Heart Murmurs and Your Child (continued)

It's not unusual for a murmur to be noticed during a check-up, even though no murmur was heard before. This is for several reasons. Innocent murmurs tend to come and go, depending on the child's heart rate, position during the exam, and the presence of fever. Some new murmurs may be a sign of a newly-developed heart problem. Finally, some heart problems present from birth (congenital heart problems) may not initially be severe enough to cause a murmur that can be detected during examination.

Because of the common misconception that all heart murmurs are serious, it's important for parents to understand which type of murmur their child has and if it needs further evaluation.

What's an Innocent Murmur?

The most common type of heart murmur is called functional or innocent. This diagnosis means the murmur is produced by a normal, healthy heart. It can come and go throughout childhood. It usually goes away on its own as the child gets older and doesn't pose any health threat.

Kids with innocent heart murmurs don't require a special diet, restriction of activities, or any other special treatment. They do not need to take a dose of antibiotic before going to the dentist. Those old enough to understand that they have a heart murmur should be reassured that they aren't any different from other kids. In other words, an innocent murmur is the sound of normal blood moving through a normal heart in a normal way. A simple analogy is that just as we can sometimes hear the sound of air moving in an air duct, or water flowing through a plumbing pipe, we can often hear the sound of blood moving through the heart even if there is not a heart problem.

What About Congenital Heart Defects?

Some murmurs may indicate a problem with the heart. If the doctor suspects something other than an innocent heart murmur, your child will see a pediatric cardiologist, who may order or perform additional tests such as a chest X-ray, an EKG (an electrocardiogram), or an echocardiogram. An echocardiogram, or "echo," is an ultrasound picture of the heart structures (chambers, walls, and valves). It records the motion of the blood through the heart and can measure the direction and speed of blood flow within the heart structures.

About 1 out of every 100 babies is born with a structural heart problem, or congenital heart defect. These babies may show signs of their defect as early as the first few days of life, or they may appear completely healthy until later in childhood. Some kids won't show any symptoms beyond a heart murmur, while others will have symptoms that could be mistaken for other illnesses or disorders.

Symptoms of a significant heart defect in newborns and infants can include:

• rapid breathing
• difficulty feeding
• blueness in the lips (called cyanosis)
• failure to thrive

Symptoms in an older child or adolescent may be:

• fatigue
• difficulty exercising or doing physical activity
• chest pain

Contact your doctor if you notice any of these symptoms.

Congenital heart defects can be seen in chromosomal disorders such as trisomy 21 (Down syndrome), or associated with specific gene abnormalities. Babies with other birth defects may also have heart defects. Exposure to certain chemicals, including alcohol, or medications before birth can be associated with congenital heart disease. While some parents may have more than one child with a heart defect, most heart defects aren't considered to be hereditary. In most cases, however, children with congenital heart defects have no known risk factors.