What is a murmur?

As a pediatric cardiologist, I often get asked, “What is a murmur?” Simply put, a murmur is only a heart sound occurring between the “lub and dub” sounds of the heart. More importantly, a murmur is not a hole or a heart defect.

The bigger question to me is if there is something abnormal with the heart that causes the heart murmur.  This is a pathologic, or abnormal, heart murmur or sound that is caused by a hole or a heart valve narrowing as well as a number of other problems. However, most murmurs are functional/ benign/ innocent. These “normal” heart murmurs are heard in many children. In fact, experienced pediatric cardiologists can hear heart murmurs in the majority of children. Furthermore, some of these “normal” heart murmurs can be heard for the first time in toddlers and older children. Many times these murmurs become less noticeable as we grow into adults. Whether or not this normal physical exam sound disappears as we get older it doesn’t matter because it doesn’t reflect anything abnormal with the heart.

Other points that can be confusing: some heart defects may not cause a murmur and some patients with normal heart murmurs can have a new and unrelated murmurs develop that are not normal, especially as we age into older adulthood. Furthermore, a “loud” murmur heart when a child is ill, is a common feature of normal heart murmurs.

Since murmurs are so common, I recommend your primary care doctor listen to the child’s heart during a well visit. If they are concerned about the heart sounds or other symptoms, then a pediatric cardiologist referral can be recommended. The pediatric cardiologist might feel comfortable that the murmur is normal without echocardiography. He might also opt to perform an echocardiogram to further evaluate the heart as even pediatric cardiologists aren’t perfect. If the murmur is determined to be normal then a follow up with the primary doctor is advised and return cardiology visits are indicated only if here is a new finding that is concerning.