US4790318A
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US
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Cardiac pacer for pacing a human heart
Assignee: Pacesetter AB
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Filing: 1986-06-16
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Granted: 1988-12-13
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Expires: 2006-06-16
Abstract
Abstract A cardiac pacer which generates pacing pulses at a predetermined pacing rate, includes a device for generating an alternating signal which is unable to pace the heart. The pacing pulses and the alternating signal are transmitted together to the heart. The alternating signal after transmittal to the heart is measured and processed such that a respiratory signal is obtained. The predetermined pacing rate is then varied dependent on the respiratory signal.
Inventors
- 👤 Hakan Elmqvist
- 👤 Anders Lekholm
- 👤 Sven-Erik Hedberg
- 👤 David C. Amundson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:49
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: 21
Claim 1
Independent Claim
146 words
A cardiac pacer for pacing a human heart in a patient comprising (a) means for generating pacing pulses at a predetermined pacing rate; (b) means for generating an alternating signal having an amplitude less than that necessary to pace the heart; (c) means connected to said means for generating pacing pulses and to said means for generating an alternating signal for transmitting the pacing pulses together with the alternating signal directly to the heart along a common transmission path wherein said alternating signal is modified at least in part by the respiratory activity of said patient, and for receiving said modified alternating signal from said heart, (d) means connected to said means for transmitting and receiving for processing the alternating signal after transmittal to the heart for obtaining a respiratory signal therefrom; and (e) means for varying the predetermined pacing rate dependent on the respiratory signal.
Claim 2
Dependent Claim
146 words
A cardiac pacer for pacing a human heart in a patient comprising (a) means for generating pacing pulses at a predetermined pacing rate; (b) means for generating an alternating signal having an amplitude less than that necessary to pace the heart; (c) means connected to said means for generating pacing pulses and to said means for generating an alternating signal for transmitting the pacing pulses together with the alternating signal directly to the heart along a common transmission path wherein said alternating signal is modified at least in part by the respiratory activity of said patient, and for receiving said modified alternating signal from said heart, (d) means connected to said means for transmitting and receiving for processing the alternating signal after transmittal to the heart for obtaining a respiratory signal therefrom; and (e) means for varying the predetermined pacing rate dependent on the respiratory signal.
Claim 3
Dependent Claim
41 words
A cardiac pacer as claimed in claim 1, wherein said alternating signal generating means generates an alternating current having an amplitude, said amplitude being dependent on the frequency of said alternating signal lying substantially below the fibrillation threshold of the heart.
Claim 4
Dependent Claim
47 words
A cardiac pacer as claimed in claim 2, wherein said alternating signal generating means generates an alternating current having an amplitude, said amplitude being dependent on the frequency of said alternating signal and lying substantially below the fibrillation threshold of the heart at frequencies above 150 Hz.
Claim 5
Dependent Claim
28 words
A cardiac pacer as claimed in claim 3, wherein said alternating signal generating means generates an alternating current in the frequency range of 1 kHz to 10 kHz.
Claim 6
Dependent Claim
14 words
A cardiac pacer as claimed in claim 4, wherein said frequency is 4 kHz.
Claim 7
Dependent Claim
27 words
A cardiac pacer as claimed in claim 4, wherein said alternating signal generating means generates an alternating current having an amplitude which is smaller than 10 μA.
Claim 8
Dependent Claim
17 words
A cardiac pacer as claimed in claim 5, wherein said alternating current is smaller than 2 μA.
Claim 9
Dependent Claim
27 words
A cardiac pacer as claimed in claim 1, wherein said means for processing the alternating signal includes a demodulator for the alternating signal received from said heart.
Claim 10
Dependent Claim
72 words
A cardiac pacer as claimed in claim 1, wherein said means for processing the alternating signal includes means for non-linearly amplifying the respiratory signal such that signal portions having higher amplitudes are more amplified than signal portions having lower amplitudes, means for integrating the non-linearly amplified respiratory signal over a period of time, and wherein said means for varying the predetermined pacing rate varies said pacing rate dependent on the integrated signal.
