Echocardiographic volumetry of the right ventricle

Please see page 15 for the article by Kovalova et al. (doi:10.1016/j.euje.2004.04.009) to which this editorial pertains. Analyzing right ventricular (RV) volumes, mass and function has remained a challenge in clinical practice, 1 while the relevance for obtaining accurate, reproducible data has augmented with increased numbers of patients with Grown Up Congenital Heart (GUCH) disease and acute and chronic pulmonary abnormalities. 2 In comparison to the left ventricle, the right ventricle has a complex shape with different anatomical portions which contribute to the stroke volume (SV) to a variable extent. Invasively, angiography, thermodilution and conductance catheter techniques can provide absolute volumes and stroke volume, but they are inappropriate for repeated follow-up. The non-invasive modalities that are available today are echocardiography, 3 nuclear (SPECT and PET), magnetic resonance and multi-slice CT (MSCT). While the general advantages and disadvantages of these modalities are very well known to the readers of the Journal, it might be worthwhile to recall the ones that are specific for the right ventricle. 2D echocardiography has difficulties to image all the different portions of the right ventricle in perpendicular views, making it difficult to adopt a simple geometric model like for the left ventricle; 3D echocardiography 4,5 makes it possible to visualize the entire right ventricle and to reslice it in short axis cuts but resolution and wall delineation of these reconstructed images has only recently become acceptable; nuclear techniques 6–8 suffer from lack of spatial resolution and overlap with left ventricular structures, but adequate results have been obtained; MR 9,10 and CT 11–13 provide full coverage with good wall delineation which makes it possible to use Simpson's slice addition scheme. All techniques, however, struggle with the heavy trabeculation of the right ventricle and with the demarcation of the valvular structures; it is impossible to “catch” the large tricuspid valve in 3D, making a linear/planar separation at the valve plane necessary which introduces an inevitable error: the shape of the tricuspid valve differs significantly between end diastole and end systole. It is extremely difficult to delineate the trabeculations, either by hand or automatically, so one cannot include them for mass calculations and exclude them for volumetric measurements, as it is done for the left ventricle. Since the thickness of the wall is only 2–3mm in normal hearts, measuring RV mass is beyond the spatial resolution of current techniques and can only be accomplished reliably in RV hypertrophy. Finally, one could challenge the entire concept of defining RV function by volumetric measurements since both tricuspid insufficiency and pulmonary leaks are common in RV pathology and confuse the interpretation of a simple ejection fraction: effective ejection fraction, i.e. the effective SV (SV minus pulmonary insufficiency volume) divided by end-diastolic volume could be a better parameter but this requires the measurement of flow across the pulmonary valve during both systole and diastole.