FFinalistSouthampton · 2027
Child health
AKT · Child health/Congenital heart

Innocent murmur

Benign flow murmur in a structurally normal heart (no pathology)

Overview

A benign murmur in a structurally normal heart — very common in children, especially during fever/illness (increased flow). Recognised by the '7 S's': Soft, Systolic, aSymptomatic, left Sternal edge, no radiation, normal heart Sounds, and changes with poSture/Sitting. The skill is confidently distinguishing it from pathology so as to reassure (and not over-investigate) while referring the murmurs that need an echo.

Recognise

  • SOFT, SYSTOLIC (never purely diastolic), ASYMPTOMATIC child, varies with posture/respiration, often louder with fever/anaemia/exercise
  • Normal heart sounds, NO thrill, no radiation, normal pulses, normal growth/saturations
  • Types: Still's murmur (vibratory, lower left sternal edge), venous hum (continuous, disappears lying flat/turning head), pulmonary flow murmur

Red flags

  • RED-FLAG features that mean refer/echo (NOT innocent): diastolic murmur, pansystolic, loud (≥grade 3)/thrill, harsh, abnormal S2, radiation, symptoms (cyanosis/failure/faltering growth), abnormal pulses (femoral), family history of CHD/sudden death

Differentials & how to tell them apart

VSDpansystolic at the lower left sternal edge ± thrill
ASDfixed split S2
Aortic/pulmonary stenosisejection click, radiation, thrill
PDAcontinuous machinery murmur, bounding pulses

Investigations

Clinical recognition; ECHOCARDIOGRAPHY if any red-flag feature or diagnostic uncertainty (otherwise none needed).

Management

Reassurance (no treatment); echo only if any red-flag feature

  1. 1Recognise the innocent murmur by the 7 S's and a normal examination; reassure and discharge without investigation.Gate: Refer/echo any murmur with a RED FLAG — diastolic, pansystolic, loud/thrill, harsh, abnormal/fixed S2, radiation, symptoms, abnormal femoral pulses, or a family history of CHD/sudden death — these are NOT innocent
  2. 2Echocardiography for flagged murmurs; reassurance and discharge for clearly innocent ones.
None — reassurance — no treatment; safety-net and discharge if clearly innocent

Key points

Soft, systolic, asymptomatic, varies with posture, normal sounds/pulses = innocent murmur → reassure. The skill is spotting the red flags (diastolic, pansystolic/loud/thrill, abnormal S2, symptoms, abnormal pulses, family history) that earn an echo.

Monitor & prognosis

None if innocent; re-assess if features change.

Benign.

Source: RCPCH; NICE (murmurs in children)