Stroke volume controlled pacer
First Claim
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1. A cardiac pacer for the therapeutic stimulation of a heart comprising:
- lead system means for coupling said pacer to the patient'"'"'s heart;
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 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 measurements wherein said heart rate is defined as the V--V interval;
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 determining a heart rate difference value, wherein said heart rate value is defined as the V--V interval, from said stroke volume difference value;
means for adding said heart rate difference value to the previous heart rate value yielding a current, heart rate value; and
pulse generator means coupled to said lead system and said computational and control means for providing stimulation pulses to said heart at a frequency which is a function of said heart rate value.
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Abstract
A rate responsive pacer which paces the heart at a rate dependent on detected variations in the stroke volume of the heart.
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Citations
6 Claims
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1. A cardiac pacer for the therapeutic stimulation of a heart comprising:
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lead system means for coupling said pacer to the patient'"'"'s heart; 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 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 measurements wherein said heart rate is defined as the V--V interval; 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 determining a heart rate difference value, wherein said heart rate value is defined as the V--V interval, from said stroke volume difference value; means for adding said heart rate difference value to the previous heart rate value yielding a current, heart rate value; and pulse generator means coupled to said lead system and said computational and control means for providing stimulation pulses to said heart at a frequency which is a function of said heart rate value. - View Dependent Claims (4)
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2. A cardiac pacer for the therapeutic stimulation of a heart comprising:
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measuring means for periodically inferring the stroke volume of said heart and for roducing a sequence of stroke volume measurements; pulse generator means for providing stimulation pulses to said heart at a frequency proportional to a heart rate value wherein said heart rate value is defined as the V--V interval; means coupled to said measuring means and coupled to said pulse generator means for determining said heart rate value in response to stroke volume measurement; 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 determining a heart rate difference value, wherein said heart rate value is defined as the V--V interval, 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.
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3. A cardiac pacer for the therapeutic stimulation of a heart comprising:
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measuring means for measuring the ventricular volume of said heart at end diastole and at end systole and for inferring a stroke volume measurement from said end systolic and end diastolic measurements; pulse generator means for providing stimulation pulses to said heart at a frequency proportional to a heart rate value wherein said heart rate value is defined as the V--V interval; computational control means coupled to said measuring means and coupled to said pulse generator means for determining said heart rate value in response to the stroke volume measurement; 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 determining a heart rate difference value, wherein said heart rate value is defined as the V--V interval, 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.
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5. A method of controlling the escape rate of a pacer comprising the steps of:
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(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.
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6. A method of controlling the escape rate of a pacer comprising the steps of:
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(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; (f) setting said escape rate in response to said updated heart rate value; and (g) calculating a stroke volume set point value from said heart rate value.
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Specification