Ablation catheter assembly having a virtual electrode comprising portholes

• US 20040143253A1
• Filed: 01/17/2003
• Published: 07/22/2004
• Est. Priority Date: 01/17/2003
• Status: Active Grant

• Current Assignee: St. Jude Medical (Abbott Laboratories Incorporated)
• Original Assignee: St. Jude Medical (Abbott Laboratories Incorporated)
• Inventors: Dando, Jeremy D., Vanney, Guy P., Dudney, Joshua L.
• Granted Patent: US 6,984,232 B2
• Time in Patent Office: Days
• 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 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 2018/00041 Heating, e.g. defrosting
• CPC Class Codes: A61B 2018/00375 Ostium, e.g. ostium of pulmonary vein or artery
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: C08L 2201/12 Shape memory

Abstract

An ablation catheter having a catheter shaft and a virtual electrode, the virtual electrode comprising portholes through an outer peripheral wall of the catheter shaft and a metal electrode, the catheter being used for treatment of cardiac arrhythmia, for example, atrial fibrillation, by electrically isolating a vessel, such as a pulmonary vein, from a chamber, such as the left atrium. The catheter shaft includes a proximal portion and a distal portion. The distal portion includes an active region, which is either a looped structure transverse to the longitudinal axis of the catheter shaft, or a linear structure that extends parallel to the longitudinal axis of the catheter shaft. During use, the active region is directed into contact with, for example, the wall of a pulmonary vein. Upon energization, the virtual electrode creates a continuous lesion on an inner wall of the pulmonary vein, thereby electrically isolating the pulmonary vein from the left atrium.

Claims

1. An ablation catheter for ablating tissue, the ablation catheter comprising

a catheter shaft, said catheter shaft comprising

a proximal portion;

a distal portion, said distal portion being adapted to be inserted into a body cavity having tissue to be ablated and being disposed remotely from said proximal portion, said distal portion comprising an active region including a plurality of portholes; and

a first lumen extend from said proximal portion to said distal portion, said first lumen being adapted to carry a conductive fluid medium from said proximal portion to said portholes along said active region of said distal portion; and

1

a metal electrode mounted within said first lumen and extending along said active region of said distal portion, wherein said metal electrode is adapted to supply ablation energy to the conductive fluid medium.

2. The ablation catheter of claim 1, wherein said conductive fluid medium is hypertonic saline.

3. The ablation catheter of claim 1, wherein said distal portion is straight.

4. The ablation catheter of claim 3, wherein said straight distal portion comprises a first porthole, at least one intermediate porthole, and a last porthole, and wherein said portholes are circular in cross section, and the relative diameter of said portholes increases in size as one moves from said first porthole to said last porthole.

5. The ablation catheter of claim 4, wherein each of said portholes defines a proximal leading edge and a distal trailing edge, and wherein a bridge is defined between a proximal leading edge of one porthole and a distal trailing edge of a next adjacent porthole, and wherein said bridges between adjacent portholes decrease in size as one moves from said first porthole to said last porthole.

6. The ablation catheter of claim 4, wherein said portholes are centered along a porthole centerline defined by a tangent line on a surface of said catheter shaft extending parallel to a longitudinal axis of said catheter shaft on an outer peripheral wall of said distal portion of said ablation catheter.

7. The ablation catheter of claim 1, wherein said distal portion of said catheter shaft includes a first curved section, a second curved section, and a third curved section.

8. The ablation catheter of claim 1, wherein said distal portion of said catheter shaft includes at least one curved section.

9. The ablation catheter of claim 8, wherein said at least one curved section of said catheter shaft includes said plurality of portholes through which the conductive fluid medium is adapted to flow.

10. The ablation catheter of claim 9, wherein said plurality of portholes includes a first porthole, a plurality of intermediate portholes, and a last porthole.

11. The ablation catheter of claim 10, wherein said at least one curved section is shaped in a circular configuration.

12. The ablation catheter of claim 11, wherein said curved section defines an outer peripheral wall, and wherein said portholes extend from said first lumen through a radial apex of said outer peripheral wall.

13. The ablation catheter of claim 12, wherein each of said portholes has a circular cross section, and wherein said first porthole has a diameter that is smaller than the diameters of each of the other portholes, and wherein said last porthole has a diameter that is larger than the diameters of each of the other portholes, and further where the diameters of the portholes increase in size from said first porthole to said last porthole.

14. The ablation catheter of claim 13, wherein each of said portholes is sized so that the conductive fluid medium is adapted to flow evenly from each of said portholes.

15. The ablation catheter of claim 13, wherein each of said portholes defines a proximal leading edge and a distal trailing edge, and wherein a bridge is defined between a proximal leading edge of one porthole and a distal trailing edge of a next adjacent porthole.

16. The ablation catheter of claim 15, wherein each of said bridges has a width, and wherein said width of said bridges narrows from said first porthole to said last porthole.

