CA1243361A - Stroke volume controlled pacer - Google Patents

Stroke volume controlled pacer

Info

Publication number
CA1243361A
CA1243361A CA000457692A CA457692A CA1243361A CA 1243361 A CA1243361 A CA 1243361A CA 000457692 A CA000457692 A CA 000457692A CA 457692 A CA457692 A CA 457692A CA 1243361 A CA1243361 A CA 1243361A
Authority
CA
Canada
Prior art keywords
value
stroke volume
heart
heart rate
rate value
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000457692A
Other languages
French (fr)
Inventor
Walter H. Olson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Medtronic Inc
Original Assignee
Medtronic Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=24027220&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=CA1243361(A) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Medtronic Inc filed Critical Medtronic Inc
Application granted granted Critical
Publication of CA1243361A publication Critical patent/CA1243361A/en
Expired legal-status Critical Current

Links

Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362Heart stimulators
    • A61N1/365Heart stimulators controlled by a physiological parameter, e.g. heart potential
    • A61N1/36514Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by a physiological quantity other than heart potential, e.g. blood pressure
    • A61N1/36521Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by a physiological quantity other than heart potential, e.g. blood pressure the parameter being derived from measurement of an electrical impedance

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 measuring device periodically infers the stroke volume of the heart and produces a sequence of stroke volume measurements and a pulse generator provides stimulation pulses to the heart at a frequency proportional to a heart rate value. A device coupled to the measuring device and the pulse generator determines a heart rate value in response to stroke volume measurement.

Description

STROI;E VOLllMr CONTROLLEn PACER

BACKGROIIND ~F TIIE INVENT1ON
~ . . . .
This invention relates generally to the -field of carcliac pacemakers and more particularly to a pacemaker 5 having an escape intfrval which is set in response to a medsured physioloyic variahle of -the patient.
When the body undergces exercise a variety of changes take place. These include an increase in respiration diversion of hlood flow to the active 10 skeletal muscles and arI increase in cardiac output.
These changes cooperate to deliver an incredsed arnount of oxygen and nutrients to the active muscles.
-The mass flow rate o-f oxygenated blood from the heart is referred to as the cardiac output of the heart and it 15 is equal to the product of the heart rate in beats per minute dnd the heart s stroke volume in litres.
The increase in cardiac output is achieved by an increase In the stroke volume o~ the heart; up to two fo)d~
as well as an increase in the heart rate; up to three 20 fold.
The changes in stroke volume are mediated by venous return contractility and afterload while thr changes in the heart s rate are mediated through -the autonomic nervous system which operates on a structure called the ~5 S-A Node.
The S-A Node is located on the atria of the heart.
An electrical signal generated by this natural pacernaker causes the at ia or upper chambers of the heart to contract. This forces blond into the lower chambers or 30 ventricles of the heart. The signal from the S~A Node is propagated to the lower ch~dmI)ers of Lhe heart through a structure called the Atrio-VentricuIar or A-V Node after a brief delay. The signal -frôm the A-V Node cdusras the ventricles to contract forcing the blood throughout the 35 body.

.- ~

33~i~
-2-Many forms of hedrt disease imnaiI the function of the S-A and A-~ No~es, and their associated conductive tissues. Patient's exhit~5ting these in(licdtions mdy be candidates -for artificial pacemaker therapy.
S Initially, pacelnakers wele implanted in patients who exrlibited complete A-V block. This conduction disturbance is manifested by the inability of the signal from the S-A
Node to reach the lower challlbers of tlle heart to in-itiate a ventricular contractiorl.
The earliest form uf implantable pacernaker for the long-term stim~lldtion of the heart is known from lJ.S.
Patent No. 3,057,356 issued to W. Greatbatch~ This asynchronous pdcemaker, in essence, replaced the heart's natural conduction system and periodically provided an 15 electrical stinlulus to the ventricle to cause contractions.
In some patients, the A-V block condition is intermittant and occasionally the artificial pacemaker and the natural S-A Node of the heart compete for control of 20 the velltricular action of the heart. This competition is undesirable. The demand pacelnaker avoids this competitive pacing. An example of an implantable version of the demand pacemaker is known From U.S. Patent No. 3,47~,74r5, to W. Greatbatch.
In operation, the demand mode pacemaker senses the ventricular contraction of the heart, and provides stimulation to the ventricles only in the absence of naturally occurring contractions of the heart. Such demand pacemakers synchronize their timing witll the heart 30 and provide stimulated bedts if the natural cardiac rhyth drops below a preset rate. Both the asynchronous and demand type of pacemaker thus provided for a fixed lower rate for the patient's healt rate.
When a patient has no intrinsic rhythrn and is being 35 paced at a fixed rate, any increment in demand for cardiac output must come solely from naturally induced changes in stroke volume. For these patients, strenuous work is impossible since stroke volume chan~es alone are insl~fficient to raise the cardiac output enough to supply the skeletal muscles dur-ing heavy exercise.
~y way of contrasl, the P-syncllronous mocle of 5 pacemaker, as exemplified by U.S. Patent No. 3,253,596 to J. W. Keller, monitored electrical activity in the atrium~ and triggered a ventricular action after a short tirne period. This form of pacemaker permits the patient's naturally occurring atrial rate to control the rate o-f 10 ventricular stimulation.
Other pacernakers which exhibit -the atrial tracking feature include the atr-ial-synchronized, ventricularly inhibited pacemaker known -frorn U.S. Patent No. 396~,707 to W. Greatbatch, as well as the dual-sense, dual-pace 15 pacemaker known fronl U.S. Patent No. 4,3129355 to H.
Funke~ The advantage of atrial synchronized pacing is that it permits the pacernaker's rate -to be determined by the S-A Node which in turn intreprets the body's demand for cardiac ou-tput.
Another forrn of rate adaptive pacer is known from ~S. Patent No. 4~29~007 to ~right et al. This device monitors the atrial ra-te and alters the ventricular escape interval in response to the atrial rate.
For these patients, the pacemaker mimics the natural 25 conductive system of the heart and increased demand for cardiac output comes froM both an increase in heart rate controlled by the S-A Node as well as concomitan-t increase in stroke volume.
I-lowever, in many patienks, the S-A Node is not a 30 reliable source of information concerning the body's demand for cardiac outpu-t. Incorporatin~ an S-A Node replacement to provide rate adaptive pacin~ would be desirable.
One form of rate responsive pacemaker which relies on 35 the detection of blood saturation of oxygen is known from U.S. Patent No. ~,202,339 to Wirtzfield. This device u-tilizes an optical measurill~J probe which is inserted into ~33~

