US5058583A — Multiple monopolar system and method of measuring…

Claim 1

Independent Claim 81 words

A multiple monopolar system for measuring the stroke volume of a patient's heart, comprising: an intracardiac impedance catheter having a distal end and a proximal end; a plurality of same-polarity-monopolar electrodes axially spaced along the surface of said distal end of said impedance catheter; a reference electrode adapted for positioning distant from said monopolar electrodes in the patient's body; and monopolar means for supplying a drive signal and measuring impedance between each of said monopolar electrodes and said distant reference electrode.

Claim 2

Dependent Claim 81 words

A multiple monopolar system for measuring the stroke volume of a patient's heart, comprising: an intracardiac impedance catheter having a distal end and a proximal end; a plurality of same-polarity-monopolar electrodes axially spaced along the surface of said distal end of said impedance catheter; a reference electrode adapted for positioning distant from said monopolar electrodes in the patient's body; and monopolar means for supplying a drive signal and measuring impedance between each of said monopolar electrodes and said distant reference electrode.

Claim 3

Dependent Claim 230 words

A multiple monopolar system for measuring the stroke volume of a patient's heart, comprising: an intracardiac impedance catheter having a distal end and a proximal end; a plurality of monopolar electrodes axially spaced along the surface of said distal end of said impedance catheter; a reference electrode adapted for positioning distant from said monopolar electrodes in the patient's body; monopolar means for supplying a drive signal and measuring impedance between each of said monopolar electrodes and said distant reference electrode; an implantable cardiac device having a conductive case which incorporates said reference electrode, said cardiac device including a pulse generator housed within said case, said case being attached to said proximal end of said catheter; a stimulating electrode disposed on said distal end of said catheter distal to said monopolar electrodes; a first electrical conductor connected to said stimulating electrode and extending therefrom within said catheter to said proximal end thereof; means for electrically connecting said pulse generator to said first electrical conductor; and a plurality of individual electrical conductors connected to respective ones of said monopolar electrodes and extending therefrom within said catheter to said proximal end thereof; wherein said monopolar means further includes a current source and an impedance processor housed within said case, and means for electrically connecting an output of said current source and an input of said impedance processor to each of said individual conductors.

Claim 4

Dependent Claim 230 words

A multiple monopolar system for measuring the stroke volume of a patient's heart, comprising: an intracardiac impedance catheter having a distal end and a proximal end; a plurality of monopolar electrodes axially spaced along the surface of said distal end of said impedance catheter; a reference electrode adapted for positioning distant from said monopolar electrodes in the patient's body; monopolar means for supplying a drive signal and measuring impedance between each of said monopolar electrodes and said distant reference electrode; an implantable cardiac device having a conductive case which incorporates said reference electrode, said cardiac device including a pulse generator housed within said case, said case being attached to said proximal end of said catheter; a stimulating electrode disposed on said distal end of said catheter distal to said monopolar electrodes; a first electrical conductor connected to said stimulating electrode and extending therefrom within said catheter to said proximal end thereof; means for electrically connecting said pulse generator to said first electrical conductor; and a plurality of individual electrical conductors connected to respective ones of said monopolar electrodes and extending therefrom within said catheter to said proximal end thereof; wherein said monopolar means further includes a current source and an impedance processor housed within said case, and means for electrically connecting an output of said current source and an input of said impedance processor to each of said individual conductors.

Claim 5

Dependent Claim 34 words

The multiple monopolar system of claim 2 wherein said monopolar means further includes means for selecting the monopolar electrode whose output is determined to be most representative of stroke volume for a particular patient.

Claim 6

Dependent Claim 54 words

The multiple monopolar system of claim 2 wherein said monopolar means further includes means for switching said current source and said impedance processor sequentially between selected ones of said individual conductors; and wherein said impedance processor includes means for obtaining a weighted sum of signals appearing on said individual conductors from said monopolar electrodes.

