Mitral valve prolapse (MVP, click-murmur syndrome, Barlow syndrome, or floppy valve syndrome) is a common and typically benign valvular heart condition occurring as a result of the mitral valve flaps failing to close normally in a smooth or tight manner; instead, they appear floppy. The majority of MVP cases are harmless; the patients are asymptomatic and require no treatment. In some cases, treatment is required.

MVP most commonly occurs due to small, tumor-like collagen growths on the valve leaflets (myxomatous changes). An individual may be born with MVP, and it may run in families. MVP may also be caused by other conditions such as Marfan syndrome, Ehlers-Danlos syndrome, Ebstein anomaly, muscular dystrophy, Graves disease, and scoliosis.

MVP occurs in about 2%-4% of the general population and may develop at any age. Serious symptoms occur most frequently in males over age 50.

Clinical presentation is variable, but when patients are symptomatic, they may experience palpitations, dizziness, lightheadedness, or dyspnea when lying flat or during exercise, fatigue, and chest pain not caused by coronary artery disease or heart attack.

MVP complications are rare, but they may occur. Some complications include arrhythmia and infective endocarditis.   

If a patient has severe MVP with or without symptoms, surgery may be suggested to repair or replace the mitral valves. Medications may also be used to treat symptoms and prevent complications.