Even temperature linear lesion ablation catheter

• US 6,780,181 B2
• Filed: 08/29/2001
• Issued: 08/24/2004
• Est. Priority Date: 06/22/1998
• Status: Expired due to Term

• Current Assignee: St. Jude Medical (Abbott Laboratories Incorporated)
• Original Assignee: St. Jude Medical, Daig Division, Inc.
• Inventors: Kroll, Mark W., Ockuly, John D., Pendakanti, Rajesh
• Primary Examiner(s): GIBSON, ROY DEAN
• Application Number:
  US09/941,522
• Publication Number:
  US 20040039382A1
• Time in Patent Office: 1,091 Days
• Field of Search: 606/41-52, 607/96-102
• 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 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00363 Epicardium
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00791 Temperature

Abstract

A linear lesion ablation catheter includes a conductive ablating portion having a predetermined resistivity profile for ablating tissue in a generally even temperature profile. In one embodiment, the conductive ablating portion is disposed on a distal portion of an elongate flexible member and has a resistance that increases exponentially along its length from a center of the ablating portion to a non-infinite value at opposite ends of the ablating portion. The ablating portion is adapted to produce a generally even temperature profile along a length of its surface when the ablating portion is in contact with a target tissue within a patient'"'"'s body. In one example, the conductive ablating portion comprises a plurality of electrically connected conductive regions which extend from the center to the opposite ends of the ablating portion. Each of the conductive regions has a resistance value wherein the resistance values increase from section to section in successive orders of magnitude from the center of the ablating portion to the opposite ends of the ablating portion exponentially up to a non-infinite value. This predetermined resistivity profile produces linear lesions on target tissue without the resulting “edge effects” or “hot spots” at the ends of the electrode common in prior art linear lesion ablation catheters.

Claims

1. An ablation catheter comprising:

an elongate flexible member; and

a conductive ablating element secured to the elongated flexible member, wherein the resistance of the ablating element over its outer surface is predetermined such that during an ablating procedure, the temperature of the ablating element is generally consistent over the length of the outer surface of the ablating element.

2. The ablation catheter of claim 1, wherein a resistivity profile of the ablating element is predetermined.

3. The ablation catheter of claim 1 further comprising:

an electrical conductor extending within the member having proximal and distal ends, wherein the proximal end of the conductor is adapted for connection to an external power source and the distal end of the conductor is connected to the conductive ablating element.

4. The ablation catheter of claim 1, wherein the conductive ablating element comprises a plurality of electronically connected conductive regions which extend from the center of the conductive ablating element to a first and a second end of the conductive ablating element.

5. The ablation catheter in claim 3, wherein the electrical conductor comprises a single electrically conductive wire.

6. The ablation catheter in claim 1, wherein the electrical conductor comprises a plurality of electrically conductive wires.

7. The ablation catheter in claim 1, wherein the ablating element comprises at least three electrically conductive regions, wherein a first region has a resistance with a first value, a second region has a resistance with a second value, and a third region has a resistance with a third value, wherein the first region is disposed closest to the center of the ablating element and the third region is disposed closest to one end of the ablating element.

8. The ablation catheter of claim 7, wherein the resistance value of the first region is at least about 0 ohms per centimeter, the resistance value of the second region is at least about 10 ohms per centimeter, and the resistance value of the third region is at least about 100 ohms per centimeter.

9. The ablation catheter of claim 7, wherein the ablating element has length of at least about four centimeters, the first region has a length of at least about 1.3 centimeters and extends from the center of the ablating element towards one of the ends of the ablating element, the second region has a length of at least about 0.4 centimeters and extends from first region toward one end of the ablating element, and the third region has a length of at least about 0.3 centimeters that extends from the second region to the end of the ablating element.

10. The ablation catheter of claim 7, wherein the resistance value of the first region is at least about 50 ohms per centimeter, the resistance value of the second region is at least about 250 ohms per centimeter, and the resistance value of the third region is at least about 1250 ohms per centimeter.

11. The ablation catheter of claim 7, wherein the ablating element has length of at least about one centimeter and the first region has a length of about 0.35 centimeters that extends from the center of the ablating surface towards one of the ends of the element, the second region has a length of at least about 0.10 centimeters that extends from first region toward one end of the ablating element, and the third region has a length of at least about 0.05 centimeters that extends from the second region to the end of the ablating surface.

12. The ablation catheter of claim 7, wherein the first region has a length of about 65 to 70 percent of the length of the ablating element that extends from the center of the ablating element towards one of the ends of the element, the second region has a length of about 20 percent of the length of the ablating element that extends from the center toward the end of the element, and the third region has a length of about 10 to 15 percent of the length of the ablating element that extends from the center to a second end of the surface.

13. A process for ablating tissue within a body comprising

positioning an electrode of an ablation catheter in the body adjacent to the tissue to be ablated, wherein the ablation catheter comprises the ablation catheter of claim 1, and

ablating the target tissue with an ablating element of the ablation catheter.

14. The process of claim 13, further comprising applying an electrical ablating signal to the conductive ablating element at a resistance that increases in value along a length of the ablating element from a midpoint to a non-infinite at the ends of the ablating element.

15. The process of claim 13, further comprising

arranging at least three electrically conductive regions of resistance in series on the ablating element, wherein the conductive regions comprise a first region having a resistance with a first value, a second region having a resistance with a second value, and a third region having a resistance with a third value.

16. The process of claim 15 further comprising extending the first region over a length of about 65 to 70 percent of the length of the electrode that extends from a center of the electrode towards one of the ends of the electrode:

extending the second region over a length of at least about 20 percent of the length of the electrode that extends from the midpoint toward the end of the electrode; and

extending the third region over a length of at least about 10 to 15 percent of the length of the electrode that extends from the center to the end of the electrode.

17. The process of claim 16, wherein the extending steps further comprise:

providing the first region with a resistance value of at least;

about 0 ohms percent centimeter;

providing the second region with a resistance value of at leant about 10 ohms per centimeter; and

providing the third region with a resistance value of at least about 100 ohms per centimeter.

18. The process of claim 16, wherein the extending steps further comprise:

providing the first region with a resistance value of at least about 50 ohms per centimeter,

providing the second region with a resistance value of at least about 250 ohms per centimeter, and

providing the third region with a resistance value of at least about 1250 ohms per centimeter.

19. An ablation catheter comprising

an elongate flexible member, and

a conductive ablating element secured to the elongate flexible member, wherein the resistance element comprises a plurality of ablating sections, wherein the resistance of the ablating element varies over the length of the ablating element, and wherein during an ablating procedure the temperature of the ablating section is generally uniform along an outer surface of the ablating section.

20. The ablation catheter of claim 19, wherein the ablating sections comprise a plurality of ring electrodes.

21. An ablation catheter comprising

an elongate flexible member, and

a conductive ablating element secured to the elongate flexible member, wherein the resistance over an outer surface of the ablating element varies, wherein the ablating element comprises a film of conductive material secured to an outside surface of the elongate flexible member and wherein during an ablating procedure the temperature of the ablating element is generally uniform ever element the outer surface of the ablating element.