CLAIMS We Claim:
1. A porous electrode assembly comprising a wall surrounding an interior area, a lumen capable of conveying a medium into an internal area, the area capable of holding a medium containing ions, an element coupling the medium within the interior area to a source of electrical energy, and at least a portion of the wall comprising a porous material sized to block passage of macromolecules while allowing passage of ions contained in the medium in the interior area to thereby enable ionic transport of electrical energy through the porous material to the exterior of the wall.
2. A porous electrode assembly comprising a wall surrounding an interior area capable of holding a medium containing ions under pressure, an element coupling the medium to a source of electrical energy, and at least a portion of the wall comprising a porous material sized to pass ions contained in the medium without substantial liquid perfusion through the porous material, to thereby enable ionic transport of electrical energy through the porous material to the exterior of the wall.
3. A porous electrode assembly comprising a wall surrounding an interior area capable of holding medium containing ions under
pressure, an element capable of coupling the medium to a source of electrical energy, and at least a portion of the wall comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy through the porous material to the exterior of the wall, the porous material having a bubble point value greater than the pressure in the interior area.
4. A porous electrode assembly comprising a wall surrounding an interior area capable of holding medium containing ions under pressure, an element coupling the medium to a source of electrical energy, and at least a portion of the wall comprising a hydrophilic porous material sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy through the porous material to the exterior of the wall, the porous material having a bubble point value greater than the pressure within the interior area, whereby ionic transport occurs substantially free of liquid perfusion through the porous material.
5. A porous electrode assembly according to claim 1 or 2 or 3 or 4 wherein the porous material comprises an ultrafiltration membrane.
6. A porous electrode assembly according to claim 1 or 2 or 3 or 4 wherein the element comprises an electrically conductive electrode in the interior area of the wall.
7. An assembly according to claim 6 wherein the electrically conductive electrode comprises a nobel metal.
8. An assembly according to claim 6 wherein the electrically conductive electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
9. An assembly according to claim 1 or 2 or 3 or 4 wherein the medium comprises a hypertonic solution.
10. An assembly according to claim 9 wherein the hypertonic solution includes sodium chloride.
11. An assembly according to claim 10 wherein the sodium chloride is present in a concentration at or near saturation.
12. An assembly according to claim 10 wherein the sodium chloride is present in a concentration of up to about 9% weight by volume.
13. An assembly according to claim 9 wherein the hypertonic solution includes potassium chloride.
14. An assembly according to claim 1 or 2 or 3 or 4 wherein the medium has a resistivity lower than about 150 ohm*cm.
15. An assembly according to claim 1 or 2 or 3 or 4 wherein the medium has a resistivity lower than about 10 ohm*cm.
16. An assembly according to claim l or 2 or 3 or 4
wherein the medium has a resistivity of about 5 ohm*cm.
17. An assembly according to claim 1 or 2 or 3 or 4 wherein the medium carries a radiopaque substance.
18. An assembly according to claim 1 or 2 or 3 or 4 wherein the porous material has an electrical resistivity of at least about 500 ohm*cm.
19. An assembly according to claim 1 or 2 or 3 or 4 wherein the porous material has an electrical resistivity less than about 500 ohm•cm.
20. An assembly according to claim 1 or 2 or 3 or 4 wherein at least a portion of the wall includes an electrically conductive material.
21. An assembly according to claim 20 wherein the electrically conductive material of the wall is porous.
22. An assembly according to claim 20 wherein the electrically conductive material of the wall is nonporous.
23. An assembly according to claim 20 wherein the electrically conductive material comprises a coating deposited on the wall.
24. An assembly according to claim 20 wherein the electrically conductive material comprises foil affixed to the wall.
25. An assembly according to claim 20 wherein the electrically conductive
material is located in the wall.
26. An assembly according to claim 20 wherein the electrically conductive material comprises noninsulated signal wire exposed on the exterior of the wall.
27. An electrode assembly according to claim 20 wherein at least a portion the wall is free of electrically conductive material.
28. An electrode assembly according to claim l or 2 or 3 or 4 wherein at least a portion the wall is free of electrically conductive material.
29. An assembly according to claim 1 or 2 or 3 or 4 and further including members assembled within the interior area to form a support structure underlying the wall.
30. An assembly according to claim 29 wherein the solid support members are made from metal material.
31. An assembly according to claim 30 wherein the metal material includes nickel titanium.
32. An assembly according to claim 30 wherein the metal material includes stainless steel.
33. An assembly according to claim 29 wherein the solid support members are made from plastic material.
34. An assembly according to claim 29 wherein the solid support members comprise elongated spline elements assembled in a circumferentially spaced relationship.
35. An assembly according to claim 29
wherein the solid support members comprise a porous foam structure.
36. An assembly according to claim 1 or 2 or 3 or 4 wherein the wall includes a distal region and a proximal region, and wherein the porous material occupies more of the distal region than the proximal region.
37. An assembly according to claim 36 wherein at least l/3rd of the proximal region is free of porous material.
38. An assembly according to claim 36 wherein the porous material occupies at least l/3rd of the distal region.
39. An assembly according to claim 1 or 2 or 3 or 4 and further including a radiopaque material carried by the assembly.
40. A system for heating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, and
at least a portion of the wall comprising a porous material sized to block passage of macromolecules while allowing passage of ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to heat tissue located between the return electrode and the electrode.
41. A system for ablating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, and at least a portion of the wall comprising a porous material sized to block passage of macromolecules while allowing passage of ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to ablate tissue located between the return electrode and
the electrode.
42. A system for ablating heart tissue comprising a catheter tube having a distal end for deployment in a heart chamber, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through heart tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, and at least a portion of the wall comprising a porous material sized to block passage of macromolecules while allowing passage of ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to ablate heart tissue located between the return electrode and the electrode.
43. A system for heating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions,
an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, and at least a portion of the wall comprising a porous material sized to pass ions contained in the medium without substantial liquid perfusion through the porous material, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to heat tissue located between the return electrode and the electrode. 44. A system for ablating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically
conductive element to a source of energy to transmit the energy, and at least a portion of the wall comprising a porous material sized to pass ions contained in the medium without substantial liquid perfusion through the porous material, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to ablate tissue located between the return electrode and the electrode.
45. A system for ablating heart tissue comprising a catheter tube having a distal end for deployment in a heart chamber, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through heart tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, and at least a portion of the wall comprising a porous material sized to pass ions contained in the medium without substantial liquid perfusion through the porous material, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium
to the exterior of the wall for transmission to the return electrode to ablate heart tissue located between the return electrode and the electrode.
46. A system for heating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area subject to internal pressure, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, and at least a portion of the wall comprising a porous material sized to pass ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to heat tissue located between the return electrode and the electrode, the porous material having a bubble point value greater than the internal pressure.
47. A system for ablating body tissue comprising a catheter tube having a distal end,
a return electrode, a fluid source of a medium containing ions an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area subject to an internal pressure, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, and at least a portion of the wall comprising a porous material sized to pass ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to ablate tissue located between the return electrode and the electrode, the porous material having a bubble point value greater than the internal pressure.
48. A system for ablating heart tissue comprising a catheter tube having a distal end for deployment in a heart chamber, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through heart tissue, the electrode
comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area subject to an internal pressure, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, and at least a portion of the wall comprising a porous material sized to pass ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to ablate heart tissue located between the return electrode and the electrode, the porous material having a bubble point value greater than the internal pressure.
49. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 wherein the medium comprises a hypertonic solution.
50. A system according to claim 49 wherein the hypertonic solution includes sodium chloride.
51. A system according to claim 50 wherein the sodium chloride is present in a concentration at or near saturation.
52. A system according to claim 50 wherein the sodium chloride is present in a concentration of up to about 9% weight by volume.
53. A system according to claim 49 wherein the hypertonic solution includes
potassium chloride.
54. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 wherein the medium has a resistivity lower than about 150 ohm*cm.
55. A system according to claim 54 wherein the medium has a resistivity lower than about 10 ohm*cm.
56. A system according to claim 54 wherein the medium has a resistivity of about 5 ohm*cm.
57. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 wherein the porous material has an electrical resistivity of at least about 500 ohm•cm.
58. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 wherein the porous material has an electrical resistivity of less than about 500 ohm•cm.
59. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 wherein at least a portion of the wall includes an electrically conductive material.
60. A system according to claim 59 wherein the electrically conductive material of the wall is porous.
61. A system according to claim 59 wherein the electrically conductive material of the wall is nonporous.
62. A system according to claim 59 wherein at least a portion the wall is free of electrically conductive material.
63. A system according to claim 40 or 41
or 42 or 43 or 44 or 45 or 46 or 47 or 48 wherein at least a portion the wall is free of electrically conductive material.
64. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 wherein the wall includes a distal region and a proximal region, and wherein the ultraporous material occupies more of the distal region than the proximal region.
65. A system according to claim 64 wherein at least l/3rd of the proximal region is free of porous material.
66. A system according to claim 64 wherein the ultraporous material occupies at least l/3rd of the distal region.
67. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 and further including a radiopaque material carried by the electrode.
68. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 and further including a controller including means for specifying an electrical resistivity for the porous material based, at least in part, upon a desired physiological effect.
69. A system according to claim 41 or 42 or 44 or 45 or 47 or 48 and further including a controller including means for specifying a first electrical resistivity for the porous material to achieve a first tissue lesion characteristic and specifying a second electrical resistivity for the porous material different than the first electrical
resistivity to achieve a second tissue lesion characteristic different than the first lesion characteristic.
70. A system according to claim 42 or 45 or 48 and further including a controller for specifying a first electrical resistivity for the porous material to achieve a deep tissue lesion geometry and specifying a second electrical resistivity for the porous material greater than the first electrical resistivity to achieve a shallow tissue lesion geometry.
71. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 and further including a temperature sensing element carried by the electrode, and further including a controller including means for specifying transmission of energy to the medium based, at least in part, upon temperature sensed by the temperature sensing element.
72. A system according to claim 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 wherein the porous material is hydrophilic.
73. A porous electrode assembly comprising a structure having a wall comprising a distal region and a proximal region, the wall surrounding an interior area, the wall adapted to selectively assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter, the interior area capable of holding a
medium containing ions, an element for use with a source of electrical energy electrically coupling the medium contained within the interior area, and the wall including a porous section sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy from the source through the medium and porous section to the exterior of the wall, the porous section occupying more of the distal region of the wall than the proximal region.
74. A porous electrode assembly according to claim 73 wherein at least l/3rd of the proximal region of the wall is free of pores.
75. A porous electrode assembly according to claim 73 wherein the porous section comprises at least first and second porous zones spaced apart by a third zone free of pores.
76. A porous electrode assembly according to claim 75 wherein the structure includes an axis, and wherein the first and second porous zones are circumferentially spaced apart by the third zone about the axis.
77. A porous electrode assembly according to claim 75 wherein the structure includes an axis, and wherein the first and second porous zones are spaced apart by the third zone along the axis.
78. A porous electrode assembly according to claim 73
wherein the wall is electrically conductive.
79. A porous electrode assembly according to claim 73 and further including a radiopaque element carried by the structure.
80. A porous electrode assembly according to claim 73 wherein the medium carries a radiopaque contrast substance.
81. A porous electrode assembly according to claim 73 wherein the porous section has an electrical resistivity of at least about 500 ohm*cm.
82. A porous electrode assembly according to claim 73 wherein the porous section has an electrical resistivity of less than about 500 ohm*cm.
83. A porous electrode assembly according to claim 73 wherein the medium comprises a hypertonic solution.
84. A porous electrode assembly according to claim 83 wherein the hypertonic solution includes sodium chloride.
85. A porous electrode assembly according to claim 84 wherein the sodium chloride is present in a concentration at or near saturation.
86. A porous electrode assembly according to claim 84 wherein the sodium chloride is present in
a concentration of up to about 9% weight by volume.
87. A porous electrode assembly according to claim 84 wherein the hypertonic solution includes potassium chloride.
88. A porous electrode assembly according to claim 73 wherein at least l/3rd of the proximal region of the wall is free of pores.
89. A porous electrode assembly according to claim 73 wherein the element comprises an electrically conductive electrode carried within the interior area adapted to transmit electrical energy.
90. A porous electrode assembly according to claim 89 wherein the electrically conductive electrode comprises a nobel metal.
91. A porous electrode assembly according to claim 89 wherein the electrically conductive electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
92. A porous electrode assembly according to claim 73 wherein the porous section is hydrophilic.
93. A porous electrode assembly according to claim 92 wherein the medium occupies the interior area subject to interior pressure, wherein the porous section has a bubble
point value, and wherein the bubble point value exceeds the interior pressure.
94 A porous electrode assembly according to claim 73 wherein the porous section is hydrophobic.
95. A porous electrode assembly according to claim 94 wherein the medium occupies the interior area subject to interior pressure, wherein the porous section has a bubble point value, and wherein the bubble point value is equal to or less than the interior pressure.
96. A porous electrode assembly according to claim 73 wherein the medium occupies the interior area subject to interior pressure, wherein the porous section has a bubble point value, and wherein the bubble point value exceeds the interior pressure.
97. A porous electrode assembly according to claim 73 wherein the medium occupies the interior area subject to interior pressure, wherein the porous section has a bubble point value, and wherein the bubble point value is equal to or less than the interior pressure.
98. A porous electrode assembly according to claim 73 wherein the porous section includes a hydrophilic coating.
99. A porous electrode assembly according to claim 73 wherein the wall is hydrophobic, and wherein the porous section includes a hydrophilic coating.
100. A porous electrode assembly according to claim 73 wherein the porous section comprises an ultraporous material.
101. A porous electrode assembly according to claim 73 wherein the porous section comprises a microporous material.
102. A system for heating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, a porous electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the porous electrode comprising a wall comprising a distal region and a proximal region, the wall surrounding an interior area, the wall adapted to selectively assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter, and a lumen communicating with the interior area and the fluid source to convey into the interior area the medium containing ions, the wall including a porous section sized to pass ions contained in the medium, the porous section occupying more of the distal region of the wall than the proximal region, and
means for coupling the medium within the interior area to a source of electrical energy, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to heat tissue located between the return electrode and the porous electrode.
103. A system for ablating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, a porous electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the porous electrode comprising a wall comprising a distal region and a proximal region, the wall having an exterior peripherally surrounding an interior area, the wall adapted to selectively assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter, and a lumen communicating with the interior area and the fluid source to convey into the interior area the medium containing ions, the wall including a porous section sized to pass ions contained in the medium, the porous section occupying more of the distal region of the wall than the proximal region, and means for coupling the medium within the interior area to a source of electrical energy, thereby establishing ionic transport of electrical energy from the electrically conductive element
through the medium to the exterior of the wall for transmission to the return electrode to ablate tissue located between the return electrode and the porous electrode.
104. A system for ablating heart tissue comprising a catheter tube having a distal end for deployment in a heart chamber, a return electrode, a fluid source of a medium containing ions, a porous electrode on the distal end of the catheter tube electrically coupled to the return electrode through heart tissue, the porous electrode comprising a wall comprising a distal region and a proximal region, the wall having an exterior peripherally surrounding an interior area, the wall adapted to selectively assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter, and a lumen communicating with the interior area and the fluid source to convey into the interior area the medium containing ions, the wall including a porous section sized to pass ions contained in the medium, the porous section occupying more of the distal region of the wall than the proximal region, and means for coupling the medium within the interior area to a source of electrical energy, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to ablate heart tissue located between the return electrode
and the porous electrode.
105. A system according to claim 93 or 94 or 95 wherein at least l/3rd of the proximal region of the wall is free of pores.
106. A system according to claim 102 or 103 or 104 wherein the porous section comprises at least first and second porous zones spaced apart by a third zone free of pores.
107. A system according to claim 106 wherein the structure includes an axis, and wherein the first and second porous zones are circumferentially spaced apart by the third zone about the axis.
108. A system according to claim 106 wherein the structure includes an axis, and wherein the first and second porous zones are spaced apart by the third zone along the axis.
109. A system according to claim 102 or 103 or 104 wherein the wall is electrically conductive.
110. A system according to claim 102 or 103 or 104 and further including a radiopaque element carried by the structure.
111. A system according to claim 102 or 103 or 104 wherein the medium carries a radiopaque contrast substance.
112. A system according to claim 102 or 103 or 104
wherein the porous section has an electrical resistivity of at least about 500 ohm•cm.
113. A system according to claim 102 or 103 or 104 wherein the porous section has an electrical resistivity of less than about 500 ohm•cm.
114. A system according to claim 102 or 103 or 104 wherein the medium comprises a hypertonic solution.
115. A system according to claim 114 wherein the hypertonic solution includes sodium chloride.
116. A system according to claim 115 wherein the sodium chloride is present in a concentration at or near saturation.
117. A system according to claim 115 wherein the sodium chloride is present in a concentration of up to about 9% weight by volume.
118. A system according to claim 102 or 103 or 104 wherein the hypertonic solution includes potassium chloride.
119. A system according to claim 102 or 103 or 104 wherein the medium has a resistivity lower than about 150 ohm*cm.
120. A system according to claim 119 wherein the medium has a resistivity lower than about 10 ohm*cm.
121. A system according to claim 119 wherein the medium has a resistivity
lower than about 5 ohm*cm.
122. A system according to claim 102 or 103 or 104 wherein the medium includes a material whose presence increases viscosity of the medium.
123. A system according to claim 102 or 103 or 104 wherein the medium includes at least one ionic material whose presence increases viscosity of the medium.
124. A system according to claim 113 wherein the at least one ionic material comprises a radiopaque substance.
125. A system according to claim 102 or 103 or 104 wherein the medium includes a nonionic material whose presence increases viscosity of the medium.
126. A system according to claim 125 wherein the nonionic material includes glycerol.
127. A system according to claim 125 wherein the nonionic material includes mannitol.
128. A system according to claim 102 or 103 or 104 wherein the porous section comprises an ultraporous material.
129. A system according to claim 102 or 103 or 104 wherein the porous section comprises a microporous material.
130. A system according to claim 102 or 103 or 104 and further including a controller
including means for specifying ionic transport through the porous section at a desired rate based, at least in part, upon a desired physiological effect.
131. A system according to claim 130 wherein the controller includes means for specifying a pressure difference across the porous section to achieve a desired rate of liquid perfusion based, at least in part, upon the desired physiological effect.
132. A system according to claim 130 wherein the controller includes means for specifying constituting the medium to have a desired viscosity based, at least in part, upon the desired physiological effect.
133. A system according to claim 102 or 103 or 104 and further including a controller including means for specifying an electrical resistivity for the porous section based, at least in part, upon a desired physiological effect.
134. A system according to claim 103 or 104 and further including a controller including means for specifying a first electrical resistivity for the porous section to achieve a first tissue lesion characteristic and specifying a second electrical resistivity for the porous section different than the first electrical resistivity to achieve a second tissue lesion characteristic different than the first lesion characteristic.
135. A system according to claim 103 or 104 and further including a controller for
specifying a first electrical resistivity for the porous section to achieve a deep tissue lesion geometry and specifying a second electrical resistivity for the porous section greater than the first electrical resistivity to achieve a shallow tissue lesion geometry.
136. A system according to claim 102 or 103 or 104 and further including a temperature sensing element carried by the electrode, and further including a controller including means for specifying delivery of electrical energy to the medium based, at least in part, upon temperature sensed by the temperature sensing element.
