Echocardiographic indices in the normal dog - [1983] June Boon

Prévia do material em texto

ECHOCARDIOGRAPHIC INDICES IN THE NORMAL DOG 
JUNE BOON, MS, WAYNE E. WINGFIELD, DVM, MS, CHARLES W. MILLER, PHD 
Twenty young healthy dogs weighing from 9.8 to 28.6 kg were studied by M-mode echocardiog- 
raphy. Parameters were measured and statistically evaluated to determine whether a correlation 
to body surface area existed. A statistically significant correlation to body size was found for the 
aortic, left atrial, left ventricular, septal, and posterior wall dimensions and the mitral valve 
amplitude of motion. In addition, normal values not correlated to body surface area are presented 
with their means and standard deviations. These values include velocity of circumferential fiber 
shortening, ejection time, percent systolic thickening of septum and posterior wall, percent change 
in minor diameter, selected dimension ratios, and mitral valve velocities. Veterinary Radiology, 
Vol. 24, NO. 5 , 1983; p p 214-221. 
Key words: M-mode echocardiography, dog. 
CHOCARDIOGRAPHY plays a major role in the as- E sessment of cardiac disorders in humans but has 
not acquired such significance in veterinary medicine. 
This is partly due to the fact that clinical usefulness 
requires documentation of normal echocardiographic 
measurements. The present paper provides M-mode 
parameters for cardiac size and function in normal un- 
sedated dogs and relates them to body surface area. 
The literature contains several reports of echocar- 
diography in the The majority of these reports 
describe cardiac structures associated with an ab- 
normal state that was verified at necropsy; two deal 
with normal Of these two reports, one 
gives values in the anesthetized dog for mitral valve 
motion and aortic dimension,' and the other gives 
mean values in the awake dog for left ventricular di- 
mensions . 2 Measurements from both papers are hard 
to apply in a clinical situation in which dogs are awake 
and range from Toy Poodles to Great Danes. The effect 
of body surface area on cardiac size is reported for 
humans but not for dog^.^-^ 
The present study measured echocardiographically 
derived M-mode parameters and statistically evalu- 
ated them to correlate increasing body size to in- 
creasing cardiac dimension. Statistically significant 
correlation of body surface area to many measure- 
ments was found and allows use of a regression equa- 
tion to determine mean normal values of dimension 
for a given body size. 
From the Department of Physiology and Biophysics (Miller) and 
the Department of Clinical Sciences (Boon, Wingfield), College of 
Veterinary Medicine and Biomedical Sciences, Colorado State Uni- 
versity, Fort Collins, Colorado 80523. 
Supported by Experiment Station Grant #1-59321, Colorado 
State University, Fort Collins, Colorado 80523. 
Address reprint requests to Dr. Wingfield, Department of Clinical 
Sciences, Colorado State University, Fort Collins, Colorado 80523. 
Materials and Methods 
Twenty dogs, eight males and 12 females ranging in 
weight from 9.8 to 28.6 kg (X, 19.3 kg), in age from 6 
months to 6 years (X, 16.4 months), and in body sur- 
face area from 0.49 m2 to 0.94 m2 (X, 0.72 m2), were 
evaluated. Physical examination and a standard ten- 
lead electrocardiogram were normal in all dogs. 
Breeds included two unknown mixes, one Terrier 
cross, one English Setter, one English Springer, three 
Doberman crosses, three Dingo crosses, one Beagle, 
four German Shepherd crosses, three Golden Re- 
triever crosses, and one Dalmatian. 
Body surface area (BSA), in square meters, was de- 
termined for each dog by the following formula,I0 
Km x W2I3 
1 0 4 BSA = 
where weight (W) is expressed in grams and Km is a 
constant (10.1 in the dog). 
M-mode echocardiograms were obtained using a 
3.5-MHz unfocused transducer 6 mm in diameter.? 
Unsedated dogs were placed in left lateral recum- 
bency, and the transducer was placed in the fourth or 
fifth intercostal space. Transducer distance from the 
sternum varied with chest configuration. Thin-chested 
dogs required placement closer to the costochondral 
junction than dogs with broader thoraces. Left lateral 
recumbency places the dog in a relaxed position with 
easy access to the ultrasonic window (Fig. 1). 
