Your child’s diagnosis
Single ventricle conditions
01
How blood flows
Single ventricle circulation
A comparison of pumping jobs; exact heart connections vary. The usual view is a comparison, not a treatment result.
Single ventricle · a circulation concept
- Less oxygen
- Mixed blood
- More oxygen
Step 1 of 3
Body and lung blood return
Less-oxygenated blood returns from the body, and oxygenated blood returns from 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 concept map, not a specific diagnosis or surgical stage. “Single ventricle” means one ventricle does the effective pumping work, not necessarily only one anatomical ventricle.
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.
The other ventricle may be present but too small or otherwise unable to do its usual pumping job.
Arrows represent destinations; outlet anatomy, obstruction and the amount of mixing vary. No equal flow split is implied.
Diagram sources and scope
A concept map, not a specific diagnosis or surgical stage. “Single ventricle” means one ventricle does the effective pumping work, not necessarily only one anatomical ventricle.
Original Heart Up Close connection map · Source check: 26 October 2026 · Independent clinical review pending.
Single ventricle circulation
- Body and lung blood return. Less-oxygenated blood returns from the body, and oxygenated blood returns from the lungs.
- One dominant pumping ventricle. In this concept map, both returns reach one effective main pump. The exact chamber connections differ between diagnoses.
- The pump supports both destinations. The circulation needs blood to reach both lungs and body. The balance varies with the individual connections and resistance.
A concept map, not a specific diagnosis or surgical stage. “Single ventricle” means one ventricle does the effective pumping work, not necessarily only one anatomical ventricle.
02
Diagnosis and care
Diagnosis and tests
The underlying heart difference may be found during pregnancy. It may be found after birth when a baby has low oxygen levels or other signs of illness. The timing depends on how the heart is formed. During pregnancy, ask how the temporary blood-flow routes support the baby and what will change at birth.
An echocardiogram, or echo, is an ultrasound scan of the heart. It shows the chambers and routes for blood. Oxygen levels and growth help the team see the day-to-day effects. MRI gives more detailed pictures. A catheter test passes a thin tube through a blood vessel towards the heart to measure pressures or check blood flow.
These tests may help decide whether another stage of treatment is suitable. No one test answers every question.
Care and follow-up
Care often involves several operations. An early procedure may change blood flow to the body or lungs. A Glenn-type operation sends blood returning from the upper body directly to the lungs. A Fontan-type operation sends the remaining blood returning from the body towards the lungs too. The ventricle then pumps to the body. The stages and whether each is suitable depend on the child.
This blood-flow arrangement still differs from a two-pump heart. It needs lifelong specialist checks. Not every child can have the same stages. The valves, the main pumping chamber, the blood vessels in the lungs and other health needs all matter. Ask how blood flows now, what the next step aims to change and what remains uncertain.
Daily life
Between operations some babies have a structured home monitoring programme. Ask whether this is needed, what training you will receive and who responds to concerns. Use your own team’s plan. Ask which measurements mean you should get help. Little Hearts Matter offers support for single ventricle families.
03
Questions to ask
Save the questions you want to take to your next appointment. You can edit them in your Journal.
- What is the full name of our child’s heart condition, and could you explain their particular heart arrangement on a drawing?
- How does blood reach our child’s lungs and body now, and what is the team most concerned about at this stage?
- What would the next stage of treatment change, and what are its main aims for our child?
- Does our child need home monitoring, and can you give us a written plan for measurements, concerns and contacts?
- What support can help our child at school, and how will care be planned as they approach adult services?
Sources and review
Sources checked 9 October 2026. Independent clinical review pending.
- Great Ormond Street Hospital: Conditions treated by the Single Ventricle Service
Accessed 9 October 2026
- Little Hearts Matter: The Fontan procedure
Accessed 9 October 2026
- Nemours KidsHealth: The Glenn Procedure
Accessed 9 October 2026
- Great Ormond Street Hospital: Single Ventricle Service Home Monitoring Programme
Accessed 9 October 2026
- Great Ormond Street Hospital: Charities and Support
Accessed 9 October 2026