PORTABLE ELECTROCARDIOSCOPE

• US 3,858,576 A
• Filed: 05/23/1973
• Issued: 01/07/1975
• Est. Priority Date: 05/23/1973
• Status: Expired due to Term

• Current Assignee: Heinz Dehnert, Hermann Steiert
• Original Assignee: Heinz Dehnert, Hermann Steiert
• Inventors: Dehnert, Heinz, Steiert, Hermann
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/362,973
• Time in Patent Office: 594 Days
• Field of Search: 128/2.6B,2.6G,2.6R 315/29 328/171
• US Class Current: 600/525
• CPC Class Codes: A61B 5/332 Portable devices specially adapted therefor
• CPC Class Codes: A61B 5/336 Magnetic recording apparatus
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor

Abstract

A portable electrocardioscope is provided taking the form of a housing having a plurality of terminals at one end for direct engagement with the chest of a patient, a cathode ray tube display at its other end, and a battery-operated circuit within the housing for converting signals appearing on the terminals into a visual display on the cathode ray tube.

Claims

1. An electrocardioscope comprising a plurality of input terminals adapted to receive cardiac signals representing the cardiac action of a patient, display means, and a control circuit disposed between said terminals and said display means for processing said cardiac signals to produce output signals which are coupled to said display means to produce a visual representation of said cardiac action, said control circuit comprising means connected across a pair of said terminals and responsive to said received cardiac signals for producing an input signal, a first pair of diodes connected in series with one another across said pair of terminals, a second pair of diodes connected in series with one another and in parallel with said first pair of diodes, said first pair of diodes being poled oppositely to said second pair of diodes, means coupling said input signal across said parallel-connected pairs of diodes, a differential amplifier comprising first and second interconnected transistors, capacitor means coupling the opposing ends of said parallel-connected diode pairs to said first and second transistors respectively, means connecting the mid-junction of said first pair of diodes to the mid-junction of said second pair of diodes, further capacitor means coupling the interconnected mid-junctions of said pairs of diodes to said first and second transistors respectively, means defining a point of reference potential, a pair of oppositely poled zener diodes connected in series with one another between the interconnected mid-junctions of said diode pairs and said point of reference potential, and output means coupling the output of said differential amplifier to said display means.

2. The combination of claim 1 including a dc battery connected to said differential amplifier to energize said amplifier.

3. The combination of claim 1 wherein said control circuit is mounted on a chassis, said point of reference potential compriSing said chassis, said input terminals including a terminal connected to said chassis.

4. The combination of claim 1 wherein said display means comprises a cathode ray tube having means for deflecting the beam of said tube in X and Y directions, said output means including a Y-amplifier coupled to the output of said differential amplifier, the output of said Y-amplifier being connected to said Y-deflecting means for controlling the Y-deflection of said cathode ray tube, and means for generating a sweep signal for controlling the X-deflecting means of said cathode ray tube.

5. The combination of claim 4 including means for recording signals, and terminal means connected to the input of said Y-amplifier for coupling signals to and from said recording means.

6. The combination of claim 4 wherein said means for generating said sweep signal includes a storage capacitor, a dc current source for charging said storage capacitor, a discharge circuit connected across said capacitor for selectively discharging said storage capacitor, said discharge circuit including means connecting said capacitor to a normally nonconductive programmable unijunction transistor for rendering said transistor conductive when the charge potential across said storage capacitor reaches a predetermined level, third and fourth transistors connected in series with one another to render the conductivity of said third transistor dependent upon the conductivity of said fourth transistor, means coupling the output of said Y-deflection amplifier to said third transistor, means responsive to the X-deflection of the cathode ray tube beam for controlling the conductivity of said fourth transistor, and means coupling a signal from said third transistor to said programmable unijunction transistor for rendering said programmable unijunction transistor conductive to discharge said storage capacitor in response to conduction of said third transistor due to the occurrence of a signal in excess of a predetermined minimum amplitude at the output of said Y-deflection amplifier concurrent with conduction of said fourth transistor due to deflection of the beam in an X-direction beyond a predetermined position on the screen of said cathode ray tube.

7. The combination of claim 4 wherein said electrocardioscope includes an elongated, portable housing containing said control circuit and also containing a battery supply for said control circuit, said housing having said terminals mounted on one end thereof for direct engagement with the chest of a patient to provide said cardiac signals, said cathode ray tube being mounted in said housing with its screen exposed to view through the other end of said housing.

8. The combination of claim 7 including pressure sensitive switch means mounted on said housing for automatically controlling the energization of said circuit from said battery supply.

9. The combination of claim 8 wherein said switch means is mounted adjacent said terminals, said switch means being operative to effect energization of said circuit only when said switch means and electrodes are in engagement with the chest of a patient.

10. The combination of claim 7 including recording means, a microphone, and a terminal on said housing connected to said microphone for coupling audio signals to and from said recording means.

11. The combination of claim 1 wherein said means for producing said input signal comprises a frequency filter connected between said pair of terminals and said parallel-connected pairs of diodes.