Echocardiograms were recorded and measured 
under the guidelines set by the American Society of 
Echocardiography ' with the exception of two aortic 
cusps 'that were difficult to visualize in most cases. 
t Unirad Sonograph-D, Unirad Corporation, Denver, Colorado. 
0196-362718311000102141$0t .20 0 American College of Veterinary Radiology 
214 
VOL. 24, No. 5 ECHOCARDIOGRAPHY IN NORMAL DOGS 215 
FIG. 1. With the dog in left lateral recumbency the transducer is 
placed at the fourth or fifth intercostal space. 
Therefore, most of the aortic and left atrial measure- 
ments were taken when only one cusp was seen. Left 
ventricular measurements were taken at the level of 
the chordae tendinae as suggested for measurement of 
the adult human echocardiogram." Figure 2 shows the 
angles of the ultrasonic beam through the heart at the 
various structures recorded. 
Each dimension was measured at three representa- 
tive cardiac cycles and averaged. In addition, the 
following indices were ~ a l c u l a t e d ' ~ - ' ~ : (1) Percent 
systolic thickening of the interventricular septum- 
calculated as (end-systolic septal thickness minus end- 
diastolic septal thickness divided by end-diastolic 
septal thickness) multiplied by 100. (2) Percent systolic 
thickening of the left ventricular posterior wall-cal- 
culated as (end-systolic wall thickness minus end-di- 
astolic wall thickness divided by end-diastolic wall 
thickness) multiplied by 100. (3)IVS/LVPW-calcu- 
lated as end-diastolic ventricular septal thickness di- 
vided by end-diastolic posterior wall thickness. (4) 
Ejection time-calculated as time from opening to clo- 
sure of the aortic valve. (5) Velocity of circumferential 
fiber shortening-calculated as left ventricular end-di- 
astolic dimension minus left ventricular end-systolic 
dimension divided by (left ventricular end-diastolic di- 
mension multiplied by ejection time). (6) Percent 
change in minor diameter-calculated as (left ventric- 
ular end-diastolic dimension minus left ventricular 
end-systolic dimension divided by left ventricular end- 
diastolic dimension) multiplied by 100. (7) LA/AO- 
calculated as left atrial maximal dimension (taken at 
the time of left ventricular end-systole) divided by the 
aortic dimension (taken at the time of left ventricular 
end-diastole). 
All parameters were statistically evaluated for cor- 
relation to BSA. Regression equations, correlation 
coefficients, and 95% confidence intervals (CI) about 
the regression line were determined for parameters 
that showed a statistically significant (p < .05) rela- 
tion. l6 
Correlation of echocardiographically determined 
parameters to BSA was acknowledged if a 95% CI 
about the slope of the regression line did not include 
zero. The measurements also were analyzed to deter- 
mine percent correlation when plotted versus log of 
BSA, square root of BSA, and cube root of BSA. 
The following parameters were also statistically 
evaluated to determine whether a relation to heart rate 
FIG. 2. By angling the trans- 
ducer from base to apex, the three 
standard positions for an M-mode 
echocardiogram are obtained: (1) 
left ventricle; (2) mitral valve; (3) 
aortic root. 
216 BOON ET AL. 
10 
- 9 - 
E 
E 
3 8 - 
a 
E a 
= 7 - 
- 
0) D 
c ._ - 
5i 
0 .- 
c L 
2 6 - 
L 
0 
0) 
._ 
L 
c : 5 - a 
4 - 
1983 
- existed: mitral valve opening velocity (DE slope), mi- 
tral valve amplitude of motion (DE and CE), mitral 
valve early diastolic closing velocity (EF slope), per- 
cent thickening of the left ventricularposterior wall, 
and percent change in minor diameter of the left ven- 
tricle. 
In humans there is less than 6% difference in cor- 
relation to BSA between males and females.g There- 
fore, separate regression were not performed for the 
two sexes. 