Claim 7

Dependent Claim 28 words

The multiple monopolar system of claim 2 wherein said monopolar means further includes means for connecting said current source and said impedance processor simultaneously to said individual conductors.

Claim 8

Dependent Claim 46 words

The multiple monopolar system of claim 5 wherein said current source includes means for driving said individual conductors at different frequencies, and wherein said impedance processor includes means for discriminating on the basis of frequency between signals appearing on said individual conductors from said monopolar electrodes.

Claim 9

Dependent Claim 79 words

A multiple monopolar method of measuring the stroke volume of a patient's heart, comprising the steps of: introducing into the patient's heart an impedance catheter having a plurality of same-polarity-monopolar electrodes axially spaced along the surface of one end; positioning a reference electrode distant from said monopolar electrodes in the patient's body; and supplying a drive signal and measuring impedance between each of said monopolar electrodes and said distant reference electrode for measuring the stroke volume of said heart.

Claim 10

Dependent Claim 79 words

A multiple monopolar method of measuring the stroke volume of a patient's heart, comprising the steps of: introducing into the patient's heart an impedance catheter having a plurality of same-polarity-monopolar electrodes axially spaced along the surface of one end; positioning a reference electrode distant from said monopolar electrodes in the patient's body; and supplying a drive signal and measuring impedance between each of said monopolar electrodes and said distant reference electrode for measuring the stroke volume of said heart.

Claim 11

Dependent Claim 211 words

A multiple monopolar method of measuring the stroke volume of a patient's heart, comprising the steps of: introducing into the patient's heart an impedance catheter having a plurality of monopolar electrodes axially spaced along the surface of one end; positioning a reference electrode distant from said monopolar electrodes in the patient's body; supplying a drive signal and measuring impedance between each of said monopolar electrodes and said distant reference electrode; wherein said supplying step is performed with a current source and an impedance processor housed within a case of an implantable cardiac device, said cardiac device including a pulse generator housed within said case, said case being attached to said proximal end of said catheter; wherein said catheter includes a stimulating electrode disposed on said distal end thereof distal to said monopolar electrodes, and an electrical conductor connected to said stimulating electrode and extending therefrom within said catheter to said proximal end thereof; and wherein said supplying step further includes electrically connecting an output of said current source and an input of said impedance processor to each of a plurality of individual electrical conductors connected to respective ones of said monopolar electrodes and extending therefrom within said catheter to said proximal end thereof for measuring the stroke volume of said heart.

Claim 12

Dependent Claim 211 words

A multiple monopolar method of measuring the stroke volume of a patient's heart, comprising the steps of: introducing into the patient's heart an impedance catheter having a plurality of monopolar electrodes axially spaced along the surface of one end; positioning a reference electrode distant from said monopolar electrodes in the patient's body; supplying a drive signal and measuring impedance between each of said monopolar electrodes and said distant reference electrode; wherein said supplying step is performed with a current source and an impedance processor housed within a case of an implantable cardiac device, said cardiac device including a pulse generator housed within said case, said case being attached to said proximal end of said catheter; wherein said catheter includes a stimulating electrode disposed on said distal end thereof distal to said monopolar electrodes, and an electrical conductor connected to said stimulating electrode and extending therefrom within said catheter to said proximal end thereof; and wherein said supplying step further includes electrically connecting an output of said current source and an input of said impedance processor to each of a plurality of individual electrical conductors connected to respective ones of said monopolar electrodes and extending therefrom within said catheter to said proximal end thereof for measuring the stroke volume of said heart.

Claim 13

Dependent Claim 31 words

A multiple monopolar method of claim 8, further comprising the step of selecting the monopolar electrode whose output is determined to be most representative of stroke volume for a particular patient.

Claim 14

Dependent Claim 44 words

The multiple monopolar method of claim 8, further comprising the steps of: switching said current source and said impedance processor sequentially between selected ones of said individual conductors; and obtaining a weighted sum of signals appearing on said individual conductors from said monopolar electrodes.

