Your child’s diagnosis
Ventricular septal defect (VSD)
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How blood flows
Ventricular septal defect (VSD)
The same region in both views. The usual view is a comparison, not a treatment result.
VSD · a connection between ventricles
- Less oxygen
- Mixed blood
- More oxygen
Step 1 of 3
An opening between the pumps
A VSD is an opening in the septum between the left and right ventricles. Locate the gap between LV and RV.
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.
Simplified isolated defect after birth, showing the common left-to-right pattern after lung resistance falls. Flow amount and direction vary with opening size, pressures, lung resistance and other anatomy; newborn transition and reversed shunts are not shown. Colours show relative oxygen content, not measured saturation.
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.
Diagram sources and scope
Simplified isolated defect after birth, showing the common left-to-right pattern after lung resistance falls. Flow amount and direction vary with opening size, pressures, lung resistance and other anatomy; newborn transition and reversed shunts are not shown. Colours show relative oxygen content, not measured saturation.
Original Heart Up Close connection map · Source check: 26 October 2026 · Independent clinical review pending.
Ventricular septal defect (VSD)
- An opening between the pumps. A VSD is an opening in the septum between the left and right ventricles. Locate the gap between LV and RV.
- Some blood crosses from LV to RV. In this common pattern after birth, higher pressure in the LV pushes some oxygen-rich blood through the opening into the RV. The usual LV-to-body route also remains open.
- The RV sends extra blood to the lungs. The blood that crossed joins blood in the RV and travels to the lungs again. A larger shunt can increase lung blood flow; the arrow does not show its size.
Simplified isolated defect after birth, showing the common left-to-right pattern after lung resistance falls. Flow amount and direction vary with opening size, pressures, lung resistance and other anatomy; newborn transition and reversed shunts are not shown. Colours show relative oxygen content, not measured saturation.
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Diagnosis and care
Diagnosis and tests
Some VSDs are seen on a pregnancy scan. Others are found after a doctor or nurse hears a murmur, an extra sound during the heartbeat. A murmur alone does not show how serious the opening is. Babies with a larger VSD may tire during feeds, breathe quickly or gain weight slowly. Some children have no noticeable symptoms.
An echocardiogram, or echo, is an ultrasound scan of the heart. It shows the opening and blood flow. The team may check growth, breathing and oxygen levels too. An ECG records the heart’s electrical signals. Other scans may answer particular questions. A catheter test passes a thin tube through a blood vessel towards the heart. Ask what each test adds and how to prepare.
Care and follow-up
A small VSD may close as a child grows. It may stay open without needing treatment to close it. Regular checks show its effect on the heart. Medicines and feeding support may help if extra blood flow causes difficulties. Some children need an operation to close the opening, usually with a patch.
Some VSDs can be closed with a device passed through a thin tube, called a catheter. The choice depends on how the child’s heart is formed.
The opening’s size is only part of the picture. Its position, its effect on valves and blood pressure in the lungs also matter. Other conditions may change the plan. Checks may continue after repair to look for any remaining opening or changes in how well the heart works. Another family’s story may help you feel understood. It cannot predict your child’s care.
Daily life
Ask the team how the diagnosis affects feeding, nursery, school, play and recovery from treatment. Request a clear contact plan and a written explanation you can share with other carers. You can ask whether there are any activity precautions and when they should be reviewed.
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Questions to ask
Save the questions you want to take to your next appointment. You can edit them in your Journal.
- Could you show us where the opening is and explain whether it affects any of the heart valves?
- What does the scan tell you about the extra blood flow, and what does that mean for our child?
- What changes would make you recommend closing the opening rather than continuing to monitor it?
- How will you check our child’s feeding and growth, and what should we keep track of at home?
- Who should we contact between appointments if we notice changes or have questions about our child’s care?
Sources and review
Sources checked 9 October 2026. Independent clinical review pending.
- Great Ormond Street Hospital: Ventricular septal defect (VSD)
Accessed 9 October 2026
- British Heart Foundation: Ventricular septal defect (VSD)
Accessed 9 October 2026
- Children’s Heart Federation: Ventricular Septal Defect (VSD)
Accessed 9 October 2026