When are murmurs cause for concern?
Why Are Heart Murmurs Common Among the Young?
A heart murmur is a sound produced by the flow of blood through the heart. According to University of Virginia pediatric cardiologist Anitha Jayakumar, MD, murmurs are commonly detected in babies within their first year of life simply due to the anatomy of a growing heart.
“A baby’s heart is about the size of a walnut and within it there are the four chambers, valves and two big arteries,” she says. “Babies have a fast heartbeat so there is rapid dynamic movement through this complex network with lots of angles, which often generates a sound.”
Typically, No Cause for Alarm
These benign, or innocent, murmurs have no underlying cause and often will dissipate as the child gets older; the heart grows larger so turbulence is reduced and more muscle, fat and tissue develop between the heart and chest wall, making the noise less audible.
Parents who discover their child has a murmur should ask the physician to distinguish between an innocent murmur and a pathological defect. Just by listening, some physicians can make this determination. “The murmur quality is different if there is a narrowing of the arteries, a hole in the heart or a leaky valve,” says Jayakumar.
Additional tests like an echocardiogram or EKG may be needed to confirm the cause of the murmur. If it is benign and there were no serious complications at birth, then there’s no need to take special precautions as the child ages, according to recent recommendations by the American Heart Association.
Certainty Comes from Screening
While a majority of serious heart problems are detected before a child is born, a few newborns with a serious heart defect will show no signs of being sick in the first few days of life. And 2 to 4 percent of these infants will be sent home from the hospital undiagnosed. A murmur can sometimes be a sign that a heart defect is present but often even this sign is absent.
Approximately 36,000 children in the United States are born with heart defects each year. To ensure early diagnosis of congenital heart disease (CHD), a new routine screening method has been implemented at UVA that makes detection simpler.
Pulse oximetry measures a baby’s blood oxygen levels by taping a probe to the infant’s hand and foot. “The oxygen saturation level should be the same in upper and lower extremities,” says Jayakumar. “If they are not the same, this signals a problem.”
Late Arrival of a Murmur
Occasionally, murmurs present at birth remain through adulthood. New or acquired murmurs may also develop gradually over time, often due to a heart muscle disorder or valve malfunction. “We may see kids in their teens with heart murmurs. They may be innocent murmurs that were overlooked or the murmur may be due to changes that happen slowly as heart function deteriorates,” says Jayakumar. These patients may have a racing heart or fatigue, but a majority have no other symptoms. “It’s a subtle finding sometimes,” adds Jayakumar.
While often insignificant, a heart murmur can sound the alarm that something is wrong. Fortunately, current technology and treatment has advanced enough to manage even serious heart conditions.
For more information about UVA’s pediatric heart services visit the UVA Children’s Heart Center.