US3109430A - Cardiac nerve control device - Google Patents

Description

Nov. 5, 1963 M. TISCHLER 3,109,430

CARDIAC NERVE CONTROL DEVICE Filed Jan. 29, 1959 IN VENTOR 0 Morris r/sm/er BY Mm L?2%4/ ATTORNEY United States Patent O areasso CARDIAC NERVE CONTROL DEVICE Morris Tischlcr, Baltimore, Md, assignor to Electronic Aids, Inc, Baltimore, Md., a corporation oi Maryland Filed Jan. 29, 1959, Ser. No. 789,989 2 Claims. (til. 128 -422) This invention relates generally to surgical apparatus, and more particularly it pertains to electrical impulse generators for stimulating the cardiac nerves.

It is well known that the muscles of a body can be caused to react to an electrical stimulus. For this purpose, various electrical generators have been devised and used in the art.

An important special adaptation of this principle of electrical stimulus has been the application of regularly spaced electrical pulses to the cardiac nerves for reviving a faltering heart beat. Inasmuch as a great many cases of this sort are of an emergency nature, it is not always possible to have at hand the necessary apparatus IfOI treatment of a patient.

In order to be fully prepared for emergency cardiac nerve treatment of the patient of either the open or closed chest type, a physician needs a versatile, selfpowered, compact and light weight instrument which can be included in his emergency kit.

lit is an object of the present invention, there-fore, to provide a battery-supplied, transistor-operated pulse generating heart stimulator including repetition rate control and amplitude control of a generated unidirectional pulse and having provisions for either open or closed chest electrode use.

Other objects of this invention are to provide a novel transistorized heart stimulator which is compact, which is economical to manufacture, efiieient and reliable in operation, and which is easy to maintain.

These and other objects and advantages of this invention will become more readily apparent and understood irom the accompanying specification and single FIGURE which illustrates a schematic diagram of a transistorized heart stimulator.

A junction type tnansistor 19, as depicted schematically in the drawing, is arranged in a blocking oscillator circuit. This circuit includes acapacitor 12 and areactor 14 connected serially between thebase electrode 16 and emitter electrode 18 of the transistor 10.

Asupply capacitor 20, charged through aresistor 22 from abattery 24, is provided in the circuit to furnish operating current to thecollector electrode 26 and to the emitter electrode 18 through acharging choke coil 28. A variablebase biasing resistor 30 and a limitingresistor 32 are provided in the circuit as shown and are serially connected between thebase electrode 16 and thecollector electrode 26.

Acoupling capacitor 34 is also provided in the circuit to effectively connect aresistive potentiometer 36 across thecharging choke coil 28. A selected portion of the current developed acrosspotentiometer 36 is fed by means of avariable tap 38 to abase electrode 42 of asecond junction transistor 40 arranged in an emitter follower circuit.

Bias current is supplied through the potentiometer .36 to thebase electrode 42 from the positive side of thesupply capacitor 20. The negative side of the capacitor is connected to thecollector electrode 44 of thesecond junction transistor 40.

Theemitter electrode 46 of transistor is connected to alow tap 48 of an autotransformer 50' which has its common connection '52 connected to the positive side of thesupply capacitor 20.

3,199,430 Patented Nov. 5, 1963 ice Between anintermediate tap 54 and thecommon tap 52 of the autotransformer 56), there is provided arectifier diode 56. A twoposition switch 60 is provided in the circuit to select the voltage provided by theautotransformer 56 either from theintermediate tap 54 or ahigh voltage tap 58 therefor for a pair ofapplication electrodes 62.Electrodes 62 can be in the form of chest plates, if desired.

A switch 64- as well as acurrent monitoring jack 66 is provided in the circuit in series with thebattery 24. Alamp 68 is connected across thecharging choke 28, and it is used to give a visual indication of the generated pulse which may also be monitored at a test point 79.

In actual operation or the transistorized heart stimulator, the electrodes are positioned in the proper position on the chest of the patient. The repetition rate of the blocking oscillator transistor 10 is then adjusted as desired by thebase biasing resistor 30. The amplitude of the voltage discharge from theelectrodes 62 is adjusted by thepotentiometer tap 38. High voltage or low voltage for closed or open chest cardiac stimulation, respectively, is chosen by means of theswitch 60.Diode 56 suppresses oscillations and assures unipotential pulse output.

Obviously, many other modifications of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A cardiac nerve control device, comprising a battery, a transistorized blocking oscillator circuit to translate the power supplied by said battery into electrical impulses and having means to control the frequency of said impulses, means coupled to said blocking oscillator circuit to control the amplitude and shape of said inrpulses to form an electrical signal having the efi'ect of stimulating normal action of the heart when applied to the nerves and/or muscles thereof, a transistorized emitter-follower circuit coupled to said last mentioned means to receive and amplify said signal, means including a step-up autotransformer coupled to said emitter-follower circuit to receive said signal and vary its voltage to high and low levels for closed and open chest heart stimulation, respectively, and a pair of spaced electrodes to apply the output of said step-up autotransformer to the nerves and/or muscles of the heart.

2. The cardiac nerve control device of claim 1 and in addition a unilaterally conducting element coupled 0 to said step-up autotransformer for suppressing spurious oscillations and assuring a unipotential pulse output of said step-up autotransformer.

References Cited in the file of this patent tronic Engineering, pp. 188 190.

Denny: Chronaxie Meter, June 1944 Electronic Engineering, pp. 26-28.

Molyneux article, Electronic Engineering, March 1957, pages -127.

Her-rod et al. article, Surgery, September 1952, pages 510-511. (Copy in Division 55.)

Claims (1)

1. A CARDIAC NERVE CONTROL DEVICE, COMPRISING A BATTERY, A TRANSISTORIZED BLOCKING OSCILLATOR CIRCUIT TO TRANSLATE THE POWER SUPPLIED BY SAID BATTERY INTO ELECTRICAL IMPULSES AND HAVING MEANS TO CONTROL THE FREQUENCY OF SAID IMPULSES, MEANS COUPLED TO SAID BLOCKING OSCILLATOR CIRCUIT TO CONTROL THE AMPLITUDE AND SHAPE OF SAID IMPULSES TO FORM AN ELECTRICAL SIGNAL HAVING THE EFFECT OF STIMULATING NORMAL ACTION OF THE HEART WHEN APPLIED TO THE NERVES AND/OR MUSCLES THEREOF, A TRANSISTORIZED EMMITER-FOLLOWER CIRCUIT COUPLED TO SAID LAST MENTIONED MEANS TO RECEIVE AND AMPLIFY SAID SIGNAL, MEANS INCLUDING A STEP-UP AUTOTRANSFORMER COUPLED TO SAID EMITTER-FOLLOWER CIRCUIT TO RECEIVE SAID SIGNAL AND VARY ITS VOLTAGE TO HIGH AND LOW LEVELS FOR CLOSED AND OPEN CHEST HEART STIMULATION, RESPECTIVELY, AND A PAIR OF SPACED ELECTRODES TO APPLY THE OUTPUT OF SAID STEP-UP AUTOTRANSFORMER TO THE NERVES AND/OR MUSCLES OF THE HEART.

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