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Circ J 2002; 66: 605 – 609
Right Ventricular Ejection Function
Assessed by Cineangiography
Importance of Bellows Action
Masahito Sakuma, MD; Hidehiko Ishigaki, MD;
Kohtaroh Komaki, MD; Yoshichika Oikawa, MD; Atsushi Katoh, MD;
Makoto Nakagawa, MD; Hidenari Hozawa, MD; Yoshito Yamamoto, MD;
Tohru Takahashi, MD; Kunio Shirato, MD
The right ventricular ejection fraction (RVEF) can be shown theoretically as a mathematical function of the
percent shortening in the 3 axial dimensions of the right ventricular cavity (the septum – free wall dimension
(SF), the anterior – posterior dimension (AP), and the tricuspid valve – apex dimension (TA) or the long axis
dimension (LA)). There is a need to decide which mechanism is the most important for the RVEF in cases with
neither obvious regional wall motion abnormalities of the left ventricle nor right ventricular overload. Forty-four
consecutive subjects (34 males/10 females) were enrolled: 16 had normal hemodynamic parameters without
significant coronary artery stenosis, 15 had hypertrophic cardiomyopathy and 13 had dilated cardiomyopathy.
Biplane right ventricular cineangiography was performed and the percent shortening of the SF, AP, and TA or
LA were measured. The percent shortening in the SF (34.8±14.7%) was larger than that of the AP, TA, and LA
(23.2±8.5, 21.0±8.3 and 18.3±7.0, respectively; all p<0.001). There was a linear correlation between the percent
shortening of each dimension and the RVEF. The 95% confidence interval of the regression equation from the
percent shortening of the SF and RVEF was located above those from the other percent shortenings, except for a
lower RVEF. These results indicate that systolic shortening of the SF (ie, bellows action) plays an important role
in the RVEF except for a lower ejection fraction. (Circ J 2002; 66: 605 – 609)
Key Words: Dimensions; Ejection fraction; Percent shortening; Right ventricle
R
ushmer et al used fluorography of the canine heart
to describe the 3 mechanisms responsible for
ejecting right ventricular blood and thought that
compression of the right ventricular chamber (ie, bellows
action) is the most effective maneuver.1–3 However, there
has not been a report of this in humans. Two-dimensional
(2-D) echocardiography and radionuclide angiography can
measure the right ventricular volume and ejection fraction
(RVEF), but are less useful for evaluating the mechanism
of right ventricular blood ejection.4–14 We reported that the
RVEF is a mathematical function of the percent shortening
of the 3 axial dimensions of the right ventricle15 and our
present study examines the importance of the bellows action
in the human right ventricle without obvious regional wall
motion abnormalities of the left ventricle or right ventricular overload.
parameters without significant coronary artery stenosis, 15
had hypertrophic cardiomyopathy and 13 had dilated cardiomyopathy. All patients were in normal sinus rhythm.
Procedures
Routine left and right catheterization was performed
Methods
Subjects
Forty-four consecutive persons (34 males/10 females;
mean age, 49.2 years (range, 16–74)) underwent diagnostic
catheterization: 16 had chest pain and normal hemodynamic
(Received November 30, 2001; revised manuscript received March
11, 2002; accepted March 15, 2002)
Department of Cardiovascular Medicine, Tohoku University Graduate
School of Medicine, Miyagi, Japan
Mailing address: Kunio Shirato, MD, Department of Cardiovascular
Medicine, Tohoku University Graduate School of Medicine, 1-1
Seiryo-Machi, Aoba-Ku, Sendai, Miyagi 980-8574, Japan
Circulation Journal Vol.66, June 2002
Fig 1. Representative biplane right ventriculogram (A,B) and schema
(C, D). RAO, right anterior oblique view; LAO, left anterior oblique
view; SF, septum – free wall dimension; AP, anterior– posterior dimension; TA, tricuspid valve – apex dimension; LA, long axis dimension;
MP, the mid-point of a line connecting the left ventricular side of the
pulmonary artery valve and the right ventricular apex in LAO view; S,
septum end of SF; F, free wall end of SF. See text for details.
