A heart murmur is a condition in which an audible whooshing or swirling sound is heard by your doctor while listening to your child’s heartbeat. In an ideal scenario, we don’t hear anything except the strong dull snapping of the classic “lub-dub, lub-dub, lub-dub”. The “lub” portion, also called S₁ or systole, is caused by the abrupt closure of mitral and tricuspid valves at the start of systole. The “dub” portion of the heartbeat is caused by the closing of the 2 semi-lunar valves in diastole.

To put it simply, when a murmur is identified, it means that your child’s doctor is hearing an unusual sound in between heartbeats. I would describe this sound like a “whooshing” or a “swishing” sound in most cases. Over 66% of all children (and 75% of all newborns) are actually born with heart murmurs and most of them are harmless or “innocent”.

Two of the most common types of heart murmurs are:

1. An atrial septal defect (or ASD). This is when a small hole between the top two chambers of a child’s heart is a little slow to close—don’t worry, it’s supposed to be open until they’re born. If your child has this type of murmur, their doctor may hear that small “whooshing” sound mentioned above. This sound, also known as turbulent flow, comes from your child’s blood traveling between the two sides of the heart through this tiny hole. If your pediatrician suspects turbulent flow, they may send you to a heart doctor just to have everything double checked but this condition usually resolves on its own with time.
2. Still’s Murmur, which is heard loudest when a child is laying down, can increase during times of high output—think fever or exercise—but the murmer’s root cause is still unclear. In most cases, this murmur disappears by adolescence.

Children with functional heart murmurs such as these do not typically have to alter their diet or other lifestyle choices. If no complications or symptoms arise, a pediatrician can simply check their heartbeat during their annual well checks and listen for the murmur (or the lack thereof).

Now, there are murmurs that may be more concerning. For example, loud or harsh-sounding murmurs need to be evaluated by a Pediatric Cardiologist—especially when paired with symptoms. If you notice any of the following (or hear your child complain of any of the following) you should consult your pediatrician immediately…

• • Shortness of breath
  • Sweating
  • Chest pain
  • Extreme fatigue
  • Blue hands, feet, or lips
  • Passing out

Murmurs by and large are extremely common in children and usually resolve with time. Very rarely do they end up needing surgical intervention or further medical workup if your child is healthy and developing normally. That said, every child is different, so don’t hesitate to ask your child’s provider any questions you may have regarding heart murmurs.

Until next time,

Will Robinson

Parkside Provider, unashamed Star Wars nerd, and fly-fisher for life