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Murmurs in Childhood

Written 8th April 2020 - Last Update 20th July 2026

Murmurs in Childhood

The regional hub for paediatric heart murmurs. Roughly ⅓–¾ of children will have an innocent murmur at some point between ages 1–14 — <1% of murmurs reflect underlying congenital heart disease. See also 6-week check and the individual congenital lesion pages below.

A murmur in an infant <12 months old needs further assessment — the risk of structural heart disease is much higher at this age. It’s reasonable to reassess at the next visit if the infant is otherwise thriving.

Diagnosing an innocent murmur (>12 months)

All four criteria must be met:

  1. No other abnormal physical findings.
  2. The child is asymptomatic — no dyspnoea, palpitations, fatigue, nausea/ vomiting, or cough.
  3. No risk factors for structural heart disease: family history of congenital heart disease, cardiomyopathy, or sudden unexpected death; gestational diabetes; maternal alcohol use in pregnancy; previous Kawasaki disease; rheumatic fever; genetic disorders; prematurity.
  4. No concerning features on auscultation — the 7 S’s.

The 7 S’s of an innocent murmur: Sensitive (changes with positioning/respiration) · Short · Single sound (no clicks or gallop rhythm) · Small (localised, non-radiating) · Soft · Sweet (not harsh) · Systolic (never diastolic).

Cardiac history red flags

Respiratory distress at rest (or with feeds, in infants) and reduced exercise tolerance; poor growth; central cyanosis; exertional syncope; family history of congenital heart disease, cardiomyopathy, or sudden unexpected death.

Examination

Vital signs (heart rate, respiratory rate, SpO₂), four-limb blood pressure (screens for coarctation), and femoral + brachial pulse volume/ symmetry are core parts of the paediatric cardiac exam, alongside auscultation itself.

Investigations

Echocardiogram remains the investigation of choice. CXR and ECG are rarely abnormal in innocent murmurs and can give false reassurance — don’t rely on a normal CXR/ECG to exclude structural disease if other red flags are present. Refer to paediatric cardiology for any concern.

Congenital heart disease — acyanotic lesions (atrial septal defect, ventricular septal defect, patent ductus arteriosus, coarctation of the aorta) and cyanotic lesions (tetralogy of Fallot, transposition of the great arteries, tricuspid/ pulmonary atresia, truncus arteriosus).