- Email: [email protected]
Pocket calculator program to compute normal values for echocardiographic measurements in children
Compuf. Biof. hfrd. Vol. II. No Printed in Grear Bntain.
0010~4825/81/030161~0550200/O Q 1981 Pergamon Press Ltd.
1, pp 161 165. IYXI
POCKET CALCULATOR PROGRAM TO COMPUTE NORMAL VALUES FOR ECHOCARDIOGRAPHIC MEASUREMENTS IN CHILDREN* LARRYA. LATSONand HOWARDP. GUTGESELL The Lillie Frank
Abercrombie
Section of Cardiology, Department of Pediatrics, Medicine, and Texas Children’s Hospital, Houston, Texas. U.S.A. (Received 27 October
Baylor College of
1980)
Abstract-We have developed a pocket calculator program which computes the upper and lower limits of normal for six cardiac dimensions and two systolic time intervals frequently measured from M-mode echocardiograms. The parameters include the diameter of the left ventricle, left atrium. aorta, and right ventricle, the thickness of the septum and left ventricular posterior wall, and the preejection period and ejection time. The normal ranges are calculated from previously published regression equations relating the various parameters to a function of body weight or to heart rate. Use of the program eliminates the necessity for plotting measured values onto graphs of normals, and should increase the speed and accuracy of interpretation of these paremeters, especially in pediatric echocardiography. Pediatrics
Echocardiography
Pocket Calculator
Normal
Values
NOMENCLATURE Entry variables wt body weight (entered in pounds and then converted to kilograms) R-R the interval between successive R waves of the EKG Calculated variables
(A) Dimensions LVEDD left ventricular end diastolic diameter? L,4 left atria1 diameter: AQ aortic diameterf RV right ventricular diastolic diametert SEPT diastolic thickness of the septumt LVPW diastolic thickness of the posterior wall of the LVt (B) Systolic Time Intervals (STI’s) PEP pre-ejection period (measured from the onset of the Q wave of the ECG to the opening of the aortic valve) ET ejection time (measured from the opening point of the aortic valve to the closing point) All dimension measurements are in millimeters and time measurements are in seconds.
t hleasured $ Measured
at the onset of the QRS of the ECG. at the point of maximal anterior excursion
of the aorta.
* Supported in part by Grant HL-07190 From the National Institutes Service and by USPH Grant RR-l 1088 from General Clinical Research
161
of Health, United States Public Health Branch National Institutes of Health.
LARRY
162
A.
LATSON
and HOWARD P. GUTGESELL
INTRODUCTION A major difficulty in interpreting echocardiographic data from children is that dimension measurements and systolic time intervals vary in a non-linear fashion with increasing body size and decreasing R-R interval. To interpret the echocardiogram from a pediatric patient, therefore, the clinician must plot each of the measured cardiac dimensions on an appropriate graph of normal values. This process is both time consuming, and, to some degree, inaccurate. We have developed a program which can be used on a TI 58C or TI 59 pocket calculator to compute the upper and lower limits of normal for six cardiac dimensions and two systolic time intervals after the weight and heart rate are entered. PROGRAM
DESCRIPTION
The echocardiographic indices and systolic time intervals are calculated regression equations published by Gutgesell et al. [ 1, 21 as shown below : LVEDD LA A0 RV SEPT LVPW
= 6.3 = 3.02 = -0.33 = 4.82 = 0.32 = 0.16
PEP ET
= =
$21.65 (log wt) + 14.04 (log wt) + 7.11 3Jwt + 2.5 3Jwt + 2.33 3Jwt + 2.34 3Jwt
0.10 0.389-
0.00028 (HR) 0.00134 (HR)
SEE SEE SEE SEE SEE SEE
= = = = = =
using the
2.83 2.72 2.31 2.65 1.05 1.02
SEE = 0.008 SEE = 0.022
The program makes use of the fact that all the equations are of the general form Y = B + AX. When the coefficients A and B are supplied, the value of Y (where Y equals a dimension or STI) can be found for any X (where X = log weight, 3Jwt, or heart rate). Ninety-five percent of the normal values will lie within +2 SEE of this Y value. For each index, the coefficients and the SEE are stored in three sequential data registers. When one of the labeled keys designating a parameter is pressed, the position if the first of these three data registers is transferred to register 00. The appropriate value of X is determined, and then execution is shifted to the calculation