Apparatus and method for linear lesion ablation

• US 6,119,041 A
• Filed: 08/04/1998
• Issued: 09/12/2000
• Est. Priority Date: 03/06/1996
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Cardiac Pathways Corp. (Boston Scientific Corporation)
• Inventors: Sherman, Darren R., Chapman, Troy J., Imran, Mir, Pomeranz, Mark L.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US09/128,877
• Time in Patent Office: 770 Days
• Field of Search: 607/98, 607/99, 607/101, 607/112, 607/113, 607/122, 607/116, 607/148, 607/149, 607/153, 600/373, 600/372, 606/41, 606/22
• US Class Current: 607/101
• CPC Class Codes: A61B 17/00234 for minimally invasive surgery A61B17/0218, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• 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 2017/00243 cardiac
• CPC Class Codes: A61B 2018/00005 Cooling or heating of the probe or tissue immediately surrounding the probe
• CPC Class Codes: A61B 2018/00011 with fluids
• CPC Class Codes: A61B 2018/00065 porous
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00113 with foam
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00654 with individual control of each of a plurality of energy emitting elements
• CPC Class Codes: A61B 2018/00821 measured by a thermocouple
• CPC Class Codes: A61B 2018/1407 Loop
• CPC Class Codes: A61B 2018/1437 whereby the windings of the spiral touch each other such as to create a continuous surface
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2018/1475 Electrodes retractable in or deployable from a housing
• CPC Class Codes: A61B 2218/002 Irrigation
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/06 : for high-frequency therapy

Abstract

An apparatus for ablating body tissue, and particularly for creating linear lesions within a chamber of a patient'"'"'s heart, includes an elongate member having an ablation section. The ablation section includes an infusion tube and a plurality of spaced electrodes. The infusion tube and electrodes are covered by a fluid permeable foam material, and the foam material is covered by a fluid impermeable covering having a plurality of holes formed in it. During use, the ablation section is positioned against tissue to be ablated. Radiofrequency energy is delivered to he electrodes while saline or other conductive fluid is delivered to the infusion tube. The fluid exits the infusion tube at the ablation section, contacts the electrodes, and carries RF energy from the electrodes through the foam, through the holes in the covering and into contact with the body tissue to form a burn in the body tissue.

Claims

1. An apparatus for creating linear lesions in body tissue, the apparatus comprising:

an elongate support member proportioned for insertion and manipulation through human vessels, the support member having an elongate ablation section;

at least one electrode carried by the ablation section of the support member;

a fluid permeable deformable member at least partially covering the electrodes, the deformable member having a surface that is deformable independently of the elongate support member in response to contact between the surface and body tissue;

means for delivering current to the electrodes; and

means for delivering conductive fluid through the deformable member to the ablation section to cause said fluid to create a conductive path between the electrodes and the tissue when the electrodes are positioned adjacent body tissue.

2. The apparatus of claim 1 wherein the deformable member includes a layer of foam material formed over the electrodes.

3. The apparatus of claim 1 wherein the deformable member is segmented.

4. A method for ablating body tissue, comprising the steps of:

(a) providing an elongate member, electrodes carried by the member, a deformable layer of fluid permeable material formed over the electrodes, and means for delivering conductive fluid to the electrodes;

(b) manipulating the member through a vessel and into the chamber of a heart, and positioning the layer adjacent to a wall within the heart which is to be ablated;

(c) supplying current to the electrodes;

(d) supplying conductive fluid to the electrodes;

(e) allowing the layer to deform independently of the elongate member in response to contact between its surface and the wall within the heart; and

(f) permitting the conductive fluid to form a conductive path between the electrodes and the tissue which is to be ablated.

5. An assembly carried on the distal end of a catheter for generating a linear lesion in a target tissue comprising:

a central, elongated support member;

a plurality of longitudinally spaced apart electrodes, said electrodes being connectable to a source of RF energy;

an elongated, deformable member surrounding said electrodes and a portion of said support member, the deformable member having a surface that is deformable independently of the elongate support member in response to contact between the surface and body tissue; and

a source of electrolytic fluid coupled to said deformable member, said fluid functioning to partially pressurize said deformable member and wherein said fluid perfuses out of said deformable member towards the target tissue, said fluid enhancing the coupling of the RF energy from said electrodes to said tissue whereby linear lesions can be effectively created in said tissue.

6. An assembly as recited in claim 5 wherein said deformable member is formed in longitudinal segments corresponding to, and aligned with, the electrodes on said support member.

7. An assembly as recited in claim 5 wherein said deformable member includes an inflatable balloon, an outer membrane enclosing the balloon and having apertures formed therein, and means for delivering an inflation medium to the inflatable balloon.

8. An assembly as recited in claim 5 further including a means for biasing said deformable member into contact with the target tissue.

9. An assembly as recited in claim 5 wherein said support member is a wire.

10. An apparatus for creating linear lesions in body tissue, the apparatus comprising:

an elongate support member having an elongate ablation section;

a plurality of spaced electrodes carried by the ablation section of the support member;

a fluid permeable deformable member at least partially covering the electrodes;

a source of RF energy electrically coupled to the electrodes;

a source of conductive fluid fluidly coupled to the ablation section to cause said fluid to create a conductive path between the electrodes and the tissue when the electrodes are positioned adjacent body tissue; and

a covering on the deformable member, the covering formed of a material substantially impermeable to fluid, the covering including at least one opening sized to allow passage of fluid of fluid out of the covering.