Subcutaneous only implantable cardioverter defibrillator and optional pacer

• US 6,721,597 B1
• Filed: 09/18/2000
• Issued: 04/13/2004
• Est. Priority Date: 09/18/2000
• Status: Expired due to Term

• Current Assignee: Cameron Incorporated (Schlumberger NV)
• Original Assignee: Cameron Incorporated (Schlumberger NV)
• Inventors: Bardy, Gust H., Cappato, Riccardo
• Primary Examiner(s): Schaetzle, Kennedy
• Assistant Examiner(s): DROESCH, KRISTEN L
• Application Number:
  US09/663,607
• Time in Patent Office: 1,303 Days
• Field of Search: 600/372-375, 600/377, 606/129, 607/4-8, 607/115-116, 607/119, 607/121, 607/129, 607/130-131, 128/898
• US Class Current: 607/4
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/29 for permanent or long-term implantation
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 1/3906 characterised by the form of the shockwave
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

A subcutaneous implantable cardioverter-defibrillator is disclosed which has an electrically active canister which houses a source of electrical energy, a capacitor, and operational circuitry that senses the presence of potentially fatal heart rhythms. At least one subcutaneous electrode that serves as the opposite electrode from the canister is attached to the canister via a lead system Cardioversion-defibrillation energy is delivered when the operational circuitry senses a potentially fatal heart rhythm. There are no transvenous, intracardiac, or epicardial electrodes. A method of subcutaneously implanting the cardioverter-defibrillator is also disclosed as well as a kit for conducting the method.

Claims

1. A method of implanting a subcutaneous cardioverter-defibrillator in a patient comprising the steps of;

making only one skin incision in the thoracic region of the patient;

inserting a curved introducer through the skin incision to make a subcutaneous path in the thoracic region such that the path terminates subcutaneously at a location that if a straight line were drawn from the skin incision to the path termination the line would intersect the heart of the patient;

implanting an electrode subcutaneously at the path termination point;

placing an electrically active canister subcutaneously at the skin incision point wherein the canister contains a source of electrical energy and operational circuitry that senses the presence of potentially fatal heart rhythms and has means for delivering electrical cardioversion-defibrillation energy using the canister as either the anode or the cathode and using the electrode as the opposite electrode from the canister, and wherein the canister is electrically connected to the electrode; and

closing the skin incision.

2. The method of implanting a subcutaneous cardioverter-defibrillator of claim 1 further comprising the step of injecting a local anesthetic through the curved introducer.

3. The method of implanting a subcutaneous cardioverter-defibrillator of claim 1 wherein the skin incision is located in the left anterior axillary line approximately at the level of the patient'"'"'s cardiac apex.

4. The method of implanting a subcutaneous cardioverter-defibrillator of claim 3 wherein the electrode is subcutaneously implanted in the left posterior axillary line lateral to the left scapula.

5. The method of implanting a subcutaneous cardioverter-defibrillator of claim 3 wherein the canister is subcutaneously implanted in the left inframammary crease of the patient.

6. The method of implanting a subcutaneous cardioverter-defibrillator of claim 1 wherein the skin incision is located in the left posterior axillary line of the patient approximately at a level lateral to the tip of the left scapula of the patient.

7. The method of implanting a subcutaneous cardioverter-defibrillator of claim 6 wherein the electrode is implanted in the anterior precordial region of the patient.

8. The method of implanting a subcutaneous cardioverter-defibrillator of claim 7 wherein the electrode is implanted in the inframammary crease of the patient.

9. The method of implanting a subcutaneous cardioverter-defibrillator of claim 1 wherein the operational circuitry can detect the presence of bradycardia rhythms.

10. The method of implanting a subcutaneous cardioverter-defibrillator of claim 9 wherein the device has means of delivering electrical cardiac pacing energy when the operational circuitry senses a bradycardia rhythm.

51. The subcutaneous implantable cardioverter-defibrillator of claim 1 wherein the operational circuitry comprises an impedance detection means for measuring the undulations in transthoracic impedance created during respiration.

52. The subcutaneous implantable cardioverter-defibrillator of claim 51 wherein the operational circuitry can also measure the cardiac output using transthoracic impedance.

11. A method for providing anti-arrhythmia therapy via a subcutaneous cardioverter-defibrillator, comprising:

implanting a canister comprising a biocompatible housing subcutaneously in a patient in the anterior thorax approximately level with the inframammary crease, the biocompatible housing enclosing and containing cardioversion-defibrillation circuitry and defining at least one electrically conductive surface on an outer surface of the biocompatible housing and electrically connected to the cardioversion-defibrillation circuitry;

implanting an electrically inert lead subcutaneously in the posterolateral thorax extending circumferentially around the thorax to a position approximately lateral to the tip of the left inferior portion of the scapula, the electrically inert lead comprising a substantially pliant and directable cannula adaptably connected to the canister with a lead electrode formed on a distal end of the electrically inert lead and electrically interfaced to the cardioversion-defibrillation circuitry; and

delivering an electrical therapy comprising an anti-arrhythmia waveform from the lead electrode to the at least one electrically conductive surface.

