Patent US4903699A successfully refreshed from Google Patents.
US4903699A
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Implantable cardiac stimulator with automatic gain control
Assignee: Intermedics Inc
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Filing: 1988-06-07
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Granted: 1990-02-27
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Expires: 2008-06-07
Abstract
Abstract An implantable cardiac stimulator for detecting and treating bradycardias includes a sense amplifier responsive to sensed cardiac signals for detecting cardiac activity. The sense amplifier includes an automatic gain control amplifier, a filter and quad comparator having a pair of signal channels to establish sensing thresholds, margins and signal gain. The sense amplifier has a feedback loop containing a microprocessor which implements preselected algorithms in conjunction with the outputs of the quad comparator to variably adjust the amplifier gain and to programmably control the sensing margin.
Inventors
- 👤 Ross G. Baker, Jr.
- 👤 Edward A. Haluska
- 👤 Joseph W. Vandgriff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:42
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/37; A61N1/3702; A61N1/3704; A61N1/3706
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
135 words
An implantable cardiac stimulator for detecting cardiac cycles by analyzing electrical signals produced by the heart, comprising: means for detecting electrical signals produced by the heart; and amplifier means responsive to the detected signals and having dual signal paths for said detected signals, one of said paths having a feedback loop with means for automatically adjusting the gain of the amplifier means, the other said signal paths enables the determination of a sensing level, said means for automatically controlling the gain including an algorithm controlling gain requiring a ratio of greater than 1 to 1, said algorithm controlling gain requiring sensing of two lows in a row to increase gain and sensing one high to decrease gain whereby the gain and threshold relationships between said dual signal paths maybe altered to produce variable sensing margins.
Claim 2
Dependent Claim
135 words
An implantable cardiac stimulator for detecting cardiac cycles by analyzing electrical signals produced by the heart, comprising: means for detecting electrical signals produced by the heart; and amplifier means responsive to the detected signals and having dual signal paths for said detected signals, one of said paths having a feedback loop with means for automatically adjusting the gain of the amplifier means, the other said signal paths enables the determination of a sensing level, said means for automatically controlling the gain including an algorithm controlling gain requiring a ratio of greater than 1 to 1, said algorithm controlling gain requiring sensing of two lows in a row to increase gain and sensing one high to decrease gain whereby the gain and threshold relationships between said dual signal paths maybe altered to produce variable sensing margins.
Claim 3
Dependent Claim
13 words
An implantable cardiac stimulator according to claim 1, wherein said ratio is 2:1.
Claim 4
Dependent Claim
32 words
An implantable cardiac stimulator according to claim 1, wherein the algorithm controlling gain avoids over-amplification when no valid signal is present, for purpose of noise immunity, and appropriate sensing when signals return.
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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) | 1993-02-26 | 1993-08-28 | 1994-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-26 | 1997-08-28 | 1998-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-26 | 2001-08-28 | 2002-02-27 | $7700.00 | Window Closed / Lapsed |