Mitral Regurgitation

Leaking of the mitral valve

Mitral regurgitation is a disorder in which the heart valve that separates the upper and lower chambers on the left side of the heart does not close properly. Regurgitation means leaking from a valve that does not close all the way.  Mitral regurgitation is the most common type of heart valve disorder.

Causes of Mitral Regurgitation

Blood that flows between different chambers of the heart must flow through a valve. The valve between the two chambers on the left side of your heart is called the mitral valve. When the mitral valve doesn't close all the way, blood leaks backward into the upper heart chamber (atrium) from the lower chamber as it contracts.

The increased pressure in this upper heart chamber can cause shortness of breath. The leak, or regurgitation, also leads to a decrease in blood flow to the rest of the body. As a result, the heart may try to pump harder. This may lead to congestive heart failure.

Mitral regurgitation most frequently is a problem with the valve leaflets. It can begin slowly and both the leak and the symptoms will gradually increase over time. Mitral regurgitation may also begin suddenly, most often after a heart attack. When the regurgitation does not go away, it becomes long-term (chronic).

Many other diseases or problems can weaken or damage the valve or the heart tissue around the valve and cause mitral regurgitation:

  • Mitral valve prolapse (MVP)
  • Coronary heart disease and high blood pressure
  • Infection of the heart valves
  • Rare causes, such as untreated syphilis or Marfan syndrome
  • Rheumatic heart disease, a complication of untreated strep throat (which is becoming less common because of effective treatment)
  • Swelling of the left lower heart chamber

Risk factors include a personal or family history of any of the disorders mentioned above, and use of fenfluramine and dexfenfluramine (appetite suppressants banned by the FDA) for four or more months.

Symptoms of Mitral Regurgitation

Symptoms may begin suddenly if:
  • A heart attack damages the muscles around the mitral valve.
  • The cords that attach the muscle to the valve break.
  • An infection of the valve destroys part of the valve.

There are often no symptoms. When symptoms occur, they often develop gradually, and may include:

  • Shortness of breath that increases with activity or when lying down
  • Sensation of feeling palpitations or a rapid heart beat
  • Cough
  • Fatigue, exhaustion and light-headedness
  • Rapid breathing
  • Urination, excessive at night

When listening to your heart and lungs, your doctor may detect:

  • A thrill or vibration over the heart when feeling the chest area
  • An extra heart sound (S4 Gallop)
  • A distinctive heart murmur
  • Crackles in the lungs (if fluid backs up into the lungs)

A physical exam may also reveal ankle swelling, enlarged liver, bulging neck veins and other signs of right-sided heart failure.