A heart murmur is an extra sound heard during a heartbeat that is caused by turbulence in blood flow through the heart. Most heart murmurs are innocent, which means they do not cause health problems and may disappear with age. But some heart murmurs require medical treatment because they are a sign of a problem in the heart’s walls, lining, or valves, or are indications of other diseases or conditions.
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Jill’s baby wiggled as the doctor placed a stethoscope on his chest to listen to the heartbeat. Jill smiled, because she knew how cold the device could feel on bare skin. But Jill became concerned when the doctor reported hearing a heart murmur. The sounds of the heartbeat usually are described as a “lub” followed by a brief pause and then a “dub.” Jills doctor, however, heard another sound, like a faint rush of water in a pipe.
The sound of a heart murmur may occur as the heart is filling with blood or as it is contracting to send blood to other parts of the body. Sometimes the murmur means there is a defect in the heart or in one of its valves. But many times doctors also find “innocent” heart murmurs, which do not require any special treatment. Innocent murmurs are common in babies and children. The murmurs often disappear as a child gets older, and they are not a sign of heart disease. Fortunately, Jill’s baby had an innocent heart murmur. The heart is healthy, but there is a faint murmur during heartbeats.
Heart murmurs, however, also can be caused when one or more of the heart s four valves is operating abnormally. Sometimes the valves do not close completely, which may allow blood to leak back from one chamber to another when it should not. Valves also might not open completely, which causes blood to rush through a smaller opening than normal. The murmur also can result from a hole, usually in the wall between the left and right sides of the heart.
Some people are born with valve defects or with holes that cause heart murmurs. Others develop a heart murmur after bouts with endocarditis* or rheumatic fever*. Both of these infections may damage heart valves. Anemia and other medical conditions may result in murmurs, even when the valves are perfectly normal.
- * endocarditis
- (en-do-kar-DY-tis) refers to inflammation of the lining of the heart, or endocardium (en-do-KAR-de-um), usually after an infection settles in a heart valve or in the heart lining.
- * rheumatic fever
- is a disease that causes fever, joint pain, and inflammation affecting many parts of the body. It varies in severity and duration, and it may be followed by heart or kidney disease.
A doctor listens to a patient s heart as part of the physical exam. That is how murmurs usually are detected. Certain defects cause
particular sounds, which help doctors make their diagnosis. For example, if a valve fails to close properly between the upper and lower chambers on the heart’s left side, doctors may hear a distinctive murmur that will aid in diagnosing the problem.
These sounds come from the heart’s valves “shutting” on the blood inside the heart. The “lub” happens when the blood reaches the mitral and tricuspid valves. The “dub” happens when the blood hits the aortic and pulmonary valves.
Doctors also can use an echocardiogram to examine the heart and determine a murmur’s cause. This test is done with a device that uses sound waves to create an image of the heart. It is similar to the ultrasound machine that creates images of unborn babies inside pregnant women.
If the murmur is innocent, nothing special needs to be done. People with innocent heart murmurs can play sports, eat the same foods, and do all the same things as their schoolmates.
Murmurs that indicate valve disease may need to be treated with medication or surgery. Such surgery may involve either replacing the valves or closing the hole. Although it is important to find and treat those murmurs caused by valve abnormalities or other medical conditions, most murmurs detected during childhood or adolescence are innocent.
The U.S. National Heart, Lung, and Blood Institute posts a fact sheet about heart murmurs at its website. http://www.nhlbi.nih.gov/nhlbi/infcentr/topics/hrtmurm.htm
American Heart Association National Center, 7272 Greenville Avenue, Dallas, TX 75231. The American Heart Association posts fact sheets about heart murmurs and about how the heart works at its website. Telephone 1-800-AHA-USA1
A heart murmur is an abnormal extra sound made when the heart beats. The sound is produced by blood moving through the heart and its valves.
Heart Murmur: Words to Know
- Atrium (plural: atria):
- One of the two upper chambers of the heart.
- A test that uses sound waves to produce an image of the inside of the heart.
- A test that measures the electrical activity of the heart to determine whether it is functioning normally.