Claim 15

Dependent Claim 25 words

The multiple monopolar method of claim 8, further comprising the step of connecting said current source and said impedance processor simultaneously to said individual conductors.

Claim 16

Dependent Claim 37 words

The multiple monopolar method of claim 11, further comprising the step of driving said individual conductors at different frequencies, and discriminating on the basis of frequency between signals appearing on said individual conductors from said monopolar electrodes.

Claim 17

Independent Claim 117 words

A system for use in determining desired heart rate for a patient undergoing cardiac therapy, comprising: means for receiving heart rate data including multiple samples of the patient's heart rate during induced variations thereof at a particular workload; monopolar impedance-based means for measuring the patient's stroke volume during said induced variations in heart rate, said monopolar means including means for measuring impedance between a monopolar electrode positioned in the patient's heart and a distant reference electrode; and means coupled to said receiving means and said monopolar impedance-based means for multiplying said heart rate data by said measured stroke volume to obtain an impedance-based value proportional to the patient's cardiac output during said induced variations in heart rate.

Claim 18

Independent Claim 117 words

A system for use in determining desired heart rate for a patient undergoing cardiac therapy, comprising: means for receiving heart rate data including multiple samples of the patient's heart rate during induced variations thereof at a particular workload; monopolar impedance-based means for measuring the patient's stroke volume during said induced variations in heart rate, said monopolar means including means for measuring impedance between a monopolar electrode positioned in the patient's heart and a distant reference electrode; and means coupled to said receiving means and said monopolar impedance-based means for multiplying said heart rate data by said measured stroke volume to obtain an impedance-based value proportional to the patient's cardiac output during said induced variations in heart rate.

Claim 19

Dependent Claim 33 words

The system of claim 13, further comprising an implantable pacemaker having means for adjustably controlling the patient's heart rate, said pacemaker including telemetry means for transmitting heart rate data to said receiving means.

Claim 20

Dependent Claim 64 words

The system of claim 14, further comprising means for analzing the relationship between the impedance-based value proportional to cardiac output and the patient's heart rate and identifying therefrom the desired heart rate for the patient at said particular workload as the heart rate beyond which the incremental increase in cardiac output for an incremental increase in heart rate is less than a predetermined value.

Claim 21

Dependent Claim 15 words

The system of claim 15 wherein said distant reference electrode is located on said pacemaker.

Claim 22

Independent Claim 102 words

A method of determining desired heart rate for a patient undergoing cardiac therapy, comprising the steps of: inducing variations in the patient's heart rate at a particular workload; measuring the patient's heart rate during said induced variations in heart rate; measuring the patient's stroke volume during said induced variations in heart rate, said step of measuring stroke volume including measuring impedance between a monopolar electrode positioned in the patient's heart and a distant reference electrode; and multiplying measured heart rate by measured stroke volume to obtain an impedance-based value proportional to the patient's cardiac output during said induced variations in heart rate.

Claim 23

Independent Claim 102 words

A method of determining desired heart rate for a patient undergoing cardiac therapy, comprising the steps of: inducing variations in the patient's heart rate at a particular workload; measuring the patient's heart rate during said induced variations in heart rate; measuring the patient's stroke volume during said induced variations in heart rate, said step of measuring stroke volume including measuring impedance between a monopolar electrode positioned in the patient's heart and a distant reference electrode; and multiplying measured heart rate by measured stroke volume to obtain an impedance-based value proportional to the patient's cardiac output during said induced variations in heart rate.

Claim 24

Dependent Claim 49 words

The method of claim 17 wherein said step of measuring the patient's heart rate is performed with an implantable pacemaker of the type having telemetry means for transmitting heart rate data transcutaneously, and wherein said inducing step includes varying the rate of said pacemaker while maintaining a fixed workload.

