Heart murmurs are extra sounds that can be heard through a stethoscope when listening to the heart.
Normally, a heartbeat makes a 'lub-dub' sound. The 'lub' is the sound made when the first set of valves in the heart close and the 'dub' is the sound of the second set of valves closing. Sometimes extra sounds can be heard when blood passes through the valves.
Heart murmurs can be detected during pregnancy by an ultrasound scan or they may be noticed during examination of the newborn. Sometimes it can be years before a heart condition is discovered.
Heart murmurs are extremely common in children with as many as eight out of ten children having some sort of extra heart sounds at some point. Fortunately, the majority of the time, heart murmurs are completely harmless and have no effect on the child's health.
However, in some cases a heart murmur signifies a problem with the heart. If a baby is born with a heart defect it is known as a congenital heart defect and this occurs in about one in 145 births.
Heart conditions arise if there is a problem with the structure of the heart chambers, walls, valves or blood vessels. For example there may be:
An opening in the walls separating the chambers of the heart which allows blood to flow in the wrong direction
Narrowing of the heart valves meaning bloodflow through the valves is reduced
Narrowing of the main artery out of the heart
Blockages in the vessels connecting the heart and the lungs
Abnormal connections between the chambers and vessels of the heart.
About half the time, congenital heart defects don't pose much of a problem as they can either be corrected with surgery or they won't need treatment at all.
Babies with more serious heart defects will probably need surgery after birth and possibly another operation when they are older. Most babies who have surgery for heart defects make a complete recovery.