Aortic Regurgitation

There are many possible causes of AR, including:

Degenerative valve disease
Aortic root dilation (e.g. in connective tissue disorders like Marfan syndrome)
Rheumatic heart disease

Acute causes (more sudden onset) include:

Aortic dissection
Infective endocarditis
Iatrogenic causes (e.g. after valvular procedures)
On physical exam, AR presents as a blowing, decrescendo diastolic murmur, best heard at the left sternal border. There may be signs of wide pulse pressure, such as bounding pulses or head bobbing (De Musset's sign).

On POCUS, use colour doppler in the A5C view to look for a jet of blood flowing backward into the LV during diastole.

Steps for Image Acquisition:

Obtain an A5C: Start with an A4C, ensuring the septum is straight and centred. Transition into an A5C and visualize the LVOT and aortic valve.
Turn On Colour Doppler: Adjust the colour doppler box to encompass the entire LVOT and aortic valve.
Freeze and measure: In diastole, freeze the image when the regurgitant jet is most prominent. Use calipers to measure:
- Jet width
- LVOT diameter (within 1cm of aortic valve)

Interpretation:

Mild: Jet width < 25% of LVOT diameter
Moderate: Jet width 25–65% of LVOT diameter
Severe: Jet width > 65% of LVOT diameter

The video shown has no regurgitation.
Check out UBC's video of severe AR: https://www.ubcimpocus.com/new-gallery/2019/4/24/severe-ar-a4c