What Is a Heart Murmur?
A heart murmur is an extra or unusual sound heard
during a heartbeat. Murmurs range from very faint to very loud. They sometimes
sound like a whooshing or swishing noise.
Normal heartbeats make a "lub-DUPP" or "lub-DUB"
sound. This is the sound of the heart valves closing as blood moves through the
heart. Doctors can hear these sounds and heart murmurs using a stethoscope.
Overview
There are two types of heart murmurs: innocent
(harmless) and abnormal.
People who have innocent heart murmurs have normal
hearts. They usually have no other signs or symptoms of heart problems.
Innocent murmurs are common in healthy children. Many, if not most, children
will have heart murmurs heard by their doctors at some time in their lives.
People who have abnormal murmurs may have other
signs or symptoms of heart problems. Most abnormal murmurs in children are due
to congenital
heart defects. These are heart defects that are present at birth.
In adults, abnormal murmurs are most often due to
heart
valve problems caused by infection, disease, or aging.
Outlook
A heart murmur isn't a disease, and most murmurs are
harmless. Innocent murmurs dont cause symptoms or require you to limit
physical activity. Although an innocent murmur may be a lifelong condition,
your heart is normal and you likely wont need treatment.
The outlook and treatment for abnormal heart murmurs
depends on the type and severity of the heart problem causing them.
How the Heart Works
The heart is a muscle about the size of your fist.
It works like a pump and beats 100,000 times a day.
The heart has two sides, separated by an inner wall
called the septum. The right side of the heart pumps blood to the lungs to pick
up oxygen. Then, oxygen-rich blood returns from the lungs to the left side of
the heart, and the left side pumps it to the body.
The heart has four chambers and four valves and is
connected to various blood vessels. Veins are the blood vessels that carry
blood from the body to the heart. Arteries are the blood vessels that carry
blood away from the heart to the body.
A Healthy Heart Cross-Section
The illustration shows a
cross-section of a healthy heart and its inside structures. 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.
Heart Chambers
The heart has four chambers or "rooms."
- The atria (AY-tree-uh) are the two upper chambers
that collect blood as it comes into the heart.
- The ventricles (VEN-trih-kuls) are the two lower
chambers that pump blood out of the heart to the lungs or other parts of the
body.
Heart Valves
Four valves control the flow of blood from the atria
to the ventricles and from the ventricles into the two large arteries connected
to the heart.
- The tricuspid (tri-CUSS-pid) valve is in the
right side of the heart, between the right atrium and the right ventricle.
- The pulmonary (PULL-mun-ary) valve is in the
right side of the heart, between the right ventricle and the entrance to the
pulmonary artery, which carries blood to the lungs.
- The mitral (MI-trul) valve is in the left side of
the heart, between the left atrium and the left ventricle.
- The aortic (ay-OR-tik) valve is in the left side
of the heart, between the left ventricle and the entrance to the aorta, the
artery that carries blood to the body.
Valves are like doors that open and close. They open
to allow blood to flow through to the next chamber or to one of the arteries,
and then they shut to keep blood from flowing backward.
When the heart's valves open and close, they make a
"lub-DUB" sound that a doctor can hear using a stethoscope.
- The first soundthe "lub"is made by
the mitral and tricuspid valves closing at the beginning of systole
(SIS-toe-lee). Systole is when the ventricles contract, or squeeze, and pump
blood out of the heart.
- The second soundthe "DUB"is made by
the aortic and pulmonary valves closing at beginning of diastole
(di-AS-toe-lee). Diastole is when the ventricles relax and fill with blood
pumped into them by the atria.
Arteries
The arteries are major blood vessels connected to
your heart.
- The pulmonary artery carries blood pumped from
the right side of the heart to the lungs to pick up a fresh supply of oxygen.
- The aorta is the main artery that carries
oxygen-rich blood pumped from the left side of the heart out to the body.
- The coronary arteries are the other important
arteries attached to the heart. They carry oxygen-rich blood from the aorta to
the heart muscle, which must have its own blood supply to function.
