Circumferential ablation device assembly

• US 20020115995A1
• Filed: 04/25/2002
• Published: 08/22/2002
• Est. Priority Date: 05/09/1997
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Lesh, Michael D., Langberg, Jonathan J., Peacock, James C. III, Ross, Michael Ronald
• Granted Patent: US 6,872,205 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/00 Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body eye surgery A61F9/007; ear surgery A61F11/00
• 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 18/1815 using microwaves
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2017/22038 with a guide wire
• CPC Class Codes: A61B 2017/22054 with two balloons
• CPC Class Codes: A61B 2017/22067 Blocking; Occlusion A61B2017/22054 takes precedence
• CPC Class Codes: A61B 2018/00011 with fluids
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• 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 2018/00291 using suction
• CPC Class Codes: A61B 2018/00369 Heart valves
• CPC Class Codes: A61B 2018/00375 Ostium, e.g. ostium of pulmonary vein or artery
• CPC Class Codes: A61B 2018/00797 measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/00815 measured by a thermistor
• CPC Class Codes: A61B 2018/00821 measured by a thermocouple
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2018/00898 Alarms or notifications created in response to an abnormal condition
• CPC Class Codes: A61B 2018/00994 : combining two or more different kinds of non-mechanical energy or combining one or more non-mechanical energies with ultrasound
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61N 7/02 : Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

This invention is a circumferential ablation device assembly which is adapted to forming a circumferential conduction block in a pulmonary vein. The assembly includes a circumferential ablation element which is adapted to ablate a circumferential region of tissue along a pulmonary vein wall which circumscribes the pulmonary vein lumen, thereby transecting the electrical conductivity of the pulmonary vein against conduction along its longitudinal axis and into the left atrium. The circumferential ablation element includes an expandable member with a working length that is adjustable from a radially collapsed position to a radially expanded position. An equatorial band circumscribes the outer surface of the working length and is adapted to ablate tissue adjacent thereto when actuated by an ablation actuator. The equatorial band has a length relative to the longitudinal axis of the expandable member that is narrow relative to the working length, and is also substantially shorter than its circumference when the working length is in the radially expanded position. A pattern of insulators may be included over an ablation element which otherwise spans the working length in order to form the equatorial band described. The expandable member is also adapted to conform to the pulmonary vein in the region of its ostium, such as by providing a great deal of radial compliance or by providing a taper along the working length which has a distally reducing outer diameter. A linear ablation element is provided adjacent to the circumferential ablation element in a combination assembly which is adapted for use in a less-invasive “maze”-type procedure in the region of the pulmonary vein ostia in the left ventricle.

Claims

1. A circumferential ablation device assembly for ablating a circumferential lesion in a body space wall which circumscribes at least a portion of a body space, comprising:

an elongate body with a proximal end portion, a distal end portion and a longitudinal axis that extends between the proximal and distal end portions;

an expandable member located in the region of the distal end portion and having a working length along the longitudinal axis which is adjustable between a radially collapsed position and a radially expanded position, the working length having a larger outer diameter when in the radially expanded position than when in the radially collapsed position;

an expansion actuator which is coupled to the expandable member and which is adapted to adjust the expandable member from the radially collapsed position to the radially expanded position; and

a circumferential ablation element that includes an equatorial band which circumscribes at least a portion of an outer surface of the working length of the expandable member when in the radially expanded position, the equatorial band having an equatorial band width along the longitudinal axis which is shorter than the working length, the circumferential ablation element being adapted to ablate a circumferential region of tissue adjacent to the equatorial band and along the body space wall when the circumferential ablation element is coupled to and actuated by an ablation actuator.

2. The circumferential ablation device assembly of claim 1, wherein the circumferential ablation element further comprises a circumferential ablation electrode which is electrically coupled to a conductive lead and which is adapted to emit current into the tissue adjacent to the equatorial band when the conductive lead is also coupled to an ablation actuator which includes an electrical current source.

3. The circumferential ablation device assembly of claim 2, wherein the circumferential ablation electrode is located along the outer surface of the working length and includes first and second electrode end portions with a middle electrode portion extending therebetween along the longitudinal axis, and further comprising:

an electrical insulator disposed on an outer surface of each of the first and second electrode end portions, such that only the middle electrode portion is uninsulated and electrically exposed to adjacent tissue and wherein the middle electrode portion thereby forms the equatorial band.

