Causes
The mitral valve is the heart valve located between the upper and lower
chambers of the left side of the heart. The mitral valve is made up of two
flaps and controls the blood flow from the top chamber of the left side of the
heart (the left atrium) to its bottom chamber (the left ventricle). But in MVP,
one or both of the flaps are too big. The valve can't close properly and and
will bulge out or prolapse into the left atrium. With a stethoscope,
doctors may hear the soft "clicking" sound of the bulging. Sometimes
the bulging out causes a little space between the flaps which lets the blood
leak backwards into the left atrium from the ventricle. This leak can cause
a "whooshing" sound which can also be heard with the stethoscope.
MVP is sometimes inherited. Some people with MVP have minor deformities of
the chest, back and spine. In rare cases, inherited diseases such as Marfan's
syndrome have been associated with MVP.