plurality of electrode pairs with the electrodes in each pair being of opposite polarity.

20. The method of claim 17 wherein the distal end of the ablation catheter on which the electrodes are disposed has a lateral dimension greater than a diameter of the guide catheter, such that the distal end of the ablation catheter is compacted to facilitate introduction into and advancement through the guide catheter, the distal end of the ablation catheter expanding upon advancement out of the open distal end of the guide catheter.

21. An ablation catheter having a proximal end and a distal end and adapted to be advanced through a guide catheter, comprising:

an elongated tubular member extending between the proximal and distal ends, the distal end being enlarged relative to the tubular member and supporting at least a first pair of electrodes and an expandable member, a conductive member carried by the tubular member associated with each electrode for the delivery of ablation energy thereto, the tubular member comprising at least a first lumen for delivery of pressurized fluid to the expandable member, wherein the enlarged distal end is capable of compaction to a size so as to permit advancement through the guide catheter and having shape memory so as to substantially return to its original size and shape upon exiting the guide catheter.

22. The ablation catheter of claim 21 wherein the distal end is provided with a plurality of electrode pairs.

23. The ablation catheter of claim 22 wherein the electrodes in each pair are spaced apart on opposite sides of a longitudinal center line.

24. The ablation catheter of claim 21 wherein each electrode has a tissue contact surface area with an aspect ratio (length:

width) of from 3 to about 1.

25. The ablation catheter of claim 21 wherein the tubular member further comprises a second lumen in fluid communication with the first lumen at the distal end of the ablation catheter so as to permit circulation of pressurized fluid through the expandable member.

26. The ablation catheter of claim 21 wherein the distal end is remotely steerable.

27. The ablation catheter of claim 26 wherein the distal end is bi-directionally steerable.

28. The ablation catheter of claim 21 further comprising a flexible, sheet-like pad having first and second sides, the electrodes being raised from the first side of the pad and the expandable member being secured to the second side of the pad.

29. The ablation catheter of claim 28 wherein the electrodes are secured to the first side of the pad.

30. The ablation catheter of claim 28 wherein the pad includes apertures for receiving the electrodes and the electrodes include flanges for engaging the second side of the pad to maintain the electrodes in position.

31. The ablation catheter of claim 21 further comprising a steerable sheath.