Mitral Valve Prolapse (MVP): The Click Behind the Murmur
Introduction
Mitral Valve Prolapse (MVP) is one of the most common valvular heart abnormalities encountered in clinical practice. It occurs when one or both mitral valve leaflets bulge backward into the left atrium during systole. While many patients remain asymptomatic throughout life, others may develop palpitations, arrhythmias, mitral regurgitation, or rarely sudden cardiac death.
With advancements in echocardiography, our understanding of MVP has evolved from a benign auscultatory curiosity to a clinically important structural heart disease with distinct phenotypes and risk profiles.
---
Anatomy of the Mitral Valve
The mitral valve apparatus consists of:
Anterior and posterior mitral leaflets
Mitral annulus
Chordae tendineae
Papillary muscles
Left ventricular myocardium
Proper coaptation of these structures ensures unidirectional blood flow from the left atrium to the left ventricle.
In MVP, leaflet redundancy, myxomatous degeneration, or chordal elongation leads to systolic displacement of the valve into the left atrium.
---
Definition of Mitral Valve Prolapse
Echocardiographically, MVP is defined as:
> Systolic displacement of one or both mitral valve leaflets ≥2 mm above the mitral annular plane into the left atrium in the parasternal long-axis view.
Two major forms are recognized:
Classic MVP
Leaflet thickness ≥5 mm
Marked myxomatous degeneration
Higher risk of complications
Non-classic MVP
Leaflet thickness <5 mm
Usually milder disease
---
Pathophysiology
The underlying mechanism commonly involves:
Myxomatous degeneration of leaflets
Excess leaflet tissue
Elongated or ruptured chordae tendineae
Annular dilatation
These changes produce leaflet billowing and incomplete closure during systole, potentially causing mitral regurgitation.
Over time, chronic volume overload may lead to:
Left atrial enlargement
Left ventricular dilatation
Atrial fibrillation
Pulmonary hypertension
Heart failure
---
Etiology and Associations
MVP may occur:
Primary (Degenerative)
Myxomatous degeneration
Fibroelastic deficiency
Secondary Associations
Marfan syndrome
Ehlers-Danlos syndrome
Osteogenesis imperfecta
Hypertrophic cardiomyopathy
Rheumatic involvement
Familial clustering is recognized in some patients.
---
Clinical Presentation
Many patients are asymptomatic and diagnosed incidentally.
Common Symptoms
Palpitations
Atypical chest pain
Fatigue
Dyspnea
Dizziness
Anxiety-like symptoms
Physical Examination
Classic auscultatory findings include:
Mid-systolic click
Late systolic murmur
The click results from sudden tensing of redundant leaflets and chordae.
Maneuvers that reduce LV volume (e.g., standing, Valsalva) make the click occur earlier.
---
Echocardiographic Evaluation
Echocardiography is the cornerstone for diagnosis and risk assessment.
Key Echo Findings
Leaflet prolapse into left atrium
Leaflet thickening or redundancy
Mitral regurgitation severity
Chordal rupture or flail leaflet
Left atrial and LV size
Annular disjunction
Important Views
Parasternal long-axis
Apical 4-chamber
Apical long-axis
3D echocardiography further improves anatomical characterization.
---
Mitral Annular Disjunction (MAD)
Mitral annular disjunction refers to separation between the mitral annulus and ventricular myocardium.
MAD has gained attention because of its association with:
Ventricular arrhythmias
Fibrosis
Sudden cardiac death in selected patients
Recognition of arrhythmic MVP is increasingly important in modern cardiology.
---
Arrhythmic MVP
A small subset of patients develop malignant ventricular arrhythmias.
High-Risk Features
Bileaflet prolapse
Mitral annular disjunction
Inferior T-wave inversion
Frequent PVCs
Complex ventricular ectopy
Papillary muscle fibrosis on cardiac MRI
Severe myxomatous disease
Symptoms may include:
Syncope
Presyncope
Sustained ventricular tachycardia
Holter monitoring and cardiac MRI may help risk stratification.
---
Complications
Potential complications include:
Mitral regurgitation
Chordal rupture
Infective endocarditis
Atrial fibrillation
Heart failure
Ventricular arrhythmias
Sudden cardiac death (rare)
Most patients, however, have an excellent prognosis.
---
Management
Treatment depends on symptoms and severity.
Asymptomatic Patients
Reassurance
Periodic echocardiographic follow-up
Symptomatic Patients
Beta blockers may help:
Palpitations
Anxiety symptoms
Hyperadrenergic states
Severe Mitral Regurgitation
Surgical repair is preferred when feasible.
Indications include:
Symptoms
LV dysfunction
LV dilatation
New atrial fibrillation
Pulmonary hypertension
Mitral valve repair generally provides excellent long-term outcomes.
---
Lifestyle and Prognosis
Most patients lead completely normal lives.
Recommendations include:
Regular follow-up
Blood pressure control
Exercise according to tolerance
Evaluation of unexplained syncope or arrhythmias
Routine antibiotic prophylaxis for endocarditis is no longer recommended solely for MVP.
---
Key Takeaways
MVP is a common valvular abnormality characterized by systolic leaflet displacement.
Echocardiography is essential for diagnosis and follow-up.
Most patients remain asymptomatic with excellent prognosis.
Severe MR and arrhythmic MVP represent important high-risk subsets.
Early recognition and timely intervention improve outcomes.
---
Conclusion
Mitral Valve Prolapse is far more than a simple midsystolic click. It represents a diverse spectrum ranging from benign incidental findings to advanced degenerative valve disease and arrhythmic syndromes. Modern imaging techniques have refined diagnosis, risk stratification, and treatment strategies.
Careful echocardiographic assessment, awareness of arrhythmic risk markers, and appropriate surveillance remain central to optimal patient care.
---
Comments
Post a Comment
Drop your thoughts here, we would love to hear from you