606
using a standard technique. After the left ventricular cineangiography and coronary angiography, biplane right ventricular cineangiography was performed with 35-mm cine film
at a rate of 50 frames per second in a steep left anterior
oblique view and a right anterior oblique view projection
perpendicular to this projection using a Nishiya’s catheter
via the right femoral vein. We chose the angle of the left
anterior oblique view in which the interventricular septum
was seen best by biventriculography. Using this method,
the angle of the left anterior oblique view was 45 degrees in
41 patients and 30 degrees in 3. In this projection, the 2
bent portions of the Nishiya’s catheter appeared to overlap
closely as if in one straight line (Fig 1). Shallow spontaneous breathing was permitted during the right ventriculography to avoid the Valsalva maneuver. Contrast medium
(iopamidol 75.52%) was injected into the right ventricle
through the catheter at a rate of 12–13 ml/s for 3 s.
Data Analysis
Frames from 1 cardiac cycle of the right ventriculogram
from the electrocardiographic P wave to behind the next P
wave were analyzed. The right ventricular silhouette on each
frame of the biplane right ventriculogram was projected
and its outline was determined visually and traced by hand.
The obtained outline of the right ventricular chamber was
then digitized with a magnetic cursor (KD 4300; NEC,
Tokyo, Japan) and the geometric data were stored on a
Fig 2. Relationship between right ventricular (RV) ejection fractions
(EF) derived from % shortening of the RV dimensions, and calculated
by right ventricular end-diastolic and end-systolic volumes. See Fig 1
for abbreviations.
SAKUMA M et al.
floppy disk. The right ventricular volume was calculated
using Simpson’s rule and converted to the true volume by
the equation of Ishigaki et al:15 y = 0.87x – 4.8, where x is
the volume (ml) by Simpson’s rule and y is the true right
ventricular volume (ml). From this analysis, we drew a
volume – time curve for the right ventricle over one cardiac
cycle, and determined the right ventricular end-diastolic
volume at the maximal volume and the right ventricular
end-systolic volume at the minimal volume.
The 4 right ventricular dimensions (Fig 1) were determined by the same method as in the previous report.15
(1) In the left anterior oblique view, the septum – free
wall dimension (SF) was defined as the distance between
the right ventricular septum (S) and the free wall (F), crossing perpendicular to a line connecting the left ventricular
side of the pulmonary artery valve and the right ventricular
apex at the mid-point (MP) of this line.
(2) In the right anterior oblique view, the long axis
dimension (LA) was defined as the distance from the midpoint between the anterior side of the pulmonary valve and
the inferior side of the tricuspid valve to the right ventricular apex.
(3) In the right anterior oblique view, the anterior –
posterior dimension (AP) was determined as the distance
from the anterior wall to the inferior wall crossing the midpoint of the long axis dimension, parallel with the line
between the anterior side of the pulmonary valve and the
inferior side of the tricuspid valve.
(4) In the right anterior oblique view, the tricuspid
valve – apex dimension (TA) was determined as the distance
between the mid-point of the tricuspid valve to the right
ventricular apex.
Furthermore, to assess the motion of the SF, it was
divided into 2 parts that were the distance from the right
ventricular free wall to the mid-point of the left ventricular
side of the pulmonary valve and the right ventricular apex
(F-MP), and the distance from the right ventricular septum
to the mid-point (S-MP) (Fig 1).
In each dimension, we measured the end-diastolic
dimension at the end-diastolic volume and the end-systolic
dimension at the end-systolic volume. Systolic movements
of the right ventricular free wall and ventricular septum
toward the right ventricular cavity were expressed as positive. As in the previous report,15 the intra-observer difference
in the volume measurements of several subjects was less
than 3% and the inter-observer difference was less than 6%.
