Mitral Valve Prolapse: Echocardiographic Assessment

Mitral valve prolapse (MVP) is systolic displacement of one or both mitral leaflets — anterior, posterior, or both — back toward the left atrium, beyond the plane of the mitral annulus. It is also known by several older names, reflecting decades of study: Barlow syndrome, floppy valve syndrome, systolic click–murmur syndrome, redundant cusp syndrome, and billowing mitral valve syndrome. It is one of the most common valve conditions, usually the leading cause of chronic primary mitral regurgitation in high-income countries, and most patients remain asymptomatic for life.

Types

• Mid-to-late systolic prolapse — leaflet displacement beginning partway through systole
• Holosystolic (pansystolic) prolapse — leaflet displacement present throughout systole

Etiology and Phenotypes

The exact cause is not fully understood, but MVP is associated with:

• Myxomatous degeneration — an unusually prominent spongiosa layer with loose myxoid material within the leaflet, generally associated with annular dilation
• A hereditary component
• Associated conditions — interatrial septal aneurysm, myocarditis, trauma, Ehlers-Danlos syndrome, systemic lupus erythematosus, and Wolff-Parkinson-White syndrome

Two distinct clinicopathologic phenotypes are recognized, and distinguishing them can matter for surgical planning:

• Barlow’s disease — typically younger patients, with severe myxomatous degeneration causing gross redundancy of both the anterior and posterior leaflets and the chordal apparatus. A subset of these patients go on to develop ventricular arrhythmias, mitral annular disjunction, and LV dilation (see below).
• Fibroelastic deficiency — typically older patients, where a lack of connective tissue integrity leads to more localized, often single-segment prolapse and chordal rupture, without the diffuse bileaflet redundancy seen in Barlow’s disease.

Signs and Symptoms

Most patients are asymptomatic and are identified incidentally. Symptomatic patients may report:

• Chest pain, usually atypical (not clearly exertional or classically anginal)
• Dyspnea
• Palpitations and arrhythmias
• Dizziness or syncope

Complications

• Progressive mitral regurgitation
• Infective endocarditis
• Embolic events — transient ischemic attack or stroke
• Ruptured chordae tendineae, leading to acute MR
• Arrhythmias
• Sudden cardiac death (rare, but see Arrhythmic MVP below)

Physical Appearance

Patients may have a normal or asthenic build, and abnormal thoracic features are recognized in association with MVP, including straight-back syndrome, scoliosis, and pectus excavatum or carinatum.

Cardiac Auscultation

• A mid-to-late systolic click, from sudden tensing of the chordae tendineae as the leaflet prolapses
• A systolic murmur, when significant mitral regurgitation accompanies the prolapse

Other Diagnostic Tools

• ECG — usually normal in asymptomatic patients. Findings, when present, may include inverted or biphasic T waves, non-specific ST-segment changes, or arrhythmias.
• Chest X-ray — usually normal; may show thoracic abnormalities such as scoliosis.

Echocardiographic Findings

M-Mode

• Thick, redundant leaflets — anterior and/or posterior leaflet thickness ≥5 mm measured at mid-diastole
• Mid-to-late systolic prolapse: leaflet sagging ≥2 mm from the C-D points
• Holosystolic prolapse: leaflet sagging ≥3 mm from the C-D points
• Abnormal LV posterior wall motion — a late systolic dip

2D Echocardiography

The parasternal long-axis view is the reference standard. Prolapse is present when any portion of the mitral leaflets extends beyond an imaginary line drawn between the posterior aortic root and the atrioventricular groove (the annular plane).

Key findings:

• A scalloped appearance of the mitral leaflets in the short-axis view
• Left atrial enlargement, when significant MR is present
• Left ventricular enlargement, from chronic volume overload
• Check for associated valve abnormalities — tricuspid, aortic, or pulmonic valve prolapse can co-occur

Doppler

Mitral regurgitation associated with MVP is typically late systolic, timed to when the leaflet crosses the annular plane; severe cases may show holosystolic MR instead. See the Mitral Regurgitation tutorial for how to grade any resulting regurgitation — the same primary-MR severity thresholds apply, since MVP is a primary (structural) cause of MR.

Arrhythmic MVP and Mitral Annular Disjunction

This is an area of substantial recent clinical attention, reflected in the current ESC/EACTS guideline. A subset of MVP patients — particularly those with Barlow’s disease — develop ventricular arrhythmias, and sudden cardiac death has been reported in individual cases. Critically, this arrhythmic risk is independent of MR severity: a patient with only mild or moderate regurgitation can still carry meaningful arrhythmic risk if other features are present.

The mechanism is thought to center on mitral annular disjunction (MAD) — atrial displacement of the posterior mitral leaflet’s hinge point away from the ventricular myocardium. This is believed to cause excessive mobility of the valvular apparatus and increased tension on the papillary muscles and posterobasal myocardium, leading to local fibrosis that can serve as an arrhythmic substrate.

Because of this, current guideline-informed echocardiographic assessment of MVP should explicitly evaluate for mitral annular disjunction as part of standard morphological assessment — alongside the traditional evaluation of leaflet thickness, mobility, and coaptation — rather than focusing on regurgitant severity alone.

Important Considerations

1. Diagnosis can be subjective. There is a wide spectrum between presumably normal valves and clearly prolapsed ones, and the boundary is not always sharp.
2. Leaflet redundancy raises risk. A grossly redundant-appearing valve carries a higher risk of the complications of MVP (classic, Barlow-type MVP) than a valve with milder, more focal displacement.
3. MVP is prevalent among young women, though it affects all demographics.
4. Tricuspid valve prolapse commonly co-occurs with MVP; check the tricuspid valve when MVP is identified.
5. Marfan syndrome is strongly associated with MVP — the connective tissue abnormality that affects the aorta in Marfan syndrome affects the mitral valve apparatus as well.
6. Provocative maneuvers — Valsalva or amyl nitrate, both of which reduce LV volume — can enhance MVP findings that are otherwise borderline, by accentuating the relative redundancy of the leaflets against a smaller ventricular cavity.
7. False positives can arise from a high transducer position, inferior angulation, or from secondary conditions such as a large pericardial effusion, primary pulmonary hypertension, or an atrial septal defect — all of which can distort the normal annular geometry or leaflet motion.
8. TEE criteria for MVP remain under refinement; the parasternal long-axis TTE view remains the primary reference standard described above, though TEE’s ME long-axis and mitral commissural views (see Transesophageal Echocardiography) are valuable for mapping which scallops are involved ahead of surgical repair.
9. A “cleft” mitral valve is not always what it appears. A true isolated cleft in an anterior mitral leaflet that is otherwise part of a normal, separate mitral annulus is a distinct and much rarer finding than the AV-valve commissure commonly (and somewhat imprecisely) called a “cleft” in Atrioventricular Septal Defect — the latter reflects a shared AV junction, not a defect within an otherwise normal mitral valve.

A note on sourcing: the specific frequency of co-existing tricuspid valve prolapse and the near-universal association of MVP with Marfan syndrome are well-established teaching points from the literature and standard references, but weren’t independently located as specific figures within the two guideline documents reviewed for this page.