What is a ‘‘normal’’ right ventricle? Kovalova , *

Eur J Echocardiography (2006) 7, 293e297
What is a ‘‘normal’’ right ventricle?
Sylva Kovalova*, Josef Necas, Jaroslav Vespalec
Centre of Cardiovascular Surgery and Transplantation, Pekarska 53, 656 91 Brno, Czech Republic
KEYWORDS
Right ventricular
volumetry;
Right ventricular
ejection fraction;
2D Echocardiography;
Ellipsoidal shell model;
Normal values
Abstract Aims: The aim of this project was to define normal values of right
ventricular (RV) volumes and ejection fraction (EF) in healthy population using 2D
echocardiography.
Methods and results: The ‘‘patient’’ group comprised 91 healthy volunteers aged
17e62 years. RV volumetry was based on ellipsoidal shell model method. Left
ventricular (LV) volumes were assessed by Teichholz formula. All volumes were
indexed per m2 of BSA and the rate distribution of measured and calculated values
were evaluated. The normal range of individual parameters was expressed as mean
value G 2 standard deviations (d). A pair test was used to compare corresponding
results of the RV and LV measurements. The regression analysis was used to test the
relationship between LV and RV volumes and age. Indexed enddiastolic and
endsystolic RV volumes were 79.1 G 29.9 ml and 32.6 G 19.7 ml, respectively, EF
being 50 G 9.7% in men and 58 G 13.6% in women. No correlation with patient’s age
was observed.
Conclusion: Enddiastolic and endsystolic volumes of RV were significantly higher
than those of LV. EF of RV was lower as compare to LV. Right ventricular EF in men was
lower than that in women. There was no correlation between EF and patient’s age.
ª 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights
reserved.
Introduction
In daily echocardiographical practice there is
a need for exact quantification of right ventricular (RV) volumes (tricuspid and pulmonary regurgitation, interatrial shunts) as well as exact
* Corresponding author. Tel.: C420 5431 82530; fax: C420
5432 11218.
E-mail address: [email protected] (S. Kovalova).
assessment of right ventricular ejection fraction
(EF) (pulmonary hypertension, ischemic heart
disease, cardiomyopathies). There are two major
challenges: firstly, selection of the appropriate
method and secondly, the interpretation of the
results.
At present several methods enable non-invasive
quantification of RV volumes and EF (MRI,1e3
radionuclides4,5 and echocardiography6,7). There
is a little experience in RV volumetry generally.
1525-2167/$32 ª 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.euje.2005.06.010
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Received 5 April 2005; received in revised form 6 June 2005; accepted 15 June 2005
Available online 19 July 2005
294
S. Kovalova et al.
Figure 3 Distribution rate of indexed SVI of RV and LV
in healthy population.
Though MRI is considered the gold standard in RV
volumetry,1e3 the selection of preferred method is
influenced also by its availability, cost, patient’s
comfort and repeatability during follow-up, therefore echocardiography might be preferred. Our
experience as well as recent literature indicate
that echocardiography is a relatively easy and
reliable also in this respect.6,7
Concerning the interpretation of volumes and EF
of the RV, there is still lack of generally accepted
‘‘normal’’ values and there is also a wide range
variability of hitherto published data.1,4,5,8,9 The
aim of our study was to answer the question e what
are the ‘‘normal’’ values of volumes and EF of the
right ventricle as assessed by 2D echocardiography.
Right ventricular volumetry was accomplished
using ‘‘ellipsoidal shell model’’ with corresponding
formula V Z 2/3Pd. Area P was measured in
our modification of apical four-chamber view and
distance d in parasternal short axis. All measurements were performed in both systole and
diastole. The difference of enddiastolic (EDV)
and endsystolic volume (ESV) yielded stroke volume (SV). SV expressed as percentage of EDV
represents RV EF. Exact specification of projections and validation of the model and method used
was carried out on a group of 82 patients as
published before.7
All measurements were performed on SONOS
5500 (Agilent Technologies, Inc., Andover, Massachussetts) using S3 probe in harmonic imaging
mode.
The patient group consisted of 91 healthy
normotensive volunteers. Forty-six were men and
45 women with an average age of 39 years (range
17e62). All of them had a normal echocardiogram.
Their respective RV volumes and EF were calculated as mentioned above. Left ventricular volumes were calculated using commercial software
and Teichholz equation. All volumes were indexed
per m2 of BSA.
We analysed the distribution rate of all measured and calculated values as well as average
values and median. ‘‘Normal range’’ was defined
as mean value G 2d. Corresponding values of the
right and left ventricles were compared using a pair
Figure 2 Distribution rate of indexed ESV of RV and LV
in healthy population.
Figure 4 Distribution rate of EF of RV and LV in healthy
population.