Means, standard deviations, standard errors, 95% 
CI, and ranges were determined for parameters that 
did not show a statistically significant relation to 
Because normal values for several parameters in the 
dog are reported in the literature, Student's t-tests 
were used to compare the mean values with those of 
others. 1,2 
BSA! 
Results 
Echocardiographic indices that showed a statisti- 
cally significant correlation (p < .05) to BSA are il- 
lustrated in Figures 3-14. The echocardiographic pa- 
rameter on the ordinate is plotted as a function of BSA 
on the abscissa. Regression equations, correlation 
coefficients, and 95% CI for the regression lines are 
shown on these graphs. 
Equations necessary to determine these regression 
Y = 
r = 
2.51 + 7.22X 
.62 
40 .50 .60 .70 .80 .90 I .o 
Body Surface Area (meters2) 
FIG. 3. Mean value (y) (mm) for the anterior aortic wall amplitude 
of motion and the 95% confidence interval plotted as a function of 
body surface area (BSA); y is determined from the regression equa- 
tion y = 2.51 + 7.22x, where x is the BSA. The correlation coef- 
ficient (r) is 0.62. 
I 1 I I I I I I 
40 5 0 60 70 80 90 10 
Body Surface Area (meters2) 
FIG. 4. Mean value (y) (mm) for the posterior aortic wall ampli- 
tude of motion and the 95% confidence interval plotted as a function 
of body surface area (BSA); y is determined from the regression 
equation y = 2.92 + 6.35x, where x is the BSA. The correlation 
coefficient (r) is 0.59. 
lines, the variance of the estimate around the regres- 
sion lines, and the 95% CI about the regression lines 
are listed in Table 1. Instructions for use of the table 
are given in the Appendix. 
Parameters for which measurements did not signif- 
icantly correlate the BSA are listed with means, stan- 
dard deviations, standard errors, range, and 95% CIS 
in Table 2. 
27 **OF 0 
2 6 0 - 
y = 1522 + 1 0 3 5 x - 2 5 0 - r = 56 
E 
240 
230 
0 
c 
cn" 2 2 0 
t" 2 0 0 - 
a 190- 
U 
210- - 
I 8 . O t / 
40 50 .60 .70 .80 .90 10 
Body Surface Area (meters2) 
FIG. 5 . Mean value (y) (mm) for the aortic dimension at end- 
systole and the 95% confidence interval plotted as a function of 
body surface area (BSA); y is determined from the regression equa- 
tion y = 15.22 + 10.35x, where x is the BSA. The correlation 
coefficient (r) is 0.56. 
VOL. 24, No. 5 ECHOCARDIOGRAPHY IN NORMAL DOGS 
25 
24 
23 
22 
21 
20 
19 
18 
17 
16 
217 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
E 
E - 
26.0 
25.0 
24.0 
23.0 
22.0 
21.0 
- 
E 
E 
4. 
J 18.0- 
- 
._ : 20.0 
+ 19.0- 
+ 
r 
u c 
W - 
- 
- 
- 
- 
- 
- 
- 
0 
0 
c L 
a 
/ 
y = 12 83 + 12 1 7 x 
r = .67 
1 1 I I I I I J 
.40 .50 60 .70 .80 90 1.0 
Body Surface Area (meters2) 
FIG. 6. Mean value (y) (mm) for the aortic dimension at end- 
diastole and the 95% confidence interval plotted as a function of 
body surface area (BSA); y is determined from the regression equa- 
tion y = 12.83 + 12.17x, where x is the BSA. The correlation 
coefficient (r) is 0.67. 
Correlations of mitral valve slopes and amplitude of 
motion, percent systolic thickening of the left ventric- 
ular posterior wall, and percent change in minor di- 
ameter of the left ventricle to heart rate were not sta- 
tistically significant. Correlation coefficient values 
ranged from 0.0 to 20.6%. 
