Apparatus for detecting and treating ventricular arrhythmia

• US 20080140139A1
• Filed: 10/31/2007
• Published: 06/12/2008
• Est. Priority Date: 11/22/2000
• Status: Abandoned Application

• Current Assignee: Stephen D. Heinrich, Ward Brown
• Original Assignee: Stephen D. Heinrich, Ward Brown
• Inventors: Heinrich, Stephen D., Brown, Ward
• Application Number:
  US11/981,410
• Publication Number:
  US 20080140139A1
• Time in Patent Office: Days
• US Class Current: 607/4
• CPC Class Codes: A61N 1/0504 Subcutaneous electrodes
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3629 in combination with non-electric therapy
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• 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 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: A61N 1/39624 Pain reduction therapy
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock

Abstract

A system and method for long-term monitoring of cardiac conditions such as arrhythmias is disclosed. The invention includes a pulse generator including means for sensing an arrhythmia. The pulse generator is coupled to at least one subcutaneous electrode or electrode array for providing electrical stimulation such as cardioversion/defibrillation shocks and/or pacing pulses. The electrical stimulation may be provided between multiple subcutaneous electrodes, or between one or more such electrodes and the housing of the pulse generator. In one embodiment, the pulse generator includes one or more electrodes that are isolated from the can. These electrodes may be used to sense cardiac signals.

Claims

1. A system for providing arrhythmia therapy to a patient, comprising:

an implantable pulse generator;

a sensing circuit coupled to the implantable pulse generator; and

a subcutaneous electrode array coupled to the implantable pulse generator to deliver electrical stimulation to the patient upon detection by the sensing circuit of an arrhythmia

wherein the system does not comprise a transvenous, intracardiac, or epicardial electrode.

2. The system of claim 1, wherein the subcutaneous electrode array is a defibrillation electrode array to deliver relatively high-voltage electrical stimulation to the patient.

3. The system of claim 1, wherein the sensing circuit includes a circuit to sense a bradyarrhythmia event, and wherein the subcutaneous electrode array is configured to deliver at least one pacing pulse to the patient upon detection of the bradyarrhythmia event.

4. The system of claim 1, wherein the system is housed within a can, and wherein the sensing circuit includes at least two sensing electrodes on at least a first surface of the can to sense cardiac signals.

5. The system of claim 2, wherein the system is housed within a can, and wherein the sensing circuit utilizes the defibrillation electrode array and the can to sense for an arrhythmia.

6. The system of claim 1, wherein the can includes at least one surface to deliver high-voltage shocks.

7. The system of claim 4, wherein the can includes at least one surface to deliver high-voltage shocks, and wherein the surface to deliver high-voltage shocks is different from the at least first surface of the can.

8. A method for treating patient arrhythmias, with a system that does not comprise a transvenous, intracardiac, or epicardial electrode, the method comprising:

providing a subcutaneous pulse generator;

providing a monitoring circuit to monitor the patient'"'"'s cardiac signals for arrhythmias; and

providing a subcutaneous electrode array to deliver electrical therapy to a patient.

9. A method of using a subcutaneously-placed pulse generator that is not coupled to a transvenous, intracardiac, or epicardial electrode to treat arrhythmias, the method comprising:

detecting an arrhythmia; and

employing at least one subcutaneous electrode to deliver therapy based on the detected arrhythmia.

10. The method of claim 9, wherein the detected arrhythmia is a tachyarrythmia, wherein the at least one subcutaneous electrode includes a defibrillation electrode, and wherein the therapy that is delivered is a relatively high-voltage shock.

11. The method of claim 9, wherein the detected arrhythmia is a bradyarrythmia, and wherein employing at least one subcutaneous electrode to deliver therapy based on the detected arrhythmia comprises delivering a pacing pulse in response to the detected bradyarrythmia.

12. A system for delivering electrical energy to the heart of a patient, the system comprising:

a subcutaneous pulse generator;

at least one sensing electrode disposed on a surface of the pulse generator and positioned proximate to subcutaneous tissue; and

at least one electrode array coupled to the pulse generator and positioned subcutaneously on the patients

wherein the system does not comprise a transvenous, intracardiac, or epicardial electrode.

13. An apparatus for monitoring cardiac signals of a patient, comprising;

a hermetically-sealed housing;

sensing means included within the housing; and

first and second electrode sets coupled to the sensing means, the first electrode set including at least one electrode adjacent to a surface of the housing positionable proximate subcutaneous tissue at a first location in the patient'"'"'s body, and the second electrode set coupled to a connector on the housing and forming an electrode array subcutaneously positionable in the patient'"'"'s body at a location different from the first locations

wherein the first and second electrode sets do not comprise a transvenous, intracardiac, or epicardial electrode.

