Written by Dimitrios Vrachatis, Specialist Cardiologist, PhD, National and Kapodistrian University of Athens.
What is mitral valve prolapse?
The mitral valve connects the left atrium and left ventricle. Its apparatus comprises two leaflets, papillary muscles and chordae tendineae. The leaflets open during ventricular relaxation and then close tightly.
Mitral valve prolapse occurs when one or both leaflets bulge more than 2 mm into the left atrium during ventricular contraction.
How common is it?
It affects approximately 1–2.4% of the general population, equally in women and men, contrary to earlier beliefs.
What is the prognosis?
The prognosis is benign. Risks may arise if complications develop. Ten-year mortality risk is estimated at 2.5–5%.
What complications can occur?
The main complication is mitral regurgitation. The risk of chronic severe regurgitation is estimated at 5–10%.
Other potential complications usually result from mitral regurgitation, if it develops, and include:
- Heart failure
- Pulmonary hypertension
- Atrial arrhythmias, such as atrial fibrillation, and ventricular arrhythmias
- Rarely, sudden cardiac death. This is reported mainly in patients with high-risk features:
- Severe mitral regurgitation
- Prolapse of both leaflets
- Long QT or inferior T-wave inversion on the electrocardiogram
- Documented dangerous arrhythmias
- Left ventricular dysfunction
- Inferior or inferolateral myocardial scarring or fibrosis
- Excessive movement at the junction of the valve and left atrium, known as mitral annular disjunction (MAD)
- A family history of sudden death
How is it diagnosed?
It is usually an incidental finding during an echocardiogram.
What are the symptoms?
Several conditions were previously associated with prolapse, but newer evidence has not confirmed these links. Isolated mitral valve prolapse usually causes no symptoms and is discovered incidentally.
Some people nevertheless report palpitations, chest pain, breathlessness, dizziness or feeling faint.
Is it associated with extra beats or stroke?
Earlier assumptions of an increased arrhythmia burden or transient ischaemic attacks have not generally been confirmed. Such complications are rare and occur when prolapse has particular features, including mitral annular disjunction (MAD).
Classification
Prolapse is classified as primary or secondary.
Primary Mitral Valve Prolapse
It is further divided into:
Mitral valve prolapse syndrome: typically seen in women aged 20–50, with thin leaflets and mild prolapse. Low blood pressure, postural hypotension and palpitations may coexist. The course is usually benign.
Myxomatous degeneration, or Barlow’s syndrome: usually seen in men aged 40–70, with thickened leaflets, marked prolapse and an increased likelihood of regurgitation, which may progressively worsen and require surgery.
Secondary Mitral Valve Prolapse
Secondary prolapse is associated with a mismatch between mitral annular and left ventricular dimensions. It is usually seen in young women, improves with age and generally does not cause regurgitation.
It may also occur with:
- Connective tissue disorders: 90% in Marfan syndrome and over 6% in Ehlers–Danlos syndrome
- Osteogenesis imperfecta
- Atrial septal defect
- Hyperthyroidism
- Emphysema
- Obstructive hypertrophic cardiomyopathy
Secondary prolapse is usually of little clinical significance and is not associated with severe regurgitation.
Is treatment needed?
Isolated prolapse requires no specific medication.
Could surgery be needed?
Any intervention relates to mitral regurgitation, when present.
Which tests do I need?
Alongside regular echocardiography, an electrocardiogram should be performed.
Pre-participation sports screening should include an exercise stress test and 24-hour Holter monitoring. If the ECG shows inferior T-wave inversion or extra beats originating in the left ventricle, cardiac MRI should also be performed.
How often should I be checked?
The cited guidance recommends reassessment approximately every three years, more frequently if regurgitation coexists. New symptoms require immediate reassessment.
Mitral Valve Prolapse and Exercise
The generally benign prognosis permits sports participation even with mild or moderate regurgitation, provided the assessment above shows no high-risk features.
With severe regurgitation, intense exercise is prohibited. Lower-intensity activities have restrictions based on individual characteristics.
Mitral Valve Prolapse and Dental Treatment
The cited European Society of Cardiology guidelines (2015) classify prolapse as an intermediate risk for infective endocarditis, somewhat above that of the general population. Nevertheless, they advise against preventive antibiotics for dental procedures. Good oral hygiene remains important.
Mitral Valve Prolapse and Pregnancy
Isolated prolapse without high-risk features is classified as category I on the modified World Health Organization scale.
It is considered not to increase mortality during pregnancy, although morbidity may be slightly increased in some cases, at 2.5–5%. Delivery can take place in a local hospital, with cardiology assessment once or twice during pregnancy.
Should I be worried?
For most people, mitral valve prolapse is a benign condition that will not change their lives or cause concern beyond occasional routine follow-up. There is no reason for anxiety.