TACHYCARDIA DETECTOR

• US 3,823,708 A
• Filed: 06/08/1972
• Issued: 07/16/1974
• Est. Priority Date: 06/08/1972
• Status: Expired due to Term

• Current Assignee: Richard D. Lawhorn
• Original Assignee: Richard D. Lawhorn
• Inventors: Lawhorn, Richard D.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/260,775
• Time in Patent Office: 768 Days
• Field of Search: 128/2.5P,2.5R,2.5T,2.6A,2.6B,2.6E,2.6F,2.6R
• US Class Current: 600/514
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/02455 provided with high/low alarm devices
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: Y10S 128/904 Telephone telemetry

Abstract

A selective circuit is provided for passing only selected waveforms of a desired polarity from a complex input waveform. The circuit is particularly adapted for use in a heart ventricular arrhythmia detector. In such a detector, it is first necessary to differentiate the abnormal negative ventricular ectopic beats from the normal negative Q & S waves. After these abnormal beats are detected, they are accumulated and, if a number of them occur within a limited period of time, an alarm circuit is actuated. One embodiment also includes means for detecting bradycardia and tachycardia. A further embodiment provides means for transmitting an ECG over the telephone.

Claims

1. A heart tachycardia detector for detecting a plurality of closely occuring negative ventricular ectopic beats wherein said negative beats are discriminated from the normal PQRST electrocardiograph complex and said ventricular ectopic negative beats exceed the negativity of normal Q and S waves, comprising in combination:

a. a pair of electrodes applied to a body, b. a first amplifier means connected to said electrodes, said amplifier amplifying all voltages imposed on said electrodes, c. a second amplifier means, said second amplifier means amplifying only negative voltages applied to said electrodes, d. first storage means to establish a normal threshold of negative voltage, e. third amplifier means for amplifying only voltages exceeding said threshold, f. second storage means for storing the thus amplified voltage, said second storage means having a trigger level and a discharge means, and g. output signal means connected to said second storage means whereby an output signal is produced only when said trigger level is reached.

2. The structure of claim 1 wherein an alarm device is provided whereby said alarm is actuated upon receipT of said signal.

3. The structure of claim 2 wherein the alarm is an audible alarm.

4. The structure of claim 2 wherein said detector includes a touch plate whereby a wearer can touch said plate and actuate said alarm, and circuit including means whereby said alarm is modulated by signals received by the electrodes.

5. The structure of claim 1 wherein a capacitor is employed as the second storage means, said capacitor having a plurality of selectable discharge paths.

6. The circuit of claim 5 wherein a first capacitor is normally fully charged and each signal impulse transfers a portion of said charge to a second capacitor, said second capacitor having a selectable discharge path and means whereby the alarm is sounded when said second capacitor is charged to a pre-established level by a succession of signals.

7. The structure of claim 1 wherein said detector includes fourth amplifier means connected to the output from said first amplifier means and wherein said fourth amplifier means includes means for detecting the frequency of positive R signals and has means for determining whether the frequency of said R signals deviate in frequency from an established value and means for producing an output signal when a deviation from said value is detected.

8. The structure of claim 7 wherein each R signal actuates a multivibrator to produce an output pulse of constant width and height and wherein said pulses are accumulated in a capacitor, said capacitor having a constant discharge path, and means whereby said output signal is actuated if the capacitor becomes discharged below a certain level or charged above a certain level.

9. The structure of claim 1 wherein said electrodes are additionally attached to an on-off circuit whereby applying the electrodes to the body of a user actuates the circuit.

10. The structure of claim 1 wherein said first amplifier has an output during the duration of a positive R wave and wherein said output of said first amplifier has means connected thereto for generating a blanking pulse during the negative slope of the RS wave, said pulse being fed to the input of said third amplifier and cutting off said third amplifier during only the period of said output.