14. A method of implanting a subcutaneous cardioverter-defibrillator in a patient for treating arrhythmias without a transvenous, intracardiac or epicardial electrode, comprising:

making a skin incision in the patient'"'"'s body;

implanting an electrode subcutaneously in the patient; and

placing an electrically active canister subcutaneously in 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.

55. The method of claim 14, wherein the electrode can be subcutaneously implanted at various locations in the body.

56. The method of claim 14, wherein the canister can be subcutaneously implanted at various locations in the body.

15. A method for providing anti-arrhythmia therapy via a subcutaneous cardioverter-defibrillator and without a transvenous, intracardiac or epicardial electrode, comprising:

implanting a canister comprising a biocompatible housing subcutaneously in a patient, 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, 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.

16. 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.

57. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the operational circuitry comprises an impedance detection means for measuring impedance.

58. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the operational circuitry can measure cardiac output.

61. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the electrical cardioversion-defibrillating energy is equal to the energy required to terminate the potentially fatal heart rhythm.

62. The subcutaneous implantable cardioverter-defibrillator of claim 16, 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.

63. The subcutaneous implantable cardioverter-defibrillator of claim 62, wherein the first sensing electrode, the second sensing electrode, and the cardioversion-defibrillation electrode are located near each other.

64. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the operational circuitry is programmable.

65. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the operational circuitry can detect tachycardia.

66. The subcutaneous implantable cardioverter-defibrillator of claim 65, further comprising means for delivering antitachycardia pacing when the operational circuitry senses a tachycardia rhythm.

67. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the operational circuitry can detect tachycardia and fibrillation.

68. The subcutaneous implantable cardioverter-defibrillator of claim 67, wherein the operational circuitry can deliver defibrillation energy to treat the detected fibrillation.

69. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the electrical cardioversion-defibrillating energy is delivered in a biphasic waveform.

70. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the capacitor has a capacitance equal to the capacitance required to terminate the potentially fatal heart rhythm.

71. The subcutaneous implantable cardioverter-defibrillator of claim 16, wherein the canister is provided with at least one sensing electrode.

72. The subcutaneous implantable cardioverter-defibrillator of claim 16, 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.

73. The subcutaneous implantable cardioverter-defibrillator of claim 16, 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.

74. The subcutaneous implantable cardioverter-defibrillator of claim 16, 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.

75. The cardioverter-defibrillator according to claim 16, wherein the canister is any shape suitable for subcutaneous implantation.

17. 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 connected to the canister 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.

59. A cardioverter-defibrillator according to claim 17, further comprising:

at least one further electrically inert lead comprising a substantially pliant and directable cannula connected 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.

60. A cardioverter-defibrillator according to claim 17, 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 via the sensing electrodes.

76. A cardioverter-defibrillator according to claim 17, 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.

77. A cardioverter-defibrillator according to claim 17, 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.

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

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

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

a 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.

80. A cardioverter-defibrillator according to claim 17, further comprising:

monitoring circuitry integral to the cardioversion-defibrillation circuitry and deriving physiological measures.

81. A cardioverter-defibrillator according to claim 17, 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.

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

the pulse generator generating the anti-arrhythmia waveform as a biphasic waveform.

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

the cardioversion-defibrillation circuitry initiating the anti-arrhythmia therapy upon detection of a certain event.

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

the cardioversion-defibrillation circuitry terminating the anti-arrhythmia therapy upon detection of a certain event.

85. A cardioverter-defibrillator according to claim 17, wherein the housing is any shape suitable for implantation.

86. A cardioverter-defibrillator according to claim 17, further comprising:

the lead electrode formed non-circumferentially on the electrically inert lead.

87. A cardioverter-defibrillator according to claim 17, further comprising:

at least one sensing electrode formed on the electrically inert lead.

88. A cardioverter-defibrillator according to claim 87, wherein the at least one sensing electrode is formed distal to the lead electrode.

89. A cardioverter-defibrillator according to claim 87, wherein the at least one sensing electrode is formed near the lead electrode.

90. A cardioverter-defibrillator according to claim 87, wherein the at least one sensing electrode is formed non-circumferentially on the electrically inert lead.

91. A cardioverter-defibrillator according to claim 17, further comprising:

at least one further electrically inert lead comprising a substantially pliant and directable cannula connected 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.

18. 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.

92. A subcutaneous cardioverter-defibrillator according to claim 18, further comprising:

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

93. A subcutaneous cardioverter-defibrillator according to claim 18, further comprising:

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

94. A subcutaneous cardioverter-defibrillator according to claim 18, 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.

