Chapter: The RV

RV Size RV Wall Thickness RV Function RA Pressure (E/e')

The Right Ventricle

An overview of right ventricular size and functional assessment

RIGHT VENTRICULAR SIZE

It may be harder to evaluate RV size than LV size. The RV is usually first seen in the PLAX view when part of the outflow tract is seen. The normal shape in this view is a bit triangular; seeing a rounded outflow tract is a hint of RV troubles. Measuring the “height” of the RV in this view is possible but not overly reliable and reference values are uncertain. The RV will also vary with patient height. Here is a PLAX image with a normal RV outflow tract shape.

Next is a PLAX clip from a patient with verified RV dilation.

The apical view is the standard for measuring the RV width. Both leaflets of the tricuspid valve need to be seen for a correct view of the RV. Measuring just the mid RV diameter is good enough in most clinical situations. Next is a clip of a dilated RV, although a common problem of an uncertain lateral RV wall was demonstrated.

To be sure about the RV lateral wall an RV enhanced apical4 view may be needed. A good subcostal view can also confirm RV dilation. Here is a slightly RV-enhanced apical4 that enabled a good measurement of the mid-RV diameter.

The RV free wall is usually measured in the subcostal view because the interface with the liver and the perpendicular orientation of the sound to the endocardium makes the wall clear. Here is an image from a patient with pulmonary hypertension who had hypertrophy of the free wall. A more precise measurement might have been obtained with a more optimized and magnified image.

It may be difficult to measure the RV free wall in livers with steatosis.

RV dimensions (cm)

Normal

Mild

Mod

Severe

Mid RV

2.7 - 3.3

3.4 - 3.7

3.8 - 4.1

≥ 4.2

RV free wall

0.1 - 0.6

 

 

 


RIGHT VENTRICULAR FUNCTION

An indicator of RV volume and pressure overload is flattening (D-ing) of the interventricular septum as an overloaded RV presses into the LV. This pattern may occur just during systole (usually pressure overload), throughout systole and diastole (usually volume and pressure overload), or briefly just with inspiration (classic pericardial tamponade pattern). The next clip shows PSAX septal flattening predominantly with systole and the flattening was accentuated during inspiration.

The following clip is an apical4 view from a patient with poor LV systolic function, but the increased RV pressure/volume shifted the septum into the LV with each beat.

RV function has a greater component of longitudinal contraction than LV function and this is most easily measured with tricuspid annular plane systolic excursion (TAPSE). Adjust the image to get the lateral tricuspid annulus excursion as parallel as possible to the M-mode cursor. This may require moving the annulus toward the center of the screen. Machines with anatomic M-mode will be able to get a more accurate measurement. As with MAPSE, find the difference between the peak and the valley. In the following case TAPSE was 2.6. Good TAPSE is usually easy to eyeball after enough training.

 

 

Normal

TAPSE (cm)

1.7 - 3.1

We had thought that having the M-mode cursor non-parallel to the tricuspid annulus would always result in an under measurement of TAPSE. However, we have anecdotally noticed that if the M-mode caliper passes through part of the tricuspid valve leaflets that you can get an over measurement of TAPSE. Thus, getting the annular movement as parallel to the M-mode cursor as possible is important for accuracy.