Our previous study showed that the RVEF can be calculated using the dimensions of the 3 axes:
EF by shortening in 3 axes = 100 –
(100 – % shortening(1)) × (100 – % shortening(2)) ×
(100 – % shortening(3)) / 10,000
Equation (1),
Fig 3. Relationship between % shortening of dimension (panel A for
SF dimension; panel B for AP dimension; panel C for TA dimension;
panel D for LA dimension) and right ventricular ejection fraction. See
Fig 1 for abbreviations.
Fig 4. The 95% confidence interval of % shortening of the dimension at the relationship between % shortening of dimension and right
ventricular ejection fraction. See Fig 1 for abbreviations.
Circulation Journal Vol.66, June 2002
Right Ventricular Ejection Function
607
Table 1 Multiple Regression Analysis of Determinants of Right Ventricular Ejection Fraction 2 Sets of 3 Axes Dimensions
Coefficient
SEE
Std Reg Coeff
t
p value
R2
R*2
F
p value
Constant
%s of SF
%s of AP
%s of TA
25.2
0.59
0.32
0.27
2.67
0.062
0.118
0.127
25.2
0.7
0.21
0.18
9.45
9.62
2.66
2.11
<0.0001
<0.0001
0.011
0.041
0.836
0.823
67.73
<0.0001
Constant
24.5
(26.2)
0.63
(0.64)
0.39
(0.45)
0.18
2.97
(2.73)
0.060
(0.060)
0.111
(0.105)
0.127
24.5
(26.2)
0.75
(0.75)
0.27
(0.30)
0.1
8.25
(9.62)
10.54
(10.57)
3.51
(4.24)
1.4
<0.0001
(<0.0001)
<0.0001
(<0.0001)
0.001
(0.0001)
0.17
0.826
(0.817)
0.813
(0.808)
63.19
(91.62)
<0.0001
(<0.0001)
%s of SF
%s of AP
%s of LA
Values in parentheses are the results of select regression analysis incorporating only factors identified as significant. Std Reg Coeff, standardized regression
coefficient; R2, multiple correlation coefficient; R*2, coefficient of determination adjusted for the degree of freedom; %s, % shortening. See Fig 1 for other
abbreviations.
Table 2 Multiple Regression Analysis of the Determinants of the % Shortening of the Septum-Free Wall
Constant
%s of F-MP
%s of S-MP
F-MP (ED)
S-MP (ED)
Coefficient
SEE
Std Reg Coeff
t
p value
R2
R*2
F
p value
5.38
(2.66)
1.36
(1.30)
0.38
(0.29)
–0.20
0.41
6.49
(2.03)
0.078
(0.073)
0.062
(0.047)
0.121
0.227
5.38
(2.66)
1.05
(1.00)
0.45
(0.35)
–0.10
0.12
0.83
(1.31)
17.5
(17.7)
6.07
(6.19)
–1.63
1.80
0.41
(0.20)
<0.0001
(<0.0001)
<0.0001
(<0.0001)
0.11
0.079
0.895
(0.884)
0.885
(0.879)
83.40
(156.60)
<0.0001
(<0.0001)
F-MP, distance from the right ventricular free wall to the mid-point of the left ventricular side of the pulmonary valve and the right ventricular apex; S-MP,
distance from the right ventricular septum to the mid-point in Fig 1; ED, end diastole. See Fig 1 and Table 1 for other abbreviations.
where EF is the ejection fraction and the added numbers
show the axis number, with the 3 axes being SF, AP and
TA or TA.
Statistics
All values are shown as mean ± standard deviation and
multiple comparisons were made by Scheffe’s method.
Linear relationships were fitted with a standard least squares
linear regression analysis. Variables were considered to be
significantly different at the level p<0.05.
Multiple linear regression analysis was used to test the
independent influences of % shortenings in each set of 3
dimensions on the RVEF. The general linear model used
was:
RVEF = C0 + C1 % shortening(1) + C2 % shortening(2)
+ C3 % shortening(3)
Equation (2)
with, a constant (C0) and 3 linear coefficients (C1 – C3). We
also examined the independence of the % shortening of the
F-MP and S-MP lengths, and end-diastolic lengths of F-MP
and S-MP on the % shortening of the SF dimension.
