EP0140472A1
Expired / Lapsed
EP
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Stroke volume controlled pacer
Assignee: Medtronic Inc
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Filing: 1984-06-29
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Granted: —
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Expires: 2004-06-29
Abstract
Abstract A rate responsive pacer which paces the heart at a rate dependent on detected variations in the stroke volume of the heart. A lead system 12 is used for impedance measurements to determine the stroke volume in blocks 20 and 100. The stroke volume is compared at 104 with a reference value which itself may be set at 112 in dependence on the heart rate. A resulting difference value is used in block 106 to determine an appropriate change in heart rate and the heart rate is updated at 108. The heart rate is supplied to pacing circuits 24 via a rate limiting stage 110.
Inventors
- 👤 Walter H. Olson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 06:14
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/365; A61N1/36514; A61N1/36521
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
110 words
A cardiac pacer for the therapeutic stimulation of a heart comprising: a lead system for coupling said pacer to the patient's heart; a measuring means coupled to said lead for inferring the stroke volume of said heart from the measurement of a physiologic parameter and for producing a measurement signal indicative of stroke.volume; computation and control means coupled to said measuring means for determining a heart rate value in response to said stroke volume measurement signal;and a pulse generator means coupled to said lead system and said computation and control means for providing stimulation pulses to said heart at a frequency which is a function of said heart rate value.
Claim 2
Dependent Claim
110 words
A cardiac pacer for the therapeutic stimulation of a heart comprising: a lead system for coupling said pacer to the patient's heart; a measuring means coupled to said lead for inferring the stroke volume of said heart from the measurement of a physiologic parameter and for producing a measurement signal indicative of stroke.volume; computation and control means coupled to said measuring means for determining a heart rate value in response to said stroke volume measurement signal;and a pulse generator means coupled to said lead system and said computation and control means for providing stimulation pulses to said heart at a frequency which is a function of said heart rate value.
Claim 3
Dependent Claim
75 words
A cardiac pacer for the therapeutic stimulation of a heart comprising: measuring means for periodically inferring the stroke volume of said heart and for producing a sequence of stroke volume measurements; a pulse generator for providing stimulation pulses to said heart at a frequency proportional to a heart rate value; and means coupled to said measuring means and coupled to said pulse generator for determining a heart rate value in response to stroke volume measurement.
Claim 4
Dependent Claim
75 words
A cardiac pacer for the therapeutic stimulation of a heart comprising: measuring means for periodically inferring the stroke volume of said heart and for producing a sequence of stroke volume measurements; a pulse generator for providing stimulation pulses to said heart at a frequency proportional to a heart rate value; and means coupled to said measuring means and coupled to said pulse generator for determining a heart rate value in response to stroke volume measurement.
Claim 5
Dependent Claim
45 words
A cardiac pacer as claimed in claim 1 or 2 wherein said measuring means is arranged to measure the ventricular volume of said heart at end diastole and at end systole and determine a stroke volume measurement from said end systolic and end diastolic measurements.
Claim 6
Dependent Claim
82 words
A cardiac pacer as claimed in claim 1, 2 or 3 wherein said means for determining a heart rate value comprise: means for comparing the value of said stroke volume measurement with the value of a stroke volume set point for producing a stroke volume difference value; means for determing a heart rate difference value from said stroke volume difference value; and means for adding said heart rate difference value to the previous heart rate value yielding a current heart rate value.
Claim 7
Dependent Claim
24 words
A cardiac pacer as claimed in claim 4 further including means for determining said stroke volume set point value from said heart rate value.
Claim 8
Dependent Claim
22 words
A cardiac pacer as claimed in claim 5 including means for altering the relation between the set point and heart rate values.
Claim 9
Independent Claim
99 words
A method of controlling the escape rate of a pacer comprising the steps of: a) measuring the cardiac stroke volume; b) comparing the measured stroke volume with a stroke volume set point value yielding a stroke volume variation value; c) calculating a heart rate variation value from said stroke volume variation value; d) adding said heart rate variation value to an existing value of heart rate yielding a heart rate summation value; e) calculating an updated heart rate value from said heart rate summation value; and f) setting said escape rate in response to said updated heart rate value.
Claim 10
Independent Claim
99 words
A method of controlling the escape rate of a pacer comprising the steps of: a) measuring the cardiac stroke volume; b) comparing the measured stroke volume with a stroke volume set point value yielding a stroke volume variation value; c) calculating a heart rate variation value from said stroke volume variation value; d) adding said heart rate variation value to an existing value of heart rate yielding a heart rate summation value; e) calculating an updated heart rate value from said heart rate summation value; and f) setting said escape rate in response to said updated heart rate value.
Claim 11
Dependent Claim
22 words
A method as claimed in claim 7 wherein said stroke volume set point value is calculated from the existing heart rate value.
Claim 12
Dependent Claim
23 words
A method as claimed in claim 7 or 8 wherein step (a) includes determining the average of a plurality of stroke volume measurements.
Claim 13
Dependent Claim
27 words
A method as claimed in claim 7, 8 or 9 wherein step (e) includes limiting the updated heart rate value to within predetermined upper and lower limits.
References Cited (Backward Citations)
DE3104938A1
Cited
DE3243094A1
Cited
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