Defibrillation system having segmented electrodes

• US 6,148,233 A
• Filed: 03/06/1998
• Issued: 11/14/2000
• Est. Priority Date: 03/07/1997
• Status: Expired due to Term

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Cardiac Science Operating Company (Cardica Incorporated)
• Inventors: O'Leary, James P., Owen, James M., Totman, Mark H., Fincke, Randall W.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US09/036,265
• Time in Patent Office: 984 Days
• Field of Search: 607/115, 607/142, 607/148, 607/152, 607/153
• US Class Current: 607/5
• CPC Class Codes: A61N 1/0452 Specially adapted for transcutaneous muscle stimulation [TMS]
• CPC Class Codes: A61N 1/0456 Specially adapted for transcutaneous electrical nerve stimulation [TENS]
• CPC Class Codes: A61N 1/046 Specially adapted for shock therapy, e.g. defibrillation
• CPC Class Codes: A61N 1/0468 Specially adapted for promoting wound healing
• CPC Class Codes: A61N 1/0472 Structure-related aspects
• CPC Class Codes: A61N 1/0476 Array electrodes (including any electrode arrangement with more than one electrode for at least one of the polarities)
• CPC Class Codes: A61N 1/0492 Patch electrodes A61N1/0412, A61N1/0428 take precedence
• CPC Class Codes: A61N 1/0496 characterised by using specific chemical compositions, e.g. hydrogel compositions, adhesives
• CPC Class Codes: A61N 1/3904 External heart defibrillators [EHD]
• CPC Class Codes: A61N 1/3918 characterised by shock pathway, e.g. by electrode configuration
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3937 Monitoring output parameters
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock
• CPC Class Codes: A61N 1/3993 User interfaces for automatic external defibrillators

Abstract

Electrode devices optimized for long-term wear in conjunction with an external cardiac defibrillator are described. In preferred embodiments the electrode devices include electrodes that consist of multiple segments, thereby providing enhanced efficacy and impedance characteristics relative to conventionally shaped continuous electrodes. In certain embodiments the conductive surface for contacting a patient'"'"'s skin of the electrodes is continuous but contains regions separated by open spaces, thereby similarly providing enhanced efficacy and impedance characteristics. The electrode devices are fabricated using materials selected to minimize skin irritation and discomfort.

Claims

1. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient;

a skin interface; and

a nonconductive connecting element,

wherein at least one electrode comprises at least two electrode segments spatially arranged on the element, each electrode segment having a perimeter and a conductive surface for contacting a patient'"'"'s skin and for delivering electrical therapy to the patient, and wherein the electrode segments have a total combined area of the conductive surfaces for contacting a patient'"'"'s skin that is less than the area of the conductive surface for contacting a patient'"'"'s skin that would be required for a conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin, wherein the conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin has an equivalent efficacy for delivering electrical therapy to that of the at least one electrode.

2. The electrode device of claim 1, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

3. The segmented electrode device of claim 1, wherein the at least two electrode segments are spatially arranged so that the perimeters of the at least two electrode segments are separated from one another by between 0.5 times the smallest effective diameter of any of the at least two electrode segments and 3.0 times the largest effective diameter of any of the at least two electrode segments.

4. The electrode device of claim 3, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

15. The segmented electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, or 14, wherein the shape of the conductive surface for contacting a patient'"'"'s skin of at least one electrode segment is noncircular.

16. The segmented electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, or 14, wherein the nonconductive connecting element comprises an applicator assembly.

17. The electrode device of claim 16, further comprising at least one top cover assembly, and wherein the applicator assembly comprises:

a top layer and a bottom layer, each layer having an upper and a lower surface, wherein the lower surface of the bottom layer contacts the at least one top cover assembly, and wherein the top layer comprises an adhesive.

18. The electrode device of claim 17, wherein the bottom layer of the applicator assembly contains cutouts that limit the amount of contact between the adhesive of the top layer and the top cover assembly of the electrode so that the top layer of the applicator is removable from the applicator assembly without damaging the electrodes.

19. The electrode device of claim 17, wherein at least one electrode further comprises a release liner assembly comprising a top layer and a bottom layer, wherein the upper surface of the top layer contacts the skin interface.

