Mitral Valve Prolapse

Mitral valve prolapse (MVP), a very common heart condition, occurs when one of the heart's valves doesn't work properly. MVP can be frightening because it involves the heart and can cause sharp chest pains, but it isn't a critical heart problem or a sign of other serious medical conditions.

Because MVP often doesn't produce any symptoms or interfere with everyday life, in many cases it isn't diagnosed until adulthood. But with kids who are diagnosed, it's important to know what the symptoms are, so that you can distinguish them from signs of any other more serious heart issues.

What Is the Mitral Valve?

To understand mitral valve prolapse, it's helpful to review some basics about the way a healthy heart works.

• The heart is made up of four distinct chambers: two atria (the two upper chambers) and two ventricles (the two lower chambers).
• During circulation, blood flows from all over the body into the heart's right atrium.
• From there the blood travels to the right ventricle, which pumps the blood to the lungs to receive oxygen.
• Once the blood has been infused with oxygen, it returns from the lungs to the heart's left atrium.The oxygen-rich blood then passes into the left ventricle, which pumps it out to the body through a large blood vessel known as the aorta.

The mitral valve is located between the left atrium and the left ventricle and helps control the flow of blood as it passes from the left atrium into the left ventricle. The valve has two flaps of tissue — known as leaflets — that open and close together like a pair of swinging doors. Each time the heart beats, the left ventricle pumps blood out to the body and the flaps of the mitral valve swing shut to prevent the blood in the ventricle from flowing backward into the left atrium.

In cases of MVP, one or both of the mitral valve's flaps bulge back into the atrium when they are shut, a bit like a balloon. This may occur because one of the flaps is abnormally shaped or a little too large.

In some cases, when the flaps do not close evenly, blood is allowed to leak back into the left atrium. This is called mitral regurgitation. A tiny amount of mitral regurgitation is normal. In some cases, there's more leakage, which can cause a heart murmur a whooshing sound between the normal lub-dub of the heartbeat. (Because of these sounds, MVP is sometimes called click-murmur syndrome, floppy valve syndrome, or balloon mitral valve.)

In most cases, the cause of MVP is unknown. Sometimes kids are born with the condition. In other cases, it develops after some sort of inflammatory condition, like endocarditis, an inflammation of the inner lining of the heart, or rheumatic fever, an inflammation that can affect the joints and the heart.

MVP may be diagnosed in people who have other health conditions that affect the body's connective tissue, such as Marfan sndrome. Some research has shown that kids with MVP may be more likely to also have an arrythmia, an irregular heartbeat.