4. The circumferential ablation device assembly of claim 2, wherein the circumferential ablation electrode further comprises at least one discrete electrode element positioned on the outer surface of the working length and which has a circumferential shape with an electrode width along the longitudinal axis which is shorter than the working length, the circumferential ablation electrode thereby forming the equatorial band.

5. The circumferential ablation device assembly of claim 2, further comprising

a return electrode adapted to be secured to and in electrical contact with the patient'"'"'s body and which is coupled to a ground lead;

wherein the ablation actuator which includes a radio-frequency current source which is adapted to couple to both the ground lead and also to the conductive lead; and

wherein a radio-frequency ablation circuit is formed upon actuation, the radio-frequency ablation circuit including the radiofrequency current source, the conductive lead, the circumferential ablation electrode, the patient'"'"'s body, the return electrode, and the ground lead.

6. The circumferential ablation device assembly of claim 2, wherein the expandable member forms an outer skin of a conductive fluid chamber that is coupled to a fluid passageway which extends proximally along the elongate body and terminates proximally in a proximal fluid port in the region of the proximal end portion of the elongate member, the proximal fluid port being adapted to couple to a pressurizeable conductive fluid source, and

wherein the circumferential ablation electrode further comprises a porous membrane along the equatorial band which is adapted to pass electrically conductive fluid from the conductive fluid chamber and into tissue adjacent to the equatorial band.

7. The circumferential ablation device assembly of claim 6, wherein the porous membrane is disposed substantially along the working length and includes first and second membrane end portions with a middle membrane portion extending therebetween along the longitudinal axis, and further comprising:

an insulator disposed on each of the first and second membrane end portions and which is adapted to block the passage of conductive fluid from the conductive fluid chamber and through the porous membrane into surrounding tissue,

wherein only the middle membrane portion is uninsulated and is adapted to pass electrically conductive fluids from the conductive fluid chamber and into tissue adjacent to the middle membrane portion, the middle membrane portion thereby forming the equatorial band.

8. The circumferential ablation device assembly of claim 6, further comprising

a pressurizeable conductive fluid source which includes a fluid reservoir that contains an electrically conductive fluid, the pressurizeable conductive fluid source being adapted to fluidly couple to the fluid passageway in order to fill and pressurize the conductive fluid chamber with the electrically conductive fluid and thereby force the electrically conductive fluid through the porous membrane and into surrounding tissue;

a return electrode adapted to be secured to and in electrical contact with the patient'"'"'s body and which is coupled to a ground lead; and

an ablation actuator which is a radio-frequency current source and which is adapted to electrically couple to both the conductive fluid in the fluid passageway and also to the ground lead;

wherein a radio-frequency ablation circuit is formed upon actuation of the ablation actuator, the radio-frequency ablation circuit including the radiofrequency current source, a volume of electrically conductive fluid contained within the fluid passageway and flowing through the porous membrane into surrounding tissue, the patient'"'"'s body, the return electrode, and the ground lead.

9. The circumferential ablation device assembly of claim 1, wherein the circumferential ablation element further comprises a thermal conductor located along the equatorial band and which is adapted to emit thermal energy into tissue adjacent to the equatorial band when the thermal conductor is coupled to and actuated by a thermal ablation actuator.

10. The circumferential ablation device assembly of claim 9, wherein the thermal conductor is disposed substantially along an outer surface of the working length of the expandable member and includes first and second conductor end portions with a middle conductor portion extending therebetween along the longitudinal axis, and further comprising:

a thermal insulator disposed on each of the first and second conductor end portions, such that only the middle conductor portion is uninsulated and thermally exposed to adjacent tissue such that the middle conductor portion thereby forms the equatorial band.

11. The circumferential ablation device assembly of claim 9, wherein the thermal conductor further comprises an electrical conductor located along the equatorial band and which is adapted to resistively heat and emit thermal energy when coupled to and actuated by a thermal ablation actuator which includes an electrical current source.

12. The circumferential ablation device assembly of claim 9, wherein the thermal conductor is adapted to be conductively heated and thereby emit thermal energy when coupled to and actuated by the thermal ablation actuator, said thermal ablation actuator comprising a thermal energy source.