the heart -to monitor the oxygen saturation of the blood. This measurement is then used to alter the stimulating -frequency of an associated pacemaker.
Another form of rate responsive pacemaker is known from United States Patent No.4,009,721 to Alcidi. This device utilizes a pll measurement probe which alters the pacemaker's rate in response to the measurement of blood pH.
Another form of rate adaptive pacemaker is known from United Sta-tes Patent No.~,140,132 to Dahl, which utilizes an accelerometer to monitor the physical activi*y of the patient, and which alters the pacemaker's escape interval.
Another form of rate adaptive pacer is known from United States Patent No.4,228,803 to Rickards. This patent discloses a pacer which monitors the Q-T interval of the cardiac cycle and increases the pacer rate in response to shortening of the Q-T interval.
Each of the preceding pacemakers has taken advantage of a physiologic parameter which varies with the body's demand for cardiac output.
DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a block diagram of a pacemaker incorpora-ting the invention.
FIGURE 2 is a flow chart and a functional block representation of the algorithm of the present invention.
FIGURE 3 is sequence of graphs which illustrate the relationship between the stroke volume and rate of the heart.
Re-turning to cardiac physiology, and in reference to FIGURE 3A it :is important to note that the cardiac output of-the heart, measured :in litres oE
blood per minute, is -the product o:E the patient's heart ra-te times the stroke volume of the heart. The figure shows a family of constant cardiac output
3~

curves callecl isopleths corresponding to cardiac outputs of 1 to 6 L/M.
As previously indicated, increased physical activity in normal individuals, results in an increased cardiac output. In the normal heart, both the heart rate and the stroke volume increase to satis~y the body's need for oxygenated blood. Studies by Versteeg (1981) show that for exercise this cardiac transfer function is a first order linear function with a 10-12 second time constant. This normal cardiac response to increasing work loads is shown by the cardiac load line 300 on l:IGURE 3A. In the figure, a work load corresponding to cardiac output of 2L/M is met by a heart rate of 75 bpm at a stroke volume of 26 ml. An increase in work load calling for a cardiac output of 5L/M is met wi~h a rate increase of 1~0 bpm and a stroke volume increase to 36 ml.
In -those patients who have complete heart block and a fixed-rate pacemaker, it has been noted that increased demand for cardiac output due -to physical exertion results in an increase in the measured stroke volume of a patientls heart. This is depicted in FIGURE 3B, where the load line 310 corresponds to pacing at a fixed rate, as in asynchronous (V00), demand pacing (VVI) or A-V sequential (DVI) pacing. This figure indicates that those paced patients who have S-A Node dysfunction can only change s-troke volume in response to exercise. Ior example, at 2 L/M of cardiac output th:is patient exhibits a stroke volume of 20 ml at a rate of 100 bpm. An increase to 5 L/M
calls for a stroke volume increase to 5() ml which may well be beyond the patien-t's capabi:Lity.
Thus, the prior art discloses rate adaptive pacers which monitor a physiologic parameter.
Additionally, the response of the hear-t's s-troke volume to physical exertion is well-known in -the art.

67~2-250 BRIEF SUMMARY OF THE INVENTION
_.
In contrast to these preceding forms of rate variable pacemakers, the pacemaker of the present invention moni.tors the s-troke volume of the patient and al-ters the pacing rate in accordance wi-th an algorithm. The sys-tem controls the patien-t's heart rate and also permits the s-troke volume of the patient's heart to vary over a controlled range.
In accordance with a broad aspect of -the invention there is provided a cardiac pacer for the therapeutic stimula-tion 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 parame-ter and fcr 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 s-troke volume measurement with the value of a s-troke volume set point for producing a stroke volume difference value;
means for determining a heart ra-te difference value, wherein said heart rate value is defined as -the V_ V interval, from said stroke volume difference value;
means for adding said hear-t 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.
In accordance wi-th another broad aspect of the invention there is provided a cardiac pacer for the therapeutic stimulation of a hear-t comprising:
measuring means for periodically inferring the stroke volume of said heart and for producing a sequence of stroke volume measurements;
pulse generator means for providing stimulation pulses to said heart at a frequency proportional to a hear-t rate value wherein said hear-t 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 hear-t rate di:Eference value, wherein said hear-t ra-te 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.
In accordance with another broad aspect of -the invention, there is provided a cardiac pacer for the therapeutic stimulation -6a-of a heart comprising:
measuring means for measuring the ven-tricular volume of said heart a-t end dias-tole and a-t end systole and for inferring a stroke volume measurement from said end sys-tolic and end diastolic measurements;
pulse yenerator means Eor providing stimulation pulses to said heart at a frequency propor-tional to a heart rate value where in said hear-t ra-te value is defined as the V--~V interval;
computa-tional 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 pro-ducing a stroke volume difference value;
means for determining a heart rate difference value,wherein said heart rate value i5 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.
DESCRIPTION OF THE PREFERRED EMBODIMENT
__ __ _ __ _ The present invention combines three pacer subsys-tems with the hear-t to form a closed loop pacer for pacing the heart.
I:n FIGURE 1, -the heart 10 is coupled -to a stroke volume measurement appaxatus 20 through a lead system 12. The stroke volume measurement system 20 delivers in:Eormation regarding the stroke volume of the heart -to computa-tion and control locJic 22.

