Patent US3877438A successfully refreshed from Google Patents.
US3877438A
Expired / Lapsed
US
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Pacer with self-adjusting output
Assignee: American Optical Corp
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Filing: 1974-02-07
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Granted: 1975-04-15
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Expires: 1994-02-07
Abstract
Abstract There is disclosed an implantable pacer, the characteristics of whose output pulses change automatically after the pacer has generated a predetermined number of pulses. The pacer includes a charge-dependent resistor whose impedance increases in accordance with the total current flow through it. After a predetermined number of pulses have been generated, the impedance increases relatively abruptly. The increase in impedance controls a decrease in the amplitude and/or decrease in the width of subsequent pulses.
Inventors
- 👤 Robert L Cannon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:07
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/365
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
162 words
A heart pacer comprising electrode means for connection to a patient''s heart, pulser means for generating and applying stimulating pulses to said electrode means, timing means for controlling the geneRation of stimulating pulses by said pulser means in timed sequence, means for measuring the number of stimulating pulses generated by said pulser means, means responsive to said measuring means for controlling said pulser means to change a characteristic of subsequently generated pulses, said measuring means including a coulometer device having a characteristic which is a function of the total current which flowed through it, means for causing a current to flow through said coulometer device whenever said pulser means generates a stimulating pulse, said pulser means comprising two capacitors connected in parallel for furnishing a current pulse to said electrode means, said coulometer device being connected in series with one of said capacitors, and said measuring means including means for allowing a current flow in only one direction through said coulometer device.
Claim 2
Dependent Claim
162 words
A heart pacer comprising electrode means for connection to a patient''s heart, pulser means for generating and applying stimulating pulses to said electrode means, timing means for controlling the geneRation of stimulating pulses by said pulser means in timed sequence, means for measuring the number of stimulating pulses generated by said pulser means, means responsive to said measuring means for controlling said pulser means to change a characteristic of subsequently generated pulses, said measuring means including a coulometer device having a characteristic which is a function of the total current which flowed through it, means for causing a current to flow through said coulometer device whenever said pulser means generates a stimulating pulse, said pulser means comprising two capacitors connected in parallel for furnishing a current pulse to said electrode means, said coulometer device being connected in series with one of said capacitors, and said measuring means including means for allowing a current flow in only one direction through said coulometer device.
Claim 3
Dependent Claim
33 words
A heart pacer in accordance with claim 1 wherein said coulometer device includes means for inhibiting current by said one capacitor to said electrode means after a predetermined total current has flowed therethrough.
Claim 4
Dependent Claim
49 words
A heart pacer in accordance with claim 2 wherein said controlling means includes means for causing the amplitude of the stimulating pulses generated by said pulser means to decrease as the total number of stimulating pulses generated by said pulser means increases, until the amplitude reaches a predetermined magnitude.
Claim 5
Dependent Claim
41 words
A heart pacer in accordance with claim 3 wherein said controlling means includes further means for decreasing the width of the stimulating pulses generated by said pulser means as the total number of stimulating pulses generated by said pulser means increases.
Claim 6
Dependent Claim
49 words
A heart pacer in accordance with claim 1 wherein said controlling means includes means for causing the amplitude of the stimulating pulses generated by said pulser means to decrease as the total number of stimulating pulses generated by said pulser means increases, until the amplitude reaches a predetermined magnitude.
Claim 7
Dependent Claim
41 words
A heart pacer in accordance with claim 5 wherein said controlling means includes further means for decreasing the width of the stimulating pulses generated by said pulser means as the total number of stimulating pulses generated by said pulser means increases.
Claim 8
Dependent Claim
41 words
A heart pacer in accordance with claim 1 wherein said controlling means includes further means for decreasing the width of the stimulating pulses generated by said pulser means as the total number of stimulating pulses generated by said pulser means increases.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |