Child Health · Heart
Heart Murmur in Children — Innocent or Worry?
70-80% of children have a heart murmur at some point. Most are INNOCENT (normal blood flow). Red flags for pathological murmurs (diastolic, loud, with symptoms), when to refer, what an echo shows. RCPCH / NICE.
Last reviewed 2 June 2026
Paediatric heart murmur
Innocent vs pathological — referral decision
Red flags (tick all that apply)
Action
Likely innocent murmur — no echo required
Soft (≤ grade 2/6), systolic-only, localised, position/respiration-variable, with normal heart sounds, pulses, growth, and SpO2 — this is the classic innocent murmur profile. Reassure family. No echo, no restrictions. Document in notes; re-examine at routine well-child visits. Innocent murmurs are most prominent in well children aged 3–7 and typically disappear by adolescence.
Common innocent murmur signatures
- Still’s murmur: 3–7 yr, “musical”/vibratory, low-mid LSB, varies with position, quieter when sitting up.
- Pulmonary flow murmur: upper LSB, ejection-systolic, blowing, louder supine + expiration.
- Venous hum: continuous, infraclavicular, DISAPPEARS supine or with jugular compression / head turn.
- Supraclavicular bruit: brief, just above clavicle, vanishes with shoulder hyperextension.
- Peripheral pulmonary stenosis of newborn: < 6 mo, axilla and back, resolves by 6 mo — pathological if persists.
Troubleshooting + common pitfalls
- Pitfall: Calling a diastolic murmur innocent.
Solution: ANY diastolic component is pathological until proven otherwise — refer. There is no innocent diastolic murmur. - Pitfall: Missing coarctation of the aorta in a child with a soft systolic murmur.
Solution: Always check 4-limb BP and femoral pulses in any child with a murmur. Radio-femoral delay or upper-vs-lower BP gradient > 20 mmHg = coarctation until proven otherwise. - Pitfall: Ignoring family history.
Solution: Family hx of CHD, sudden cardiac death < 50 y, or Marfan independently lowers the threshold to refer for echo + ECG. - Pitfall: Treating a febrile child’s murmur as a permanent finding.
Solution: Hyperdynamic state (fever, anaemia, exercise) accentuates innocent murmurs. Re-auscultate when the child is well before deciding. - Pitfall: Persistent murmur in a newborn at 1 month dismissed as innocent.
Solution: Any persistent murmur beyond the first month of life warrants echo. Most innocent newborn murmurs (PPS, transient flow) resolve in the first few weeks. - Pitfall: Not differentiating wide-fixed-split S2 from physiological split.
Solution: Physiological split S2 varies with respiration (wider on inspiration). FIXED wide-split S2 is the hallmark of ASD — doesn’t change with breathing. Listen during deep, slow breaths. - Pitfall: Missing 22q11.2 / Williams / Down associations.
Solution: Syndromic features warrant echo regardless of murmur grade because of high CHD prevalence (Down ~50 %, 22q11.2 ~75 %, Williams ~80 %). - Pitfall: Sport clearance without symptom screen.
Solution: AHA pre-participation 14-item screen + physical — exercise syncope, family hx SCD, or murmur with red flag → cardiology before clearance. - Pitfall: Calling a venous hum continuous-and-pathological.
Solution: Venous hum is continuous but vanishes supine or with jugular compression. PDA continuous murmur stays in any position. - Pitfall: Treating a child with a single S2 as innocent.
Solution: Single S2 (no audible split) is pathological — pulmonary atresia, severe pulmonary stenosis, truncus, transposition (rare but serious). Refer. - Pitfall: No SpO2 check on a child with a murmur.
Solution: Pre- and post-ductal SpO2 is part of any murmur assessment in the newborn period; gradient > 3 % = critical CHD until proven otherwise. - Pitfall: Calling all pulmonary flow murmurs innocent in adolescence.
Solution: Most are, but ASD can present in late childhood / adolescence with a pulmonary flow murmur + fixed split S2. Always listen for the split.
Educational tool only — not medical advice. AAP Section on Cardiology; NICE NG143; Frank 2011 AFP. Decisions made by paediatric / family medicine with cardiology where indicated.
What does this mean?
