EP0634192A1
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EP
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Heart stimulator
Assignee: St Jude Medical AB
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Filing: 1994-06-20
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Granted: —
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Expires: 2014-06-20
Abstract
Abstract A heart stimulator (2) is described which emits stimulation pulses to a heart, said heart stimulator (2) comprises a function unit (14, 16) for regulating a variable function in the heart stimulator (2), a measurement device (32) for measuring the return flow of blood to the heart and a control device (26, 28, 30) for controlling the function unit's regulation of the function on the basis of changes in the return flow of blood. A particularly advantageous version is achieved when the function unit (14, 16) comprises a pulse generator (14, 16) which generates and emits the stimulation pulses at a variable interval, the heart stimulator then becoming rate-adaptive and optimizing cardiac output. In this manner, heart rate is regulated on the basis of a variable directly related to the body's oxygenation needs.
Inventors
- 👤 Kurt Högnelid
- 👤 Hans Strandberg
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 20:53
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/37; A61N1/3702
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
121 words
A heart stimulator (2; 54) comprising at least one function unit (14, 16; 74, 76, 86, 88) for regulating a variable function in the heart stimulator (2; 54), a measurement device (32; 98) for measuring a physiological variable and a control device (26, 28, 30; 100) for controlling the function unit's (14, 16; 74, 76, 86, 88) regulation of the function on the basis of the physiological variable, characterized in that the measurement device (32; 98) measures the return flow of blood to the heart (4; 56), and the control device (26, 28, 30; 100) controls the function unit's (14, 16; 74, 76, 86, 88) regulation of the function on the basis of changes in the measured return flow of blood.
Claim 2
Dependent Claim
64 words
A heart stimulator according to claim 1 , characterized in that the measurement device (32; 98) is connected to a first electrode (6; 70) and a second electrode (10; 66), and a voltage supply (44; 106) is connected to maintain a constant voltage across the electrodes (6, 10; 70, 66), whereby current from the measurement device (32) corresponds to the return flow of blood.
Claim 3
Dependent Claim
40 words
A heart stimulator according to claim 1 or 2, characterized in that the function unit (14, 16; 74, 86, 88) comprises a pulse generator for generating and emitting stimulation pulses to the heart (4, 56) at a variable stimulation interval.
Claim 4
Dependent Claim
67 words
A heart stimulator according to any of the above claims, characterized by an averager (104) for determining the average value for the return flow of blood to the heart as measured by the measurement device (32), the control device (26, 28, 30) then controls the function unit's (14, 16; 74, 76, 86, 88) regulation of the function on the basis of changes in the determined average value.
Claim 5
Dependent Claim
70 words
A heart stimulator according to claim 4, characterized in that the averager (104) comprises a means for sampling a predetermined number of measured values for the return flow of blood in each heart cycle, and the averager (104) determines the average value for the return flow of blood in a predetermined preceding time interval or a predetermined number of preceding heart cycles on the basis of the sampled measurement values.
Claim 6
Dependent Claim
60 words
A heart stimulator according to claim 4, characterized in that the averager (104) comprises a means for determining the maximum value and minimum value for the return flow of blood in each heart cycle, and the averager (104) determines the average value for a predetermined number of preceding heart cycles on the basis of the determined maximum and minimum values.
Claim 7
Dependent Claim
42 words
A heart stimulator according to claim 4, characterized in that the averager (104) determines the average value for the continuous measurement signal for the return flow of blood for a predetermined preceding time interval or a predetermined number of preceding heart cycles.
Claim 8
Dependent Claim
93 words
A heart stimulator according to any of the above claims, characterized in that the heart stimulator further comprises a first tip electrode (58), placed in an atrium of the heart (56), and a second tip electrode (62) placed in a ventricle the a heart (56), in order to deliver atrial and ventricular stimulation pulses respectively to the heart (56), the function unit comprises a timer for regulating a variable time interval between delivery of atrial stimulation pulses and delivery of ventricular stimulation pulses and the control device (100) controls the timer's timing interval.
Claim 9
Dependent Claim
60 words
A heart stimulator according to any of the above claims, characterized by a means for monitoring changes in the return flow of blood measured by the measurement device, any momentary change in blood flow exceeding a predetermined threshold value then being interpreted as abnormal and ignored by the control device during control of the function unit's regulation of the function.
Claim 10
Dependent Claim
45 words
A heart stimulator according to any of the above claims, characterized by at least one additional measurement device for measuring at least one additional physiological variable, whereby the control device controls the function unit's regulation of function on the basis of the additional physiological variable.
Claim 11
Dependent Claim
36 words
A heart stimulator according to any of the above claims, characterized by a memory unit (30) for storing values representing the return flow of blood over a predetermined period of time, preferably at least 24 hours.
Claim 12
Dependent Claim
28 words
A heart stimulator according to claim 11, characterized in that the memory unit (30) stores the minimum value and the maximum value for the predetermined period of time.
Claim 13
Dependent Claim
36 words
A heart stimulator according to claim 11 or 12 in combination with claim 7, characterized in that the memory unit (30) is devised to also store values representing stimulation intervals for the predetermined period of time.
Claim 14
Dependent Claim
70 words
A heart stimulator according to claim 13, characterized in that the control device (26, 28, 30) calculates, on the basis of the stored values representing the return flow of blood and stimulation intervals, the way in which the return flow of blood varies with changes in the stimulation interval and, on the basis thereof, how the stimulation interval should be changed according to changes in the return flow of blood.
Claim 15
Dependent Claim
42 words
A heart stimulator according to any of the above claims, characterized in that the control device (26, 28, 30) controls the stimulation interval so it can only change within a predetermined interval between a minimum stimulation interval and a maximum stimulation interval.
References Cited (Backward Citations)
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