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US4574437A
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Methods and device for terminating tachycardia
Assignee: Pacesetter AB
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Filing: 1985-05-23
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Granted: 1986-03-11
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Expires: 2005-05-23
Abstract
Abstract A device for terminating tachycardia emits stimulation pulses to the heart synchronized with the heartbeats and a variable time delay. In order to quickly determine the proper delay time and thus increase the chances for successfully terminating tachycardia, the device has a unit for measuring the time between successive heartbeats and for deriving a plurality of different delay times therefrom of which the shortest delay time is a selected initial value and the difference between successive delay times becomes increasingly greater. The delay times are stored in a register which may be scanned in a specific sequence.
Inventors
- 👤 Christer H. A. Segerstad
- 👤 Hans Vallin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:31
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/24; A61B5/316; A61B5/318; A61B5/346; A61B5/349; A61B5/363; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/3621
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
150 words
A device for terminating tachycardia in a heart comprising: a detector means for detecting tachycardia and for generating an output signal upon the detection thereof; a measuring means for measuring the interval between successive tachycardia heartbeats; a delay generating means connected to said detector means and said measuring means, said delay generating means having an arithmetic means for deriving a plurality of different delay times from said interval, a shortest of said delay times being at least equal to the refractory period of said heart and successively derived delay times being increasingly longer by increasingly longer amounts, and having a counter means for determining said refractory period and a scanner means for scanning said delay times beginning with said shortest period; and an output means connected to said counter means for generating at least one stimulation pulse for supply to said heart at the end of each scanned delay time.
Claim 2
Independent Claim
150 words
A device for terminating tachycardia in a heart comprising: a detector means for detecting tachycardia and for generating an output signal upon the detection thereof; a measuring means for measuring the interval between successive tachycardia heartbeats; a delay generating means connected to said detector means and said measuring means, said delay generating means having an arithmetic means for deriving a plurality of different delay times from said interval, a shortest of said delay times being at least equal to the refractory period of said heart and successively derived delay times being increasingly longer by increasingly longer amounts, and having a counter means for determining said refractory period and a scanner means for scanning said delay times beginning with said shortest period; and an output means connected to said counter means for generating at least one stimulation pulse for supply to said heart at the end of each scanned delay time.
Claim 3
Dependent Claim
38 words
The device of claim 1 wherein said arithmetic means derives said plurality of different delay times by successively halving the difference between said interval and each preceding delay time and adding said difference to said shortest delay time.
Claim 4
Dependent Claim
33 words
The device of claim 1 further comprising a memory for storing said plurality of different delay times at respective addresses in a sequence for scanning of said address sequence by said scanner means.
Claim 5
Dependent Claim
12 words
The device of claim 3 wherein said counter-means centrifugally scans said memory.
Claim 6
Dependent Claim
79 words
The device of claim 3 wherein said detector means includes means for generating a signal after passage of a selected period during which no tachycardia is detected by said detector means thereby indicating successful termination of tachycardia by a last-scanned delay and said memory having means for shifting said address sequence upon receipt of said signal for bringing said last-scanned delay to an address which will be first scanned by said scanner means upon a renewed occurrence of tachycardia.
Claim 7
Dependent Claim
38 words
The device of claim 1 wherein said output circuit generates a plurality of said stimulation pulses at the end of each scanned delay time, the pulses in said plurality of stimulation pulses being at uniformly spaced temporal distances.
Claim 8
Dependent Claim
70 words
The device of claim 6 wherein, if said scanner means completes a delay time scanning cycle and tachycardia is not terminated, said scanner means continues a further scanning cycle of said delay times and further comprising means for supplying a signal from said counter means to said output circuit if tachycardia is not terminated for varying the number of stimulation pulses generated at the end of each scanned delay time.
Claim 9
Dependent Claim
69 words
The device of claim 6 wherein, if said scanner means completes a delay time scanning cycle and tachycardia is not terminated, said scanner means continues a further scanning cycle of said delay times and further comprising means for supplying a signal from said counter means to said output circuit if tachycardia is not terminated for varying said uniform temporal distances between said pulses in said plurality of stimulation pulses.
Claim 10
Dependent Claim
49 words
The device of claim 1 further comprising a time means for generating specified time intervals and a gate means disposed between said means and said heart and connected to said timer means for permitting heartbeat information to be supplied to said detector means only during said specified time intervals.
Claim 11
Independent Claim
112 words
A method for terminating tachycardia in a patient comprising the steps of: monitoring the heartbeats of the patient to detect tachycardia; selecting a shortest delay time which is at least equal to the refractory period of the patient's heart; deriving a plurality of increasingly longer delay times from said shortest delay time which differ in succession by increasingly longer amounts; storing said delay times in a selected sequence in sequential addresses of a memory; and if tachycardia is detected, scanning said sequential addresses and supplying a stimulation pulse to the heart following periodic heartbeats, said stimulation pulse being delayed by differently increasingly longer delay times from said sequence until tachycardia is terminated.
Claim 12
Independent Claim
112 words
A method for terminating tachycardia in a patient comprising the steps of: monitoring the heartbeats of the patient to detect tachycardia; selecting a shortest delay time which is at least equal to the refractory period of the patient's heart; deriving a plurality of increasingly longer delay times from said shortest delay time which differ in succession by increasingly longer amounts; storing said delay times in a selected sequence in sequential addresses of a memory; and if tachycardia is detected, scanning said sequential addresses and supplying a stimulation pulse to the heart following periodic heartbeats, said stimulation pulse being delayed by differently increasingly longer delay times from said sequence until tachycardia is terminated.
Claim 13
Dependent Claim
51 words
A method for terminating tachycardia as claimed in claim 10 comprising the additional step of: shifting said sequential addresses in said memory after tachycardia is terminated such that the delay time which successfully terminated tachycardia is stored in an address which will be first scanned upon a renewed occurrence of tachycardia.
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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) | 1989-03-10 | 1989-09-09 | 1990-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-10 | 1993-09-09 | 1994-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-10 | 1997-09-09 | 1998-03-11 | $7700.00 | Window Closed / Lapsed |