-6b-~%~33~
6~2-25~

This apparatus utilizes information related to stroke vol:ume to determine a desired pacing rate for the heart. Rate control information is provided to a pulse generator 2~ which may provide stimulation -to the heart 10 through lead system 12. The pulse generator 24 may operate in any of the known stimulation modes.
However, the algorithm is described in the con-text of a rate variable asynchronous or VOO mode pacer. A system suitable for incorporating the output data oE -the algorithm into a demand mode pacer may be found in Canadian Patent Application Serial No.

416,050 filed 22 November, 1982 and assigned -to the Assignee of the present invention.
STROKE VOLUME MEASUREMENT SYSTEM
In response to an increase in demand for cardiac output the normal heart increases both its rate and stroke volume. The present invention utilizes the body's demand for cardiac output to control the rate of pacing. This technique requires a reliable measurement of a physiologic variable which is related to cardiac stroke volume.

-6c-Stroke volurme may be inferred by a variety o-f rneasurements taken in the right or le-ft heart including pressure-time histories of arterial blood Flow as ~ell as direct flow measurements in the ma~jor blood vessels of the 5 heart.
Another method of deterrnining the s-troke volume of the heart is through the tecllnique of impedance plethysrnography. This technique has been widely studied (Rushmer 1953 Geddes 19~6 Baan 19~1). In this technique lO an electrode system is inserted into the rigilt or left heart. As shown in FIG. 1 current is passed frorn an anode 13 to a cathode 1~ and the voltage between the electrode pair is measured. I'he accuracy of this method may be increased by utilizing a rnultiplicity of electrode pairs.
15 (Baan 19~1). The magnitude of the voltage measurements from the sensing electrode pairs is a function of the impedance of the heart cavity (Zm) This impedance is in turn, a function of the volume of the chamber. In general volume res-istivity of the l)lood remains constdllt 20 and the magnitude of the voltage sensed depends solely upon the volume of the chdnlber during the measllrelnent.
One may measure chamber volume sequentially (~l~
Z2~ . . . Zn~) over the en-tire cardiac cycle and can be used to ascertain the maxima and minima of cardiac chalnber 25 volume. However in general~ the maximum cardiac volume is achieved at end diastole just prior to -the contrdction of the ventricle. Likewise t~e minimum volume of the ventricle occurs at thr end of the contractiorl of the ventricular muscles called end systole. By rneasuring the 30 heart volume at end systole and end diastole the stroke volurne measurement apparatus may determine the stroke volurne for tilat cardiac contraction or cycle. The computation and control circuitry which receives the stroke volume measurement information may average the 35 stroke volume measurements over a nurnber of cardiac cycles or may operate on a beat-to-beat basis. Further detai'ls regardirlg the measllrenlent of stroke vo'lume through - ~ -the use of an intrdcard ac cathetel may be found in Cardiovascular Research 1981 15 328-334 COMPUTATION AND CONTROI APPARATUS
The structural and -functional aspects of computation 5 and control system 22 are shown in FIG. 2.
The computation and control system 22 receives stroke volume informatiorl labeled SVm on a beat-to-beat basis from the stroke volume measurement system 20 which in turn, is coupled to heart 10. The computa-tion and control 10 system 22 operates on this information and generdtes a heart rate value la~el~d HRN. This rate infolmatioll is used to control the escape interval of the pulse generator 2~ portion of the pacer.
The series of sequential stroke volume measurements 15 denoted [SVm SVm~1 SVm+2...] are delivered to a computational block 100 which calcula-tes an average stroke volume value~ denoted SVM by adding together the values of M measurements and then dividing by M. This process may be expressed:
M
1 SVM=1/M ~ SVm m=1 Experiments have been performed on do~s where the value of M has been varied from 1 to 12. The control 25 algorithm appears to be rela~ively insensitive to this interval and a value of M=1 may be taken dS a representative value.
The measured value of average stroke volume SVM is compared with d reference value for stroke volume denoted 30 SVR. The value for SVR -is calculated by functional block 112 which will be described shortly.
The cornparison betweell SVM and the stroke volume set point SVR is accompl-ished by functional node 10~
which calculates the difFerence between the two values 35 yielding a difference value denoted ~SVM.

~3~
g The value of~ SVM is used to calculate a value of the change in heart rate value denoted~HRn in -the figure. This computdtion -is performed in functional block 106. Experimental work has been performed with a linear 5 relationship hetween ~SVM and the computed value of HRn expressed:
2 ~HRn--K3~SvM
~ lowever other relationships sdtisfying the general expression~ HRn=f(~SVM) may prove workable.
The proportionality constant K3 has units of beats per minute/liter. The value of K3 affects the response tirne of the system -to changes in the measured stroke vol~me. It appears from animal experimentation that the value of K3 is not critical ~or the s-tabi~iity of the 15 system. A typical value for K3 may be taken as 600 bpm/L .
The vallle of HR~I computed as a function of SVM is used to update the exis-ting value for heart rate denoted HRn 1 This calculation is performed at node 108 20 where the value of change in heart rate (~HRn) is added to the preceding value of heart rate (HR" 1). It is important that this operation preserves the sign o-f the change of heart rate, so tha-t the updated value of heart rate can increase or decrease in comparison with the 25 preceding value.
The updated value for heart rate (HRn) is permitted to range between a minimuln heart rate value (HRnlin) and a maxinlunl heart rate value (HRInax). The rate limit check is per-formed by functional block 110. The value of the hear-t 30 rate delivered to the pulse generator 24 is denoted HRN
where HRN=f~HRn). Ihe computed value for HRN replaces the prexisting value for HRrl-1 stored at lll for use at node 108. This value is used to calculate a new value for the stroke volume re-ference value SVR at functional 35 block 112 as follows.
The stroke volume reference value SVR is set to an initial value SVo during systeln initiali2at-ion (norlnal resting value)O Subsequent values are computed as a func-tion of the heart rate value SVR=SVo~K2HRn_1 where the reference value is a linear func~ion of the existing value of heart rate.
5 However other relationships satisfying the general expression: SVR~f(HRN-I) rnay prove workable.
The value of SVO sets the operating point of the control systern as will be discussed with reference to FlGs. 3c and 3d. The value of the proportionality 10 constant K2 controls the slope of the cardiac load line discussed in connection with FlGs. 3c and 3d.
The values for the 2veraging interval M the initial stroke volume set point SVO and K2 and K3 are likely to be patient specific parameters and it may prove 15 desirable to permit alteration of these values by the physician to adapt the pacer to the patient. Likewise the values of HRmax and HRmin may be physician alterable to adapt the stimulation rate to the needs of the patient.

