Mitral leaflet separation index

Last revised by Joshua Yap on 21 Jul 2023

The mitral leaflet separation (MLS) index is a semi-quantitative and complementary approach for assessing the degree of mitral stenosis by using two-dimensional echocardiography. It strongly correlates with the mitral valve area using planimetry and pressure half-time techniques 1-3.


It is calculated by measuring the distance between the tips of the mitral leaflets from their inner edges in end-diastole in both the parasternal long axis and apical four-chamber views and averaging the two 1-4.

History and etymology

The mitral leaflet separation index was first described by American cardiologist Michael L Fisher and his colleagues in 1979 as a measure of mitral stenosis severity 4.

ADVERTISEMENT: Supporters see fewer/no ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.