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US3911929A
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Demand cardiac pacer
Assignee: Medtronic Inc
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Filing: 1974-05-20
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Granted: 1975-10-14
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Expires: 1994-05-20
Abstract
Abstract In a demand cardiac pacer including a resettable pulse generator and a sense amplifier adapted to be connected to the heart for generating a reset signal in response to a sensed heartbeat, the improved apparatus including a frequency detector for passing those reset signals whose interval is greater than a predetermined value and blocking those reset signals whose interval is less than the predetermined value. The frequency detector includes a timing circuit for establishing a predetermined period of time following each reset signal and circuitry for blocking all reset signals subsequent to a time period establishing signal. In a preferred embodiment, the blocking circuitry consists of a transistor switch for shunting the reset signals during the predetermined period of time and a delay element for allowing the passage of an initial time period establishing signal.
Inventors
- 👤 David H Gobeli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:10
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/365
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
130 words
In a demand cardiac pacer of the type having a resettable pulse generator and having sense amplifier means adapted to be connected to the heart and responsive to heart activity for generating pulse generator reset signals, the improvement which comprises: means for establishing a first predetermined period of time; means responsive to said sense amplifier means and connected to said first time period establishing means for initiating the operation of said first time period establishing means On the occurrence of each reset signal; means operative during said first predetermined period of time for blocking said reset signals from said pulse generator; and means for delaying the operation of said blocking means for a second, shorter predetermined period of time following initiating the operation of said first time period establishing means.
Claim 2
Dependent Claim
130 words
In a demand cardiac pacer of the type having a resettable pulse generator and having sense amplifier means adapted to be connected to the heart and responsive to heart activity for generating pulse generator reset signals, the improvement which comprises: means for establishing a first predetermined period of time; means responsive to said sense amplifier means and connected to said first time period establishing means for initiating the operation of said first time period establishing means On the occurrence of each reset signal; means operative during said first predetermined period of time for blocking said reset signals from said pulse generator; and means for delaying the operation of said blocking means for a second, shorter predetermined period of time following initiating the operation of said first time period establishing means.
Claim 3
Dependent Claim
17 words
The cardiac pacer of claim 1 wherein said blocking means comprises means for shunting said reset signals.
Claim 4
Dependent Claim
14 words
The cardiac pacer of claim 2 wherein said shunting means comprises transistor switch means.
Claim 5
Dependent Claim
17 words
The cardiac pacer of claim 3 wherein said first time period establishing means comprises resettable timing means.
Claim 6
Dependent Claim
14 words
The cardiac pacer of claim 4 wherein said delaying means comprises capacitive timing means.
Claim 7
Dependent Claim
52 words
The cardiac pacer of claim 1 wherein said first time period establishing means comprises first capacitive timing means and means for charging said first capacitive timing means in the interval between said reset signals, said initiating means comprising means for discharging said first capacitive timing means in response to said reset signals.
Claim 8
Dependent Claim
33 words
The cardiac pacer of claim 6 wherein said blocking means further comprises first switch means for switching from one state to another in response to the discharge of said first capacitive timing means.
Claim 9
Dependent Claim
50 words
The cardiac pacer of claim 7 wherein said blocking means further comprises normally-off switch means connecting said sense amplifier to ground and responsive to said first switch means for switching on and shunting said reset signals in response to the switching of said first switch means to said other state.
Claim 10
Dependent Claim
42 words
The cardiac pacer of claim 8 wherein said delaying means comprises second capacitive means interconnecting said first and normally-off switch means for delaying the response of said normally-off switch means to the switching of said first switch means to said other state.
Claim 11
Dependent Claim
17 words
The cardiac pacer of claim 9 wherein said first and normally-off switch means comprise transistor switch means.
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) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |