Mitral Valve Prolapse

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What is Mitral Valve Prolapse

Mitral valve prolapse is a heart condition involving the mitral valve. This is the valve between the upper chamber (atrium) and the lower chamber (ventricle) on the left side of the heart.

Normally, the mitral valve allows blood to flow from the atrium to the ventricle and then seals off the chambers from one another. If you have mitral valve prolapse, the valve does not work the way that it should. The flaps of the mitral valve do not form a tight seal between the atrium and the ventricle. When this happens, blood can flow the wrong way (mitral valve regurgitation). This causes symptoms of mitral valve prolapse.

16 Interesting Facts of Mitral Valve Prolapse

Mitral valve prolapse is an abnormal systolic bulging or billowing of 1 or both leaflets of the mitral valve toward the left atrium during systole; it is the most common cause of mitral regurgitation requiring surgery in many countries
Most patients are asymptomatic; severe mitral regurgitation develops in a minority of patients and may result in exertional dyspnea or fatigue
Nonspecific symptoms such as palpitations, chest pain, dyspnea, dizziness, and anxiety may be attributed to mitral valve prolapse but are not reliable indicators of its presence
Auscultation may find a murmur of mitral regurgitation and nonejection click; some patients with mitral valve prolapse have only a click or a murmur, whereas others may have no abnormality evident on auscultation
Prolapse is diagnosed on 2-dimensional transthoracic or transesophageal echocardiography when 1 or both mitral leaflets exhibit 2 mm or more of systolic displacement above the annular plane in long-axis view (5 mm or larger in 4-chamber view)
Most asymptomatic patients with or without mild mitral regurgitation can be managed conservatively. Symptomatic patients with severe mitral regurgitation, impaired left ventricular systolic function, or severe or progressive symptoms generally require surgical intervention; mitral valve repair is the preferred procedure
Most patients have an excellent prognosis with an expected survival similar to that of the general population and do not develop symptoms or other significant echocardiographic abnormalities
Antibiotic prophylaxis for infective endocarditis is not recommended for patients unless they have previously been diagnosed with endocarditis
Autosomal dominant condition that can be caused by a mutation in the FBN1 gene in some patients; presents with mitral valve prolapse and subtle skeletal features similar to those of Marfan syndrome (eg, pectus excavatum, scoliosis, mild arachnodactyly)
Diagnosis is difficult to discriminate from emerging Marfan syndrome; therefore, it is usually established in patients aged 20 years or older
In contrast with Marfan syndrome, patients do not develop significant aortic root dilation or ectopia lentis
Differentiate from Marfan syndrome by clinical manifestations and course of disease (eg, absence of significant aortic dilation, absence of ectopia lentis)
Definitive diagnosis is established in patients aged 20 years or older with mitral valve prolapse whose condition does not meet Ghent criteria for Marfan syndrome and who have the following: Aortic root z score less than 2
Systemic score less than 5
Absence of development of ectopia lentis
Presence of family history with concordant manifestations confirms the diagnosis

This condition can develop if:

The mitral valve flaps are larger and thicker than normal.
The valve opening stretches abnormally.
The valve flaps flop or bulge more than they should.

What are the causes?

The cause of this condition is not known. However:

It is sometimes passed down (inherited) from a family member who also had the condition.
It can be a complication of other diseases.

What increases the risk?

This condition is more like to develop in people with:

A family history of mitral valve prolapse.
Muscular dystrophy.
Graves disease.
Scoliosis.
A connective tissue disorder.

What are the symptoms?

Symptoms of this condition include:

A fast or irregular heartbeat (palpitations).
Fatigue.
Dizziness.
Shortness of breath.
Discomfort in the chest area.

In some cases, there are no symptoms for this condition.

How is this diagnosed?

This condition may be diagnosed based on:

Your symptoms and medical history.
A physical exam, which includes listening to your heart with a stethoscope.
Other tests to confirm the diagnosis. These may include imaging studies of your heart, such as:
- X-rays. These check for fluid in the lungs.
- Echocardiogram. This test uses sound waves to show the size of your heart and how well it pumps.
- Doppler ultrasound. This test uses sound waves to take pictures of the blood flow through your valve.
- Electrocardiogram (ECG). This test records the electrical activity of your heart.

How is this treated?