segment of the program. This segment uses indirect addressing of the appropriate data register as indicated by register 00 to obtain the value of A, B, and SEE in successive calculations. To use the program, one first enters the patient’s weight in pounds and then presses the key labeled A. The weight is converted to kilograms and displayed. The user then enters the R-R interval in seconds and presses A’. The heart rate is calculated and displayed. Pressing any other of the labeled keys will then result in calculation of the upper limit of normal for the indicated parameter. Pressing the R/S key then results in the appearance of the lower limit of normal for that parameter (designated by a minus sign in front of the value). Continuing to press the R/S key results in alternate display of the upper and lower limits for that parameter. Because the program requires that a large number of constants (coefficients and SEE’s) be stored in memory before the program can be run, a short optional program to aid in the entry of these values is also presented. This program prompts the user to enter the data into sequential data registers. After each entry, the number of the next data register is shown in the display. This data entry need only be done once if the data is stored on a magnetic card available for the TI 59, but would be needed each time the data registers are changed by another program on the TI 58C. DISCUSSION Echocardiographic dimensions in children are meaningless unless they are compared to normals for age. For instance, an LVEDD of 30 mm may be normal for a child who weighs forty pounds, but would indicate LV dilation in an infant weighing only twelve pounds. Several authors have studied groups of normal children in an effort to establish normal values [l-4]. The best correlations for most echo dimensions have been obtained when the parameters have been indexed to body surface area, height, weight, log weight, or cube root of
Pocket
calculator
program
to compute
echocardiographic
measurements
163
weight. Estimation of body surface area necessitates either a complex calculation or reference to a nomogram, and in many clinical situations, a patient’s height may not be accurately known. In our laboratory we have found that the correlation of echo dimensions with either the log of the weight or cube root of the weight is quite satisfactory [ 1,2]. Using data from 145 normal children, we have previously plotted straight line graphs of weight (plotted on a logarithmic or cube root scale) vs each of the echo dimensions. Each graph displays the mean regression line and the upper and lower limits of 95:; of the normal population. Similar graphs of the STI’s versus HR have also been prepared. For all echocardiograms done, each of the echo measurements must be plotted on the appropriate graph to determine whether it is within the range of normal for the patient’s weight or heart rate. This process is time consuming and often inaccurate unless unusual care is exercised. We developed this program to automatically calculate the upper and lower limits of normal for eight of the most commonly measured parameters from the echocardiogram. The echocardiographer, therefore, does not have to rely on the availability of multiple graphs, and interpretation can be easily made at the patient’s bedside if necessary. SUMMARY We have developed a program to calculate the upper and lower limits of normal for six echocardiographic dimensions and two systolic time intervals. Use of the program eliminates the necessity for plotting each of these measured parameters on a graph of normal values to determine whether the measured value obtained falls within the range of normal for body weight or heart rate. The program should be useful to pediatric cardiologists and also to adult cardiologists who ocasionally see pediatric patients. REFERENCES 1. H. P. Gutgesell, M. Paquet, D. F. Duff, D. G. McNamara, Evaluation of left ventricular size and function by echocardiography. Circulation 56, 457-462 (1977). 2. H. P. Gutgesell, M. Paquet, Atlas of pediatric echocardiography. Harper and Row. London (1978). 3. S. J. Goldberg, H. D. Allen and D. Sahn, Pediatric and Adolescenr Echocardiography---A Handbook. Year Book Medical Publishers, (1975). 4. N. R. Lundstrom, Echocardiography in Congenital Heart Disease. ElsevierNorth-Holland Biomedical Press, Amsterdam (1978).
