Atrioventricular Septal Defect (AVSD)

The aim of this fact sheet is to explain what Atriventricular Septal Defect (AVSD) is, what effect it will have on a child and how it can be treated.

What is Atrioventricular Septal Defect?
Atrioventricular means of the atria and the ventricles the four chambers of the heart.
Septal means of the septum the wall between the left and right sides of the heart.
Defect means hole.

So Atrioventricular Septal Defect means there is a hole between the atria atrial component which continues down between the ventricles ventricular component. There is a single common valve, instead of a mitral valve on the left, and a tricuspid on the right. This means that there is a large hole in the middle of the heart.

Because pressure is higher on the left side of the heart, blood flows from the left atrium into the right, and from the left ventricle into the right. This means that far too much blood is moving at high pressure into the pulmonary artery and the lungs.

Often the common valve leaks either into the left or right side atrium or both. This makes the heart work very hard, increasing pressure still further into the lungs.

AVSD can be partial and intermediate as well as the complete AVSD shown above:

In intermediate AVSD there is a small ventricular component.

In partial AVSD there is only an atrial component and there are two valves, although the mitral valve is deformed and often leaky.

Diagnosis
AVSD can be diagnosed during pregnancy: the cross at the centre of the heart, formed by the valves and septum, which should be seen on an ultrasound scan of the babys heart, is missing.

If your child has Downs Syndrome, his or her heart may have been examined to check for AVSD which occurs in nearly a quarter of children with this syndrome.
If your childs heart condition is very complex AVSD may be just one of a number of defects.

After birth your baby may be blue and may gradually become breathless, have problems feeding, may be slow putting on weight and fail to thrive. She or he may have frequent chest infections. The sound of extra blood being pushed towards the lungs and leaking through the valve can be heard as a heart murmur.

If your baby has the partial or intermediate form of AVSD there may not be any symptoms early in life, other than a heart murmur.

When a heart murmur is heard the tests used can be:

an ultrasound scan (echocardiogram) to see the hole and how the blood moves through the heart
an oxygen saturation monitor to see how much oxygen is getting into the blood
a chest x-ray to see the size and position of the heart
an ECG (electrocardiogram) to check the electrical activity
checks for chemical balance in blood and urine
pulse, blood pressure, temperature, and number of breaths a baby takes a minute
listening with a stethoscope for changes in the heart sounds.

At home
You may be at home while your baby grows stronger for surgery.

You, your GP and Health Visitor should have details of your babys condition from the heart doctor (paediatric cardiologist). If not, call the hospital at which your baby was treated, ask for the name of the paediatric cardiologist and their telephone number. Call and explain that you need the information to pass on to, for example, your local casualty Department should he or she have a sudden illness.
You should have the number of a cardiac liaison nurse or outreach nurse to call should you have questions or any fears about your babys heart problem.
You should have the number of a parent support group.

Treatment
If the heart is not coping, you may be told your baby is in heart failure. This can mean that the lungs and other organs become heavy or wet with fluid and your baby does not pass very much urine. A careful check will be kept on the babys weight as an increase can be due to fluid retention. He or she may need medicines to get rid of the extra fluid diuretics.
If your baby has a complete AVSD, there will be pulmonary hypertension (high pressure of blood in the lung arteries), and an operation will be needed before irreparable damage is caused to the lungs.

This is open heart surgery the heart will need to be stopped and opened to repair it. This means that a machine will have to take over the job that the heart normally does the heart bypass machine.

The aim of the operation is to make the circulation of blood through the heart and lungs normal, so a patch is put over the holes between the atria and ventricles, and the valve is divided, so that there are two effective valves.

If your child has other heart defects, the kind of surgery needed will depend on how the heart can best be modified to cope with all the problems he or she has.

For most children this surgery is low risk, but it can depend on how well your child is otherwise. The doctors will discuss risks with you in detail before asking you to consent to the operation.

The length of time in hospital will usually be only 10 to 12 days, of which one or two will be spent in the intensive care and high dependency unit. Of course this depends on how well your child is before and after the surgery, and whether any complications arise.