Table 3 shows the comparison of mean raw data 
from this study with mean values previously reported 
in the Student’s t-tests showed a signifi- 
y = 12.63 + 12 .05~ 
r =.54 
/ 
/ 
l7.Ol’ 16.0 / 
50 - 
48 - 
y = 15.63 + 31.25 x - E - r =.74 E 46- 
c .o 44- 
2 42- .- a 
0 
L 
I I I I I 1 
,440 .50 60 .70 .80 .90 1.0 
Body Surface Area (meters2) 
FIG. 8. Mean value (y) (mm) for the left ventricular end-diastolic 
dimension and the 95% confidence interval plotted as a function of 
body surface area (BSA); y is determined from the regression equa- 
tion y = 15.63 + 31.25x, where x is the BSA. The correlation 
coefficient (r) is 0.74. 
I I I I I I 
.40 5 0 .60 .70 .80 .90 1.0 I I 1 I I I 
.40 .50 .60 .70 .80 .90 1.0 
Body Surface Area (meters‘) Body Surface Area (meters‘) 
FIG. 7. Mean value (y) (mm) for the left atrial end-systolic di- 
mension and the 95% confidence interval plotted as a function of 
body surface area (BSA); y is determined from the regression equa- 
tion y = 12.63 + 12.05x, where x is the BSA. The correlation 
coefficient (r) is 0.54. 
FIG. 9. Mean value (y) (mm) for the left ventricular end-systolic 
dimension and the 95% confidence interval plotted as a function of 
body surface area (BSA); y is determined from the regression equa- 
tion y = 9.0 + 21.18x, where x is the BSA. The correlation coef- 
ficient (r) is 0.72. 
BOON ET AL. 218 
- 
E 8.0- 
E - 
0) U 
c '= 7.0 
U 
5 6.0 
E 
a 
v) 
0 
L 
3 5.0 
._ 
I c 
C 
> 
4.0 
t 
C - 
3.0 
1983 
- 
- 
- 
- 
- 
I I I I I I 
.40 .50 .60 .70 .80 .90 1.0 
Body Surface Area (meters2) 
140- 
130- 
1 2 0 - 
110- 
100 
9 0 - 
0 0 - 
7 0 - 
FIG. 10. Mean values (y) (mm) for the left ventricular posterior 
wall at end-systole and end-diastole and their 95% confidence in- 
tervals plotted as a function of body surface area (BSA); y is de- 
termined from the regression equations y = 6.67 + 6 . 3 5 ~ and y = 
4.05 + 4.07x, respectively, where x is the BSA. The correlation 
coefficients (r) are 0.53 and 0.51, respectively. 
- 
- 
E I 5 O r / 
y = 332 + 9 9 0 x 
r = 49 
Body Surface Area (meters') 
FIG. 11. Mean value (y) (mm) for the left ventricular posterior 
wall amplitude of motion and the 95% confidence interval plotted 
as a function of body surface area (BSA); y is determined from the 
regression equation y = 3.32 + 9.90x, where x is the BSA. The 
correlation coefficient (r) is 0.49. 
16 
15 - 
14 
I3 - 
12 
l l - 
10 
9- 
8 - 
7 - 
6 - 
- 
- 
- 
- 
/ 
End Systollc Dlmenslon 
y = 7.92 + 8 . 4 6 ~ 
End Dloslollc Dlmenslon 
y * 4 .59 + 6 . 3 3 ~ 
r = .71 
I 1 I I I I 1 I 
40 50 60 70 80 .90 1.0 
Body Surface Area (meters') 
FIG. 12. Mean values (y) (mm) for the interventricular septa1 
thickness at end-systole and end-diastole and their 95% confidence 
intervals plotted as a function of body surface area (BSA); y is 
determined from the regression equations y = 7.92 + 8 .46~ and y 
= 4.59 + 6.33x, respectively, where x is the BSA. The correlation 
coefficients (r) are 0.68 and 0.71, respectively. 
cant difference at the p < .05 level between the values 
obtained in the present study and previously published 
data' for the interventricular septum and posterior wall 
dimensions. When the present values were compared 
9'0 i 
I I I I I I I 
.40 50 .60 .70 .80 .90 1.0 
Body Surface Area (meters') 
FIG. 13. Mean value (y) (mm) for the interventricular septum am- 
plitude of motion and the 95% confidence interval plotted as a func- 
tion of body surface area (BSA); y is determined from the regression 
equation y = 2.07 + 5.86x, where x is the BSA. The correlation 
coefficient (r) is 0.49. 
VOL. 24, No. 5 ECHOCARDIOGRAPHY IN NORMAL DOGS 219 
ographic measurement and 95% CI of a parameter can 
be determined for a specific BSA. For more accuracy 
than allowed by the figures, Table 1 should be used to 
interpolate CIS within or extrapolate CIS outside the 
rangeof BSAs used in this study. 
None of the indices of left ventricular function, mi- 
tral valve motion velocities, or dimension ratios 
showed significant correlation to BSA (Table 2). These 
values, therefore, apply to the echocardiogram of any 
dog, regardless of size. 
Student’s t-tests comparing the means of the present 
data with previously reported show a signif- 
icant difference for several parameters (Table 3). These 
differences may result from (1) variations in posi- 
tioning of animals or transducers; (2) variations in 
range of animal sizes; (3) excitability of the animal, 
--Ip I 
40 5 0 60 70 80 90 10 . 
Body Sur face Area (meters‘) 
FIG. 14. Mean value (y) (mm) for the mitral valve CE amplitude 
of motion and the 95% confidence interval plotted as a function of 
body surface area (BSA); y is determined from the regression equa- 
tion y = 13.05 + 10.66x, where x is the BSA. The correlation 
coefficient (r) is 0.61. 
with those of a second publication,2 only the mitral 
value EF slope showed no significant difference at the 
p < .05 level. 
Discussion 
The present study relates normal canine echocar- 
diographic dimensions to BSA. The need to relate di- 
mensions to BSA is apparent from the results, which 
show a linear relation between increasing body size 
and increasing heart size. This correlation existed for 
all cardiac chamber dimensions, wall thicknesses, and 
amplitudes of motion studies (Figs. 3-14, Table 1). 
From the figures an estimate of the mean echocardi- 
which can affect heart rate and, thus-, diastolic filling 
time and contraction; (4) differences in transducer fre- 
quency, which may affect resolution; (5) use of anes- 
thetic to quite the animal; or (6) different methods of 
measurement. 
Limitations 
These regression equations and CIS are useful and 
appear accurate in clinical usage at the authors’ hos- 
pital, but several factors need further investigation. 
There is greater assurance of accuracy when mean 
values and CIS are predicted at a BSA within the range 
of body sizes studied (0.49-0.74 m2) than outside this 
range. l6 It is assumed that extrapolation for larger and 
smaller BSAs is useful and accurate, but research is 
necessary to assess the applicability of these equations 
and CIS to the population excluded from the present 
study. 
TABLE 1. Determination of 95% CI for Echocardiographic Parameters Related to BSA in Normal Dogs 
Parameter* Regression Equation S 9 X O 
Ao-ESd 
Ao-EDd 
A Ao W-amp 
PAoW-amp 
MV-CE amp 
LA-ESd 
LV-EDd 
LV-ESd 
LVPW-ESd 
LVP W-amp 
IVS-EDd 
IVS-amp 
LVPW-EDd 
IVS-ESd 
9, = 15.22 + (10 .35)~~ 
9, = 12.83 + ( 1 2 . 1 7 ) ~ ~ 
9, = 2.51 + ( 7 . 2 2 ) ~ ~ 
9, = 2.92 3. ( 6 . 3 5 ) ~ ~ 
9, = 12.63 + (12.05)~~ 
9, = 13.05 + (10 .66)~~ 
9, = 15.63 + ( 3 1 . 2 5 ) ~ ~ 
9, = 9.00 + (21 .18)~~ 
9, = 6.67 + ( 6 . 3 5 ) ~ ~ 
9, = 4.05 + ( 4 . 0 8 ) ~ ~ 
9, = 3.32 + ( 9 . 9 0 ) ~ ~ 
9, = 7.92 + ( 8 . 4 6 ) ~ ~ 
9, = 4.59 + ( 6 . 3 3 ) ~ ~ 
9, = 2.07 + ( 5 . 8 6 ) ~ ~ 
d0.21 + 12.64 (x, - 0.73)’ 
d0.21 + 12.46 (x, - 0.72)’ 
d0.08 + 4.58 (x, - 0.73)’ 
d0.32 + 19.27 (x, - 0.73)’ 
d0.17 + 10.36 (x, - 0.73)’ 
d0.08 + 5.11 (x, - 0.72)’ 
V0.72 + 43.64 (x, - 0.73)’ 
V0.37 + 22.67 (x, - 0.73)* 
d0.10 + 5.79 (x, - 0.73)’ 
d0.04 + 2.61 (x, - 0.73)’ 
d0.34 + 6.09 (x, - 0.72)’ 
d0.16 + 2.80 (x, - 0.72)’ 
40.11 + 6.55 (x, - 0.73)’ 
d0.32 + 18.15 (x, - 0.73)’ 
* All measurements in mm. 