LARRY A. LATS~N and HOWARD
164
P.GCTMSELI
APPENDIX PROCQAY FOR 71 Tit 1s
Echo
Pr0grnl7QWr
1
2 1 3 1 9
i
1
2
1
9
Library
Propram
calculates R-R
Optional By main
the
interval
- Program proqem.
upper
and
are
input.
allows
rapid
lover
entry
limits
of
of
coefficients
for
and
Enter
weieht
2. 3.
Enter
R-R
interval
Press
any
other
Press
in
L%,
into
LV,
RI’,
SEPT.
sequential
seconds
1980 -
Nr
in
lbs
R-R
Cards
R/S
PEP,
m,
rqisters
s
2n d CO r
key
LVPU,
dara
-RES
ENTER Ut
labeled
Printer
STRUCTIONS
munds in
AO.
SEE’s
PROCEDURE
1.
nacter
1
&en
as
required
Wt in Heart
hp Rate
D..
Upper
limit
R/S
for parameter Lover limir normal
6.
Repeat
steps
values
are
redisplay
upper
and
lower
limits
if
:R/S
necessary)
normal
parameter
(desipnaced (To
body
DISPLAY A A
for 5.
___
DESCRIPTIOH
normal
USER STE
Uodulr
of
October
Date
PROGRAM
WC and
1
Page
Lateon
Partitioning
4.
SBC
Comnurer
(Upper limits
by
-
)
and lover alternately
displayed)
Optional
-
3 and
L until1
to
enter
1.
BeRin
this
2. 3.
Enter Enter
the 1st
1st repister Coefficient
4.
Enter
next
.coefficienr
5.
Repeat
step
proersm
1, until
USER DEFINED A
Ueipht
1
R-R
C D E A’ I’
a11
desired
obtained coefficient
and
SEE’s
sepmnt into
a11
ST0 &ich
data
is
data
will
8
R/S
Current
1st
Data Reelatcr coefficient
RIS R/S
Next
coefficient
R/S
1st Data Rqister Next Data ReRisrer Data Register
1st
DATA REGISTERS 0
IND Address
10
6.3
1
VT
11
2.83
A0 IA LV
2 3 4
HR
12 13 14
2.5 L.82 2.65
R” SEP?.
5 6
15 16
2.33 0.32
interval
(sets)
Next
entered
KEYS
(pounds)
of
value
-
7. I1 0.33
A0
2.31 10.04
C’
LVPC’
7
3.02
D’ E’
PEP ET
8 9
2.72 21.65
LA
17
1.05
18 19 -
2.34 0.16
LV
20 21
RV
SEPT
LVPU
1.02 -
0.00028
22 23 24 -
0.10 0.008 0.0013L
PEP
25 26
0.389 0.022
ET
00 I
Pocket
z
KEY
COFMENTS
61
x
13
RCL 00
IND
69
2nd
OP
20
20
00
85 13 69
2nd
20 85 2
20 +
65
95 94 91 I.0 29 Y1 61 00 27 76 I1 55 2 93 2 YS 42 01 91 76 lb 35 65 6 0 91 42 02 91 76 -12
OP
42
STD
00
00
43 01 22 45 03 95 61
it i
$coo 00
--ET-
02
RCL 02
RCL
61
CT0
01
00 00
00 00
YX
76
LBL
3 -
10 02 04 61
E’ 2 4 CT0
43
INV
1 15
CT0 1:ZC
00
01
01
X RCL
76
LBL
09
09
13 06
C 6
61
CT0
76
00
00
IND
00 .
Upper Limi Displayed
4 X RCL
00 _ + TilS EXC 29 R/S CT0 00 21 LBL A + 2 2 _ ST0 01 RIS LBL A' I/X X
IND Lower
Displayed
76
76
LBL
14
D
9
9
:onvert
WC.
‘o 7 ,tore
O”“ert o H.R. tore 43-52)
6
R-R and
0 5-3-66)
1: 35
Routine
ST0
Enter
43
RCL
Efficient.
