US5782879A — Apparatus and method for discriminating flow of b…

Claim 1

Independent Claim 236 words

An implantable cardiac stimulator, comprising: a first implantable electrode configured for implanting in a blood flow path of the cardiovascular system of a body; a second implantable electrode configured for implanting in the body such that an ionically conductive path exists through the body between the first and second electrodes; a reference implantable electrode configured for implanting in the body such that an ionically conductive path exists through the body between the first and reference electrodes; means for detecting cardiac fibrillation, whereby, if fibrillation is detected, a state of substantially no flow of blood at said first electrode can be assumed: means in electrical communication with said first and second electrodes for delivering a reference shock between said first and second electrodes at a time when there is substantially no flow of blood at said first electrode, and for subsequently delivering a defibrillation shock between said first and second electrodes; means for sensing in the time domain a reference electrical potential between said first electrode and said reference electrode following delivery of said reference shock, and for sensing in the time domain a test electrical potential between said first electrode and said reference electrode following delivery of said defibrillation shock; and means for analyzing and comparing said sensed reference electrical potential and said sensed test electrical potential, and for determining on the basis of said comparison whether blood is flowing following delivery of said defibrillation shock.

Claim 2

Dependent Claim 236 words

An implantable cardiac stimulator, comprising: a first implantable electrode configured for implanting in a blood flow path of the cardiovascular system of a body; a second implantable electrode configured for implanting in the body such that an ionically conductive path exists through the body between the first and second electrodes; a reference implantable electrode configured for implanting in the body such that an ionically conductive path exists through the body between the first and reference electrodes; means for detecting cardiac fibrillation, whereby, if fibrillation is detected, a state of substantially no flow of blood at said first electrode can be assumed: means in electrical communication with said first and second electrodes for delivering a reference shock between said first and second electrodes at a time when there is substantially no flow of blood at said first electrode, and for subsequently delivering a defibrillation shock between said first and second electrodes; means for sensing in the time domain a reference electrical potential between said first electrode and said reference electrode following delivery of said reference shock, and for sensing in the time domain a test electrical potential between said first electrode and said reference electrode following delivery of said defibrillation shock; and means for analyzing and comparing said sensed reference electrical potential and said sensed test electrical potential, and for determining on the basis of said comparison whether blood is flowing following delivery of said defibrillation shock.

Claim 3

Dependent Claim 23 words

The implantable cardiac stimulator of claim 1, in which said second electrode and said reference electrode are electrically common at a common locus.

Claim 4

Dependent Claim 22 words

The implantable cardiac stimulator of claim 1, in which said second electrode and said reference electrode are electrically non-common at separate loci.

Claim 5

Dependent Claim 32 words

The implantable cardiac stimulator of claim 1, in which said means for analyzing and comparing includes means for performing a regression analysis of each of said sensed reference and test electrical potentials.

Claim 6

Dependent Claim 68 words

The implantable cardiac stimulator of claim 4, in which said regression analysis includes determining a damping constant, α, where the sensed reference and test electrical potentials are expressed as a function of time by the equation f(t)=Ae.sup.±αt, in which A is a constant, e is the base of the natural logarithm, and t is time, and comparing the damping constants of said sensed reference and test electrical potentials.

Claim 7

Dependent Claim 56 words

The implantable cardiac stimulator of claim 4, in which said regression analysis includes determining a coefficient, a, where the sensed reference and test electrical potentials are expressed as a function of time by the equation ##EQU1## representing a general polynomial fit of degree n, and comparing the coefficients of said sensed reference and test electrical potentials.

Claim 8

Dependent Claim 77 words

The implantable cardiac stimulator of claim 1, in which said means for analyzing and comparing includes means for performing differentiation of the sensed reference and test electrical potentials, and, given that the first derivative of the sensed reference and test electrical potential is expressed as a function of time by the equation f'(t)=∂V/∂t, in which V is the sensed electrical potential and t is time, comparing the values of f'(t) for said reference and test electrical potentials.

Claim 9

Dependent Claim 81 words

The implantable cardiac stimulator of claim 1, in which said means for analyzing and comparing includes means for performing differentiation of the sensed reference and test electrical potentials, and, given that the second derivative of the sensed reference and test electrical potentials are expressed as a function of time by the equation f"(t)=∂ 2 V/∂t 2 , in which V is the sensed electrical potential and t is time, comparing the values of f"(t) for said reference and test electrical potentials.

Claim 10

Dependent Claim 53 words

The implantable cardiac stimulator of claim 1, in which said means for analyzing and comparing includes signal processing means for processing said sensed reference and test electrical potentials to generate the first derivative of each of said potentials, and comparing the values of the first derivative for said reference and test electrical potentials.