Results
In this series, there was also a close correlation between
the RVEF calculated from Equation (1) and that calculated
by the right ventricular end-diastolic and end-systolic
volumes (Fig 2).
The % shortening of the SF dimension (34.8±14.7%) was
larger than that of the AP, TA, and LA (23.2±8.5, 21.0±8.3
Circulation Journal Vol.66, June 2002
and 18.3±7.0, respectively; all p<0.001).
When SF, AP, and TA were used as the 3 axes dimensions, the % shortening of each dimension showed a linear
correlation with the RVEF (Fig 3A–C). The relation of the
% shortening of the 3 dimensions to the RVEF with a 95%
confidence interval (95% CI) is superimposed in Fig 4A.
The 95% CI of regression with the SF was located above
those with the 2 other dimensions except for the lower EF.
When the LA was used instead of the TA, there was a close
relation to the RVEF (Fig 3D) and the 95% CI of regression
with SF was also located above those of the 2 other dimensions (AP and LA) except for the lower EF (Fig 4B).
In multiple regression analysis, the % shortening of the
SF had the largest standardized regression coefficient for
the RVEF in both our sets of % shortening of the right
ventricular dimensions (Table 1).
The length of the F-MP and S-MP was 56.4±7.4 mm and
18.4±4.3 mm, respectively, and the % shortening of the FMP and S-MP was 27.7±11.2% and –9.8±17.5%, respectively. In multiple regression analysis of the determinant of
% shortening of the SF (Table 2), the % shortening of both
the F-MP and S-MP was significant. The % shortening of
the F-MP had a larger standardized regression coefficient
than the S-MP.
Discussion
In the present study, we chose 2 sets of 3 dimensions of
the right ventricle and assessed the contribution of the
shortening of each to the ejection of blood from the right
SAKUMA M et al.
608
ventricle, demonstrating that the systolic shortening of the
SF (ie, the bellows action) plays an important role in the
right ventricular ejection function except for the lower EF.
Rushmer et al described 3 mechanisms of blood ejection
from the right ventricle of the canine heart: movement of
the tricuspid valve ring toward the right ventricular apex,
compression of the right ventricular chamber (bellows
action), and traction on the right ventricular free wall by
contraction of the left ventricle.1–3
We chose the SF, AP, and TA as the 3 axes of the right
ventricle for comparison with the method proposed by
Rushmer et al, and the LA instead of the TA in another set
of 3 axes because these 3 axes are nearly perpendicular and
therefore easy to understand. The RVEF is a mathematical
function of the % shortening of the 3 axes (see Equation
(1));15 the equation has 3 independent variables that are
interchangeable with each other, which means that in this
mathematical model the contribution of the shortening of
each dimension to the EF is equivalent and that the degree
of % shortening itself indicates the magnitude of its contribution.
A simple comparison of the % shortening of the dimensions in the right ventricle showed that the systolic shortening of the SF is larger than that of the other dimensions.
Moreover, the % shortening in the SF against the RVEF was
larger than any other three except for the lower EF. Our
result in Fig 4 is comparable with that Smiseth et al16 and
together with our other findings leads to the conclusion that
systolic shortening of the SF (ie, the bellows action) plays
an important role in the right ventricular ejection function
except for the lower EF.
Another statistical approach, multiple regression analysis, was performed to assess the importance of % shortening
for the RVEF. The % shortening of the SF had the largest
standardized regression coefficient for the RVEF in both
our sets of % shortening of the right ventricular dimensions,
which further supports the importance of the bellows action.
The % shortening of the SF dimension can be mathematically shown by 4 parameters: the % shortening of the
length of both the F-MP and S-MP, and of their enddiastolic length. We used these 4 parameters for statistical
signification of the % shortening of the SF dimension,
which indicated that the % shortenings of the F-MP and
S-MP was significantly related to the % shortening of the
SF dimension, and that the correlation is strong especially
in the % shortening of the F-MP.