Treatment for this condition depends on how severe your symptoms are. If you need treatment, the goal is to relieve symptoms and prevent further problems, such as a type of heart infection called endocarditis. Treatment can include:

Medicines. You may need to take:
- Beta blockers. These help with chest discomfort and palpitations.
- Vasodilators. These improve forward blood flow through the valve, if it is leaking.
- Water pills (diuretics). These get rid of any extra fluid that is present.
Surgery to repair or replace the mitral valve.

If you do not have symptoms, you may not need treatment.

Follow these instructions at home:

Take over-the-counter and prescription medicines only as told by your health care provider.
Get regular exercise. Ask your health care provider to recommend some activities that are safe for you to do.
Do not use any products that contain nicotine or tobacco, such as cigarettes and e-cigarettes. If you need help quitting, ask your health care provider.
Avoid being around secondhand smoke.
Brush and floss your teeth every day. See a dentist regularly. Having unhealthy teeth and gums may make endocarditis more likely.
Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if:

You have any kind of abnormal heartbeat.
You are often very tired.
You have a cough that will not go away.
Your symptoms of mitral valve prolapse begin to get worse.

Get help right away if:

You have chest pain or shortness of breath.
You start to have chills, body aches, and a fever.

Pitfalls

Nonspecific symptoms such as palpitations, chest pain, dyspnea, dizziness, and anxiety have been attributed to mitral valve prolapse (sometimes called mitral valve prolapse syndrome); however, it remains unclear whether mitral valve prolapse is directly related to the symptoms or incidental. Other causes for cardiac symptoms should be excluded

Mitral valve prolapse is an abnormal systolic bulging or billowing of 1 or both leaflets of the mitral valve toward the left atrium during systole

Most common cause of mitral regurgitation requiring surgery in many countries

Classification

By cause
- Primary mitral valve prolapse
  - Typically caused by myxomatous degeneration of mitral valve in the absence of a known connective tissue disorder
- Secondary mitral valve prolapse
  - Occurs in the presence of another disorder, usually a connective tissue disorder such as Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome, osteogenesis imperfecta, or pseudoxanthoma elasticum
    - Also observed in congenital heart disease, hypertrophic cardiomyopathy, acute rheumatic valvulitis, acute myocardial ischemia, and infective endocarditis
By clinical manifestation
- Syndromic
  - Mitral valve prolapse associated with extracardiac manifestations such as pectus excavatum
- Nonsyndromic
  - Isolated mitral valve prolapse
By severity of valve prolapse
- Billowing leaflets (tips remain in left ventricle)
- Flail leaflets (tip of 1 or both valve leaflets prolapses into left atrium)
By echocardiographic morphology
- Classic
  - Marked and diffusely thickened valve leaflets (5 mm or larger) with bileaflet prolapse
- Nonclassic
  - Limited or no thickening of valve leaflets (smaller than 5 mm) and segmental prolapse
By severity of associated mitral regurgitation
- Stage A (at risk of developing mitral regurgitation)
  - Asymptomatic
  - Mild abnormalities of mitral valve structure or function (mild mitral valve prolapse with normal coaptation)
  - No hemodynamic effects
- Stage B (progressive mitral regurgitation)
  - Asymptomatic
  - More severe valvular abnormalities (severe mitral valve prolapse with normal coaptation)
  - Mild enlargement of left atrium; no enlargement of left ventricle
  - Normal pulmonary pressure
- Stage C (asymptomatic severe mitral regurgitation)
  - Asymptomatic
  - Severe mitral valve prolapse with loss of coaptation or flail leaflet
  - Severe mitral regurgitation based on assessment of several echocardiographic parameters
  - Left atrial and left ventricular enlargement
  - Pulmonary hypertension may be present
  - Subgroups
    - Stage C1: not associated with left ventricular dysfunction (left ventricular end systolic diameter less than 40 mm and left ventricular ejection fraction greater than 60%)
    - Stage C2: associated with left ventricular dysfunction (left ventricular end systolic diameter of 40 mm or larger and left ventricular ejection fraction of 60% or less)
- Stage D (symptomatic severe mitral regurgitation)
  - Symptomatic
  - Severe mitral valve prolapse with loss of coaptation or flail leaflet
  - Severe mitral regurgitation based on assessment of several echocardiographic parameters
  - Left atrial and left ventricular enlargement
  - Pulmonary hypertension

