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Right ventricular volume in congenital heart disease
PEDIATRIC CARDIOLOGY
Right Ventricular Volume in Congenital Heart Disease
ELIZABETH
A.
FISHER,
MD
IRA W. DuBROW, MD ALOIS R. HASTREITER, MD, FACC Chicago, Illinois
From the Division of Pedllric Cardiology, University of Illinois Hospital and Abraham Lincoln School of Medicine, Chicago, Ill. This study was supported in part by The University of Illinois Foundation Goodenberger Medical Research Grant 2-44-33-66-3-14. Manuscript accepted November 26, 1974. Address for reprints: Elizabeth A. Fisher, MD, Department of Pediatrics, University of Illinois Hospital, 840 South Wood St., Chicago, III. 60612.
Methods for angiographic determination of right ventricular volume were compared in right ventricular cast studies and in vivo using a semiautomated Simpson’s rule, elliptical and rectangular cross sections and a simple geometric model, a prism with a triangular base. In cast studies excellent correlation coefficients were obtained for all three methods (I = 0.97 to 0.98). In vivo, excellent linear correlation was obtained when the methods were compared (r = 0.98 to 0.99, P
Simpson’s rule has been shown to be an accurate method for angiographic determination of right ventricular volume.1,2 This method has had limited clinical use and right ventricular volume data are scanty because of the time-consuming and tedious measurements and calculations required when the technique is performed manually. The purpose of this paper is threefold: (1) to describe a semiautomated system for right ventricular volume determination by Simpson’s rule; (2) to compare this system with a simple geometric model used as a basis for simplified manual right ventricular volume determination; and (3) to present right ventricular volume data in a large group of infants and children, with both normal and abnormal right ventricles. Methods Ventricular Volume Determinations Right ventricular casts: Radiopaque plastic casts of dog, monkey, baboon and lamb hearts were made, utilizing Batson’s no. 17 Anatomical Corrosion Compound (Polysciences, Inc., Rydal, Pa.). Forty-eight casts with right
July 1975
The American Journal of CARDIOLOGY
Volume 36
67
RIGHT VENTfWLfLAR
VOLUME IN CHILDREN-FISHER
ET AL.
ventricles ranging in volume from 0.36 to 95.48 cc were prepared. The hearts were pressure-fixed3 and injected with the partially polymerized liquid mixed with barium sulfate paste to make it radiopaque. After the casts hardened the heart tissue was dissected free, the residual tissue was digested with concentrated potassium hydroxide solution, and the respective chamber casts were cut apart. True volumes were determined by water displacement. Radiographic volumes were determined from biplane frontal and lateral radiographs of the casts placed in anatomic position. The films were projected and the cast outlines traced by hand on paper. Plastic grids with 1 by 1 cm lead lines were radiographed at the center of each cast in both projections for purposes of correction for X-ray magnification. Simpson’s rule: Volumes were calculated by Simpson’s rule, assuming the cross-sectional areas to be either elliptical or rectangular. Manually, the drawings of the frontal and lateral projections were divided into 10 equally spaced sections by 11 horizontal lines. The volume of each section was ?r - X/2 - Y/2 . h for the elliptical cross section (where X is the frontal diameter and Y is the lateral diameter of the ellipse and h is the height of the section). For the rectangular cross section, the volume of each section was X . Y - h (where X is the frontal length and Y the lateral length of the rectangle and h is the height of the section). The sections were then summed to give the volume of the solid, as
Th 7j-
2L, where Af is the area of the frontal projection, A1 is the area of the lateral projection and L is the average of the frontal and lateral lengths. Frontal length was measured as the length of a perpendicular drawn between two parallel lines that intersected the top and bottom of the frontal projection. Lateral length was measured from the top of the pulmonary valve to the apex of the lateral projection (Fig. 1B). Areas were determined by planimetry. For each method, calculated volumes were plotted against true volumes and a linear regression analysis was made. In vivo volume determinations: Right and left ventricular volumes were determined from biplane cineangiocardiograms performed as a part of routine diagnostic cardiac catheterization studies. All patients were studied in the postabsorptive state. Only patients older than age 6 months were sedated with use of meperidine (Demerolm), promethazine (Phenerganm) and methazine (Sparinem) in intramuscular doses of 0.5 to 1 mg/kg, 0.25 to 0.5 mg/kg and 0.25 to 0.5 mg/kg, respectively. For patients older than age 2 years, additional sedation with droperidol-fentanyl (Innova@), 0.025 cc/kg up to 1 cc intravenously, was given if required. Biplane cineangiocardiograms were filmed at 64 or 80 frames/set after the high speed injection of 1 to 2 cc/kg of contrast medium (Conray 400@) into the inferior vena cava or right atrium. Cycles with premature contractions were not used. The earliest cardiac cycle with sufficient contrast to allow accurate tracing of chamber outlines was utilized, and in most cases right and left heart volumes could be determined from the same injection. Correction was made for X-ray magnification by a grid system as described earlier. Comparison of right and left ventricular volumes: Left ventricular volumes were determined by the standard Dodge biplane method,4 assuming the left ventricle to be an ellipse of revolution. The volume was calculated as 4rl 3.L1/2.L2/%L3/2, where L1 = the longer of two lines drawn from the center of the aortic valve to the apex in the frontal and in the lateral projections, Lp = the short axis of the frontal projection and L3 = the short axis of the lateral projection. L1 was measured directly; Lz and L3 were calculated by the formulas: L2 = 4Af/7rLl and Ls = 4Al/~L1, where Af and A1 are the areas of the frontal and lateral projections of the ventricle, respectively. Volumes were corrected by a regression equation determined from left ventricular cast studies: V’ - 0.85V, where V’ = corrected volume and V = calculated volume. As a test of the methods, angiographic stroke volumes of the right and left ventricles were compared in 91 infants and children with no shunts or valvular insufficiency. Right and left ventricular volumes and ejection fractions were also compared in two groups of patients believed to have normal right or left heart chambers (70 and 77 patients, respectively). Comparison of methods: Angiographic right ventricular volumes were determined by Simpson’s rule (semiautomated method), elliptical and rectangular cross sections and the prism method in 218 infants and children and the results compared after correction with the appropriate regression equations obtained from the cast studies.
1
[
;i’X,,Y,, + X,,,Y,,,)-t end segments (X,Y,
+
X,;Y ( +
odd-numbered
;(x?E’,
.
+
X,Y,J
+
X,Y,
+
even-numbered for the elliptical
+
cross-section
X,,,Y,,J
-t
segments
+
X,Y,)
1
segments
and
-t
end segments
(X,Y, + X,;Y,, + odd-numbered $XjY,
+ X,,Y,,) t
segments +
X,Y,
even-numbered
+
+ segments
X,\Y,,
1
for the rectangular cross section. By the semiautomated method, the drawings were traced with an electronic planimeter (Numonics Corporation, electronic graphics calculator) linked to a programming calculator (Wang 7OOC series) and plotting output writer (Wang 702 series). Using the X, Y coordinates the calculator was programmed to automatically divide the drawings by horizontal lines spaced at 5 mm intervals and to calculate the volumes by the formulas given above. Prism method: By inspection of the casts it was considered that a prism with a triangular base was the simpk geometric solid that most closely corresponded to the shape of the right ventricular casts. The frontal and lateral projections were assumed to be rectangular and to form the sides of a triangle in the horizontal plane. The model and derivation of the formula for its volume are shown in Figure 1A. Simplified, the formula is Af - Al/
68
July 1975
The American
Journal of CARDIOLOGY
Volume
Case
Material
Normal right ventricular volumes: Right ventricular volume was determined in 70 infants and children believed t,o have a normal right heart chamber. All patients in this group had a peak systolic pressure of less than 35 mm Hg and an end-diastolic pressure of less than 5 mm Hg in the
36
RlGHT VENT’RKXAR VDLLM
IN CMDREN-FISISR
ET AL.