Material and methods
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Figure 1 Distribution rate of indexed EDV of RV and LV
in healthy population.
What is a ‘‘normal’’ right ventricle?
295
Table 1 Indexed volumes and EF of RV and LV in
healthy population (mean value G 2 standard deviations)
EDVI (ml/m2)
ESVI (ml/m2)
SVI (ml/m2)
EF (%)
Right
ventricle
Left
ventricle
70.1 G 25.9
32.6 G 19.7
37.3 G 10.7
53.9 G 14.2
59.2 G 15.3
22.6 G 9.3
36.4 G 8.9
61.2 G 8.9
test. Statistical difference between right and left
ventricular EF was tested by Student t-test. The
correlation between the age and EF of respective
RV and LV was tested by regression analysis.
The distribution rate of values measured and
calculated (indexed EDV, ESV, SV and EF) of the
RV and LV approximately matches normal Gaussian
distribution (Figs. 1e4). The indexed values of RV
and LV volumes and EF are presented in Table 1.
The indexed EDV (EDVI) and ESV (ESVI) of the RV
were significantly greater than those of the LV
(pair t-test, a Z 0.1%). There was no significant
difference between indexed SV (SVI) of the RV and
LV. This supports the validity of the RV volumetric
method used. EF of the RV is significantly lower
than that of the LV (pair t-test, a Z 0.1%).
When comparing male and female patients,
EDVI and ESVI of the RV in males exceed significantly those in females, which in turn explains the
significantly lower RV EF in males as compare to
females (Fig. 5). In contrast LV EF in both males
and females did not show any significant difference (Table 2). RV and LV EF of the persons in our
study were not dependent on the age (Fig. 6).
Discussion
Evaluation of the RV function based on quantitative volumetry is superior to semiquantitative
Table 2
methods, however it requires solid methodology:
exact projections and accuracy in measurements.
Distribution of values of indexed ventricular volumes and EF in our study approached Gaussian
curve, which is typical for biological measurements. Minor deviations from ideal shape can be
explained by a relatively small number of persons
in study and inherent inaccuracy of measurements.
‘‘Normal values’’ of RV1,4,5,8e10 and LV1,4,5,11e16
volumes and ejection fraction appear rarely in the
literature. They usually are not the main aim of
the studies, but only represent some smaller
control groups evaluated by different methods.
Therefore, the results are very inconsistent and
vary widely. The ‘‘normal ranges’’ of averaged RV
volumes and EF by different authors are shown in
Table 3. Our results are within these ranges.
Similar to our results, all studies comparing RV
and LV volumetry by whichever method, found
higher estimates for RV systolic and diastolic
volumes than those of the LV.1,4,5
Systolic function of the ventricles is usually given
as their EF. The estimation of EF in LV is a standard
part of a routine echocardiographic examination. In
our study group the lowest value of LV EF was 50%.
Taking into account the accepted standard for
normal values expressed as average value G 2
standard deviations, the LV EF in our study
was 61.2 G 8.9%. The male subgroup did not
Indexed volumes and EF of RV and LV in healthy men and women (mean value G 2 standard deviations)
Men
2
EDVI (ml/m )
ESVI (ml/m2)
SVI (ml/m2)
EF (%)
Women
Right ventricle
Left ventricle
Right ventricle
Left ventricle
78.9 G 19.7
39.5 G 15.0
39.4 G 9.1
50.0 G 9.7
61.8 G 14.9
24.0 G 10.0
37.7 G 8.4
60.7 G 8.4
60.8 G 17.2
25.6 G 12.7
35.2 G 10.7
58.0 G 13.6
56.5 G 13.8
21.2 G 7.7
35.2 G 8.9
61.7 G 9.4
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Results
Figure 5 Distribution rate of EF of RV in healthy men
and women.
296
S. Kovalova et al.
a lower resting EF, which in fact represents
functional reserve in a trained person. Exact
explanation of the above relationship is beyond
this study and would require another specifically
aimed analysis.
Study limitation
Figure 6
Relation between EF of RV (LV) and age.
Table 3 Indexed ventricular volumes and EF e
range of mean values declared as ‘‘normal’’ by
various authors
2
EDVI (ml/m )
ESVI (ml/m2)
SVI (ml/m2)
EF (%)
‘‘Normal’’ range
Our measurements
LV
RV
LV
RV
52e87
14e35
18e52
59e74
63e103
22e56
40e41
43e65
59.17
22.64
36.42
61.20
70.0
32.6
37.31
53.91
Conclusions
Enddiastolic and endsystolic RV volumes are greater
than those of the LV, while RV EF is lower than that
of LV.
In our study the mean value of RV EF in males
was lower than in females.
Normal mean value of RV EF is 53.9%. The lower
range in males is 40% and in females 45%.
No relationship between RV EF and age in
healthy individuals was found.
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