Perhaps the most challenging anatomic structure to assess and one of the more consequential. The RV is a mind-bending 3 dimensional structure that requires careful visual assessment. The following section and video tutorial will guide you through this process.
As a practical rule, you can divide the left atrium, aorta, and right ventricular outflow tract by 1/3 in a well-acquired PLAX view. If an off-axis view is acquired, then this view is less accurate. While this view if less sensitive for RV dilatation (more sensitive for RVOT dilatation), it is very specific if the RV/RVOT segment is clearly enlarged.
As a quick rule, an RV size that is >2/3 size of the LV is enlarged. As a main caveat however, it must be a non-foreshortened LV (Apex can be seen). This view is the most challenging for novices to be acquired and is most likely to be confounded.
A normal inter-ventricular septum is convex twoards the RV with that convexity maintained as it shifts inward to the LV during systole.
In RV pressure overload you can see the septum at its maximal flatness in systole, but it can remain flattened during diastole. This is often referred to as a “D-shaped” septum.
In RV volume overload, the septum is at maximal flatness in diastole. It can be seen to “pop out” during systole as the pressure gradient in the LV easily overcomes that of the RV.
The predominant movement of the RV is longitudinal, that is from the base to the apex. Tricuspid annular systolic plane excursion (TAPSE) measures vertical displacement of the tricuspid annulus in systole. A normal vertical displacement is ~1.7 cm and greater. Notably, this is only one element of RV function and can easily be incorrect.
You can see in time time-motion M-mode recording that we are recording movement of the lateral annulus. Measurement should start at the trough and measure to the peak, but being sure you are measuring the same tissue plane.
RA dilatation is a helpful feature to recognize as it tells you that the RV problem, while may be at least partially acute, has a chronic element. RA dilatation requires at least >72 hours.
The most challenging aspect of managing a patient with RV dysfunction is the acute patient with obstructive shock. In this case, RV dilatation prevents diastolic filling of the LV. Although the LV may be hyper-dynamic, its diastolic filling may be exceptionally low. Management of this problem is exceptionally complex and requires a multi-disciplinary approach.
If the RV pressure is higher than the right sided filling pressure, you may see “spontaneous echo contrast” or “smoke” as a consequence of an unfavourable gradient for filling. In this condition, blood or occasionally infused saline microbubbles may swirl around the right sided circulation. This is more common in cardiac arrest and terminal PE/ severe pulmonary hypertension.
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