Congenital heart disease - septal defects factsheet


Congenital heart disease is the name used for a difference or problem with how a baby’s heart has grown during pregnancy. 

The heart is made up of four chambers:

  • left and right atria, at the top
  • left and right ventricles, at the bottom.

The septum is a wall of tissue that separates the left and right sides of the heart.

A septal defect is a type of congenital heart disease where there is a hole in the septum. 

There are three common types of septal defects:

  1. atrial septal defect (ASD) - a hole between the left and right atria at the top
  2. ventricular septal defect (VSD) – a hole between the left and right ventricles, at the bottom  
  3. atrio ventricular septal defect (AVSD) – holes between all four chambers of the heart.

A hole in the septum means that a larger amount of blood flows towards the lungs. Over time this can damage the blood vessels in the lungs and cause problems with the heart.  

 Signs and symptoms

Septal defects can range from small to large. Most children with a smaller septal defect will look healthy they may not show any signs or symptoms until they get older.

Children with a larger septal defect, or one that has been left untreated for a long time, can have symptoms like:

  • difficulty breathing
  • running out of breath quickly when doing activities or exercise
  • getting tired quickly when feeding from the breast or bottle
  • frequent respiratory or lung infections, like pneumonia
  • skipping heartbeats
  • a whooshing sound in the heart, also known as a heart murmur
  • swelling in the legs, feet, or belly.

Children with larger or untreated septal defects have a higher risk of stroke. 

A stroke is when blood cannot get to the brain properly because of a blockage or bleeding. A stroke can cause: 

  • brain damage
  • permanent disability
  • death. 


A septal defect can be diagnosed with an ultrasound scan during pregnancy. 

Some babies will be diagnosed when they are born, others may not be diagnosed until they are older.

To diagnose a septal defect, your local doctor will refer you to a heart specialist, called a cardiologist.

The cardiologist will use a test called an echocardiogram to get an image of your child’s heart. This image will show how well the blood moves through the heart, and will tell the doctor:

  • what type of septal defect it is
  • how big it is
  • where it is
  • how severe it is
  • whether your child has any other heart issues.


Most septal defects are diagnosed and treated successfully.

Septal defects can be treated with:

  • watching and waiting
  • medication for symptoms
  • surgery to repair.

Treatment will depend on:

  • how old your child is
  • the signs and symptoms they are showing 
  • how severe their symptoms are
  • the size of the hole
  • whether your child has any other health conditions. 

Septal defects that are found early may be treated with medication to manage symptoms while waiting to see if the hole closes on its own.


There are two common procedures used to close a septal defect:

  • cardiac catheterisation 
    • a tiny tube or catheter is inserted into a blood vessel in your child’s groin and pushed through to the heart 
    • a device is passed through the tube and used to plug the hole
    • the tube is removed, and heart tissue grows around the device. 
  • open heart surgery
    • the chest wall is opened up
    • the surgeon stitches or patches the hole directly. 

The procedure used for your child will depend on the type of septal defect they have, and how severe it is.

Your child’s doctor will talk to you about the procedures, what they involve and the time it will take for your child to recover.

Most children who have surgery will recover quickly. Your child will have ongoing check-ups with their cardiologist to make sure their heart is still working well and there are no other problems. 


When to seek help

See your local doctor or your child’s cardiologist if they show any signs like:

  • poor appetite
  • trouble with feeding or eating
  • a decrease in activity levels
  • fever that lasts longer than 72 hours.

Call Triple Zero (000) for an ambulance, or go to your nearest emergency department if your child has:

  • trouble breathing
  • chest pains
  • increasing pain and tenderness around their surgery wound
  • pus or blood coming from their surgery wound.
Last updated Tuesday 30th April 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024