Veins
The veins also are major blood vessels connected to
your heart.
- The pulmonary veins carry oxygen-rich blood from
the lungs to the left side of the heart so it can be pumped out to the
body.
- The vena cava is a large vein that carries
oxygen-poor blood from the body back to the heart.
For more information on how a healthy heart works,
see the Diseases and Conditions Index
How
the Heart Works article. This article contains animations that show how
your heart pumps blood and how your heart's electrical system works.
Other Names for Heart Murmurs
Innocent Heart Murmurs
- Normal heart murmurs
- Benign heart murmurs
- Functional heart murmurs
- Physiologic heart murmurs
- Stills murmurs
- Flow murmurs
Abnormal Heart Murmurs
What Causes a Heart Murmur?
Innocent Heart Murmurs
Innocent heart murmurs are sounds heard when blood
flows through a normal heart. These murmurs may occur when blood flows faster
than normal through the heart and its attached blood vessels. Illnesses or
conditions that may cause this to happen include fever,
anemia
(uh-NEE-me-eh), and hyperthyroidism (too much thyroid hormone in the body).
Extra blood flow through the heart also may cause
innocent heart murmurs. After childhood, the most common cause of extra blood
flow through the heart is pregnancy. Most heart murmurs found in pregnant women
are innocent. Theyre due to the extra blood that women's bodies make
while theyre pregnant.
Changes to the heart that result from
heart
surgery or aging also may cause some innocent heart murmurs.
Abnormal Heart Murmurs
The most common cause of abnormal murmurs in
children is
congenital
heart defects. These are problems with the hearts structure that are
present at birth.
These defects can involve the interior walls of the
heart, the valves inside the heart, or the arteries and veins that carry blood
to the heart or out to the body. Some babies are born with more than one heart
defect. Congenital heart defects change the normal flow of blood through the
heart.
Heart
valve defects and septal defects (also called
holes
in the heart) are common heart defects that cause abnormal heart murmurs.
Valve defects may include narrow valves that limit
blood flow or leaky valves that dont close properly.
Septal defects are holes in the wall that separates
the right and left sides of the heart. This wall is called the septum.
A hole in the septum between the hearts two
upper chambers is called an atrial septal defect (ASD). A hole in the septum
between the hearts two lower chambers is called a ventricular septal
defect (VSD). ASDs and VSDs account for more than half of all abnormal heart
murmurs in children.
Heart Defects That Can Cause
Abnormal Heart Murmurs
Figure A shows the anatomy and blood
flow of the inside of a normal heart. Figure B shows a heart with leaking and
narrowed valves. Figure C shows a heart with a ventricular septal defect.
Conditions that damage heart valves or other
structures of the heart also may cause abnormal heart murmurs. These include
rheumatic (ru-MAT-ik) fever, endocarditis (EN-do-kar-DI-tis), calcification
(KAL-si-fi-KA-shun), and
mitral
(MI-tral) valve prolapse (MVP). Heart murmurs due to these problems are
more common in adults.
Rheumatic Fever
The bacteria that cause strep throat, scarlet fever,
and, in some cases, impetigo (im-peh-TI-go) also can cause rheumatic fever.
This serious illness can develop if a person has an untreated or not fully
treated strep infection.
Rheumatic fever can lead to permanent heart damage.
If you or your child has strep throat, take all of the antibiotics prescribed,
even if you feel better before the medicine runs out.
Endocarditis
Endocarditis is a serious infection of the heart
valves or lining of the heart. A bacterial infection usually causes
endocarditis, and it usually occurs in an abnormal heart. Endocarditis can lead
to permanent heart damage and other health problems.
Calcification
Calcification occurs when the hearts valves
get hard and thick as a result of aging. When this happens, the valves
dont work as they should.
Mitral Valve Prolapse
MVP is a condition in which the hearts mitral
valve doesnt work properly. In MVP, when the left ventricle contracts,
one or both flaps of the mitral valve flop or bulge back (prolapse) into the
left atrium. This can cause a heart murmur.
