Measuring the right ventricular outflow tract (RVOT) with echocardiography is a great way to recognize dilation of the right ventricle. Which views should you use for measurement? Which dimensions should you measure? How can you recognize right ventricular hypertrophy? In this video, Cristiana Monteiro – a cardiac physiologist from the University of Oxford – shares her expert approach to right-heart echo.
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We too often focus on the left ventricle and its pathologies when performing echo, forgetting that the right heart is also a significant source of symptoms and complications. It is an important prognostic predictor for many cardiac diseases. In this course, we’ll teach you the pearls and pitfalls of right-heart echocardiography so you can confidently assess the right heart and its pathologies. Master right-heart echocardiography and learn how to confidently assess the right heart and its pathologies with this course.
At the end of this Medmastery lesson, you will be able to measure the structures of the right ventricle using transthoracic echocardiography in a precise and reproducible way. Measuring the right ventricular outflow tract, or RVOT is one of the methods used to establish whether the right ventricle is dilated or normal in size. It is best done using the parasternal long axis view as seen here. This measurement can be obtained by starting at the hinge point between the aortic valve and the interventricular septum, and measuring vertically up towards the right ventricular endocardium.
Looking at the parasternal short axis view, we are now at the vessel level where the pulmonary and aortic valves are both visible. In this view, the right ventricular outflow tract is seen at the top of the screen and can be measured at two levels, proximal and distal levels. Both measurements help us understand if the right ventricle is dilated or normal in size.
When measuring the proximal RVOT, place the echo cursor just outside aorta at its center and within the RVOT. From here, draw a vertical line up to the right ventricular endocardium. The distal RVOT can be found just above the pulmonary valve and similarly, it can be measured by placing the echo cursor just outside the aorta, this time above the pulmonary valve at about two o'clock, stretching to the endocardium.
Now let's look at the apical view. The right ventricle in this view resembles a triangular wedge of cheese. Here we can take three measurements refered to as dimensions. Dimension one, the bass or basal diameter is taken just above the tricuspid valve annulus where the right ventricle is at its widest. Dimension two, the mid diameter is taken across the middle of the chamber just below the papillary muscles. Both of these measurements are taken from that interventricular septum to the right ventricular endocardium on the left of the screen.
Lastly, dimension three measures the length of the right ventricle from the middle of the tricuspid annulus to the apex. Recommendations and guidelines for how to use these measurements differ between countries and even continents. Be sure to find the guidelines for your region of practice, which should provide measurements to define a normal size or dilated right ventricle. The subcostal view is excellent for measuring the thickness of the ventricular muscle.
In order to obtain this measurement, zoom in and measure the thickness at the right ventricular wall. This measurement is helpful to understand if the right ventricle is hypertrophy, meaning the muscle is overgrown and this often happens in response to high pressures in the lungs and the right ventricle itself. Now that you know how to measure aspects of the right ventricle, be sure you always take these measurements in end diastole. This ensures you are measuring the ventricle at its largest dimension and it also guarantees consistency between scans and operators. Great job. You now know how to measure dimensions and the right ventricle.