What Is Heart Valve Disease?
Heart valve disease is a condition in which one or
more of your heart valves don't work properly. The heart has four valves: the
tricuspid (tri-CUSS-pid), pulmonary (PULL-mun-ary), mitral (MI-trul), and
aortic (ay-OR-tik) valves.
These valves have tissue flaps that open and close
with each heartbeat. The flaps make sure blood flows in the right direction
through your heart's four chambers and to the rest of your body.
Healthy Heart Cross-Section
The illustration shows a
cross-section of a healthy heart, including the four heart valves. The blue
arrow shows the direction in which oxygen-poor blood flows from the body to the
lungs. The red arrow shows the direction in which oxygen-rich blood flows from
the lungs to the rest of the body.
Birth defects, age-related changes, infections, or
other conditions can cause one or more of your heart valves to not open fully
or to let blood leak back into the heart chambers. This can make your heart
work harder and affect its ability to pump blood.
Overview
How the Heart Valves Work
At the start of each heartbeat, blood returning from
the body and the lungs fills the heart's two upper chambers. The mitral and
tricuspid valves are located at the bottom of these chambers. As the blood
builds up in the upper chambers, these valves open to allow blood to flow into
the lower chambers of your heart.
After a brief delay, as the lower chambers begin to
contract, the mitral and tricuspid valves shut tightly. This stops blood from
flowing backward.
As the lower chambers contract, they pump blood
through the pulmonary and aortic valves. The pulmonary valve opens to allow
blood to flow from the right lower chamber into the pulmonary artery. This
artery carries blood to the lungs to get oxygen.
At the same time, the aortic valve opens to allow
blood to flow from the left lower chamber into the aorta. This aorta carries
oxygen-rich blood to the body. As the contraction ends, the pulmonary and
aortic valves shut tightly. This stops blood from flowing backward into the
lower chambers.
For more information on how the heart pumps blood,
see the animation in the "Heart
Contraction and Blood Flow" section of the Diseases and Conditions Index
article on How the Heart Works.
Heart Valve Problems
Heart valves can have three basic kinds of problems:
- Regurgitation (re-GUR-ji-TA-shun), or backflow,
occurs when a valve doesnt close tightly. Blood leaks back into the
chamber rather than flowing forward through the heart or into an artery.
- In the United States, backflow
is most often due to prolapse. "Prolapse" is when the flaps of the valve flop
or bulge back into an upper heart chamber during a heartbeat. Prolapse mainly
affects the
mitral
valve, but it can affect the other valves as well.
- Stenosis (ste-NO-sis) occurs when the flaps of a
valve thicken, stiffen, or fuse together. This prevents the heart valve from
fully opening, and not enough blood flows through the valve. Some valves can
have both stenosis and backflow problems.
- Atresia (a-TRE-ze-AH) occurs when a heart valve
lacks an opening for blood to pass through.
You can be born with heart valve disease or you can
acquire it later in life. Heart valve disease that develops before birth is
called a congenital (kon-JEN-i-tal) valve disease. Congenital heart valve
disease can occur alone or with other
congenital
heart defects.
Congenital heart valve disease usually involves
pulmonary or aortic valves that don't form properly. These valves may not have
enough tissue flaps, they may be the wrong size or shape, or they may lack an
opening through which blood can flow properly.
Acquired heart valve disease usually involves the
aortic or mitral valves. Although the valve is normal at first, disease can
cause problems to develop over time.
Both congenital and acquired heart valve disease can
cause stenosis or backflow.
Outlook
Many people have heart valve defects or disease but
don't have symptoms. For some people, the condition will stay largely the same
over their lifetime and not cause any problems.
For other people, the condition will worsen slowly
over time until symptoms develop. If not treated, advanced heart valve disease
can cause
heart
failure, stroke, blood clots, or sudden death due to
sudden
cardiac arrest.
Currently, no medicines can cure heart valve
disease. However, lifestyle changes and medicines can relieve many of the
symptoms and problems linked to heart valve disease. They also can lower your
risk of developing a life-threatening condition, such as stroke or sudden
cardiac arrest. Eventually, you may need to have your faulty heart valve
repaired or replaced.
Some types of congenital heart valve disease are so
severe that the valve is repaired or replaced during infancy or childhood or
even before birth. Other types may not cause problems until you're middle-aged
or older, if at all.
December 2007 |