What Are the Signs and Symptoms of a Heart
Murmur?
Most people who have heart murmurs dont have
any other signs or symptoms of heart problems. These murmurs usually are
innocent (harmless).
Some people who have heart murmurs do have signs or
symptoms of heart problems. The signs and symptoms may include:
- Blue coloring of the skin, especially on the
fingertips and inside the mouth
- Poor eating and abnormal growth (in infants)
- Shortness of breath
- Excessive sweating
- Chest pain
- Dizziness or fainting
- Fatigue (feeling very tired)
Signs and symptoms depend on the problem causing the
murmur and how severe that problem is.
How Is a Heart Murmur Diagnosed?
Doctors use a stethoscope to listen to heart sounds
and hear heart murmurs. They often notice innocent heart murmurs during routine
checkups or physical exams.
Doctors also may find abnormal heart murmurs during
routine checkups. When a
congenital
heart defect causes a murmur, its often heard at birth or during
infancy. Abnormal murmurs caused by other heart problems can be heard in
patients of any age.
Specialists Involved
Doctors usually refer people who have abnormal
murmurs to cardiologists or pediatric cardiologists for further care and
testing.
Cardiologists are doctors who treat adults who have
heart problems. Pediatric cardiologists treat children who have heart problems.
Physical Exam
Your doctor will carefully listen to your heart or
your childs heart with a stethoscope to find out whether a murmur is
innocent or abnormal. He or she will listen to the loudness, location, and
timing of the murmur to classify and describe the sound. This will help your
doctor diagnose the cause of the murmur.
Your doctor also may:
- Ask about your medical and family histories.
- Do a complete physical exam. He or she will look
for signs of illness or physical problems. These may include blue coloring of
the skin and delayed growth and feeding problems (in infants).
- Ask about your symptoms, such as chest pain,
shortness of breath (especially with physical activity), dizziness, or
fainting.
Evaluating Heart Murmurs
When evaluating a heart murmur, your doctor pays
attention to many things, such as:
- How faint or loud the sound is. Your doctor will
grade the murmur on a scale of 1 to 6 (1 is very faint and 6 is very
loud).
- When the sound occurs in the cycle of the
heartbeat.
- Exactly where the sound is heard in the chest and
whether it also can be heard in the neck or back.
- Whether the sound has a high, medium, or low
pitch.
- How long the sound lasts.
- How breathing, physical activity, or change of
body position affects the sound.
Classifying Heart Murmurs
Doctors classify murmurs as systolic, diastolic, or
continuous.
A systolic murmur is heard when the heart is
squeezing and pumping blood out of the heart.
A diastolic murmur is heard when the heart is
relaxing and filling with blood. Diastolic murmurs often are a sign of a heart
defect or heart disease, and further checking is likely needed.
A continuous murmur is heard during the entire
heartbeat. These murmurs often are a sign of a heart defect or heart disease,
and further checking is likely needed.
Diagnostic Tests and Procedures
If your doctor suspects you or your child has an
abnormal heart murmur, he or she may order one or more of the following tests.
Chest X Ray
A
chest
x ray is a painless test that creates pictures of the structures inside
your chest, such as your heart and lungs. This test is done to find the cause
of symptoms, such as shortness of breath and chest pain.
EKG
An
EKG
(electrocardiogram) is a simple test that detects and records the electrical
activity of the heart. An EKG shows how fast the heart is beating, the
hearts rhythm (steady or irregular), and where in the body the heartbeat
is being recorded.
An EKG also records the strength and timing of
electrical signals as they pass through each part of the heart.
This test is used to detect and locate the source of
heart problems. The results from an EKG also may be used to rule out certain
heart problems.
Echocardiography
Echocardiography
(EK-o-kar-de-OG-ra-fee) is a painless test that uses sound waves to create
pictures of your heart. The test gives information about the size and shape of
your heart and how well your hearts chambers and valves are working.
The test also can find areas of heart muscle that
arent contracting normally due to poor blood flow or injury from a
previous
heart
attack.