FIGURE 1. Right ventricular model (A) and projections (B). Correspond-
ing measurements are indicated. 0 = average width in frontal plane; L = average length; W = average width in lateral plane. right ventricle. The group contained 31 patients with normal hemodynamic status studied because of arrhythmias, pulmonary disease, mediastinal masses, abnormal electrocardiograms or atypical murmurs. Nine patients had a small patent ductus arteriosus and five had undergone surgical closure of a patent ductus. Four patients had mild pulmonary stenosis (peak systolic gradient less than 15 mm Hg), 10 had mild to moderate aortic stenosis and 2 had undergone surgery for aortic stenosis. Five patients had mild to moderate mitral insufficiency, one mitral stenosis, one mild aortic insufficiency and two systemic hypertension. Their ages ranged from 0.5 to 21.75 years and body surface areas from 0.35 to 1.83 m2. Abnormal right ventricular volumes: Five groups of patients with an abnormal right ventricle were studied and the results compared with normal findings. Group 1 consisted of 44 patients with pulmonary stenosis. Ten of these had undergone surgery at least 1 year previously and had a residual peak systolic gradient from the pulmonary artery to the right ventricle of less than 20 mm Hg and a right ventricular peak systolic pressure less than 40 percent of systemic peak systolic pressure. Only one patient had radiographic cardiac enlargement postoperatively, and he had significant pulmonary insufficiency. The ages of the patients studied postoperatively ranged from 1.75 to 16.5 years and body surface areas from 0.51 to 1.73 ml. Of the 34 patients studied preoperatively, 20 had a pressure gradient of less than 50 mm Hg; the remainder (14 patients) had a gradient of 50 mm Hg or more. In 8 patients of this group peak right ventricular pressure was less than 40 percent of systemic, in 11 it was 40 to 60 percent, in 7 it was 60 to 100 percent and in 8 it was 100 percent of systemic pressure or greater. The ages of the patients studied preoperatively ranged from 0.75 to 23.0 years and body surface areas from 0.36 to 1.72 m2. Group 2 contained 21 patients with a left to right shunt at the atrial level. Eleven of these were studied preoperatively, nine with a secundum atria1 septal defect, one with a
primum atria1 septal defect and one with total anomalous pulmonary venous drainage. Their ages ranged from 0.83 to 16.67 years and body surface areas from 0.31 to 1.60 m*. Ten patients of this group were studied postoperatively, two who had undergone correction of total anomalous pulmonary venous drainage, one with repair of a secundum atria1 septal defect and seven with repair of a primum atrial septal defect. They were studied 0.17 to 5.0 years postoperatively, with seven studied 1 to 2 years postoperatively. Their ages ranged from 0.17 to 16.33 years and body surface areas from 0.34 to 1.70 mP. None had significant radiographic cardiac enlargement or residual lesions postoperatively. Group 3 contained 49 patients with a ventricular septal defect. Sixteen had a moderate to large subaortic defect with a pulmonary to systemic blood flow ratio greater than 1.5: 1. Fifteen had a small shunt with a pulmonary to systemic flow ratio less than 15: 1; two in this group had had a previous pulmonary arterial banding. The ages of these 31 patients ranged from 0.04 to 23.42 years and body surface areas from 0.20 to 1.87 mp. The remaining 18 patients in this group had undergone operation at least 1 year previously. Their ages ranged from 0.45 to 16.33 years and body surface areas from 0.45 to 1.60 m*. Only one had a large residual defect. Group 4 contained 22 patients with tetralogy of Fallot, II studied preoperatively and 11 studied at least 1 year after operation. In the patients studied postoperatively, ages ranged from 4.67 to 17.42 years and body surface areas from 0.75 to 1.89 m2. Two had significant pulmonary insufficiency, one manifesting radiographic cardiac enlargement. One postoperative patient had a residual ventricular septal defect with small left to right shunt, and one had significant residual pulmonary stenosis. In the patients studied preoperatively ages ranged from 0.17 to 5.33 years and body surface areas from 0.26 to 0.77 m2. Although one patient had significant pulmonary insufficiency, his heart size was radiographically normal.
July 1975
The Amerkan
Journal 01 CARDIOLOGY
Volwne 36
69
RKZHTVENTRKYJLAR VOLUME IN CHILDREN-FISHER ET AL.
TABLE
Regression
Analysis of Right Ventricular
Cast Studies
r Method
value
Simpson’s ellipse, manual Simpson’srectangle, manual Simpson’s ellipse, auto Simpson’s rectangle, auto Prism auto
calculation of small volumes. For the respective cross-sectional models (ellipse or rectangle), the regression equations for Simpson’s rule were quite similar using either the manual or semiautomated method. In vivo volume determinations-comparison of right and left ventricular volumes: There was a very high correlation between left and right ventricular stroke volumes in patients with no shunts or valvular insufficiency (r = 0.94, P. When normal volumes were ex-
I
=
semiautomated
the estimate;
V = calculated
Regression Equation
SEE
0.97 0.97 0.97 0.97 0.98
5.79 5.79 3.77 3.76 2.94
method;
V’ V’ V’ V’ V’
SEE =
volume;
= = = = =
0.77v 0.6OV 0.71v 0.56V 1.16V
standard
V’ = corrected
- 2.92 - 2.99 - 1.15 - 1.15 - 1.04
error of volume.
Group 5 contained 12 patients believed to have myocardial disease. Ten had endocardial fibroelastosis, three with an associated tiny ventricular septal defect. Two had a primary cardiomyopathy (one due to Pompe’s disease and one of unknown origin). All had an abnormal electrocardiogram. Nine manifested left ventricular enlargement, one right ventricular enlargement, one combined ventricular enlargement and one Wolff-Parkinson-White syndrome, type B. Eight had radiographic cardiac enlargement, and six had hepatomegaly at the time of study. Eight had a history of congestive heart failure, but only three had failure at the time of study. Eight patients were receiving digoxin. At cardiac catheterization all standard hemodynamic measurements were normal in seven patients; four had elevated left ventricular end-diastolic pressure, one had elevated right ventricular end-diastolic pressure and one had elevated right and left ventricular end-diastolic pressures. Cardiac output, measured by the Fick method in only four patients, was normal. These patients’ ages ranged from 0.08 to 14.98 years and body surface areas from 0.2 to 1.54 m2.
Results Right ventricular casts: Regression analysis comparing true and calculated cast volumes (Table I) yielded high correlation coefficients for all methods. Standard errors were low for all methods and lowest (2.94) for the prism method. The Y intercepts for all methods were about 1 cc, making them applicable to
TABLE
II
Comparison
of Right and Left Ventricular
Volumes (ml) _---
Chamber
Reference
Age Group
Present
study
RV LV
Children Children
Graham Graham
et al.’ et aLy
RV LV
<1 yr/>l <2 yr/>2
Thilenius and ArcilIac
RV LV
<13 mo/>13 <13 mo/>13
Gentzler et al.’ Kennedy et al.:
RV LV
Adult Adult
EL&‘/m’
yr yr mo mo
ESV/m2
July 1975
The American Journal of CARDIOLOGY
25 19
39 40
0.61 0.68
39/70 42173
13125 13/27
26/45 29/46
0.66/0.64 0.68/0.63
64/78 43166
31/30 10/17
33148 34/48
0.52/0.61 0.79/0.74
39 24
42 45
0.51 0.67
81 70
Volume 36
EF
64 59
EDV/m’ = end-diastolic volume per square meter of body surface area; EF = ejection fraction; square meter of body surface area; LV = left ventricle; RV = right ventricle; SI = stroke index.
70
SI
ESV/m” = end-systolic
volume
per
RIGHT VENTRICULAR VOLUME H CfifLDREN-FISHER ET AL.