17. The ablation catheter of claim 15, wherein each of said portholes has a longitudinal centerline, and wherein a distance between said longitudinal centerlines of adjacent portholes remains constant along said active region.

18. The ablation catheter of claim 13, wherein each porthole is separated from at least one next adjacent porthole by a bridge extending between edges of said adjacent portholes.

19. The ablation catheter of claim 13, wherein said portholes are centered on a porthole centerline defined by a longitudinally-extending tangent line on a surface of said catheter shaft on said radial apex of said outer peripheral wall of said at least one curved section.

20. The ablation catheter of claim 1, wherein said metal electrode is a platinum flat wire adapted to be connected to an RF generator by an electrical lead that extends from said distal portion to said proximal portion of said catheter shaft.

21. The ablation catheter of claim 1, wherein said ablation catheter further comprises a shape memory wire.

22. The ablation catheter of claim 21, wherein said catheter shaft further comprises a second lumen extending along said distal portion adjacent to an inner peripheral wall of said distal portion, and wherein said shape memory wire is located within said second lumen.

23. The ablation catheter of claim 22, wherein said shape memory wire comprises an alloy of nickel and titanium.

24. The ablation catheter of claim 22, wherein said shape memory wire comprises a strip of stainless steel.

25. The ablation catheter of claim 1, wherein said distal portion further comprises a tip electrode.

26. The ablation catheter of claim 1, wherein said catheter shaft is bi-lumenal, including a first lumen and a second lumen.

27. The ablation catheter of claim 26, wherein said first lumen has a modified keyhole shape, comprising a nearly-circular subportion mated with a rounded-rectangular subportion.

28. The ablation catheter of claim 27, wherein said nearly-circular subportion mates with said rounded-rectangular subportion at a necked down area defining a pair of retention ledges.

29. The ablation catheter of claim 28, wherein said retention ledges retain said metal electrode in said rounded-rectangular subportion of said first lumen.

30. The ablation catheter of claim 28, wherein said nearly-circular subportion of said first lumen is adapted to carry the conductive fluid medium flowing past and in contact with said metal electrode.

31. The ablation catheter of claim 28, wherein said second lumen carries said shape memory wire.

32. The ablation catheter of claim 26, wherein said distal portion defines an inner peripheral wall and an outer peripheral wall, and wherein said first lumen is adjacent to said outer peripheral wall and said second lumen is adjacent to said inner peripheral wall.

33. The ablation catheter of claim 32, wherein said first lumen further comprises a modified keyhole shape defined by a nearly-circular subportion mated with a rounded-rectangular subportion.

34. The ablation catheter of claim 33, wherein retention ledges are defined at a necked down area between said nearly-circular subportion and said rounded-rectangular subportion of said first lumen, and wherein said retention ledges retain said metal electrode in said rounded-rectangular subportion of said first lumen.

36. An ablation catheter assembly for treatment of cardiac arrhythmia, the ablation catheter assembly comprising

an ablation catheter according to claim 1 or 35;

and

at least one guiding introducer.

37. The ablation catheter assembly of claim 36, wherein said at least one guiding introducer comprises an inner guiding introducer and an outer guiding introducer.

38. An ablation catheter assembly for treatment of cardiac arrhythmia, the ablation catheter assembly comprising

an ablation catheter according to claim 1 or 35;

and

a precurved sheath.

35. An ablation catheter for ablating tissue, the ablation catheter comprising

a catheter shaft, said catheter shaft comprising

a proximal portion;

a distal portion comprising at least one curved section adapted to be inserted into a body cavity having tissue to be ablated, wherein said at least one curved section defines an inner peripheral wall and an outer peripheral wall, and wherein said outer peripheral wall has an active region that includes a plurality of portholes;

a first lumen extending from said proximal portion to said distal portion, said first lumen being adapted to carry a conductive fluid medium from said proximal portion to said portholes along said active region of said distal portion; and

a second lumen extending adjacent to said inner peripheral wall;

a metal electrode mounted in said first lumen and extending along said active region of said distal portion, wherein said metal electrode is adapted to supply ablation energy to the conductive fluid medium; and

a shape memory wire mounted in said second lumen.

39. A method for making a catheter assembly for treating cardiac arrhythmia, the method comprising the steps of

acquiring a shape memory wire having a desired curvilinear shape;

acquiring a catheter shaft having a first lumen formed therein;

inserting said shape memory wire into said first lumen to form a catheter assembly;

heating said catheter shaft until it relaxes and at least partially conforms to said shape of said shape memory wire; and

cooling said catheter assembly.

40. The method of claim 39, wherein said heating step includes heating said catheter assembly to a temperature that permits said catheter shaft to deform, and wherein said temperature remains lower than a temperature used to fix said shape of said shape memory wire.

41. The method of claim 40, wherein a portion of said catheter shaft over said shape memory wire includes a plurality of portholes.

42. The method of claim 39, wherein said shape memory wire comprises an alloy of nickel and titanium.

43. The method of claim 42, wherein said memory wire comprises NiTi.