Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
See also separate article Heart Auscultation.
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. However, a murmur can be the sole manifestation of structural heart disease; therefore, a careful evaluation is essential. If in doubt, referral to a paediatrician with expertise in cardiology (PEC) or paediatric cardiologist is necessary.
Distinguishing innocent from pathological murmurs
Paediatric cardiologists are good at recognising innocent murmurs and sensitivity and specificity as high as 96% and 95% has been reported.However, this clinical ability does not extend to other groups of clinicians. Diagnostic accuracy of clinical assessment by office-based paediatricians in Canada (equivalent to paediatric consultants in the UK) was found to be sub-optimal with a sensitivity of 82% and specificity of 72%. Another study evaluating clinical auscultatory skills in paediatric residents using a cardiovascular patient simulator found a diagnostic accuracy of only 33%.Even in trainees undergoing a cardiology rotation as part of their training, the ability to make specific diagnosis remains poor and diagnostic accuracy for distinguishing normal from abnormal cases is 73%.
Does this child have heart disease?
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:
- Are there any symptoms and signs of heart disease?
- Are there any predisposing medical conditions?
- 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:
|Excessive sweating||Chest pain|
|Generally unwell||Pedal oedema|
|Not gaining weight||Positive family history|
|Positive family history|
Signs of heart disease
|Poor peripheral pulses||Poor peripheral pulses|
|Low oxygen saturations||Elevated jugular venous pressure (JVP)|
|Faltering growth (growth chart)||Pedal oedema|
|Basal lung crepitations|
Predisposing medical conditions
- Down's syndrome
- Noonan's syndrome
- Turner syndrome
- Marfan's syndrome
- Fetal alcohol syndrome
- Fetal rubella infection
Characteristics of the murmur
Each heart murmur must be analysed in terms of intensity (grade 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 border||Pulmonary stenosis (PS), atrial septal defect (ASD), innocent pulmonary flow murmur, tetrology of Fallot (TOF), coarctation of the aorta (CoA), aortic stenosis (AS), patent ductus arteriosus (PDA) with pulmonary hypertension|
|Upper right sternal border||AS, supravalvular AS, subaortic stenosis|
|Lower left sternal border||Ventricular septal defect (VSD), Still's murmur, hypertrophic obstructive cardiomyopathy (HOCM), tricuspid regurgitation (TR)|
|Apical area||Mitral regurgitation (MR), mitral valve prolapse (MVP), HOCM, vibratory innocent murmur|
Likewise timing of the murmur can help identifying the cause of the murmur:
|VSD||Aortic regurgitation (AR)||PDA|
|TR||Pulmonary regurgitation (PR)||Venous hum|
|MR||Mitral 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:
|Still's murmur||Mid-left sternal border, mid-systolic, grade 2-3, twanging string, musical, vibratory sound||VSD|
|Pulmonary flow murmur||Upper left sternal border, mid-systolic, grade 1-3, grating||PS, ASD|
|Venous hum||Right and/or left infraclavicular, continuous, only heard in upright position, diastolic component louder than systolic||PDA|
|Carotid bruit (supraclavicular systolic murmur)||Supraclavicular area, ejection systolic, grade 2-3||AS|
|Peripheral pulmonary stenosis (pulmonary flow murmur of newborn)||Upper left sternal border, grade 1-2, radiates to axillae and back, usually disappears by 6 months of age||PS|
Neonatal heart murmurs
Heart murmurs in neonates are much more likely to indicate structural heart disease and should prompt specialist assessment. Less than 1% of newborns have a heart murmur but more than 50% of those with a murmur have structural heart disease.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.
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.
Evaluation of 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:
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.
Patient and family education
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 & references
- Children's Heart Federation; Children's Heart Federation
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