J. ELECTROCARDIOLOGY 10 (4), 1977, 393-395
Instrumentation:
Direct-Writing Color Vectorcardiograph BY SHINJI KINOSHITA, M.D., KUMIKO SUZUKI, M.D., HARUO HIRAKI AND SHUZO ITO
jected on a f l u o r e s c e n t s c r e e n of t h e c a t h o d e r a y oscilloscope w a s p h o t o g r a p h e d t h r o u g h a filter for coloring b y t h e u s e of color film. I n t h e p r e s e n t p a p e r a n e w m e t h o d is described, by w h i c h t h e color is w r i t t e n d i r e c t l y on t h e recording paper.
SUMMARY By employing a specially designed instrument, a "color vectorcardiogram," a single, colored horizontal plane vectorcardiogram (VCG) was written directly on the recording paper. At first, the voltage in the X, Y and Z axes was memorized into the digital memory cells. After that, the voltage in the X and Z axes was slowly read out so that a horizontal plane vectorcardiogram was written directly on the paper of the X-Y recorder. The color of the recording pen varied according to the voltage in the Y axis, which was read out simult a n e o u s l y with the voltage in the X and Z axes. T h e '~color v e c t o r c a r d i o g r a m ''1-3 is a single, colored, horizontal plane VCG in which s u p e r i o r - i n f e r i o r (Y axis) deflections a r e repr e s e n t e d in t h e f o r m of colored dashes. I n t h e o r i g i n a l m e t h o d d e v i s e d by K i n o s h i t a a n d K o b a y a s h i for r e c o r d i n g t h e color V C G , 1 a m o n o c h r o m a t i c h o r i z o n t a l p l a n e V C G pro-
MATERIALS AND METHODS An outline of the direct writing color vectorcardiograph is illustrated in Fig. 1. At first the voltage in the X, Y and Z axes, obtained according to the F r a n k lead, was memorized into the digital memory cells. After that, the voltage in the X and Z axes was slowly read out so that a horizontal plane VCG was written directly on the paper of the X-Y recorder. Ten pens with different colors were set in a columnar pen head of the X-Y recorder as shown in Fig. 2. These color pens touched the recording paper one at a time. The servomechanism rotated the pen head according to the voltage in the Y axis which was read out simultaneously with the voltage in the X and Z axes. Thus the color of the pen touching the recording paper varied according to the voltage in the Y axis. Dashes of the vector loop were directly written with color pens as follows: dashes at the level of the origin, with a yellow pen; those higher t h a n the origin (that is, in the direction of the head, or in the positive direction), with reddish pens; and those lower than the origin (that is, in the footward or negative direction), with bluish pens. In the usual sensitivity to the voltage in the Y axis, dashes higher than + 1.6 mv and dashes lower t h a n - 2.4 mv were all written with a black pen. In cases showing such a large Y axis magnitude, the sensitivity to the voltage in the Y axis was decreased to half the usual sensitivity. Conversely, in cases showing an unusually small Y axis magnitude, the sensitivity was increased to twice the usual one.
From the Second Department of Medicine and the Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Sapporo; and the Medical Electronics Division, San-ei Instrument Company, Tokyo; Japan. Supported in part by a grant from the Education Ministry of the Japanese Government. Reprint requests to: Shinji Kinoshita., M.D., the Second Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan. 393
394
~4emoryl Ic°mpa-I |Color Matrixl 7/I Amp. l\ I -Y I--->Irator I--->I (8) I ?ra~ / ~'~naio-' ~ I I (7) ] | . , I :Net ~ l - - - > ~ - - > ~ u i ti -~I---~~IMe m° rYl--->~ - ~ . % , -X J '- -~ Servo-amp " Work I Amp • I lexe W°-rkl ~ ~ "[(4)I~ (6) / I (9) I (i) J ~ ~ / ' |
(3)~en | U
D
1;5~Memor~--~?l
P-°wnl IX-Y Rec~rderl~'-I Pen. Head Controller --> ... I I (Iu)
I~"
L
]I
I**,
,
I I
-
Fig. 1. Block diagram of the direct writing color vectorcardiograph. The instrument consists mainly of the following parts: (1) a resistance network of Frank; (2) A.C. amplifiers of the voltage in the X, Y and Z axes; (3) an analog multiplexer; (4) an analog-to-digital converter of the successive approximation type; (5) digital memories of the random access type for the X, Y and Z scalars; (6) digital-to-analog converters; (7) a digital comparator which converts the contents of the memory into a color code; (8) a color matrix which generates voltage according to the color code; (9) a servo-amplifier which controls the angle of rotation of the pen head; (10) a pen angle detector with the pen head; (11) an X-Y recorder; and (12) a pen up-down controller which lifts up the pen from the recording paper when the pen head rotates.