Heart murmurs are heard in ~50 % of healthy children at some point; the vast majority are innocent flow murmurs that resolve by adolescence. The clinical task is differentiating the innocent (no echo, reassurance) from the pathological (echo + cardiology), without over-referring well children or under-referring quiet CHD. The five most useful discriminators — in order — are (1) any diastolic component (always pathological); (2) grade and thrill (≥ 3/6 or thrill = beyond innocent range); (3) heart sounds (fixed wide-split S2 = ASD, single S2 = serious CHD, click/gallop = pathological); (4) pulses and 4-limb BP (coarctation lurks behind a soft murmur); (5) systemic features (cyanosis, failure to thrive, syndromic phenotype, family hx). The classic innocent profile — Still’s murmur (musical, low LSB), pulmonary flow, venous hum (continuous but disappears supine), supraclavicular bruit — is short, soft, systolic, position-variable, in a well child with normal exam. Persistent newborn murmurs beyond the first month and any new murmur in a syndromic child warrant echo regardless of grade.
Should I worry about my child’s heart murmur?
Usually not. 70-80% of children have an “innocent” murmur at some point — caused by normal blood flow through normal heart structures.
Pathological murmurs (real heart problem) rare but need identification.
Innocent murmur types
- Still’s: vibratory/musical; ages 3-6 commonest.
- Pulmonary flow: soft systolic; left sternal border.
- Peripheral pulmonic stenosis: neonatal; resolves by 6 months.
- Venous hum: continuous; neck; sitting up.
Soft (grade 1-2/6); vary with position; louder if febrile / anaemic / anxious.
Red flags (pathological)
- Diastolic murmur (between heart beats).
- Loud (grade 3+/6).
- Harsh quality.
- Heaves / thrills (palpable).
- Abnormal heart sounds.
- Cyanosis.
- Failure to thrive.
- Breathless during feeds.
- Poor feeding.
- Hepatomegaly.
- Sweating during feeds.
- Recurrent chest infections.
- Family history of congenital heart disease.
Any of these: paediatric cardiology referral.
Assessment
- History (feeding, growth, breathing, family).
- Full cardiac exam + femoral pulses.
- Pulse oximetry.
- ECG if any concern.
- Echocardiogram — definitive test.
When do innocent murmurs disappear?
- Peripheral pulmonary stenosis: by 6 months.
- Still’s: usually adolescence.
- Pulmonary flow: through teens.
- Some persist as normal variant in adulthood.
Common congenital heart defects
- VSD: ventricular septal defect (commonest, ~30%); often closes spontaneously.
- ASD: atrial septal defect.
- PDA: patent ductus arteriosus.
- Valve stenosis / regurgitation.
- Coarctation of aorta.
VSD outlook
- Small: ~50% close by age 5; no symptoms; serial echoes.
- Medium: diuretics; surgery if heart enlargement.
- Large: surgical closure in infancy.
Most children with VSD lead normal lives. Surgical outcomes excellent.
Can my child exercise?
Innocent murmurs: completely normal exercise. Small defects: usually full activity. Some defects: graded restrictions (cardiologist guides). Most kids: school sport, swimming, family activities fine.
NIPE check at 6-8 weeks
Routine cardiac assessment. Pulse oximetry screening at 24h+ in many UK trusts catches critical CHD. Femoral pulse check rules out coarctation.
Hereditary?
Innocent murmurs: not hereditary. CHD: some hereditary; some genetic syndromes (Down’s, DiGeorge 22q11, Williams, Marfan, Turner). Family history: ~2-3x risk in siblings; fetal echo at 20-22 wk worth considering next pregnancy.
Different scenarios
Scenario 1: 4-year-old with mid-systolic vibratory murmur, otherwise well
Likely Still’s (innocent). Reassure. Recheck at next routine visit. May refer for echo if first detection.
Scenario 2: Newborn, loud murmur day 2, mild cyanosis
Pulse oximetry + urgent echo. Possible critical CHD. Cardiology assessment.
Scenario 3: Family history of VSD, 6-week check shows murmur
Echo recommended given family history.
Scenario 4: Asymptomatic 2-year-old, soft murmur present 6 months
Most likely innocent. Echo for reassurance if not previously done.