Claim 25

Dependent Claim 65 words

The method of claim 18, further comprising the step of analyzing the relationship between the impedance-based value proportional to cardiac output and the patient's heart rate and identifying therefrom the desired heart rate for the patient at said particular workload as the heart rate beyond which the incremental increase in cardiac output for an incremental increase in heart rate is less than a predetermined value.

Claim 26

Dependent Claim 15 words

The method of claim 19 wherein said distant reference electrode is located on said pacemaker.

Claim 27

Dependent Claim 67 words

An impedance-based method of detecting ventricular fibrillation of a heart, comprising the steps: measuring pulsatile impedance changes between a monopolar electrode disposed within said heart and a reference electrode outside said heart; and detecting the onset of fibrillation by recognition of a reduction of pulsatile impedance changes in excess of a predetermined amount, and the absence of electrical activity for longer than a predetermined interval of time.

Claim 28

Dependent Claim 67 words

An impedance-based method of detecting ventricular fibrillation of a heart, comprising the steps: measuring pulsatile impedance changes between a monopolar electrode disposed within said heart and a reference electrode outside said heart; and detecting the onset of fibrillation by recognition of a reduction of pulsatile impedance changes in excess of a predetermined amount, and the absence of electrical activity for longer than a predetermined interval of time.

Claim 29

Dependent Claim 21 words

The method of claim 21 wherein said measuring step is performed with said monopolar electrode centrally positioned within the right ventricle.

Claim 30

Dependent Claim 25 words

The method of claim 22 wherein said detecting step includes recognizing a rate of reduction in excess of a predetermined rate characteristic of said heart.

Claim 31

Dependent Claim 70 words

A multiple monopolar system for measuring the stroke volume of a patient's heart, comprising: an intracardiac impedance catheter having a distal end and a proximal end; a plurality of monopolar electrodes axially spaced along the surface of said distal end of said impedance catheter; an extracardial reference electrode; and monopolar means for supplying a drive signal and measuring impedance between each of said monopolar electrodes and said extracardial reference electrode.

Claim 32

Dependent Claim 70 words

A multiple monopolar system for measuring the stroke volume of a patient's heart, comprising: an intracardiac impedance catheter having a distal end and a proximal end; a plurality of monopolar electrodes axially spaced along the surface of said distal end of said impedance catheter; an extracardial reference electrode; and monopolar means for supplying a drive signal and measuring impedance between each of said monopolar electrodes and said extracardial reference electrode.

Claim 33

Dependent Claim 24 words

The multiple monopolar system of claim 24, wherein said monopolar means includes means for obtaining a weighted sum of signals from said monopolar electrodes.

Claim 34

Dependent Claim 77 words

A multiple monopolar method of measuring the stroke volume of a patient's heart, comprising the steps of: introducing into the patient's heart an impedance catheter having a plurality of monopolar electrodes axially spaced along the surface of one end; positioning a reference electrode outside the patient's heart; and supplying a drive signal and measuring impedance between each of said monopolar electrodes and said reference electrode outside the patient's heart for measuring the stroke volume of said heart.

Claim 35

Dependent Claim 77 words

A multiple monopolar method of measuring the stroke volume of a patient's heart, comprising the steps of: introducing into the patient's heart an impedance catheter having a plurality of monopolar electrodes axially spaced along the surface of one end; positioning a reference electrode outside the patient's heart; and supplying a drive signal and measuring impedance between each of said monopolar electrodes and said reference electrode outside the patient's heart for measuring the stroke volume of said heart.

Claim 36

Dependent Claim 22 words

The multiple monopolar method of claim 26, further comprising the step of obtaining a weighted sum of signals from said monopolar electrodes.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-10-21	1995-04-22	1995-10-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-10-21	1999-04-22	1999-10-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-10-21	2003-04-22	2003-10-22	$7700.00	Window Closed / Lapsed

Multiple monopolar system and method of measuring stroke volume of the heart

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