EP0541338A1
Expired / Lapsed
EP
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Implantable cardiac function monitor and stimulator for diagnosis and therapy delivery
Assignee: Cardiac Pacemakers Inc
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Filing: 1992-11-03
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Granted: —
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Expires: 2012-11-03
Abstract
Abstract An implantable monitor/stimulator is disclosed that monitors and assesses indices of cardiac function, including the strength and timing of cardiac contraction, then automatically executes a physician-selected mode of therapy. It accomplishes this by assessing impedance, electrocardiogram, and/or pressure measurements, then calculating various cardiac parameters. The results of these calculations may be stored within the device, telemetered to an external monitor or display and/or may be used by the physician to determine the mode of therapy to be chosen. If indicated, therapy is administered by the device itself or by telemetering control signals to various peripheral devices for the purpose of enhancing either contraction or relaxation of the heart. The cardiac parameters that are calculated all provide an assessment of level of cardiac function by monitoring changes in ventricular filling and ejection or by calculating isovolumic phase indices of heart contraction. Examples of such parameters are ejection fraction, cardiac output, stroke work, and/or various pressure-volume relationships. These parameters determine the mode of therapy that will be selected by a physician. Choices of therapy include several forms of pacing of cardiac or skeletal muscle, and telemetry to implanted or external units for drug infusion or for monitoring by a central data system.
Inventors
- 👤 Rodney W. Salo
- 👤 Bruce A. Tockman
- 👤 Morton M. Mower
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 18:27
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/36042; A61N1/362; A61N1/365; A61N1/36585; A61M; A61M5/00; A61M5/14; A61M5/168; A61M5/172; A61M5/1723; A61N1/3627
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
93 words
Apparatus for applying therapy to a patient based upon the contractile state of said patient's heart, comprising in combination: (a) intracardiac sensing means for sensing hemodynamic indicators of contractile state in at least one ventricular chamber of the heart; (b) means coupled to said sensing means for developing a control signal varying as a function of said hemodynamic indicators; (c) patient therapy means having at least one stimulating electrode for applying stimulating pulses to tissue; and (d) means for applying said control signal to said patient therapy means, for changing said contractile state.
Claim 2
Dependent Claim
94 words
Apparatus for applying therapy to a patient based upon the contractile state of said patient's heart, comprising in combination: (a) intracardiac impedance sensing means for sensing ventricular volume in at least one ventricular chamber of the heart; (b) means coupled to said sensing means for developing a control signal varying as a function of said ventricular volume; (c) patient therapy means having at least one stimulating electrode for applying stimulating pulses to tissue; and (d) means for applying said control signal to said patient therapy means for increasing said contractile state of said heart.
Claim 3
Dependent Claim
100 words
Apparatus for applying therapy to a patient based upon the contractile state of said patient's heart, comprising in combination: (a) intracardiac pressure sensing means for sensing the pressure in at least one ventricular chamber of the heart; (b) means coupled to said sensing means for developing a control signal varying as a function of said pressure due to beating action of the heart; (c) patient therapy means having at least one stimulating electrode for applying stimulating pulses to tissue; and (d) means for applying said control signal to said patient therapy means, for increasing said contractile state of said heart.
Claim 4
Dependent Claim
149 words
Apparatus for applying therapy to a patient based upon the contractile state of said patient's heart, comprising in combination: (a) intracardiac impedance sensing means for sensing ventricular volume in at least one ventricular chamber of the heart; (b) intracardiac pressure sensing means for sensing pressure in at least one ventricular chamber of the heart; (c) first control signal means coupled to said impedance sensing means for developing a control signal varying as a function of said ventricular volume; (d) second control signal means coupled to said pressure sensing means for developing a control signal varying as a function of said pressure; (e) patient therapy means having at least one stimulating electrode means for applying stimulating pulses to tissue; and (f) means for applying said first and second control signals to said patient therapy means for increasing said contractile state in relation to said changes in ventricular volume and pressure.
Claim 5
Independent Claim
55 words
The device as in any one of Claims 1, 2 or 4, wherein said patient therapy means receives a further control signal varying as a function of ejection fraction, wherein ejection fraction is computed by dividing a control signal value selected to indicate stroke volume by a control signal value selected to indicate end-diastolic volume.
Claim 6
Independent Claim
58 words
The device as in any one of Claims 1, 2 or 4, wherein said patient therapy means receives a further control signal varying as a function of cardiac output, wherein cardiac output is calculated as the product of a control signal value selected to indicate sensed heart rate times a control signal value selected to indicate stroke volume.