13. The circumferential ablation device assembly of claim 12, wherein the expandable member further comprises an inflatable balloon which forms a balloon chamber that is coupled to a fluid passageway which extends along the longitudinal axis of the elongate body and terminates in a proximal inflation port in the region of the proximal end portion of the elongate body, the proximal inflation port being adapted to couple to a pressurizeable fluid source, the thermal conductor being located on an outer surface of the inflatable balloon;

and

wherein the thermal energy source comprises a heater element adapted to heat fluid within the fluid passageway, and wherein the heated fluid in the fluid passageway heats the thermal conductor which in turn emits heat into tissue surrounding the equatorial band.

14. The circumferential ablation device assembly of claim 1, wherein the working length of the expandable member when adjusted to the radially expanded position is adapted to conform to a pulmonary vein ostium.

15. The circumferential ablation device assembly of claim 14, wherein the working length of the expandable member has a shape when in the radially expanded position that includes a taper with a distally reducing outer diameter from a proximal region to a distal region.

16. The circumferential ablation device assembly of claim 15, wherein the equatorial band is located along the taper in the proximal region.

17. The circumferential ablation device assembly of claim 14, wherein the expandable member comprises an inflatable balloon which is coupled to a fluid passageway which extends proximally along the longitudinal axis of the elongate member and terminates in a proximal inflation port in the region of the proximal end portion of the elongate member, the proximal inflation port being adapted to couple to a pressurizeable fluid source,

the inflatable balloon further comprising a compliant balloon material and being adapted to conform to the pulmonary vein ostium when the working length is expanded to the radially expanded position in the left atrium and the expandable member is thereafter forced retrogradedly against the pulmonary vein wall in the region of the pulmonary vein ostium.

18. The circumferential ablation device assembly of claim 17, wherein the compliant balloon material is selected from the group of materials consisting of silicone, latex rubber, and polyvinyl chloride.

19. The circumferential ablation device assembly of claim 1, wherein the working length of the expandable member is adjustable between a plurality of radially expanded positions, wherein the plurality of radially expanded positions includes a range of expanded outer diameters in the region of the equatorial band, and wherein the equatorial band is adapted to ablate a continuous circumferential lesion pattern in tissue surrounding the equatorial band over the range of expanded outer diameters.

20. The circumferential ablation device assembly of claim 19, wherein the equatorial band further comprises a secondary shape relative to the longitudinal axis which defines an equatorial band width relative to the longitudinal axis, the secondary shape being adapted such that the equatorial band length shortens as the circumference of the equatorial band increases when the working length is expanded to a radially expanded position.

21. The circumferential ablation device assembly of claim 20, wherein the secondary shape is selected from the group of shapes consisting of a serpentine shape and a sawtooth shape.

22. The circumferential ablation device assembly of claim 19, wherein the equatorial band comprises a plurality of individual ablation elements positioned in a circumferentially spaced arrangement about the longitudinal axis, each said individual ablation element comprising a long axis and a short axis, the long axis having two opposite end portions, each said individual ablation element also being positioned with its long axis skewed at an angle relative to the longitudinal axis, and each end portion of each said individual ablation element being positioned to form a circumferential overlap region with another end portion of another adjacent individual ablation element;

and

whereby adjusting the working length between two radially expanded positions and thereby adjusting the equatorial band between two outer diameters, the position of each individual ablation element is adjusted relative to each adjacent individual ablation element such that the circumferential overlap regions between adjacent individual ablation elements are reduced although maintained.

23. The circumferential ablation device assembly of claim 19, wherein the expandable member when adjusted to one of the radially expanded positions is adapted to conform to a pulmonary vein ostium located along a left atrial wall.

24. The circumferential ablation device assembly of claim 23, wherein the working length has a shape when in one of the radially expanded positions which comprises a taper with a distally reducing outer diameter from a proximal region to a distal region.

25. The circumferential ablation device assembly of claim 24, wherein the equatorial band is located along the taper in the proximal region.

26. The circumferential ablation device assembly of claim 23, wherein the expandable member comprises an inflatable balloon that forms a portion of a fluid passageway which extends proximally along the longitudinal axis and terminates in a proximal inflation port in the region of the proximal end portion of the elongate member, the proximal inflation port being adapted to couple to a pressurizeable fluid source, and

wherein the inflatable balloon comprises a compliant balloon material which is adapted to conform to the pulmonary vein ostium when advanced retrogradedly from a left atrium into the pulmonary vein and is forced against the ostium.

27. The circumferential ablation device assembly of claim 26, wherein the compliant balloon material is selected from the group of materials consisting of silicone, latex rubber, and polyvinyl chloride.

28. The circumferential ablation device assembly of claim 1, wherein the equatorial band width is less than two-thirds of the working length of the expandable member.

29. The circumferential ablation device assembly of claim 1, wherein the equatorial band width is less than two-thirds of the circumference of the equatorial band when the working length is adjusted to the radially expanded position.

30. The circumferential ablation device assembly of claim 1, wherein the distal end portion of the elongate member further comprises a linear ablation member which has an elongate ablation element length and a linear ablation element, said linear ablation member being adapted to form a continuous linear lesion in tissue adjacent thereto when the linear ablation element is coupled to an ablation actuator.

31. The circumferential ablation device assembly of claim 30, wherein the linear ablation element further comprises an electrode which is coupled to an electrical conductor which has a proximal conductor end in the region of the proximal end portion that is adapted to couple to an ablation actuator which is an electrical current source.

32. The circumferential ablation device assembly of claim 30, wherein the linear ablation element further comprises a plurality of spaced electrodes, each electrode being coupled to an electrical conductor which has a proximal conductor end in the region of the proximal end portion that is adapted to couple to an ablation actuator which is an electrical current source.

33. The circumferential ablation device assembly of claim 30, wherein the linear ablation member further comprises first and second linear ablation member ends, the first linear ablation member end being located adjacent to the expandable member which forms at least in part a first anchor adapted to secure the first linear ablation member end in the region of a pulmonary vein ostium along a left atrium wall, the assembly further comprising:

a second anchor adjacent to the second linear ablation member end which is adapted to secure the second linear ablation member end to a second location along the left atrium wall,

wherein the linear ablation member is adapted to be secured to the left atrium wall between the first and second anchors when the anchors are secured to the first and second locations, respectively, such that a long linear lesion may be formed along a length of left atrial wall tissue located adjacent to the linear ablation element when the linear ablation element is coupled to an ablation actuator.

34. The circumferential ablation device assembly of claim 33, wherein each of the first and second anchors further comprises a guidewire tracking member which forms a bore having first and second guidewire ports and which is adapted to track over a guidewire which is slideably received into the bore through the first and second guidewire ports.

36. The circumferential ablation device assembly of claim 35, wherein the equatorial band further comprises a secondary shape relative to the longitudinal axis which defines an equatorial band width relative to the longitudinal axis, the secondary shape being adapted such that the equatorial band width shortens as the circumference of the equatorial band increases when the working length is expanded to a radially expanded position.

37. The circumferential ablation device assembly of claim 36, wherein the secondary shape is selected from the group of shapes consisting of a serpentine shape and a sawtooth shape.

38. The circumferential ablation device assembly of claim 35, wherein the equatorial band comprises a plurality of individual ablation elements positioned in a circumferentially spaced arrangement about the longitudinal axis, each said individual ablation element comprising a long axis and a short axis, the long axis having two opposite end portions, each said individual ablation element also being positioned with its long axis skewed at an angle relative to the longitudinal axis, and each end portion of each said individual ablation element being positioned to form a circumferential overlap region with another end portion of another adjacent individual ablation element;

and

whereby adjusting the working length between two radially expanded positions and thereby adjusting the equatorial band between two outer diameters, the position of each individual ablation element is adjusted relative to each adjacent individual ablation element such that the circumferential overlap regions between adjacent individual ablation elements are reduced although maintained.

39. The circumferential ablation device assembly of claim 35, wherein the expandable member when adjusted to one of the radially expanded positions is adapted to conform to a pulmonary vein ostium located along a left atrial wall.

40. The circumferential ablation device assembly of claim 39, wherein the working length has a shape when in one of the radially expanded positions which comprises a taper with a distally reducing outer diameter from a proximal region to a distal region.

41. The circumferential ablation device assembly of claim 40, wherein the equatorial band is located along the taper in the proximal region.

42. The circumferential ablation device assembly of claim 39, wherein the expandable member comprises an inflatable balloon that forms a portion of a fluid passageway which extends proximally along the longitudinal axis and terminates in a proximal inflation port in the region of the proximal end portion of the elongate member, the proximal inflation port being adapted to couple to a pressurizeable fluid source, and wherein the inflatable balloon comprises a compliant balloon material which is adapted to conform to the pulmonary vein ostium when advanced retrogradedly from a left atrium into the pulmonary vein and is forced against the ostium.