Clinical Presentation

History

Asymptomatic in most instances
Severe mitral regurgitation develops in a minority of patients and may result in dyspnea (at rest or on exertion), reduced exercise tolerance, or fatigue
Nonspecific symptoms such as palpitations, chest pain, dyspnea, dizziness, and anxiety have been attributed to mitral valve prolapse (sometimes called mitral valve prolapse syndrome); however, these symptoms do not reliably indicate presence of mitral valve prolapse

Physical examination

Auscultation may find a murmur of mitral regurgitation and nonejection click
- Click of mitral valve prolapse is a brief, high-pitched sound that occurs at least 0.14 seconds after S₁
  - Unlike systolic ejection click, mitral valve prolapse click can be detected after beginning of upstroke of carotid pulse
  - Multiple clicks may be heard, possibly corresponding to tensing of chordae tendineae and prolapsing leaflets
- Click may be followed by a mid- to late-crescendo systolic murmur
  - Regurgitation is usually not severe if the murmur occurs in late systole
  - Holosystolic murmur suggests more severe regurgitation, in which case the click often disappears and the murmur is loud
- Some patients with mitral valve prolapse have only a click or a murmur; others may have no abnormality evident on auscultation
Dynamic auscultation
- Maneuvers that cause the click or murmur to occur earlier in systole: standing from supine position, performing a submaximal isometric handgrip exercise, or straining during Valsalva maneuver
- Maneuvers that delay the click and murmur (eg, squatting from upright position)

Causes

Mitral valve prolapse is a multifactorial valvular aberration that can be caused by abnormalities of valvular tissue, geometric disparities between left ventricle and mitral valve, and connective tissue disorders
- Most common cause is myxomatous degeneration of connective tissue within the mitral valve, resulting in thickening and redundancy of the valve leaflets
- Fibroelastic deficiency of a single leaflet segment is a less common cause and is more often seen in patients older than 70 years
- Associated connective tissue disorders include:
  - Marfan syndrome
  - Ehlers-Danlos syndrome
  - Pseudoxanthoma elasticum
  - Loeys-Dietz syndrome
  - Osteogenesis imperfecta
- Other causes
  - Acute rheumatic valvulitis has been described as a cause of valve prolapse in areas where rheumatic fever is endemic
    - Chronic rheumatic valve disease is not associated with valve prolapse
  - Acute and subacute bacterial endocarditis may result in ruptured chordae and flail mitral valve prolapse
  - Acute myocardial ischemia or infarction involving a papillary muscle may result in leaflet prolapse

Risk factors and/or associations

Age

Predominantly affects middle-aged adults; prevalence is low among children and young adults

Sex

Prevalence of echocardiographic mitral valve prolapse is equally distributed between men and women in some studies
- Other studies using similar echocardiographic criteria have found higher prevalence in women
Complications have been reported more frequently in men; clinical features may be milder in women

Genetics

Most cases are sporadic; however, a familial form may be inherited as an autosomal dominant trait. A rare, X-linked form of mitral valve prolapse has also been discovered
Secondary mitral valve prolapse occurs in several inherited connective tissue disorders, including Marfan syndrome, Ehlers-Danlos syndrome, osteogenesis imperfecta, and pseudoxanthoma elasticum

Other risk factors/associations

Other valvular abnormalities (eg, tricuspid valve prolapse)
Thoracic skeletal abnormalities (eg, pectus excavatum, scoliosis) and low body mass index were found to be associated with mitral valve prolapse in earlier studies; however, this association has not been replicated in subsequent studies

Diagnose mitral valve prolapse based on cardiac auscultation and echocardiography; it may be an incidental finding
- Diagnosis is confirmed when 1 or both mitral leaflets exhibit 2 mm or more of systolic displacement above the annular plane in long-axis view (5 mm or larger in 4-chamber view) on 2-dimensional transthoracic or transesophageal echocardiography
Additional tests may be indicated to evaluate for arrhythmias or underlying ischemic heart disease, but these do not aid in diagnosis of mitral valve prolapse