Claim 7
Dependent Claim
100 words
The device as in Claim 2, wherein said sensing means is further coupled to means for developing a pressure control signal, said pressure control signal means including: (a) means for producing a time varying signal proportional to pressure measured in one cardiac chamber due to the beating action of the heart; (b) means for extracting from said time varying signal a modulation signal due to pressure changes in said cardiac chamber; and (c) means for producing a pressure control signal from said modulation signal which, when applied to said patient therapy means, results in change in the heart's contractile state.
Claim 8
Dependent Claim
101 words
The device as in Claim 3, wherein said pressure sensing means is further coupled to means for developing an impedance control signal, said impedance control signal means including: (a) means for producing a time varying signal proportional to impedance measured in one cardiac chamber due to beating action of the heart; (b) means for extracting from said time varying signal a modulation signal due to impedance changes in said cardiac chamber; and (c) means for producing an impedance control signal from said modulation signal which, when applied to said apparatus for applying therapy, results in change in the heart's contractile state.
Claim 9
Dependent Claim
76 words
The device as in Claim 4, further including: a microprocessor for computing the area inside a curve obtained by integration of a plot of pressure as a function of volume, as an indicator of stroke work; a means coupled to said microprocessor for developing a stroke work control signal varying as a function of said stroke work; and means for applying said stroke work control signal to said patient therapy means, for changing said contractile state.
Claim 10
Dependent Claim
80 words
The device as in Claim 4, further including: a microprocessor for computing the slope of a regression line plotted through maximal pressure/volume points taken at end-systole of the cardiac cycle, as an indicator of ejection phase contractility; a means coupled to said microprocessor for developing an ejection phase control signal varying as a function of said indicator of ejection phase contractility; and means for applying said ejection phase control signal to said patient therapy means, for changing said contractile state.
Claim 11
Dependent Claim
70 words
The device as in Claim 4, further including: a microprocessor for computing a curve resulting from a plot of minimum diastolic pressure against end-diastolic volume, as an indicator of diastolic function; a means coupled to said microprocessor for developing a diastolic function control signal varying as a function of said curve; and means for applying said diastolic function control signal to said patient therapy means, for changing said contractile state.
Claim 12
Independent Claim
117 words
The device as in any one of Claims 1, 2, 3 or 4, wherein said patient therapy means further includes: means for applying said stimulating pulses from said stimulating electrode to the heart in a predetermined pattern for increasing the strength of contraction of said heart, wherein said predetermined pattern of stimulating pulses includes a pair of pulses, said pair comprising delivery of a first stimulating pulse that is one of intrinsic and paced, followed by a delay in a range of 150 to 200 msec, then delivery of a second stimulating pulse in the form of a pacing pulse, delivered to the right ventricle of the heart, to increase the strength of contraction of said heart.
Claim 13
Independent Claim
84 words
The device as in any one of Claims 1, 2, 3 or 4, wherein said patient therapy means further includes: means for applying said stimulating pulses from said stimulating electrode to the heart in a predetermined pattern for increasing the strength of contraction of said heart, wherein said predetermined pattern of stimulating pulses includes biventricular pacing, said biventricular pacing pattern including delivering substantially simultaneous pacing pulses to two sites within the chambers of the heart to increase the strength of contraction of said heart.
Claim 14
Independent Claim
85 words
The device as in any one of Claims 1, 2, 3 or 4, wherein said patient therapy means further includes: means for applying said stimulating pulses from said stimulating electrode to at least one site in the heart in a predetermined pattern for increasing the strength of contraction of said heart, wherein said predetermined pattern of stimulating pulses includes a burst pattern, said burst pattern including delivering from 1 to 12 stimulating pulses at a frequency in the range of from 10 to 130 Hz.
Claim 15
Independent Claim
133 words
The device as in any one of Claims 1, 2, 3 or 4, wherein said patient therapy means further includes: means for applying said stimulating pulses from said stimulating electrode to the heart in a predetermined pattern for increasing the strength of contraction of said heart, wherein said predetermined pattern of stimulating pulses includes a pattern of intercalated pacing, comprising delivery of at least one extrastimulus to the right ventricle; a delay means for calculating a delay of a preset interval after said control signal indicates the presence of a conducted heartbeat; and means for developing an intercalated control signal for causing said patient therapy means to deliver at least one extrastimulus to the right ventricle, thereby extending a relaxation period of the heart to enhance the strength of contraction of said heart.
Claim 16
Independent Claim
57 words
The device as in any one of Claims 1, 2, 3 or 4, wherein said patient therapy means further includes: skeletal muscle stimulating means for applying a predetermined pattern of stimulating pulses from said stimulating electrode to a skeletal muscle that has been surgically attached to the heart, for increasing the strength of contraction of said heart.
Claim 17
Independent Claim
37 words
The device as in any of Claims 1, 2, 3 or 4, wherein said means for applying said control signal to said patient therapy means further includes telemetry means for transmitting and receiving radio frequency encoded signals.
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