Mitral valve prolapse: symptoms, causes, treatment and follow-up

The mitral valve controls blood movement from the left atrium into the left ventricle. A Leeds Teaching Hospitals leaflet describes it as a one-way valve. When the ventricle squeezes, the valve should shut tightly. In prolapse, the flaps are floppy or redundant, so they billow backwards toward the atrium, and sometimes they do not meet properly.

The NHS explains that heart valve disease happens when a valve does not open fully (stenosis) or does not close fully (prolapse), and may be leaky (regurgitation). Prolapse and leaking are therefore related but not identical: some people have a prolapsed valve with no meaningful leak, others have a prolapse that causes mitral regurgitation, which is a leak of blood backwards into the upper chamber.

In echo reports you may see the term "myxomatous" valve. The Patient reference describes this as thickening and redundancy of the leaflets and notes that the underlying mechanism is not known; prolapse can also occur with valves that look normal under the microscope.

Most people have no symptoms. The doctor-facing Patient page says that where symptoms of autonomic dysfunction appear, in people with a genetically inherited form, they can include anxiety, panic attacks, palpitations, fainting or near-fainting and neuropsychiatric symptoms. That is described as a feature of some inherited cases rather than of everyone with prolapse.

When the valve leaks substantially, the symptoms resemble those of other heart valve disease. The NHS lists shortness of breath, tiredness or weakness, dizziness, palpitations, swollen ankles and feet and chest pain or discomfort. Because these symptoms have many causes, the NHS advises seeing a GP rather than assuming a valve cause, and calling 999 or going to A&E for severe breathlessness or sudden chest pain that spreads to the arms, back, neck or jaw or lasts more than 15 minutes.

• Palpitations and awareness of the heartbeat are common reasons people are checked, but they are not specific to prolapse.

• A mid-to-late systolic click, sometimes followed by a murmur, is the classic examination finding described by the Patient reference.

• New breathlessness on exertion, swollen ankles, or fainting deserves review rather than waiting for the next routine scan.

The cause is often multifactorial and the Patient reference suggests there is probably a familial pattern in some people, with variable expression. It can sit alongside certain connective tissue conditions: the page names Marfan syndrome, Ehlers-Danlos syndrome, osteogenesis imperfecta, pseudoxanthoma elasticum and adult polycystic kidney disease, and also an unrepaired atrial septal defect of the secundum type.

Features that may prompt an examiner to look for prolapse include low body weight, a sunken breastbone (pectus excavatum), very flexible joints and an arm span longer than height, although the page stresses that examination alone is not specific. Having one of these features does not mean you have a heart valve problem.

A GP listens to the heart and, if there is a click or murmur, arranges further tests or a cardiology referral. The NHS lists an echocardiogram, chest X-ray and ECG as tests you may have. For prolapse specifically, the Patient reference says that people with signs should have a 2-D echocardiogram, which shows the prolapse and separates it from other causes of a systolic click, and it stresses that strict echo criteria are needed to avoid over-diagnosis.

The same page notes that a transthoracic echo can miss prolapse of some parts of the valve, in which case a transoesophageal echo, where a probe passes into the gullet under sedation, may show more. The ECG and chest X-ray are usually normal unless leakage has become significant, and an ambulatory 24-hour ECG can be used if rhythm disturbance is suspected.

The Patient reference groups people by the chance that severe leakage develops. Those with no symptoms, only mild leakage and stable findings need no treatment and can be followed conservatively. Features that raise the likelihood of progression include age over 50, hypertension or obesity, moderate-to-severe regurgitation, leakage that appears only during exercise, thick leaflets on the scan, posterior leaflet prolapse, larger heart chamber size, atrial fibrillation, reduced pumping function and an enlarged left atrium.

These details help the cardiology team decide how often to look again; they are not a self-assessment checklist. The Leeds leaflet on mitral regurgitation adds that with no symptoms you are likely to be reviewed with clinic visits and echocardiograms from time to time because valve disease can progress, that mild leakage often needs little long-term monitoring, and that sometimes mild leakage is considered normal and does not need surveillance.

Most people need no treatment. The Patient reference says that autonomic-type symptoms may be treated with a trial of beta-blockers and by cutting out caffeine, alcohol and cigarettes, and that antithrombotic treatment is not recommended for prolapse alone. Medicines for symptomatic valve disease more generally, as listed by the NHS, include ACE inhibitors, diuretics, drugs to slow the heart and anticoagulants; the choice depends on the individual.

If severe regurgitation develops, the Leeds leaflet says tests are done to decide between mitral valve repair, replacement or a transcatheter (keyhole) approach. Repair modifies the existing valve so it leaks less, while replacement removes it and uses a tissue or mechanical valve. The Patient reference says that repair is associated with excellent long-term survival and is considered superior to replacement where it can be done, and that timing of surgery is a specialist judgement. Whether any particular transcatheter technique is offered is a matter for the heart team.

Most people with mitral valve prolapse and no significant leak are not affected by pregnancy, but the sources here talk about heart valve disease in general, which is where leakage matters. The NHS says pregnancy can make heart valve disease symptoms worse, and that you can usually have a safe pregnancy but may need extra monitoring and treatment.

The British Heart Foundation says that with planning, most people with heart valve disease will not have any complications during pregnancy, and that it is important to tell your doctor if you are pregnant or planning to have a family. Leeds Teaching Hospitals advises discussing it with your healthcare professional before getting pregnant and letting them know immediately if you become pregnant.

The Patient reference states that overall the outlook is excellent. It also lists small absolute risks: an increase in the risk of sudden cardiac death that is described as very low in absolute terms, a small increased risk of infective endocarditis (similar to the general population when there is no leak), and a possible increased risk of stroke. These points are mostly relevant to people with leakage or high-risk features and should be discussed with a cardiologist rather than read as a personal forecast.

Good dental health is recommended for anyone with an abnormal valve, because bacteria from the mouth can cause endocarditis. The Patient reference quotes NICE as saying routine antibiotic prophylaxis is not required for most procedures, and that people at risk should know the symptoms of endocarditis, such as unexplained fever. Pregnancy generally needs a conversation with a doctor in advance if there is significant valve disease.