Heart Murmurs in Children

Last updated by Peer reviewed by Dr Laurence Knott
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This article is for Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Heart Disease article more useful, or one of our other health articles.

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See also the separate Heart Auscultation article.

Heart murmurs are common in asymptomatic and otherwise well children. Many murmurs are innocent and result from normal patterns of blood flow through heart and blood vessels[1].

However, a murmur can be the sole manifestation of structural heart disease. More than 50% of newborns with congenital heart disease are unrecognised at birth[2]. Therefore, a careful evaluation is essential. If in doubt, referral to a paediatrician with expertise in cardiology (PEC) or a paediatric cardiologist is necessary.

Does this child have heart disease?[3]

The key question which is raised on the detection of a heart murmur is: 'Does this child have a heart disease?' To answer this, three groups of factors need to be considered:

  1. Are there any symptoms and signs of heart disease?
  2. Are there any predisposing medical conditions?
  3. What are the characteristics of the murmur?

Symptoms of heart disease

The symptoms vary with the age of the child and are more nonspecific in infants. One or more of the following may be present:

InfantOlder Child
BreathlessnessExercise intolerance
Poor feedingPalpitations
Excessive sweatingChest pain
Blue episodesSyncope
Generally unwellPedal oedema
Not gaining weightPositive family history
Positive family history 

Signs of heart disease

InfantOlder Child
Poor peripheral pulsesPoor peripheral pulses
Low oxygen saturationsElevated jugular venous pressure (JVP)
Faltering growth (growth chart)Pedal oedema
 Basal lung crepitations

Predisposing medical conditions

Each heart murmur must be analysed in terms of intensity (grades 1 to 6), timing (systolic or diastolic), location, transmission and quality (musical, vibratory, blowing, harsh, etc).

A grade 1 murmur is barely audible, grade 2 is soft but easily heard, grade 3 is loud but not accompanied by a thrill, while grade 4 is associated with a thrill. Grade 5 and 6 are very loud murmurs which may be audible with stethoscope partly or completely off the chest.

Most murmurs are systolic and location of a systolic murmur can point toward specific cardiac diagnosis as described in the table below:

Upper left sternal borderPulmonary stenosis (PS), atrial septal defect (ASD), innocent pulmonary flow murmur, tetralogy of Fallot (TOF), coarctation of the aorta (CoA), aortic stenosis (AS), patent ductus arteriosus (PDA) with pulmonary hypertension
Upper right sternal borderAS, supravalvular AS, subaortic stenosis
Lower left sternal borderVentricular septal defect (VSD), Still's murmur, hypertrophic obstructive cardiomyopathy (HOCM), tricuspid regurgitation (TR)
Apical areaMitral regurgitation (MR), mitral valve prolapse (MVP), HOCM, vibratory innocent murmur

Likewise timing of the murmur can help in identifying the cause of the murmur:

VSDAortic regurgitation (AR)PDA
TRPulmonary regurgitation (PR)Venous hum
MRMitral stenosis (MS)Arteriovenous malformations (AVMs)

Diastolic murmurs are pathological. Six cardinal signs are described which indicate that a systolic murmur is likely to be pathological, ie because of an underlying heart defect. These are:

  • Holosystolic (pansystolic) murmur.
  • Harsh murmur.
  • Abnormal heart sounds.
  • Early or mid-systolic click.
  • Grade 3 murmur or greater.
  • Heard over upper left sternal border.
  • Sensitive (changes with child's position or with respiration).
  • Short duration (not holosystolic).
  • Single (no associated clicks or gallops).
  • Small (murmur limited to a small area and not radiating).
  • Soft (low amplitude).
  • Sweet (not harsh-sounding).
  • Systolic (occurs and is limited to systole).

Five types of innocent murmurs in childhood are described, all with diagnostic clinical features. However, the differential diagnosis always includes pathological murmurs because of various heart defects. These are summarised below:

Innocent Murmurs

Still's murmurMid-left sternal border, mid-systolic, grades 2-3, twanging string, musical, vibratory soundVSD
Pulmonary flow murmurUpper left sternal border, mid-systolic, grades 1-3, gratingPS, ASD
Venous humRight and/or left infraclavicular, continuous, only heard in upright position, diastolic component louder than systolicPDA
Carotid bruit (supraclavicular systolic murmur)Supraclavicular area, ejection systolic, grades 2-3AS
Peripheral pulmonary stenosis (pulmonary flow murmur of newborn)Upper left sternal border, grades 1-2, radiates to axillae and back, usually disappears by 6 months of agePS

Heart murmurs in neonates are much more likely to indicate structural heart disease and should prompt specialist assessment.