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

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

96. A subcutaneous cardioverter-defibrillator according to claim 18, 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.

97. A subcutaneous cardioverter-defibrillator according to claim 96, 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.

98. A subcutaneous cardioverter-defibrillator according to claim 18, further comprising:

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

99. A subcutaneous cardioverter-defibrillator according to claim 98, wherein the at least one sensing electrode is formed near the lead electrode.

100. A subcutaneous cardioverter-defibrillator according to claim 98, wherein the at least one sensing electrode is formed non-circumferentially on the electrically inert lead.

101. The cardioverter-defibrillator according to claim 18, wherein the housing is any shape suitable for implantation.

102. A subcutaneous cardioverter-defibrillator according to claim 18, 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.

103. A subcutaneous cardioverter-defibrillator according to claim 18, further comprising:

a pulse generator integral to the cardioversion-defibrillation circuitry and generating an anti-arrhythmia biphasic waveform.

104. A subcutaneous cardioverter-defibrillator according to claim 18, further comprising:

the cardioversion-defibrillation circuitry comprising at least one of;

monitoring circuitry deriving physiological measures;

and 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.

19. 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.

105. A cardioversion-defibrillation device according to claim 19, further comprising:

means for monitoring and deriving physiological measures; and

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.

106. A cardioversion-defibrillation device according to claim 19, 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.

107. A cardioversion-defibrillation device according to claim 19, 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.

108. A cardioversion-defibrillation device according to claim 19, 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.

109. A subcutaneous cardioverter-defibrillator according to claim 19, further comprising:

sensing means formed near the electrical therapy delivering means.

110. A cardioversion-defibrillation device according to claim 19, 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.

111. A cardioversion-defibrillation device according to claim 19, further comprising:

pulse generating means integral to the cardioversion-defibrillation circuitry and generating an anti-arrhythmia biphasic waveform.

112. A cardioversion-defibrillation device according to claim 19, wherein the housing means is any shape suitable for implantation.

20. 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.

113. An implantable subcutaneous cardioverter-defibrillator according to claim 20, further comprising:

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

114. An implantable subcutaneous cardioverter-defibrillator according to claim 20, further comprising:

at least one sensing electrode circumferentially formed on the lead and electrically connected with the one or more conductors via the isolated connector block to the cardioversion-defibrillation circuitry, the at least one sensing electrode interfacing with sensing circuitry within the cardioversion-defibrillation circuitry and providing a sensing function.

115. An implantable subcutaneous cardioverter-defibrillator according to claim 114, wherein the at least one sensing electrode is formed near the lead electrode.

116. An implantable subcutaneous cardioverter-defibrillator according to claim 20, 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, the at least one sensing electrode interfacing with sensing circuitry within the cardioversion defibrillation circuitry and providing a sensing function.

117. An implantable subcutaneous cardioverter-defibrillator according to claim 20, further comprising:

an anti-arrhythmic pulse generator integral to the cardioversion-defibrillation circuitry and generating an anti-arrhythmia biphasic waveform to the electrically conductive.

21. 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.

120. An implantable subcutaneous cardioverter-defibrillator according to claim 21, wherein the anti-arrhythmia waveform is a biphasic waveform.

22. An implantable subcutaneous cardioverter-defibrillator monitoring cardiac physiological conditions, 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;

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.

23. An implantable subcutaneous cardioverter-defibrillator detecting cardiopulmonary physiological conditions, 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;

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.

24. A subcutaneous implantable cardioverter-defibrillator comprising:

a housing including a source of electrical energy, a capacitor, and operational circuitry that senses the presence of potential fatal heart rhythms;

at least one cardioversion/defibrillation electrode located on the housing;

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.

25. The subcutaneous implantable cardioverter-defibrillator of claim 24, wherein the electrical cardioversion-defibrillating energy is equal to the energy required to terminate the potentially fatal heart rhythm.

26. The subcutaneous implantable cardioverter-defibrillator of claim 24, further comprising at least two sensing electrodes located on the housing.

27. The subcutaneous implantable cardioverter-defibrillator of claim 26, wherein the sensing electrodes are spaced apart from each other.

28. The subcutaneous implantable cardioverter-defibrillator of claim 24, wherein the operational circuitry is programmable.

29. The subcutaneous implantable cardioverter-defibrillator of claim 24, wherein the operational circuitry can detect tachycardia.

30. The subcutaneous implantable cardioverter-defibrillator of claim 29, further comprising means for delivering antitachycardia therapy when the operational circuitry senses a tachycardia rhythm.

31. The subcutaneous implantable cardioverter-defibrillator of claim 24, wherein the operational circuitry can detect tachycardia and fibrillation.

