Heart ablation catheter with expandable electrode and method of coupling energy to an electrode on a catheter shaft

• US 5,860,974 A
• Filed: 02/11/1997
• Issued: 01/19/1999
• Est. Priority Date: 07/01/1993
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Corporation
• Inventors: Abele, John E.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US08/797,720
• Time in Patent Office: 707 Days
• Field of Search: 606/41, 607/98, 607/99, 607/122, 607/126, 600/374, 600/381, 600/439, 600/467, 600/470
• US Class Current: 606/41
• CPC Class Codes: A61B 17/2202 the ultrasound transducer being inside patient's body at the distal end of the catheter
• 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 2017/00924 for ultrasonic waves
• CPC Class Codes: A61B 2017/22051 with an inflatable part, e.g. balloon, for positioning, blocking, or immobilisation A61B2017/22048, A61B2017/3486 take precedence
• CPC Class Codes: A61B 2017/22077 with a part piercing the tissue A61B2017/22044 takes precedence
• CPC Class Codes: A61B 2017/22082 after introduction of a substance
• CPC Class Codes: A61B 2017/22084 stone- or thrombus-dissolving
• CPC Class Codes: A61B 2018/00077 high, i.e. electrically conducting
• CPC Class Codes: A61B 2018/00148 with metal
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00273 Anchoring means for temporary attachment of a device to tissue
• CPC Class Codes: A61B 2018/00285 Balloons
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/1425 Needle
• CPC Class Codes: A61B 2018/1435 Spiral
• CPC Class Codes: A61B 2034/2063 Acoustic tracking systems, e.g. using ultrasound
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 8/12 : in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/445 : Details of catheter construction
• CPC Class Codes: A61B 8/4461 : Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe

Abstract

An expandable ablation electrode is provided on a catheter constructed to access the heart. When the electrode is introduced to the heart, it is small and suitably flexible to maneuver through the torturous path. However, when the catheter is in place in the heart, the electrode is expansible in diameter to a substantially larger dimension, and is relatively rigid, enabling a large conductive surface to press against the heart tissue with the desired contact pressure. When RF energy is then applied to the electrode it produces a burn lesion of desired large size and depth. This overcomes the limitations to size that have been encountered using conventional rigid electrodes.

Claims

1. A catheter device, comprising:

an elongated, flexible catheter shaft comprising an expandable portion;

an ablation electrode located on said expandable portion of the catheter shaft and constructed to access a heart; and

an electrical conductor located on said catheter shaft and positioned to capacitively couple radio-frequency energy to said electrode to cause said electrode to produce a burn lesion;

said catheter shaft portion being expansible in diameter from a small profile to a large profile;

said catheter shaft portion being sufficiently small and flexible in said small profile to maneuver into said heart through a tortuous path, and being more rigid in said large profile to permit a conductive surface of said electrode to be pressed against heart tissue with suitable contact pressure.

2. A catheter device in accordance with claim 1, wherein said electrode is substantially thermally conductive.

3. A catheter device in accordance with claim 1, wherein the electrode is a monopole electrode.

4. A catheter device in accordance with claim 1, wherein said expandable shaft portion comprises a balloon.

5. A catheter device in accordance with claim 4, wherein an exterior portion of said balloon is coated with a coating of an electrically and thermally conductive material.

6. A catheter device in accordance with claim 5, wherein said coating is of a pattern chosen to enable said balloon to stretch.

7. A catheter device in accordance with claim 6, wherein said pattern is a series of metal conductive dots applied to an exterior surface of said balloon.

8. A catheter device in accordance with claim 7, wherein said balloon is constructed to enable capacitive coupling between said dots and an electrically conductive fluid employed as an inflation medium for said balloon.

9. A catheter device in accordance with claim 8, further comprising an electrode mounted on said catheter shaft and extending into said balloon, said electrode being configured to provide electrical current to fluid within said balloon when said balloon is inflated.

10. A catheter device in accordance with claim 4, wherein said balloon is constructed of a compliant material and is constructed to permit a user to select an outer dimension of said balloon when inflated by selecting a volume of inflation fluid that is introduced into said balloon to inflate said balloon.

11. A catheter device in accordance with claim 10, wherein said compliant material is an elastomer.

12. A catheter device in accordance with claim 4, further comprising a high-accuracy screw syringe attached to said catheter shaft and constructed to precisely control the amount of fluid introduced to said balloon.

13. A catheter device in accordance with claim 4, further comprising an additional electrode disposed on said catheter shaft.

14. A catheter device in accordance with claim 13, wherein said additional electrode is an electrophysiological mapping electrode.

15. A catheter device in accordance with claim 1, further comprising an ultrasound imaging device incorporated into said catheter shaft.

16. A catheter device in accordance with claim 1, further comprising a fluid dispensing lumen in said catheter shaft.

17. A catheter device, comprising:

an elongated, flexible catheter shaft;

an first electrode disposed on said catheter shaft; and

a second electrode disposed within the shaft and separated from the first electrode by a dielectric, such second electrode being positioned with respect to the first electrode to capacitively couple radio frequency energy to the second electrode through the dielectric.

18. The catheter device recited in claim 17 wherein the shaft has an expandable portion and wherein the first electrode is disposed on the expandable portion of the shaft.

19. The catheter recited in claim 18 wherein the expandable portion of the shaft comprises a balloon.

20. The catheter recited in claim 17 wherein the shaft has disposed thereon a plurality of first electrodes, each one thereof being capacitively coupled to said second electrode.

21. The catheter device recited in claim 20 wherein the shaft has an expandable portion and wherein the plurality of first electrodes are disposed on the expandable portion of the shaft.

22. A method of coupling energy to an electrode disposed on an elongated, flexible catheter shaft, comprising;

disposing a radio frequency energy coupling electrode within the shaft and separated from the first mentioned electrode by a dielectric, such coupling electrode being positioned with respect to the first mentioned electrode to capacitively couple radio frequency energy to the first mentioned electrode through the dielectric; and

capacitively coupling radio frequency energy from the coupling electrode to the first mentioned electrode through the dielectric.