US 3,945,387 AGranted

Implantable cardiac pacer with characteristic controllable circuit and control device therefor

AssigneeGeneral Electric Company

InventorTheodore P. Adams

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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.

Claims11

Dependent claims

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, and
j. the aforesaid ring counter output terminals being the points intermediate the Q output terminals and data input terminals of successive flip-flops.

7 more elements

A device for implantation in a body to affect a physiological function, comprising:

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.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/504,346Filed 9 Sep 1974
Granted: 23 Mar 1976
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

A61N 1/37229
Circuits for electromagnetic coupling: shape or location of the implanted or external antenna
A61N 1/025
Details: digital circuitry features of electrotherapy devices, e.g. memory, clocks, processors
A61N 1/37211
Arrangements in connection with the implantation of stimulators: means for communicating with stimulators
A61N 1/37217
Means for communicating with stimulators: characterised by the communication link, e.g. acoustic or tactile