137. A system according to claim 102 or 103 or 104 wherein the porous section is hydrophilic.
138. A system according to claim 137 wherein the medium occupies the interior area subject to interior pressure, wherein the porous section has a bubble point value, and wherein the bubble point value exceeds the interior pressure.
139. A system according to claim 102 or 103 or 104 wherein the porous section is hydrophobic.
140. A system according to claim 139 wherein the medium occupies the interior area subject to interior pressure, wherein the porous section has a bubble point value, and
wherein the bubble point value is equal to or less than the interior pressure.
141. A system according to claim 102 or 103 or 104 wherein the medium occupies the interior area subject to interior pressure, wherein the porous section has a bubble point value, and wherein the bubble point value exceeds the interior pressure.
142. A system according to claim 102 or 103 or 104 wherein the medium occupies the interior area subject to interior pressure, wherein the porous section has a bubble point value, and wherein the bubble point value is equal to or less than the interior pressure.
143. A system according to claim 102 or 103 or 104 wherein the porous section includes a hydrophilic coating.
144. A system according to claim 102 or 103 or 104 wherein the wall is hydrophobic, and wherein the porous section includes a hydrophilic coating.
145. A system according to claim 102 or 103 or 104 wherein the porous section comprises an ultraporous material.
146. A system according to claim 102 or 103 or 104 wherein the porous section comprises a microporous material.
147. A porous electrode assembly comprising a wall surrounding an interior area, a lumen capable of conveying a medium into the interior area, the interior area capable of holding medium containing ions, an element capable of coupling the medium within the interior area to a source of electrical energy, and the wall including at least two spaced apart zones each comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy from the source through the medium and porous material to the exterior of the wall.
148. A porous electrode assembly comprising a wall surrounding an interior area capable of holding a medium containing ions, an element capable of coupling the medium to a source of electrical energy, and the wall including at least two spaced apart zones each comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy from the source through the medium and porous material to the exterior of the wall.
149. A porous electrode assembly comprising a wall surrounding an interior area, a generator of radio frequency energy, a fluid source holding a medium containing ions, a lumen communicating with the interior area and the fluid source to convey into the
interior area the medium containing ions, an element capable of being coupled to the generator to establish electrical contact between the medium within the interior area and the generator, and the wall including at least two spaced apart zones each comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of radio frequency energy from the generator through the medium and porous material to the exterior of the wall.
150. A porous electrode assembly comprising a wall surrounding an interior area, an element capable of coupling the medium within the interior area, the area capable of holding a medium containing ions to a source of electrical energy, the wall including at least two spaced apart zones each comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy from the source through the medium and porous material to the exterior of the wall, and bladders in the interior area aligned in operative association with the spaced apart zones capable of holding medium in contact with the porous material/ and a lumen communicating with each bladder capable of conveying a medium containing ions into the respective bladder.
151. An assembly according to claim 147 or 148 or 149 or 150 wherein the at least two zones are spaced apart by a third zone comprising a material that
blocks passage of ions contained in the medium.
152. An assembly according to claim 147 or 148 or 149 or 150 wherein the wall extends about an axis, and wherein the first and second zones are circumferentially spaced apart about the axis.
153. An assembly according to claim 147 or 148 or 149 or 150 wherein the wall extends about an axis, and wherein the first and second zones are spaced apart along the axis.
154. An assembly according to claim 147 or 148 or 149 or 150 wherein the wall includes a distal region and a proximal region, and wherein the porous material occupies more of the distal region than the proximal region.
155. An assembly according to claim 154 wherein at least l/3rd of the proximal region is free of porous material.
156. An assembly according to claim 154 wherein the porous material occupies at least l/3rd of the distal region.
157. An assembly according to claim 147 or 148 or 149 or 150 wherein the wall is adapted to selectively assume an expanded geometry having a first maximum diameter and a collapsed geometry having a second maximum diameter less than the first maximum diameter.
158. An assembly according to claim 157 and further including at least one folding region on the exterior of the wall adapted
to fold upon itself along a predefined fold line as geometry changes.
159. An assembly according to claim 157 wherein the fold line is located generally between the two zones.
160. An assembly according to claim 157 wherein the folding region is not porous to pass ions.
161. An assembly according to claim 157 wherein the folding region is essentially free of electrically conducting material.
162. An assembly according to claim 147 or 148 or 149 or 150 and further including at least one temperature sensing element carried by the wall.
163. An assembly according to claim 162 wherein the at least one temperature sensing element is located proximate to at least one of the zones of porous material.
164. An assembly according to claim 162 wherein the at least one temperature sensing element is located in at least one of the zones of porous material.
165. An assembly according to claim 162 wherein the zones of porous material have edge boundaries, and wherein the at least one temperature sensing element is located along at least one of the edge boundaries.
166. An assembly according to claim 147 or 148 or 149 or 150 wherein the porous material is sized to block passage of blood cells while allowing passage of ions.
167. An assembly according to claim 147
or 148 or 149 or 150 wherein the porous material is sized to block passage of macromolecules while allowing passage of ions.
168. An assembly according to claim 147 or 148 or 149 or 150 wherein the porous material comprises an ultrafiltration membrane.
169. An assembly according to claim 147 or 148 or 149 or 150 wherein the porous material comprises a microporous membrane.
170. An assembly according to claim 147 or 148 or 149 or 150 wherein the element comprises an electrically conductive electrode in the interior area of the wall.
171. An assembly according to claim 170 wherein the electrically conductive electrode comprises a nobel metal.
172. An assembly according to claim 170 wherein the electrically conductive electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
173. An assembly according to claim 147 or 148 or 149 or 150 wherein the medium comprises a hypertonic solution.
174. An assembly according to claim 173 wherein the hypertonic solution includes sodium chloride.
175. An assembly according to claim 173 wherein the sodium chloride is present in a concentration at or near saturation.
176. An assembly according to claim 173 wherein the sodium chloride is present in a concentration of up to about 9% weight by volume.
177. An assembly according to claim 173 wherein the hypertonic solution includes potassium chloride.
178. An assembly according to claim 147 or 148 or 149 or 150 wherein the medium has a resistivity lower than about 150 ohm*cm.
179. An assembly according to claim 178 wherein the medium has a resistivity lower than about 10 ohm-cm.
180. An assembly according to claim 178 wherein the medium has a resistivity of about 5 ohm*cm.
181. An assembly according to claim 147 or 148 or 149 or 150 wherein the medium includes a material whose presence increases viscosity of the medium.
182. An assembly according to claim 147 or 148 or 149 or 150 wherein the medium includes at least one ionic material whose presence increases viscosity of the medium.
183. An assembly according to claim 182 wherein the at least one ionic material comprises a radiopaque substance.
184. An assembly according to claim 147 or 148 or 149 or 150 wherein the medium includes a nonionic material whose presence increases viscosity of the medium.
185. An assembly according to claim 184
wherein the nonionic material includes glycerol.
186. An assembly according to claim 184 wherein the nonionic material includes mannitol.
187. An assembly according to claim 147 or 148 or 149 or 150 wherein the porous material has an electrical resistivity of at least about 500 ohm•cm.
188. An assembly according to claim 147 or 148 or 149 or 150 wherein the porous material has an electrical resistivity less than about 500 ohm*cm.
189. An assembly according to claim 147 or 148 or 149 or 150 wherein at least a portion of the wall includes an electrically conductive material.
190. An assembly according to claim 189 wherein the electrically conductive material of the wall is porous to pass ions.
191. An assembly according to claim 189 wherein the electrically conductive material of the wall is nonporous to ions.
192. An assembly according to claim 189 wherein the electrically conductive material comprises a coating deposited on the wall.
193. An assembly according to claim 189 wherein the electrically conductive material comprises foil affixed to the wall.
194. An assembly according to claim 189 wherein the electrically conductive material is located in the wall.
195. An assembly according to claim 189
wherein the electrically conductive material comprises noninsulated signal wire exposed on the exterior of the wall.
196. An electrode assembly according to claim 189 wherein at least a portion the wall is free of electrically conductive material.
197. An electrode assembly according to claim 147 or 148 or 149 or 150 wherein at least a portion the wall is free of electrically conductive material.
198. An assembly according to claim 147 or 148 or 149 or 150 and further including members assembled within the interior area to form a support structure underlying the wall.
199. An assembly according to claim 198 wherein the solid support members are made from metal material.
200. An assembly according to claim 199 wherein the metal material includes nickel titanium.
201. An assembly according to claim 199 wherein the metal material includes stainless steel.
202. An assembly according to claim 198 wherein the solid support members are made from plastic material.
203. An assembly according to claim 198 wherein the solid support members comprise elongated spline elements assembled in a circumferentially spaced relationship.
204. An assembly according to claim 198 wherein the solid support members comprise a porous foam structure.
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or 148 or 149 or 150 wherein the medium occupies the interior area subject to interior pressure, wherein the porous material has a bubble point pressure value, and wherein the bubble point pressure value is equal to or less than the interior pressure.
212. An assembly according to claim 147 or 148 or 149 or 150 wherein the porous material includes a hydrophilic coating.
213. An assembly according to claim 147 or 148 or 149 or 150 wherein the wall is hydrophobic, and wherein the porous material includes a hydrophilic coating.
214. A system for heating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, the wall including at least two spaced apart zones each comprising a porous material
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205. An assembly according to claim 147 or 148 or 149 or 150 and further including a radiopaque material carried by the assembly.
206. An assembly according to claim 147 or 148 or 149 or 150 wherein the porous material is hydrophilic.
207. An assembly according to claim 206 wherein the medium occupies the interior area subject to interior pressure, wherein the porous material has a bubble point pressure value, and wherein the bubble point pressure value exceeds the interior pressure.
