Mitral Valve Regurgitation

Mitral valve regurgitation is the backward flow of blood through your heart’s mitral valve. This “door” connects the two chambers on the left side of your heart. It opens and closes when your heart beats. When your mitral valve opens, it lets blood flow from your top left chamber (atrium) down to your bottom left chamber (ventricle). When it closes, blood flow between those chambers pauses. The sealed door prevents blood from flowing back up into the top chamber so that it can go out of your heart to supply blood to your body.

But like other doors, your mitral valve can sometimes have trouble closing fully. This might be because of damage to the door itself (in this case, your valve tissue). Or, damage to the walls and structures surrounding the door (the left chambers of your heart) might keep it from working normally. In either case, your mitral valve can’t fully close. And some blood can leak out.

Doors in your heart can cause minor or serious issues depending on how wide the openings are. A minor leak in your mitral valve might not make much of a difference or cause you to worry. Your heart can easily compensate and you’ll feel fine. But if too much blood keeps leaking backward, your heart will have to work harder to send enough blood forward in the proper direction. Over time, this can take a toll on your heart, leading to symptoms and complications.

You may hear people refer to this condition by its shortened name, mitral regurgitation (MR). Other names include:

• Mitral valve insufficiency.
• Mitral valve incompetence.
• Leaky mitral valve.

Mitral valve regurgitation is the most common type of heart valve disease in the U.S. It’s especially common among people as they get older (over age 65).

Types of mitral valve regurgitation

There are two main types of mitral regurgitation:

• Primary mitral regurgitation. In this type, the problem is the valve itself. Structural damage to one or more parts of the valve prevents it from closing normally. For example, the valve leaflets may become too stretchy to form a tight seal or too stiff to close.
• Secondary mitral regurgitation. In this type, the problem is heart disease that affects the heart chambers that support the valve (the left atrium or ventricle). For example, cardiomyopathy can cause your heart to grow larger and weaker. These changes can shift the positioning of the different parts of your valve and prevent its leaflets from fully closing.

MR of either type may be:

• Acute, developing suddenly and severely.
• Chronic, developing gradually over time.