Assessment of RV Function

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Assessing RV wall thickness helps determine the chronicity of right heart strain. It is best measured in diastole using the PLAX view.

• Normal: < 5 mm
• Abnormal: > 5 mm, suggestive of chronic pressure overload (e.g., pulmonary HTN, COPD)
• Note: Normal wall thickness with RV dilation may indicate an acute process (e.g., PE) 

The Rule of Thirds is a quick, qualitative tool used in the PLAX view to assess for RV enlargement. In a normal heart during diastole, the RV, LA, and LVOT should each occupy about 1/3 of the screen.

• Normal: LA, LVOT, and RV each take up ~1/3 of the screen
• Abnormal: Disproportionately large RV suggests RV dilatation

RV dilatation is present when the RV appears equal to or larger than the LV, with an RV:LV ratio > 1:1. This is suggestive of RV strain from pressure or volume overload, and should prompt evaluation for underlying causes, such as a pulmonary embolism or chronic pulmonary disease.

How to Identify (A4C, PLAX):

In A4C or PLAX view, visualize both ventricles. Compare the RV to the LV in end-diastole.

• Normal: RV is ~2/3 the size of the LV. RV:LV ratio is < 1:1
• RV Dilatation: RV:LV ratio > 1:1

⚠️ Be cautious about proper image acquisition to avoid foreshortening or misrepresentation. 

This is an abnormal shift of the interventricular septum toward the LV that can be seen in multiple views (PSAX, PLAX, A4C). It is caused by elevated RV pressure pushing the septum leftward. 

• Systolic bowing: suggests pressure overload
• Diastolic bowing: suggests volume overload

The D sign is flattening of the septum in PSAX view, causing the LV to appear D-shaped. It occurs in systole with RV pressure overload (e.g., PE, pulmonary hypertension) or in diastole with RV volume overload.
 

How to Identify (PSAX, mid-papillary level):

In the PSAX view, focus on the interventricular septum and LV shape:

• Normal: LV appears round
• D Sign: Septal flattening results in the LV taking on a “D” shape 

McConnell’s sign is a pattern of RV wall motion abnormality associated with acute pulmonary embolism. It helps differentiate acute RV strain from chronic RV dysfunction, where RV hypokinesis is typically global.

How to Identify (A4C View): 

In the A4C view, focus on the RV free wall motion to identify this pattern.

• Mid-RV free wall: Akinesia or hypokinesis
• RV apex: Preserved contractility

⚠️ McConnell’s sign is not specific and may be seen in other conditions. Always interpret in clinical context.

TAPSE is an M-mode measurement obtained via A4C that estimates RV systolic function. It measures the lateral tricuspid annulus movement towards the RV apex during systole. It is a surrogate for RV longitudinal (base to apex) contraction, the dominant motion of the RV. 

How to Obtain TAPSE:

1. Obtain an A4C view and activate M-mode
2. Place the cursor over the lateral tricuspid annulus
3. Freeze and measure peak-to-trough vertical excursion of the annulus during systole

Interpretation:

• TAPSE > 17 mm: Normal RV function
• TAPSE < 17 mm: Suggests RV systolic dysfunction (e.g., PE, pulmonary HTN, or RV failure)

⚠️ TAPSE is angle- and image-dependent, and may appear falsely normal in regional RV dysfunction (e.g., McConnell’s sign).