Claim 11
Dependent Claim
17 words
A cardiac pacer as claimed in claim 9, wherein said period of time is in the range
Claim 12
Dependent Claim
37 words
A cardiac pacer as claimed in claim 1, wherein said means for processing the alternating signal further includes a voltage to pulse rate converter for the integrated signal connected to an output of said means for integrating.
Claim 13
Dependent Claim
113 words
A cardiac pacer as claimed in claim 11, wherein said means for varying the predetermined pacing rate comprises an analog signal to digital control word converter for the output signal of the voltage to pulse rate converter, a time base register for the output signal of the analog signal to digital control word converter, a decremental counter for the output signal of said time base register which is set to higher zero counting speed as the respiration rate increases, and a zero decoder at the output of the decremental counter, said zero decoder being connected with and controlling the pacing pulse generator such that a pacing pulse is generated at each zero count.
Claim 14
Dependent Claim
23 words
A cardiac pacer as claimed in claim 1, wherein said alternating signal generating means is a means for generating a continuous alternating signal.
Claim 15
Dependent Claim
24 words
A cardiac pacer as claimed in claim 1, wherein said alternating signal generating means is a means for generating a duty cycled alternating signal.
Claim 16
Dependent Claim
32 words
A cardiac pacer as claimed in claim 14, wherein the means for generating a duty cycled alternating signal includes means for duty cycling the alternating signal on the cardiac cycle or clock.
Claim 17
Dependent Claim
39 words
A cardiac pacer as claimed in claim 1, wherein said cardiac pacer further comprises a metallic housing forming a passive electrode, and wherein said means for transmitting and receiving includes a single lead terminating in a single active electrode.
Claim 18
Dependent Claim
110 words
A cardiac pacer for pacing a heart in a patient comprising: means for generating pacing pulses at a selecting pacing rate; means for generating an additional non-constant signal having an amplitude less than that necessary to pace said heart; means for transmitting said pacing pulses and said additional signal directly to said heart via a single active electrode, said additional signal being altered at least in part by respiratory activity of said patient, and for receiving the altered signal via said single active electrode; means for processing said altered signal for obtaining a respirator signal therefrom; and means for varying said selected pacing rate in dependence upon said respiratory signal.
Claim 19
Dependent Claim
110 words
A cardiac pacer for pacing a heart in a patient comprising: means for generating pacing pulses at a selecting pacing rate; means for generating an additional non-constant signal having an amplitude less than that necessary to pace said heart; means for transmitting said pacing pulses and said additional signal directly to said heart via a single active electrode, said additional signal being altered at least in part by respiratory activity of said patient, and for receiving the altered signal via said single active electrode; means for processing said altered signal for obtaining a respirator signal therefrom; and means for varying said selected pacing rate in dependence upon said respiratory signal.
Claim 20
Independent Claim
100 words
A method for pacing a heart in a patient comprising: generating pacing pulses at a selected pacing rate; generating an additional non-constant signal having an amplitude less than that necessary to pace said heart; simultaneously transmitting said pacing pulses and said additional signal to said heart via a single active electrode, said additional signal being altered at least in part by respiratory activity of said patient; receiving the altered signal from said heart via said single active electrode; processing said altered signal for obtaining a respiratory signal therefrom; and varying said selected pacing rate in dependents on said respiratory signal.
Claim 21
Independent Claim
100 words
A method for pacing a heart in a patient comprising: generating pacing pulses at a selected pacing rate; generating an additional non-constant signal having an amplitude less than that necessary to pace said heart; simultaneously transmitting said pacing pulses and said additional signal to said heart via a single active electrode, said additional signal being altered at least in part by respiratory activity of said patient; receiving the altered signal from said heart via said single active electrode; processing said altered signal for obtaining a respiratory signal therefrom; and varying said selected pacing rate in dependents on said respiratory signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-13 | 1992-06-13 | 1992-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-13 | 1996-06-13 | 1996-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-13 | 2000-06-13 | 2000-12-13 | $7700.00 | Window Closed / Lapsed |