Scenario 5: Echo shows small VSD
Serial echoes; many close spontaneously by age 5. Endocarditis prophylaxis discussion only if specific high-risk circumstances.
Care guidance — child heart murmur
- Most murmurs innocent.
- Red flags trigger cardiology referral.
- Echo definitive.
- Most CHD treatable; excellent outcomes.
- Pulse oximetry screening picks up critical CHD.
- Family history relevant.
- Most kids fully active.
- CHD support: Children’s Heart Federation, Little Hearts Matter.
Sources
- RCPCH. Paediatric cardiology referral standards.
- NICE. Suspected sepsis in under-5s (mentions murmur context).
- Children’s Heart Federation. chfed.org.uk.
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Frequently asked questions
My child has a heart murmur — should I worry?
USUALLY NOT. 'Innocent murmurs' affect 70-80% of children at some point — caused by NORMAL blood flow patterns through normal heart structures. NOT a sign of heart disease in most cases. PATHOLOGICAL murmurs (real heart problem) are RARE in children, but need identification. ASSESSMENT by GP / paediatrician determines which type. NEVER ignore — but most don't need treatment.
What's an 'innocent' murmur?
BENIGN murmur from normal blood flow. COMMON types: (1) STILL'S MURMUR — vibratory/musical; mid-systolic; loudest left sternal border; ages 3-6 commonest; (2) PULMONARY FLOW MURMUR — soft systolic; left sternal border; through any age; (3) PERIPHERAL PULMONIC STENOSIS — neonatal; resolves by 6 months; (4) VENOUS HUM — continuous; neck; sitting up. CHARACTERISTICS: usually SOFT (grade 1-2/6); VARY with position; LOUDER if febrile / anaemic / anxious; otherwise NORMAL heart sounds + clinical exam.
What's a pathological murmur?
Murmur from a STRUCTURAL HEART CONDITION. EXAMPLES: (1) VENTRICULAR SEPTAL DEFECT (VSD) — hole between ventricles; (2) ATRIAL SEPTAL DEFECT (ASD) — hole between atria; (3) PATENT DUCTUS ARTERIOSUS (PDA) — vessel that should close at birth; (4) VALVE problems (stenosis, regurgitation); (5) COARCTATION of aorta; (6) AORTIC stenosis. SUGGESTIVE features: loud (grade 3+); harsh quality; diastolic; loud heart sounds; thrill (palpable vibration); CARDIAC SYMPTOMS (failure to thrive, breathlessness, cyanosis, fatigue with feeding/playing).
What signs would concern doctors?
RED FLAGS: (1) DIASTOLIC murmur (between heart beats) — almost always pathological; (2) LOUD (grade 3+/6); (3) HARSH quality; (4) HEAVES / THRILLS (palpable on chest); (5) ABNORMAL heart sounds; (6) CYANOSIS; (7) FAILURE TO THRIVE; (8) BREATHLESS during feeds; (9) POOR feeding; (10) HEPATOMEGALY (enlarged liver); (11) SWEATING during feeds; (12) RECURRENT chest infections; (13) FAMILY history of congenital heart disease. ANY of these: paediatric / cardiology referral.
How is a murmur assessed?
(1) HISTORY: feeding, growth, breathing, family history; (2) EXAMINATION: full cardiac exam — heart sounds, murmur characteristics (timing, location, radiation, intensity), femoral pulses (coarctation check), oxygen saturations; (3) ECG (electrocardiogram) — if any concern; (4) ECHOCARDIOGRAM (heart ultrasound) — definitive test; performed by cardiac sonographer + paediatric cardiologist; (5) CHEST X-RAY sometimes. NHS PATHWAY: GP/paediatrician refers if concern; cardiology clinic; echo + cardiologist review.
When do innocent murmurs disappear?
VARY: (1) NEONATAL peripheral pulmonary stenosis — by 6 months. (2) STILL'S MURMUR — usually adolescence (sometimes earlier). (3) PULMONARY FLOW — through teens. (4) VENOUS HUM — same. (5) SOMETIMES persist into adulthood as 'normal variant'. SOMETIMES INTERMITTENT — present when febrile / anxious / anaemic; gone when calm/well. REASSURING when no other concerns + previous normal cardiac assessment.
