Claims
- 1. A rate adaptive pacer comprising:
- implantable pulse generator means for normally producing cardiac stimulating pulses at a predetermined lower rate;
- sensing means for sensing impedance in the blood in a selected cardiac chamber;
- means for producing a time varying impedance signal proportional to the intracardiac impedance measured in the selected cardiac chamber due to the beating action of the heart;
- means for extracting from the time varying impedance signal a modulation signal due to volume changes;
- means for relating the modulation signal to and extracting quantitative information therefrom with respect to the respiratory activity of the patient in whom the pulse generator means is implanted, the respiratory activity information including that relating both to the respiration interval (I.sub.RESP) and the respiration depth (D.sub.RESP); and
- means for producing a rate control signal from the modulation signal which, when applied to the pulse generator means, changes the rate at which the stimulating pulses are produced from the predetermined lower rate to a higher rate, the interval between the cardiac stimulating pulses is made to vary in accordance with the algorithm: ##EQU4## where a and b are constants, I.sub.RESP is the respiratory interval and D.sub.RESP is the respiratory depth and ##EQU5## are base values relating to values obtained with the patient at rest.
- 2. A rate adaptive pacer comprising:
- implantable pulse generator means for normally producing cardiac stimulating pulses at a predetermined lower rate;
- sensing means for sensing impedance in the blood in a selected cardiac chamber;
- means for producing a time varying impedance signal proportional to the intracardiac impedance measured in the selected cardiac chamber due to the beating action of the heart;
- means for extracting from the time varying impedance signal a modulation signal due to volume changes;
- means for relating the modulation signal to and extracting quantitative information therefrom with respect to the respiratory activity of the patient in whom the pulse generator means is implanted, the respiratory activity information including that relating both to the respiration interval (I.sub.RESP) and the respiration depth (D.sub.RESP); and
- means for producing a rate control signal from the modulation signal which, when applied to the pulse generator means, changes the rate at which the stimulating pulses are produced from the predetermined lower rate to a higher rate, the interval between the cardiac stimulating pulses is made to vary in accordance with the algorithm: ##EQU6## where a, b, c, d, e are numerical constants and ##EQU7## are base values corresponding to values obtained with the patient at rest.
- 3. The rate adaptive pacer as in claim 2 wherein the numerical constants are programmable.
- 4. The rate adaptive pacer as in claim 2 wherein the numerical constants are fixed.
- 5. A rate adaptive pacer comprising:
- implantable pulse generator means for normally producing cardiac stimulating pulses at a predetermined lower rate;
- sensing means for sensing impedance in the blood in a selected cardiac chamber;
- means for producing a time varying impedance signal proportional to the intracardiac impedance measured in the selected cardiac chamber due to the beating action of the heart;
- means for extracting from the time varying impedance signal a modulation signal due to volume changes;
- means for relating the modulation signal to and extracting quantitative information therefrom with respect to the respiratory activity of the patient in whom the pulse generator means is implanted, the respiratory activity information including that relating both tot he respiration interval (I.sub.RESP) and the respiration depth (D.sub.RESP); and
- means for producing a rate control signal from the modulation signal which, when applied to the pulse generator means, changes the rate at which the stimulating pulses are produced from the predetermined lower rate to a higher rate, the interval between the cardiac stimulating pulses is made to vary in accordance with the algorithm: ##EQU8## where a, b c, and d are numerical constants and SV.sub.base, PEI.sub.base, dZ/dt.sub.base, I.sub.RESP and D.sub.RESP are base values relating to values obtained with the patient at rest.
- 6. A rate adaptive pacer comprising:
- implantable pulse generator means for normally producing cardiac stimulating pulses at a predetermined lower rate;
- sensor means for sensing the pressure in a selected cardiac chamber;
- means for producing a time varying signal proportional to the pressure measured in the selected cardiac chamber due to the beating action of the heart;
- means for extracting from the time varying pressure signal a modulation signal due to pressure changes;
- means for relating the modulation signal to and extracting quantitative information therefrom relating to the respiratory activity of the patient in whom the pulse generator means is implanted, the respiratory activity information including that related to the respiration interval (I.sub.RESP) and the respiration depth (D.sub.RESP); and
- means for producing a rate control signal from the modulation signal which, when applied to the pulse generator means, changes the interval between the stimulating pulses produced from said predetermined lower rate to a higher rate in accordance with a known relationship between I.sub.RESP and D.sub.RESP expressed as the following empirical algebraic function: ##EQU9## where a and b are constants, I.sub.RESP is the respiratory interval and D.sub.RESP is the respiratory depth and I.sub.RESP and D.sub.RESP are baseline values relating to values obtained with the patient at rest.