208. An assembly according to claim 147 or 148 or 149 or 150 wherein the porous material is hydrophobic.
209. An assembly according to claim 208 wherein the medium occupies the interior area subject to interior pressure, wherein the porous material has a bubble point pressure value, and wherein the bubble point pressure value is equal to or less than the interior pressure.
210. An assembly according to claim 147 or 148 or 149 or 150 wherein the medium occupies the interior area subject to interior pressure, wherein the porous material has a bubble point pressure value, and wherein the bubble point pressure value exceeds the interior pressure.
211. An assembly according to claim 147
sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy from the source through the medium and porous material to the exterior of the wall for transmission to the return electrode to heat tissue located between the return electrode and the electrode, and a controller coupled to fluid source and the source of energy to control transport of electrical energy by the spaced apart zones according to preestablished criteria.
215. A system for ablating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, the wall including at least two spaced apart zones each comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy from the source through the medium and porous material to the exterior of the wall for transmission to the return electrode to ablate
tissue located between the return electrode and the electrode, and a controller coupled to fluid source and the source of energy to control transport of electrical energy by the spaced apart zones according to preestablished criteria.
216. A system for ablating heart tissue comprising a catheter tube having a distal end for deployment in a heart chamber, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through heart tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, the wall including at least two spaced apart zones each comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy from the source through the medium and porous material to the exterior of the wall for transmission to the return electrode to ablate heart tissue located between the return electrode and the electrode, and a controller coupled to fluid source and the source of energy to control transport of
electrical energy by the spaced apart zones according to preestablished criteria.
217. A system according to claim 214 or 215 or 216 and further including at least one temperature sensing element on the wall, and wherein the controller includes means for controlling the transport of electrical energy by the spaced apart zones based at least in part upon temperature sensed by the temperature sensing element.
218. A system according to claim 217 wherein at least one the temperature sensing element is located proximal to at least one of the zones.
219. A system according to claim 217 wherein at least one temperature sensing element is located in at least one of the zones.
220. A system according to claim 217 wherein the zones of porous material have edge boundaries, and wherein the at least one temperature sensing element is located along at least one of the edge boundaries.
221. A system according to claim 214 or 215 or 216 wherein the controller includes means for specifying an electrical resistivity for the zones based, at least in part, upon a desired physiological effect.
222. A system according to claim 215 or 216 wherein the controller includes means for specifying a first electrical resistivity for the zones to achieve a first tissue lesion
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characteristic and specifying a second electrical resistivity for the zones different than the first electrical resistivity to achieve a second tissue lesion characteristic different than the first lesion characteristic.
223. A system according to claim 215 or 216 wherein the controller includes means for specifying a first electrical resistivity for the zones to achieve a deep tissue lesion geometry and specifying a second electrical resistivity for the zones greater than the first electrical resistivity to achieve a shallow tissue lesion geometry.
224. A system according to claim 214 or 215 or 216 and further including a radiopaque material carried by the electrode.
225. A system according to claim 214 or 215 or 216 wherein the porous material is hydrophilic.
226. A system according to claim 225 wherein the medium occupies the interior area subject to interior pressure, wherein the porous material has a bubble point pressure value, and wherein the bubble point pressure value exceeds the interior pressure.
227. A system according to claim 214 or 215 or 216 wherein the porous material is hydrophobic.
228. A system according to claim 227 wherein the medium occupies the interior
area subject to interior pressure, wherein the porous material has a bubble point pressure value, and wherein the bubble point pressure value is equal to or less than the interior pressure.
229. A system according to claim 214 or 215 or 216 wherein the medium occupies the interior area subject to interior pressure, wherein the porous material has a bubble point pressure value, and wherein the bubble point pressure value exceeds the interior pressure.
230. A system according to claim 214 or 215 or 216 wherein the medium occupies the interior area subject to interior pressure, wherein the porous material has a bubble point pressure value, and wherein the bubble point pressure value is equal to or less than the interior pressure.
231. A system according to claim 214 or 215 or 216 wherein the porous material includes a hydrophilic coating.
232. A system according to claim 214 or 215 or 216 wherein the wall is hydrophobic, and wherein the porous material includes a hydrophilic coating.
233. A system for ablating body tissue comprising a porous electrode comprising a wall having an interior area, an electrically conductive element in the interior area, at least
a portion of the wall comprising a porous material sized to block passage of blood cells while passing ions, an electrically conducting element to couple the electrically conductive element to a source of electrical energy, a fluid conducting element to convey a fluid medium containing ions into the interior area to enable ionic transfer of electrical energy from the electrical conducting element through the fluid medium and porous material to ablate tissue, and means for specifying differing electrical resistivities for the porous material to achieve differing desired tissue ablation effects.
234. A system for ablating body tissue to form lesions comprising a porous electrode comprising a wall having an interior area, an electrically conductive element in the interior area, at least a portion of the wall comprising a porous material sized to block passage of blood cells while passing ions, an electrically conducting element to couple the electrically conductive element to a source of electrical energy, a fluid conducting element to convey a fluid medium containing ions into the interior area to enable ionic transfer of electrical energy from the electrical conducting element through the fluid medium and porous material to ablate tissue, and means for specifying a first electrical resistivity for the porous material to achieve a first tissue lesion characteristic and specifying
a second electrical resistivity for the porous material different than the first electrical resistivity to achieve a second tissue lesion characteristic different than the first lesion characteristic.
235. A system for ablating heart tissue to form lesions comprising a porous electrode comprising a wall having an interior area, an electrically conductive element in the interior area, at least a portion of the wall comprising a porous material sized to block passage of blood cells while passing ions, an electrically conducting element to couple the electrically conductive element to a source of electrical energy, a fluid conducting element to convey a fluid medium containing ions into the interior area to enable ionic transfer of electrical energy from the electrical conducting element through the fluid medium and porous material to ablate tissue, and means for specifying a first electrical resistivity for the porous material to achieve a deep tissue lesion geometry and specifying a second electrical resistivity for the porous material greater than the first electrical resistivity to achieve a shallow tissue lesion geometry.
236. A system according to claim 233 or 234 or 235 and further including a temperature sensing element carried by the porous electrode, and further including means for specifying delivery of electrical energy to the
medium based, at least in part, upon temperature sensed by the temperature sensing element.
237. A system according to claim 233 or 234 or 235 wherein the porous material comprises a microporous membrane.
238. A system according to claim 233 or 234 or 235 wherein the porous material comprises an ultrafiltration membrane.
239. A system according to claim 233 or 234 or 235 wherein the wall includes a distal region and a proximal region, and wherein the porous material occupies more of the distal region of the wall than the proximal region.
240. A system according to claim 239 wherein at least l/3rd of the proximal region of the wall is free of pores.
241. A system according to claim 233 or 234 or 235 wherein the porous portion of the wall comprises at least first and second porous zones spaced apart by a third zone free of pores.
242. A system according to claim 241 wherein the electrode includes an axis, and wherein the first and second porous zones are circumferentially spaced apart by the third zone about the axis.
243. A system according to claim 241 wherein the electrode includes an axis, and wherein the first and second porous zones
are spaced apart by the third zone along the axis.
244. A system according to claim 233 or 234 or 235 wherein the wall is electrically conductive.
245. A system according to claim 233 or 234 or 235 and further including a radiopaque element carried by the electrode.
246. A system according to claim 233 or 234 or 235 wherein the medium carries a radiopaque contrast substance.
247. A system according to claim 233 or 234 or 235 wherein the porous portion has a porosity providing an electrical resistivity of at least about 500 ohm*cm.
248. A system according to claim 233 or 234 or 235 wherein the porous portion has a porosity providing an electrical resistivity less than about 500 ohm*cm.
249. A system according to claim 233 or 234 or 235 wherein the medium comprises a hypertonic solution.
250. A system according to claim 249 wherein the hypertonic solution includes sodium chloride.
251. A system according to claim 250 wherein the sodium chloride is present in a concentration at or near saturation.
252. A system according to claim 250 wherein the sodium chloride is present in
a concentration of up to about 9% weight by volume.
253. A system according to claim 249 wherein the hypertonic solution includes potassium chloride.
254. A system according to claim 233 or 234 or 235 wherein the medium has a resistivity lower than about 150 ohm*cm.
255. A system according to claim 254 wherein the medium has a resistivity lower than about 10 ohm*cm.
256. A system according to claim 254 wherein the medium has a resistivity lower than about 5 ohm*cm.
257. A system according to claim 233 or 234 or 235 wherein the medium includes a material whose presence increases viscosity of the medium.
258. A system according to claim 233 or 234 or 235 wherein the medium includes at least one ionic material whose presence increases viscosity of the medium.
259. A system according to claim 258 wherein the at least one ionic material comprises a radiopaque substance.
260. A system according to claim 233 or 234 or 235 wherein the medium includes a nonionic material whose presence increases viscosity of the medium.
261. A system according to claim 260 wherein the nonionic material includes glycerol.
262. A system according to claim 260 wherein the nonionic material includes mannitol.
263. A system according to claim 233 or 234 or 235 and further including means for specifying ionic transport through the porous material at a desired rate based, at least in part, upon a desired physiological effect upon tissue.
264. A system according to claim 233 or 234 or 235 wherein the porous material comprises an ultrafiltration membrane.
265. A system according to claim 233 or 234 or 235 wherein the porous section comprises a microporous membrane.
266. A system according to claim 233 or 234 or 235 and further including means for specifying constituting the medium to have a desired viscosity based, at least in part, upon a desired physiological effect upon tissue.
267. A porous electrode assembly comprising a wall surrounding an interior area, a lumen capable of conveying a medium into the interior area, the interior area capable of holding a medium containing ions, an element coupling the medium within the interior area to a source of electrical energy, at least a portion of the wall comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of
electrical energy from the source through the medium and porous material to the exterior of the wall, and at least one temperature sensing element carried by the wall in thermal contact with the exterior of the wall.