RESULTS F i g u r e 3 shows a n e x a m p l e of t h e color vect o r c a r d i o g r a m w r i t t e n directly on paper, recorded from a 68 y e a r old w o m a n w i t h a n g i n a pectoris by e m p l o y i n g the a b o v e - m e n t i o n e d i n s t r u m e n t . In this examp]e, the s e n s i t i v i t y to the voltage in the Y axis is increased to twice the u s u a l sensitivity. The QRS loop shows counterclockwise rota-
tion. First, t h e loop s t a r t i n g from the origin (yellow) goes d o w n w a r d t h r o u g h bluish colors to a d e p t h o f b l u i s h p u r p l e ( - 1 . 0 m v in height), which r e p r e s e n t s the m a x i m u m QRS v e c t o r projecting downward, to the left and slightly a n t e r i o r l y . T h e n , the loop goes upw a r d t h r o u g h b l u i s h colors to t h e same level as t h e origin (yellow). The loop c o n t i n u e s to go u p w a r d t h r o u g h r e d d i s h colors to a h e i g h t of r e d d i s h p u r p l e ( + 0 . 6 mv). F i n a l l y , the QRS
Fig. 2. Columnar pen head, 23 mm in diameter and 20 mm in height, in which ten color pens are set.
J. ELECTROCARDIOLOGY,VOL. 10, NO. 4, 1977
395
loop a g a i n goes d o w n w a r d , and, p a s s i n g through reddish colors, terminates at a point on the same level as the origin (yellow), although this point is distant from the origin, representing an open QRS loop.
DISCUSSION The color vectorcardiogram, i.e., a single plane color vectorcardiogram, represents a spatial VCG. By using color, we have attempted to facilitate interpretation of the vectorcardiogram. 1-3 In the original method, the color VCG was photographed on color film through a filter for coloring. Accordingly, this original method had disadvantages, as the process of developing and printing the color photograph takes considerable time and produced a considerable change in color. By
employing the i n s t r u m e n t described in the present paper, the color vectorcardiogram is written directly on the paper. As the result, t h e d i s a d v a n t a g e s of t h e o r i g i n a l m e t h o d are e l i m i n a t e d and clinical application of the color vectorcardiogram can be f u r t h e r facilitated. REFERENCES 1. KINOSHITA,S ANDKOBAYSHI,T: "Color vectorcardiogram" recorded with a specially designed apparatus for spatial representation by coloring. Circulation 54:534, 1971 2. KINOSHITA,S AND KOBAYASHI,T: "Color vectorcardiograms" recorded in 2 cases of inferior myocardial infarction. Am J Cardiol 31:796, 1973 3. KINOSHITA,S, KOBAYASHI,T AND TAKAHASHI, K: Color vectorcardiograms recorded in two unusual cases. Chest 65:673, 1974
Back Head Oabove 0+0.6
+ 0.8
@+0.4 0+0.2 00
S
\
mv
0-0.2 0-0.4 0-0.6 0-o.8 0-1.o Obelow Foot
\
4 `¸
\
Right
Le
\ - 1.2
\
....
!
1 mv Front Fig. 3. An example of the color vectorcardiogram written directly on the recording paper. Each interval between dashes represents 2 msec.
