CONTOUROGRAPH SYSTEM FOR MONITORING ELECTROCARDIOGRAMS

• US 3,638,066 A
• Filed: 08/21/1970
• Issued: 01/25/1972
• Est. Priority Date: 08/21/1970
• Status: Expired due to Term

• Current Assignee: Donald G. Mauldin, Donald P. Golden Jr, N/a,, Paine Thomas O Administrator of The National Aeronautics and Space, Roger A. Wolthuts
• Original Assignee: Donald G. Mauldin, Donald P. Golden Jr, N/a,, Paine Thomas O Administrator of The National Aeronautics and Space, Roger A. Wolthuts
• Inventors: Wolthuts, Roger A., Paine, Thomas O. Administrator of the National Aeronautics and Space, N/a,, Golden, Donald P. Jr., Mauldin, Donald G.
• Primary Examiner(s): Bennett, Jr., Rodney D.
• Assistant Examiner(s): Potenza, J. M.
• Application Number:
  US05/065,840
• Time in Patent Office: 522 Days
• Field of Search: 315/19,25 128/2.6R,2.6G,2.6A
• US Class Current: 315/383
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: G01R 13/206 Arrangements for obtaining a 3- dimensional representation stereoscopic T.V. H04N13/00

Abstract

The system of the present invention processes semiperiodic electrical signals such as an electrocardiogram to produce a real time signal display on the face of a variable persistence cathode ray tube in an oscilloscope. Each cycle of the signal being processed is formed on a separate horizontal base line which is spaced vertically below the trace formed by the preceding cycle. Each of the waveforms is organized about a prominent cyclical event with all similar events aligning in approximately the same vertical plane. The system intensifies portions of each trace to produce a three-dimensional contour effect. The resultant display called a contourogram tends to suppress cycle-to-cycle redundancies and to emphasize cycle-to-cycle differences which increases the ability to visually detect any waveform anomalies representative of an abnormality associated with the signal source. Real time display of a single, full cycle of the signal on one horizontal base line, even where no prominent or detectable signal excursion marks the beginning on one cycle and the end of the preceding cycle is effected by keying the oscilloscope sweep trace for the beginning of the real time cycle to a dominant event in the preceding cycle with circuitry which provides a delay between the occurrence of the signaling event and the initiation of the sweep for forming the following, real time trace.

Claims

1. In a contourograph system for processing periodic or semiperiodic input signals to produce a real time video display in a variable persistence oscilloscope, the improvement comprising:

detection means for detecting a first recurring event in a first cycle of periodic or semiperiodic input signal and forming a detector output signal indicative of the presence of said first event;

delay means connected with and responsive to said detection means for initiating a delay output signal at a fixed delay time following occurrence of said detector output signal, said delay means providing a delay time interval which terminates at the end of the waveform in said first cycle and before the onset of the waveform in said first cycle and before the onset of the waveform in said second cycle whereby a complete real time waveform for only one cycle of said input is formed by said oscilloscope traces, and is indicative of instantaneous heartbeat rate;

display control means connected with said detection and delay means for initiating formation of a trace producing sweep signal representing the X-axis input in said oscilloscope upon the occurrence of said delay output signal whereby said sweep occurs substantially simultaneously with the occurrence of a second, later cycle in said input signal to produce a real time oscilloscope trace of the waveform of said second cycle;

intensity control circuit means for providing a Z-axis input to the oscilloscope for varying the intensity of the oscilloscope trace as a function of the input signal amplitude to thereby produce greatest light intensity at the waveform peaks;

summing circuit means for combining said input signal with a repetitive, fixed time duration, amplitude variant signal to produce a Y-axis input for said oscilloscope for producing vertically spaced oscilloscope traces of waveforms in succeeding cycles of said input signal; and

first adjustment means for varying the length of said delay time to permit said system to be adjusted for use with different input signals having varying wavelengths.

2. The contourograph system as defined in claim 1 further including variable persistence control means for adjusting the persistence of said traces whereby the uppermost trace in the sequence of vertical sweeps fades immediately prior to the formation of the first trace of the subsequent sweep.

3. The contourograph system as defined in claim 1 further including:

means for adjusting the horizontal sweep speed of said oscilloscope for operation in a selected one of a slow mode and a fast mode to allow a contourograph display of electrocardiac signals corresponding to a low range of heartbeat rates and a higher range of heartbeat rates, respectively.

4. A contourograph system as defined in claim 1 further including:

a. input signal processing means for amplifying or attenuating said input signal to form a processed signal having amplitude excursions confined between preestablished limits; and

b. filter means included with said input signal processing means for removing undesired frequency components in said input signal.

5. The contourograph system as defined in claim 1 wherein said detector means includes means for detecting the QRS complex in an electrocardiac signal.