00
00
SEE(130-147
R/S ST0
Enter
00 43
00 RCL
91 72
R/S ST0
00
00
69 20
2nd 20
43
RCL 00
01
28 61
LOG CT0
00
00 00
1110
00
LBL
15 01 02
E
61
CT0 00
91 %4-90)
1 2
56
56
76
LBL
SEPT
17 01
I’ 1
(91-91)
05 61
5 CT0
00
00
56 lb 1.9
LIIL C'
61
R/S CT0
01 38
01 38
First
Regisrer
INI
1
08 61 00
8 CT0 00
OP Display6 Register4 enter tppropriate hefficient
LVPY (98-104)
56
LBL 0' 2
PEP (105-115)
1 ST0
1
Enter First hcfficicnt
56
01
19 02 01 - 42
11r5
To Co-
91 42
DO
59 76
ST0
E3-83
LBL
42
00
DO
(33-42)
1:3C
ST0
01
%6-122)
++7-721
42
00 76
0 _
02 R/S LBL B
Limi
79
COKHENTS
00
DO
R/S
73 00
IND
COHHENTS
3
165
measurements
00
91
65
ine
03
echocardiographic
2
ST0 29
75 04
to compute
00
29
42
hbrout
program
COD ---FEion
CO-321
RCL 00
95
hlculat
l
00
73 00
calculator
-
About the Author-LARRY A. LATWN received his B.S. degree in Biophysics from Trinity University, San Antonio, Texas, and his M.D. degree from Baylor College of Medicine, Houston, Texas. He completed two years of pediatric residency at Baylor and is now completing his third year of Postdoctoral Fellowship in Pediatric Cardiology at Texas Children’s Hospital in Houston. His research activities include studies in echocardiography, developmental ventricular function, and computer applications in cardiology.
About the Author-HowARn P. GUTGESELL obtainedhis B.S., MS.. and M.D. degrees from The University of Wisconsin. He completed pediatric training at The University of Rochester, Rochester, New York, and pediatric cardiology training at Baylor College of Medicine, Houston, Texas. Since 1965 he has been on the faculty at Baylor and is currently Associate Professor in the Department of Pediatrics and Director of the Pediatric Non-invasive Laboratory, Texas Children’s Hospital.
0010~4825/81/030161~0550200/O Q 1981 Pergamon Press Ltd.
1, pp 161 165. IYXI
POCKET CALCULATOR PROGRAM TO COMPUTE NORMAL VALUES FOR ECHOCARDIOGRAPHIC MEASUREMENTS IN CHILDREN* LARRYA. LATSONand HOWARDP. GUTGESELL The Lillie Frank
Abercrombie
Section of Cardiology, Department of Pediatrics, Medicine, and Texas Children’s Hospital, Houston, Texas. U.S.A. (Received 27 October
Baylor College of
1980)
Abstract-We have developed a pocket calculator program which computes the upper and lower limits of normal for six cardiac dimensions and two systolic time intervals frequently measured from M-mode echocardiograms. The parameters include the diameter of the left ventricle, left atrium. aorta, and right ventricle, the thickness of the septum and left ventricular posterior wall, and the preejection period and ejection time. The normal ranges are calculated from previously published regression equations relating the various parameters to a function of body weight or to heart rate. Use of the program eliminates the necessity for plotting measured values onto graphs of normals, and should increase the speed and accuracy of interpretation of these paremeters, especially in pediatric echocardiography. Pediatrics
Echocardiography
Pocket Calculator
Normal
Values
NOMENCLATURE Entry variables wt body weight (entered in pounds and then converted to kilograms) R-R the interval between successive R waves of the EKG Calculated variables
(A) Dimensions LVEDD left ventricular end diastolic diameter? L,4 left atria1 diameter: AQ aortic diameterf RV right ventricular diastolic diametert SEPT diastolic thickness of the septumt LVPW diastolic thickness of the posterior wall of the LVt (B) Systolic Time Intervals (STI’s) PEP pre-ejection period (measured from the onset of the Q wave of the ECG to the opening of the aortic valve) ET ejection time (measured from the opening point of the aortic valve to the closing point) All dimension measurements are in millimeters and time measurements are in seconds.
t hleasured $ Measured
at the onset of the QRS of the ECG. at the point of maximal anterior excursion
of the aorta.
