Heart murmur
The familiar 'lub-dub' sound of the heartbeat is caused by the rhythmic closing of the heart valves as blood is pumped in and out of the chambers. A heart murmur is a sound caused by blood flow within the heart. Instead of 'lub-dub', the heartbeat may have an added sound like a hum, a whoosh or a rasp. The cause of the whooshing sound is the vibration of blood as it moves through the heart, which is normally undetectable by stethoscope.
Blood can flow abnormally through the heart for many reasons including defective valves, congenital heart disorders and anaemia. A 'noisy' heart isn't always a sign of disease or malfunction. Many children have 'innocent' heart murmurs that don't require any treatment or observation. However, medical tests are often needed to distinguish between a harmful heart murmur and an innocent one, as they can sound the same through a stethoscope.
Symptoms
Heart murmurs are themselves often asymptomatic (have no symptoms). Commonly, they are innocent and are only detected during a routine medical examination.
Abnormal heart murmurs may be associated with various types of heart disease, particularly those affecting the heart valves.