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 4-6cm. 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.

Cross section of the heart valves

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 TEE has additional value in assessing the anatomy and function.

Scallop partition of mitral valve

Regurgitation

Quantification of mitral valve regurgitation

ParameterMildModerateSevere
Jet Area/LA (%)<2020-40>40
Jet Area (cm²)<44-10>10
ERO (mm²)<2020-40>40
Vena contracta (mm)<33-7>7

Echocardiographic criteria for the definition of severe mitral valve regurgitation: an integrative approuch

ParameterCriteria
Qualitative
Valve morphologyFlail leaflet/ruptured pappilairy muscle/large coaptation defect
Colour flow regurgitant jetVery large central jet or eccentric jet adhering, swirling and reaching the posterior wall of the LA
CW signal of regurgitant jetDense/triangular
OtherLarge flow convergence zone *
Semiquantitative
Vena contracta width (mm)≥7 (>8 for biplane) **
Upstream vein flowSystolic pulmonary vein flow reversal
InflowE-wave dominant ≥1.5 m/s ***
OtherTVI mitral/TVI aortic >1.4
QuantativePrimarySecundary ****
EROA (mm²)≥40≥20
Regugitant volume (mL/beat)≥60≥30
Enlargement of cardiac chamber/vesselsLV, 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 dilationDegeneracyAcquired valve deviationSecundary
AtriumfibrillationMalcaptation in mitral valve stenosisBillowingRhythm disorders (LBBB-->diastolic MR)
LV dilationProlapsSAM in HCM
LA dilationFloppy valve
Flail leaflet
Chordal rupture
Ruptured Papillary muscle

Ruptured mitral chordae tendineae assessed with 3D TEE

Eur J Echocardiogr. 2010 May;11(4):307-32

European Heart Journal (2017) 00, 1?53

Stenosis

Quantification of mitral stenosis

ParameterMildModerateSevere
MVA (cm²)> 1.51.5 - 1.0< 1.0
PGmean (mmHg)< 55 - 10> 10
PHT (m/s)< 9090 - 150> 150

Causes of mitral stenosis

AcquiredTumorCongenital
DegeneracyMyxomaParachute valve
Rheumatic feverCor triatriatum sinistrum

J Am Soc Echocardiogr. 2009 Jan;22(1):1-23; quiz 101-2

European Heart Journal (2017) 00, 1?53