43. The circumferential ablation device assembly of claim 42, wherein the compliant balloon material is selected from the group of materials consisting of silicone, latex rubber, and polyvinyl chloride.

44. The circumferential ablation device assembly of claim 39, wherein the distal end portion of the elongate member further comprises a linear ablation member which has an elongate ablation element length and a linear ablation element and which is adapted to form a continuous linear lesion in tissue adjacent thereto when the linear ablation element is coupled to an ablation actuator.

45. The circumferential ablation device assembly of claim 44, wherein the linear ablation element further comprises an electrode which is coupled to an electrical conductor which has a proximal conductor end in the region of the proximal end portion that is adapted to couple to an ablation actuator which is an electrical current source.

46. The circumferential ablation device assembly of claim 44, wherein the linear ablation element further comprises a plurality of spaced electrodes, each electrode being coupled to an electrical conductor which has a proximal conductor end in the region of the proximal end portion that is adapted to couple to an ablation actuator which is an electrical current source.

47. The circumferential ablation device assembly of claim 44, wherein the linear ablation member further comprises first and second linear ablation member ends, the first linear ablation member end being located adjacent to the expandable member which forms at least in part a first anchor adapted to secure the first linear ablation member end in the region of a pulmonary vein ostium along a left atrium wall, the assembly further comprising:

a second anchor adjacent to the second linear ablation member end which is adapted to secure the second linear ablation member end to a second location along the left atrium wall,

wherein the linear ablation member is adapted to be secured to the left atrium wall between the first and second anchors when the anchors are secured to the first and second locations, respectively, such that a long linear lesion may be formed along a length of left atrial wall tissue located adjacent to the linear ablation element when the linear ablation element is coupled to an ablation actuator.

48. The circumferential ablation device assembly of claim 47, wherein each of the first and second anchors further comprises a guidewire tracking member which forms a bore having first and second guidewire ports and which is adapted track over a guidewire which is slideably received into the bore through the first and second guidewire ports.

49. The circumferential ablation device assembly of claim 35, wherein the distal end portion of the elongate member further comprises a linear ablation member which has an elongate ablation element length and a linear ablation element, said linear ablation member being adapted to form a continuous linear lesion in tissue adjacent thereto when the linear ablation element is coupled to an ablation actuator.

50. The circumferential ablation device assembly of claim 49, wherein the linear ablation element further comprises an electrode which is coupled to an electrical conductor which has a proximal conductor end in the region of the proximal end portion that is adapted to couple to an ablation actuator which is an electrical current source.

51. The circumferential ablation device assembly of claim 49, wherein the linear ablation element further comprises a plurality of spaced electrodes, each electrode being coupled to an electrical conductor which has a proximal conductor end in the region of the proximal end portion that is adapted to couple to an ablation actuator which is an electrical current source.

52. The circumferential ablation device assembly of claim 49, wherein the linear ablation member further comprises first and second linear ablation member ends, the first linear ablation member end being located adjacent to the expandable member which forms at least in part a first anchor adapted to secure the first linear ablation member end in the region of a pulmonary vein ostium along a left atrium wall, the assembly further comprising:

a second anchor adjacent to the second linear ablation member end which is adapted to secure the second linear ablation member end to a second location along the left atrium wall,

wherein the linear ablation member is adapted to be secured to the left atrium wall between the first and second anchors when the anchors are secured to the first and second locations, respectively, such that a long linear lesion may be formed along a length of left atrial wall tissue located adjacent to the linear ablation element when the linear ablation element is coupled to an ablation actuator.

53. The circumferential ablation device assembly of claim 52, wherein each of the first and second anchors further comprises a guidewire tracking member which forms a bore having first and second guidewire ports and which is adapted track over a guidewire which is slideably received into the bore through the first and second guidewire ports.

