Electrocardiogram is displayed as a contourogram on the cathode ray tube of a variable-persistence oscilloscope. Each cycle is stacked below its predecessors giving a three dimensional effect. A major change in the signal is apparent as a change in the contourogram pattern

Golden, D. P., Jr.

Maudlin, D. G.

Wolthuis, R. A.

English

NASA Technical Reports Server

February
 1970	 Brief 70-10030 
S	 NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
••___ __•••_____•__	 _.	
-. Wjpm 
Contourograph Display System for Monitoring Electrocardiograms 
Figure 1, ECG Contourogram 
A visual display system has been devised for the 
real-time presentation of an electrocardiogram (ECG) 
in a highly informative manner. The ECG is displayed 
as a contourogram on the cathode ray tube (CRT) of 
a variable-persistence oscilloscope. Each individual 
cycle of the ECG is stacked below its predecessors as 
shown in Figure 1. Minor cycle-to-cycle variations in 
the ECG contribute to the three-dimensional contour 
effect; a major change in the signal is immediately 
apparent as a change in the contourograin pattern.
The three-dimensional effect is accentuated by dynam-
ically modulating the intensity of the trace so that the 
peaks of the ECG are brighter than the baseline. 
The contourograph system converts a single scalar 
ECG signal into three orthogonal voltages for the 
horizontal, vertical, and z-axis inputs of the variable-
persistence oscilloscope. A block diagram of the real-
time contourograph is shown in Figure 2. The ampli-
fier-filter allows the signal amplitude to be adjusted 
and the high frequencies to be attenuated at 30, 50, or 
Continued overleaf) 
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https://ntrs.nasa.gov/search.jsp?R=19700000029 2020-03-16T23:59:52+00:00Z
100, Hz. The ECG from the amplifier is summed with 
the vertical-sweep sawtooth wave, and the resultant 
waveform is fed to the vertical input of the oscilloscope. 
The Schmitt trigger, monostable multivibrator, and 
horizontal sweep circuit synchronize the contourogram 
so that only one ECG cycle appears on each line and 
corresponding waveforms of succeeding cycles are 
properly aligned. Besides the three horizontal sweep 
speeds for contourography, a fourth speed for standard 
clinical display is also available. The z-axis circuitry 
modulates the intensity of the trace to give the con-
tourogram its three-dimensional quality. Since each 
trace displays only one ECG cycle, the end point of the 
trace implies a value of instantaneous heartrate. A 
sliding scale is affixed to the oscilloscope CRT so that 
heartrates from 30 to 180 beats per minute can be 
determined. 
Amplifier	 L___	 i	
Schmitt 
Filter	 Trigger
In a monitoring scheme the real-time contourogram 
would present information about the patient's cardiac 
condition in an easily assimilated form. Dramatic 
changes in the display would alert the observer to 
abnormal patient conditions. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Manned Spacecraft Center, Code BM7 
Houston, Texas 77058 
Reference: TSP70-10030	 - 
Patent status: 
No patent action is contemplated by NASA. 
Source: D. P. Golden, Jr., D. G. Maudlin, and 
R. A. Wolthuis of 
Technology Incorporated 
under contract to 
Manned Spacecraft Center 
(M SC- 13407) 
	
Monostable I	 I	 Horizontal M.V.	 I	 Time Base 
Z- Axis
	 Z-Out 
Circuitry 
Vertical	 I	 •	 I Summer Sweep	 I	 I
L-Axis 
Y-Out	 I Vert.	 Hon 
IOscilloscope 
Figure 2. Block Diagram of Contourograph 
Brief 70-10030	 Category 05


Contourograph display system for monitoring electrocardiograms

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