Heart murmurs are abnormal sounds during your heartbeat cycle — such as whooshing or swishing — made by turbulent blood in or near your heart. These sounds can be heard with a stethoscope. A normal heartbeat makes two sounds like "lubb-dupp" (sometimes described as "lub-DUP"), which are the sounds of your heart valves closing.
Heart murmurs can be present at birth (congenital) or develop later in life. A heart murmur isn't a disease — but murmurs may indicate an underlying heart problem.
Most heart murmurs are harmless (innocent) and don't need treatment. Some heart murmurs may require follow-up tests to be sure the murmur isn't caused by a serious underlying heart condition. Treatment, if needed, is directed at the cause of your heart murmurs.