Claim 11

Dependent Claim 53 words

The implantable cardiac stimulator of claim 1, in which said means for analyzing and comparing includes signal processing means for processing said sensed reference and test electrical potentials to generate the second derivative of each of said potentials, and comparing the values of the second derivative for said reference and test electrical potentials.

Claim 12

Independent Claim 194 words

A method for discriminating cardiovascular blood flow, comprising the steps of: implanting a first electrode in a blood flow path of the cardiovascular system; implanting a second electrode such that an ionically conductive path exists between said first and second electrodes; implanting a reference electrode such that an ionically conductive path exists between said first and reference electrodes; detecting cardiac fibrillation, whereby, if fibrillation is detected, a state of substantially no flow of blood at said first electrode can be assumed; delivering a reference electrical shock between said first and second electrodes at a time when there is substantially no flow of blood at said first electrode; subsequently delivering a defibrillating electrical shock between said first and second electrodes; sensing in the time domain a reference electrical potential between said first and reference electrodes following delivery of said reference electrical shock; sensing in the time domain a test electrical potential between said first and reference electrodes following delivery of said defibrillation electrical shock; analyzing and comparing said test electrical potential to said reference electrical potential, and determining, on the basis of said comparison, whether blood is flowing following delivery of said defibrillation electrical shock.

Claim 13

Independent Claim 194 words

A method for discriminating cardiovascular blood flow, comprising the steps of: implanting a first electrode in a blood flow path of the cardiovascular system; implanting a second electrode such that an ionically conductive path exists between said first and second electrodes; implanting a reference electrode such that an ionically conductive path exists between said first and reference electrodes; detecting cardiac fibrillation, whereby, if fibrillation is detected, a state of substantially no flow of blood at said first electrode can be assumed; delivering a reference electrical shock between said first and second electrodes at a time when there is substantially no flow of blood at said first electrode; subsequently delivering a defibrillating electrical shock between said first and second electrodes; sensing in the time domain a reference electrical potential between said first and reference electrodes following delivery of said reference electrical shock; sensing in the time domain a test electrical potential between said first and reference electrodes following delivery of said defibrillation electrical shock; analyzing and comparing said test electrical potential to said reference electrical potential, and determining, on the basis of said comparison, whether blood is flowing following delivery of said defibrillation electrical shock.

Claim 14

Dependent Claim 39 words

The method of claim 11, in which said step of implanting a second electrode and said step of implanting a reference electrode are performed commonly by implanting a common component comprising both said second electrode and said reference electrode.

Claim 15

Dependent Claim 36 words

The method of claim 11, in which said step of implanting a second electrode and said step of implanting a reference electrode are performed independently by implanting separate components comprising said second and reference electrodes, respectively.

Claim 16

Dependent Claim 28 words

The method of claim 11, in which said step of analyzing and comparing includes performing a regression analysis of each of said sensed reference and test electrical potentials.

Claim 17

Dependent Claim 66 words

The method of claim 14, in which said regression analysis includes determining a damping constant, α, where the sensed reference and test electrical potentials are expressed as a function of time by the equation f(t)=Ae.sup.±αt, in which A is a constant, e is the base of the natural logarithm, and t is time, and comparing the damping constants of said sensed reference and test electrical potentials.

Claim 18

Dependent Claim 66 words

The method of claim 14, in which said regression analysis includes determining a coefficient, a, where the sensed reference and test electrical potentials are expressed as a function of time by the equation f(t)=Σ j=0 n a j t j , in which t is time, representing a general polynomial fit of degree n, and comparing the coefficients of said sensed reference and test electrical potentials.

Claim 19

Dependent Claim 73 words

The method of claim 11, in which said step of analyzing and comparing includes performing differentiation of the sensed reference and test electrical potentials, and, given that the first derivative of the sensed reference and test electrical potentials are expressed as a function of time by the equation f'(t)=∂V/∂t, in which V is the sensed electrical potential and t is time, comparing the values of f'(t) for said reference and test electrical potentials.

Claim 20

Dependent Claim 76 words

The method of claim 11, in which said step of analyzing and comparing includes performing differentiation of the sensed reference and test electrical potentials, and, given that the second derivative of the sensed reference and test electrical potentials are expressed as a function of time by the equation f"(t)=∂ 2 V/∂t 2 in which V is the sensed electrical potentia and t is time, comparing the values of f"(t) for said reference and test electrical potentials.

Claim 21

Dependent Claim 49 words

The method of claim 11, in which said step of analyzing and comparing includes signal processing of said sensed reference and test electrical potentials to generate the first derivative of each of said potentials, and comparing the values of the first derivative for said reference and test electrical potentials.