268. A porous electrode assembly comprising a wall surrounding an interior area the interior area capable of holding a medium contianing ions, an element capable of coupling the medium to a source of electrical energy, at least a portion of the wall comprising a porous material sized to pass ions contained in the medium to thereby enable ionic transport of electrical energy from the source through the medium and porous material to the exterior of the wall, and at least one temperature sensing element carried by the wall in thermal contact with the exterior of the wall.
269. A porous electrode assembly comprising a wall surrounding an interior area, a generator of radio frequency energy, a fluid source holding a medium containing ions, a lumen communicating with the interior area and the fluid source to convey into the interior area the medium containing ions, an element coupled to the generator to establish electrical contact between the medium within the interior area and the generator, at least a portion of the wall comprising
a porous material sized to pass ions contained in the medium to thereby enable ionic transport of radio frequency energy from the generator through the medium and porous material to the exterior of the wall, and at least one temperature sensing element carried by the wall in thermal contact with the exterior of the wall.
270. A porous electrode assembly according to claim 267 or 268 or 269 wherein the porous material comprises an ultrafiltration membrane.
271. A porous electrode assembly according to claim 267 or 268 or 269 wherein the porous material comprises a microporous membrane.
272. A porous electrode assembly according to claim 267 or 268 or 269 wherein the element comprises an electrically conductive electrode in the interior area of the wall.
273. An assembly according to claim 272 wherein the electrically conductive electrode comprises a nobel metal.
274. An assembly according to claim 272 wherein the electrically conductive
__electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
275. An assembly according to claim 267 or 268 or 269 wherein the medium comprises a hypertonic solution.
276. An assembly according to claim 275 wherein the hypertonic solution includes
sodium chloride.
277. An assembly according to claim 276 a concentration at or near saturation.
278. An assembly according to claim 276 wherein the sodium chloride is present in a concentration of up to about 9% weight by volume.
279. An assembly according to claim 275 wherein the hypertonic solution includes potassium chloride.
280. An assembly according to claim 267 or 268 or 269 wherein the medium has a resistivity lower than about 150 ohm*cm.
281. An assembly according to claim 267 or 268 or 269 wherein the medium has a resistivity lower than about 10 ohm*cm.
282. An assembly according to claim 267 or 268 or 269 wherein the medium has a resistivity of about 5 ohm*cm.
283. An assembly according to claim 267 or 268 or 269 wherein the medium includes a material whose presence increases viscosity of the medium.
284. An assembly according to claim 267 or 268 or 269 wherein the medium includes at least one ionic material whose presence increases viscosity of the medium.
285. An assembly according to claim 284 wherein the at least one ionic material comprises a radiopaque substance.
286. An assembly according to claim 267
or 268 or 269 wherein the medium includes a nonionic material whose presence increases viscosity of the medium.
287. An assembly according to claim 286 wherein the nonionic material includes glycerol.
288. An assembly according to claim 286 wherein the nonionic material includes mannitol.
289. An assembly according to claim 267 or 268 or 269 wherein the porous material has an electrical resistivity greater than about 500 ohm•cm.
290. An assembly according to claim 267 or 268 or 269 wherein the porous material has an electrical resistivity less than about 500 ohm*cm.
291. An assembly according to claim 267 or 268 or 269 wherein at least a portion of the wall includes an electrically conductive material.
292. An assembly according to claim 291 wherein the electrically conductive material of the wall is porous.
293. An assembly according to claim 291 wherein the electrically conductive material of the wall is nonporous.
294. An assembly according to claim 291 wherein the electrically conductive material comprises a coating deposited on the wall.
295. An assembly according to claim 291 wherein the electrically conductive
material comprises foil affixed to the wall.
296. An assembly according to claim 291 wherein the electrically conductive material is a coextruded part of the wall.
297. An assembly according to claim 291 wherein the electrically conductive material comprises noninsulated signal wire exposed on the exterior of the wall.
298. An electrode assembly according to claim 291 wherein at least a portion the wall is free of electrically conductive material.
299. An electrode assembly according to claim 267 or 268 or 269 wherein at least a portion the wall is free of electrically conductive material.
300. An assembly according to claim 267 or 268 or 269 and further including members assembled within the interior area to form a support structure underlying the wall.
301. An assembly according to claim 300 wherein the solid support members are made from metal material.
302. An assembly according to claim 301 wherein the metal material includes nickel titanium.
303. An assembly according to claim 301 wherein the metal material includes stainless steel.
304. An assembly according to claim 300 wherein the solid support members are made from plastic material.
305. An assembly according to claim 300 wherein the solid support members
comprise elongated spline elements assembled in a circumferentially spaced relationship.
306. An assembly according to claim 300 wherein the solid support members comprise a porous foam structure.
307. An assembly according to claim 267 or 268 or 269 wherein the wall includes a distal region and a proximal region, and of the distal region than the proximal region.
308. An assembly according to claim 307 wherein at least l/3rd of the proximal region is free of porous material.
309. An assembly according to claim 307 wherein the porous material occupies at least l/3rd of the distal region.
310. A system for heating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, at least a portion of the wall
comprising a porous material sized to pass ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to heat tissue located between the return electrode and the electrode, and at least one temperature sensing element carried by the wall in thermal conductive contact with the exterior of the wall.
311. A system for ablating body tissue comprising a catheter tube having a distal end, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, at least a portion of the wall comprising a porous material sized to pass ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to ablate tissue located
between the return electrode and the electrode, and at least one temperature sensing element carried by the wall in thermal conductive contact with the exterior of the wall.
312. A system for ablating heart tissue comprising a catheter tube having a distal end for deployment in a heart chamber, a return electrode, a fluid source of a medium containing ions, an electrode on the distal end of the catheter tube electrically coupled to the return electrode through heart tissue, the electrode comprising a wall having an exterior peripherally surrounding an interior area, a lumen to convey the medium containing ions from the fluid source into the interior area, an electrically conductive element in the interior area, means for coupling the electrically conductive element to a source of energy to transmit the energy, at least a portion of the wall comprising a porous material sized to pass ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium to the exterior of the wall for transmission to the return electrode to ablate heart tissue located between the return electrode and the electrode, and at least one temperature sensing element carried by the wall in thermal conductive contact with the exterior of the wall.
313. A system according to claim 310 or 311 or 312 wherein the medium comprises a hypertonic solution.
314. A system according to claim 313 wherein the hypertonic solution includes sodium chloride.
315. A system according to claim 314 wherein the sodium chloride is present in a concentration at or near saturation.
316. A system according to claim 314 wherein the sodium chloride is present in a concentration of up to about 9% weight by volume.
317. A system according to claim 310 or 311 or 312 wherein the hypertonic solution includes potassium chloride.
318. A system according to claim 317 wherein the medium has a resistivity lower than about 150 ohm*cm.
319. A system according to claim 317 wherein the medium has a resistivity lower than about 10 ohm*cm.
320. A system according to claim 317 wherein the medium has a resistivity of about 5 ohm*cm.
321. A system according to claim 310 or 311 or 312 wherein the medium includes a material whose presence increases viscosity of the medium.
322. A system according to claim 310 or 311 or 312 wherein the medium includes at least one ionic material whose presence increases viscosity
of the medium.
323. A system according to claim 322 wherein the at least one ionic material comprises a radiopaque substance.
324. A system according to claim 310 or 311 or 312 wherein the medium includes a nonionic material whose presence increases viscosity of the medium.
325. A system according to claim 324 wherein the nonionic material includes glycerol.
326. A system according to claim 324 wherein the nonionic material includes mannitol.
327. A system according to claim 310 or 311 or 312 wherein the porous material comprises an ultrafiltration membrane.
328. A system according to claim 310 or 311 or 312 wherein the porous material comprises a microporous membrane.
329. A system according to claim 310 or 311 or 312 wherein the porous material has a porosity providing an electrical resistivity greater than about 500 ohm*cm.
330. A system according to claim 310 or 311 or 312 wherein the porous material has a porosity providing an electrical resistivity less than about 500 ohm*cm.
331. A system according to claim 310 or 311 or 312
wherein at least a portion of the wall includes an electrically conductive material.
332. A system according to claim 331 wherein the electrically conductive material of the wall is porous.
333. A system according to claim 331 wherein the electrically conductive material of the wall is nonporous.
334. An electrode assembly according to claim 331 wherein at least a portion the wall is free of electrically conductive material.
335. An electrode assembly according to claim 310 or 311 or 312 free of electrically conductive material, or 311 or 312 wherein the wall includes a distal region and a proximal region, and wherein the porous material occupies more of the distal region than the proximal region.
337. An assembly according to claim 336 wherein at least l/3rd of the proximal region is free of porous material.
338. An assembly according to claim 336 wherein the porous material occupies at least l/3rd of the distal region.
339. An electrode assembly comprising a wall surrounding an interior area, at least a portion of the wall comprising an electrically conductive material, a lumen capable of conveying a medium into the interior area, the interior area capable of holding a medium containing ions, and at least a portion of the wall also comprising a porous material sized to pass ions
contained in the medium.
340. An assembly according to claim 339 wherein the porous material is adjacent to the electrically conductive material.
341. An assembly according to claim 339 or 340 and further including an element coupling the electrically conductive material to a source of electrical energy to transmit electrical energy.
342. An assembly according to claim 341 wherein the electrically conductive material is also porous to pass ions contained in the medium.
343. An assembly according to claim 341 and further including a conductive element coupling the medium within the interior area to a source of electrical energy to enable ionic transport of electrical energy by the medium through the porous material.
344. An assembly according to claim 343 wherein the conductive element comprises an electrically conductive electrode in the interior area of the wall.
