What are the characteristics and management of mitral valve prolapse?

Characteristics and Management of Mitral Valve Prolapse

Mitral valve prolapse (MVP) is characterized by abnormal systolic displacement of one or both mitral valve leaflets into the left atrium, defined echocardiographically as valve prolapse of 2 mm or more above the mitral annulus in the long-axis parasternal view, with leaflet thickness of 5 mm or more indicating abnormal leaflet redundancy. 1

Diagnostic Characteristics

Anatomical Features

• Displacement of mitral valve leaflets ≥2 mm above the mitral annulus during systole
• Leaflet coaptation occurring on the atrial side of the annular plane
• Leaflet thickness ≥5 mm indicates abnormal redundancy
• Often associated with enlarged mitral annulus and elongated chordae tendineae
• Pathologically characterized by myxomatous degeneration with marked proliferation of the spongiosa tissue 1

Auscultatory Findings

• Mid-systolic click(s) followed by a late systolic murmur
• Murmur may have musical or honking quality
• Dynamic auscultation shows characteristic changes:
  • Standing (decreased end-diastolic volume): click-murmur complex moves earlier in systole
  • Squatting (increased end-diastolic volume): click-murmur complex moves toward second heart sound
• Clicks may be intermittent and variable 1

Echocardiographic Findings

• Two-dimensional and Doppler echocardiography is the most useful diagnostic test
• Diagnostic criteria include:
  • Valve prolapse ≥2 mm above mitral annulus in long-axis parasternal view
  • Leaflet thickness ≥5 mm indicates abnormal thickness
  • Mitral regurgitation typically presents as high-velocity eccentric jet in late systole
  • Leaflet redundancy often associated with enlarged annulus and elongated chordae 1

Other Diagnostic Features

• ECG may be normal or show nonspecific ST-T wave changes, T-wave inversions, prominent Q waves, or QT prolongation
• Continuous ambulatory ECG recordings may document arrhythmias in symptomatic patients but are not indicated for routine testing in asymptomatic patients 1

Clinical Presentation

Common Symptoms

• Palpitations (often without documented arrhythmias)
• Atypical chest pain (rarely resembling classic angina)
• Dyspnea and fatigue
• Neuropsychiatric complaints (panic attacks, anxiety)
• Orthostatic symptoms due to postural hypotension and tachycardia 1

Prevalence

• Affects approximately 1-2.5% of the general population 1
• Most common valvular disease in the general population 2

Complications

Potential Complications

• Mitral regurgitation (progressive)
• Atrial fibrillation
• Congestive heart failure
• Endocarditis
• Ventricular arrhythmias
• Sudden cardiac death (rare but reported, especially in young athletes) 1, 3
• Cerebral ischemic episodes and stroke 1

Management Approach

Asymptomatic Patients

• Reassurance about benign prognosis for most patients
• Encourage normal lifestyle and regular exercise
• Regular follow-up with clinical evaluation and echocardiography 1

Symptomatic Patients

1. For palpitations and adrenergic symptoms:

   • Beta blockers for tachyarrhythmias and increased adrenergic symptoms
   • Cessation of stimulants (caffeine, alcohol, cigarettes)
   • Consider continuous or event-activated ambulatory ECG for recurrent palpitations 1

2. For orthostatic symptoms:

   • Volume expansion through liberal fluid and salt intake
   • Support stockings
   • Consider mineralocorticoid therapy or clonidine in severe cases 1

3. For patients with MVP and atrial fibrillation:

   • Warfarin therapy for patients >65 years or with hypertension, MR murmur, or history of heart failure
   • Aspirin therapy (75-325 mg/day) for patients <65 years without MR, hypertension, or heart failure 1

4. For patients with MVP and history of stroke:

   • Warfarin therapy for patients with MR, atrial fibrillation, or left atrial thrombus
   • Warfarin therapy is reasonable for patients with echocardiographic evidence of thickening (≥5 mm) or redundancy of valve leaflets without MR or atrial fibrillation
   • Aspirin therapy for patients without MR, atrial fibrillation, left atrial thrombus, or valve thickening/redundancy
   • Warfarin therapy for patients with transient ischemic attacks despite aspirin therapy 1

5. For high-risk MVP patients:

   • Consider aspirin therapy (75-325 mg/day) for patients in sinus rhythm with echocardiographic evidence of high-risk MVP 1

Special Considerations

Risk Stratification

• Higher risk features include:
  • Leaflet thickness ≥5 mm
  • Moderate to severe mitral regurgitation
  • Left ventricular dysfunction (EF ≤60%)
  • Left atrial enlargement
  • Flail leaflet 1

Monitoring

• Regular clinical follow-up for all patients
• Periodic echocardiographic assessment to monitor valve function and ventricular dimensions
• More frequent monitoring for patients with significant regurgitation or high-risk features 1

Surgical Considerations

• Surgical intervention (repair preferred over replacement) indicated for:
  • Symptomatic severe MR
  • Asymptomatic severe MR with LV dysfunction (EF <60%)
  • LV end-systolic dimension ≥40 mm
  • New onset atrial fibrillation
  • Pulmonary hypertension (pulmonary artery systolic pressure >50 mmHg) 1

MVP remains an important clinical entity requiring careful evaluation and individualized management based on symptoms, degree of regurgitation, and presence of complications.