Prof. Luigi Paolo Badano,
Prof Takeuchi raised the issue that the evaluation of the right ventricle (RV) by conventional (2D) echocardiography is very difficult, because of the peculiar geometry of this cardiac chamber, the lack of anatomical landmarks to orient the views and the changes of the shape with loading conditions. Conversely, volumetric acquisitions by 3D echocardiography are well suited for RV geometry and functional study. RV volumes and ejection fraction measured by 3DE have been validated against cardiac magnetic resonance. New and more user-friendly software packages are available to perform quantitative analysis of 3D data sets of the RV. Recently, the independent prognostic value of 3DE assessment of RV ejection fraction has been reported in consecutive patients with various cardiac conditions. The power of RV ejection fraction to predict cardiac mortality and MACE was higher than that of left ventricular ejection fraction.
Prof Badano described how to acquire good 3DE data sets to measure RV volumes and ejection fraction. The availability of a cut-out bed is a must in order to position the patient on the left side and the probe more lateral than usual when we acquire the left ventricle from the apical approach. The probe should be oriented to imagine the RV focused 4-chamber view in 2D. Then the 3D button is activated and the acquisition should be guided by the multislice display in order to ensure that the whole RV (particularly critical is the anterior wall which is the closest to the sternum) is included in the dataset. If not, small changes of the probe position/orientation, respiratory manoeuvre are usually enough to acquire good data sets in around 85%-90% of routine patients with RV volumes up to 300-350 ml. A stable ECG trace with a clearly identifiable R wave and a cooperative patient, who is able to hold his/her breath for a few seconds, are key to avoid stitching artefacts during multi-beat full volume acquisition
Dr Kovacs described the use of 3D data sets of the RV to obtain advanced data about the mechanics of RV function. With conventional 2D echo, we almost exclusively study the longitudinal shortening of the RV, underestimating the contribution of the other components of RV global function: transversal deformation (bellow effect), the bulging of the interventricular septum into the RV (interventricular interdependence) and RV outflow tract contraction. Using the meshes of the RV obtained by 3DE, we can measure the relative contribution of the longitudinal and the radial components to global RV function. In normal function, longitudinal and radial component contribute equally to global RV function. However, in disease states, the RV adapts differently to maintain the stroke volume. For example, in patients with RV pressure overload have a prevalent reduction of the radial function and rely mostly on the longitudinal function to maintain global RV ejection fraction. The opposite happens in patients with RV volume overload in whom the main mechanism to maintain RV stroke volume is the RV radial function
Dr Muraru showed the added value of 3D echocardiography in real clinical cases in which the conventional (i.e. 2D and TDI) parameters of RV function provided controversial results: patients after cardiac surgery or heart transplant, patients with chest deformities (pectus excavatum), suspected arrhythmogenic cardiomyopathy, and patients with pulmonary hypertension. She showed that the measurement of RV volumes and ejection fraction is both feasible and provides added clinical value to assess RV function, address management and patient prognosis
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