* Supported in part by Grant HL-07190 From the National Institutes Service and by USPH Grant RR-l 1088 from General Clinical Research
161
of Health, United States Public Health Branch National Institutes of Health.
LARRY
162
A.
LATSON
and HOWARD P. GUTGESELL
INTRODUCTION A major difficulty in interpreting echocardiographic data from children is that dimension measurements and systolic time intervals vary in a non-linear fashion with increasing body size and decreasing R-R interval. To interpret the echocardiogram from a pediatric patient, therefore, the clinician must plot each of the measured cardiac dimensions on an appropriate graph of normal values. This process is both time consuming, and, to some degree, inaccurate. We have developed a program which can be used on a TI 58C or TI 59 pocket calculator to compute the upper and lower limits of normal for six cardiac dimensions and two systolic time intervals after the weight and heart rate are entered. PROGRAM
DESCRIPTION
The echocardiographic indices and systolic time intervals are calculated regression equations published by Gutgesell et al. [ 1, 21 as shown below : LVEDD LA A0 RV SEPT LVPW
= 6.3 = 3.02 = -0.33 = 4.82 = 0.32 = 0.16
PEP ET
= =
$21.65 (log wt) + 14.04 (log wt) + 7.11 3Jwt + 2.5 3Jwt + 2.33 3Jwt + 2.34 3Jwt
0.10 0.389-
0.00028 (HR) 0.00134 (HR)
SEE SEE SEE SEE SEE SEE
= = = = = =
using the
2.83 2.72 2.31 2.65 1.05 1.02
SEE = 0.008 SEE = 0.022
The program makes use of the fact that all the equations are of the general form Y = B + AX. When the coefficients A and B are supplied, the value of Y (where Y equals a dimension or STI) can be found for any X (where X = log weight, 3Jwt, or heart rate). Ninety-five percent of the normal values will lie within +2 SEE of this Y value. For each index, the coefficients and the SEE are stored in three sequential data registers. When one of the labeled keys designating a parameter is pressed, the position if the first of these three data registers is transferred to register 00. The appropriate value of X is determined, and then execution is shifted to the calculation segment of the program. This segment uses indirect addressing of the appropriate data register as indicated by register 00 to obtain the value of A, B, and SEE in successive calculations. To use the program, one first enters the patient’s weight in pounds and then presses the key labeled A. The weight is converted to kilograms and displayed. The user then enters the R-R interval in seconds and presses A’. The heart rate is calculated and displayed. Pressing any other of the labeled keys will then result in calculation of the upper limit of normal for the indicated parameter. Pressing the R/S key then results in the appearance of the lower limit of normal for that parameter (designated by a minus sign in front of the value). Continuing to press the R/S key results in alternate display of the upper and lower limits for that parameter. Because the program requires that a large number of constants (coefficients and SEE’s) be stored in memory before the program can be run, a short optional program to aid in the entry of these values is also presented. This program prompts the user to enter the data into sequential data registers. After each entry, the number of the next data register is shown in the display. This data entry need only be done once if the data is stored on a magnetic card available for the TI 59, but would be needed each time the data registers are changed by another program on the TI 58C. DISCUSSION Echocardiographic dimensions in children are meaningless unless they are compared to normals for age. For instance, an LVEDD of 30 mm may be normal for a child who weighs forty pounds, but would indicate LV dilation in an infant weighing only twelve pounds. Several authors have studied groups of normal children in an effort to establish normal values [l-4]. The best correlations for most echo dimensions have been obtained when the parameters have been indexed to body surface area, height, weight, log weight, or cube root of
