Heart murmurs in the neonate: an approach to the neonate with a heart murmur

Investigation will vary depending upon local resources and expertise. The following recommendations represent the minimum requirements to ensure the safe management of neonates with heart murmurs and the timely identification of congenital heart disease.

• All infants with a heart murmur on neonatal examination should be reviewed by a senior paediatrician (middle grade or consultant).
• All infants with a heart murmur should remain in hospital until >24 hours old (unless definitive diagnosis is reached before this).
• All infant with a heart murmur should have a detailed cardiovascular clinical examination which must include measurement of pre and post ductal saturations.
• If a baby with a heart murmur is discharged before a definitive diagnosis is reached, the parents should be given a written information leaflet describing warning signs and advising them of what to do in the event that their baby became unwell.

Clinical examination:

• Dysmorphic features
• Signs of heart failure (tachypnoea, increased respiratory effort, hepatomegaly, shock)
• Palpation of brachial and femoral pulses
• Presence of cyanosis (as measured by lower limb saturations – a reading < 96% or >3% difference between pre and post ductal saturations should prompt further investigation ¹)
• Heart sounds
• Presence of a heave
• Murmur – intensity, character, location and radiation

Electrocardiogram

• ECG has been shown to be a sensitive and specific tool for diagnosing atrioventicular septal defect² (more common in infants with Trisomy 21) but has not been shown to aid significantly in the diagnosis of other structural congenital heart disease ³.  It is not necessary to perform an ECG as part of the routine assessment of a baby with a heart murmur.
• If performed, a normal neonatal ECG shows right axis deviation because of the right ventricular dominance of the newborn heart. Left axis deviation in a newborn is a significant abnormal finding and should prompt further investigation.
• Whilst an abnormal ECG should prompt further investigation, a normal ECG should not be considered reassuring if there are abnormal clinical findings or lower limb saturations <96%.

CXR and 4 limb blood pressure

There is no evidence to support the use of CXR or 4 limb blood pressure measurements in the assessment of neonates with heart murmurs ^3,4,5,6.

Echocardiography

• This is the gold standard investigation for differentiating between innocent and pathological murmurs. Some units will undertake an echocardiogram in all neonates with heart murmurs. For many units this is not currently practical.
• In units where it is not feasible to perform echocardiogram for all infants with heart murmurs, information gathered from examination findings and oxygen saturations can be used to determine the need for and timing of echocardiography and follow up:

1. Likely significant congenital heart disease –urgent echocardiogram and review (same day)

Infants with a heart murmur and any of the following warning signs: lower limb saturations < 96%; >3%  pre / post ductal difference; absent/weak femoral pulses; signs of heart failure or shock. These infants require admission to a neonatal unit for consideration of prostaglandin and urgent discussion  +/- transfer to a cardiac centre. If appropriately skilled local PEC or visiting cardiologist is available to perform echocardiogram while retrieval is awaited then this can be linked by telemedicine link / used to update surgical centre. This should not be allowed to delay transfer.

2. Asymptomatic but clinically pathological murmur – soon echocardiogram (pre-discharge or as soon as possible within 1 week)

Infants without any of the above warning signs but with any of the following abnormal clinical findings: dysmorphism; heave; abnormal heart sounds; loud murmur (>2/6); pansystolic, diastolic, continuous murmur; murmur location other than left sternal edge/radiation.

3. Low risk of congenital heart disease - routine review neonatal OPC 2-6 weeks

Well infants with no signs of heart failure, normal pulses, lower limb saturations >96%, soft (1-2/6) systolic murmur at the left sternal edge with no radiation.

Click here to download parent information leaflet (Word)