Mitral valve

 

 

Anatomy

The mitral valve consists of two leaflets, the anterior (A) and the posterior valve leaflet (P), which together have a surface area of 4-6cm². At the inner edges of the leaflets chordae tendinae are attached, which ensure that the leaflets did not prolapse back into the atria during systole. The chordae attach to two large papillary muscles, that are part of the muscular tissue of the left ventricle.

The mitral valve can be visualized in many views: PLAX, PSAXmv, AP4Ch, AP5Ch, AP2Ch, AP3Ch and subcostaal4Ch. A prolapse of the MV is best assessed on PLAX. However, mitral regurgitation should be assessed in all views. In case of major abnormalities of the mitral valve 3D TOE has additional value in assessing the anatomy and function.

 

Ruptured mitral chordae tendineae assessed with 3D TOE

 

MV scallop partition
MVscallops

 

Regurgitation

 

 

Quantification of mitral valve regurgitation
Parameter Mild Moderate Severe
Jet Area/LA (%) <20 20-40 >40
Jet Area (cm²) <4 4-10 >10
ERO (mm²) <20 20-40 >40
Vena contracta (mm) <3 3-7 >7

 

 

Echocardiographic criteria for the definition of severe mitral valve regurgitation: an integrative approuch
Qualitative
Valve morphology Flail leaflet/ruptured pappilairy muscle/large coaptation defect
Colour flow regurgitant jet Very large central jet or eccentric jet adhering, swirling and reaching the posterior wall of the LA
CW signal of regurgitant jet Dense/triangular
Other Large flow convergence zone *
Semiquantitative
Vena contracta width (mm) ≥7 (>8 for biplane) **
Upstream vein flow Systolic pulmonary vein flow reversal
Inflow E-wave dominant ≥1.5 m/s ***
Other TVI mitral/TVI aortic >1.4
Quantative Primary Secundary ****
EROA (mm²) ≥40 ≥20
Regugitant volume (mL/beat) ≥60 ≥30
Enlargement of cardiac chamber/vessels LV, LA  

* At Nyquist limit of 50-60 cm/s.

** For average between AP4Ch an AP2Ch.

*** In the absence of other causes of elevated LA pressure and of mitral stenosis.

**** Different thresholds are used in secondary mitral regurgitation where an EROA >20mm² and regurgitant volume > 30mL identify a subset of patients at increased risk of cardiac events.

 

Severe MR because of prolaps

 

 

Causes of mitral valve regurgitation
Annulus dilation Degeneracy Acquired valve deviation Secundary
Atriumfibrillation Malcaptation in mitral valve stenosis Billowing Rhythm disorders (LBTB-->diastolic MR)
Leftventricle dilation Prolaps SAM in HCM
Leftatrium dilation Floppy valve
Flail
Chordal rupture
Ruptured Papillary muscle

 

Stenosis

 

 

Quantification of mitral stenosis
Parameter Mild Moderate Severe
MVA (cm²) >1.5 1.5-1.0 <1.0
PGmean (mmHg) <5 5-10 >10
PHT (m/s) <90 90-150 >150

 

 

Causes of mitral stenosis
Acquired Tumor Congenital
Degeneracy Myxoma Parachute valve
Rheumatic fever Cor triatriatum sinistrum

 

Severe MS because of degeneracy

 

Pane D

Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas.