Mitral Valve Prolapse: Causes, Pathophysiology, Symptoms, Diagnosis, Management and Prevention

Mitral Valve Prolapse: Causes, Pathophysiology, Symptoms, Diagnosis and Management

~Introduction

Mitral Valve Prolapse (MVP) is one of the most common valvular heart disorders, affecting approximately 2–3% of the general population. It is characterized by the abnormal displacement or “billowing” of one or both leaflets of the mitral valve into the left atrium during systole (heart contraction). While many individuals with MVP remain asymptomatic and live normal lives, some may develop complications such as mitral regurgitation, infective endocarditis, arrhythmias, or, rarely, sudden cardiac death.

Understanding MVP involves a careful look into cardiac anatomy, etiology, pathophysiology, clinical manifestations, diagnostic approaches, and treatment options. This article provides a comprehensive overview of the condition for medical students, healthcare professionals, and those interested in cardiovascular health.

~Anatomy and Function of the Mitral Valve

The mitral valve, also known as the bicuspid valve, lies between the left atrium and left ventricle of the heart. It consists of two leaflets — anterior and posterior — that open during diastole to allow blood to flow from the left atrium into the left ventricle and close during systole to prevent backflow.

The valve is supported by:

• Chordae tendineae, which attach the valve leaflets to the papillary muscles.

• Papillary muscles, which anchor the chordae to the left ventricular wall.

• Annulus, a fibrous ring that maintains the structural integrity of the valve.

Proper coordination among these components ensures unidirectional blood flow. In MVP, structural or functional abnormalities cause one or both valve leaflets to bulge backward into the left atrium during systole.

~Definition and Pathophysiology

Mitral Valve Prolapse occurs when one or both mitral valve leaflets billow more than 2 mm above the mitral annular plane during systole, as seen on echocardiography. The leaflet tissue may be thickened or redundant, often described as “myxomatous degeneration.”

Pathophysiological Mechanisms

1. Myxomatous Degeneration:

   • The most common underlying mechanism.

   • The collagen and elastin fibers within the valve leaflets are replaced with mucoid (gelatinous) material, leading to leaflet thickening and elongation.

2. Chordae Tendineae Elongation or Rupture:

   • The elongated or ruptured chordae fail to maintain leaflet tension, allowing prolapse into the atrium.

3. Annular Dilation:

   • Enlargement of the mitral annulus (often secondary to left ventricular dilation) can contribute to prolapse and regurgitation.

4. Autonomic Dysfunction:

   • Some patients with MVP experience autonomic imbalances leading to palpitations, chest discomfort, or anxiety.

~Causes and Risk Factors

MVP can be primary (idiopathic or inherited) or secondary to other conditions.

1. Primary Mitral Valve Prolapse

This type is associated with intrinsic abnormalities of the valve tissue.

• Genetic factors: MVP often shows autosomal dominant inheritance with variable expression.

• Connective tissue disorders:

  • Marfan Syndrome

  • Ehlers–Danlos Syndrome

  • Osteogenesis Imperfecta

  • Pseudoxanthoma Elasticum

• Familial MVP: Linked to mutations in fibrillin-1 or other connective tissue genes.

2. Secondary (Functional) MVP

This type occurs as a consequence of other cardiac or systemic conditions:

• Ischemic heart disease causing papillary muscle dysfunction.

• Rheumatic heart disease leading to scarring and deformity.

• Hypertrophic cardiomyopathy altering ventricular geometry.

• Dilated cardiomyopathy causing annular dilation.

3. Risk Factors

• Female gender (more common in young women)

• Family history of MVP

• Thin body habitus

• Presence of scoliosis or pectus excavatum

• Autonomic dysfunction syndromes (e.g., postural orthostatic tachycardia syndrome)

~Clinical Features

MVP manifests with a wide spectrum of symptoms — from completely asymptomatic cases to those with significant hemodynamic compromise due to mitral regurgitation.

1. Asymptomatic Individuals

Most people with MVP are discovered incidentally during a routine physical exam or echocardiogram.

2. Symptomatic Presentation

Symptoms may be due to autonomic dysfunction or due to significant mitral regurgitation.

Common Symptoms:

• Palpitations: Due to premature ventricular contractions or supraventricular arrhythmias.

• Chest pain: Typically atypical, sharp, and non-exertional.

• Fatigue and exercise intolerance.

• Dyspnea on exertion: Due to mitral regurgitation.

• Dizziness or syncope: Occasionally due to arrhythmias or autonomic dysfunction.

• Anxiety and panic attacks: Common in some MVP patients, possibly related to autonomic imbalance.

~Physical Examination Findings

The hallmark physical finding in MVP is a mid-systolic click heard best at the cardiac apex. This click is due to the sudden tensing of the prolapsing valve leaflets or chordae.

Classic Auscultatory Findings:

1. Mid-systolic click — most prominent when the patient is standing or during Valsalva maneuver (reduces venous return).

2. Late systolic murmur — due to mitral regurgitation, which may extend up to the second heart sound.

Maneuvers and Effects:

• Standing or Valsalva: click occurs earlier, murmur lengthens.

• Squatting or handgrip: click occurs later, murmur shortens.