35. A circumferential ablation device assembly for ablating a circumferential lesion in a body space wall which defines at least a portion of a body space, comprising:

an elongate body with a proximal end portion and a distal end portion and a longitudinal axis that extends between the proximal and distal end portions;

an expandable member located in the region of the distal end portion and having a working length along the longitudinal axis which is adjustable between a radially collapsed position and a plurality of radially expanded positions which correspond to a range of outer diameters along the working length, the range of outer diameters being larger than a collapsed outer diameter of the expandable member when in the radially collapsed position;

an expansion actuator which is coupled to the expandable member and which is adapted to adjust the expandable member from the radially collapsed position to any one of the radially expanded positions; and

a circumferential ablation element which is coupled to the working length of the expandable member and which, when coupled to and actuated by an ablation actuator, is adapted to ablate a circumferential region of tissue adjacent to the working length, wherein the circumferential region of tissue is continuous along a circumference of the body space wall to thereby circumscribe the body space.

54. A circumferential ablation device assembly for ablating a circumferential lesion in a body space wall which defines at least a portion of a body space, comprising:

an elongate body with a proximal end portion and a distal end portion and a longitudinal axis that extends between the proximal and distal end portions;

an expandable member located in the region of the distal end portion and having a working length along the longitudinal axis which is adjustable between a radially collapsed position and a radially expanded position which has an outer diameter which is larger when in the radially expanded position than when in the radially collapsed position, the working length also being adapted to conform to the pulmonary vein ostium when in the radially expanded position;

an expansion actuator which is coupled to the expandable member and which is adapted to adjust the expandable member from the radially collapsed position to the radially expanded position; and

a circumferential ablation element which is coupled to the working length of the expandable member and which, when coupled to and actuated by an ablation actuator, is adapted to ablate a circumferential region of tissue adjacent to the working length and which circumscribes the body space.

55. The circumferential ablation device assembly of claim 54, wherein the working length of the expandable member has a shape when in the radially expanded position that includes a taper with a distally reducing outer diameter from a proximal region to a distal region.

56. The circumferential ablation device assembly of claim 54, wherein the expandable member comprises an inflatable balloon which is coupled to a fluid passageway which extends proximally along the longitudinal axis of the elongate member and terminates in a proximal inflation port in the region of the proximal end portion of the elongate member, the proximal inflation port being adapted to couple to a pressurizeable fluid source,

the inflatable balloon further comprising a compliant balloon material and being adapted to conform to the pulmonary vein ostium when the working length is expanded to the radially expanded position in the left atrium and the expandable member is thereafter forced retrogradedly against the pulmonary vein wall in the region of the pulmonary vein ostium.

57. The circumferential ablation device assembly of claim 56, wherein the compliant balloon material is selected from the group of materials consisting of silicone, latex rubber, and polyvinyl chloride.

58. The circumferential ablation device assembly of claim 54, wherein the distal end portion of the elongate member further comprises a linear ablation member which has an elongate ablation element length and a linear ablation element which is adapted to form a continuous linear lesion in tissue adjacent thereto when the linear ablation element is coupled to an ablation actuator.

59. The circumferential ablation device assembly of claim 58, wherein the linear ablation element further comprises an electrode which is coupled to an electrical conductor which has a proximal conductor end in the region of the proximal end portion that is adapted to couple to the ablation actuator which is an electrical current source.

60. The circumferential ablation device assembly of claim 58, wherein the linear ablation element further comprises a plurality of spaced electrodes, each electrode being coupled to an electrical conductor which has a proximal conductor end in the region of the proximal end portion that is adapted to couple to the ablation actuator which is an electrical current source.

61. The circumferential ablation device assembly of claim 58, wherein the linear ablation member further comprises first and second linear ablation member ends, the first linear ablation member end being located adjacent to the expandable member which forms at least in part a first anchor adapted to secure the first linear ablation member end in the region of a pulmonary vein ostium along a left atrium wall, the assembly further comprising:

a second anchor adjacent to the second linear ablation member end which is adapted to secure the second linear ablation member end to a second location along the left atrium wall,

wherein the linear ablation member is adapted to be secured to the left atrium wall between the first and second anchors when the anchors are secured to the first and second locations, respectively, such that a long linear lesion may be formed along a length of left atrial wall tissue located adjacent to the linear ablation element when the linear ablation element is coupled to the ablation actuator.

62. The circumferential ablation device assembly of claim 61, wherein each of the first and second anchors further comprises a guidewire tracking member which forms a bore having first and second guidewire ports and which is adapted track over a guidewire which is slideably received into the bore through the first and second guidewire ports.