Mitral Valve Regurgitation

The mitral valve is located on the left side of the heart between the upper chamber (atrium) and the lower chamber (ventricle). When the mitral valve functions normally, it allows blood to flow only in one direction, from the left atrium to the left ventricle. From the left ventricle, blood moves out to the body.

 

 

 

 

 

Figure 1:  Normal mitral valve

In a heart with mitral regurgitation (also referred to as a "leaky valve"), the valve does not function normally. The valve allows some blood to leak back into the atrium so the heart has to work harder to supply enough blood to the body. As the leak progresses, the heart's function continues to decrease and symptoms are noted by the patient. See How It Effects Your Body.

A leaky valve can be caused by damage to the valve itself, or as a result of an underlying cardiac condition which triggers changes to the size and/or shape of the heart (remodeling). Mitral regurgitation (leaky valve) is classified in one of two categories:

  • Structural / Degenerative Mitral Regurgitation
    If the valve itself is structurally abnormal (such as Mitral Valve Prolapse Syndrome or a congenitally malformed valve), has been damaged (as a result of infection or by rheumatic fever), or is "degenerating" due to the normal aging process, the mitral regurgitation is considered structural or degenerative.
  • Functional Mitral Regurgitation (FMR)
    If the valve is structurally normal (functional), but leaks because of changes to the size and/or shape of the heart (remodeling) or damage to the heart muscle from coronary artery disease or a heart attack, the mitral regurgitation is considered functional.

What causes FMR?

 

Figure 2: An initial event such as a heart attack (depicted in blue) damages the heart

 

Figure 3: The heart begins to enlarge because the damaged heart cannot pump enough blood to the body

 

Figure 4: Eventually, the heart gets so big that the mitral valve cannot close properly and FMR develops