345. An assembly according to claim 344 wherein the electrically conductive electrode comprises a nobel metal.
346. An assembly according to claim 345 wherein the electrically conductive electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
347. An assembly according to claim 343 wherein the electrically conductive material is also porous to pass ions contained in
the medium.
348. An assembly according to claim 339 or 340 and further including an element coupled to the electrically conductive material to convey electrical signals sensed by the electrically conductive material.
349. An assembly according to claim 348 and further including an element coupling the electrically conductive material to a source of electrical energy to transmit electrical energy.
350. An assembly according to claim 349 wherein the electrically conductive material is also porous to pass ions contained in the medium.
351. An assembly according to claim 349 and further including a conductive element coupling the medium within the interior area to a source of electrical energy to enable ionic transport of electrical energy by the medium through the porous material.
352. An assembly according to claim 351 wherein the conductive element comprises an electrically conductive electrode in the interior area of the wall.
353. An assembly according to claim 352 wherein the electrically conductive electrode comprises a nobel metal.
354. An assembly according to claim 353 wherein the electrically conductive electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
355. An assembly according to claim 353
wherein the electrically conductive material is also porous to pass ions contained in the medium.
356. An electrode assembly comprising a wall surrounding an interior area, at least a portion of the wall comprising an electrically conductive material, a lumen capable of conveying a medium into the interior area, the interior area capable of holding a medium containing ions, a conductive element capable of coupling the medium within the interior area to a source of electrical energy to enable ionic transport of electrical energy by the medium, and at least a portion of the wall also comprising a porous material sized to pass ions contained in the medium to enable ionic transport of electrical energy by the medium through the porous material to the exterior of the wall.
357. An assembly according to claim 356 wherein the porous material is adjacent to the electrically conductive material.
358. An assembly according to claim 356 or 357 and further including an element coupling the electrically conductive material to a source of electrical energy to transmit electrical energy.
359. An assembly according to claim 358 wherein the electrically conductive material is also porous to pass ions contained in the medium.
360. An assembly according to claim 356 or 357 and further including an element coupled
to the electrically conductive material to convey electrical signals sensed by the electrically conductive material.
361. An assembly according to claim 360 and further including an element coupling the electrically conductive material to a source of electrical energy to transmit electrical energy.
362. An assembly according to claim 361 wherein the electrically conductive material is also porous to pass ions contained in the medium.
363. An assembly according to claim 356 or 357 wherein the conductive element comprises an electrically conductive electrode in the interior area of the wall.
364. An assembly according to claim 363 wherein the electrically conductive electrode comprises a nobel metal.
365. An assembly according to claim 363 wherein the electrically conductive electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
366. An assembly according to claim 356 or 357 wherein the porous material is sized to block passage of macromolecules.
367. An assembly according to claim 356 or 357 wherein the porous material comprises an ultrafiltration membrane.
368. An assembly according to claim 356 or 357
wherein the porous material comprises a microporous membrane.
369. An assembly according to claim 339 or 356 wherein the electrically conductive material comprises a coating deposited on the wall.
370. An assembly according to claim 339 or 356 wherein the electrically conductive material comprises foil affixed to the wall.
371. An assembly according to claim 339 or 356 wherein the electrically conductive material is a coextruded part of the wall.
372. An assembly according to claim 339 or 356 wherein the electrically conductive material comprises noninsulated signal wire exposed on the exterior of the wall.
373. An assembly according to claim 339 or 356 wherein the medium comprises a hypertonic solution.
374. An assembly according to claim 373 wherein the hypertonic solution includes sodium chloride.
375. An assembly according to claim 374 wherein the sodium chloride is present in a concentration at or near saturation.
376. An assembly according to claim 374 wherein the sodium chloride is present in a concentration of up to about 9% weight by volume.
377. An assembly according to claim 373
wherein the hypertonic solution includes potassium chloride.
378. An assembly according to claim 339 or 356 wherein the medium has a resistivity lower than about 150 ohm*cm.
379. An assembly according to claim 339 or 356 wherein the medium has a resistivity lower than about 10 ohm*cm.
380. An assembly according to claim 339 or 356 wherein the medium has a resistivity of about 5 ohm*cm.
381. An assembly according to claim 339 or 356 wherein the medium includes a material whose presence increases viscosity of the medium.
382. An assembly according to claim 339 or 356 wherein the medium includes at least one ionic material whose presence increases viscosity of the medium.
383. An assembly according to claim 382 wherein the at least one ionic material comprises a radiopaque substance.
384. An assembly according to claim 339 or 356 wherein the medium includes a nonionic material whose presence increases viscosity of the medium.
385. An assembly according to claim 384 wherein the nonionic material includes glycerol.
386. An assembly according to claim 384
wherein the nonionic material includes mannitol.
387. An assembly according to claim 339 or 356 wherein the porous material has an electrical resistivity greater than about 500 ohm•cm.
388. An assembly according to claim 339 or 356 wherein the porous material has an electrical resistivity less than about 500 ohm*cm.
389. An assembly according to claim 339 or 356 and further including members assembled within the interior area to form a support structure underlying the wall.
390. An assembly according to claim 389 wherein the solid support members are made from metal material.
391. An assembly according to claim 390 wherein the metal material includes nickel titanium.
392. An assembly according to claim 390 wherein the metal material includes stainless steel.
393. An assembly according to claim 390 wherein the solid support members are made from plastic material.
394. An assembly according to claim 390 wherein the solid support members comprise elongated spline elements assembled in a circumferentially spaced relationship.
395. An assembly according to claim 390 wherein the solid support members comprise a porous foam structure.
396. An assembly according to claim 339 or 356 wherein the porous material is hydrophilic.
397. An assembly according to claim 339 or 356 wherein the lumens conveys a medium containing ions into the interior area subject to an interior pressure, and wherein the porous material has a bubble point value greater than the interior pressure.
398. An assembly according to claim 397 wherein the porous material is hydrophilic.
399. A system for heating body tissue comprising a source of a medium containing ions, a generator of electrical energy, an electrode comprising a wall having an exterior peripherally surrounding an interior area, at least a portion of the wall comprising an electrically conductive material having a surface area for transmitting electrical energy, a lumen to convey medium containing ions from the source into the interior area of the wall, at least a portion of the wall adjacent to the electrically conductive material comprising a porous material sized to pass ions contained in the medium, and a controller coupled to the source and to the generator to achieve a desired tissue heating effect by commanding conveyance of electrical energy by the generator for transmission by the electrically conductive material while commanding conveyance of medium containing ions by the source, thereby enabling ionic transport through
the porous material while the electrically conductive material transmits electrical energy to create an effective surface area of electrical energy transmission that is greater than the surface area of the electrically conductive material.
400. A system according to claim 399 and further including a conductive element coupling the medium within the interior area of the wall to the generator, and wherein the controller is coupled to the conductive element to command conveyance of electrical energy by the generator to the element to enable ionic transport of electrical energy by the medium through the porous material while the electrically conductive material transmits electrical energy.
401. A system for heating body tissue comprising a source of a medium containing ions, a generator of electrical energy, an electrode comprising a wall surrounding an interior area, at least a portion of the wall comprising an electrically conductive material having a surface area for transmitting electrical energy, a lumen capable of conveying medium containing ions from the source into the interior area, at least a portion of the wall adjacent to the electrically conductive material comprising a porous material sized to pass ions contained in the medium, a conductive element capable of coupling the medium within the interior area of the wall to the generator, and a controller coupled to the source, the
generator, and the element to achieve a desired tissue heating effect by commanding conveyance of electrical energy by the generator to the element and the electrically conductive material while commanding conveyance of medium containing ions by the source into the interior area to enable ionic transport of electrical energy through the porous material while the electrically conductive material transmits electrical energy to create an effective surface area of electrical energy transmission that is greater than the surface area of the electrically conductive material.
402. A system according to claim 399 or 400 or 401 wherein the controller is operative for achieving the desired tissue heating effect by ablating body tissue.
403. A system according to claim 399 or 400 or 401 wherein the controller is operative for achieving the desired tissue heating effect by ablating heart tissue.
404. A system for ablating heart tissue comprising a source of a medium containing ions, a generator of electrical energy, a processor for processing electrical events sensed in heart tissue, an electrode comprising a wall having an exterior peripherally surrounding an interior area, at least a portion of the wall comprising an electrically conductive material having a surface area for sensing electrical events in heart tissue and transmitting electrical energy, a lumen to convey medium containing ions from the source into
the interior area of the wall, at least a portion 5 of the wall adjacent to the electrically conductive material comprising a porous material sized to pass ions contained in the medium, and a controller coupled to the source, to the generator, and to the processor, the 0 controller operative in a first mode commanding the electrically conductive material to sense electrical events in heart tissue for conveyance to the processor, the controller being operative in a second mode commanding conveyance of 5 electrical energy by the generator for transmission by the electrically conductive material while commanding conveyance of medium containing ions, thereby enabling ionic transport through the porous material while the electrically 0 conductive material transmits electrical energy to create an effective surface area of electrical energy transmission for ablating heart tissue that is greater than the surface area of the electrically conductive material.
405. A system according to claim 404 and further including a conductive
_ element coupling the medium within the interior area of the wall to the generator, and
5 wherein the controller is coupled to the element to command, during the second mode, conveyance of electrical energy by the generator to the element to enable ionic transport of electrical energy by the medium through the porous 0 material while the electrically conductive material transmits electrical energy.