32. The subcutaneous implantable cardioverter-defibrillator of claim 31, wherein the operational circuitry can deliver defibrillation energy to treat the detected fibrillation.

33. The subcutaneous implantable cardioverter-defibrillator of claim 24, wherein the electrical cardioversion-defibrillating energy is delivered in a biphasic wave form.

34. The subcutaneous implantable cardioverter-defibrillator of claim 24, wherein the capacitance is the capacitance required to terminate the potentially fatal heart rhythm.

35. The subcutaneous implantable cardioverter-defibrillator of claim 24, wherein the housing is provided with at least one sensing electrode.

36. The subcutaneous implantable cardioverter-defibrillator of claim 24, wherein the housing is provided with one or more sensing electrodes, and wherein said cardioverter-defibrillator is further provided with a subcutaneous electrode with one or more sensing electrodes, and means for selecting two sensing electrodes from the sensing electrodes located on the housing and the sensing electrode located on the subcutaneous electrode that provide adequate QRS wave detection.

37. A method of implanting an implantable subcutaneous cardioverter-defibrillator in a patient comprising:

making a skin incision in the patient'"'"'s body;

implanting a subcutaneous cardioverter-defibrillator, the subcutaneous cardioverter-defibrillator including a housing enclosing and containing cardioversion-defibrillation circuitry and defining at least one electrode electrically interfaced to the cardioversion-defibrillation circuitry to deliver an electrical therapy to the heart of a patient without a transvenous, intracardiac or epicardial electrode; and

closing the skin incision.

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

a canister comprising a biocompatible housing enclosing and containing cardioversion-defibrillation circuitry;

at least one electrode formed on the biocompatible housing and electrically interfaced to the cardioversion-defibrillation circuitry to deliver an electrical therapy to the heart of a patient; and

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

39. The cardioverter-defibrillator according to claim 38, further comprising:

at least one sensing electrode formed on, and electrically insulated from, the biocompatible housing and electrically interfaced to the cardioversion-defibrillation circuitry.

40. The cardioverter-defibrillator according to claim 38, further comprising:

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

41. The cardioverter-defibrillator according to claim 40, further comprising:

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

42. The cardioverter-defibrillator according to claim 40, further comprising:

an insulated margin around the at least one electrode along the at least one electrically insulated surface and defining a concentrated electrically conductive surface.

43. The cardioverter-defibrillator according to claim 38, further comprising:

monitoring circuitry integral to the cardioversion-defibrillation circuitry and deriving physiological measures.

44. The cardioverter-defibrillator according to claim 38, 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 electrode responsive to the cardioversion-defibrillation circuitry.

45. The cardioverter-defibrillator according to claim 44, further comprising:

the pulse generator generating the anti-arrhythmia waveform as a biphasic waveform.

46. The cardioverter-defibrillator according to claim 45, further comprising:

the cardioversion-defibrillation circuitry initiating the anti-arrhythmia therapy upon detection of a certain event.

47. The cardioverter-defibrillator according to claim 45, further comprising:

the cardioversion-defibrillation circuitry terminating the anti-arrhythmia therapy upon detection of a certain event.

48. The cardioverter-defibrillator according to claim 45, further comprising:

power supply components integral to the cardioversion-defibrillation circuitry for providing power sufficient to generate the anti-arrhythmia waveform.

49. The cardioverter-defibrillator according to claim 38, wherein the housing is any shape suitable for implantation.

50. The cardioverter-defibrillator according to claim 38, wherein the at least one electrode interfaces with high voltage and low impedance circuitry.

51. The cardioverter-defibrillator according to claim 50, further comprising:

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

52. The cardioverter-defibrillator according to claim 38, wherein the at least one electrode faces the heart when implanted.

53. A method for providing anti-arrhythmia therapy via a subcutaneous cardioverter-defibrillator and without a transvenous, intracardiac or epicardial electrode, comprising:

implanting a canister comprising a biocompatible housing subcutaneously in a patient, the biocompatible housing enclosing and containing cardioversion-defibrillation circuitry and defining at least one electrode on the outer surface of the biocompatible housing that faces the heart and electrically connected to the cardioversion-defibrillation circuitry; and

delivering an electrical therapy comprising an anti-arrhythmia waveform to the heart of a patient from the at least one electrode.

54. The method according to claim 53, the method further comprising:

providing a plurality of sensing electrodes formed on the canister, electrically isolated from the at least one electrode, each sensing electrode interfacing with sensing circuitry to the cardioversion-defibrillation circuitry; and

monitoring and deriving cardiac physiological measures via the sensing electrodes.

118. 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.

119. An implantable subcutaneous cardioverter-defibrillator according to claim 118, 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.