EP0349130A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Implantable cardiac stimulator with automatic gain control
Assignee: Intermedics Inc
•
Filing: 1989-06-05
•
Granted: —
•
Expires: 2009-06-05
Abstract
Abstract An implantable cardiac stimulator for detecting and treating bradycardias includes a sense amplifier (25) responsive to sensed cardiac signals for detecting cardiac activity. The sense amplifier includes an automatic gain control amplifier (60), a filter (70) and quad comparator (80) having a pair of signal channels to establish sensing thresholds, margins and signal gain. The sense amplifier has a feedback loop containing a microprocessor (68) 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. Vandegriff
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 17:02
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: 20
Claim 1
Independent Claim
59 words
Apparatus for detecting cardiac signals by analyzing electrical signals produced by the heart, comprising: means forming dual signal paths for receiving said electrical signals, one of said signal paths constituting means for determining a sensing point for the signal, and the other of the signal paths constituting feedback loop means for determining signal gain, and thereby, a sensing margin.
Claim 2
Dependent Claim
59 words
Apparatus for detecting cardiac signals by analyzing electrical signals produced by the heart, comprising: means forming dual signal paths for receiving said electrical signals, one of said signal paths constituting means for determining a sensing point for the signal, and the other of the signal paths constituting feedback loop means for determining signal gain, and thereby, a sensing margin.
Claim 3
Dependent Claim
15 words
The invention according to Claim 1, further comprising: a microprocessor in said feedback loop means.
Claim 4
Dependent Claim
15 words
The invention according to Claim 1, further comprising: means for selectively adjusting said sensing margin.
Claim 5
Dependent Claim
31 words
The invention according to Claim 1, in which said feedback loop means includes means for maintaining said sensing margin at a ratio of peak signal size-to-sensing threshold of at least 2-to-1.
Claim 6
Dependent Claim
14 words
The invention according to Claim 4, further including means for programming said sensing means.
Claim 7
Dependent Claim
80 words
Implantable apparatus for detecting cardiac signals, comprising electrode means for sensing electrical activity of a patient's heart, and processing means responsive to the sensed electrical activity for detecting cardiac events, including target means for establishing at least one reference level against which the amplitudes of predetermined sensed events are to be compared, gain control means for controllably varying the sensitivity of the processing means according to the amplitude of the sensed event relative to said at least one reference level.
Claim 8
Dependent Claim
80 words
Implantable apparatus for detecting cardiac signals, comprising electrode means for sensing electrical activity of a patient's heart, and processing means responsive to the sensed electrical activity for detecting cardiac events, including target means for establishing at least one reference level against which the amplitudes of predetermined sensed events are to be compared, gain control means for controllably varying the sensitivity of the processing means according to the amplitude of the sensed event relative to said at least one reference level.
Claim 9
Dependent Claim
49 words
An implantable stimulator for detecting and treating cardiac events, comprising: sensing means for producing electrical signals representative of electrical activity of the heart indicative of rhythmic and arrhythmic contractions thereof, and signal processing means responsive to the electrical signals for programmably controlling the margin of sensitivity of the apparatus.
Claim 10
Dependent Claim
49 words
An implantable stimulator for detecting and treating cardiac events, comprising: sensing means for producing electrical signals representative of electrical activity of the heart indicative of rhythmic and arrhythmic contractions thereof, and signal processing means responsive to the electrical signals for programmably controlling the margin of sensitivity of the apparatus.
Claim 11
Dependent Claim
35 words
The implantable stimulator of Claim 7, wherein said signal processing means further comprises: a feedback loop for said amplifier means; and a microprocessor in said feedback loop for varying said amplification according to preselected algorithms.
Claim 12
Dependent Claim
20 words
The implantable apparatus of Claim 7, wherein detection of two low signals in a row causes an increase in gain.
Claim 13
Dependent Claim
17 words
The implantable apparatus of Claim 7, wherein detection of one high signal causes a decrease in gain.
Claim 14
Dependent Claim
80 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 signals paths for said detected signals, one of said paths having a feedback loop with means for automatically adjusting the gain of the amplifier means whereby the gain and threshold relationships between said dual signal paths maybe altered to produce variable sensing margins.
Claim 15
Dependent Claim
80 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 signals paths for said detected signals, one of said paths having a feedback loop with means for automatically adjusting the gain of the amplifier means whereby the gain and threshold relationships between said dual signal paths maybe altered to produce variable sensing margins.
Claim 16
Dependent Claim
24 words
An implantable cardiac stimulator according to Claim 11, wherein the algorithm controlling gain requires sensing of two lows in a row to increase gain.
Claim 17
Dependent Claim
20 words
An implantable cardiac stimulator according to Claim 11, wherein the algorithm controlling gain requires sensing one high to decrease gain.
Claim 18
Dependent Claim
26 words
An implantable cardiac stimulator according to Claim 11, wherein the algorithm controlling gain requires a ratio of greater than 1 to 1 to avoid T-wave sensing.
Claim 19
Dependent Claim
13 words
An implantable cardiac stimulator according to Claim 14, wherein said ratio is 2:1.
Claim 20
Dependent Claim
32 words
An implantable cardiac stimulator according to Claim 11, 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.
References Cited (Backward Citations)
EP0253505A2
Cited
DE3739014A1
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.