Heart murmurs are common in children and are casued by turbulent blod flow. As a presenting sign they are usually heard during a routine examination or during an intercurrent infection.
When heard during the the neonatal examination they are most frequently due to a closing patent ductus arteriosus or to mild stenosis at the origin of the left pulmonary. Aortic or pulmonary stenosis (including that associated with tetralogy of Fallot) may also present in this way.
In the older child most murmurs are "innocent" and if they exhibit all the clinical characteristics then further investigation is unnecessary.
Site maximum intensity
Loudness - scale ranges from 1 to 6 (4/6 have a thrill)
Timing systolic (ejection, mid or pansystolic) diastolic (early or mid) continuous
Family history common
Asymptomatic & the murmur is only abnormal cardiac finding
Systolic (flow murmur) or continuous (venous hum) - never diastolic
Flow murmurs (Still’s*) are louder when lying & quieten on sitting
Venous hums louder when standing & disappear on lying
*Sir George Frederick Still 1868-1941. English Paediatrician