406. A system for ablating heart tissue comprising a source of a medium containing ions,
a generator of electrical energy, a processor for processing electrical events sensed in heart tissue, an electrode comprising a wall having an exterior peripherally surrounding an interior area, at least a portion of the wall comprising an electrically conductive material having a surface area for sensing electrical events in heart tissue and transmitting electrical energy, a lumen to convey medium containing ions from the source into the interior area of the wall, at least a portion of the wall adjacent to the electrically conductive material comprising a porous material sized to pass ions contained in the medium, a conductive element coupling the medium within the interior area of the wall to the generator, and a controller coupled to the source, to the generator, and to the processor, the controller operative in a first mode commanding the electrically conductive material to sense electrical events in heart tissue for conveyance to the processor, the controller being operative in a second mode commanding conveyance of electrical energy by the generator for transmission by the electrically conductive material while commanding conveyance of medium containing ions by the source into the interior area to enable ionic transport of electrical energy through the porous material while the electrically conductive material transmits electrical energy to create an effective surface area of electrical energy transmission for ablating heart tissue that is greater than the surface area of the electrically conductive
material.
407. A system according to claim 404 or 405 or 406 wherein the porous material is sized to block passage of macromolecules.
408. A system according to claim 401 or 406 wherein the porous material comprises an ultrafiltration membrane.
409. A system according to claim 401 or 406 wherein the porous material comprises a microporous membrane.
410. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the conductive element comprises an electrically conductive electrode in the interior area of the wall.
411. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the electrically conductive material comprises a coating deposited on the wall.
412. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the electrically conductive material comprises foil affixed to the wall.
413. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the electrically conductive material is a coextruded part of the wall.
414. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the electrically conductive material comprises noninsulated signal wire
exposed on the exterior of the wall.
415. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the medium comprises a hypertonic solution.
416. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the medium has a resistivity lower than about 150 ohm*cm.
417. A system according to claim 416 wherein the medium has a resistivity lower than about 10 ohm*cm.
418. A system according to claim 416 wherein the medium has a resistivity of about 5 ohm*cm.
419. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the porous material has an electrical resistivity greater than about 500 ohm*cm.
420. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the porous material has an electrical resistivity less than about 500 ohm*cm.
421. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the porous material is hydrophilic.
422. A system according to claim 400 or 401 or 402 or 405 or 406 wherein the lumens conveys a medium containing ions into the interior area subject to an interior pressure, and wherein the porous material has a bubble point value greater than the interior pressure.
423. A system according to claim 422 wherein the porous material is hydrophilic.
424. An electrode assembly comprising a wall surrounding an interior area, at least a portion of the wall comprising an electrically conductive material capable of being coupled to a source of electrical energy to transmit electrical energy, a lumen capable of convey a medium into the interior area, the interior area capable of holding a medium containing ions, and at least a portion of the electrically conductive material comprising a porous material sized to pass ions contained in the medium.
425. An assembly according to claim 424 and further including a conductive element coupling the medium within the interior area to a source of electrical energy to enable ionic transport of electrical energy by the medium through the porous material.
426. An assembly according to claim 425 wherein the conductive element comprises an electrically conductive electrode in the interior area of the wall.
427. An assembly according to claim 426 wherein the electrically conductive electrode comprises a nobel metal.
428. An assembly according to claim 426 wherein the electrically conductive electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
429. An assembly according to claim 424 or 425
and further including an element coupled to the electrically conductive material to convey electrical signals sensed by the electrically conductive material.
430. An electrode assembly comprising a wall surrounding an interior area, at least a portion of the wall comprising an electrically conductive material coupled to a source of electrical energy to transmit electrical energy, a lumen capable of conveying a medium into the interior area, the interior area capable of holding a medium containing ions, and at least a portion of the electrically conductive material comprising a porous material sized to pass ions contained in the medium, and a conductive element capable of coupling the medium within the interior area to a source of electrical energy to enable ionic transport of electrical energy by the medium through the porous material.
431. An assembly according to claim 430 and further including an element coupled to the electrically conductive material to convey electrical signals sensed by the electrically conductive material.
432. An assembly according to claim 430 wherein the conductive element comprises an electrically conductive electrode in the interior area of the wall.
433. An assembly according to claim 432 wherein the electrically conductive electrode comprises a nobel metal.
434. An assembly according to claim 432 wherein the electrically conductive
electrode includes a material selected from the group consisting essentially of gold, platinum, platinum/iridium, or combinations thereof.
435. An assembly according to claim 430 wherein the porous material is sized to block passage of macromolecules.
436. An assembly according to claim 430 wherein the porous material comprises an ultrafiltration membrane.
437. An assembly according to claim 430 wherein the porous material comprises a microporous membrane.
438 An assembly according to claim 423 or 430 wherein the medium comprises a hypertonic solution.
439. An assembly according to claim 423 wherein the hypertonic solution includes sodium chloride.
440. An assembly according to claim 439 wherein the sodium chloride is present in a concentration at or near saturation.
441. An assembly according to claim 439 wherein the sodium chloride is present in a concentration of up to about 9% weight by volume.
442. An assembly according to claim 436 wherein the hypertonic solution includes potassium chloride.
443. An assembly according to claim 1 or 430 wherein the medium has a resistivity lower than about 150 ohm*cm.
444. An assembly according to claim 422 or 430
wherein the medium has a resistivity lower than about 10 ohm*cm.
445 An assembly according to claim 422 or 430 wherein the medium has a resistivity of about 5 ohm*cm.
446. An assembly according to claim 422 or 430 wherein the medium includes a material whose presence increases viscosity of the medium.
447. An assembly according to claim 422 or 430 wherein the medium includes at least one ionic material whose presence increases viscosity of the medium.
448. An assembly according to claim 447 wherein the at least one ionic material comprises a radiopaque substance.
449. An assembly according to claim 422 or 430 wherein the medium includes a nonionic material whose presence increases viscosity of the medium.
450. An assembly according to claim 449 wherein the nonionic material includes glycerol.
451 An assembly according to claim 448 wherein the nonionic material includes mannitol.
452. An assembly according to claim 422 or 430 wherein the porous material has an electrical resistivity greater than about 500 ohm•cm.
453. An assembly according to claim 422
or 430 wherein the porous material has an electrical resistivity less than about 500 ohm*cm.
454. An assembly according to claim 422 or 430 and further including members assembled within the interior area to form a support structure underlying the wall.
455. An assembly according to claim 454 wherein the solid support members are made from metal material.
456. An assembly according to claim 454 wherein the metal material includes nickel titanium.
457. An assembly according to claim 454 wherein the metal material includes stainless steel.
458 An assembly according to claim 454 wherein the solid support members are made from plastic material.
459. An assembly according to claim 454 wherein the solid support members comprise elongated spline elements assembled in a circumferentially spaced relationship.
460. An assembly according to claim 454 wherein the solid support members comprise a porous foam structure.
461. An assembly according to claim 422 or 430 wherein the porous material is hydrophilic.
462. An assembly according to claim 422 or 430 wherein the lumens conveys a medium containing ions into the interior area subject to
an interior pressure, and the porous material has a bubble point value greater than the interior pressure.
463. An assembly according to claim wherein the porous material is hydrophilic.
464. A system for heating body tissue comprising a source of a medium containing ions, a generator of electrical energy, an electrode comprising a wall having an exterior peripherally surrounding an interior area, at least a portion of the wall comprising an electrically conductive material coupled to a source of electrical energy to transmit electrical energy, a lumen to convey a medium containing ions into the interior area, and at least a portion of the electrically conductive material comprising a porous material sized to pass ions contained in the medium, and a controller coupled to the source and to the generator to achieve a desired tissue heating effect by commanding conveyance of electrical energy by the generator for transmission by the electrically conductive material while commanding conveyance of medium containing ions by the source, thereby enabling ionic transport through the porous material while the electrically conductive material transmits electrical energy.
465. A system according to claim 464 and further including a conductive element coupling the medium within the interior area of the wall to the generator, and wherein the controller is coupled to the conductive element to command conveyance of
electrical energy by the generator to the element to enable ionic transport of electrical energy by the medium through the porous material while the electrically conductive material transmits electrical energy.
466. A system for heating body tissue comprising a source of a medium containing ions, a generator of electrical energy, an electrode comprising a wall having an exterior peripherally surrounding an interior area, at least a portion of the wall comprising an electrically conductive material coupled to a source of electrical energy to transmit electrical energy, a lumen to convey a medium containing ions into the interior area, at least a portion of the electrically conductive material comprising a porous material sized to pass ions contained in the medium, a conductive element coupling the medium within the interior area of the wall to the generator, and a controller coupled to the source, the generator, and the conductive element to achieve a desired tissue heating effect by commanding conveyance of electrical energy by the generator to the conductive element and the electrically conductive material while commanding conveyance of medium containing ions by the source into the interior area to enable ionic transport of electrical energy through the porous material while the electrically conductive material transmits electrical energy.
467. A system according to claim 464 or 465 or 466
wherein the controller is operative for achieving the desired tissue heating effect by ablating body tissue.
468. A system according to claim 464 or 465 or 466 wherein the controller is operative for achieving the desired tissue heating effect by ablating heart tissue.
469. A system for ablating heart tissue comprising a source of a medium containing ions, a generator of electrical energy, a processor for processing electrical events sensed in heart tissue, an electrode comprising a wall having an exterior peripherally surrounding an interior area, at least a portion of the wall comprising an electrically conductive material coupled to a source of electrical energy to transmit electrical energy, a lumen to convey a medium containing ions into the interior area, and at least a portion of the electrically conductive material comprising a porous material sized to pass ions contained in the medium, and a controller coupled to the source, to the generator, and to the processor, the controller operative in a first mode commanding the electrically conductive material to sense electrical events in heart tissue for conveyance to the processor, the controller being operative in a second mode commanding conveyance of electrical energy by the generator for transmission by the electrically conductive material while commanding conveyance of medium containing ions, thereby enabling ionic transport
through the porous material while the electrically conductive material transmits electrical energy.