A
RVEDV, SIMPSON'S RULE vs PRISM METHOD NORMALS -
RVED",SIWSON'SICXLE "S PRISMMETHOD ABNOPnAL\
6
Y=I.OX-3.1 r-.98 N=149 sEt=6,8
+
++ + + + + +
+
+
+
SIMPSON'S 100: EDV(m1)
+ +++ /
‘/
;z__L____l____l____I____1____~____~____~____1
+____l____r____l____I--__r--_~___l_--_~
25
50
7s
100 125 PRISM EDV(ml)
+
150
175
.'5
200
50
li)O I.'5 1'10 Iii PRlSMll""("!l)
7'1
225
200
FIGURE 2. Comparison of right ventricular volumes calculated using Simpson’s rule, elliptical cross section, and the prism method in subjects with normal (A) and abnormal (6) conditions. EDV = end-diastolic volume; N = number of cases: RVEDV = right ventricular end-diastolic volume; SEE = standard error of the estimate; X = volume calculated by prism method: Y = volume calculated by Simpson’s rule.
pressed per square meter of body surface area, there remained a small but significant correlation with age (r = 0.40, P CO.01). Normal values for end-systolic volume/m2, stroke index and ejection fraction are given in Table III. Abnormal right ventricular volumes: The data are summarized in Table III and shown graphically in Figures 3 to 7. In Group 1 (pulmonary stenosis) values for mean end-diastolic volume/m2, end-systolic volume/m2 and stroke index were below normal (P
RVEDV s
BSA, PULMONARY STENOSIS
ZOO? , 175; , 1 150:' , ' 125:
/ /
RV/LV Pressure (%) x = less than 40 0 = 40-60 - = 60-100 .- 100 or more --_--_---_--_---_ * = postoperative
/
I
1
2
BSA(m')
FIGURE 3. Patients with pulmonary stenosis. Variation of right ventricular end-diastolic volume (RVEDV) with body surface area (BSA). Normal mean and 90 percent confidence limits are indicated by the solid and dashed lines, respectively. LV = left ventricular; RV = right ventricular.
umes and ejection fraction were normal. The one patient with an end-diastolic volume more than 2 standard deviations above the normal mean value had pulmonary insufficiency and radiographic cardiac enlargement. In Group 2 (atria1 left to right shunt) mean volumes were considerably above normal (end-diastolic volume/m2, P
July 1975
The American Journal of CARDIOLOGY
Volume 36
71
61 + 31 65 f 23 NS
77 3: 40 79 = 38 NS
S P D
S P D
S P D
S P D
11
31
11
12
ASD
VSD
ToF
MY0
I:
37 2. 27 39 7 27 NS
. .
NS NS .
NS NS .
NS NS
~0.050 .::0.025
~‘0.025 *-0.050 ..
P
39 I 17 38 i 19 NS
38 = 21 42 3. 16 NS
37 L 13 39 .+. 12 NS
62 I:. 24 65 .! 20 NS
34 i 11 34 .! 10 NS
39 :r 11 39 -: 10 NS
Mean :lSD
.
P
0.60 .r 0.07 0.60 -:. 0.06 NS 0.62 7 0.11 0.65 + 0.10 NS 0.56 + 0.13 0.51 I 0.15 NS
NS NS . . NS NS NS NS . .
P
NS <0.005
.
NS NS
NS NS
NS NS
GO.005 CO.010 .
-.
... ...
... ...
11 70 + 17 71 + 17 NS
18 66 r 15 67 +: 14 NS
..
NS NS
. .
NS NS
.
31 i 14 31 3. 13 NS
28 L 9 30 ,c 12 NS
NS NS
NS NS .
NS ~0.050
NS NS
P
ToF = Tetralogy
.
Mean 1-k SD
EF
0.11 0.10
...
NS NS
NS <0.05
NS NS
NS NS
...
P
...
-I
VSD = ventricula
NS = not significant;
0.57 * 0.57 * NS
0.57 + 0.07 0.56 z 0.10 NS
0.65 -:: 0.08 0.63 z 0.05 NS
0.61 T 0.09 0.61 z 0.07 NS
of Falfot:
N = normal;
40 t 10 40 1 10 NS
37 -7 9 37 I. 9 NS
46 .L 11 48 : 11 NS
37 :L 13 40 T 13 -.:0.050
1-L SD
Mean
SI (ml)
Postoperative
disease;
NS NS ...
NS NS ...
NS NS ...
25 - 7 28 f 7 NS
10 71 .r 14 75 T 16 NS
NS NS
24 + 10 NS 26 i. 10 NS NS .
10 61 i. 20 NS 66 + 20 NS co.025
.
P
...
... ... ...
Mean 1 :I- SD
-. ESV/rn? (ml)
.
... ... ...
no.
EDV/m? (ml) _. Mean .: 1 SD P -
Myo = myocardial rule and by prism method; S = Simpson’s rule; SD = Standard deviation;
0.56 .!- 0.11 0.57 Y- 0.08 NS
0.67 -‘. 0.09 0.65 T 0.09 .:.0.050
0.61 T 0.08 0.61 + 0.07 NS
Mean -2. 1 SD
EF
.
~0.025 ~‘0.050
SI (ml)
ASD = atrial left to right shunt; D = difference between volumes by Simpson’s P = prism; P = significance of difference from normal; PS = pulmonary stenosis; septal defect.
NS NS ...
NS 221 13 23 t 10 NS
NS NS ...
8
24 26’
NS NS .
i 8
46 12 48 .: 13 NS
..
17 ‘. 7 18 .r 7 ‘TO.010
25.j 8 25 -L- 7 NS
: 1SD
Mean
ESVjm? (ml)
...
. ..
__~_
_---
61 -t 19 65 = 18 <0.025
109 I: 28 114 L 27 NS
50s 15 53 7 14 CO.050
S P D
34
PS
64 i 15 64 + 15 NS
Mean 4 1 SD
70
S P D
no. Method
N
Group
EDV/m’ (ml)
Preoperatrve
P
1
1 -n
k 2
Right Ventricular -
Volumes
3
III
TABLE
RtCHT VENTROJLAR VOLUME H CHILDREN-FISHER ET AL.
Group 3 (ventricular septal defect) had normal mean volumes with no difference found between patients with a large or small shunt or those studied before or after operation. The two patients with pulmonary arterial banding had low normal volumes. In Group 4 (tetralogy of Fallot) the mean volumes both pre- and postoperatively were normal. One patient studied preoperatively had an end-diastolic volume more than 2 standard deviations above the normal mean value (124 ml/m2). He did not have radiographic cardiac enlargement, but his right ventricular end-diastolic pressure was elevated for age (8.6 mm
Hg). A second patient studied preoperatively had high normal end-diastolic volume (94 ml/m2). He had moderate pulmonary insufficiency, but his end-diastolic pressure and radiographic heart size were normal. The one patient studied postoperatively with an end-diastolic volume/m2 slightly above 2 standard deviations from the normal mean value (95 ml) had significant pulmonary insufficiency. Ejection fraction was decreased in this patient (0.36) and in one other patient studied postoperatively (0.41). In neither one was heart size increased radiographically. Two other patients studied postoperatively had an end-diastolic
RVDV
NED" ys BSA, ATRIAL SEPTAL DEFECT
/ 9
BSA,
VENTRICULAR
SEPTAL
DEFECT
1 I t
0
2,o; 1754
vs
230;
225;
o=preoperative *=postoperative
175f
/
R
1 1
/ 150;
/
x=small +=pulmonary
artery
band
*=postoperative
1 RSA
fn?)
2
1
FIGURE 4. Patients with an atrial septal defect (atrial left to right shunt). Variation of right ventricular end-diastolic volume with body surface area. Conventions as in Figure 3.
I
./
o=large
RSAlm2) __~_\_.. ,
FIGURE 5. Patients with a ventricular septal defect. Variation of right ventricular end-diastolic volume with body surface area. Conventions as in Figure 3. RVEDV y> BSA, MYOCARDIALDISEASE 251Ji
KVEDV vs BSA, TETRALOGY OF FALLOT 200;
1751
o=preoperative
207:
*=postoperative
150;
/
/
/
,‘____P_‘I____L______r___________________L 1
.?
1 BSA(m2)
BSA(m2)
FIGURE 6. Patients with tetralogy of Fallot. Variation of right ventricular end-diastolic volume with body surface area. Conventions as in Figure 3.
2
FIGURE 7. Patients with myocardial disease. Variation of right ventricular end-diastolic volume with body surface area. Conventions as in Figure 3.
