Imaging the right ventricle

The assessment of right ventricular (RV) volumes and function is fundamental to understand and manage congenital and acquired heart diseases. The growing interest in treatments designed to alter pathologic remodelling requires clinically applicable measurement of cardiac shape, volumes and function that are both accurate and reproducible. As well as providing important information at a single time point, serial assessment may document progressive cardiac remodelling. In the field of congenital heart disease, assessment of RV function is of particular interest in patients with abnormal pressure or volume loads on the ventricle, disproportion between the left and right ventricles, or cardiomyopathy. Abnormal pressure load may arise from RV outflow tract obstruction, ventriculo-arterial discordance with a systemic right ventricle or in the RV dominant single ventricle circulation. Abnormal volume load may arise due to intracardiac shunts, gross pulmonary incompetence or in a biatrial connection to a single ventricle. Primary RV dysfunction, such as may occur in arrhythmogenic right ventricular cardiomyopathy (ARVC)1 or secondary RV dysfunction due to pulmonary hypertension, will also require an assessment of shape, function and haemodynamics.2 The right ventricle may be imaged with standard one and two dimensional (2D) techniques (M mode and 2D echocardiography,3 4 radionuclide angiocardiography and x ray angiography). More recently three dimensional (3D) techniques, such as 3D echocardiography,3 magnetic resonance imaging (MRI)3 5 6 (fig 1) and multidetector computed tomography (MDCT) may allow a more precise quantitative assessment of RV shape, volume and function. Tissue Doppler imaging (TDI) (fig 2) techniques may have a role in the non-invasive assessment of both global and regional function.7–9 The role of MRI myocardial tissue tagging (fig 3) and echocardiographic speckle tracking is currently under investigation as an RV functional assessment tool.7–9 Figure 1 The right ventricle (RV) is imaged with a free-breathing vector electrocardiogram (VCG) triggered steady state free precession (SSFP) technique with a T2 preparation prepulse (A, B and C). The intracardiac blood pool and the papillary muscles of the right ventricle are covered by a simplex mesh model (B). Subtraction of the papillary muscles from the volume of the simplex mash model is accomplished by choosing a threshold (C). This technique allows a three dimensional (3D) appreciation of the RV form and ejection fraction after analysis of end systolic and end diastolic 3D datasets with low of intra- and interobserver variability.5 Figure 2 Pulse wave tissue Doppler imaging (TDI) applied to the tricuspid annulus in a normal subject. A, late diastolic velocity; E, early diastolic velocity; S, systolic velocity. Figure 3 Myocardial tagging is displayed on different short axis views (A and B). It allows assessment of circumferential strain (C), radial shortening (D) and rotation of the right ventricle (E). The use of these values for assessment of the right ventricle is currently under investigation. Figure courtesy of H Stern, A Ruetz and R Luechinger. By imaging the right ventricle the following …