12. A method according to claim 11, further comprising:

at least one further electrically inert lead comprising a substantially pliant and directable cannula connected on the proximal end to the canister;

at least one further lead electrode formed on a distal end of the at least one further electrically inert lead and electrically interfaced to the cardioversion-defibrillation circuitry; and

switching circuitry to selectively deliver an electrical therapy between the at least one electrically conductive surface and one or more of the lead electrodes on the electrically inert leads.

13. A method according to claim 12, further comprising:

fixedly attaching the distal end of one or more of the electrically inert leads to tissue in the left posterolateral thorax to form a secured lead implantation.

14. A method according to claim 11, further comprising:

providing a plurality of sensing electrodes formed on the electrically inert lead, each sensing electrode interfacing with sensing circuitry in the cardioversion-defibrillation circuitry; and

monitoring and deriving cardiac physiological measures relating to at least one of QRS signal morphology, QRS signal frequency content, QRS R-R interval stability data, and QRS amplitude characteristics via the sensing electrodes.

15. A method according to claim 11, further comprising:

fixedly attaching the distal end of the at least one electrically inert lead to tissue in the left posterolateral thorax to form a secured lead implantation.

16. A method according to claim 11, further comprising:

implanting a plurality of pliant bends formed in the electrically inert lead subcutaneously in the thorax transverse to the inframammary crease to form a serpiginous lead implantation.

17. A method according to claim 11, further comprising:

generating low amplitude voltage on a T-wave of an ECG via the at least one electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry.

18. A method for providing anti-arrhythmia therapy via a posterolateral implanted subcutaneous cardioverter-defibrillator, comprising:

implanting a canister comprising a biocompatible housing subcutaneously in a patient to a position approximately lateral to the left scapula, the biocompatible housing enclosing and containing cardioversion-defibrillation circuitry and defining at least one electrically conductive surface on an outer surface of the biocompatible housing and electrically connected to the cardioversion-defibrillation circuitry;

implanting an electrically inert lead subcutaneously in the anterior thorax extending around the thorax approximately level with the inframammary crease, the electrically inert lead comprising a substantially pliant and directable cannula adaptably connected to the canister with a lead electrode formed on a distal end of the electrically inert lead and electrically interfaced to the cardioversion-defibrillation circuitry; and

delivering an electrical therapy comprising an anti-arrhythmia waveform from the lead electrode to the at least one electrically conductive surface.

19. A method of implanting a subcutaneous cardioverter-defibrillator in a patient comprising the steps of;

making only one skin incision in the left anterior axillary line approximately at the level of the patient'"'"'s cardiac apex;

inserting a curved introducer through the skin incision to make a subcutaneous path in the thoracic region such that the path terminates subcutaneously at a location that if a straight line were drawn from the skin incision to the path termination the line would intersect the heart of the patient;

implanting an electrode subcutaneously at the path termination point;

placing an electrically active canister subcutaneously at the skin incision point and implanting it subcutaneously implanted in the left inframammary crease of the patient, wherein the canister contains a source of electrical energy and operational circuitry that senses the presence of potentially fatal heart rhythms and has means for delivering electrical cardioversion-defibrillation energy using the canister as either the anode or the cathode and using the electrode as the opposite electrode from the canister, and wherein the canister is electrically connected to the electrode; and

closing the skin incision.

20. A method of implanting a subcutaneous cardioverter-defibrillator in a patient comprising the steps of;

making only one skin incision in in the left posterior axillary line of the patient approximately at a level lateral to the tip of the left scapula of the patient;

inserting a curved introducer through the skin incision to make a subcutaneous path in the thoracic region such that the path terminates subcutaneously at a location that if a straight line were drawn from the skin incision to the path termination the line would intersect the heart of the patient;

implanting an electrode subcutaneously at the path termination point;

placing an electrically active canister subcutaneously at the skin incision point,

wherein the canister contains a source of electrical energy and operational circuitry that senses the presence of potentially fatal heart rhythms and has means for delivering electrical cardioversion-defibrillation energy using the canister as either the anode or the cathode and using the electrode as the opposite electrode from the canister, and wherein the canister is electrically connected to the electrode; and

closing the skin incision.

21. A subcutaneous implantable cardioverter-defibrillator comprising:

an electrically active canister that serves as either an anode or a cathode of the cardioverter-defibrillator wherein the canister houses a source of electrical energy, a capacitor, and operational circuitry that senses the presence of potentially fatal heart rhythms;

a subcutaneous electrode that serves as the opposite electrode from the canister (either the anode or the cathode);

a lead system electrically attaching the electrode to the canister;

means for delivering electrical cardioversion-defibrillation energy when the operational circuitry senses a potentially fatal heart rhythm; and

the absence of a transvenous, intracardiac, or epicardial electrode.

22. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the electrical cardioversion-defibrillating voltage is equal to or greater than 800 Volts.

23. The subcutaneous implantable cardioverter-defibrillator of claim 22 wherein the electrical cardioversion-defibrillating voltage ranges from about 800 volts to about 2000 volts.

24. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the electrical cardioversion-defibrillating energy ranges from about 40 Joules to about 150 Joules.

25. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the subcutaneous electrode is a composite electrode comprising:

a cardioversion-defibrillation electrode;

a first sensing electrode; and

a second sensing electrode electrically insulated and spaced apart from the first sensing electrode.

26. The subcutaneous implantable cardioverter-defibrillator of claim 25 wherein the first sensing electrode is located at a distal end of the subcutaneous electrode, the second sensing electrode is located about 1 to about 10 cm proximal to the first sensing electrode, and the cardioversion-defibrillation electrode is located proximal to the second sensing electrode.

27. The subcutaneous implantable cardioverter-defibrillator of claim 26 wherein the first and second sensing electrodes are spaced apart by about 4 cm.

28. The subcutaneous implantable cardioverter-defibrillator of claim 25 wherein the first sensing electrode is located at a distal end of the subcutaneous electrode, the cardioversion-defibrillation electrode is located proximal to the first sensing electrode, and the second sensing electrode is located proximal to the cardioversion-defibrillation sensing electrode.

29. The subcutaneous implantable cardioverter-defibrillator of claim 25 wherein the cardioversion-defibrillation electrode is located at a distal end of the subcutaneous electrode, the first sensing electrode is located proximally to the cardioversion-defibrillation electrode, and the second sensing electrode is located about 1 to about 10 cm proximal to the first sensing electrode.

30. The subcutaneous implantable cardioverter-defibrillator of claim 29 wherein the first and second sensing electrodes are spaced apart by about 4 cm.

31. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the operational circuitry can also sense the presence of bradycardia rhythm.

32. The subcutaneous implantable cardioverter-defibrillator of claim 31 further comprising means for delivering cardiac pacing energy when the operational circuitry senses a bradycardia rhythm.

33. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the operational circuitry is programmable.

34. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the operational circuitry can detect tachycardia.

35. The subcutaneous implantable cardioverter-defibrillator of claim 34 further comprising means for delivering antitachycardia pacing when the operational circuitry senses a tachycardia rhythm.

36. The subcutaneous implantable cardioverter-defibrillator of claim 34 wherein the operational circuitry detects ventricular tachycardia that is greater than 240 beats per minute.

37. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the operational circuitry can detect atrial tachycardia and atrial fibrillation.

38. The subcutaneous implantable cardioverter-defibrillator of claim 37 wherein the operational circuitry can deliver defibrillation energy to treat the detected atrial fibrillation.

39. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the operational circuitry can induce ventricular tachycardia or ventricular fibrillation.

40. The subcutaneous implantable cardioverter-defibrillator of claim 39 wherein the ventricular tachycardia or ventricular fibrillation is induced by shocks on the T wave.

41. The subcutaneous implantable cardioverter-defibrillator of claim 39 wherein the ventricular tachycardia or ventricular fibrillation is induced by low direct current voltage applied during the entire cardiac cycle.

42. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the electrical cardioversion-defibrillating energy is delivered in a biphasic wave form.

43. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the capacitor has a capacitance of about 50 to about 200 μ

F.

44. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the canister is malleable.

45. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the canister is provided with at least one sensing electrode.

46. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the canister is provided with one or more sensing electrodes, the subcutaneous electrode is provided with one or more sensing electrodes, and means for selecting two sensing electrodes from the one or more sensing electrodes located on the canister and the one or more sensing electrodes located on the subcutaneous electrode that provide adequate QRS wave detection.

47. The subcutaneous implantable cardioverter-defibrillator of claim 21 comprising an additional subcutaneous electrode that serves as the opposite electrode from the canister (either the anode or the cathode) and the same polarity as the original subcutaneous electrode.

48. The subcutaneous implantable cardioverter-defibrillator of claim 21 comprising an additional subcutaneous electrode that serves as the opposite electrode from the original subcutaneous electrode (either the anode or the cathode) and the same polarity as the canister.

49. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the electrical cardioversion-defibrillating energy is delivered for about 10 to about 20 milliseconds total duration in form of a biphasic pulse having an initial positive phase followed by a negative phase, with the initial positive phase containing approximately ⅔

of the energy delivered.

50. The subcutaneous implantable cardioverter-defibrillator of claim 21 further comprising an attachment member located at the distal end of the subcutaneous electrode for attaching the subcutaneous electrode to nearby tissue.