July 1975
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Volume 36
73
RIGHT VENTRICULAR VOLUME IN CHILDREN-FISHER
ET AL.
volume at the upper limits of normal (94 and 91 ml/ m2, respectively). Both had moderate pulmonary insufficiency, and one had cardiac enlargement by X-ray examination. In Group 5 (myocardial disease) mean end-diastolic volume/m2, mean end-systolic volume/m2 and mean ejection fraction were normal. Only two patients in this group had an end-diastolic volume more than 2 standard deviations above the normal mean value (135 and 161 ml/m2, respectively). Right ventricular stroke volume was increased in the former, patient (65 ml/m2). That patient had a normal ejection fraction (0.52), but ejection fraction was decreased (0.34) in the other. Corresponding left ventricular values for these patients were: end-diastolic volume/m2 203 and 219 ml, stroke index 76 and 57 ml, ejection fraction 0.37 and 0.36 and end-diastolic pressure 26 and 10 mm Hg. Cardiac output (Fick method) was 4.9 liters/min per m2 in the second patient, and 2.9 liters/min per m2 (with use of an assumed oxygen consumption) in the first patient. The second patient had elevated right ventricular enddiastolic pressure (10 mm Hg). Both had clinical evidence of right-sided heart failure with hepatomegaly. The first patient had massive mitral insufficiency believed to be secondary to cardiac dilatation. Discussion
The use of an electronic planimeter linked to a programming calculator and output writer greatly facilitates the application of Simpson’s rule to right ventricular volume determination. It is comparable in accuracy to the manual method, but the equipment is expensive and is not available in most laboratories. Therefore, Simpson’s rule remains limited in its clinical usefulness. The prism method requires no such equipment, the measurements are easily made manually and the calculations are quite simple. Objections to the use of a geometric model have been raised on the basis that it is less accurate than Simpson’s rule. However, in a previous report2 comparing Simpson’s rule with a geometric model in right ventricular case studies, little difference was shown in r values between the methods. No in vivo volume data were presented. Arcilla et al.” and Thilenius and Arcillas used a geometric model but did not compare results with Simpson’s rule. Graham et al.’ compared Simpson’s rule with two geometric models, finding little difference in the cast studies; they did not present a comparison of in vivo volumes by the various methods. Our investigation indicates that a simple geometric model, a prism with a triangular base, can be compared in accuracy with Simpson’s rule both in cast studies and in in vivo volume calculations. Normal Ventricular
Volumes
In comparing our right and left heart volumes we found the right ventricle to be slightly larger and to have a lower ejection fraction than the left. Other studies, one in infants and children” and another in adults,2,ga have found the same relation between the
74
July 1975
The American Journalof CARDIOLOGY Volume 36
right and left ventricles, but Graham et al.‘ps did not demonstrate any such differences in their studies (Table II). Although further data are needed to clarify this issue, it appears that the right ventricle is slightly larger than the left. Our normal data are comparable with those of previous reports, ls6 but we failed to demonstrate significantly lower volumes in infants. However, our youngest “normal” patient was 6 months old and only 7 of the 70 patients were less than 1 year of age, whereas in Graham’s study 6 patients were 5 months of age or younger and 7 of 16 in the normal group were less than 1 year of age. After normalization of volumes for body surface area, there remained a significant positive correlation with age. This observation is in agreement with other investigators’ findings of smaller volumes in young infants. Also, in this regard, Gentzler et a1.2 reported in adults with normal right heart chambers higher values than those reported by other&T6 in children. Abnormal
Right Ventricular
Volumes
Pulmonary stenosis: In contrast to Graham et al.,’ we found a small but definite decrease in mean right ventricular volume and stroke index, plus increased ejection fraction, in patients with pulmonary stenosis. Similar changes have been reported in left ventricular volume and ejection fraction in pediatric patients with aortic stenosis.” The right ventricle, as well as the left, is capable of ejecting an increased fraction of its volume of blood when exposed to a chronic increase in afterload. Whether this is due to increased contractility or to muscular hypertrophy remains to be investigated. The finding of normal mean volumes and ejection fraction in postoperative patients in this group lends support to the presence of a reversible adaptation to increased afterload in these patients. The individual patient in the postoperative group with increased volume had increased preload; thus, his condition was analogous to that of patients in Group 2 (atria1 left to right shunt). Gentzler et a1.2 described only two adult patients with pulmonary stenosis, both of whom had low values for end-diastolic volume (more than 2 standard deviations below the normal mean value in one). Both had a normal ejection fraction. Whether or not long-term pressure load of the right ventricle leads to compromise of function remains to be studied. Atria1 septal defect: Demonstration of’ a large increase in right ventricular volume in atria1 left to right shunt is in agreement with findings by Graham et al.’ in atria1 septal defect and total anomalous pulmonary venous drainage and by Gentzler et al.” in patients with tricuspid insufficiency and atria1 septal defect. Decreased ejection fraction in the patients in the latter study may have been due to long-term volume overload (increased preload) or to coronary artery disease or myocardial disease of other causes. In the absence of other such factors the right ventricle adapts to increased preload by increased end-diastolic and end-systolic volumes as well as increased
RM
stroke index, probably through the Starling mechanism. The finding of normal or nearly normal volumes postoperatively is evidence for a reversible adaptation to increased preload in children. Ventricular septal defect: No data are available on in vivo right ventricular volume in ventricular septal defect in children. Gentzler et a1.2 reported findings in two adult patients with a ventricular septal defect, one of whom also had right ventricular hypertension. Right ventricular volume was increased in the latter patient and normal in the other. In our group of 34 patients ventricular septal defect did not in most cases result in volume overload of the right ventricle. It may be that the site of the defect (in our study group all moderate to large defects were subaortic) results in shunting directly from the left ventricle to the pulmonary artery without overloading the right ventricle. Patients with a large muscular ventricular septal defect might then be expected to have an enlarged right ventricle. Tetralogy of Fallot: Patients with tetralogy of Fallot generally have normal heart size by X-ray examination, and this correlates well with our finding of normal mean right ventricular volume in this group. The lesion is a complex one and may, in the evolution of the disease, present predominantly a volume or a pressure load to the right ventricle. In general, the latter predominates and the right ventricle responds by hypertrophy but not enlargement. In the group of patients studied, right ventricular volume tended to be high normal or increased in the presence of pulmonary insufficiency, a situation resulting in increased preload.
VENTfMXJLAR VOLUME IN CHILDREN-FISHER
ET AL.
Myocardial disease: Our finding of normal mean right ventricular volume in patients with myocardial disease is in accord with similar findings by Gentzler et a1.2 in 7 of 13 patients with myocardial compromise. It is also in agreement with clinical and pathologic evidence that myocardial disease affects primarily the left side of the heart. Since cardiac output was measured in only four of these patients it cannot be stated whether or not decreased cardiac output and then decreased preload to t.he right ventricle resulted in normal right ventricular volume. However, the finding of normal or increased right ventricular stroke volume is evidence against this premise. In summary, we have shown that a simple geometric model can be used to determine angiographic right ventricular volume with accuracy and that the results correlate well with those obtained utilizing Simpson’s rule. The normal right ventricle is slightly larger than the left and has a lower ejection fraction. In chronic pressure load or increased afterload, the right ventricle tends to be smaller than normal and ejection fraction is increased. In chronic volume load or increased preload it is larger than normal but has a normal ejection fraction. In ventricular septal defect, tetralogy of Fallot and myocardial disease, the right ventricle is generally normal in size. Acknowledgment We gratefully acknowledge the assistance of Dr. F. A. 0. in preparation of the casts. We also thank Mr. Frank Domanszky, Ms. Audra Jarasius, Ms. Marilyn Williams and Mr. William Johnson for expert technical assistance.
Eckner
References 1. Graham TP Jr, Jarmakani JM, Atwood GF, et al: Right ventricular volume determinations in children. Normal values and observations with volume or pressure overload. Circulation 47:144153,1973 2. Gentzler RD, Brlselll MF, Gaulf JH: Angiographic estimation of right ventricular volume in man. Circulation 50:324-330. 1974 3. Glagov S, Echner FAO, Lev M: Controlled pressure fixation apparatus for hearts. Arch Pathol 76:640-646, 1963 4. Dodge HT, Sandler H, Ballew DW, et al: The use of biplane angiocardiography for the measurement of left ventricular volume in man. Am Heart J 60:762-776, 1960 5. Graham TP Jr, Lewis BM, Jarmakani MM, et al: Left heart volume and mass quantitation in children with left ventricular pres-
sure overload. Circulation 41:203-212, 1970 6. Thilenlus OG, Arcllla RA: Angiographic right and left ventricular volume determination in normal infants and children. Pediatr Res 0167-74, 1974 7. Kennedy JW, Baxley WA, Figley MM, et al: Quantitative angiocardiography. I. The normal left ventricle in man. Circulation 34: 272-276, 1966 9. Arcilla RA, Tsai P, Thllenius 0, et al: Angiographic method for volume estimation of right and left ventricles. Chest 60:446-454, 1971 9. Graham TP Jr, Jarmakani JM, Canent RV Jr, et al: Left heart volume estimation in infancy and childhood: reevaluation of methodology and normal values. Circulation 43:695-904, 1971
July 1975
The American Journal 01 CARDIDLDGY
Volume 36
75
Right Ventricular Volume in Congenital Heart Disease
ELIZABETH
A.
