See also the guideline on screening First Degree Relatives
See also the S.T.A.B.L.E. Cardiac module

National Women's Health acts as the primary delivery unit nationally for infants with an antenatal diagnosis of major congenital heart disease who are likely to need surgical intervention in the newborn period. A fetal cardiology service is provided by the Starship Paediatric and Congenital Cardiology Service and in most instances the anatomical and physiological lesion is able to be identified accurately prior to delivery.

The major cardiac lesions diagnosed antenatally can be generally divided into three groups:

• Duct-dependent for systemic blood flow (e.g. Hypoplastic Left Heart Syndrome, critical aortic stenosis, interrupted aortic arch).
• Duct-dependent cyanotic lesions (e.g. pulmonary atresia, transposition of the great arteries)
• Rhythm disturbances (e.g. congenital heart block, fetal supraventricular tachycardia)

Management in Labour

• A copy of the fetal echocardiography report(s), and Fetal Medicine Panel report if applicable, should be obtained so accurate information is available.
• The obstetric service should notify the Level 3 neonatal registrar or NS-ANP (pager 93-5535) that delivery is anticipated. The registrar or NS-ANP should inform the neonatal unit clinical charge nurse and the neonatal specialist on duty or on call.
• The paediatric cardiologist on call should be informed during normal working hours if the mother is in labour or is going to be induced or electively delivered by caesarean section.
• The paediatric cardiologist has usually already met with the parents to explain what is planned post-delivery.

Immediate Delivery Room Management

• Most infants with major congenital heart disease will not require additional resuscitation at birth and will be asymptomatic of their cardiac disease for hours or days postnatally.
  • An infant who is cyanosed and bradycardic at birth requires effective resuscitation, and the cause of the cyanosis and bradycardia should be assumed to be respiratory and not cardiac.
  • Resuscitation measures may include the administration of oxygen and positive pressure ventilation.
• Cardiac lesions that are responsible for an infant being in poor condition at birth are rare (e.g. severe Ebstein's anomaly, or other cardiac conditions such as arrhythmia, particularly if accompanied by fetal hydrops).
• Following resuscitation and assessment, the infant should be transferred to NICU as soon as practical. The parents should be given the opportunity to hold their baby if the baby's condition allows this.

Initial Management in NICU

Initial management will depend on the underlying cardiac lesion and the anticipated neonatal problems.

• Infants should be admitted to Level 3 NICU.
• Cardiorespiratory and oxygen saturation monitoring should be commenced as soon as possible.
• If the infant is unwell or requiring significant support, take blood cultures and commence antibiotics.
• Intravenous access
  • If the infant requires significant ventilatory support, arterial and venous access should be obtained.
  • Infants with lesions dependent on the duct for systemic blood flow, a double lumen umbilical venous cather should be inserted.
  • For infants with other lesions it is not necessary to insert umbilical catheters if the baby is otherwise well.

Duct-dependent for Systemic Blood Flow

With severe left-sided obstructive lesions systemic blood flow is dependent on right-to-left flow through a patent ductus arteriosus, so these babies are duct-dependent. Examples: Hypoplastic Left Heart Syndrome, critical aortic stenosis, interrupted aortic arch.

• Insert a double lumen umbilical venous catheter
• Commence a prostaglandin infusion at an initial dose of 10 nanograms/kg/min.
• Do not over-oxygenate the infant (over-oxygenation will result in increased pulmonary blood flow and reduced systemic blood flow).
• Accept oxygen saturations of 75% or above.  Reduce inspired oxygen if saturations >85%.
• Contact the paediatric cardiologist on call.
• The baby is to remain nil by mouth.
• If the infant requires assisted ventilation, ensure that the baby is not over-ventilated.  The aim should be to initially ventilate to keep a low-normal arterial pH.  Sedation, muscle relaxation, and controlled hypoventilation to further reduce arterial pH may be necessary if there is excessive pulmonary blood flow and reduced systemic blood flow (oxygen saturations >85%, low MAP, tachycardia, cool peripheries).

Duct-dependent  Cyanotic Lesions

These lesions are duct-dependent either to ensure adequate pulmonary blood flow (e.g. pulmonary atresia, critical pulmonary stenosis) or to ensure adequate mixing between the systemic and pulmonary circulations (transposition of the great arteries).

• Commence a prostaglandin infusion at an initial dose of 10 nanograms/kg/min.
• Ensure that at least one extra IV leur is available in the event that the PGE1 infusion tissues.
• If the systemic oxygen saturation is below 75%, call the paediatric cardiologist on call.
• If the infant develops apnoea or the systemic oxygen saturation is below 75% despite prostaglandin, they should be ventilated.
• If the infant develops apnoea but has a systemic oxygen saturation of 75% or above, the dose of prostaglandin can be reduced (but not below 5 nanograms/kg/min).  If apnoea continues, the infant should be ventilated.
• If the infant is delivered after midnight but is stable, the paediatric cardiologist should be contacted in the morning by 0700 hours. If unstable, contact the paediatric cardiologist on call.

Rhythm Disturbances

Many infants are asymptomatic despite rhythm disturbances which have been detected antenatally or postnatally. Some infants may require significant resuscitation, particularly if they are hydropic. Hydropic infants require the attendance of a neonatal specialist. Severely hydropic infants may require emergency insertion of intercostal and/or abdominal drains at delivery.

Congenital Heart Block

• In the case of complete heart block with fetal hydrops, delivery should be planned in consultation with the paediatric cardiologist and/or paediatric cardiac surgeon on call as urgent pacing may be necessary.
• Transfer to NICU as quickly as possible.
• Intravenous access should be obtained.
• It is preferable but not essential to obtain a 12-lead ECG soon after admission to NICU.
• If the heart rate is above 55bpm and the infant is stable, contact the paediatric cardiologist non-urgently.
• If the heart rate is below 55bpm, contact the paediatric cardiologist on call.
• Do not commence chronotropic agents (e.g. isoprenaline) without first discussing management with the paediatric cardiologist.

Tachyarrhythmias

• Be aware that some pregnant mothers are treated with one or more anti-arrhythmic medications when the fetus has SVT, in order to treat the fetus, thus the baby may have anti-arrhythmic medication(s) on board at delivery.
• If the tachycardia is still present after delivery, transfer to NICU as quickly as possible
• Intravenous access should be obtained.
• Obtain a 12-lead ECG soon after admission to NICU. During normal working hours contact the ECG technicians; after-hours, medical or nursing staff will need to perform the ECG.
• Contact the paediatric cardiologist on call to discuss further management.
• If the tachycardia has resolved by delivery and the infant is stable, the baby can be admitted to the postnatal ward under paediatric care. The baby should have Q4H observations initially. Arrange review by the neonatal specialist on call the following morning with a 12 lead ECG available.