20. The electrode device of claim 19, wherein the upper layer of the release liner assembly contains at least one cutout so that the release liner assembly is removable from the remainder of the electrode without causing separation of the electrode from the applicator assembly.

21. The electrode device of claim 17, wherein the at least one top cover assembly comprises an insulating layer.

22. The electrode device of claim 21, wherein the insulating layer comprises a foam pad.

23. The electrode device of claim 22, wherein the at least one top cover assembly further comprises an adhesive layer for use in attaching the electrode device to a patient'"'"'s skin.

24. The electrode device of claim 23, wherein the adhesive layer comprises a wearable adhesive and optionally comprises a flexible backing layer having a moisture vapor transmission rate of approximately 300 to 1500 g/m² /day.

25. The electrode device of claim 24, wherein the wearable adhesive has a moisture vapor transmission rate of approximately 300 to 1500 g/m² /day.

26. The electrode device of claim 25, wherein the wearable adhesive has a peel strength of less than approximately 500 g/cm.

46. The electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, or 44, wherein the total area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is less than 60 cm².

47. The electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, or 44, wherein the total area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is less than 50 cm².

48. The electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, or 44, wherein the total area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is less than 40 cm².

49. The electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, or 44, wherein the total area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is less than 30 cm².

50. The electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, or 44, wherein the skin interface comprises a conductive mesh.

51. The electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, or 44, wherein each electrode comprises:

a conductor/wire assembly.

52. The electrode device of claim 51, wherein the conductor/wire assembly comprises a conductive layer comprising a silver/silver chloride-containing, polymer-based ink.

53. The electrode device of claim 51, wherein the conductor/wire assembly comprises a conductive backing plate made of at least one material selected from the list consisting of conductive metals, conductive metal oxides, conductive metal salts, and silver chloride.

54. The electrode device of claim 51, wherein the conductor/wire assembly comprises a porous conductive layer.

55. The electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, or 44, wherein the skin interface comprises a conductive hydrogel.

56. The electrode device of claim 55, wherein the skin interface comprises a conductive hydrogel having an electrolyte concentration of between approximately 0.9% to 3.0% by weight.

57. The electrode device of claim 55, wherein the conductive hydrogel comprises a hydrating agent at a concentration of between about 10% to 70% by weight.

58. The electrode device of claim 55, wherein the conductive hydrogel comprises a therapeutic or prophylactic agent to minimize skin irritation or damage.

59. The electrode device of any of claims 1, 2, 5, 6, 9, 10, 3, 4, 7, 8, 11, 12, 13, 14, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, or 44, further comprising a power supply.

60. The electrode device of claim 59 further comprising:

leads for conducting current to the electrodes; and

means for connecting the leads to the power supply, whereby the leads cannot be removed from the power supply without damaging at least one of the leads or damaging the power supply.

61. The electrode device of claim 59, wherein the power supply further comprises means for rendering said power supply water-resistant.

62. The electrode device of claim 61, wherein the power supply is sealed within a membrane so as to render said power supply water-resistant.

63. The electrode device of claim 61 further comprising:

leads for conducting current to the electrodes; and

means for connecting the leads to the power supply, whereby the leads cannot be removed from the power supply without damaging at least one of the leads or damaging the power supply.

5. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient;

a skin interface; and

a nonconductive connecting element,

wherein at least one electrode comprises at least two electrode segments spatially arranged on the element, each of the at least two electrode segments having a perimeter and a conductive surface for contacting a patient'"'"'s skin for delivering electrical therapy to the patient, so that when the at least one electrode comprising at least two spatially arranged electrode segments is applied to a patient and used to deliver a therapeutically effective level of electrical therapy, the trans-thoracic impedance is less than the trans-thoracic impedance resulting when a conventional electrode applied to the same patient is used to deliver a therapeutically effective level of electrical therapy, wherein the conventional electrode has a continuous conductive surface for contacting a patient'"'"'s skin having an area equivalent to the total combined area of the conductive surfaces for contacting a patient'"'"'s skin of the at least two electrode segments.

6. The electrode device of claim 5, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

7. The segmented electrode device of claim 5, wherein the at least two electrode segments are spatially arranged so that the perimeters of the at least two electrode segments are separated from one another by between 0.5 times the smallest effective diameter of any of the at least two electrode segments and 3.0 times the largest effective diameter of any of the at least two electrode segments.