Pulse Generator System 24 The HRN signal is accepted by the pulse generator system 24 and interpreted as an escape interval for the pacemaker function of the device. In operationS -the pacemaker escape interval will vary with the measured 25 stroke volume of the heart. As previously indicated during exercise the escape interval o-f the pacemaker will shorten. If the heart fails to beat within the designated escape interval, then a pacing stimulus will be provided, from pulse amplifier 27 to the heart through sensing 30 stirnulating electrode 11 as shown in FIG. 1. If a natural heal~tbeat is detected prior to the expiration of the escape interval through sensing stimulating electrode 11, a sense amplifier 26 will inhibit the delivery of the pacing s-timulus. Either or both chambers of the heart rnay 35 be stimulated by the pulse generator and the device may operate in an inhibited mode.

3~

It should be recognize~, however, that the stroke volume controlled system can be incoporated into an atrial tracking pacemaker moddlity wherein the ultimate escape interval of the pacemaker may be influenced by the 5 detected atridl rdte o~ the hedrt as well as by variations in the patient's cardi dC stroke volume.

The objective of this stroke volume controlled pacer is to achieve a pacernaker escape interval which reflects 10 the patient's physiologic demand for cardiac output.
The illpUt signal to this control system is the stroke volume of the patient's heart and the output variable of this system is the pacemaker's escape interval.
Experimental data has been taken with a blood flow 15 meter attached to the aorta of the heart, thus providing a direct measure of the stroke volume of the heart, on a beat by beat basis. It is expectedl however, that for a fully implantable system it will be preferable to use the impedance plethysmography approach previously described.
20 The integral of the mass ~low rate signal from the transducer provides a sequence of stroke volume measurements S~lm. These values may be averaged over a multiple number of cardiac cycles to provide a measure of the average stroke volume of the heart. If a very small 25 number of cycles is used, it is possible that the beat-to-beat v~riation in the patient's stroke volume may cause the control sys-tem to generate a sequence of escape intervals which dither about a physiologicdlly optimunl escape rate. On the other hand, if the number of beats 30 taken to form the averaye is large, the response time of the control system may be insufficient to provide the requisite cardiac output for the instantaneous work level of the patient. Experimental work indicates that a value of M = l is suitable for a canine with induced heart 35 block.
The average stroke volume value SVM is comparecl with a stroke volume reference value which may be selected :; ~

~33~

by tile physician and which is constrained within limits.
If this stroke volume reference value is fixed at a specific stroke volume value, then the cardiac load line 320 as shown in FIG. 3C~ will have an infinite slope.
5 Under this regime, small increments in stroke volume due to increments in the exercise level o~ the object result in relatively large increments in hear-t rate, thus forcing the stroke volume of the heart back toward the se-t point reference SVR. In this operating mode the patient is 10 paced at a rate which results in a fixed stroke volume for the heart. Experimental research with canine reveals a poten-tial defect of fixed stroke volume pacing. As indicated in FIG. 3c, an escape interval dictatPd by fixed stroke volulne may call for heart rates subslantially above 15 those which are safe for the subject.
By permitting the stroke volume re-ference point value to vary within constrained limits, one can con-trol the slope of the cardiac load line. Permitting the stroke volume reference point value to vary over a range of 20 approximately 30 ml results in a control system response depicted by FIG. 3d.
In this system the instantaneous value of the stroke volume re~erence poin-t SVR is a function of the instantaneous value of the heart rate. The linear 25 relationship depicted by functional block 112 of FIG. 2 results in a cardiac load line 330 as shown in FIG. 3D.
While a larger value of the portionality constant K2 as shown by curve 112b in FIG. 2 results in a cardiac load line similar to cardiac load line 3~0 in FIG. 3D. Thus, 30 the proportionality constant K2 controls the slope of the cardiac load line and may vary -the cardiac response from that observed in fixed rate pacing as depicted in FIG. 3B
to that which results from pacing to a fixed stroke volume depicted in FIG. 3C. An appropriate value for K2 must be 35 selected by the physician based upon informàtion 67~2-250 concerning the subject patient's heart contractility and stroke volume variations.
The initial value of the stroke volume set point is taken as SV0 which may also be a physician programmable variable in the pacemaking sys-tem. This value controls the initial opera-ting point Eor the system at resting values of cardiac output.
The variation in stroke volume rneasuremen-t compu-ted at nocle 104 is utilized to calculate the change in hear-t rate of the pace-maker in functional bnock 106. Once again a linear rela-tionship between -the change in heart rate and the change in s-troke volume is illustrated in functional block 106. It is qui-te likely that other functions may be suitable for these relationships.
The value of the proportionality constant K3 which control the slope of the function controls the response time of the pacing system -to changes in stroke volume of the patient.
Since it is desirable to have a fast ac~ing sys-tem and it is desirable to have a large value of K3. In canine work values for -the proportionality constan-t have varied from 156 bpm/L to 1250 bpm/L with a value of 600 bpm/L proving suitable for canines with induced hear-t block.
The calcula-tecl value of the chancJe in the desirecl heart rate computed in func-tional block 106 is added to -the existing value of the heart ra-te and if this new value falls within the limits prescribed by functional block 1]0 it is delivered to the pulse generator -to con-trol the pacing of the patients' heart.
It is desirable -to have the maximum and minimum heart ra-tes for the system physician prescribecl.

Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
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 para-meter 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 measure-ment 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.
2. 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;
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.
3. A cardiac pacer for the therapeutic stimulation of a heart comprising:
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 measureing 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 measure-ment 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.
4. The cardiac pacer of claim 1 or claim 2 or claim 3 wherein said computation and control means further includes:
means for determining said stroke volume set point value from said heart rate value.
CA000457692A 1983-06-30 1984-06-28 Stroke volume controlled pacer Expired CA1243361A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US509,573 1983-06-30
US06/509,573 US4535774A (en) 1983-06-30 1983-06-30 Stroke volume controlled pacer

Publications (1)

Publication Number Publication Date
CA1243361A true CA1243361A (en) 1988-10-18

Family

ID=24027220

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000457692A Expired CA1243361A (en) 1983-06-30 1984-06-28 Stroke volume controlled pacer

Country Status (5)

Country Link
US (1) US4535774A (en)
EP (1) EP0140472B1 (en)
JP (1) JPS6034462A (en)
CA (1) CA1243361A (en)
DE (1) DE3479709D1 (en)

Families Citing this family (129)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5190035A (en) * 1981-06-18 1993-03-02 Cardiac Pacemakers, Inc. Biomedical method and apparatus for controlling the administration of therapy to a patient in response to changes in physiological demand
US4782836A (en) * 1984-05-24 1988-11-08 Intermedics, Inc. Rate adaptive cardiac pacemaker responsive to patient activity and temperature
DE3419439C1 (en) * 1984-05-24 1985-11-21 Eckhard Dr. 8000 München Alt Frequency-dependent pacemaker depending on the load
US4708143A (en) * 1984-07-19 1987-11-24 Cordis Leads Inc. Method for controlling pacing of a heart in response to changes in stroke volume
US4802481A (en) * 1984-07-19 1989-02-07 Cordis Leads, Inc. Apparatus for controlling pacing of a heart in response to changes in stroke volume
US4860751A (en) * 1985-02-04 1989-08-29 Cordis Corporation Activity sensor for pacemaker control
US4716887A (en) * 1985-04-11 1988-01-05 Telectronics N.V. Apparatus and method for adjusting heart/pacer rate relative to cardiac pCO2 to obtain a required cardiac output
US4719921A (en) * 1985-08-28 1988-01-19 Raul Chirife Cardiac pacemaker adaptive to physiological requirements
US4674518A (en) * 1985-09-06 1987-06-23 Cardiac Pacemakers, Inc. Method and apparatus for measuring ventricular volume
DE3689354D1 (en) * 1985-09-17 1994-01-13 Biotronik Mess & Therapieg Pacemaker.
DE3689347D1 (en) * 1985-09-17 1994-01-13 Biotronik Mess & Therapieg Pacemaker.
DE3650261D1 (en) * 1985-09-17 1995-04-13 Biotronik Mess & Therapieg Pacemaker.
EP0215731B1 (en) * 1985-09-17 1992-12-30 BIOTRONIK Mess- und Therapiegeräte GmbH & Co Ingenieurbüro Berlin Heart stimulator
EP0215729B1 (en) * 1985-09-17 1992-12-02 BIOTRONIK Mess- und Therapiegeräte GmbH & Co Ingenieurbüro Berlin Heart stimulator
EP0215730B1 (en) * 1985-09-17 1993-06-16 BIOTRONIK Mess- und Therapiegeräte GmbH & Co Ingenieurbüro Berlin Heart stimulator
DE3533597A1 (en) * 1985-09-18 1987-04-16 Biotronik Mess & Therapieg HEART PACEMAKER
US4936304A (en) * 1985-10-07 1990-06-26 Thomas Jefferson University Pacing system and method for cardiac pacing as a function of determined myocardial contractility
US4702253A (en) * 1985-10-15 1987-10-27 Telectronics N.V. Metabolic-demand pacemaker and method of using the same to determine minute volume
US4770177A (en) * 1986-02-18 1988-09-13 Telectronics N.V. Apparatus and method for adjusting heart/pacer relative to changes in venous diameter during exercise to obtain a required cardiac output.
US4776338A (en) * 1986-06-16 1988-10-11 Siemens Aktiengesellschaft Cardiac pacer for pacing a human heart and pacing method
DE3775281D1 (en) * 1986-06-16 1992-01-30 Siemens Ag DEVICE FOR CONTROLLING A HEART PACER BY MEANS OF IMPEDANCE ON BODY TISSUES.
DE3631155A1 (en) * 1986-09-12 1988-03-24 Alt Eckhard FREQUENCY VARIABLE HEART PACEMAKER WITH STRESS-ADEQUATE FREQUENCY BEHAVIOR
US4827933A (en) * 1986-10-30 1989-05-09 Telectronics N.V. Apparatus and method for adjusting heart/pacer rate relative to cardiac pO2 obtain a required cardiac output
DE3750983T2 (en) * 1987-05-01 1995-05-18 Cardiac Pacemakers Inc Biomedical method and device for the controlled administration of treatment for a patient in relation to changes in physiological needs.
JPS6464671A (en) * 1987-05-28 1989-03-10 Cardiac Pacemakers Inc Cardiac pacemaker and generating method for variable heart rate
US4858611A (en) * 1987-06-03 1989-08-22 Dimed, Inc. Sensing system and method for sensing minute ventilation
SE8702523D0 (en) * 1987-06-17 1987-06-17 Siemens Elema Ab RATE RESPONSIVE PACEMAKER
US4773401A (en) * 1987-08-21 1988-09-27 Cardiac Pacemakers, Inc. Physiologic control of pacemaker rate using pre-ejection interval as the controlling parameter
DE3732640C1 (en) * 1987-09-28 1989-05-18 Alt Eckhard Medical device for determining physiological functional parameters
US4905696A (en) * 1987-10-07 1990-03-06 Siemens Aktiengesellschaft Method and apparatus for P-synchronously stimulating the heart of a patient
US4827934A (en) * 1987-10-27 1989-05-09 Siemens-Pacesetter, Inc. Sensing margin detectors for implantable electromedical devices
GB2214813A (en) * 1988-01-14 1989-09-13 Stuart Charles Webb Rate-responsive pacemaker
US4901725A (en) * 1988-01-29 1990-02-20 Telectronics N.V. Minute volume rate-responsive pacemaker
EP0331309B1 (en) * 1988-02-17 1996-11-13 Stuart Charles Webb Rate-responsive pacemaker
EP0334675B2 (en) 1988-03-25 2002-03-27 Telectronics N.V. Rate-responsive pacemaker with closed-loop control