Claim 22

Dependent Claim 49 words

The method of claim 11, in which said step of analyzing and comparing includes signal processing of said sensed reference and test electrical potentials to generate the second derivative of each of said potentials, and comparing the values of the second derivative for said reference and test electrical potentials.

Claim 23

Independent Claim 218 words

A method of discriminating flow of blood in a cardiovascular system of a body, comprising the steps of: disposing a first electrode in a blood flow path of the cardiovascular system; disposing a second electrode such that an ionically conductive path exists through the body between said first electrode in a blood flow path and said second electrode, imposing an electrical potential on said first electrode by connecting a voltage source between said first electrode in the blood flow path and said second electrode; disconnecting said voltage source from said first electrode after said electrical potential has been imposed; allowing the electrical potential on said first electrode to discharge at least partially; sensing the discharging electrical potential in the time domain following said step of imposing an electrical potential by disposing a reference electrode such that an ionically conductive path exists through the body between said first electrode in a blood flow path and said reference electrode, and sensing the potential of the electrode in a blood flow path relative to the potential of said reference electrode; and analyzing said sensed electrical potential to discriminate flow of blood, wherein said step of disposing a second electrode and said step of disposing a reference electrode are performed independently by implanting separate components comprising said second and reference electrodes, respectively.

Claim 24

Independent Claim 218 words

A method of discriminating flow of blood in a cardiovascular system of a body, comprising the steps of: disposing a first electrode in a blood flow path of the cardiovascular system; disposing a second electrode such that an ionically conductive path exists through the body between said first electrode in a blood flow path and said second electrode, imposing an electrical potential on said first electrode by connecting a voltage source between said first electrode in the blood flow path and said second electrode; disconnecting said voltage source from said first electrode after said electrical potential has been imposed; allowing the electrical potential on said first electrode to discharge at least partially; sensing the discharging electrical potential in the time domain following said step of imposing an electrical potential by disposing a reference electrode such that an ionically conductive path exists through the body between said first electrode in a blood flow path and said reference electrode, and sensing the potential of the electrode in a blood flow path relative to the potential of said reference electrode; and analyzing said sensed electrical potential to discriminate flow of blood, wherein said step of disposing a second electrode and said step of disposing a reference electrode are performed independently by implanting separate components comprising said second and reference electrodes, respectively.

Claim 25

Independent Claim 253 words

An apparatus for discriminating flow of blood in a cardiovascular system, comprising: a first implantable electrode configured for implanting in a blood flow path of the cardiovascular system; a second implantable electrode configured for implanting in the body such that an ionically conductive path exists through the body between the first and second electrodes; a reference implantable electrode configured for implanting in the body such that an ionically conductive path exists through the body between the first and reference electrodes in which said second electrode and said reference electrode are electrically non-common at separate locii; means for sensing cardiac parameters from which the state of flow of blood at said first electrode can be deduced; means in electrical communication with said first and second electrodes for delivering a reference shock between said first and second electrodes at a time when the state of flow of blood at said first electrode is known, and for subsequently delivering a test shock between said first and second electrodes; means for sensing in the time domain a reference electrical potential between said first electrode and said reference electrode following delivery of said reference shock, and for sensing in the time domain a test electrical potential between said first electrode and said reference electrode following delivery of said test shock; and means for analyzing and comparing said sensed reference electrical potential and said sensed test electrical potential., and for determining on the basis of said comparison the state of flow of blood following delivery of said test shock.

Claim 26

Independent Claim 253 words

An apparatus for discriminating flow of blood in a cardiovascular system, comprising: a first implantable electrode configured for implanting in a blood flow path of the cardiovascular system; a second implantable electrode configured for implanting in the body such that an ionically conductive path exists through the body between the first and second electrodes; a reference implantable electrode configured for implanting in the body such that an ionically conductive path exists through the body between the first and reference electrodes in which said second electrode and said reference electrode are electrically non-common at separate locii; means for sensing cardiac parameters from which the state of flow of blood at said first electrode can be deduced; means in electrical communication with said first and second electrodes for delivering a reference shock between said first and second electrodes at a time when the state of flow of blood at said first electrode is known, and for subsequently delivering a test shock between said first and second electrodes; means for sensing in the time domain a reference electrical potential between said first electrode and said reference electrode following delivery of said reference shock, and for sensing in the time domain a test electrical potential between said first electrode and said reference electrode following delivery of said test shock; and means for analyzing and comparing said sensed reference electrical potential and said sensed test electrical potential., and for determining on the basis of said comparison the state of flow of blood following delivery of said test shock.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-07-20	2002-01-19	2002-07-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-07-20	2006-01-19	2006-07-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-07-20	2010-01-19	2010-07-21	$7700.00	Window Closed / Lapsed

Apparatus and method for discriminating flow of blood in a cardiovascular system

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