FISHER,
MD
IRA W. DuBROW, MD ALOIS R. HASTREITER, MD, FACC Chicago, Illinois
From the Division of Pedllric Cardiology, University of Illinois Hospital and Abraham Lincoln School of Medicine, Chicago, Ill. This study was supported in part by The University of Illinois Foundation Goodenberger Medical Research Grant 2-44-33-66-3-14. Manuscript accepted November 26, 1974. Address for reprints: Elizabeth A. Fisher, MD, Department of Pediatrics, University of Illinois Hospital, 840 South Wood St., Chicago, III. 60612.
Methods for angiographic determination of right ventricular volume were compared in right ventricular cast studies and in vivo using a semiautomated Simpson’s rule, elliptical and rectangular cross sections and a simple geometric model, a prism with a triangular base. In cast studies excellent correlation coefficients were obtained for all three methods (I = 0.97 to 0.98). In vivo, excellent linear correlation was obtained when the methods were compared (r = 0.98 to 0.99, P
Simpson’s rule has been shown to be an accurate method for angiographic determination of right ventricular volume.1,2 This method has had limited clinical use and right ventricular volume data are scanty because of the time-consuming and tedious measurements and calculations required when the technique is performed manually. The purpose of this paper is threefold: (1) to describe a semiautomated system for right ventricular volume determination by Simpson’s rule; (2) to compare this system with a simple geometric model used as a basis for simplified manual right ventricular volume determination; and (3) to present right ventricular volume data in a large group of infants and children, with both normal and abnormal right ventricles. Methods Ventricular Volume Determinations Right ventricular casts: Radiopaque plastic casts of dog, monkey, baboon and lamb hearts were made, utilizing Batson’s no. 17 Anatomical Corrosion Compound (Polysciences, Inc., Rydal, Pa.). Forty-eight casts with right
July 1975
The American Journal of CARDIOLOGY
Volume 36
67
RIGHT VENTfWLfLAR
VOLUME IN CHILDREN-FISHER
ET AL.
ventricles ranging in volume from 0.36 to 95.48 cc were prepared. The hearts were pressure-fixed3 and injected with the partially polymerized liquid mixed with barium sulfate paste to make it radiopaque. After the casts hardened the heart tissue was dissected free, the residual tissue was digested with concentrated potassium hydroxide solution, and the respective chamber casts were cut apart. True volumes were determined by water displacement. Radiographic volumes were determined from biplane frontal and lateral radiographs of the casts placed in anatomic position. The films were projected and the cast outlines traced by hand on paper. Plastic grids with 1 by 1 cm lead lines were radiographed at the center of each cast in both projections for purposes of correction for X-ray magnification. Simpson’s rule: Volumes were calculated by Simpson’s rule, assuming the cross-sectional areas to be either elliptical or rectangular. Manually, the drawings of the frontal and lateral projections were divided into 10 equally spaced sections by 11 horizontal lines. The volume of each section was ?r - X/2 - Y/2 . h for the elliptical cross section (where X is the frontal diameter and Y is the lateral diameter of the ellipse and h is the height of the section). For the rectangular cross section, the volume of each section was X . Y - h (where X is the frontal length and Y the lateral length of the rectangle and h is the height of the section). The sections were then summed to give the volume of the solid, as
Th 7j-
2L, where Af is the area of the frontal projection, A1 is the area of the lateral projection and L is the average of the frontal and lateral lengths. Frontal length was measured as the length of a perpendicular drawn between two parallel lines that intersected the top and bottom of the frontal projection. Lateral length was measured from the top of the pulmonary valve to the apex of the lateral projection (Fig. 1B). Areas were determined by planimetry. For each method, calculated volumes were plotted against true volumes and a linear regression analysis was made. In vivo volume determinations: Right and left ventricular volumes were determined from biplane cineangiocardiograms performed as a part of routine diagnostic cardiac catheterization studies. All patients were studied in the postabsorptive state. Only patients older than age 6 months were sedated with use of meperidine (Demerolm), promethazine (Phenerganm) and methazine (Sparinem) in intramuscular doses of 0.5 to 1 mg/kg, 0.25 to 0.5 mg/kg and 0.25 to 0.5 mg/kg, respectively. For patients older than age 2 years, additional sedation with droperidol-fentanyl (Innova@), 0.025 cc/kg up to 1 cc intravenously, was given if required. Biplane cineangiocardiograms were filmed at 64 or 80 frames/set after the high speed injection of 1 to 2 cc/kg of contrast medium (Conray 400@) into the inferior vena cava or right atrium. Cycles with premature contractions were not used. The earliest cardiac cycle with sufficient contrast to allow accurate tracing of chamber outlines was utilized, and in most cases right and left heart volumes could be determined from the same injection. Correction was made for X-ray magnification by a grid system as described earlier. Comparison of right and left ventricular volumes: Left ventricular volumes were determined by the standard Dodge biplane method,4 assuming the left ventricle to be an ellipse of revolution. The volume was calculated as 4rl 3.L1/2.L2/%L3/2, where L1 = the longer of two lines drawn from the center of the aortic valve to the apex in the frontal and in the lateral projections, Lp = the short axis of the frontal projection and L3 = the short axis of the lateral projection. L1 was measured directly; Lz and L3 were calculated by the formulas: L2 = 4Af/7rLl and Ls = 4Al/~L1, where Af and A1 are the areas of the frontal and lateral projections of the ventricle, respectively. Volumes were corrected by a regression equation determined from left ventricular cast studies: V’ - 0.85V, where V’ = corrected volume and V = calculated volume. As a test of the methods, angiographic stroke volumes of the right and left ventricles were compared in 91 infants and children with no shunts or valvular insufficiency. Right and left ventricular volumes and ejection fractions were also compared in two groups of patients believed to have normal right or left heart chambers (70 and 77 patients, respectively). Comparison of methods: Angiographic right ventricular volumes were determined by Simpson’s rule (semiautomated method), elliptical and rectangular cross sections and the prism method in 218 infants and children and the results compared after correction with the appropriate regression equations obtained from the cast studies.
1
[
;i’X,,Y,, + X,,,Y,,,)-t end segments (X,Y,
+
X,;Y ( +
odd-numbered
;(x?E’,
.
+
X,Y,J
+
X,Y,
+
even-numbered for the elliptical
+
cross-section
X,,,Y,,J
-t
segments
+
X,Y,)
1
segments
and
-t
end segments
(X,Y, + X,;Y,, + odd-numbered $XjY,
+ X,,Y,,) t
segments +
X,Y,
even-numbered
+
+ segments
X,\Y,,
1
for the rectangular cross section. By the semiautomated method, the drawings were traced with an electronic planimeter (Numonics Corporation, electronic graphics calculator) linked to a programming calculator (Wang 7OOC series) and plotting output writer (Wang 702 series). Using the X, Y coordinates the calculator was programmed to automatically divide the drawings by horizontal lines spaced at 5 mm intervals and to calculate the volumes by the formulas given above. Prism method: By inspection of the casts it was considered that a prism with a triangular base was the simpk geometric solid that most closely corresponded to the shape of the right ventricular casts. The frontal and lateral projections were assumed to be rectangular and to form the sides of a triangle in the horizontal plane. The model and derivation of the formula for its volume are shown in Figure 1A. Simplified, the formula is Af - Al/
68
July 1975
The American
Journal of CARDIOLOGY
Volume
Case
Material
Normal right ventricular volumes: Right ventricular volume was determined in 70 infants and children believed t,o have a normal right heart chamber. All patients in this group had a peak systolic pressure of less than 35 mm Hg and an end-diastolic pressure of less than 5 mm Hg in the
36
RlGHT VENT’RKXAR VDLLM
IN CMDREN-FISISR
ET AL.