J. ELECTROCARDIOLOGY, VOL. 10, NO. 4, 1977
Instrumentation:
Direct-Writing Color Vectorcardiograph BY SHINJI KINOSHITA, M.D., KUMIKO SUZUKI, M.D., HARUO HIRAKI AND SHUZO ITO
jected on a f l u o r e s c e n t s c r e e n of t h e c a t h o d e r a y oscilloscope w a s p h o t o g r a p h e d t h r o u g h a filter for coloring b y t h e u s e of color film. I n t h e p r e s e n t p a p e r a n e w m e t h o d is described, by w h i c h t h e color is w r i t t e n d i r e c t l y on t h e recording paper.
SUMMARY By employing a specially designed instrument, a "color vectorcardiogram," a single, colored horizontal plane vectorcardiogram (VCG) was written directly on the recording paper. At first, the voltage in the X, Y and Z axes was memorized into the digital memory cells. After that, the voltage in the X and Z axes was slowly read out so that a horizontal plane vectorcardiogram was written directly on the paper of the X-Y recorder. The color of the recording pen varied according to the voltage in the Y axis, which was read out simult a n e o u s l y with the voltage in the X and Z axes. T h e '~color v e c t o r c a r d i o g r a m ''1-3 is a single, colored, horizontal plane VCG in which s u p e r i o r - i n f e r i o r (Y axis) deflections a r e repr e s e n t e d in t h e f o r m of colored dashes. I n t h e o r i g i n a l m e t h o d d e v i s e d by K i n o s h i t a a n d K o b a y a s h i for r e c o r d i n g t h e color V C G , 1 a m o n o c h r o m a t i c h o r i z o n t a l p l a n e V C G pro-
MATERIALS AND METHODS An outline of the direct writing color vectorcardiograph is illustrated in Fig. 1. At first the voltage in the X, Y and Z axes, obtained according to the F r a n k lead, was memorized into the digital memory cells. After that, the voltage in the X and Z axes was slowly read out so that a horizontal plane VCG was written directly on the paper of the X-Y recorder. Ten pens with different colors were set in a columnar pen head of the X-Y recorder as shown in Fig. 2. These color pens touched the recording paper one at a time. The servomechanism rotated the pen head according to the voltage in the Y axis which was read out simultaneously with the voltage in the X and Z axes. Thus the color of the pen touching the recording paper varied according to the voltage in the Y axis. Dashes of the vector loop were directly written with color pens as follows: dashes at the level of the origin, with a yellow pen; those higher t h a n the origin (that is, in the direction of the head, or in the positive direction), with reddish pens; and those lower than the origin (that is, in the footward or negative direction), with bluish pens. In the usual sensitivity to the voltage in the Y axis, dashes higher than + 1.6 mv and dashes lower t h a n - 2.4 mv were all written with a black pen. In cases showing such a large Y axis magnitude, the sensitivity to the voltage in the Y axis was decreased to half the usual sensitivity. Conversely, in cases showing an unusually small Y axis magnitude, the sensitivity was increased to twice the usual one.
From the Second Department of Medicine and the Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Sapporo; and the Medical Electronics Division, San-ei Instrument Company, Tokyo; Japan. Supported in part by a grant from the Education Ministry of the Japanese Government. Reprint requests to: Shinji Kinoshita., M.D., the Second Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan. 393
394
~4emoryl Ic°mpa-I |Color Matrixl 7/I Amp. l\ I -Y I--->Irator I--->I (8) I ?ra~ / ~'~naio-' ~ I I (7) ] | . , I :Net ~ l - - - > ~ - - > ~ u i ti -~I---~~IMe m° rYl--->~ - ~ . % , -X J '- -~ Servo-amp " Work I Amp • I lexe W°-rkl ~ ~ "[(4)I~ (6) / I (9) I (i) J ~ ~ / ' |
(3)~en | U
D
1;5~Memor~--~?l
P-°wnl IX-Y Rec~rderl~'-I Pen. Head Controller --> ... I I (Iu)
I~"
L
]I
I**,
,
I I
-
Fig. 1. Block diagram of the direct writing color vectorcardiograph. The instrument consists mainly of the following parts: (1) a resistance network of Frank; (2) A.C. amplifiers of the voltage in the X, Y and Z axes; (3) an analog multiplexer; (4) an analog-to-digital converter of the successive approximation type; (5) digital memories of the random access type for the X, Y and Z scalars; (6) digital-to-analog converters; (7) a digital comparator which converts the contents of the memory into a color code; (8) a color matrix which generates voltage according to the color code; (9) a servo-amplifier which controls the angle of rotation of the pen head; (10) a pen angle detector with the pen head; (11) an X-Y recorder; and (12) a pen up-down controller which lifts up the pen from the recording paper when the pen head rotates.