There are several different types of
echocardiography, including stress echocardiography. This type is done both
before and after a cardiac stress test. During this test, you exercise or take
medicine (given by your doctor) to make your heart work hard and beat fast.
Stress echocardiography shows whether you have decreased blood flow to your
heart (a sign of
coronary
artery disease).
Cardiac Catheterization
If your doctor thinks that your or your childs
abnormal heart murmur is due to a heart problem, such as a congenital heart
defect, he or she may want you to have a procedure called
cardiac
catheterization (KATH-e-ter-i-ZA-shun).
For this procedure, a long, thin, flexible tube
called a catheter is put into a blood vessel in your arm, upper thigh (groin),
or neck and threaded to your heart. Through the catheter, your doctor can
perform diagnostic tests and treatments on your heart.
How Is a Heart Murmur Treated?
Innocent Heart Murmurs
Healthy children who have innocent heart murmurs
dont need treatment because they have normal hearts. If your child has an
innocent murmur, alert his or her doctor during regular checkups.
Pregnant women who have innocent heart murmurs due
to extra blood volume also dont need treatment.
You may have an innocent heart murmur due to an
illness or condition, such as
anemia,
hyperthyroidism, or fever. The murmur will go away once the illness or
condition is treated.
Abnormal Heart Murmurs
Treatment for abnormal heart murmurs depends on the
heart problems causing them. For example, treatment for a congenital heart
defect depends on the type and severity of the defect. Treatment may include
medicine or surgery. (For more information, see the Diseases and Conditions
Index Congenital
Heart Defects article.)
When an infection or disease causes a heart murmur,
treatment depends on the type, amount, and severity of the heart damage.
Treatments may include medicine or surgery.
Key Points
- A heart murmur is an extra or unusual sound heart
during a heartbeat. Murmurs range from very faint to very loud. They sometimes
sound like a whooshing or swishing noise.
- There are two types of heart murmurs: innocent
(harmless) and abnormal. A person who has an innocent murmur has a normal heart
and usually has no other signs or symptoms of a heart problem. Innocent murmurs
are common in healthy children. A person who has an abnormal murmur may have
other signs or symptoms of a heart problem.
- A heart murmur is not a disease, and most murmurs
are harmless. However, a murmur may be a sign of a heart problem, especially if
other signs or symptoms are present.
- Innocent heart murmurs are sounds heard when
blood flows through a normal heart. This may happen if blood flows faster than
normal through the heart or if theres extra blood flow through the heart.
Changes to the heart that result from
heart
surgery or aging also may cause some innocent heart murmurs.
- The most common cause of abnormal heart murmurs
in children is
congenital
heart defects. These are problems with the hearts structure that are
present at birth. Infections or other conditions that damage the heart valves
or other structures of the heart also may cause abnormal heart murmurs. Heart
murmurs due to these problems are more common in adults.
- Some people who have heart murmurs have signs and
symptoms of heart problems. These may include a blue coloring of the skin, poor
eating and abnormal growth (in infants), shortness of breath, excessive
sweating, chest pain, dizziness or fainting, and fatigue (feeling very
tired).
- Doctors use a stethoscope to listen to heart
sounds and hear heart murmurs. To diagnose a heart murmur, your doctor may do a
physical exam, ask about your medical and family histories, and ask about your
symptoms. If your doctor suspects that you or your child has an abnormal heart
murmur, he or she may order diagnostic tests.
- Many people who have innocent heart murmurs
dont need treatment. In some cases, an innocent heart murmur may be due
to an illness or condition. The murmur will go away once the illness or
condition is treated. Treatment for abnormal heart murmurs depends on the heart
problem causing them. Treatments may include medicine or surgery.
- Innocent heart murmurs dont cause symptoms
or require you to limit physical activity. Although an innocent murmur may be a
lifelong condition, your heart is normal and you likely dont need
treatment.
- If you have an abnormal heart murmur, the amount
and type of ongoing care and treatment you will need depends on how severe your
condition is. Talk to your doctor about the type of care you need.
Links to Other Information About Heart Murmurs
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
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