Implantable cardiac pacer with characteristic controllable circuit and control device therefor
First Claim
1. An implantable cardiac pacer comprising:
- a. pulse generator means for applying stimulus pulses to a heart, said generator means having at least one operating characteristic that is subject to variation,b. means for detecting control signals generated remotely from said pacer,c. ring counter means having a plurality of output terminals, said ring counter means being responsive to each in a succession of detected control signals by respectively changing the voltage states on said output terminals from a first state to different states to thereby produce a sequence of binary number representative signals on said output terminals,d. means connected with said output terminals and responsive to each binary number change thereon by varying said characteristic,e. means for resetting said ring counter means for its output terminals to attain said first state in response to a predetermined number of binary number states having occurred,f. said ring counter means comprising a series of interconnected flip-flops, said flip-flops respectively having output terminals (Q) and clock input signal terminals (C) and data input terminals, said flip-flops each being characterized by transferring whichever high or low state signal is on its data input terminal to its Q output terminal when a clock signal is applied to its C input terminal,g. said Q output terminal of the first and next flip-flops other than the last flip-flop in the series being connected to the ensuing data input terminal of subsequent flip-flops,h. said C input terminal being connected for simultaneously receiving a clock signal corresponding with each detected signal for sequentially advancing a signal that is initially on the data input terminal of the first flip-flop to the Q output terminal of the last flip-flop.i. gate means having a plurality of input terminals connected to receive signals opposite of the signals on the Q output terminals, respectively, of each but the last flip-flop in said series, said gate means having an output terminal coupled with the data input terminal of said first flip-flop, the output terminal of said gate means changing state when the flip-flops other than the last flip-flop are operated to have their output terminals all at the same state to thereby apply an initializing signal state to the data input terminal of said first flip-flop and to establish the Q input terminal of the last flip-flop in a final state corresponding with said initial state, whereby the next detected control signal will start recycling of said flip-flops, andj. the aforesaid ring counter output terminals being the points intermediate the Q output terminals and data input terminals of successive flip-flops.
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Abstract
An implantable cardiac pacer has a counter for encoding different binary numbers in response to clock pulses applied thereto through an internal clock pulse generating switch that can be activated from outside of the subject'"'"'s body by application of radiant energy. The binary numbers are decoded with switches that sequentially connect and disconnect circuit elements to control a characteristic of the pacer such as its stimulus pulse width, pulse amplitude, pulse rate and others. The clock pulse switch may be one that is activated with light or pressure but is preferably a magnetic switch system controlled by a shaped magnetic field for preventing inadvertent operation. The encoder counter recycles or resets to its initial value when a predetermined number of clock pulses are applied.
42 Citations
11 Claims
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1. An implantable cardiac pacer comprising:
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a. pulse generator means for applying stimulus pulses to a heart, said generator means having at least one operating characteristic that is subject to variation, b. means for detecting control signals generated remotely from said pacer, c. ring counter means having a plurality of output terminals, said ring counter means being responsive to each in a succession of detected control signals by respectively changing the voltage states on said output terminals from a first state to different states to thereby produce a sequence of binary number representative signals on said output terminals, d. means connected with said output terminals and responsive to each binary number change thereon by varying said characteristic, e. means for resetting said ring counter means for its output terminals to attain said first state in response to a predetermined number of binary number states having occurred, f. said ring counter means comprising a series of interconnected flip-flops, said flip-flops respectively having output terminals (Q) and clock input signal terminals (C) and data input terminals, said flip-flops each being characterized by transferring whichever high or low state signal is on its data input terminal to its Q output terminal when a clock signal is applied to its C input terminal, g. said Q output terminal of the first and next flip-flops other than the last flip-flop in the series being connected to the ensuing data input terminal of subsequent flip-flops, h. said C input terminal being connected for simultaneously receiving a clock signal corresponding with each detected signal for sequentially advancing a signal that is initially on the data input terminal of the first flip-flop to the Q output terminal of the last flip-flop. i. gate means having a plurality of input terminals connected to receive signals opposite of the signals on the Q output terminals, respectively, of each but the last flip-flop in said series, said gate means having an output terminal coupled with the data input terminal of said first flip-flop, the output terminal of said gate means changing state when the flip-flops other than the last flip-flop are operated to have their output terminals all at the same state to thereby apply an initializing signal state to the data input terminal of said first flip-flop and to establish the Q input terminal of the last flip-flop in a final state corresponding with said initial state, whereby the next detected control signal will start recycling of said flip-flops, and j. the aforesaid ring counter output terminals being the points intermediate the Q output terminals and data input terminals of successive flip-flops.
