Children with some types of heart problems can have what is called a blue (cyanotic) spell. This is more frequent in children with Tetralogy of Fallot.

Cyanosis is the bluish tinge that can be seen on the nail beds and the skin, especially around the mouth and on the lips

Tetralogy of Fallot is caused by a combination of four heart defects present at birth:

  • pulmonary valve stenosis – a narrowing of the pulmonary valve and thickening of the muscle below 
  • ventricular septal defect – a hole between the two main pumping chambers of the heart
  • overriding aorta – the aorta (the largest artery in the body) is positioned directly over a ventricular septal defect, instead of over the left ventricle
  • right-ventricular hypertrophy – thickening of the muscle wall.

Some children with Tetralogy of Fallot may experience blue (cyanotic) spells, which are caused by a spasm of the right-ventricular outflow tract. As a result, blood flow to the lungs is reduced, causing cyanosis.


Blue spells can occur for no reason, but will most commonly happen when your child is:

  • crying
  • in pain
  • having a bowel movement / passing wind
  • is dehydrated (not taking enough fluid)
  • has a fever.

During a spell, the lips and skin will appear bluish and breathing may appear faster. Your child may initially become very irritable, then sleepy and unresponsive.

Please remain calm and follow these steps to help your child: 

  • Place your child on their back.
  • Bring their knees up to touch their chest. 
  • Cuddle and comfort your child.
  • For an older child, lie them on their side and bring knees up to the chest.

If spells continue for longer than five minutes, call 999 for an ambulance and take your child to your nearest local hospital.

Remember to take a clinic letter or discharge summary with you so that staff are aware of your child’s heart condition.

Your child may need to start on a medication called propanalol. This will help to relax the muscle below the pulmonary artery.

It may mean that your child needs an operation if they start experiencing blue spells. An appointment will be arranged with their cardiologist at Royal Brompton Hospital.

For children with cyanotic heart defects, extra care should be taken:

  • if they have vomiting and diarrhoea or develop a high temperature – if this lasts longer than 24 hours, an appointment should be made with your GP
  • during hot weather – make sure your child is well hydrated, with frequent access to liquids.


Telephone: 020 7349 7727

Read about our paediatric cardiac nurse specialists