FIGURE 1. Right ventricular model (A) and projections (B). Correspond-
ing measurements are indicated. 0 = average width in frontal plane; L = average length; W = average width in lateral plane. right ventricle. The group contained 31 patients with normal hemodynamic status studied because of arrhythmias, pulmonary disease, mediastinal masses, abnormal electrocardiograms or atypical murmurs. Nine patients had a small patent ductus arteriosus and five had undergone surgical closure of a patent ductus. Four patients had mild pulmonary stenosis (peak systolic gradient less than 15 mm Hg), 10 had mild to moderate aortic stenosis and 2 had undergone surgery for aortic stenosis. Five patients had mild to moderate mitral insufficiency, one mitral stenosis, one mild aortic insufficiency and two systemic hypertension. Their ages ranged from 0.5 to 21.75 years and body surface areas from 0.35 to 1.83 m2. Abnormal right ventricular volumes: Five groups of patients with an abnormal right ventricle were studied and the results compared with normal findings. Group 1 consisted of 44 patients with pulmonary stenosis. Ten of these had undergone surgery at least 1 year previously and had a residual peak systolic gradient from the pulmonary artery to the right ventricle of less than 20 mm Hg and a right ventricular peak systolic pressure less than 40 percent of systemic peak systolic pressure. Only one patient had radiographic cardiac enlargement postoperatively, and he had significant pulmonary insufficiency. The ages of the patients studied postoperatively ranged from 1.75 to 16.5 years and body surface areas from 0.51 to 1.73 ml. Of the 34 patients studied preoperatively, 20 had a pressure gradient of less than 50 mm Hg; the remainder (14 patients) had a gradient of 50 mm Hg or more. In 8 patients of this group peak right ventricular pressure was less than 40 percent of systemic, in 11 it was 40 to 60 percent, in 7 it was 60 to 100 percent and in 8 it was 100 percent of systemic pressure or greater. The ages of the patients studied preoperatively ranged from 0.75 to 23.0 years and body surface areas from 0.36 to 1.72 m2. Group 2 contained 21 patients with a left to right shunt at the atrial level. Eleven of these were studied preoperatively, nine with a secundum atria1 septal defect, one with a
primum atria1 septal defect and one with total anomalous pulmonary venous drainage. Their ages ranged from 0.83 to 16.67 years and body surface areas from 0.31 to 1.60 m*. Ten patients of this group were studied postoperatively, two who had undergone correction of total anomalous pulmonary venous drainage, one with repair of a secundum atria1 septal defect and seven with repair of a primum atrial septal defect. They were studied 0.17 to 5.0 years postoperatively, with seven studied 1 to 2 years postoperatively. Their ages ranged from 0.17 to 16.33 years and body surface areas from 0.34 to 1.70 mP. None had significant radiographic cardiac enlargement or residual lesions postoperatively. Group 3 contained 49 patients with a ventricular septal defect. Sixteen had a moderate to large subaortic defect with a pulmonary to systemic blood flow ratio greater than 1.5: 1. Fifteen had a small shunt with a pulmonary to systemic flow ratio less than 15: 1; two in this group had had a previous pulmonary arterial banding. The ages of these 31 patients ranged from 0.04 to 23.42 years and body surface areas from 0.20 to 1.87 mp. The remaining 18 patients in this group had undergone operation at least 1 year previously. Their ages ranged from 0.45 to 16.33 years and body surface areas from 0.45 to 1.60 m*. Only one had a large residual defect. Group 4 contained 22 patients with tetralogy of Fallot, II studied preoperatively and 11 studied at least 1 year after operation. In the patients studied postoperatively, ages ranged from 4.67 to 17.42 years and body surface areas from 0.75 to 1.89 m2. Two had significant pulmonary insufficiency, one manifesting radiographic cardiac enlargement. One postoperative patient had a residual ventricular septal defect with small left to right shunt, and one had significant residual pulmonary stenosis. In the patients studied preoperatively ages ranged from 0.17 to 5.33 years and body surface areas from 0.26 to 0.77 m2. Although one patient had significant pulmonary insufficiency, his heart size was radiographically normal.
July 1975
The Amerkan
Journal 01 CARDIOLOGY
Volwne 36
69
RKZHTVENTRKYJLAR VOLUME IN CHILDREN-FISHER ET AL.
TABLE
Regression
Analysis of Right Ventricular
Cast Studies
r Method
value
Simpson’s ellipse, manual Simpson’srectangle, manual Simpson’s ellipse, auto Simpson’s rectangle, auto Prism auto
calculation of small volumes. For the respective cross-sectional models (ellipse or rectangle), the regression equations for Simpson’s rule were quite similar using either the manual or semiautomated method. In vivo volume determinations-comparison of right and left ventricular volumes: There was a very high correlation between left and right ventricular stroke volumes in patients with no shunts or valvular insufficiency (r = 0.94, P
I
=
semiautomated
the estimate;
V = calculated
Regression Equation
SEE
0.97 0.97 0.97 0.97 0.98
5.79 5.79 3.77 3.76 2.94
method;
V’ V’ V’ V’ V’
SEE =
volume;
= = = = =
0.77v 0.6OV 0.71v 0.56V 1.16V
standard
V’ = corrected
- 2.92 - 2.99 - 1.15 - 1.15 - 1.04
error of volume.
Group 5 contained 12 patients believed to have myocardial disease. Ten had endocardial fibroelastosis, three with an associated tiny ventricular septal defect. Two had a primary cardiomyopathy (one due to Pompe’s disease and one of unknown origin). All had an abnormal electrocardiogram. Nine manifested left ventricular enlargement, one right ventricular enlargement, one combined ventricular enlargement and one Wolff-Parkinson-White syndrome, type B. Eight had radiographic cardiac enlargement, and six had hepatomegaly at the time of study. Eight had a history of congestive heart failure, but only three had failure at the time of study. Eight patients were receiving digoxin. At cardiac catheterization all standard hemodynamic measurements were normal in seven patients; four had elevated left ventricular end-diastolic pressure, one had elevated right ventricular end-diastolic pressure and one had elevated right and left ventricular end-diastolic pressures. Cardiac output, measured by the Fick method in only four patients, was normal. These patients’ ages ranged from 0.08 to 14.98 years and body surface areas from 0.2 to 1.54 m2.
Results Right ventricular casts: Regression analysis comparing true and calculated cast volumes (Table I) yielded high correlation coefficients for all methods. Standard errors were low for all methods and lowest (2.94) for the prism method. The Y intercepts for all methods were about 1 cc, making them applicable to
TABLE
II
Comparison
of Right and Left Ventricular
Volumes (ml) _---
Chamber
Reference
Age Group
Present
study
RV LV
Children Children
Graham Graham
et al.’ et aLy
RV LV
<1 yr/>l <2 yr/>2
Thilenius and ArcilIac
RV LV
<13 mo/>13 <13 mo/>13
Gentzler et al.’ Kennedy et al.:
RV LV
Adult Adult
EL&‘/m’
yr yr mo mo
ESV/m2
July 1975
The American Journal of CARDIOLOGY
25 19
39 40
0.61 0.68
39/70 42173
13125 13/27
26/45 29/46
0.66/0.64 0.68/0.63
64/78 43166
31/30 10/17
33148 34/48
0.52/0.61 0.79/0.74
39 24
42 45
0.51 0.67
81 70
Volume 36
EF
64 59
EDV/m’ = end-diastolic volume per square meter of body surface area; EF = ejection fraction; square meter of body surface area; LV = left ventricle; RV = right ventricle; SI = stroke index.
70
SI
ESV/m” = end-systolic
volume
per
RIGHT VENTRICULAR VOLUME H CfifLDREN-FISHER ET AL.
