Case of the Month #31 Mitral stenosis and RV failure

Published 13/07/2022

How do you classify Mitral Stenosis (MS) and when is it usually symptomatic?

Mitral Stenosis is classified based on both the valve area and the peak pressure gradient across the valve. However, the pressure gradient can vary with the flow rate across the mitral valve, hence Mitral Valve Area is a more reliable indicator of severity.

Normal Mitral Valve Area is 4-6 cm2.


Valve area

Pressure Gradient

Mild MS


<5 mmHg

Moderate MS

1.0-1.5 cm2

6-10 mmHg

Severe MS

< 1 cm2

>10 mmHg


  • MS is usually symptomatic when the valve area is < 2.5 cm2.
  • Mild MS is symptomatic with exercise, fever, pregnancy and with atrial fibrillation.
  • Moderate MS is symptomatic at rest.