Should my child have an echocardiogram?
DEPENDS on clinical concern. INDICATIONS: red flags (above); FAMILY HISTORY of congenital heart disease; SYNDROMES with heart association (Down's, DiGeorge, Williams, Marfan, Turner); ABNORMAL ECG; UNCERTAIN clinical impression of innocent vs pathological. NHS: usually 4-6 week wait; URGENT if symptomatic. PRIVATE: ~£200-500; faster access. RESULT informs next steps — most are normal.
What if it's a hole in the heart (VSD)?
VSD = VENTRICULAR SEPTAL DEFECT, most common congenital heart defect (~30%). SMALL VSDs: ~50% close spontaneously by age 5; no symptoms; no treatment needed; serial echoes monitor. MEDIUM VSDs: may need diuretics; surgery later if heart enlargement / pulmonary hypertension. LARGE VSDs: often need surgical closure in infancy (heart failure, pulmonary hypertension risk). MOST CHILDREN with VSD lead NORMAL LIVES. SURGICAL outcomes excellent. ENDOCARDITIS prophylaxis if specific high-risk circumstances (less commonly needed now).
Can my child exercise?
MOST KIDS WITH MURMURS — yes, normal activity. INNOCENT murmurs: completely normal exercise. SMALL DEFECTS (VSD, ASD): usually full activity. SOME defects: graded activity restrictions until corrected (e.g. aortic stenosis severe — avoid intense competitive sport). CARDIOLOGIST guides individualised. SCHOOL SPORT, swimming, family activities mostly fine. INVISIBLE condition — children + parents may face anxiety; counselling helps.
Will it affect their development?
INNOCENT MURMURS: no impact on growth or development. SIGNIFICANT congenital heart disease can affect growth (failure to thrive), exercise tolerance, behaviour (oxygen-dependent). MOST corrected defects: catch up + normal lives. PSYCHOSOCIAL impact: 'heart kid' identity sometimes; school awareness; sport participation. SUPPORT: Children's Heart Federation, Little Hearts Matter (UK).
Will my child need surgery?
DEPENDS. SMALL VSDs / PDAs: often close on their own; no surgery. LARGE defects / valve problems: may need: (1) CATHETER intervention (less invasive — closing device); (2) OPEN HEART SURGERY (cardiopulmonary bypass). TIMING: critical defects early (newborn-infancy); others at school age or later. RECOVERY: usually well; scar minimal (chest); return to normal life. UK SPECIALIST centres (Great Ormond Street, Birmingham, etc.) excellent outcomes.
Are murmurs hereditary?
INNOCENT murmurs: not hereditary (just normal variant). CONGENITAL HEART DEFECTS: SOME hereditary; SOME genetic syndromes (Down's, DiGeorge 22q11, Williams, Marfan, Turner, Noonan). FAMILY HISTORY of CHD: increased risk in siblings (~2-3x); routine fetal echocardiogram in NEXT pregnancy worth considering. GENETIC COUNSELLING if specific syndromes. NOT YOUR FAULT — usually no clear cause.
Pregnancy check after diagnosis?
IF YOUR CHILD has CHD or you have family history: NEXT PREGNANCY worth fetal echo at 20-22 weeks (more detailed than routine anomaly scan). PRECONCEPTION CONSULTATION worthwhile. GENETIC COUNSELLING if specific syndrome. MOST FUTURE PREGNANCIES uneventful. AWARENESS allows early detection if affected.
What about the 6-8 week baby check?
ROUTINE NEWBORN INFANT PHYSICAL EXAMINATION (NIPE) at 0-72h + 6-8 weeks includes cardiac assessment. PULSE OXIMETRY screening at 24h+ in many UK trusts (catches critical CHD). FEMORAL PULSE check (rules out coarctation). MURMUR HEARD: if persistent / pathological features, referral. SOMETIMES innocent murmur at 6 weeks resolves by 6 months. KEY age for picking up CHD.
How does this relate to other calculators on BumpBites?
Companion: /calculators/apgar-score (pulse component); /calculators/baby-percentile (growth); /calculators/milestone-tracker; /calculators/pews-paediatric; /calculators/baby-fever; /calculators/baby-cough (respiratory issues).