Mitral Valve

Anatomy

The mitral valve consists of two valve leaflets, the anterior leaflet (AMVL) and the posterior leaflet (PMVL), which together have a surface of 4 - 6 cm². Via chordae tendineae, small tendons which ensure that the leaflets do not prolapse, the valve leaflets are attached to two major papillary muscles (anterolateral en posteromedial) in the left ventricle.

Top view of the normal heart showing the coronary arteries and four valves including the mitral valve with its anterior (A) and posterior (P) leaflets[1]

The mitral valve is bringing many scan faces in pictures: PLAX, PSAXmv, AP4Ch, AP5Ch, AP2Ch, AP3Ch and subcostal4Ch. Mitral valvular insufficiency should be considered in all views. When significant abnormalities of the mitral valve are suspected, TEE (particularly 3D TEE) can assist in assessing the severity.

Video
3D (TEE) view of MV with a chorda rupture

 

Examples of Mitral variants (AP4Ch)
Video	Video
Normal	Degenerative
Video	Video
Prolapse	Rheumatic

 

The scallops of the mitral valve

The two leaflets are divided into a total of six scallops: A1, A2, A3 (anterior) and P1, P2, P3 (posterior).

MV AP2CH	MV PSAX	MV Surgical view
MV AP4CH	MV PLAX	MV TEE views (Fig. click for animation)
Source image: Mechanisms of Mitral regugitation - role of 3D ultrasound illustrated by case studies - ML Geleijnse.[2]

Stenosis

Causes of mitral valve stenosis
Acquired	Degeneracy Rheumatic fever
Space occupying lesion	Myxoma
Congenital	Parachute valve Cor triatriatum

Effects of mitral valve stenosis:

Chest pain, of breath when lying flat, with exertion and attacks during the night or morning (cardiac asthma), possibly coughing up blood; any complaints from right valve failure, such as ankle edema. Palpitations by atrial fibrillation, which can cause embolism, such as a stroke.

Treatment

The valve can be opened by balloon angioplasty or surgically treated by valve replacement.

Click here for mitral stenosis quantification.

Insufficiency

Causes of mitral valvular insufficiency
Annular dilatation	Atrial fibrillation Left ventricular dilatation Left atrial dilatation
Degenerative disease	Malcoaptation at mitral valve stenosis
Acquired valve defect	Billowing Prolapse Floppy valve Flail Chordal rupture Papillary muscle rupture
Secondary	Arrhythmias (LBBB-->diastolic MI) SAM in HCM

Mitral valve insufficiency (MI) may result in left-sided congestive heart failure. An MI results in back flow of blood from the left ventricle into the left atrium. This may eventually result in pulmonary hypertension and pulmonary edema. Pulmonary edema is manifested by shortness of breath, initially with exertion, but later at rest, orthopnea and nocturnal dyspnea attacks. On physical examination, pulmonary edema can be detected by fine crackles, particularly in the dorsobasale lung fields. Increasing left atrial pressure and dimension may cause atrial fibrillation.

Click here for quantification mitral valvular insufficiency .

References

1. How the heart works from Geisinger’s Health Library.

2. Mechanisms of Mitral regugitation - ML Geleijnse.