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2. A device for implantation in a body to affect a physiological function, comprising:
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a. means for producing electrical signals for affecting said function, b. control means for altering at least one operating characteristic of said signal producing means, c. at least one and another magnetically operable switch means interconnected with said control means, each of said switch means being operable between conductive and nonconductive states under the influence of a magnetic field, said control means responding to said switch means being in predetermined states by altering said characteristic, d. said switch means being arranged for a magnetic field of predetermined configuration to change at least one of said switch means to its said predetermined state while said at least another switch remains in a said predetermined state, e. said at least one switch means being normally open and nonconductive and said at least another switch means being normally closed and conductive, said switch means being in their predetermined states when they are closed, said switch means being arranged near each other for a stray magnetic field which is capable of closing and normally open switch means to also open said normally closed switch means. - View Dependent Claims (3, 4)
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5. An implantable cardiac pacer comprising:
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a. pulse generator means for applying stimulus pulses to the heart, said pulse generator means having at least one operating characteristic that is subject to alteration, b. means for altering said characteristic in response to control signals, c. circuit means including magnetically operable switch means for supplying control signals to said means for altering said characteristic, at least one of said switch means being normally open and closeable under the influence of a magnetic field to supply a control signal and at least another of said switch means being normally closed and operable under the influence of a magnetic field, d. said switch means being arranged for a magnetic field which couples simultaneously with both of said switch means to open said normally closed switch means and close said normally open switch means to thereby prevent supplying a control signal and for a magnetic field which couples with at least said one switch means without effectively coupling with said other switch means to close said one switch means and thereby permit supplying a control signal to said means for altering a characteristic.
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6. An implantable cardiac pacer comprising:
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a. pulse generator means for applying stimulus pulses to a heart, said pulse generator means having at least one operating characteristic that is subject to variation, b. means responsive to control signals by varying said characteristic, c. plural switch means operable between conductive and nonconductive states for controlling said control signal responsive means, at least one of said switch means being normally in one state and spaced from the other by a predetermined distance, said one switch means and the other being required to change their states in coincidence for controlling said control signal responsive means. - View Dependent Claims (7)
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8. An implantable cardiac pacer comprising:
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a. pulse generator means for applying stimulus pulses to a heart, said pulse generator means having at least one operating characteristic that is subject to variation, b. means responsive to control signals by varying said characteristic, c. switch means in a circuit for supplying control signals to said control signal responsive means, d. said switch means comprising magnetically operable switches including a first normally open switch, a normally closed switch and a second normally open switch, e. said switch means being arranged for a magnetic field which couples with one or both of said normally open switches and simultaneously with said normally closed switches to at least open said normally closed switch to prevent establishing said circuit for supplying a control signal and arranged for a magnetic field to couple with both of said normally open switches to enable supplying a control signal.
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9. A portable hand held device for controlling the states of magnetically operable switch means in an implantable cardiac pacer to change an operating characteristic thereof wherein certain of said switch means are spaced apart from each other and normally in one state and another of said switch means is normally in another state and all of said switch means are required to be in the same state simultaneously to cause a change in said characteristic, said device comprising:
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a. magnet means for producing substantially isolated magnetic fields corresponding in number with said switch means which are normally in said one state and with said magnet means spaced apart a predetermined distance from each other for magnetically coupling respectively with said spaced apart switch means to change their states while remaining substantially magnetically uncoupled from said other switch means to permit its state to remain unchanged, b. said magnet means being arranged with similar polarity poles of each of them adjacent each other and opposite polarity poles of each of them remote from said similar polarity poles and from each other, to provide a field free region between said adjacent poles, and c. resin encapsulating said magnet means and maintaining said magnet means at said predetermined distance, said resin and magnet means comprising a unitary device that must be placed in a substantially singular position proximate to said pacer to cause said switch means to be in said same state simultaneously.
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10. A device for controlling the states of magnetically operable switch means in an implantable cardiac pacer to change an operating characteristic thereof wherein certain of said switch means are spaced apart from each other and normally in one state and another of said switch means is normally in another state and all of said switch means are required to be in the same state simultaneously to cause a change in said characteristic, said device comprising:
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a. means for producing substantially isolated magnetic fields corresponding in number with said switch means which are normally in said one state and spaced apart from each other by a sufficient amount for coupling respectively with said spaced apart switch means to change their states while remaining substantially magnetically uncoupled from said other switch means to permit its state to remain unchanged, b. said magnetic field producing means being arranged with similar polarity poles of each of them adjacent each other and opposite polarity poles of each of them remote from said similar polarity poles and from each other, to provide a field free region between said adjacent poles, c. means for supporting said magnetic field producing means, and d. said magnetic field producing means comprising first and second permanent magnets and magnetically permeable members magnetically coupled with said similar polarity poles, respectively, and each terminating in a region intermediate said similar and opposite poles, respectively, to effect a field free region between them.
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11. A hand held device for operating magnetically operable switch means in an implantable cardiac pacer to change an operating characteristic thereof which switch means comprise a normally open first magnetically operable switch, a second normally closed magnetically operable switch and a third normally open magnetically operable switch, said switches being serially connected in the stated order, said device comprising:
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a. at least a pair of magnet means arranged with poles of the same polarity adjacent each other and poles of opposite polarity spaced remotely from each other and remotely from said poles of same polarity to produce individual magnetic fields extending from the corresponding adjacent poles of each magnet to their respective other polarity poles with no substantial magnetic field between said magnets, said fields being spaced apart sufficiently to couple simultaneously only with said first and third normally open switches in said pacer to close the same without operating said normally closed switch in said pacer, and b. resin encapsulating said magnet means, said resin and magnet means comprising a unitary device that must be placed in a substantially singular position proximate to said pacer to close said normally open switches without opening said normally closed switch.
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Specification