You heard a what?! The truth about heart murmurs

Have you ever put your finger over the end of a water hose while the water was turned on? When you do that, you see the water spray and hear a shhhhhhhhhh type of noise that wasn’t there before. The sound you hear is the sound of the water swishing around and speeding past your finger. You’ve created turbulence in the water. The same principle applies to blood as it flows through the heart – if there is turbulent flow (swishing of blood), it will make a noise. That shh shh shh can be heard through the stethoscope with each heartbeat. We call that a murmur. Murmurs can also be caused by vibration of tissue within the heart and there are other murmurs that we’re not even sure how the noise is generated.

If you are told your child has a murmur, the most important thing is to remain calm. You’re not alone – far from it. Lots and lots of kids have murmurs. In fact, about half of kids (or more) will have a murmur at some point in childhood. The most common age is 3 or 4 years old. “Innocent murmurs” are those that a doctor can hear, but are not associated with any heart disease. “Pathologic murmurs” are murmurs associated with a true heart abnormality. A ventricular septal defect or VSD is a hole between the bottom chambers of the heart that causes a pathologic murmur. Innocent murmurs usually come and go and then eventually go away as the child grows up. They can come out when the child is sick,has a fever or is dehydrated. Pathologic murmurs will be present as long as the heart problem exists.

So how do we know the difference? While it is not an exact science, with practice, health care professionals can discern most innocent murmurs from pathologic ones. There are differences in the location of the murmur on the child’s chest, pitch, volume, duration and timing of the murmur. Whether the murmur comes when the heart is squeezing or relaxing is another clue. We also take the age of the patient and position of the patient (lying, sitting or standing) into account when deciding if a murmur is innocent or pathologic.

A murmur is not a disease and it is not an indication that your child needs heart surgery. Most kids with murmurs have healthy, normal hearts. Many murmurs can be followed by a pediatrician or nurse practitioner without referral to a cardiologist. If your child’s primary care provider has concerns, the patient may be sent to a pediatric cardiologist where the exam will be repeated. Sometimes, further testing, like an echocardiogram (ultrasound of the heart), will be performed. Other times, after discussing any symptoms or concerns you have, the cardiologist will simply provide reassurance that the murmur sounds innocent and more testing is unnecessary.

So, the next time you hear the term, “murmur,” just remember the water hose example. Specialty care is not always required. The majority of murmurs in children are innocent sounds that go away with time. If referral is felt to be necessary, a pediatric cardiologist will be able to address any concerns that you may have.