The importance of contraction of the right ventricular
free wall has been underestimated17 and passive conduit is
used instead of the native right ventricle in some congenital
heart diseases. However, an experimental study indicated
that contraction of the right ventricular free wall contributed
to maintenance of right ventricular ejection function.18
Active contraction of the free wall may result in a bellows
action, which of course may also be influenced by the
movement of the ventricular septum and indirectly by that
of the left ventricular free wall. In addition, it seems that
these myocardial movements depend on bi-ventricular pressures and volumes. In our present study, the bellows action
may be the most effective factor in right ventricular ejection, except for the lower EF, but we did not evaluate how
the bellows action relates to potential factors other than the
% shortening of F-MP and S-MP.
In the lower EF, there were no differences in % shortening between the dimensions of the right ventricle, which
may indicate that the right ventricle acts only as a conduit
in this situation.
Right ventricular regional wall motion has been assessed
by cineangiography,19–21 2-D echocardiography,5,22 radionuclide angiography23 and magnetic resonance imaging,24 but
none of these reports examined the direct relation between
the right ventricular global ejection fraction and regional
shortening. Our results suggest that the ejection function of
the right ventricle can be evaluated to some degree by the
% shortening of the SF dimension in cases without obvious
regional wall motion abnormalities of the left ventricle or
right ventricular overload. They also suggests that 2-D
echocardiography is a useful non-invasive means of assessing right ventricular ejection function.
Study Limitations
In the present study, there were no cases of coronary heart
disease, atrial septal defect or severe pulmonary hypertension in which other mechanisms may be major contributors
to maintaining right ventricular ejection. Therefore, regional
dysfunction of the right ventricle or right ventricular pressure and/or volume overload needs to be further investigated.
The AP dimension may partly reflect traction on the right
ventricular free wall by contraction of the left ventricle, one
of the mechanisms for right ventricular ejection, but other
imaging techniques are required to assess that.
References
1. Rushmer RF, Crystal DK. Changes in the configuration of the ventricular chambers during the cardiac cycle. Circulation 1951; 4:
211 – 218.
2. Rushmer RF, Thal N. The mechanics of ventricular contraction.
Circulation 1951; 4: 219 – 228.
3. Rushmer RF. Cardiovascular dynamics, 4th edn. Philadelphia:
Saunders; 1976: 91 – 93.
4. Tobinick E, Schelbert HR, Henning H, LeWinter M, Taylor A,
Ashburn WL, et al. Right ventricular ejection fraction in patients with
acute anterior and inferior myocardial infarction assessed by radionuclide angiography. Circulation 1978; 57: 1078 – 1084.
5. Bomer W, Weinert L, Neuman A, Neef J, Mason DT, DeMaria A.
Determination of right atrial and right ventricular size by two-dimensional echocardiography. Circulation 1978; 60: 91 – 100.
6. Maddahi J, Berman DS, Matsuoka DT, Waxman AD, Forrester JS,
Swan HJ. Right ventricular ejection fraction during exercise in normal
subjects and in coronary artery disease patients: Assessment by multiple gated equilibrium scintigraphy. Circulation 1980; 62: 133 – 140.
7. Slutsky R, Hooper W, Gerber K, Battler A, Froelicher V, Ashbern
W, et al. Assessment of right ventricular function at rest and during
exercise in patients with coronary heart disease: A new approach
using equilibrium radionuclide angiography. Am J Cardiol 1980; 45:
63 – 71.
8. Ninomiya K, Duncan W, Cook DH, Olley PM, Rowe RD. Right
ventricular ejection fraction and volumes after Mustard repair: Correlation of two-dimensional echocardiograms and cineangiograms. Am
J Cardiol 1981; 48: 317 – 324.
9. Brent BN, Berger HJ, Matthay RA, Mahler D, Pytlik L, Zaret BL.
Physiologic correlates of right ventricular ejection fraction in chronic
obstructive pulmonary disease: A combined radionuclide and hemodynamic study. Am J Cardiol 1982; 50: 255 – 262.