Imaging

Echocardiography
- Recommended for diagnosing mitral valve prolapse, evaluating hemodynamic severity of mitral regurgitation, and assessing leaflet morphology and ventricular compensation
- Transthoracic echocardiography may not adequately visualize the entire mitral valve, and can miss the diagnosis; transesophageal echocardiography may be necessary if transthoracic echocardiography is nondiagnostic
- 3-dimensional transesophageal techniques may aid in delineating mitral valve anatomy and guiding valve repair; used preoperatively, intraoperatively, and in percutaneous valve interventions
- Doppler imaging is used to quantify the severity of mitral regurgitation, if present
Cardiac MRI
- Not first line imaging modality; however, it may be indicated to assess ventricular volumes and function, or to evaluate severity of mitral regurgitation when not satisfactorily imaged by transthoracic echocardiography

Functional testing

ECG
- Findings are often within reference range in patients with mitral valve prolapse and are generally not helpful in the diagnosis
- Most common abnormality is the presence of ST-T wave depression or T-wave inversion in the inferior leads (II, III, and aVF)
- Useful in diagnosing associated arrhythmias such as atrial fibrillation

Differential Diagnosis

Most common

Other mitral valve disorders causing mitral regurgitation (Related: )Mitral regurgitation
- Mitral regurgitation can be caused by a variety of pathologies that affect either the valve leaflets or the left ventricle, such as rheumatic mitral valve disease, ruptured chordae tendineae, dilated mitral annulus, papillary muscle dysfunction secondary to ischemic heart disease, cardiomyopathy, and hypertrophic obstructive cardiomyopathy
- Like mitral valve prolapse, mitral regurgitation typically produces a high-pitched, pansystolic murmur, best heard near the left ventricular apex
  - Some murmurs are late systolic or midsystolic
- Symptoms and signs specific to underlying cause may be present
- Differentiated based on history, physical examination, and echocardiographic findings
Aortic stenosis
- Obstruction of blood flow from left ventricle into aorta caused by narrowing of aortic valve
- Similar to mitral valve prolapse, associated with systolic murmur; however, aortic stenosis typically has peak intensity in midsystole and is heard best at the left sternal border or base
- May have a systolic click, but typically occurs earlier in systole and is not affected by dynamic maneuvers
- Differentiated based on history, physical examination, and echocardiographic findings
Tricuspid valve prolapse
- Like mitral valve prolapse, may be associated with midsystolic click on auscultation; may be heard best at lower left sternal border
- Rare in isolation, but may coexist with mitral valve prolapse
- Differentiated based on echocardiographic findings

Treatment Goals

Treat mitral regurgitation and prevent complications

Disposition

Admission criteria

Admit for surgical treatment of mitral regurgitation, if indicated

Criteria for ICU admission

After valvular surgery

Recommendations for specialist referral

Refer to cardiologist if echocardiography shows significant or progressive mitral regurgitation
Referral to cardiothoracic surgeon for valvular surgery may be needed for patients who have severe or progressive symptoms, or severe mitral regurgitation

Treatment Options

Most asymptomatic patients with mitral valve prolapse with or without mild mitral regurgitation can be managed conservatively

Provide reassurance about benign prognosis
Recommend healthy lifestyle and regular exercise
No drugs or other therapies are needed

Antibiotic prophylaxis for infective endocarditis is not recommended unless the patient has had a history of known endocarditis

Antiplatelet therapy or anticoagulation is not required unless patients have other indications (eg, history of transient ischemic attack or stroke, concomitant atrial fibrillation)

Exclude other causes of symptoms in patients with mitral valve prolapse and nonspecific symptoms (eg, palpitations, atypical chest pain)

Consider lifestyle changes such as avoidance of alcohol and stimulants
β-adrenergic blockers may alleviate symptoms such as palpitations, anxiety, or chest pain in some patients

Manage mitral regurgitation associated with mitral valve prolapse as for other forms of mitral regurgitation

Symptomatic patients with mitral valve prolapse and severe mitral regurgitation (stage D), impaired left ventricular systolic function, or severe or progressive symptoms generally require surgical intervention
Surgical intervention is also recommended for asymptomatic patients with mitral valve prolapse and severe mitral regurgitation (stage C) in the presence of impaired left ventricular systolic function; surgery is considered reasonable in the absence of left ventricular dysfunction/dilation if there is a high likelihood of a successful and durable repair and an expected mortality less than 1%
Mitral valve repair is recommended over mitral valve replacement and may be performed using a variety of techniques, including leaflet resection, plication, artificial chords, and leaflet reduction (eg, sliding plasty for posterior leaflet, annuloplasty band or ring)
Transcatheter mitral valve repair may be considered for patients with severe mitral regurgitation who are severely symptomatic despite optimal medical therapy and who have prohibitive surgical risk because of severe comorbidities, provided that they have favorable anatomy for the repair procedure and a reasonable life expectancy

