Synopsis
Distinguish common flow murmurs from structural heart disease, identify the newborn or child needing urgent cardiac assessment, and explain when echocardiography and follow-up are required.
- An innocent murmur occurs in a structurally normal heart and reflects audible flow; it is common in childhood and may become louder with fever, anaemia, anxiety or increased cardiac output.
- A typical innocent murmur is short, systolic, grade 1–2, localised, without a thrill, and changes with posture; the child has normal pulses, heart sounds, saturation, growth and exercise tolerance.
- Pathological clues include symptoms, neonatal age, cyanosis, abnormal femoral pulses, diastolic or pansystolic timing, a thrill or click, grade 3 or louder intensity, abnormal S2, or fixed radiation.
- Initial assessment must include gestation and age, antenatal findings, feeding and growth, exercise symptoms, infections, family cardiac history, saturation, brachial and femoral pulses, perfusion, liver and a complete cardiovascular examination.
- A newborn with a murmur needs a defined neonatal pathway even when well because ductal closure can reveal obstruction after discharge; urgency is determined by saturation, pulses, symptoms and murmur features.
- Echocardiography is the definitive anatomical test when structural disease is suspected. ECG and chest radiography may describe consequences but cannot reliably prove a murmur innocent.
- Do not request echocardiography indiscriminately for a confidently identified innocent murmur in an asymptomatic older child with a completely normal examination; refer when diagnostic confidence is incomplete.
- Urgent same-day cardiology discussion is required for cyanosis, shock, abnormal saturation or pulses, heart failure, a clearly pathological murmur or an abnormal ECG with concerning symptoms.
- An innocent murmur needs explanation and usually no activity restriction, medicine, dental antibiotic prophylaxis or routine review; families should return if symptoms or exercise limitation develop.
- A structural diagnosis changes follow-up: record the precise lesion, haemodynamic importance, intervention plan, exercise advice, endocarditis advice and which team owns surveillance.
Key red flags
Central cyanosis, persistent low saturation, respiratory distress, shock, metabolic acidosis or poor responsiveness demands same-day emergency assessment rather than an outpatient murmur referral.
Absent, weak or delayed femoral pulses, an arm-leg blood-pressure difference, cool lower limbs or neonatal collapse raises coarctation or interrupted aortic arch.
Feeding breathlessness, sweating, prolonged feeds, faltering growth, recurrent chest infection, hepatomegaly or oedema suggests a haemodynamically important lesion.
A diastolic, continuous, pansystolic, harsh grade 3 or louder murmur, thrill, click, abnormal second sound or murmur radiating widely is pathological until assessed.
Syncope during exercise, exertional chest pain, sustained palpitations or a family history of sudden unexplained death or inherited cardiac disease needs urgent specialist evaluation.
A normal newborn pulse-oximetry result or absence of a murmur does not exclude coarctation, total anomalous pulmonary venous drainage or another critical lesion.
Investigation priorities
Determine physiological stability and whether the sound fits a benign flow pattern.
Management branches
The murmur accompanies cyanosis, shock, respiratory failure, acidosis or abnormal femoral pulses.
- Begin ABCDE resuscitation with monitoring, glucose, blood gas and vascular access while summoning senior help.
- Obtain preductal and postductal saturations and focused pulses without delaying breathing or circulation support.
- Discuss immediately with paediatric cardiology and the retrieval network; use prostaglandin only through the duct-dependent lesion protocol.
The child is stable but has symptoms, abnormal pulses or saturation, a pathological murmur or inherited-risk features.
- Document the full phenotype, ECG when indicated and exact family history rather than referring for a murmur alone.
- Arrange same-day or expedited paediatric assessment according to symptom severity, age and local cardiac pathway.
- Give clear deterioration advice covering breathing, colour, feeding, perfusion, collapse and exercise symptoms.