A heart murmur is an abnormal, extra sound during the heartbeat cycle made by blood moving through the heart and its valves. It is detected by the doctor's examination using a stethoscope.

A heart beating normally makes two sounds: "lubb" when the valves in one part of the heart close, and "dupp" when other valves close. A heart murmur is a series of vibratory sounds made by turbulent blood flow. The sounds last longer than normal heart sounds and can be heard between the normal sounds of the heart.

Heart murmurs are common in children, but they can also result from heart or valve defects. Nearly two thirds of heart murmurs in children are produced by a normal heart and are harmless. This type of heart murmur is usually called an "innocent" murmur. Innocent heart murmurs are typically very faint, intermittent, and occur in a small...