A murmur is the sound of blood flowing through the heart and the largeblood vessels that carry the blood through the body. Murmurs can be a sign of a congenital (from birth) heart defect or can provide clues to illnesses that start elsewhere in the body and make the heart work harder, such as anemia or fever. In children, murmurs are often harmless and are just the sound of a heart working normally. These harmless murmurs are often called innocent or functional murmurs. Murmurs are easily heard in children because they have thin chests and the heart is closer to the stethoscope. When children have fevers or are scared, their hearts beat faster and murmurs can become even louder than usual.
Still murmur is usually heard at the left side of the sternum (breastbone), in line with the nipple. This murmur is harder to hear when a child is sitting or lying on his or her stomach.
Pulmonic murmur is heard as blood flows into the pulmonary artery (artery of the lungs). It is best heard between the first 2 ribs on the left side of the sternum.
Venous hum is heard as blood flows into the jugular veins, the large veins in the neck. It is heard best above the clavicles (collarbones). Making a child look down or sideways can decrease the murmur.
They are found in children aged 3 to 7 years.
The intensity of the murmur can change with the child's position or breathing.
They are usually heard in one spot on the chest or above the clavicles and do not move (radiate) to other areas like the armpits, back, or higher in the neck.
These murmurs are heard when the heart is normal and do not cause harm or increase risk of other health problems.
No special precautions are needed and no restrictions are placed on activity.
As a child grows older, the murmur may lessen and eventually disappear, but it does not matter if the murmur remains.
Children with innocent murmurs do not need specific follow-up or diagnostic studies.
Children with a murmur may be referred to a pediatric cardiologist if
there is a family history of sudden death.
the child has had chest pain with exercise, palpitations (a sensation of rapid heartbeat), or syncope (fainting spells).
the child has a history of poor growth, is easily tired, or cannot keep up with peers while playing.
the murmur does not follow the pattern of an innocent murmur.
the child has trouble breathing or cyanosis (a bluish discoloration of the fingers or lips), indicating low levels of oxygen in the blood.
there is edema (swelling of legs and feet) and enlargement of the liver (hepatomegaly).
American Academy of Pediatrics Healthy Children www.healthychildren.org/English/health-issues/conditions/heart/Pages/Heart-Murmur.aspx
National Heart, Lung, and Blood Institute www.nhlbi.nih.gov/health/health -topics/topics/heartmurmur
To find this and previous JAMA Patient Pages, go to the Patient Page link on JAMA 's website at www.jama.com. Many are available in English and Spanish.
Sources: American Academy of Pediatrics; National Heart, Lung, and Blood Institute
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Topic: PEDIATRIC HEART HEALTH
Punnoose AR, Burke AE, Golub RM. Innocent (Harmless) Heart Murmurs in Children. JAMA. 2012;308(3):305. doi:10.1001/jama.2012.6223