US5318595A (en) * 1989-09-25 1994-06-07 Ferek Petric Bozidar Pacing method and system for blood flow velocity measurement and regulation of heart stimulating signals based on blood flow velocity
US5031616A (en) * 1989-12-07 1991-07-16 Siemens-Pacesetter, Inc. Implantable stimulation device having means for self-regulating curent drain usage at battery depletion
US5052388A (en) * 1989-12-22 1991-10-01 Medtronic, Inc. Method and apparatus for implementing activity sensing in a pulse generator
US5058583A (en) * 1990-07-13 1991-10-22 Geddes Leslie A Multiple monopolar system and method of measuring stroke volume of the heart
US5134997A (en) * 1990-08-14 1992-08-04 Medtronic, Inc. Rate responsive pacemaker and pacing method
US5271392A (en) * 1990-08-24 1993-12-21 Siemens-Elema Ab Method and apparatus for administering cardiac electrotherapy dependent on mechanical and electrical cardiac activity
DE69114948D1 (en) * 1990-08-24 1996-01-11 Ferek Petric Bozidar Cardiac irritation system with measurement of the heart contraction force.
EP0474957A3 (en) * 1990-09-11 1992-06-24 Bozidar Ferek-Petric Ultrasonic doppler synchronized cardiac electrotherapy device
US5113862A (en) * 1990-09-25 1992-05-19 Siemens Pacesetter, Inc. Blood oxygen sensor having leakage compensation
WO1992005836A1 (en) * 1990-10-04 1992-04-16 Siemens-Elema Ab Arrangement, in particular heart pacemaker, for recording a heart activity measurement parameter
US5119813A (en) * 1990-11-05 1992-06-09 Leonard Bloom Mixed venous oxygen saturation responsive system for and method of treating a malfunctioning heart
FR2671013B1 (en) * 1990-12-27 1996-09-13 Ela Medical Sa HEART STIMULATOR WITH SERVO STIMULATION FREQUENCY.
US5188106A (en) * 1991-03-08 1993-02-23 Telectronics Pacing Systems, Inc. Method and apparatus for chronically monitoring the hemodynamic state of a patient using doppler ultrasound
DE4111505C2 (en) * 1991-04-09 1997-04-17 Pacesetter Ab Arrangement for determining a physiological parameter from a cardiac information signal
SE9101276D0 (en) * 1991-04-26 1991-04-26 Siemens Elema Ab IMPLANT MEDICAL DEVICE
US5154171A (en) * 1991-06-15 1992-10-13 Raul Chirife Rate adaptive pacemaker controlled by ejection fraction
WO1993020890A1 (en) * 1992-04-10 1993-10-28 Random Technologies, Inc. Pacemaker with time domain reflectometer
US5197467A (en) * 1992-06-22 1993-03-30 Telectronics Pacing Systems, Inc. Multiple parameter rate-responsive cardiac stimulation apparatus
JPH07504597A (en) * 1992-06-30 1995-05-25 メドトロニック インコーポレーテッド Electrical medical stimulators and electrical stimulation methods
DE4231601A1 (en) * 1992-09-17 1994-03-24 Biotronik Mess & Therapieg Arrangement for controlling a pacemaker
DE4231602B4 (en) * 1992-09-17 2004-11-04 Biotronik Meß- und Therapiegeräte GmbH & Co. Ingenieurbüro Berlin Circuit for measuring the impedance in the heart
SE9202937D0 (en) * 1992-10-07 1992-10-07 Siemens Elema Ab FREQUENCY ADAPTIVE HEART STIMULATOR
SE9302358D0 (en) * 1993-07-07 1993-07-07 Siemens-Elema Ab HJAERTSTIMULATOR
US5411531A (en) * 1993-09-23 1995-05-02 Medtronic, Inc. Method and apparatus for control of A-V interval
HRP931478A2 (en) * 1993-12-06 1995-12-31 Ferek Petri Bo Idar An apparatus for cardial electrotherapy containing transmission line uring cardial contractions
US5618245A (en) * 1994-02-04 1997-04-08 True Fitness Technology, Inc. Fitness apparatus with heart rate control system and method of operation
US5462504A (en) * 1994-02-04 1995-10-31 True Fitness Technology Inc. Fitness apparatus with heart rate control system and method of operation
US6033344A (en) * 1994-02-04 2000-03-07 True Fitness Technology, Inc. Fitness apparatus with heart rate control system and method of operation
US5824029A (en) * 1994-04-28 1998-10-20 Medtronic, Inc. Implantable medical system for performing transthoracic impedance measurements associated with cardiac function
US5713933A (en) * 1994-11-30 1998-02-03 Medtronic, Inc. Method and apparatus for automatic pacing threshold determination
DE19609382A1 (en) * 1996-03-04 1997-09-11 Biotronik Mess & Therapieg Activity-controlled pacemaker
SE9603574D0 (en) * 1996-09-30 1996-09-30 Pacesetter Ab Heart stimulation device
WO1998019594A1 (en) * 1996-11-04 1998-05-14 The Johns-Hopkins University Assessing cardiac contractility and cardiovascular interaction
US5782884A (en) * 1996-11-05 1998-07-21 Sulzer Intermedics Inc. Rate responsive cardiac pacemaker with peak impedance detection for rate control
SE9701121D0 (en) * 1997-03-26 1997-03-26 Pacesetter Ab Implantable heart stimulator
US6314322B1 (en) 1998-03-02 2001-11-06 Abiomed, Inc. System and method for treating dilated cardiomyopathy using end diastolic volume (EDV) sensing
US6119040A (en) * 1998-06-29 2000-09-12 Chirife; Raul Cardiac pacemaker upper rate limit control
SE9901194D0 (en) * 1999-03-31 1999-03-31 Pacesetter Ab A rate adaptive pacemaker
US6317626B1 (en) 1999-11-03 2001-11-13 Medtronic, Inc. Method and apparatus for monitoring heart rate
US8298150B2 (en) * 2000-01-11 2012-10-30 Cedars-Sinai Medical Center Hemodynamic waveform-based diagnosis and treatment
EP1142608A2 (en) 2000-04-05 2001-10-10 Pacesetter, Inc. System and method for prevention of recurrent vasovagal syncope using cardiac pacing
US6647295B2 (en) 2000-05-15 2003-11-11 Pacesetter, Inc. Implantable cardiac stimulation device with detection and therapy for patients with vasovagal syncope
US6625492B2 (en) 2000-05-15 2003-09-23 Pacesetter, Inc. Implantable cardiac stimulation device with detection and therapy for patients with vasovagal syncope
SE0001836D0 (en) * 2000-05-18 2000-05-18 Inovacor Ab Computer based system
US6922587B2 (en) * 2002-06-26 2005-07-26 Pacesetter, Inc. System and method for tracking progression of left ventricular dysfunction using implantable cardiac stimulation device
US7657482B1 (en) * 2002-07-15 2010-02-02 Paymentech, L.P. System and apparatus for transaction fraud processing
SE0202288D0 (en) * 2002-07-22 2002-07-22 St Jude Medical A heart stimulator