A
RVEDV, SIMPSON'S RULE vs PRISM METHOD NORMALS -
RVED",SIWSON'SICXLE "S PRISMMETHOD ABNOPnAL\
6
Y=I.OX-3.1 r-.98 N=149 sEt=6,8
+
++ + + + + +
+
+
+
SIMPSON'S 100: EDV(m1)
+ +++ /
‘/
;z__L____l____l____I____1____~____~____~____1
+____l____r____l____I--__r--_~___l_--_~
25
50
7s
100 125 PRISM EDV(ml)
+
150
175
.'5
200
50
li)O I.'5 1'10 Iii PRlSMll""("!l)
7'1
225
200
FIGURE 2. Comparison of right ventricular volumes calculated using Simpson’s rule, elliptical cross section, and the prism method in subjects with normal (A) and abnormal (6) conditions. EDV = end-diastolic volume; N = number of cases: RVEDV = right ventricular end-diastolic volume; SEE = standard error of the estimate; X = volume calculated by prism method: Y = volume calculated by Simpson’s rule.
pressed per square meter of body surface area, there remained a small but significant correlation with age (r = 0.40, P CO.01). Normal values for end-systolic volume/m2, stroke index and ejection fraction are given in Table III. Abnormal right ventricular volumes: The data are summarized in Table III and shown graphically in Figures 3 to 7. In Group 1 (pulmonary stenosis) values for mean end-diastolic volume/m2, end-systolic volume/m2 and stroke index were below normal (P
RVEDV s
BSA, PULMONARY STENOSIS
ZOO? , 175; , 1 150:' , ' 125:
/ /
RV/LV Pressure (%) x = less than 40 0 = 40-60 - = 60-100 .- 100 or more --_--_---_--_---_ * = postoperative
/
I
1
2
BSA(m')
FIGURE 3. Patients with pulmonary stenosis. Variation of right ventricular end-diastolic volume (RVEDV) with body surface area (BSA). Normal mean and 90 percent confidence limits are indicated by the solid and dashed lines, respectively. LV = left ventricular; RV = right ventricular.
umes and ejection fraction were normal. The one patient with an end-diastolic volume more than 2 standard deviations above the normal mean value had pulmonary insufficiency and radiographic cardiac enlargement. In Group 2 (atria1 left to right shunt) mean volumes were considerably above normal (end-diastolic volume/m2, P
July 1975
The American Journal of CARDIOLOGY
Volume 36
71
61 + 31 65 f 23 NS
77 3: 40 79 = 38 NS
S P D
S P D
S P D
S P D
11
31
11
12
ASD
VSD
ToF
MY0
I:
37 2. 27 39 7 27 NS
. .
NS NS .
NS NS .
NS NS
~0.050 .::0.025
~‘0.025 *-0.050 ..
P
39 I 17 38 i 19 NS
38 = 21 42 3. 16 NS
37 L 13 39 .+. 12 NS
62 I:. 24 65 .! 20 NS
34 i 11 34 .! 10 NS
39 :r 11 39 -: 10 NS
Mean :lSD
.
P
0.60 .r 0.07 0.60 -:. 0.06 NS 0.62 7 0.11 0.65 + 0.10 NS 0.56 + 0.13 0.51 I 0.15 NS
NS NS . . NS NS NS NS . .
P
NS <0.005
.
NS NS
NS NS
NS NS
GO.005 CO.010 .
-.
... ...
... ...
11 70 + 17 71 + 17 NS
18 66 r 15 67 +: 14 NS
..
NS NS
. .
NS NS
.
31 i 14 31 3. 13 NS
28 L 9 30 ,c 12 NS
NS NS
NS NS .
NS ~0.050
NS NS
P
ToF = Tetralogy
.
Mean 1-k SD
EF
0.11 0.10
...
NS NS
NS <0.05
NS NS
NS NS
...
P
...
-I
VSD = ventricula
NS = not significant;
0.57 * 0.57 * NS
0.57 + 0.07 0.56 z 0.10 NS
0.65 -:: 0.08 0.63 z 0.05 NS
0.61 T 0.09 0.61 z 0.07 NS
of Falfot:
N = normal;
40 t 10 40 1 10 NS
37 -7 9 37 I. 9 NS
46 .L 11 48 : 11 NS
37 :L 13 40 T 13 -.:0.050
1-L SD
Mean
SI (ml)
Postoperative
disease;
NS NS ...
NS NS ...
NS NS ...
25 - 7 28 f 7 NS
10 71 .r 14 75 T 16 NS
NS NS
24 + 10 NS 26 i. 10 NS NS .
10 61 i. 20 NS 66 + 20 NS co.025
.
P
...
... ... ...
Mean 1 :I- SD
-. ESV/rn? (ml)
.
... ... ...
no.
EDV/m? (ml) _. Mean .: 1 SD P -
Myo = myocardial rule and by prism method; S = Simpson’s rule; SD = Standard deviation;
0.56 .!- 0.11 0.57 Y- 0.08 NS
0.67 -‘. 0.09 0.65 T 0.09 .:.0.050
0.61 T 0.08 0.61 + 0.07 NS
Mean -2. 1 SD
EF
.
~0.025 ~‘0.050
SI (ml)
ASD = atrial left to right shunt; D = difference between volumes by Simpson’s P = prism; P = significance of difference from normal; PS = pulmonary stenosis; septal defect.
NS NS ...
NS 221 13 23 t 10 NS
NS NS ...
8
24 26’
NS NS .
i 8
46 12 48 .: 13 NS
..
17 ‘. 7 18 .r 7 ‘TO.010
25.j 8 25 -L- 7 NS
: 1SD
Mean
ESVjm? (ml)
...
. ..
__~_
_---
61 -t 19 65 = 18 <0.025
109 I: 28 114 L 27 NS
50s 15 53 7 14 CO.050
S P D
34
PS
64 i 15 64 + 15 NS
Mean 4 1 SD
70
S P D
no. Method
N
Group
EDV/m’ (ml)
Preoperatrve
P
1
1 -n
k 2
Right Ventricular -
Volumes
3
III
TABLE
RtCHT VENTROJLAR VOLUME H CHILDREN-FISHER ET AL.
Group 3 (ventricular septal defect) had normal mean volumes with no difference found between patients with a large or small shunt or those studied before or after operation. The two patients with pulmonary arterial banding had low normal volumes. In Group 4 (tetralogy of Fallot) the mean volumes both pre- and postoperatively were normal. One patient studied preoperatively had an end-diastolic volume more than 2 standard deviations above the normal mean value (124 ml/m2). He did not have radiographic cardiac enlargement, but his right ventricular end-diastolic pressure was elevated for age (8.6 mm
Hg). A second patient studied preoperatively had high normal end-diastolic volume (94 ml/m2). He had moderate pulmonary insufficiency, but his end-diastolic pressure and radiographic heart size were normal. The one patient studied postoperatively with an end-diastolic volume/m2 slightly above 2 standard deviations from the normal mean value (95 ml) had significant pulmonary insufficiency. Ejection fraction was decreased in this patient (0.36) and in one other patient studied postoperatively (0.41). In neither one was heart size increased radiographically. Two other patients studied postoperatively had an end-diastolic
RVDV
NED" ys BSA, ATRIAL SEPTAL DEFECT
/ 9
BSA,
VENTRICULAR
SEPTAL
DEFECT
1 I t
0
2,o; 1754
vs
230;
225;
o=preoperative *=postoperative
175f
/
R
1 1
/ 150;
/
x=small +=pulmonary
artery
band
*=postoperative
1 RSA
fn?)
2
1
FIGURE 4. Patients with an atrial septal defect (atrial left to right shunt). Variation of right ventricular end-diastolic volume with body surface area. Conventions as in Figure 3.
I
./
o=large
RSAlm2) __~_\_.. ,
FIGURE 5. Patients with a ventricular septal defect. Variation of right ventricular end-diastolic volume with body surface area. Conventions as in Figure 3. RVEDV y> BSA, MYOCARDIALDISEASE 251Ji
KVEDV vs BSA, TETRALOGY OF FALLOT 200;
1751
o=preoperative
207:
*=postoperative
150;
/
/
/
,‘____P_‘I____L______r___________________L 1
.?
1 BSA(m2)
BSA(m2)
FIGURE 6. Patients with tetralogy of Fallot. Variation of right ventricular end-diastolic volume with body surface area. Conventions as in Figure 3.
2
FIGURE 7. Patients with myocardial disease. Variation of right ventricular end-diastolic volume with body surface area. Conventions as in Figure 3.