53. The subcutaneous implantable cardioverter-defibrillator of claim 21 wherein the canister is long, thin, and curved such that it is shaped to be subcutaneously implanted adjacent to and parallel with ribs of a patient.

54. A cardioverter-defibrillator for subcutaneous implantation, comprising:

a canister comprising a biocompatible housing enclosing and containing cardioversion-defibrillation circuitry and defining at least one electrically conductive surface on an outer surface of the biocompatible housing and electrically connected to the cardioversion-defibrillation circuitry;

an electrically inert lead comprising a substantially pliant and directable cannula adaptably connected to the canister; and

a lead electrode formed on a distal end of the electrically inert lead and electrically interfaced to the cardioversion-defibrillation circuitry to deliver an electrical therapy with the at least one electrically conductive surface to the heart of a patient without a transvenous, intracardiac or epicardial electrode.

55. A cardioverter-defibrillator according to claim 54, further comprising:

at least one sensing electrode formed on and electrically insulated from the at least one electrically conductive surface and electrically interfaced to the cardioversion-defibrillation circuitry.

56. A cardioverter-defibrillator according to claim 54, further comprising:

at least one electrically insulated surface defined on the outer surface of the biocompatible housing and juxtaposed to the at least one electrically conductive surface.

57. A cardioverter-defibrillator according to claim 56, further comprising:

at least one sensing electrode formed on the at least one electrically insulated surface and electrically interfaced to the cardioversion-defibrillation circuitry.

58. A cardioverter-defibrillator according to claim 56, further comprising:

a focused margin bounding the at least one electrically conductive surface from the at least one electrically insulated surface and defining a concentrated electrically conductive surface within the at least one electrically insulated surface.

59. A cardioverter-defibrillator according to claim 54, further comprising:

monitoring circuitry integral to the cardioversion-defibrillation circuitry and deriving physiological measures relating to at least one of QRS signal morphology, QRS signal frequency content, QRS R-R interval stability data, and QRS amplitude characteristics.

60. A cardioverter-defibrillator according to claim 54, further comprising:

a pulse generator integral to the cardioversion-defibrillation circuitry and producing an anti-arrhythmia waveform for anti-arrhythmia therapy via the at least one electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry.

61. A cardioverter-defibrillator according to claim 60, further comprising:

the pulse generator generating the anti-arrhythmia waveform as a biphasic waveform with characteristics comprising at least one of a waveform generated from a capacitor having a capacitance between approximately 50 μ

F and 200 μ

F, a voltage between approximately 800 V and 2000 V, an energy between 40 J and 150 J, and a duration between approximately 5 msec to 25 msec.

62. A cardioverter-defibrillator according to claim 61, further comprising:

the cardioversion-defibrillation circuitry initiating the anti-arrhythmia therapy upon a cardiac ventricular rate of around 240 bpm sustained over an at least 4 second interval.

63. A cardioverter-defibrillator according to claim 61, further comprising:

the cardioversion-defibrillation circuitry confirming the anti-arrhythmia therapy upon a -cardiac ventricular rate of around 240 bpm sustained over an approximately 1 second interval.

64. A cardioverter-defibrillator according to claim 61, further comprising:

the cardioversion-defibrillation circuitry terminating the anti-arrhythmia therapy upon a cardiac ventricular rate of around 240 bpm sustained over an at least 4 second interval.

65. A cardioverter-defibrillator according to claim 54, further comprising:

pacing circuitry operatively conjunctive to the cardioversion-defibrillation circuitry which generates at least one of an anti-bradycardia and an anti-tachycardia pacing waveform via the at least one electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry.

66. A cardioverter-defibrillator according to claim 54, further comprising:

induction circuitry integral to the cardioversion-defibrillation circuitry which delivers a voltage on a T-wave of an ECG via the at least one electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry.

67. A cardioverter-defibrillator according to claim 54, further comprising:

a radian bend continuously formed approximately axial to the biocompatible housing.

68. A cardioverter-defibrillator according to claim 67, further comprising:

a cross-section defined approximately transverse to the biocompatible housing and comprising at least one of a square and rectangular shapes.

69. A cardioverter-defibrillator according to claim 54, further comprising:

at least one of a fractalized and a wrinkled surface formed on the outer surface of the biocompatible housing.

70. A cardioverter-defibrillator according to claim 54, wherein the biocompatible housing is constructed from at least one of a titanium alloy and other biocompatible material, such material being malleable.

71. A cardioverter-defibrillator according to claim 54, further comprising:

monitoring circuitry integral to the cardioversion-defibrillation circuitry and obtaining physiological measures via at least one of the lead electrode and the at least one electrically conductive surface.

72. A cardioverter-defibrillator according to claim 54, further comprising:

the lead electrode formed non-circumferentially on the electrically inert lead and with an overall length of an electrically active component of less than approximately 10 cm.

