A heart murmur is an extra or unusual sound heard during a heartbeat. Murmurs range from very faint to very loud. They sometimes sound like a whooshing or swishing noise. Normal heartbeats make a "lub-DUPP" or "lub-DUB" sound. This is the sound of the heart valves closing as blood moves through the heart. Doctors can hear these sounds and heart murmurs using a stethoscope. Overview There are two types of heart murmurs: innocent (harmless) and abnormal. People who have innocent heart murmurs have normal hearts. They usually have no other signs or symptoms of heart problems. Innocent murmurs are common in healthy children. Many, if not most, children will have heart murmurs heard by their doctors at some time in their lives. People who have abnormal murmurs may have other signs or symptoms of heart problems. Most abnormal murmurs in children are due to congenital heart defects. These are heart defects that are present at birth. In adults, abnormal murmurs are most often due to heart valve problems caused by infection, disease, or aging. Outlook A heart murmur isn't a disease, and most murmurs are harmless. Innocent murmurs don't cause symptoms or require you to limit physical activity. Although an innocent murmur may be a lifelong condition, your heart is normal and you likely won't need treatment. The outlook and treatment for abnormal heart murmurs depends on the type and severity of the heart problem causing them.