FR2860980B1 (en) * 2003-10-16 2005-12-30 Ela Medical Sa ACTIVE IMPLANTABLE MEDICAL DEVICE COMPRISING MEANS FOR ADJUSTING THE MAXIMUM FREQUENCY OF VENTRICULAR STIMULATION BASED ON THE HEMODYNAMIC STATUS OF THE PATIENT
US7220230B2 (en) * 2003-12-05 2007-05-22 Edwards Lifesciences Corporation Pressure-based system and method for determining cardiac stroke volume
US7452333B2 (en) * 2003-12-05 2008-11-18 Edwards Lifesciences Corporation Arterial pressure-based, automatic determination of a cardiovascular parameter
US7422562B2 (en) * 2003-12-05 2008-09-09 Edwards Lifesciences Real-time measurement of ventricular stroke volume variations by continuous arterial pulse contour analysis
US7239915B2 (en) * 2003-12-16 2007-07-03 Medtronic, Inc. Hemodynamic optimization system for biventricular implants
US7794404B1 (en) 2006-03-31 2010-09-14 Pacesetter, Inc System and method for estimating cardiac pressure using parameters derived from impedance signals detected by an implantable medical device
US8600497B1 (en) 2006-03-31 2013-12-03 Pacesetter, Inc. Systems and methods to monitor and treat heart failure conditions
US8712519B1 (en) 2006-03-31 2014-04-29 Pacesetter, Inc. Closed-loop adaptive adjustment of pacing therapy based on cardiogenic impedance signals detected by an implantable medical device
US7569019B2 (en) * 2006-06-16 2009-08-04 Frank Bour Analysis and use of cardiographic bioimpedance measurements
US8406879B2 (en) 2006-12-20 2013-03-26 Cardiac Pacemakers, Inc. Rate adaptive cardiac pacing systems and methods
US8504152B2 (en) 2007-04-04 2013-08-06 Pacesetter, Inc. System and method for estimating cardiac pressure based on cardiac electrical conduction delays using an implantable medical device
US8208999B2 (en) 2007-04-04 2012-06-26 Pacesetter, Inc. System and method for estimating electrical conduction delays from immittance values measured using an implantable medical device
DE102007028683A1 (en) 2007-06-21 2008-12-24 Maschinenfabrik Wifag Roller changing device with trolley system
US20090270739A1 (en) * 2008-01-30 2009-10-29 Edwards Lifesciences Corporation Real-time detection of vascular conditions of a subject using arterial pressure waveform analysis
WO2009135075A1 (en) 2008-04-30 2009-11-05 Medtronic, Inc. Techniques for placing medical leads for electrical stimulation of nerve tissue
US8535215B2 (en) * 2008-08-29 2013-09-17 St. Jude Medical Ab Implantable heart monitoring device and method
US9775987B2 (en) 2008-10-31 2017-10-03 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US9597505B2 (en) * 2008-10-31 2017-03-21 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US8473057B2 (en) * 2008-10-31 2013-06-25 Medtronic, Inc. Shunt-current reduction housing for an implantable therapy system
US8611996B2 (en) 2008-10-31 2013-12-17 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US9192769B2 (en) * 2008-10-31 2015-11-24 Medtronic, Inc. Shunt-current reduction techniques for an implantable therapy system
WO2010051500A1 (en) * 2008-10-31 2010-05-06 Medtronic, Inc. Therapy system including cardiac rhythm therapy and neurostimulation capabilities
US8452394B2 (en) 2008-10-31 2013-05-28 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US8498698B2 (en) 2008-10-31 2013-07-30 Medtronic, Inc. Isolation of sensing and stimulation circuitry
US8532779B2 (en) * 2008-10-31 2013-09-10 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US8774918B2 (en) * 2008-10-31 2014-07-08 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US8260412B2 (en) 2008-10-31 2012-09-04 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US8005539B2 (en) * 2008-10-31 2011-08-23 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US8688210B2 (en) * 2008-10-31 2014-04-01 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US8560060B2 (en) 2008-10-31 2013-10-15 Medtronic, Inc. Isolation of sensing and stimulation circuitry
US8249708B2 (en) * 2008-10-31 2012-08-21 Medtronic, Inc. Implantable medical device crosstalk evaluation and mitigation
US8241221B2 (en) * 2009-02-05 2012-08-14 Pacesetter, Inc. Systems and methods for use with an implantable medical device for detecting stroke based on electrocardiac signals
US8467864B2 (en) * 2010-03-11 2013-06-18 Pacesetter, Inc. Systems and methods for use by an implantable medical device for detecting and discriminating stroke and cardiac ischemia using electrocardiac signals and hemodynamic parameters
US8406868B2 (en) 2010-04-29 2013-03-26 Medtronic, Inc. Therapy using perturbation and effect of physiological systems
US8620425B2 (en) 2010-04-29 2013-12-31 Medtronic, Inc. Nerve signal differentiation in cardiac therapy
US8639327B2 (en) 2010-04-29 2014-01-28 Medtronic, Inc. Nerve signal differentiation in cardiac therapy
US8781583B2 (en) 2011-01-19 2014-07-15 Medtronic, Inc. Vagal stimulation
US8781582B2 (en) 2011-01-19 2014-07-15 Medtronic, Inc. Vagal stimulation
US8725259B2 (en) 2011-01-19 2014-05-13 Medtronic, Inc. Vagal stimulation
US8718763B2 (en) 2011-01-19 2014-05-06 Medtronic, Inc. Vagal stimulation
US8706223B2 (en) 2011-01-19 2014-04-22 Medtronic, Inc. Preventative vagal stimulation
US8989852B2 (en) 2011-08-10 2015-03-24 Pacesetter, Inc. Systems and methods for use by implantable medical devices for detecting and discriminating stroke and cardiac ischemia using electrocardiac signals
WO2013029124A1 (en) 2011-09-02 2013-03-07 Adelina Pancheva Zero blood flow sensitive heart stimulator
US8768461B2 (en) 2011-09-06 2014-07-01 Pacesetter, Inc. Systems and methods for controlling paired pacing interpulse intervals to reduce contractility disequilibrium using an implantable medical device
US9878080B2 (en) 2014-01-14 2018-01-30 CardioFlow Technologies, LLC Apparatus and methods for optimizing intra cardiac filling pressures, heart rate, and cardiac output
WO2016196412A1 (en) 2015-05-30 2016-12-08 CardioFlow Technologies, LLC Apparatus and methods for optimizing intra-cardiac filling pressures through controlled regurgitation
US10918858B2 (en) * 2016-07-20 2021-02-16 Cardiac Pacemakers, Inc. Cardiac volume sensing via an implantable medical device in support of cardiac resynchronization therapy