Ao = aorta; AAoW = anterior aortic wall; amp = amplitude of motion; BSA = body surface area (m2); CI = confidence interval; EDd 
= end-diastolic dimension; ESd = end-systolic dimension; IVS = interventricular septum; LA = left atrium; LV = left ventricle; LVPW 
= left ventricular posterior wall; MV = mitral valve; PAoW = posterior aortic wall; S9,, = variance of estimate (9,) about regression line; 
x, = BSA of dog parameter is evaluated for; 9, = estimate of mean dimension for given BSA. 
220 BOON ET AL. 1983 
TABLE 2. Echocardiographic Parameters with no Correlation to BSA in Normal Dogs 
X SD SEM 95% CI Range - Parameter* 
MV DE slope 
MV EF slope 
MV CD slope 
LAIAo 
% thickening IVS 
% thickening LVPW 
IVSILVPW 
% AD 
ET 
Vcf 
447 
106 
53 
0.95 
60.99 
61.73 
1.18 
36.26 
179 
2.07 
89.3 
32.9 
14.5 
1.57 
18.70 
14.00 
0.18 
5.67 
0.37 
18.0 
19.98 
7.36 
3.33 
0.04 
4.18 
3.13 
0.04 
1.27 
4.3 
0.09 
405-488 
91-121 
46-60 
0.88-1.02 
52.24-69.74 
55.19-68.26 
1.10-1.26 
33.60-38.92 
170-188 
1.89-2.26 
283-603 
54-175 
23-76 
0.65-1.36 
23.15-91.43 
34.44 - 88.89 
0.84-1.50 
26.9-48.3 
154-2 18 
1.58-2.79 
* Slopes measured in mmlsec; ejection time in msec; Vcf in cmlsec. 
Ao = aorta; BSA = body surface area; CI = confidence interval; % AD = % change in minor diameter; ET = ejection time; IVS = 
ventricular septum; LA = left atrium; LVPW = posterior wall left ventricle; MV = mitral valve; SD = standard deviation; SEM = 
standard error of the mean; X = mean; Vcf = velocity of circumferential fiber shortening. 
Correlation coefficients listed in Figures 3 -14 range 
from 0.49 to 0.74. That they were not higher probably 
reflects the limited number of dogs in the study as well 
as the many factors that can influence cardiac size and 
function, e . g . , sex, breed, age, nervous stimulation, 
and athletic tendencies. Studies to investigate the ef- 
fects of these variables on the canine echocardiogram 
are necessary. 
Applications 
Entire books and hundreds of journal articles can 
be cited for clinical application of the measurements 
of dimension, function, and motion studied. A few ap- 
plications are included in this discussion. 
Mitral and aortic regurgitation, cardiomyopathy, 
anemia, patent ductus arteriosus, and ventricular 
septal defect are among the causes of left ventricular 
volume overload. Volume overload dilates the ventric- 
ular chamber and, depending on the cause of overload, 
increases or decreases septal and posterior wall thick- 
nesses and amplitudes of motion. Septal motion usu- 
ally also changes with coronary artery disease, peri- 
carditis, and arrhythmias.17 
The same causes of volume overload usually also 
TABLE 3. Comparison of Mean Values Obtained in Present Study 
with Those Previously Reported for Dogs 
Student's 
Parameter Mashiro' Dennis2 Boon 2-test 
LV EDd 37.3 - 38.5 0.97 
LV ESd 25.8 - 24.5 1.51 
IVS EDd 6.4 - 8.2 5.45* 
LVPW EDd 6.3 - 7.0 3.04* 
MV EF slope - 94.6 106 1.55 
CE amplitude - 17.6 20.8 6.27r 
Ao EDd - 18.4 21.6 5.42* 
* Significant difference in the mean values with t tested at the 5% 
level, 19 degrees of freedom (t = 2.093) for all but Ao EDd, which 
had 16 degrees of freedom (t = 2.131). 