calculator
program
to compute
echocardiographic
measurements
163
weight. Estimation of body surface area necessitates either a complex calculation or reference to a nomogram, and in many clinical situations, a patient’s height may not be accurately known. In our laboratory we have found that the correlation of echo dimensions with either the log of the weight or cube root of the weight is quite satisfactory [ 1,2]. Using data from 145 normal children, we have previously plotted straight line graphs of weight (plotted on a logarithmic or cube root scale) vs each of the echo dimensions. Each graph displays the mean regression line and the upper and lower limits of 95:; of the normal population. Similar graphs of the STI’s versus HR have also been prepared. For all echocardiograms done, each of the echo measurements must be plotted on the appropriate graph to determine whether it is within the range of normal for the patient’s weight or heart rate. This process is time consuming and often inaccurate unless unusual care is exercised. We developed this program to automatically calculate the upper and lower limits of normal for eight of the most commonly measured parameters from the echocardiogram. The echocardiographer, therefore, does not have to rely on the availability of multiple graphs, and interpretation can be easily made at the patient’s bedside if necessary. SUMMARY We have developed a program to calculate the upper and lower limits of normal for six echocardiographic dimensions and two systolic time intervals. Use of the program eliminates the necessity for plotting each of these measured parameters on a graph of normal values to determine whether the measured value obtained falls within the range of normal for body weight or heart rate. The program should be useful to pediatric cardiologists and also to adult cardiologists who ocasionally see pediatric patients. REFERENCES 1. H. P. Gutgesell, M. Paquet, D. F. Duff, D. G. McNamara, Evaluation of left ventricular size and function by echocardiography. Circulation 56, 457-462 (1977). 2. H. P. Gutgesell, M. Paquet, Atlas of pediatric echocardiography. Harper and Row. London (1978). 3. S. J. Goldberg, H. D. Allen and D. Sahn, Pediatric and Adolescenr Echocardiography---A Handbook. Year Book Medical Publishers, (1975). 4. N. R. Lundstrom, Echocardiography in Congenital Heart Disease. ElsevierNorth-Holland Biomedical Press, Amsterdam (1978).
LARRY A. LATS~N and HOWARD
164
P.GCTMSELI
APPENDIX PROCQAY FOR 71 Tit 1s
Echo
Pr0grnl7QWr
1
2 1 3 1 9
i
1
2
1
9
Library
Propram
calculates R-R
Optional By main
the
interval
- Program proqem.
upper
and
are
input.
allows
rapid
lover
entry
limits
of
of
coefficients
for
and
Enter
weieht
2. 3.
Enter
R-R
interval
Press
any
other
Press
in
L%,
into
LV,
RI’,
SEPT.
sequential
seconds
1980 -
Nr
in
lbs
R-R
Cards
R/S
PEP,
m,
rqisters
s
2n d CO r
key
LVPU,
dara
-RES
ENTER Ut
labeled
Printer
STRUCTIONS
munds in
AO.
SEE’s
PROCEDURE
1.
nacter
1
&en
as
required
Wt in Heart
hp Rate
D..
Upper
limit
R/S
for parameter Lover limir normal
6.
Repeat
steps
values
are
redisplay
upper
and
lower
limits
if
:R/S
necessary)
normal
parameter
(desipnaced (To
body
DISPLAY A A
for 5.
___
DESCRIPTIOH
normal
USER STE
Uodulr
of
October
Date
PROGRAM
WC and
1
Page
Lateon
Partitioning
4.
SBC
Comnurer
(Upper limits
by
-
)
and lover alternately
displayed)
Optional
-
3 and
L until1
to
enter
1.
BeRin
this
2. 3.
Enter Enter
the 1st
1st repister Coefficient
4.
Enter
next
.coefficienr
5.
