Digital electrocardiograph interpreter

Claim 1

In combination with an electrocardiograph assembly that includes a solenoid-operated recorder pen drive coil that receives EKG electrical signals from a patient and visually records a graph thereof on an elongate strip of moving paper, a device for selectively displaying a digital form, the time interval required to form a selected wave or group of waves in said signal along the X axis thereof, said signal including P, R, T and U positive waves and Q and S negative waves, said device including: a. an electrical conductor that receives the EKG electric signal from said solenoid that drives said recorder pen; b. first means that includes an isolation amplifier and filter for receiving said EKG signal from said electrical conductor and which filters electric signals therefrom that originate from a source of domestic electric power; c. second means for dividing the filtered EKG signal from said first means into first and second signal portions; d. third means that include an integrator amplifier, absolute value amplifier and overdriven amplifier for receiving said first signal portion and thereafter sequentially removing noise from said first signal portion, inverting the Q and S waves of said first signal portion, and squaring said P, Q, R, S, T and U waves to provide an overdriven signal; e. an and-gate having first and second inputs and an output; f. fourth means for continuously delivering spaced electric pulses of a first polarity to said first input; g. fifth means that include a differential amplifier, a multiple bit counter, a logic unit and manually operated signal controlled by said overdriven signal for selectively delivering an electric signal of said first polarity to said second input during the time interval a predetermined and selected portion of said EKG signal is being formed; h. a multiple decade counter that receives said spaced electric pulses from said output of said and-gate; i. a hold register that receives the output from said multiple decade counter; j. a multiplexer in electrical communication with said hold register; k. first second and third display tubes that indicate by digits thereon, thousandths, hundredths and tenths of a second; l. sixth means in electrical communication with said multiplexer and first, second and third display tubes, said sixth means being actuated by the output from said multiplexer to actuate said display tubes to visually indicate the tiMe duration required to form said selected portion of said EKG signal; m. seventh means for eliminating all but said R wave from said second signal portion; n. eighth means for storing said R wave of said second signal as an electric pulse until just prior to the forming of the P wave of the following EKG signal; o. ninth means for using a portion of said stored electric pulse to cause the information in said counter to be transferred to said register just prior to said P wave of the following EKG signal; and p. tenth means for using a portion of said stored electric pulse to clear said hold register prior to said information in said counter being transferred thereto.