- 7. A rate adaptive pacer comprising:
- implantable pulse generator means for normally producing cardiac stimulating pulses at a predetermined lower rate;
- sensor means for sensing the pressure in a selected cardiac chamber;
- means for producing a time varying signal proportional to the pressure measured in the selected cardiac chamber due to the beating action of the heart;
- means for extracting from the time varying pressure signal a modulation signal due to pressure changes;
- means for relating the modulation signal to and extracting quantitative information therefrom relating to the respiratory activity of the patient in whom the pulse generator means is implanted, the respiratory activity information including that related to the respiration interval (I.sub.RESP) and the respiration depth (D.sub.RESP); and
- means for producing a rate control signal from the modulation signal which, when applied to the pulse generator means, changes the interval between the stimulating pulses produced from said predetermined lower rate to a higher rate in accordance with a known relationship between I.sub.RESP and D.sub.RESP expressed as the following empirical algebraic function: ##EQU10## where D.sub.RESP and I.sub.RESP are baseline values corresponding to values obtained with the patient at rest.
- 8. A rate adaptive pacer comprising:
- implantable pulse generator means for normally producing cardiac stimulating pulses at a predetermined lower rate;
- sensor means for sensing the pressure in a selected cardiac chamber;
- means for producing a time varying signal proportional to the pressure measured in the selected cardiac chamber due to the beating action of the heart;
- means for extracting from the time varying pressure signal a modulation signal due to pressure changes;
- means for relating the modulation signal to and extracting quantitative information therefrom relating to the respiratory activity of the patient in whom the pulse generator means is implanted, the respiratory activity information including that related to the respiration interval (I.sub.RESP) and the respiration depth (D.sub.RESP); and
- means for producing a rate control signal from the modulation signal which, when applied to the pulse generator means, changes the interval between the stimulating pulses produced from said predetermined lower rate to a higher rate in accordance with a known relationship between I.sub.RESP and D.sub.RESP expressed as the following empirical algebraic function: ##EQU11## where a, b, c, d, and e are numerical constants and .DELTA.P.sub.BASE, PEI.sub.BASE, (dP/dt)P.sub.BASE, I.sub.RESP, and D.sub.RESP are baseline values corresponding to values obtained with the patient at rest.
- 9. The rate adaptive pacer as in claim 8 wherein the numerical constants are programmable.
- 10. The rate adaptive pacer as in claim 8 wherein the numerical constants are fixed.
- 11. A rate adaptive pacer comprising:
- implantable pulse generator means for normally producing cardiac stimulating pulses at a predetermined lower rate;
- sensor means for sensing the pressure in a selected cardiac chamber;
- means for producing a time varying signal proportional to the pressure measured in the selected cardiac chamber due to the beating action of the heart;
- means for extracting from the time varying pressure signal a modulation signal due to pressure changes;
- means for relating the modulation signal to and extracting quantitative information therefrom relating to the respiratory activity of the patient in whom the pulse generator means is implanted, the respiratory activity information including that related to the respiration interval (I.sub.RESP) and the respiration depth (D.sub.RESP); and
- means for producing a rate control signal from the modulation signal which, when applied to the pulse generator means, changes the interval between the stimulating pulses produced from said predetermined lower rate to a higher rate in accordance with a known relationship between I.sub.RESP and D.sub.RESP expressed as the following empirical algebraic function: ##EQU12## where a, b, c, and d are numerical constants, ##EQU13## are base values relating to values obtained with the patient at rest.
Parent Case Info
This is a continuation of copending application Ser. No. 07/490,352 filed on Mar. 8, 1990 now abandoned.
US Referenced Citations (16)
Foreign Referenced Citations (5)
Number |
Date |
Country |
299208 |
Jan 1989 |
EPX |
310024 |
Apr 1989 |
EPX |
310026 |
Apr 1989 |
EPX |
310025 |
May 1989 |
EPX |
218007 |
Apr 1985 |
DEX |
Non-Patent Literature Citations (1)
Entry |
A Cardiac Pacemaker with Activity-Dependent Rate Regulation, H. D. Funke, Jun. 1975, pp. 225-228, Biomedizinische Technik, Band 20. |
Continuations (1)
|
Number |
Date |
Country |
Parent |
490392 |
Mar 1990 |
|