Are Innocent Heart Murmurs in Kids a Cause for Concern?

Whether your child is getting a routine checkup, a sports physical or a back-to-school exam, your pediatrician listens to make sure the heart sounds healthy.

The American Academy of Pediatrics (AAP) describes a normal heartbeat as “lub-dub, lub-dub, lub-dub.” Sometimes, a doctor may hear an extra sound called a heart murmur.

Dr. Ginnie Abarbanell, a pediatric cardiologist with the University Health Cardiovascular Center, explains what parents and caregivers should know about heart murmurs, including when they may affect sports or other activities.

What Is a Heart Murmur?

The heart has four chambers that pump blood through the body. A heartbeat is the sound of those chambers opening and closing.

A heart murmur is an extra sound within a heartbeat. “Typically, a murmur sounds like a blowing, whooshing or rasping noise,” said Dr. Abarbanell. “This sound happens because of the way blood moves through the heart valves.”

Heart murmurs are common in children. Most are innocent or harmless.

There are two types of heart murmurs in kids:

• Innocent heart murmurs: As the name indicates, these murmurs are not dangerous. They are heart defects that happen when blood flows normally through the heart or nearby blood vessels.
• Pathologic heart murmurs: These are also called abnormal heart murmurs. They happen because of an underlying heart problem. Some are present at birth, while others develop later.

Innocent heart murmurs are sometimes called functional heart murmurs because they happen while the heart is working normally.

Are Heart Murmurs in Children and Newborns Normal?

Most heart murmurs in children are normal. These are the innocent heart murmurs mentioned above. According to the AAP, more than two-thirds of school-aged children may have an innocent heart murmur at some point.

“Doctors often find these murmurs during regular exams,” explained Dr. Abarbanell.
“They may sound louder when a child is sick, excited or nervous. These feelings are common at a doctor’s visit.”

Some heart murmurs can be a sign of a more serious heart condition. Because of this, your child’s pediatrician may recommend a visit with a pediatric cardiologist. A cardiologist can help determine whether the murmur is serious. 

Causes & Risk Factors of Heart Murmurs

Pathologic heart murmurs can have many causes, including:

• Hypertrophic cardiomyopathy, which is when the heart muscle becomes too thick
• Regurgitation, which is when a heart valve does not close all the way
• Stenosis, which is when a heart valve opening is smaller than normal
• Holes in the heart, such as ventricular septal defects and atrial septal defects

Many conditions that cause pathologic heart murmurs in children are congenital heart defects. This means they are present at birth. Conditions may include atrial septal defect, patent ductus arteriosus and ventricular septal defect. Other heart problems can develop later in life.

Wondering if your child is at higher risk? Research shows children may have a higher risk of heart murmurs if they have:

• Conditions that make the heart pump faster, such as hyperthyroidism, anemia or thiamine deficiency
• Down syndrome or certain other genetic conditions
• Exposure to certain medicines or alcohol during pregnancy
• A family history of heart disease or other heart problems
• Rheumatic fever

Children may also have a higher risk of heart disease if their birth parent had uncontrolled gestational diabetes during pregnancy. Researchers think high blood sugar may affect how the heart develops.

Can an Innocent Heart Murmur Become Serious if Left Untreated?

An innocent heart murmur cannot progress to a pathological one. It also will not get worse or become more serious.

Innocent heart murmurs do not need treatment since the heart is normal. They usually go away on their own by adulthood.

Diagnosing Heart Murmurs & Next Steps

Doctors can find innocent heart murmurs by listening to the heart with a stethoscope. If your child’s pediatrician thinks your child has an innocent heart murmur, they may refer you to a pediatric cardiologist to confirm it.

The cardiologist will ask about your child’s health and family health history. They may also order tests to see how well the heart is working, such as:

• Chest X-ray
• Echocardiogram (ECHO)
• Electrocardiogram (EKG)

If the tests show the murmur is innocent, your child may not need a follow-up visit. If the tests find a heart or blood vessel problem, your child may need more testing or treatment.

If Your Child Has a Heart Murmur

If your child is diagnosed with an innocent heart murmur, try not to worry. There is nothing wrong with your child’s heart. Your child will not need medicine, a special diet or activity limits.

If your child has a pathologic heart murmur, know that these murmurs are rarely life-threatening. Most pathologic heart murmurs in kids are caused by a minor heart defect. Some may not need treatment. A cardiologist can help you decide the best next steps for your child.

Can Kids With Heart Murmurs Play Sports?

Most children with an innocent heart murmur can safely play sports and take part in other physical activities.

“An innocent heart murmur means the heart is normal,” said Dr. Abarbanell. “These children can usually stay active like other kids.”

If your child’s provider thinks the murmur may be pathologic or related to another heart condition, they may recommend more testing before your child is cleared for sports. This can help show whether treatment or activity limits are needed.

Children’s Cardiology at University Health

When your child’s heart is at stake, you want expert care. You can find that care at University Health’s Pediatric Congenital Heart Center, the only dedicated pediatric heart center in South Texas.

We offer complete care for heart conditions in children. This includes diagnosis, treatment and long-term care. Learn more about the conditions we treat.