8. The electrode device of claim 7, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

9. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient;

a skin interface; and

a nonconductive connecting element,

wherein at least one electrode comprises at least two electrode segments spatially arranged on the element, each electrode segment having a perimeter and a conductive surface for contacting a patient'"'"'s skin for delivering electrical therapy to the patient, so that the effective conductive area of the at least one electrode comprising at least two electrode segments is greater than the total combined area of the conductive surfaces for contacting a patient'"'"'s skin of the electrode segments.

10. The electrode device of claim 9, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

11. The segmented electrode device of claim 9, wherein the at least two electrode segments are spatially arranged so that the perimeters of the at least two electrode segments are separated from one another by between 0.5 times the smallest effective diameter of any of the at least two electrode segments and 3.0 times the largest effective diameter of any of the at least two electrode segments.

12. The electrode device of claim 11, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

14. The electrode device of claim 11, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

13. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient;

a skin interface; and

a nonconductive connecting element,

wherein at least one electrode comprises at least two electrode segments spatially arranged on the element, each electrode segment having a perimeter and a conductive surface for contacting a patient'"'"'s skin and for delivering electrical therapy to the patient, and wherein the electrode device comprises at least one material selected to enhance the long-term wearability of the electrode device.

27. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient for delivering electrical therapy to the patient, each electrode having a conductive surface for contacting a patient'"'"'s skin, the conductive surface for contacting a patient'"'"'s skin having a shape and a perimeter; and

a skin interface,

wherein the shape of the conductive surface for contacting a patient'"'"'s skin of at least one electrode is selected so that the area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is less than the area of the conductive surface for contacting a patient'"'"'s skin that would be required for a conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin, wherein the conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin has an equivalent efficacy for delivering electrial therapy to that of the at least one electrode.

28. The electrode device of claim 27, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

40. The electrode device of any of claims 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, or 39, wherein the shape of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is selected from the group consisting of:

E shapes, F shapes, L shapes, H shapes, X shapes, C shapes, crescent shapes, and doughnuts.

42. The electrode device of any of claims 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 41 further comprising an applicator assembly.

43. The electrode device of any of claims 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 41, wherein the electrode device comprises at least one material selected to enhance long-term wearability of the electrode device.

29. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient for delivering electrical therapy to the patient, each electrode having a conductive surface for contacting a patient'"'"'s skin, the conductive surface for contacting a patient'"'"'s skin having a shape and a perimeter; and

a skin interface,

wherein the shape of the conductive surface for contacting a patient'"'"'s skin of at least one electrode is selected so that the effective conductive area of the at least one electrode is greater than the actual area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode.

30. The electrode device of claim 29, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

31. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient for delivering electrical therapy to the patient'"'"'s heart, each electrode having a conductive surface for contacting a patient'"'"'s skin, the conductive surface for contacting a patient'"'"'s skin having a shape and a perimeter; and

a skin interface,

wherein the shape of the conductive surface for contacting a patient'"'"'s skin of at least one electrode is selected so that when the at least one electrode is applied to a patient and used to deliver a therapeutically effective level of electrical therapy, the trans-thoracic impedance is less than the trans-thoracic impedance resulting when a conventional electrode applied to the same patient is used to deliver a therapeutically effective level of electrical therapy, wherein the conventional electrode has a continuous conductive surface for contacting a patient'"'"'s skin having an area equivalent to the area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode.

32. The electrode device of claim 31, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

33. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient for delivering electrical therapy to the patient, each electrode having a conductive surface for contacting a patient'"'"'s skin, each conductive surface for contacting a patient'"'"'s skin having a shape and a perimeter; and

a skin interface,

wherein the conductive surface for contacting a patient'"'"'s skin of at least one electrode is continuous and comprises at least two regions separated from one another by free space, wherein the regions are selected so that the shortest path between the two regions traverses the free space,

whereby the area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is less than the area of the conductive surface for contacting a patient'"'"'s skin that would be required for a conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin, wherein the conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin has an equivalent efficacy for delivery of electrical therapy to that of the at least one electrode.