470. A system according to claim 469 and further including a conductive element coupling the medium within the interior area of the wall to the generator, and wherein the controller is coupled to the element to command, during the second mode, conveyance of electrical energy by the generator to the element to enable ionic transport of electrical energy by the medium through the porous material while the electrically conductive material transmits electrical energy.
471. A system for ablating heart tissue comprising a source of a medium containing ions, a generator of electrical energy, a processor for processing electrical events sensed in heart tissue, an electrode comprising a wall having an exterior peripherally surrounding an interior area, at least a portion of the wall comprising an electrically conductive material coupled to a source of electrical energy to transmit electrical energy, a lumen to convey a medium containing ions into the interior area, at least a portion of the electrically conductive material comprising a porous material sized to pass ions contained in the medium, a conductive element coupling the medium within the interior area of the wall to the generator, and a controller coupled to the source, to the generator, and to the processor, the controller operative in a first mode commanding
the electrically conductive material to sense electrical events in heart tissue for conveyance to the processor, the controller being operative in a second mode commanding conveyance of electrical energy by the generator for transmission by the electrically conductive material while commanding conveyance of medium containing ions by the source into the interior area to enable ionic transport of electrical energy through the porous material while the electrically conductive material transmits electrical energy.
472. A system according to claim 466 or 471 wherein the porous material is sized to block passage of macromolecules.
473. A system according to claim 466 or 471 wherein the porous material comprises an ultrafiltration membrane.
474. A system according to claim 466 or 471 wherein the porous material comprises a microporous membrane.
475. A system according to claim 468 or 469 or 470 or 471 wherein the conductive element comprises an electrically conductive electrode in the interior area of the wall.
476. A system according to claim 466 or 467 or 4683 or 469 or 470 or 471 wherein the medium comprises a hypertonic solution.
477. A system according to claim 466 or 467 or 4683 or 469 or 470 or 471
wherein the medium has a resistivity lower than about 150 ohm*cm.
478. A system according to claim 477 wherein the medium has a resistivity lower than about 10 ohm*cm.
479. A system according to claim 477 wherein the medium has a resistivity of about 5 ohm•cm.
480 A system according to claim 466 or 467 or 4683 or 469 or 470 or 471 wherein the porous material has an electrical resistivity greater than about 500 ohm•cm.
481. A system according to claim 466 or 467 or 4683 or 469 or 470 or 471 wherein the porous material has an electrical resistivity less than about 500 ohm*cm.
482. A system according to claim 466 or 467 or 4683 or 469 or 470 or 471 wherein the porous material is hydrophilic.
483. A system according to claim 466 or 467 or 4683 or 469 or 470 or 471 wherein the lumens conveys a medium containing ions into the interior area subject to an interior pressure, and wherein the porous material has a bubble point value greater than the interior pressure.
484. A system according to claim 483 wherein the porous material is hydrophilic.
485. A system for ablating body tissue comprising an electrode including an exterior wall adapted to contact tissue, the wall surrounding an
interior area, a lumen to convey a medium containing ions into the interior area, at least a portion of the wall of the electrode comprising a porous material sized to pass ions contained in the medium, and an electrically conductive element contacting the medium within the interior area, a generator of electrical ablation energy coupled to the electrically conductive element to transmit electrical ablation energy to the electrically conductive element for ionic transport through the medium and porous material to tissue, at least one sensing element carried by the exterior wall of the electrode to sense temperature, and a controller coupled to the generator and the at least one sensing element to govern transmission of electrical ablation energy to the electrically conductive element based, at least in part, upon temperature sensed by the at least one sensing element.
486. A system according to claim 485 wherein the controller specifies a targeted electrical ablation energy power level delivered to the electrically conductive element based, at least in part, upon temperature sensed by the at least one sensing element.
487. A system according to claim 485 wherein the controller specifies a duty cycle for the delivery of electrical ablation energy to the electrically conductive element.
488. A system according to claim 486 wherein the controller delivers electrical ablation energy to the electrically conductive element in power pulses.
489 A system according to claim 486 wherein the controller specifies a targeted maximum temperature condition to be sensed by the sensing element while the electrode ionically transmits ablation energy.
490. A system according to claim 489 wherein the controller periodically compares temperature sensed by the at least one sensing element to the targeted maximum temperature condition and generates a command to govern transmission of electrical ablation energy to the electrically conductive element based, at least in part, upon the comparison.
491. A system according to claim 485 or 486 wherein the controller includes an element for inputting a desired therapeutic result including at least a targeted lesion depth.
492. A system according to claim 491 wherein the controller includes processing means for specifying an operating condition based upon the desired therapeutic result including establishing a targeted maximum temperature condition to be sensed by the sensing element while the electrode ionically transmits ablation energy.
493. A system according to claim 492 wherein the controller compares temperature sensed by the at least one sensing element to the targeted maximum temperature condition and generates a command to govern transmission of electrical ablation energy to the electrically conductive element based, at least in part, upon the comparison.
494. A system according to claim 485 or
486 wherein the controller specifies a targeted electrical resistivity for the porous material of the exterior wall.
495. A system according to claim 494 wherein the targeted electrical resistivity is greater than about 500 ohm*cm.
496. A system according to claim 494 wherein the targeted electrical resistivity is less than about 500 ohm*cm.
497. A system according to claim 485 or 486 wherein the controller specifies a targeted electrical resistivity for the medium.
498. A system according to claim 497 wherein the targeted electrical resistivity for the medium is less than about 150 ohm•cm.
499. A system according to claim 497 wherein the targeted electrical resistivity for the medium is about 5 ohm*cm.
500. A system according to claim 485 or 486 wherein the controller specifies a liquid perfusion rate of medium through the porous material.
501 A system according to claim 500 wherein the controller includes means for maintaining rate of liquid perfusion below a maximum value based, at least in part, upon physiologic fluid overload considerations.
502. A system according to claim 500 wherein the controller specifies viscosity of the fluid medium to, at least in part, establish the perfusion rate.
503. A system according to claim 485 or
486 wherein the controller includes sensing means for sensing impedance proximate to where the exterior wall contacts tissue.
504. A system according to claim 503 wherein the controller specifies a liquid perfusion rate of fluid medium through the porous material to stabilize impedance sensed by the sensing means at a generally constant minimum value.
505. A system according to claim 503 wherein the controller specifies a liquid perfusion rate of fluid medium through the porous material above a value at which impedance sensed by the sensing means is below a set maximum value.
506. A system according to claim 485 or 486 wherein the electrical ablation energy comprises radio frequency energy.
507. A system according to claim 485 or 486 wherein the porous material comprises an ultrafiltration membrane.
508. A system according to claim 507 wherein the controller specifies a targeted electrical resistivity for the ultrafiltration membrane.
509. A system according to claim 508 wherein the targeted electrical resistivity is greater than about 500 ohm*cm.
510. A system according to claim 508 wherein the targeted electrical resistivity is less than about 500 ohm*cm.
511. A system according to claim 485 or
486 wherein the porous material comprises a microporous membrane.
512. A system according to claim 511 wherein the controller specifies a targeted electrical resistivity for the microporous membrane.
513. A system according to claim 512 wherein the targeted electrical resistivity is greater than about 500 ohm*cm.
514. A system according to claim 512 wherein the targeted electrical resistivity is less than about 500 ohm*cm.
515. A system according to claim 485 or 486 wherein the controller specifies an interior pressure for the interior area less than bubble point value of the porous material.
516. A system for ablating body tissue comprising an electrode including a wall adapted to contact tissue, the wall surrounding an interior area, a lumen to convey a medium containing ions into the interior area, the wall of the electrode comprising spaced apart first and second zones of porous material, each sized to pass ions contained in the medium, a generator of electrical ablation energy coupled to the medium in the interior area of the electrode to transmit electrical ablation energy for ionic transport through the medium and the first and second zones of porous material to tissue, first and second sensing elements carried by the wall proximal to, respectively, the first
and second zones of porous material to sense temperature, and a controller coupled to the generator and the first and second sensing elements to govern transmission of electrical ablation energy to the medium based, at least in part, upon temperatures sensed by the first and second sensing elements.
517. A system according to claim 516 wherein the controller specifies a targeted electrical ablation energy power level delivered to the medium based, at least in part, upon temperature sensed by at least one of the sensing elements.
518. A system according to claim 516 wherein the controller specifies a duty cycle for the ionic transport of electrical ablation energy through the first and second zones of porous material based, at least in part, upon temperatures sensed by the first and second sensing elements.
519. A system according to claim 517 wherein the controller delivers electrical ablation energy by ionic transport through the first and second zones of porous material in pulses.
520. A system according to claim 516 wherein the controller specifies a targeted maximum temperature condition to be sensed by the first and second sensing elements while the electrode ionically transmits ablation energy.
521. A system according to claim 520 wherein the controller periodically compares temperatures sensed by the first and second sensing elements to the targeted maximum
temperature condition and generates a command to govern ionic transport through the first and second porous zones based, at least in part, upon the comparison.
522. A system according to claim 520 wherein the controller includes an element for inputting a desired therapeutic result including at least a targeted lesion depth.
523. A system according to claim 522 wherein the controller includes processing means for specifying an operating condition based upon the desired therapeutic result including establishing a targeted maximum temperature condition to be sensed by the first and second sensing elements while the electrode ionically transmits ablation energy.
524. A system according to claim 523 wherein the controller periodically compares temperatures sensed by the first and second sensing elements to the targeted maximum temperature condition and generates a command to govern ionic transport through the first and second porous zones based, at least in part, upon the comparison.
525. A system according to claim 522 wherein at least one of the zones of porous material comprises an ultrafiltration membrane.
526. A system according to claim 516 wherein at least one of the zones of porous material comprises a microporous membrane.
527. A system according to claim 516 wherein the controller specifies an interior pressure for the interior area less than bubble point value of the porous material.