One study of 6,333 healthy newborn babies found heart murmurs in 87 (1.37%) neonates, of whom 42.5% had a structural cardiac malformation. Ventricular septal defect (62%) was the most common diagnosis, followed by atrial septal defect, pulmonary stenosis and patent ductus arteriosus[5].

Even potentially life-threatening heart defects may have no other signs or symptoms in addition to the heart murmurs. A very thorough evaluation including detailed clinical examination, femoral pulse check along with pulse oximetry (pre- and post-ductal saturations) is mandatory. Those with clinical signs, difficult-to-palpate femoral pulses or low oxygen saturations require prompt echocardiographic assessment. Neonates with heart murmurs who are clinically asymptomatic should also be referred for a routine echocardiographic assessment.

ECG and CXR have limited use in the diagnosis of underlying pathology associated with pathological heart murmurs, with low sensitivity and specificity for identifying cardiac defects or anatomical abnormalities.

Echocardiography is the gold standard to diagnose congenital cardiac malformations definitively in paediatric patients. It is indicated in any child with an asymptomatic heart murmur which has attributes of a pathological murmur or when the examiner is not comfortable in making a clinical diagnosis of an innocent heart murmur. This can usually be done by a PEC in a district general hospital setting, minimising the need for referral to a tertiary cardiology service[6].

Any child found to have a heart murmur should have a thorough clinical evaluation including pulse oximetry and palpation of femoral pulses. Clinically unwell children or those with red flags such as difficult-to-feel femorals or low oxygen saturations need urgent referral for specialist cardiac evaluation. It is important to remember that absence of symptoms does not exclude important pathology. If in doubt, referral to a PEC or a paediatric cardiologist is essential. The American College of Cardiology recommends a low threshold for echocardiographic evaluation of heart murmurs, as shown below[7].

Evaluation of murmurs[7]

Systolic murmurs

  • Grade 2 or less:
    • Asymptomatic and no associated signs - no further workup.
    • Symptomatic or other signs of cardiac disease - echocardiogram.
  • Grade 3 or more - echocardiogram.

Early systolic, late systolic, holosystolic:

  • Echocardiogram.

Diastolic and continuous murmurs
All diastolic and continuous murmurs must be evaluated using echocardiography.

The National Institute for Health and Care Excellence (NICE) no longer recommends routine antibiotic prophylaxis in children with structural heart disease but emphasises the importance of maintaining good oral health[8].

Once a heart murmur is confirmed to be innocent, reassurance to the family regarding its benign nature is important. Although the murmur may never disappear and may persist into adulthood, the parent and child need to be specifically reassured that an innocent murmur is simply an additional noise audible to the clinician and not a disease or illness, and is therefore completely harmless.

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Further reading and references

  1. Doshi AR; Innocent Heart Murmur. Cureus. 2018 Dec 510(12):e3689. doi: 10.7759/cureus.3689.

  2. Yoon SA, Hong WH, Cho HJ; Congenital heart disease diagnosed with echocardiogram in newborns with asymptomatic cardiac murmurs: a systematic review. BMC Pediatr. 2020 Jun 3020(1):322. doi: 10.1186/s12887-020-02212-8.

  3. Evaluation of suspected congenital heart disease; Paediatrics and Child Health, January 2011

  4. Frank JE, Jacobe KM; Evaluation and management of heart murmurs in children. Am Fam Physician. 2011 Oct 184(7):793-800.

  5. Lardhi AA; Prevalence and clinical significance of heart murmurs detected in routine neonatal examination. J Saudi Heart Assoc. 2010 Jan22(1):25-7. doi: 10.1016/j.jsha.2010.03.005. Epub 2010 Mar 10.

  6. Managed Care Network for the assessment of cardiac problems in children in a district general hospital: a working model; Arch Dis Child. Nov 2006 91(11): 892–895

  7. Nishimura RA, Otto CM, Bonow RO, et al; 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014 Jun 10129(23):2440-92. doi: 10.1161/CIR.0000000000000029. Epub 2014 Mar 3.

  8. Prophylaxis against infective endocarditis: Antimicrobial prophylaxis against infective endocarditis in adults and children undergoing interventional procedures; NICE Clinical Guideline (March 2008 - last updated July 2016)