34. The electrode device of claim 33, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

35. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient for delivering electrical therapy to the patient, each electrode having a conductive surface for contacting a patient'"'"'s skin, each conductive surface for contacting a patient'"'"'s skin having a shape and a perimeter; and

a skin interface,

wherein the conductive surface for contacting a patient'"'"'s skin of at least one electrode is continuous and comprises at least two regions separated from one another by free space, wherein the regions are selected so that the shortest path between the two regions traverses the free space,

whereby the effective conductive area of the at least one electrode is greater than the actual area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode.

36. The electrode device of claim 35, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

37. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient for delivering electrical therapy to the patient, each electrode having a conductive surface for contacting a patient'"'"'s skin having a shape and a perimeter; and

a skin interface,

wherein the conductive surface for contacting a patient'"'"'s skin of at least one electrode is continuous and comprises at least two regions separated from one another by free space, wherein the regions are selected so that the shortest path between the two regions traverses the free space,

whereby when the at least one electrode is applied to a patient and used to deliver a therapeutically effective level of electrical therapy, the trans-thoracic impedance is less than the trans-thoracic impedance resulting when a conventional electrode applied to the same patient is used to deliver a therapeutically effective level of electrical therapy, wherein the conventional electrode has a continuous conductive surface for contacting a patient'"'"'s skin having an area equivalent to the area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode.

38. The electrode device of claim 37, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

39. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient; and

a skin interface,

wherein the conductive surface for contacting a patient'"'"'s skin of at least one electrode is continuous and comprises at least two regions separated from one another by free space, wherein the regions are selected so that the shortest path between the two regions traverses the free space, and wherein the electrode device filter comprises at least one material selected to enhance the long-term wearability of the electrode device.

41. An electrode device for delivering electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient, each electrode having a conductive surface for contacting a patient'"'"'s skin; and

a skin interface,

wherein the perimeter of the conductive surface for contacting a patient'"'"'s skin of at least one electrode comprises at least one concave region.

44. An electrode device for application to the thorax for delivery of electrical therapy to a patient'"'"'s heart comprising:

a plurality of electrodes adapted for application to the thorax of a patient for delivery of electrical therapy to the patient'"'"'s heart; and

a skin interface,

wherein the electrode device comprises at least one material selected to enhance the long-term wearability of the electrode device, wherein the at least one material is selected from the group consisting of;

high MVTR adhesives, temperature-sensitive adhesives, and adhesives having a low peel strength.

45. The electrode device of claim 44, further including means for delivering electrical therapy sufficient for defibrillation or cardioversion.

64. An electrode comprising:

a conductor/wire assembly;

a skin interface optionally comprising a conductive hydrogel;

a top cover assembly comprising an insulating layer and an adhesive layer, wherein the insulating layer optionally comprises a foam pad, and wherein the adhesive layer optionally comprises a wearable adhesive and a flexible backing layer, and wherein at least one of the optional wearable adhesive and the optional flexible backing layer has a MVTR of approximately 300-1500 g/m² /day;

an applicator assembly comprising a top layer and a bottom layer, each layer having an upper and lower surface, wherein the lower surface of the bottom layer contacts the top cover assembly, and wherein the top layer comprises an adhesive, and wherein the bottom layer of the applicator assembly optionally contains cutouts that limit the amount of contact between the adhesive of the top layer and the top cover assembly of the electrode so that the top layer of the applicator is removable from the applicator assembly without damaging the electrode; and

a release liner assembly comprising a top layer and a bottom layer, each layer having an upper and lower surface, wherein the upper surface of the top layer contacts the skin interface.

65. A method for employing a segmented electrode device in conjunction with a cardiac defibrillator comprising the steps of:

providing a segmented electrode device comprising a plurality of electrodes, wherein each electrode comprises at least one electrode segment having a perimeter and a conductive surface for contacting a patient'"'"'s skin for delivering electrical therapy to the patient'"'"'s heart, and wherein at least one electrode comprises at least two electrode segments;

applying the at least one electrode comprising at least two electrode segments to the thorax of a patient in a spatial arrangement so that the effective conductive area of the at least two electrode segments is greater than the total combined area of the conductive surfaces for contacting a patient'"'"'s skin of the at least two electrode segments; and

applying the remaining electrodes of the segmented electrode device to the thorax of the patient.

66. The method of claim 65, wherein the providing step comprises providing means for delivering electrical therapy sufficient for defibrillation or cardioversion.