RESULTS F i g u r e 3 shows a n e x a m p l e of t h e color vect o r c a r d i o g r a m w r i t t e n directly on paper, recorded from a 68 y e a r old w o m a n w i t h a n g i n a pectoris by e m p l o y i n g the a b o v e - m e n t i o n e d i n s t r u m e n t . In this examp]e, the s e n s i t i v i t y to the voltage in the Y axis is increased to twice the u s u a l sensitivity. The QRS loop shows counterclockwise rota-
tion. First, t h e loop s t a r t i n g from the origin (yellow) goes d o w n w a r d t h r o u g h bluish colors to a d e p t h o f b l u i s h p u r p l e ( - 1 . 0 m v in height), which r e p r e s e n t s the m a x i m u m QRS v e c t o r projecting downward, to the left and slightly a n t e r i o r l y . T h e n , the loop goes upw a r d t h r o u g h b l u i s h colors to t h e same level as t h e origin (yellow). The loop c o n t i n u e s to go u p w a r d t h r o u g h r e d d i s h colors to a h e i g h t of r e d d i s h p u r p l e ( + 0 . 6 mv). F i n a l l y , the QRS
Fig. 2. Columnar pen head, 23 mm in diameter and 20 mm in height, in which ten color pens are set.
J. ELECTROCARDIOLOGY,VOL. 10, NO. 4, 1977
395
loop a g a i n goes d o w n w a r d , and, p a s s i n g through reddish colors, terminates at a point on the same level as the origin (yellow), although this point is distant from the origin, representing an open QRS loop.
DISCUSSION The color vectorcardiogram, i.e., a single plane color vectorcardiogram, represents a spatial VCG. By using color, we have attempted to facilitate interpretation of the vectorcardiogram. 1-3 In the original method, the color VCG was photographed on color film through a filter for coloring. Accordingly, this original method had disadvantages, as the process of developing and printing the color photograph takes considerable time and produced a considerable change in color. By
employing the i n s t r u m e n t described in the present paper, the color vectorcardiogram is written directly on the paper. As the result, t h e d i s a d v a n t a g e s of t h e o r i g i n a l m e t h o d are e l i m i n a t e d and clinical application of the color vectorcardiogram can be f u r t h e r facilitated. REFERENCES 1. KINOSHITA,S ANDKOBAYSHI,T: "Color vectorcardiogram" recorded with a specially designed apparatus for spatial representation by coloring. Circulation 54:534, 1971 2. KINOSHITA,S AND KOBAYASHI,T: "Color vectorcardiograms" recorded in 2 cases of inferior myocardial infarction. Am J Cardiol 31:796, 1973 3. KINOSHITA,S, KOBAYASHI,T AND TAKAHASHI, K: Color vectorcardiograms recorded in two unusual cases. Chest 65:673, 1974
Back Head Oabove 0+0.6
+ 0.8
@+0.4 0+0.2 00
S
\
mv
0-0.2 0-0.4 0-0.6 0-o.8 0-1.o Obelow Foot
\
4 `¸
\
Right
Le
\ - 1.2
\
....
!
1 mv Front Fig. 3. An example of the color vectorcardiogram written directly on the recording paper. Each interval between dashes represents 2 msec.
J. ELECTROCARDIOLOGY, VOL. 10, NO. 4, 1977
