How to Differentiate Mitral Regurgitation (MR) vs Aortic Stenosis (AS) on CW Doppler and CW envelope SHAPE

 

How to Differentiate Mitral Regurgitation (MR) vs Aortic Stenosis (AS) on CW Doppler and CW envelope SHAPE

1. Timing

MR

Holosystolic signal (throughout systole).

Starts with isovolumic contraction and ends after A2 sometimes.

No clear envelope edges.

AS

Mid-systolic envelope (starts after IVCT, ends before A2).

Well-defined start and end.

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2. Shape of CW Envelope

Mitral Regurgitation (MR)

Tall, dense, triangular (early-peaking)

“V-shaped” or triangular because MR is often pressure-dependent.

Peak velocity early then falls → early systolic peak (unless severe chronic MR → rounded).

Aortic Stenosis (AS)

Parabolic, rounded, symmetric envelope

“Bullet shape”

Peaks mid-systole (late peak if severe).

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3. Velocity

MR usually has higher velocity (5–6 m/s common).

AS varies depending on severity but usually 3–5 m/s.

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4. Direction & Position of CW Line

MR CW is obtained from the apex directed posteriorly into the LA.

AS CW is obtained in multiple windows (RUP parasternal, apical, suprasternal).

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Summary

MR

Holosystolic

Triangular / V-shaped

Early peak

Very high velocity

Fills entire systole

AS

Mid-systolic

Rounded / parabolic

Mid or late peak

Duration shorter

Does not start at MVC and ends before A2