71. The method of any of claims 65, 66, 67, 68, 69, or 70, wherein the first applying step comprises applying at least one electrode comprising at least two electrode segments having a total area of the conductive surface for contacting a patient'"'"'s skin of less than 60 cm² to the thorax of a patient.

72. The method of any of claims 65, 66, 67, 68, 69, or 70, wherein the first applying step comprises applying at least one electrode comprising at least two electrode segments having a total area of the conductive surface for contacting a patient'"'"'s skin of less than 50 cm² to the thorax of a patient.

73. The method of any of claims 65, 66, 67, 68, 69, or 70, wherein the first applying step comprises applying at least one electrode comprising at least two electrode segments having a total area of the conductive surface for contacting a patient'"'"'s skin of less than 40 cm² to the thorax of a patient.

74. The method of any of claims 65, 66, 67, 68, 69, or 70, wherein the first applying step comprises applying at least one electrode comprising at least two electrode segments having a total area of the conductive surface for contacting a patient'"'"'s skin of less than 30 cm² to the thorax of a patient.

75. The method of any of claims 65, 66, 67, 68, 69, or 70, further comprising the step of:

replacing at least one electrode at intervals of greater than a day, wherein the replacing step comprises positioning at least one replacement electrode on the patient'"'"'s skin so that the position of the at least one replacement electrode does not substantially overlap with the positions of the original electrodes.

76. The method of any of claims 65, 66, 67, 68, 69, or 70, further comprising the step of:

moving at least one electrode at intervals of greater than a day, wherein the moving step comprises positioning the at least one electrode on the patient'"'"'s skin so that the new position of the at least one electrode does not substantially overlap with the previous position of the at the at least one electrode.

77. The method of claim 76, wherein the moving step comprises moving the at least one electrode to at least one predetermined position.

78. The method of any of claims 65, 66, 67, 68, 69, or 70, wherein the electrode device comprises at least one material selected to enhance the long-term wearability of the electrode device, and wherein the method further comprises the step of:

replacing at least one electrode at intervals of greater than a day, wherein the replacing step comprises positioning at least one replacement electrode on the patient'"'"'s skin in substantially the same position as the original at least one electrode.

79. The method of claim 78, wherein the at least one material is selected from the group consisting of:

high MVTR adhesives, temperature-sensitive adhesives, and adhesives having a low peel strength.

80. The method of any of claims 65, 66, 67, 68, 69, or 70, wherein the first applying step comprises arranging the at least two electrode segments so that the conductive surfaces for contacting a patient'"'"'s skin thereof are separated from each other on the patient by between 0.5 times the smallest effective diameter of any of the at least two electrode segments and 3.0 times the largest effective diameter of any of the at least two electrode segments.

81. The method of claim 80 further comprising the step of:

replacing at least one electrode at intervals of greater than a day, wherein the replacing step comprises positioning at least one replacement electrode on the patient'"'"'s skin so that the position of the at least one replacement electrode does not substantially overlap with the positions of the original electrodes.

82. The method of claim 80, wherein the electrode device comprises at least one material selected to enhance the long-term wearability of the electrode device, and wherein the method further comprises the step of:

replacing at least one electrode at intervals of greater than a day, wherein the replacing step comprises positioning at least one replacement electrode on the patient'"'"'s skin in substantially the same position as the original at least one electrode.

83. The method of claim 80, further comprising the step of:

moving at least one electrode at intervals of greater than a day, wherein the moving step comprises positioning the at least one electrode on the patient'"'"'s skin so that the new position of the at least one electrode does not substantially overlap with the previous position of the at least one electrode.

84. The method of claim 83, wherein the moving step comprises moving the at least one electrode to at least one predetermined position.

85. The method of claim 80, further comprising the step of treating the patient'"'"'s skin with a therapeutic or prophylactic agent before application of the electrodes.

86. The method of claim 80, wherein the providing step comprises providing an electrode device comprising a plurality of electrodes at least one of which comprises a therapeutic or prophylactic agent so as to treat a patient'"'"'s skin while the at least one electrode comprising a therapeutic or prophylactic agent is in contact with the patient'"'"'s skin.

87. The method of claim 80 further comprising the step of treating the patient'"'"'s skin with a therapeutic or prophylactic agent after removal of the electrodes.