73. A cardioverter-defibrillator according to claim 54, further comprising:

the lead electrode interfacing with high voltage and low impedance circuitry.

74. A cardioverter-defibrillator according to claim 73, further comprising:

a plurality of sensing electrodes formed on the electrically inert lead, each sensing electrode interfacing with low voltage and high impedance circuitry.

75. A cardioverter-defibrillator according to claim 74, further comprising:

each such sensing electrode formed distal to the lead electrode.

76. A cardioverter-defibrillator according to claim 74, further comprising:

each such sensing electrode formed proximal to the lead electrode.

77. A cardioverter-defibrillator according to claim 74, further comprising:

at least one such sensing electrode formed distal to the lead electrode and at least one such sensing electrode formed proximal to the lead electrode.

78. A cardioverter-defibrillator according to claim 74, further comprising:

at least one such sensing electrode formed non-circumferentially on the electrically inert lead.

79. A cardioverter-defibrillator according to claim 54, further comprising:

at least one further electrically inert lead comprising a substantially pliant and directable cannula connected on the proximal end to the canister;

at least one further lead electrode formed on a distal end of the at least one further electrically inert lead and electrically interfaced to the cardioversion-defibrillation circuitry; and

switching circuitry to selectively deliver an electrical therapy between the at least one electrically conductive surface and one or more of the lead electrodes on the electrically inert leads.

80. A cardioverter-defibrillator according to claim 54, further comprising:

a plurality of pliant bends formed in the electrically inert lead to form a serpiginous lead implantation.

81. A cardioverter-defibrillator according to claim 54, further comprising:

an anchor segment fixedly attached to the distal end of the electrically inert lead to form a secured lead implantation.

85. A subcutaneous cardioverter-defibrillator according to claim 81, further comprising:

at least one electrically insulated surface defined about a surface of the biocompatible housing adapted to face away from the heart and juxtaposed to the at least one electrically conductive surface.

86. A subcutaneous cardioverter-defibrillator according to claim 85, further comprising:

an insulating area substantially interposed between the at least one electrically conductive surface and the at least one electrically insulated surface.

82. A subcutaneous cardioverter-defibrillator with electrically active canister for minimally invasive implantation, comprising:

a subcutaneously implantable, canister comprising a sterilizable biocompatible housing enclosing and containing cardioversion-defibrillation circuitry interfaceable through the biocompatible housing via an electrically isolated connector block, the biocompatible housing defining at least one electrically conductive surface on the outer surface of the biocompatible housing and electrically connected to the cardioversion-defibrillation circuitry;

an electrically inert lead comprising a substantially pliant and directable cannula enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block; and

a lead electrode formed on a distal end of the electrically inert lead and electrically interfaced via the one or more conductors to the cardioversion-defibrillation circuitry to deliver an electrical therapy with the at least one electrically conductive surface to the heart of a patient without a transvenous, intracardiac or epicardial electrode.

83. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

the lead electrode further interfacing with sensing circuitry and providing a sensing function to the cardioversion-defibrillation circuitry.

84. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

a concentrated electrically conductive surface defined about a surface of the biocompatible housing adapted to face the heart.

87. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

at least one sensing electrode formed on and electrically insulated from the at least one electrically conductive surface and electrically interfaced to the cardioversion-defibrillation circuitry, each sensing electrode interfacing with sensing circuitry and providing a sensing function to the cardioversion-defibrillation circuitry.

88. A subcutaneous cardioverter-defibrillator according to claim 87, further comprising:

an electrically insulated surface about each at least one sensing electrode abutting the biocompatible housing and marginal to the at least one electrically conductive surface.

89. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

a plurality of sensing electrodes formed on the electrically inert lead and electrically interfaced via the one or more conductors to the cardioversion-defibrillation circuitry, each sensing electrode interfacing with sensing circuitry and providing a sensing function to the cardioversion-defibrillation circuitry.

90. A subcutaneous cardioverter-defibrillator according to claim 89, further comprising:

each of the sensing electrodes formed in locations comprising at least one of a location distal to the lead electrode, proximal to the lead electrode, and in juxtaposition to the lead electrode.

91. A subcutaneous cardioverter-defibrillator according to claim 89, further comprising:

at least one such sensing electrode formed non-circumferentially along an interior surface of the electrically inert lead.

92. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

a radian bend continuously formed approximately axial to the biocompatible housing.

93. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

at least one further electrically inert lead comprising a substantially pliant and directable cannula enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block;

at least one further lead electrode formed on a distal end of the at least one further electrically inert lead and electrically interfaced via the one or more conductors to the cardioversion-defibrillation circuitry to deliver an electrical therapy to the at least one electrically conductive surface; and

switching circuitry controllable via the cardioversion-defibrillation circuitry to selectively deliver an electrical therapy between the at least one electrically conductive surface and one or more of the lead electrodes on the electrically inert leads.

94. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

an anchor segment comprising an electrically inert anchoring device fixedly attached to the distal end of the electrically inert lead to form a secured lead implantation within soft tissue.

95. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

a pulse generator integral to the cardioversion-defibrillation circuitry and generating an anti-arrhythmia biphasic waveform with characteristics comprising at least one of a waveform generated from a capacitor having a capacitance between approximately 50 μ

F and 200 μ

F, a voltage between approximately 800 V and 2000 V, an energy between 40 J and 150 J, and a duration between approximately 5 msec to 25 msec.

96. A subcutaneous cardioverter-defibrillator according to claim 82, further comprising:

the cardioversion-defibrillation circuitry comprising at least one of;

monitoring circuitry deriving physiological measures relating to at least one of QRS signal morphology, QRS signal frequency content, QRS R-R interval stability data, and QRS amplitude characteristics;

a pulse generator producing an anti-arrhythmia waveform for anti-arrhythmia therapy via the at least one electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry;

pacing circuitry operatively conjunctive to the cardioversion-defibrillation circuitry which generates at least one of an anti-bradycardia and an anti-tachycardia pacing waveform via the at least one electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry; and

induction circuitry generating low amplitude voltage on a T-wave of an ECG via the at least one electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry.

97. A subcutaneous cardioverter-defibrillator according to claim 82, wherein the biocompatible housing is constructed from at least one of a titanium alloy and another biocompatible material, such material being malleable, and the electrically inert lead is constructed from at least one of a silicon, polyurethane, ceramic, and similarly characteristic biocompatible material.

98. A cardioversion-defibrillation device with electrically conductive housing means for subcutaneous implantation, comprising:

means for housing and hermetically containing cardioversion-defibrillation circuitry, the housing means comprising electrically isolated means for externally interfacing to the cardioversion-defibrillation circuitry and defining at least one electrically conductive surface on an outer surface of the housing means that is electrically connected to the cardioversion-defibrillation circuitry through internal interfacing means;

means for guiding and enclosing one or more conductors connected to the cardioversion-defibrillation circuitry via the external interfacing means, the enclosing means being substantially pliant and directable; and

means for delivering an electrical therapy to a patient'"'"'s heart between a distal end of the guiding means and the at least one electrically conductive surface without a transvenous, intracardiac or epicardial electrode, the electrical therapy delivering means being responsive to an autonomously detected arrhythmic condition and being electrically connected via the one or more conductors to the cardioversion-defibrillation circuitry.

99. A cardioversion-defibrillation device according to claim 98, further comprising:

means for monitoring and deriving physiological measures relating to at least one of QRS signal morphology, QRS signal frequency content, QRS R-R interval stability data, and QRS amplitude characteristics;

means for producing an anti-arrhythmia waveform for anti-arrhythmia therapy via the at least one electrically conductive surface and the electrical therapy delivering means responsive to the cardioversion-defibrillation circuitry;

means for pacing circuitry operatively conjunctive to the cardioversion-defibrillation circuitry which generates at least one of an anti-bradycardia and an anti-tachycardia pacing waveform via the at least one electrically conductive surface and the electrical therapy delivering means responsive to the cardioversion-defibrillation circuitry; and

means for induction circuitry generating low amplitude voltage on a T-wave of an ECG via the at least one electrically conductive surface and the electrical therapy delivering means responsive to the cardioversion-defibrillation circuitry.

100. A cardioversion-defibrillation device according to claim 98, further comprising:

sensing means provided via the electrical therapy delivering means, the sensing means being electrically connected via the one or more conductors to the cardioversion-defibrillation circuitry to interface with sensing circuitry.

101. A cardioversion-defibrillation device according to claim 98, further comprising:

sensing means provided abutting and electrically insulated from the housing means, the sensing means being electrically connected via the internal interfacing means to the cardioversion-defibrillation circuitry to interface with sensing circuitry.

102. A cardioversion-defibrillation device according to claim 98, further comprising:

sensing means provided on the guiding means adjunctively to the electrical therapy delivering means, the sensing means being electrically connected via the one or more conductors to the cardioversion-defibrillation circuitry to interface with sensing circuitry.

103. A subcutaneous cardioverter-defibrillator according to claim 98, further comprising:

sensing means formed in locations comprising at least one of a location distal to the electrical therapy delivering means, proximal to the electrical therapy delivering means, and in juxtaposition to the electrical therapy delivering means.

104. A cardioversion-defibrillation device according to claim 99, further comprising:

at least one electrically insulated surface defined about a surface of the housing means adapted to face the heart and juxtaposed to the at least one electrically conductive surface, an insulating area being substantially interposed between the at least one electrically conductive surface and the at least one electrically insulated surface.