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4303075A (en) * 1980-02-11 1981-12-01 Mieczyslaw Mirowski Method and apparatus for maximizing stroke volume through atrioventricular pacing using implanted cardioverter/pacer
DE3107128C2 (en) * 1981-02-26 1984-07-05 Heinze, Roland, Dipl.-Ing., 8000 München Control circuit for adapting the stimulation frequency of a cardiac pacemaker to the load on a patient
US4467807A (en) * 1981-11-23 1984-08-28 Medtronic, Inc. Rate adaptive demand pacemaker
US4436092A (en) * 1982-05-19 1984-03-13 Purdue Research Foundation Exercise responsive cardiac pacemaker

Also Published As

Publication number Publication date
JPH0368708B2 (en) 1991-10-29
EP0140472A1 (en) 1985-05-08
DE3479709D1 (en) 1989-10-19
US4535774A (en) 1985-08-20
EP0140472B1 (en) 1989-09-13
JPS6034462A (en) 1985-02-22

Similar Documents

Publication Publication Date Title
CA1243361A (en) Stroke volume controlled pacer
US5549650A (en) System and method for providing hemodynamically optimal pacing therapy
US4773401A (en) Physiologic control of pacemaker rate using pre-ejection interval as the controlling parameter
US6580946B2 (en) Pressure-modulated rate-responsive cardiac pacing
EP0541338B1 (en) Implantable cardiac function monitor and stimulator for diagnosis and therapy delivery
US7024244B2 (en) Estimation of stroke volume cardiac output using an intracardiac pressure sensor
EP0615770B1 (en) Apparatus for managing and monitoring cardiac rhythm using active time as the controlling parameter
Schaldach et al. Intracardiac impedance to determine sympathetic activity in rate responsive pacing
US8032214B2 (en) Method and apparatus for optimizing ventricular synchrony during DDD resynchronization therapy using adjustable atrio-ventricular delays
US7184835B2 (en) Method and apparatus for adjustable AVD programming using a table
US7974695B2 (en) Method and apparatus for optimizing stroke volume during DDD resynchronization therapy using adjustable atrio-ventricular delays
US4856523A (en) Rate-responsive pacemaker with automatic mode switching and/or variable hysteresis rate
EP1499386B1 (en) Atrioventricular delay adjustment
US6233486B1 (en) Ischemia detector and heart stimulator provided with such an ischemia detector
US8700154B2 (en) Pressure-modulated energy level for pacing pulses
US5861009A (en) Implantable cardiac stimulator with rate-adaptive T-wave detection
JP2002501805A (en) Non-invasive respiratory circulation monitor with synchronous bioimpedance sensing
US6754532B1 (en) Coronary sinus flow regulated pacing
US5500005A (en) Activity responsive heart stimulator dependent on return blood flow to the heart
JP2788163B2 (en) Method and apparatus for managing and monitoring cardiac rhythm utilizing cardiac activity time as a control parameter

Legal Events

Date Code Title Description
MKEX Expiry