Heart Murmurs in Children

Heart murmurs can be heard in normal people and, in fact, most children referred to a pediatric cardiologist for evaluation of a heart murmur have normal hearts.

Although the name is unsettling, heart murmurs are common in childhood and usually the normal sound of a healthy child’s heart.

What is a heart murmur?

A heart murmur is a sound that is heard when listening to the heart with a stethoscope. Heart murmurs can be heard in normal people and, in fact, most children referred to a pediatric cardiologist for evaluation of a heart murmur have normal hearts. However, because a heart murmur may be produced by heart abnormalities such as a narrow or leaking valve, or a hole in a wall between high- and low-pressure chambers, if the pediatrician is unsure that the murmur sounds normal, they may refer the child to a pediatric cardiologist for further evaluation.

Why are heart murmurs heard in normal people?

A heart murmur is a type of heart sound heard with the stethoscope; it is not a diagnosis. All sound is due to vibration. When you hear someone talk, it is because their vocal cords are vibrating the air which travels to your eardrum to stimulate a nerve that brings the sound to your brain.

The heart is a very active set of pumps with one-way valves that open and close at the entrance and exit of each pumping chamber; it is a noisy organ and heart valve closures with each beat produce the familiar “lub dub” heart sounds heard in everyone. The muscle in the walls of the pumping chamber squeeze the blood rapidly into the pipes. This rapid ejection causes the heart and great arteries to vibrate and these drawn out vibrations produce the noise we call a murmur. 

All normal people make these vibrations, so we all have heart murmurs. However, the older we are, the slower our hearts beat and the softer our murmurs so that, in most cases, the soft murmurs cannot be heard by the time sound reaches the chest wall.  Infants and children who have much more active hearts and thinner chest walls tend to have easily heard heart murmurs. Also, just like each face is different, the shape of each heart chamber is slightly different and produces sounds of a different pitch so that some people, even in adulthood, may have easily heard, “innocent” heart murmurs while some infants and children do not make murmurs loud enough to be heard with the stethoscope.

Why do some of the doctors hear the murmur and others not?

Characteristically, “innocent” heart murmurs are variable depending on the cardiac output (your heart will beat harder if you’re scared in the doctor’s office), your position while being examined, and the overall noise level in the office when the doctor is listening to the heart. Conversely, abnormal (“pathological”) heart murmurs are often harsher and louder sounding so they are heard at every visit.

What does it mean if my child has an “innocent” murmur?

It means that their heart evaluation was normal and that the murmur is just the “song” of their normal heart. I often tell parents that their child with an “innocent” murmur who has undergone a comprehensive cardiac evaluation is more certainly normal than their siblings or friends whose hearts we are assuming to be normal because their history and physical examination are normal.

Does my child with an “innocent” murmur need cardiac follow up?

No. Having a diagnosis of “innocent” murmur means that your doctor has judged the heart to be normal. A normal heart with an easily heard murmur is no less normal than a quiet heart. You can think of it like hair color. A child with brown hair is no less normal than one with blond hair and neither require follow up for their normal hair.  Unless a different murmur is heard by the pediatrician that suggests a heart abnormality, no follow up is necessary.

What if the murmur is not innocent?

If the cardiologist determines that there is a problem causing the murmur, they will explain it in detail. There are many simple and mild heart abnormalities that cause murmurs and that do not need treatment but each case will have its own diagnosis and plan explained by the cardiologist.

Dr. Parness is a recognized expert in the field of pediatric cardiology, with over 40 years of experience at top hospital programs across the Northeast. He currently provides onsite cardiology services at RefuahHealth’s Main Street location. He is also the acting Director of Pediatric Echocardiography at Cohen Children’s Medical Center/Northwell and Professor of Pediatrics at the Zucker School of Medicine at Hofstra/Northwell.

For more information call 845.354.9300.