105. A cardioversion-defibrillation device according to claim 98, further comprising:

pulse generating means integral to the cardioversion-defibrillation circuitry and generating an anti-arrhythmia biphasic waveform with characteristics comprising at least one of a waveform generated from a capacitor having a capacitance between approximately 50 μ

F and 200 μ

F, a voltage between approximately 800 V and 2000 V, an energy between 40 J and 150 J, and a duration between approximately 5 msec to 25 msec.

106. A cardioversion-defibrillation device according to claim 98, further comprising:

a radian bend continuously formed approximately axial to the housing means.

107. A cardioversion-defibrillation device according to claim 98, further comprising:

anchoring means fixedly attached to the distal end of the guiding means to form a secured lead implantation within soft tissue.

108. An implantable subcutaneous cardioverter-defibrillator with electrically active canister, comprising:

an implantable canister providing a housing enclosing and containing cardioversion-defibrillation circuitry externally interfaceable via an electrically isolated connector block on a proximal end of the housing, the housing defining a discrete electrically conductive surface on an outer surface and internally connecting electrically to the cardioversion-defibrillation circuitry;

a substantially pliant and directable lead enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block, the lead being electrically inert; and

a lead electrode circumferentially formed on a distal end of the lead and electrically interfaced via the one or more conductors to the cardioversion-defibrillation circuitry to deliver an electrical therapy responsive to an autonomously detected arrhythmic condition without a transvenous, intracardiac or epicardial electrode.

109. An implantable subcutaneous cardioverter-defibrillator according to claim 108, further comprising:

an electrically insulated surface juxtaposed to the discrete electrically conductive surface and substantially interposed therefrom by an electrically insulated area.

110. An implantable subcutaneous cardioverter-defibrillator according to claim 108, further comprising:

a plurality of sensing electrodes circumferentially formed on the lead and electrically connected with the one or more conductors via the isolated connector block to the cardioversiondefibrillation circuitry, each of the sensing electrodes interfacing with sensing circuitry within the cardioversion-defibrillation circuitry and providing a sensing function.

111. An implantable subcutaneous cardioverter-defibrillator according to claim 110, further comprising:

each of the sensing electrodes formed in locations along the lead comprising at least one of contiguous locations distal to the lead electrode, contiguous locations proximal to the lead electrode, and discontinuous locations in juxtaposition to the lead electrode.

112. An implantable subcutaneous cardioverter-defibrillator according to claim 108, further comprising:

at least one sensing electrode formed on and electrically insulated from the electrically conductive surface and internally electrically connected to the cardioversion-defibrillation circuitry, each sensing electrode interfacing with sensing circuitry within the cardioversion defibrillation circuitry and providing a sensing function.

113. An implantable subcutaneous cardioverter-defibrillator according to claim 108, further comprising:

an anti-arrhythmic pulse generator integral to the cardioversion-defibrillation circuitry and generating an anti-arrhythmia biphasic waveform to the electrically conductive surface with characteristics comprising at least one of a waveform generated from a capacitor having a capacitance between approximately 50 μ

F and 200 μ

F, a voltage between approximately 800 V and 2000 V, an energy between 40 J and 150 J, and a duration between approximately 5 msec to 25 msec.

114. An implantable subcutaneous cardioverter-defibrillator with discrete electrically active canister, comprising:

an implantable canister providing a housing enclosing and containing cardioversion-defibrillation circuitry externally interfaceable via an electrically isolated connector block on a proximal end of the housing, the housing defining a discrete electrically conductive surface on an outer surface and internally connecting electrically to the cardioversion-defibrillation circuitry, the housing further defining an electrically insulated surface juxtaposed to the discrete electrically conductive surface and substantially interposed therefrom by an electrically insulated area;

a substantially pliant and directable lead enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block, the lead being electrically inert; and

a lead electrode circumferentially formed on a distal end of the lead and electrically interfaced via the one or more conductors to the cardioversion-defibrillation circuitry to deliver an electrical therapy responsive to an autonomously detected arrhythmic condition without a transvenous, intracardiac or epicardial electrode.

115. An implantable subcutaneous cardioverter-defibrillator according to claim 114, further comprising:

at least one sensing electrode formed on at least one of the discrete electrically conductive surface and the electrically insulated surface, the at least one sensing electrode being electrically insulated from the discrete electrically conductive surface and internally electrically connected to the cardioversion-defibrillation circuitry, each sensing electrode interfacing with sensing circuitry within the cardioversion-defibrillation circuitry and providing a sensing function.