88. The method of claim 80, wherein the providing step comprises providing an electrode device comprising at least one material selected to enhance long-term wearability of the electrode device.

99. The method of claim 96 or 88, wherein the replacing step comprises positioning the at least one replacement electrode on the patient in a predetermined position.

67. A method for employing a segmented electrode device in conjunction with a cardiac defibrillator comprising the steps of:

providing a segmented electrode device comprising a plurality of electrodes, wherein each electrode comprises at least one electrode segment having a perimeter and a conductive surface for contacting a patient'"'"'s skin for delivering electrical therapy to the patient, and wherein at least one electrode comprises at least two electrode segments;

applying the at least one electrode comprising at least two electrode segments to the thorax of a patient in a spatial arrangement so that when the at least one electrode comprising at least two spatially arranged electrode segments is used to deliver a therapeutically effective level of electrical therapy, the trans-thoracic impedance is less than the trans-thoracic impedance resulting when a conventional electrode applied to the same patient is used to deliver a therapeutically effective level of electrical therapy, wherein the conventional electrode has a continuous conductive surface for contacting a patient'"'"'s skin having an area equivalent to the total combined area of the conductive surfaces for contacting a patient'"'"'s skin of the at least two electrode segments; and

applying the remaining electrodes of the segmented electrode device to the thorax of the patient.

68. The method of claim 67, wherein the providing step comprises providing means for delivering electrical therapy and wherein the therapeutically effective level of electrical therapy is sufficient for defibrillation or cardioversion.

69. A method for employing a segmented electrode device in conjunction with a cardiac defibrillator comprising the steps of:

providing a segmented electrode device comprising a plurality of electrodes, wherein each electrode comprises at least one electrode segment having a perimeter and a conductive surface for contacting a patient'"'"'s skin for delivering electrical therapy to the patient, and wherein at least one electrode comprises at least two electrode segments;

applying the at least one electrode comprising at least two electrode segments to the thorax of a patient in a spatial arrangement so that the total combined area of the conductive surfaces for contacting a patient'"'"'s skin of the electrode segments is less than the area of the conductive surface for contacting a patient'"'"'s skin that would be required for a conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin, wherein the conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin has an equivalent efficacy for delivering electrical therapy to that of the at least one electrode; and

applying the remaining electrodes of the segmented electrode device to the thorax of the patient.

70. The method of claim 69, wherein the providing step comprises providing means for delivering electrical therapy, and wherein the at least one electrode and the conventional electrode have an equivalent efficacy for delivering electrical therapy sufficient for defibrillation or cardioversion.

89. A method for employing an electrode device in conjunction with a cardiac defibrillator comprising the steps of:

providing an electrode device comprising a plurality of electrodes each having a conductive surface for contacting a patient'"'"'s skin, the electrodes being adapted for delivering electrical therapy to the patient'"'"'s heart;

applying at least two of the electrodes to the thorax of the patient; and

replacing the at least two of the electrodes at intervals of greater than a day.

90. The method of claim 89, wherein the replacing step comprises positioning the replacement electrodes on the patient'"'"'s skin so that the positions of the replacement electrodes do not substantially overlap with the positions of the original electrodes.

91. The method of claim 89, wherein the replacing step comprises positioning the at least one replacement electrode on the patient in a predetermined position.

92. The method of claim 89, wherein the providing step comprises providing an electrode device comprising at least one material selected to enhance the long-term wearability of the electrode device, and wherein the replacing step comprises positioning at least one replacement electrode on the patient'"'"'s skin in substantially the same position as the original at least one electrode.

93. The method of claim 89, wherein the providing step comprises providing an electrode device comprising at least one material selected from the group consisting of:

high MVTR adhesives, temperature-sensitive adhesives, and adhesives having a low peel strength.

94. A method for employing an electrode device in conjunction with a cardiac defibrillator comprising the steps of:

providing an electrode device comprising a plurality of electrodes each having a conductive surface for contacting a patient'"'"'s skin, the electrodes being adapted for delivering electrical therapy to the patient'"'"'s heart;

applying at least two of the electrodes to the thorax of the patient; and

moving the at least two electrodes at intervals of greater than a day, wherein the moving step comprises positioning the at least two electrodes on the patient'"'"'s skin so that the new poistions of the at least two electrodes do not substantially overlap with the previous positions of the at least two electrodes.