Nondrug and supportive care

Procedures

Mitral valve repair

General explanation

Mitral valve repair is the procedure of choice whenever possible and may be performed via open cardiac surgery, minimally invasive approaches, or percutaneous catheter
A variety of techniques may be used, including leaflet resection, plication, artificial chords, and leaflet reduction (eg, sliding plasty for posterior leaflet, annuloplasty band or ring)

Indication

Symptomatic patients with mitral valve prolapse and severe mitral regurgitation, impaired left ventricular systolic function, or severe or progressive symptoms
Asymptomatic patients with mitral valve prolapse and severe mitral regurgitation in the presence of impaired left ventricular systolic function (also considered reasonable in the absence of left ventricular dysfunction/dilation if there is a high likelihood of a successful and durable repair and an expected mortality less than 1%)

Special populations

Athletes
- Mitral valve prolapse is characterized by a mostly favorable prognosis and low event rate
  - Sudden cardiac death caused by isolated mitral valve stenosis is rare among young patients, particularly in relation to exercise, and trained athletes, and is probably not more frequent than in the general population
- Athletes with mitral valve prolapse causing mitral regurgitation should undergo yearly physical examinations, Doppler echocardiography, and exercise stress testing to at least the level of activity that approximates the exercise demands of the sport
- Athletes with mitral valve prolapse can engage in all competitive sports; however, if they have any of the following, participation is limited to low-intensity competitive sports only:
  - Prior syncope, judged likely to be arrhythmogenic in origin
  - Sustained or repetitive and nonsustained supraventricular tachycardia, or frequent and/or complex ventricular tachyarrhythmias on ambulatory Holter monitoring
  - Severe mitral regurgitation assessed with Doppler flow imaging
  - Left ventricular systolic dysfunction (ejection fraction less than 50%)
  - Prior embolic event
  - Family history of mitral valve prolapse–related sudden death

Monitoring

Clinically evaluate asymptomatic patients with mitral valve prolapse at regular intervals:
- No mitral regurgitation: every 3 to 5 years
- Mitral regurgitation: at least annually
Repeat echocardiography based on presence and severity of mitral regurgitation; change in physical findings suggesting progression of mitral regurgitation warrants earlier/more frequent echocardiography
- Severe mitral regurgitation (stage C): every 6 to 12 months
- Moderate mitral regurgitation (stage B): every 1 to 2 years
- Mild mitral regurgitation (stage B): every 3 to 5 years
- No mitral regurgitation (Stage A): indicated if new cardiovascular symptoms or physical findings suggesting significant development of significant mitral regurgitation

Complications

Complications are rare, but they include:
- Severe mitral regurgitation (Related: Mitral regurgitation)
- Ruptured mitral valve chordae
- Atrial fibrillation
- Infective endocarditis (Related: Endocarditis)
- Central nervous system embolic events (Related: Ischemic stroke)
- Congestive heart failure (Related: Heart failure)
- Pulmonary hypertension
- Sudden death (rare); occurs predominantly in patients older than 50 years with severe mitral regurgitation and/or systolic dysfunction

Prognosis

Reported prognosis has varied widely in published literature and is subject to ongoing debate
Most patients have an excellent prognosis with an expected survival similar to that of the general population
- Majority do not develop symptoms or other significant echocardiographic abnormalities
Earlier studies demonstrated that a small percentage of patients develop significant mitral regurgitation requiring surgical intervention
- However, in the community-based Framingham Heart Study, 25% of patients with mitral valve prolapse progressed to significant mitral regurgitation over a period of 3 to 16 years
Greatest risks for adverse outcomes (eg, severe progressive mitral regurgitation requiring valve surgery, infective endocarditis, embolic events, atrial and ventricular tachyarrhythmias, sudden death) are associated with significant structural abnormality of mitral valve (classic mitral valve prolapse) with diffuse leaflet thickening, elongation, and redundancy, and in some cases ruptured chordae tendineae

Sources

Levine RA et al: Mitral valve disease–morphology and mechanisms. Nat Rev Cardiol. 12(12):689-710, 2015 Reference