116. An implantable subcutaneous cardioverter-defibrillator providing antiarrhythmia therapy, comprising:

an implantable canister providing a housing enclosing and containing cardioversion-defibrillation circuitry externally interfaceable via an electrically isolated connector block on a proximal end of the housing, the housing defining an electrically conductive surface on an outer surface and internally connecting electrically to the cardioversion-defibrillation circuitry, the cardioversion-defibrillation circuitry monitoring cardiac physiological conditions;

a substantially pliant and directable lead enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block, the lead being electrically inert; and

a lead electrode circumferentially formed on a distal end of the lead and electrically interfaced via the one or more conductors to the cardioversion-defibrillation circuitry to deliver an anti-arrhythmic waveform responsive to an arrhythmic condition autonomously detected by the cardioversion-defibrillation circuitry without a transvenous, intracardiac or epicardial electrode.

117. An implantable subcutaneous cardioverter-defibrillator according to claim 116, wherein the anti-arrhythmia biphasic waveform has characteristics comprising at least one of a waveform generated from a capacitor having a capacitance between approximately 50 μ

F and 200 μ

F, a voltage between approximately 800 V and 2000 V, an energy between 40 J and 150 J, and a duration between approximately 5 msec to 25 msec.

118. An implantable subcutaneous cardioverter-defibrillator monitoring cardiac physiological conditions, comprising:

an implantable canister providing a housing enclosing and containing cardioversiondefibrillation circuitry externally interfaceable via an electrically isolated connector block on a proximal end of the housing, the housing defining an electrically conductive surface on an outer surface and internally connecting electrically to the cardioversion-defibrillation circuitry;

a substantially pliant and directable lead enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block, the lead being electrically inert; and

a sensing electrode circumferentially formed on a distal end of the lead and electrically interfaced via the one or more conductors to sensing circuitry within the cardioversion-defibrillation circuitry to deliver an electrical therapy responsive to an autonomously detected arrhythmic condition without a transvenous, intracardiac or epicardial electrode; and

monitoring circuitry integral to the cardioversion-defibrillation circuitry and deriving cardiac physiological measures relating to at least one of QRS signal morphology, QRS signal frequency content, QRS R-R interval stability data, and QRS amplitude characteristics.

119. An implantable subcutaneous cardioverter-defibrillator providing cardiac pacing, comprising:

an implantable canister providing a housing enclosing and containing cardioversion-defibrillation circuitry externally interfaceable via an electrically isolated connector block on a proximal end of the housing, the housing defining an electrically conductive surface on an outer surface and internally connecting electrically to the cardioversion-defibrillation circuitry;

a substantially pliant and directable lead enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block, the lead being electrically inert; and

a lead electrode circumferentially formed on a distal end of the lead and electrically interfaced via the one or more conductors to the cardioversion-defibrillation circuitry to deliver an electrical therapy responsive to an autonomously detected arrhythmic condition without a transvenous, intracardiac or epicardial electrode; and

pacing circuitry operatively conjunctive to the cardioversion-defibrillation circuitry which generates at least one of an anti-bradycardia and an anti-tachycardia pacing waveform via the electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry.

120. An implantable subcutaneous cardioverter-defibrillator inducing cardiac fibrillating episodes, comprising:

an implantable canister providing a housing enclosing and containing cardioversion-defibrillation circuitry externally interfaceable via an electrically isolated connector block on a proximal end of the housing, the housing defining an electrically conductive surface on an outer surface and internally connecting electrically to the cardioversion-defibrillation circuitry;

a substantially pliant and directable lead enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block, the lead being electrically inert; and

a lead electrode circumferentially formed on a distal end of the lead and electrically interfaced via the one or more conductors to the cardioversion-defibrillation circuitry to deliver an electrical therapy responsive to an autonomously detected arrhythmic condition without a transvenous, intracardiac or epicardial electrode; and

induction circuitry integral to the cardioversion-defibrillation circuitry which generates low amplitude voltage on a T-wave of an ECG via the electrically conductive surface and the lead electrode responsive to the cardioversion-defibrillation circuitry.

121. An implantable subcutaneous cardioverter-defibrillator detecting cardiopulmonary physiological conditions, comprising:

an implantable canister providing a housing enclosing and containing cardioversiondefibrillation circuitry externally interfaceable via an electrically isolated connector block on a proximal end of the housing, the housing defining an electrically conductive surface on an outer surface and internally connecting electrically to the cardioversion-defibrillation circuitry;

a substantially pliant and directable lead enclosing and guiding one or more conductors adaptably connected to the electrically isolated connector block, the lead being electrically inert; and

a sensing electrode circumferentially formed on a distal end of the lead and electrically interfaced via the one or more conductors to sensing circuitry within the cardioversion-defibrillation circuitry to deliver an electrical therapy responsive to an autonomously detected arrhythmic condition without a transvenous, intracardiac or epicardial electrode; and

detection circuitry integral to the cardioversion-defibrillation circuitry and deriving physiological measures relating to at least one of atrial fibrillation, ventricular fibrillation, transthoracic impedance, respiratory rate, heart rate, cardiac output, ECG shape and temperature.