Electrocardiac information monitoring apparatus

• US 3,913,567 A
• Filed: 11/01/1973
• Issued: 10/21/1975
• Est. Priority Date: 05/10/1971
• Status: Expired due to Term

• Current Assignee: LS Medical Instruments Incorporated
• Original Assignee: George L. Streckmann
• Inventors: Streckmann, George L.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/411,768
• Time in Patent Office: 719 Days
• Field of Search: 128/2.6B,2.6G,2.6R,2.5Q,2.5R,2.1A,2.1R 360/29,32,40 329/106 332/9R,15
• US Class Current: 600/524
• CPC Class Codes: A61B 5/336 Magnetic recording apparatus

Abstract

Disclosed is electrocardiographic monitoring apparatus including a magnetic tape recorder having a dual channel input for receiving and recording EKG signal information from a human being simultaneous with voice communication from that human being. The audio and EKG signals are recorded on two tracks of magnetic tape for subsequent recreation by a dual channel magnetic tape reproducer. Novel encoding and decoding circuitry are also disclosed, the circuitry employing operational amplifiers interconnected with capacitors and diodes.

Claims

1. Apparatus for monitoring cardiac information about a human being, comprising:

a. record means having two channels, b. one of said two channels including transducer means for converting voice communication from said human being into representative audio signals, c. means coupled to said transducer means for recording said audio signals onto one track of a magnetic tape, d. the other of said two channels including electrode means adapted to be affixed to said human being for producing electrocardiac signals, e. encoding means for modulating said electrocardiac signals to produce output signals from said encoding means comprising a series of constant magnitude positive and negative pulses, the ratio of the width of the negative pulses to the width of the positive pulses being proportional to the amplitude of the said electrocardiac signals, said encoding means comprising an input teRminal coupled to said electrode means, an output terminal, a capacitor, an operational amplifier having its input connected to said input terminal and its output connected to said output terminal with the negative input terminal of the operational amplifier coupled to ground through said capacitor, and a pair of feedback resistors respectively coupled from the output of the operational amplifier to the negative and positive inputs of said operational amplifier, f. means for recording said modulated output signals onto another track of said magnetic tape, g. reproduce means having two channels, h. a first playback head within one of said reproduce channels for reproducing said audio signals on said one track of said magnetic tape, i. loudspeaker means coupled to said playback head for recreating said voice communication, j. a second playback head for reproducing signals from said second track of said magnetic tape, k. decode means coupled to said second playback head for effectively restoring the said reproduced signals from the second track to the same waveshape as the said modulated output signals from the encoding means, l. filter means for converting said restored signals to electrocardiac signals of the type produced by said electrode means, and m. means coupled to said filter means for displaying said electrocardiac signals.

2. The apparatus as described in claim 1 wherein said decode means comprises an input and output terminal, a second capacitor, an operational amplifier having its input coupled to the input terminal of said decode means and its output coupled to said output terminal, with the negative input terminal of the operational amplifier of the decode means coupled through said second capacitor to ground, a feedback resistor coupling the output terminal of the second-mentioned operational amplifier to the positive input terminal thereof, and a paralleled set of diodes coupled to said input terminal and to the negative input terminal of said second-mentioned operational amplifier.