Repeat
step
proersm
1, until
USER DEFINED A
Ueipht
1
R-R
C D E A’ I’
a11
desired
obtained coefficient
and
SEE’s
sepmnt into
a11
ST0 &ich
data
is
data
will
8
R/S
Current
1st
Data Reelatcr coefficient
RIS R/S
Next
coefficient
R/S
1st Data Rqister Next Data ReRisrer Data Register
1st
DATA REGISTERS 0
IND Address
10
6.3
1
VT
11
2.83
A0 IA LV
2 3 4
HR
12 13 14
2.5 L.82 2.65
R” SEP?.
5 6
15 16
2.33 0.32
interval
(sets)
Next
entered
KEYS
(pounds)
of
value
-
7. I1 0.33
A0
2.31 10.04
C’
LVPC’
7
3.02
D’ E’
PEP ET
8 9
2.72 21.65
LA
17
1.05
18 19 -
2.34 0.16
LV
20 21
RV
SEPT
LVPU
1.02 -
0.00028
22 23 24 -
0.10 0.008 0.0013L
PEP
25 26
0.389 0.022
ET
00 I
z
KEY
COFMENTS
61
x
13
RCL 00
IND
69
2nd
OP
20
20
00
85 13 69
2nd
20 85 2
20 +
65
95 94 91 I.0 29 Y1 61 00 27 76 I1 55 2 93 2 YS 42 01 91 76 lb 35 65 6 0 91 42 02 91 76 -12
OP
42
STD
00
00
43 01 22 45 03 95 61
it i
$coo 00
--ET-
02
RCL 02
RCL
61
CT0
01
00 00
00 00
YX
76
LBL
3 -
10 02 04 61
E’ 2 4 CT0
43
INV
1 15
CT0 1:ZC
00
01
01
X RCL
76
LBL
09
09
13 06
C 6
61
CT0
76
00
00
IND
00 .
Upper Limi Displayed
4 X RCL
00 _ + TilS EXC 29 R/S CT0 00 21 LBL A + 2 2 _ ST0 01 RIS LBL A' I/X X
IND Lower
Displayed
76
76
LBL
14
D
9
9
:onvert
WC.
‘o 7 ,tore
O”“ert o H.R. tore 43-52)
6
R-R and
0 5-3-66)
1: 35
Routine
ST0
Enter
43
RCL
Efficient.
00
00
SEE(130-147
R/S ST0
Enter
00 43
00 RCL
91 72
R/S ST0
00
00
69 20
2nd 20
43
RCL 00
01
28 61
LOG CT0
00
00 00
1110
00
LBL
15 01 02
E
61
CT0 00
91 %4-90)
1 2
56
56
76
LBL
SEPT
17 01
I’ 1
(91-91)
05 61
5 CT0
00
00
56 lb 1.9
LIIL C'
61
R/S CT0
01 38
01 38
First
Regisrer
INI
1
08 61 00
8 CT0 00
OP Display6 Register4 enter tppropriate hefficient
LVPY (98-104)
56
LBL 0' 2
PEP (105-115)
1 ST0
1
Enter First hcfficicnt
56
01
19 02 01 - 42
11r5
To Co-
91 42
DO
59 76
ST0
E3-83
LBL
42
00
DO
(33-42)
1:3C
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About the Author-LARRY A. LATWN received his B.S. degree in Biophysics from Trinity University, San Antonio, Texas, and his M.D. degree from Baylor College of Medicine, Houston, Texas. He completed two years of pediatric residency at Baylor and is now completing his third year of Postdoctoral Fellowship in Pediatric Cardiology at Texas Children’s Hospital in Houston. His research activities include studies in echocardiography, developmental ventricular function, and computer applications in cardiology.
About the Author-HowARn P. GUTGESELL obtainedhis B.S., MS.. and M.D. degrees from The University of Wisconsin. He completed pediatric training at The University of Rochester, Rochester, New York, and pediatric cardiology training at Baylor College of Medicine, Houston, Texas. Since 1965 he has been on the faculty at Baylor and is currently Associate Professor in the Department of Pediatrics and Director of the Pediatric Non-invasive Laboratory, Texas Children’s Hospital.