July 1975
The American Journalof CARDIOLOGY
Volume 36
73
RIGHT VENTRICULAR VOLUME IN CHILDREN-FISHER
ET AL.
volume at the upper limits of normal (94 and 91 ml/ m2, respectively). Both had moderate pulmonary insufficiency, and one had cardiac enlargement by X-ray examination. In Group 5 (myocardial disease) mean end-diastolic volume/m2, mean end-systolic volume/m2 and mean ejection fraction were normal. Only two patients in this group had an end-diastolic volume more than 2 standard deviations above the normal mean value (135 and 161 ml/m2, respectively). Right ventricular stroke volume was increased in the former, patient (65 ml/m2). That patient had a normal ejection fraction (0.52), but ejection fraction was decreased (0.34) in the other. Corresponding left ventricular values for these patients were: end-diastolic volume/m2 203 and 219 ml, stroke index 76 and 57 ml, ejection fraction 0.37 and 0.36 and end-diastolic pressure 26 and 10 mm Hg. Cardiac output (Fick method) was 4.9 liters/min per m2 in the second patient, and 2.9 liters/min per m2 (with use of an assumed oxygen consumption) in the first patient. The second patient had elevated right ventricular enddiastolic pressure (10 mm Hg). Both had clinical evidence of right-sided heart failure with hepatomegaly. The first patient had massive mitral insufficiency believed to be secondary to cardiac dilatation. Discussion
The use of an electronic planimeter linked to a programming calculator and output writer greatly facilitates the application of Simpson’s rule to right ventricular volume determination. It is comparable in accuracy to the manual method, but the equipment is expensive and is not available in most laboratories. Therefore, Simpson’s rule remains limited in its clinical usefulness. The prism method requires no such equipment, the measurements are easily made manually and the calculations are quite simple. Objections to the use of a geometric model have been raised on the basis that it is less accurate than Simpson’s rule. However, in a previous report2 comparing Simpson’s rule with a geometric model in right ventricular case studies, little difference was shown in r values between the methods. No in vivo volume data were presented. Arcilla et al.” and Thilenius and Arcillas used a geometric model but did not compare results with Simpson’s rule. Graham et al.’ compared Simpson’s rule with two geometric models, finding little difference in the cast studies; they did not present a comparison of in vivo volumes by the various methods. Our investigation indicates that a simple geometric model, a prism with a triangular base, can be compared in accuracy with Simpson’s rule both in cast studies and in in vivo volume calculations. Normal Ventricular
Volumes
In comparing our right and left heart volumes we found the right ventricle to be slightly larger and to have a lower ejection fraction than the left. Other studies, one in infants and children” and another in adults,2,ga have found the same relation between the
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The American Journalof CARDIOLOGY Volume 36
right and left ventricles, but Graham et al.‘ps did not demonstrate any such differences in their studies (Table II). Although further data are needed to clarify this issue, it appears that the right ventricle is slightly larger than the left. Our normal data are comparable with those of previous reports, ls6 but we failed to demonstrate significantly lower volumes in infants. However, our youngest “normal” patient was 6 months old and only 7 of the 70 patients were less than 1 year of age, whereas in Graham’s study 6 patients were 5 months of age or younger and 7 of 16 in the normal group were less than 1 year of age. After normalization of volumes for body surface area, there remained a significant positive correlation with age. This observation is in agreement with other investigators’ findings of smaller volumes in young infants. Also, in this regard, Gentzler et a1.2 reported in adults with normal right heart chambers higher values than those reported by other&T6 in children. Abnormal
Right Ventricular
Volumes
Pulmonary stenosis: In contrast to Graham et al.,’ we found a small but definite decrease in mean right ventricular volume and stroke index, plus increased ejection fraction, in patients with pulmonary stenosis. Similar changes have been reported in left ventricular volume and ejection fraction in pediatric patients with aortic stenosis.” The right ventricle, as well as the left, is capable of ejecting an increased fraction of its volume of blood when exposed to a chronic increase in afterload. Whether this is due to increased contractility or to muscular hypertrophy remains to be investigated. The finding of normal mean volumes and ejection fraction in postoperative patients in this group lends support to the presence of a reversible adaptation to increased afterload in these patients. The individual patient in the postoperative group with increased volume had increased preload; thus, his condition was analogous to that of patients in Group 2 (atria1 left to right shunt). Gentzler et a1.2 described only two adult patients with pulmonary stenosis, both of whom had low values for end-diastolic volume (more than 2 standard deviations below the normal mean value in one). Both had a normal ejection fraction. Whether or not long-term pressure load of the right ventricle leads to compromise of function remains to be studied. Atria1 septal defect: Demonstration of’ a large increase in right ventricular volume in atria1 left to right shunt is in agreement with findings by Graham et al.’ in atria1 septal defect and total anomalous pulmonary venous drainage and by Gentzler et al.” in patients with tricuspid insufficiency and atria1 septal defect. Decreased ejection fraction in the patients in the latter study may have been due to long-term volume overload (increased preload) or to coronary artery disease or myocardial disease of other causes. In the absence of other such factors the right ventricle adapts to increased preload by increased end-diastolic and end-systolic volumes as well as increased
RM
stroke index, probably through the Starling mechanism. The finding of normal or nearly normal volumes postoperatively is evidence for a reversible adaptation to increased preload in children. Ventricular septal defect: No data are available on in vivo right ventricular volume in ventricular septal defect in children. Gentzler et a1.2 reported findings in two adult patients with a ventricular septal defect, one of whom also had right ventricular hypertension. Right ventricular volume was increased in the latter patient and normal in the other. In our group of 34 patients ventricular septal defect did not in most cases result in volume overload of the right ventricle. It may be that the site of the defect (in our study group all moderate to large defects were subaortic) results in shunting directly from the left ventricle to the pulmonary artery without overloading the right ventricle. Patients with a large muscular ventricular septal defect might then be expected to have an enlarged right ventricle. Tetralogy of Fallot: Patients with tetralogy of Fallot generally have normal heart size by X-ray examination, and this correlates well with our finding of normal mean right ventricular volume in this group. The lesion is a complex one and may, in the evolution of the disease, present predominantly a volume or a pressure load to the right ventricle. In general, the latter predominates and the right ventricle responds by hypertrophy but not enlargement. In the group of patients studied, right ventricular volume tended to be high normal or increased in the presence of pulmonary insufficiency, a situation resulting in increased preload.
VENTfMXJLAR VOLUME IN CHILDREN-FISHER
ET AL.
Myocardial disease: Our finding of normal mean right ventricular volume in patients with myocardial disease is in accord with similar findings by Gentzler et a1.2 in 7 of 13 patients with myocardial compromise. It is also in agreement with clinical and pathologic evidence that myocardial disease affects primarily the left side of the heart. Since cardiac output was measured in only four of these patients it cannot be stated whether or not decreased cardiac output and then decreased preload to t.he right ventricle resulted in normal right ventricular volume. However, the finding of normal or increased right ventricular stroke volume is evidence against this premise. In summary, we have shown that a simple geometric model can be used to determine angiographic right ventricular volume with accuracy and that the results correlate well with those obtained utilizing Simpson’s rule. The normal right ventricle is slightly larger than the left and has a lower ejection fraction. In chronic pressure load or increased afterload, the right ventricle tends to be smaller than normal and ejection fraction is increased. In chronic volume load or increased preload it is larger than normal but has a normal ejection fraction. In ventricular septal defect, tetralogy of Fallot and myocardial disease, the right ventricle is generally normal in size. Acknowledgment We gratefully acknowledge the assistance of Dr. F. A. 0. in preparation of the casts. We also thank Mr. Frank Domanszky, Ms. Audra Jarasius, Ms. Marilyn Williams and Mr. William Johnson for expert technical assistance.
Eckner
References 1. Graham TP Jr, Jarmakani JM, Atwood GF, et al: Right ventricular volume determinations in children. Normal values and observations with volume or pressure overload. Circulation 47:144153,1973 2. Gentzler RD, Brlselll MF, Gaulf JH: Angiographic estimation of right ventricular volume in man. Circulation 50:324-330. 1974 3. Glagov S, Echner FAO, Lev M: Controlled pressure fixation apparatus for hearts. Arch Pathol 76:640-646, 1963 4. Dodge HT, Sandler H, Ballew DW, et al: The use of biplane angiocardiography for the measurement of left ventricular volume in man. Am Heart J 60:762-776, 1960 5. Graham TP Jr, Lewis BM, Jarmakani MM, et al: Left heart volume and mass quantitation in children with left ventricular pres-
sure overload. Circulation 41:203-212, 1970 6. Thilenlus OG, Arcllla RA: Angiographic right and left ventricular volume determination in normal infants and children. Pediatr Res 0167-74, 1974 7. Kennedy JW, Baxley WA, Figley MM, et al: Quantitative angiocardiography. I. The normal left ventricle in man. Circulation 34: 272-276, 1966 9. Arcilla RA, Tsai P, Thllenius 0, et al: Angiographic method for volume estimation of right and left ventricles. Chest 60:446-454, 1971 9. Graham TP Jr, Jarmakani JM, Canent RV Jr, et al: Left heart volume estimation in infancy and childhood: reevaluation of methodology and normal values. Circulation 43:695-904, 1971
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