Ao = aorta; EDd = end-diastolic dimension; ESd = end-systolic 
dimension; IVS = ventricular septum; LV = left ventricle; LVPW 
= left ventricular posterior wall; MV = mitral valve. 
dilate the left atrium. The left atrial/aortic root ratio 
frequently indicates the degree of left atrial enlarge- 
ment. In humans this ratio is more accurate with di- 
lation due to mitral regurgitation and myocardial dis- 
ease than with enlargement resulting from aortic val- 
vular d i s e a ~ e . ' ~ 
Because mitral regurgitation can be associated with 
or caused by many cardiac disorders, e.g., cardio- 
myopathies, papillary muscle dysfunction, ruptured 
chordae, endocardiosis, and congenital defects, it is a 
challenge to diagnose and differentiate the problem. 
The diastolic opening velocity (DE slope), early dia- 
stolic closing velocity (EF slope), and amplitude of 
motion of the mitral valve are often used to evaluate 
and differentiate the various causes of mitral incom- 
petence. l 8 Velocity of circumferential fiber shortening 
and percent change in minor diameter are alsouseful 
in evaluating mitral insufficiency. These values are 
high or normal in the well compensated heart with 
mitral incompetence due to valvular lesions and below 
normal in the decompensated heart or in patients with 
mitral regurgitation secondary to myocardial dysfunc- 
tion.19 The presence or absence of hypertrophy and 
dilation is also important. In addition, mitral stenosis 
and effusions can affect the E F slope. Therefore, this 
slope is also sometimes useful as an indicator of left 
ventricular function. l3 
The indices of left ventricular function, which in- 
clude percent change in minor diameter, velocity of 
circumferential shortening, percent systolic thick- 
ening, and ejection time, are indicators of ventricular 
compliance and contractility. Ventricular function is 
not only affected directly with such diseases as coro- 
nary artery disease, valvular regurgitation, and car- 
diomyopathy but also can be altered indirectly by such 
conditions as effusions or anemias.13 
In addition, echocardiography can help in the eval- 
uation of hypertrophic patterns. Septal and posterior 
wall thicknesses and the septal wall posterior wall ratio 
can often indicate the degree of thickening and differ- 
VOL. 24, No. 5 ECHOCARDIOGRAPHY IN NORMAL DOGS 22 1 
entiate between symmetric and asymmetric hyper- 
trophy. l4 
None of these parameters alone should be used to 
assess a disorder; rather, each one contributes infor- 
mation concerning cardiac structure and function. 
Knowledge of normal measurements for a specific 
BSA can help to indicate the degree and direction of 
change from normal, which will make the echocardi- 
ogram easier to interpret. 
Summary 
The regression lines and 95% CIS presented allow 
the evaluation of canine echocardiographic parameters 
with increased accuracy. Measurements can fall 
within, above, or below the normal range expected for 
a parameter at a given BSA. This information can then 
help the clinician to assess the clinical status or pro- 
gression of a cardiac disorder. 
REFERENCES 
1. Dennis MO, Nealeigh RC, Pyle RL, et al. Echocardiographic 
assessment of normal and abnormal valvular fmction in beagle 
dogs. Am J Vet Res 1978;39:1591-8. 
2. Mashiro I, Nelson RR, Cohn JN, Franciosa JA. Ventricular 
dimensions measured noninvasively by echocardiography in the 
awake dog. J Appl Physiol 1976;41:953-9. 