How it affects your child
If the surgery is straightforward, and your child does not have other health problems, he or she should be completely well shortly after surgery. There will be a scar down the middle of the chest, and there may be small scars where drain tubes were used. These fade very rapidly in most children, but they will not go altogether. Smaller scars on the hands and neck usually fade away to nothing.

Most parents are amazed at how quickly the baby recovers from surgery and starts to gain weight.

Some of these problems can occur after surgery or later in life:

It is common for the valves to leak a little, but if this becomes severe, they may need further repair or even replacement with an artificial valve. If this happens the child will need to take an anticoagulant medicine to stop blood clots forming. The anticoagulant effect has to be monitored frequently using a blood test.
Because it is close to the site that the surgeon is working, the electrical system of the heart is sometimes damaged, causing a slow heartbeat, called heart block. This may need to be corrected by giving the child a pacemaker.
Some people go on to develop sub-aortic stenosis, a blockage below the aortic valve, which may need open heart surgery.
Hearts that are not normal are more likely to have an infection called endocarditis. Although rare this is a difficult disease to treat.

People born with an AVSD will need to take antibiotics if there is a chance that a large number of bacteria will get into the blood stream. The most common way for this to happen is during ear-piercing or tattooing, or surgery or a dental procedure such as de-scaling of teeth or an extraction.

These problems may not become serious until the teen years or adulthood.

Parents stories

Alice
I knew Alice had an AVSD before she was born. We were offered the test for Downs syndrome, but we decided against it it was obvious that she had Downs as soon as I had my first look at her.

It was a normal birth and she was taken to Special Care Baby Unit as soon as she was born. We had some problems getting her to feed but we were sent home to fatten her up for surgery. That was very worrying time I was more worried about her heart problems than the Downs Syndrome. The childrens hospital where she was treated for her heart had special nurses who you could ring about problems, and when Alice started to have real difficulties feeding, we had a visit from one of them.

Of course, I also relied heavily on my GP and Health Visitor. The best source of support and information was the Downs Heart Group, and we met families who had been through all this before.

Alice was seven months old when she had surgery I was looking forward to it as she had become really poorly, finding it difficult to take her feeds and then to keep them down. But handing her over for the operation was the worst moment worse even than hearing about her heart.

She sailed through it but the pressures stayed high in her lungs, so she stayed in hospital for longer than we expected. Apart from a little leak that the hospital keeps and eye on, Alice hasnt had any further heart problems. She loves to show off her scar which you can hardly see to anyone she thinks may be interested!

Dan
Dans AVSD wasnt discovered until close to his second birthday his cardiologist
said this was because the VSD was very
small. He had surgery when he was three, but he didnt recover well. He put on a lot of weight around his middle despite vomiting after most meals, and was so tired most of the time that his nursery school said they could no longer have him.

About eighteen months after the surgery, his cardiologist found that he had heart block a very low heart rate and his mitral valve was leaking a lot. He had high pressure in his lungs and his heart was very enlarged. He was in congestive heart failure. We relied heavily on Dans Aunts to look after our other children during this time, and joined our local parent support group, to which we still belong.

He spent some weeks in hospital on diuretics to remove the excess fluid from his organs. Then he had surgery and the mitral valve couldnt be repaired so he had an artificial one put in. To keep his heart rate up, he was given a pacemaker.

The difference this made to him was amazing although he didnt recover his appetite for most foods. He lost some skills he had before surgery, such as writing his name and reading, but these recovered with help after a year or so.

As he got older he developed sub-aortic stenosis which is quite rare. At sixteen he had open heart surgery to remove the membrane growing across his aortic valve removed.

Now he just needs an annual check-up - Dans biggest problem has been dealing with the warfarin he needs to take to stop clots developing, and the effect this has had on his chances of playing football. He has also become very conscious of his scars, but no one would guess seeing him in the street that he has had so many problems.

Please contact CHF if you have suggested amendments or changes as we like to keep our information sheets relevant and up-to-date.