95. The method of claim 94, wherein the moving step comprises moving the at least one electrode to at least one predetermined positions.

96. A method for employing an electrode device in conjunction with a cardiac defibrillator comprising the steps of:

applying at least two electrodes to the thorax of a patient, each electrode having a conductive surface for contacting a patient'"'"'s skin having a shape and a perimeter, wherein the shape of the conductive surface for contacting a patient'"'"'s skin of at least one electrode is selected so that the area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is less than the area of the surface for contacting a patient'"'"'s skin that would be required for a conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin, wherein the conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin has an equivalent efficacy for delivering electrical therapy to that of the at least one electrode; and

replacing at least one of the at least two electrodes at intervals of greater than a day.

97. The method of claim 96, wherein the replacing step comprises replacing the at least one electrode so that the new position of the at least one electrode interlocks with the previous position of the at least one electrode.

98. The method of claim 96, further comprising the step of providing means for delivering electrical therapy, and wherein the at least one electrode and the conventional electrode have an equivalent efficacy for delivering electrical therapy sufficient for defibrillation or cardioversion.

100. The method of claim 96, further comprising the step of providing an electrode device comprising at least one material selected to enhance the long-term wearability of the electrode device, and wherein the replacing step comprises positioning at least one replacement electrode on the patient'"'"'s skin in substantially the same position as the original at least one electrode.

101. The method of claim 96, wherein the replacing step comprises positioning the replacement electrodes on the patient'"'"'s skin so that the positions of the replacement electrodes do not substantially overlap with the positions of the original electrodes.

102. The method of claim 101, wherein the applying step comprises applying at least one electrode comprising at least one material selected from the group consisting of:

high MVTR adhesives, temperature-sensitive adhesives, and adhesives having a low peel strength.

103. A method for employing an electrode device in conjunction with a cardiac defibrillator comprising the steps of:

applying at least two electrodes to the thorax of a patient, each electrode having a conductive surface for contacting a patient'"'"'s skin having a shape and a perimeter, wherein the shape of the conductive surface for contacting a patient'"'"'s skin of at least one electrode is selected so that the area of the conductive surface for contacting a patient'"'"'s skin of the at least one electrode is less than the area of the surface for contacting a patient'"'"'s skin that would be required for a conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin, wherein the conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin has an equivalent efficacy for delivering electrical therapy to that of the at least one electrode; and

moving at least one of the at least two electrodes at intervals of greater than a day, wherein the moving step comprises positioning the electrodes on the patient'"'"'s skin so that the new position of the at least one electrode do not substantially overlap with the previous positions of the at least one electrode.

104. The method of claim 103, wherein the moving step comprises moving the at least one electrode to a position that interlocks with the previous position of the at least one electrode.

105. The method of claim 103, wherein the moving step comprises moving the at least one electrode to at least one predetermined position.

106. The method of claim 103, further comprising the step of providing means for delivering electrical therapy and wherein the conventional electrode with a continuous conductive surface for contacting a patient'"'"'s skin has an equivalent efficacy for delivering electrical therapy sufficient for defibrillation or cardioversion to that of the at least one electrode.

107. The method of any of claims 65, 66, 67, 68, 69, 70, 89, 94, 96, 98, 103, or 106, further comprising the step of treating the patient'"'"'s skin with a therapeutic or prophylactic agent before application of the electrodes.

108. The method of any of claims 65, 66, 67, 68, 69, 70, 89, 94, 96, 98, 103, or 106, wherein at least one applying step comprises applying at least one electrode that comprises a therapeutic or prophylactic agent so as to treat a patient'"'"'s skin while the at least one electrode comprising a therapeutic or prophylactic agent is in contact with the patient'"'"'s skin.

109. The method of any of claims 65, 66, 67, 68, 69, 70, 89, 94, 96, 98, 103, or 106 further comprising the step of treating the patient'"'"'s skin with a therapeutic or prophylactic agent after removal of the electrodes.

110. The method of any of claims 65, 66, 67, 68, 69, 70, 89, 94, 96, 98, 103, or 106, wherein at least one applying step comprises applying at least one electrode that comprises at least one material selected to enhance long-term wearability of the electrode device.