Your child’s diagnosis
Tetralogy of Fallot
01
How blood flows
Tetralogy of Fallot
The same region in both views. The usual view is a comparison, not a treatment result.
Tetralogy of Fallot · connections before repair
- Less oxygen
- Mixed blood
- More oxygen
Step 1 of 4
A narrowed lung outlet
Narrowing in the right ventricular outflow makes it harder for blood to reach the lungs.
How to read this map
Follow the arrows to see connections. This is a map, not the shape or position of a heart. Both sides work together; the story follows one part at a time. A crossing with a white gap is not a connection; a dot marks a junction. With story controls focused, use left/right arrows, Home or End.
A simplified example with forward flow to the lungs; anatomy and severity vary.
Colours describe this example: blue means less oxygen, red more oxygen, and purple mixing. Blood is always red in real life. Line widths and animation do not measure flow, pressure, oxygen saturation or severity.
RV wall thickening is a structural feature, not another flow route.
The routes show connections, not exact mixing proportions.
Diagram sources and scope
A simplified example with forward flow to the lungs; anatomy and severity vary.
Original Heart Up Close connection map · Source check: 26 October 2026 · Independent clinical review pending.
Tetralogy of Fallot
- A narrowed lung outlet. Narrowing in the right ventricular outflow makes it harder for blood to reach the lungs.
- A VSD between the ventricles. An opening in the ventricular wall sits beneath the aortic outlet.
- An overriding aorta receives from both. The aorta sits above the opening and can receive blood from both ventricles.
- Mixed blood to the body. The shared aortic outlet can carry blood with less oxygen than usual. The amount depends on the anatomy and narrowing.
A simplified example with forward flow to the lungs; anatomy and severity vary.
02
Diagnosis and care
Diagnosis and tests
The condition may be seen during pregnancy. After birth, low oxygen levels, feeding difficulties or breathlessness may lead to tests. A murmur, an extra sound during the heartbeat, may also be heard. Some children have hypercyanotic or “tet” spells. These are episodes when oxygen levels fall suddenly. Ask for your child’s emergency plan. A spell needs urgent assessment.
An echocardiogram, or echo, is an ultrasound scan of the heart. It shows the opening and the route to the lungs. The team also checks oxygen levels. An ECG records the heart’s electrical signals. Other scans or a catheter test, which passes a thin tube through a blood vessel towards the heart, may help plan treatment.
The team needs to understand the arteries to the lungs and other heart details before explaining surgery.
Care and follow-up
Repair usually closes the opening and widens the route to the lungs. Some babies first need a shunt, a new connection that helps blood reach the lungs. A catheter procedure, using a thin tube in a blood vessel, may be another first step. Other babies go straight to repair. The order differs between children.
Ask why the team recommends this plan and what its risks are.
The pulmonary valve controls blood leaving the right ventricle towards the lungs. It may leak or become narrowed after repair. The pattern of heartbeats also needs checking. Further procedures, including valve treatment, may be needed later. Regular specialist checks remain important. “Repair” names an operation. It does not mean the heart will never need more care.
Daily life
Before leaving hospital, ask what oxygen levels and symptoms are expected for your child and how to obtain urgent help. Ask the team to demonstrate any emergency steps they want you to know. Discuss what nursery or school staff need in the care plan.
03
Questions to ask
Save the questions you want to take to your next appointment. You can edit them in your Journal.
- How narrow is the route from the right ventricle to the lungs, and how is that affecting our child’s blood flow?
- Does our child need a temporary procedure before the main repair, and what would it help with?
- Could you give us a written plan explaining how to recognise a spell and exactly what to do if one happens?
- How will you check the valve on the route to the lungs after repair, and what changes might need further treatment?
- What should nursery or school know about our child’s heart, and can you help us prepare a clear care plan?
Sources and review
Sources checked 9 October 2026. Independent clinical review pending.
- British Heart Foundation: Tetralogy of Fallot
Accessed 9 October 2026
- Children’s Heart Federation: Tetralogy of Fallots Information Sheet
Accessed 9 October 2026