Mitral Valve Prolapse (MVP)

A 28 year old female presents with intermittent palpitations, atypical chest pain, and episodes of anxiety for several months. Symptoms worsen during emotional stress. Physical examination reveals a mid-systolic click followed by a late systolic murmur heard best at the apex. The murmur becomes louder with standing and softer with squatting. Diagnosis?

Diagnosis is mitral valve prolapse (MVP).

1. Definition

Mitral valve prolapse is a valvular disorder characterized by systolic displacement of one or both mitral valve leaflets into the left atrium during ventricular systole. It is most commonly caused by myxomatous degeneration and may occur with or without associated mitral regurgitation.

2. Etiology

2.1 Primary Causes

1. Myxomatous degeneration of mitral valve leaflets (most common)
2. Idiopathic leaflet thickening

2.2 Secondary Causes

1. Connective tissue disorders:
• Marfan syndrome
• Ehlers-Danlos syndrome
2. Chordae tendineae abnormalities
3. Papillary muscle dysfunction
4. Familial mitral valve prolapse

3. Pathophysiology

1. Degeneration and redundancy of mitral valve leaflets
2. Systolic displacement of leaflet(s) into the left atrium
3. Incomplete leaflet coaptation may lead to mitral regurgitation
4. Chronic significant mitral regurgitation may cause left atrial enlargement and arrhythmias

4. Clinical Features

4.1 Symptoms

1. Palpitations
2. Atypical chest pain
3. Anxiety
4. Fatigue
5. Dizziness
6. Dyspnea in patients with significant mitral regurgitation

4.2 Physical Examination

Classic Auscultation Findings

1. Mid-systolic click is the classic finding
2. Late systolic murmur occurs only if associated mitral regurgitation is present
3. Murmur is best heard at the apex

Dynamic Maneuvers

Click Occurs Earlier and Murmur Becomes Longer/Louder With

1. Standing
2. Valsalva maneuver

These decrease left ventricular volume causing earlier leaflet prolapse

Click Occurs Later and Murmur Becomes Shorter/Softer With

1. Squatting
2. Passive leg raise

These increase left ventricular volume delaying prolapse

Handgrip Maneuver

1. Increases afterload
2. May increase associated mitral regurgitation
3. Can delay the click and shorten the MVP murmur

5. Diagnosis

5.1 Electrocardiogram

1. Usually normal
2. May show nonspecific ST-T changes
3. Occasional atrial or ventricular arrhythmias

5.2 Echocardiography (Gold Standard)

Diagnostic criteria:

1. Superior displacement of mitral leaflet(s) ≥2 mm beyond the mitral annular plane into the left atrium during systole (classically assessed in parasternal long-axis view)
2. Assess severity of associated mitral regurgitation
3. Evaluate left ventricular and left atrial size
4. Assess ejection fraction

Uncomplicated MVP often demonstrates normal EF and normal chamber morphology

6. Complications

1. Mitral regurgitation
2. Atrial fibrillation
3. Ventricular arrhythmias
4. Chordae tendineae rupture
5. Heart failure in severe regurgitation
6. Rarely infective endocarditis

7. Differential Diagnosis

1. Mitral regurgitation
2. Hypertrophic cardiomyopathy
3. Tricuspid valve prolapse
4. Anxiety disorder
5. Coronary artery disease

8. Management

8.1 Observation

1. Most asymptomatic patients require reassurance and routine follow-up only

8.2 Lifestyle Measures

1. Regular exercise is generally encouraged
2. Adequate sleep hygiene
3. Reduce excessive caffeine intake
4. Limit alcohol intake
5. Stress reduction

Exercise restriction is generally unnecessary unless significant mitral regurgitation, arrhythmias, or ventricular dysfunction develops

8.3 Medical Therapy

Beta Blockers

1. Propranolol or other beta blockers for:
• Palpitations
• Chest discomfort
• Associated autonomic symptoms

8.4 Significant Mitral Regurgitation

1. Serial echocardiographic follow-up
2. Surgical mitral valve repair is preferred for severe symptomatic regurgitation

Routine antibiotic prophylaxis for infective endocarditis is not recommended

9. Prognosis

1. Most patients have a benign course
2. Prognosis is excellent without significant mitral regurgitation
3. Severe mitral regurgitation may require intervention

10. Key Clinical Insight

Young patient with palpitations, atypical chest pain, and a mid-systolic click that becomes earlier with standing strongly suggests mitral valve prolapse

11. Key Exam Points

1. Most commonly caused by myxomatous degeneration
2. Mid-systolic click is the classic auscultatory finding
3. Standing and Valsalva produce earlier click and longer murmur
4. Squatting and passive leg raise delay the click and soften the murmur
5. Echocardiography is the diagnostic test of choice
6. Late systolic murmur occurs only with associated mitral regurgitation
7. Beta blockers improve symptomatic palpitations and chest discomfort
8. Routine infective endocarditis prophylaxis is not recommended
9. Most patients require reassurance rather than intervention
10. Severe mitral regurgitation is the major clinically important complication