~Complications of MVP

Although usually benign, MVP can lead to serious complications in some cases:

1. Mitral Regurgitation (MR):

   • The most common complication.

   • Chronic MR can lead to left atrial and ventricular enlargement, atrial fibrillation, and heart failure.

2. Infective Endocarditis:

   • Damaged or thickened valve tissue provides a nidus for bacterial colonization.

3. Arrhythmias:

   • Both atrial and ventricular arrhythmias can occur, sometimes leading to palpitations or syncope.

4. Cerebral or Systemic Emboli:

   • Thrombus formation due to atrial fibrillation or platelet aggregation on abnormal valve tissue.

5. Sudden Cardiac Death (rare):

   • May result from malignant ventricular arrhythmias in severe cases.

~Diagnosis

Diagnosis is primarily established through clinical examination and echocardiographic evaluation.

1. Echocardiography (Gold Standard)

• Confirms the diagnosis and assesses the severity of prolapse and regurgitation.

• M-mode and 2D Echo Findings:

  • Leaflet displacement >2 mm above the annular plane during systole.

  • Thickened, redundant leaflets.

  • Presence and severity of mitral regurgitation.

2. Doppler Studies

• Evaluate direction and velocity of regurgitant jet.

• Quantify regurgitation severity.

3. Electrocardiogram (ECG)

• May be normal or show nonspecific ST-T wave abnormalities.

• Occasional premature ventricular contractions or supraventricular arrhythmias.

4. Chest X-ray

• Normal in mild cases.

• In severe MR: may show left atrial or ventricular enlargement and pulmonary congestion.

5. Holter Monitoring

• Detects arrhythmias and correlates them with symptoms such as palpitations or dizziness.

6. Cardiac MRI

• Used for detailed morphological and functional assessment in complex or uncertain cases.

~Management of Mitral Valve Prolapse

Management depends on the severity of prolapse, presence of symptoms, and degree of mitral regurgitation.

1. Asymptomatic Patients

• No specific therapy required if there is no or mild regurgitation.

• Regular follow-up with echocardiography every 3–5 years.

• Lifestyle modifications:

  • Avoid caffeine, tobacco, and stimulants.

  • Maintain hydration and adequate salt intake if prone to dizziness.

  • Regular aerobic exercise unless contraindicated.

2. Symptomatic Patients Without Significant MR

• Beta-blockers (e.g., propranolol, metoprolol): for palpitations, chest discomfort, or anxiety.

• Lifestyle management of autonomic symptoms.

• Avoidance of dehydration and excessive alcohol.

3. Patients with Significant Mitral Regurgitation

• Medical therapy:

  • Vasodilators (ACE inhibitors) if left ventricular dysfunction is present.

  • Diuretics for heart failure symptoms.

  • Anticoagulation if atrial fibrillation develops.

• Surgical management:

  • Mitral valve repair (preferred) — preserves native valve and ventricular function.

  • Mitral valve replacement — if repair is not feasible.

Indications for Surgery:

• Severe MR with symptoms.

• Left ventricular systolic dysfunction (EF < 60%).

• Progressive left ventricular dilation.

• New-onset atrial fibrillation or pulmonary hypertension.

4. Prevention of Infective Endocarditis

• Prophylactic antibiotics are not routinely recommended for all MVP patients.

• Indicated only for those with prior endocarditis or prosthetic valves before high-risk dental or surgical procedures.

~Prognosis

The overall prognosis of Mitral Valve Prolapse is excellent for most patients. The majority remain asymptomatic with a normal life expectancy.

Prognostic Factors:

• Good prognosis: Thin leaflets, no MR, normal LV function.

• Poor prognosis: Severe MR, flail leaflet, left atrial enlargement, or reduced ejection fraction.

Patients with severe MR who undergo timely surgical repair generally have outcomes similar to the normal population.

~Recent Advances and Research

1. Genetic Studies: Ongoing research aims to identify specific genes responsible for familial and connective tissue-related MVP.

2. 3D Echocardiography: Offers enhanced visualization of valve morphology and function, improving surgical planning.

3. Percutaneous Mitral Valve Repair: Minimally invasive techniques, such as the MitraClip, have revolutionized treatment for patients at high surgical risk.

4. Artificial Intelligence in Echocardiography: AI-based algorithms can detect subtle changes in valve motion earlier than traditional methods.

~Prevention and Lifestyle Considerations

While MVP cannot always be prevented, its progression and complications can be minimized through:

• Regular medical check-ups.

• Maintaining optimal body weight.

• Controlling blood pressure.

• Avoiding stimulants (caffeine, nicotine).

• Engaging in moderate physical activity.

• Managing anxiety and stress through relaxation techniques.

~Conclusion

Mitral Valve Prolapse is a common but often benign valvular disorder characterized by the displacement of mitral leaflets into the left atrium during systole. While most individuals remain asymptomatic, a subset may develop mitral regurgitation and other complications requiring medical or surgical intervention. Advances in imaging, genetics, and minimally invasive repair techniques have greatly improved diagnosis, management, and prognosis.

With appropriate follow-up and lifestyle measures, individuals with MVP can lead long, healthy, and active lives.