- One of the two lower chambers of the heart.
Blood flows from the body into the heart through veins. It moves from one side of the heart (the atria) into the other side of the heart (the ventricles). It then flows out of the heart through arteries. The flow of blood is controlled by muscular flaps called valves. The valves open and close as blood flows through each part of the heart. When the valves between the atria and the ventricles close, they make a "lubb" sound. When the valves between the ventricles and the major arteries close, they make a "dubb" sound. When doctors listen to the heart beat of a healthy person, they hear a "lubb-dubb" sound.
A heart murmur is a sound other than the usual "lubb-dubb" sound produced by the heart. It usually lasts longer than a normal heart sound and can be heard between the normal "lubb-dubb" sounds.
Heart murmurs occur in normal hearts. They are especially common among young children. Harmless heart murmurs are known as innocent heart murmurs. Innocent heart murmurs are usually very faint. They come and go in an irregular pattern. They do not pose a health threat to the person in whom they occur.
Other heart murmurs are more dangerous. They are called pathological heart murmurs. One cause of pathological heart murmurs is a damaged heart valve. Pathological heart murmurs may be an indication of a serious heart problem. The sound they make is louder and more continuous than that of an innocent heart murmur. They are sometimes described as a clicking or galloping sound.
Innocent heart murmurs are caused by the normal sound of blood flowing through the heart and its blood vessels. They may also be caused by emotions, such as stress or fear, or by health problems, such as fever or anemia (see anemia entry).
Pathological heart murmurs are usually caused by one of two problems. One of these problems is a defective heart valve. The valve may not close or open completely. When that happens, blood does not flow normally through the heart. Enough blood may not be able to get through the heart, or the blood may back up and go the wrong direction.
The other problem is a hole in the heart. A hole sometimes develops in the wall between the left and right sides of the heart. A hole of this kind may be relatively harmless, or it may cause heart problems that require surgery.
Innocent heart murmurs usually have no symptoms. They have no effect on the way the heart functions. Murmurs caused by defects in the heart do have symptoms. Those symptoms include shortness of breath, dizziness, chest pains, palpitations (a feeling that the heart is beating faster or less regular than normal), and congestion of the lungs.
Heart murmurs can usually be detected quite easily. A doctor listens to a patient's chest with a stethoscope. Any sounds other than the normal "lubb-dubb" beating of the heart can be heard. If the sounds are faint, they may indicate an innocent heart murmur. An innocent heart murmur usually requires no further treatment.
One exception involves faint heart murmurs that occur in infants and children with other symptoms. Those symptoms in infants include poor appetite, problems with breathing normally, and failure to develop normally. In older children, symptoms include loss of consciousness or inability to take part in normal exercise.
The presence of a loud heart murmur may lead to further tests. A chest X ray, for example, may show the presence of defects in the heart. An electrocardiogram (ECG, pronounced ih-LEK-tro-KAR-dee-o-gram) shows whether the heart is beating normally. An electrocardiogram is a test in which the electrical activity of the heart is recorded.
An echocardiogram (pronounced ekko-KAR-dee-o-gram) may also be used to diagnose heart murmur. An echocardiogram is a test in which sound waves are sent through the heart. The path taken by the sound waves is recorded. The pattern of reflected sound may show any defects in the heart.
Innocent heart murmurs require no treatment. Pathological heart murmurs may also require no treatment unless they are serious. In that case, surgery may be required to correct the heart defect such as defective valves or holes in the heart.
Most children with innocent heart murmurs outgrow them by the time they reach adulthood. Severe cases of pathological heart murmurs may require surgery. If surgery is not successful, murmurs may develop into more serious heart problems that, in relatively rare cases, may lead to death.
There is no known method for preventing heart murmurs.
FOR MORE INFORMATION
"Heart Murmurs in Infants: Not Always Cause for Alarm." Mayo Health Oasis. (February 26, 1998) [Online] http://www.mayohealth.org (accessed on March 4, 1998).
"When Your Child's Doctor Hears a Heart Murmur." Children's National Medical Center 1998. [Online] http://www.cnmc.org/heart.htm (accessed on March 6, 1998).