3. Baylen BG, Garner DJ, Laks MM, Yoshida Y, Emmanouil- 
ides GC. Improved echocardiographic evaluation of the closed- 
chest canine: methods and anatomical observations. J Clin Ult 
1980;8:335-40. 
4. Pipers FS, Andrysco RM, Hamlin RL. A totally noninvasive 
method for obtaining systolic time intervals in the dog. Am J Vet 
Res 1978;39:1822-6. 
5. Pipers FS, Bonagura JD, Hamlin RL, Kittleson M. Echocar- 
diographic abnormalities of the mitral valve associated with left- 
sided heart disease in the dog. J Am Vet Met Assoc 1981;179: 
580-6. 
6. Bonagura JD, Pipers FS. Echocardiographic features of peri- 
cardial effusion in dogs. J Am Vet Med Assoc 1981;179:49-56. 
7. Roge CL, Silverman NH, Hart PA, Ray RM. Cardiac struc- 
ture and growth pattern determined by echocardiography. Circ 
1978;57:285-90. 
8. Henry WL, Ware J, Gardin JM, et al. Echocardiographic 
measurements in normal subjects. Circulation 1978;57:278-90. 
9. Gardin JM, Henry WL, Savage DD, et al. Echocardiographic 
measurements in normal subjects: evaluation of an adult population 
without clinically apparent heart disease. J Clin Ult 1979;7:439-47. 
10. Madewell BR, Theilen GH. Veterinary cancer therapy. Phil- 
adelphia: Lea & Febiger, 1979. 
11. Sahn DJ, DeMaria A, Kissio J, Weyman A. Recommenda- 
tions regarding quantitation in M-mode echocardiography: results 
of a survey of echocardiographic measurements. Circulation 
12. Belenkie I, Nutter DO, Clark DW, McCraw DB, Raizner AE. 
Assessment of left ventricular dimensions and function by echocar- 
diography. Am J Cardiol 1973;31:755-62. 
13. Parisi AF, Moynihan PF, Folland ED. Echocardiographic 
evaluation of left ventricular function. Med Clin North Am 
1980;64: 6 1- 8 1. 
14. Kansal S, Roitman D, Sheffield LT. Interventricular septal 
thickness and left ventricular hypertrophy. Circulation 
15. Brown OR, Harrison DC, Popp RL. An improved method for 
echographic detection of left atrial enlargement. Circulation 
16. Huntsberger D, Billingsley P. Elements of statistical infer- 
ence. 5th ed. Boston: Allyn and Bacon, 1981. 
17. Tajik AJ, Seward JB, Giuliani ER. Ventricular septal motion: 
clinical and echocardiographic correlations. Cardiovasc Clin 
18. Burgess J, Clark R, Kamigaki M, Cohn K. Echocardiographic 
findings in different types of mitral regurgitation. Circulation 
19. Rosenblatt A, Clark R, Burgess J , Cohn K. Echocardio- 
graphic assessment of the level of cardiac compensation in valvular 
heart disease. Circulation 1976;54:509-18. 
1978;58: 1072-83. 
1979;60: 1058-65. 
1974 ;50:58-64. 
1973 ;5:209-28. 
1973 ;48 :97-106. 
APPENDIX 
Application of Equations in Table 1 
The left ventricular posterior wall end-diastolic dimension 
and 95% CI in a dog with a BSA of 0.40 m2 would be de- 
termined in the following manner from Table 1: 
2. Determine Sg,, by again inserting 0.40 m2 for x,: 
Sg,, = V0.04 + 2.61 (0.40 - 0.73)’ 
sg,, = 0.57 
1. Determine 9, from the regression equation by inserting 3. Calculate the CI using the equation given for a 95% 
probability level. Insert 9, derived in step 1 and Sg,, derived 
in step 2: 
0.40 m2 for x,: 
90 * (t0.025) (SYxo) 
9, = 4.05 + (4.08) (.40) 5.68 2 (2.101) ( S 7 ) 
go = 5.68 4.48 S 9, 6.88 
INSTRUCTIONS TO AUTHORS 
APPEAR IN THE JULY/AUGUST 1983 
ISSUE OF VETERINARY RADIOLOGY