10. Silverman NH, Hudson H. Evaluation of right ventricular volume and
ejection in children by two-dimensional echocardiography. Pediatr
Cardiol 1983; 4: 197 – 203.
11. Detrano R, MacIntyer W, Salcedo EE, O’Donnell J, Underwood DA,
Simpfendorfer C, et al. Videodensitometric ejection fraction from
intravenous digital subtraction right ventriculograms: Correlation with
first pass ratio nuclide ejection fraction. J Am Coll Cardiol 1985; 5:
1377 – 1381.
12. Gibson TC, Miller SW, Artz T, Hardini NJ, Weyman AE. Method
for estimating right ventricular volume by planes applicable to crosssectional echocardiography: Correlation with angiographic formulas.
Am J Cardiol 1985; 55: 1584 – 1588.
13. Dell’Italia LJ, Starling MR, Walsh RA, Badke FR, Lasher JC,
Blumhardt R. Validation of attenuation-corrected equilibrium radio-
Circulation Journal Vol.66, June 2002
Right Ventricular Ejection Function
14.
15.
16.
17.
18.
nuclide angiographic determination of right ventricular volume:
Comparison with cast-validated biplane cineangiography. Circulation
1985; 72: 317 – 324.
Dell’Italia LJ, Lembo NJ, Starling MR, Crawford MH, Simmons RS,
Lasher J, et al. Hemodynamically important right ventricular infarction: Follow-up evaluation of right ventricular systolic function at rest
and during exercise with radionuclide ventriculography and respiratory gas exchange. Circulation 1987; 75: 996 – 1003.
Ishigaki H, Shirato K, Sakuma M, Oikawa Y, Katoh A, Nakagawa M,
et al. A new method for evaluating right ventricular dimensions and
volume by cineangiography. Tohoku J Exp Med 1996; 180: 289 – 296.
Smiseth OA, Frais MA, Kingma I, Smith ER, Tyberg JV. Assessment
of pericardial constraint in dogs. Circulation 1985; 71: 158 – 164.
Starr I, Jeffers WA, Meade R Jr. The absence of conspicuous increments of venous pressure after severe damage to the right ventricle of
the dog, with a discussion of the relation between clinical congestive
failure and heart disease. Am Heart J 1943; 26: 291 – 301.
Munakata K, Shirato K, Ishikawa K, Sakama M, Kanazawa M,
Haneda T, et al. Significance of the right ventricular free wall in dogs
with and without pulmonary constriction. Tohoku J Exp Med 1995;
Circulation Journal Vol.66, June 2002
609
177: 93 – 106.
19. Ferlinz J, Delvicario M, Gorlin R. Incidence of right ventricular asynergy in patients with coronary artery disease. Am J Cardiol 1976; 38:
557 – 563.
20. Sheehan FH, Bolson EL, Dodge HT, Mathey DG, Schofer J, Woo H.
Advantages and applications of the centerline method for characterizing regional ventricular function. Circulation 1986; 74: 293 – 305.
21. Maeda M, Yamakado T, Nakano T. Right ventricular diastolic function in patients with hypertrophic cardiomyopathy: An invasive
study. Jpn Circ J 1999; 63: 681 – 687.
22. Reynertson SI, Kundur R, Mullen GM, Costanzo MR, McKiernan TL,
Louie EK. Asymmetry of right ventricular enlargement in response
to tricuspid regurgitation. Circulation 1999; 100: 465 – 467.
23. Ratner SJ, Huang PJ, Friedman MI, Pierson RN Jr. Assessment of
right ventricular anatomy and function by quantitative radionuclide
ventriculography. J Am Coll Cardiol 1989; 13: 354 – 359.
24. Molinari G, Sardanelli F, Gaita F, Ottonello C, Richiardi E, Parodi
RC, et al. Right ventricular dysplasia as a generalized cardiomyopathy? Findings on magnetic resonance imaging. Eur Heart J 1995; 16:
1619 – 1624.