Learning that your baby has a complex heart problem can be frightening and leave you feeling very alone.

Over the following pages we hope to help you understand how a diagnosis is made and answer some of the common questions a diagnosis creates. If at any time you would like to chat through the information you have been given, do not hesitate in giving the LHM team a ring on 0121 455 8982.


How the diagnosis of single ventricle heart disease is made

There are two main opportunities for a diagnosis of complex heart disease to be made – either before or after birth.

Antenatal diagnosis

In many cases it is now possible to make a diagnosis of a single ventricle condition when a pregnant woman undergoes her 16 – 20 week ultrasound scan. Scans before this stage of the pregnancy are unlikely to detect problems because the baby’s heart, lungs and other organs are not big enough to be seen clearly.

A sonographer (the member of staff who scans mothers to look at the baby) will be looking to see that the baby’s heart has four chambers, and two major crossing blood vessels leaving the heart. If there is any doubt that the baby has a normal heart or other organs the sonographer will seek a second opinion from the obstetrician or fetal medicine doctors (doctors who specialise in looking at unborn babies).

If a problem with the heart is seen clearly, the obstetric team will refer the family to a specialist in this field, a fetal cardiologist (a heart doctor who specialises in looking after unborn babies). If a complex condition is confirmed, the cardiologist and the obstetric team will talk to the family about the diagnosis and the possible treatments. They will offer further tests, such as amniocentesis, to see if the baby has any unseen problems with their genetic picture (to see if the blueprint of the baby has a fault – for example, something like Down’s syndrome). For more information on antenatal tests speak to your midwife.

Once all of the tests have been completed the family will be given the opportunity to discuss the future for their child. The team will support the family whilst they make their decision either to continue with the pregnancy or to end the pregnancy through termination.

Most babies with a single ventricle condition grow well in their mother’s womb. They are usually born between 38 and 40 weeks of pregnancy. It is only after birth, once their fetal circulation changes (see Fetal Circulation) that their defects begin to affect their bodies.

For more information on antenatal diagnosis refer to Antenatal Information.

Postnatal diagnosis

As long as the ductus arteriosus remains open, it is often difficult to detect that a newborn baby has a problem with its heart. (See Fetal Circulation).

As the ductus arteriosus closes the baby will become breathless and sweaty, sleep more and drink less milk. This can happen while the baby is still in hospital and may be detected by the midwife or doctor as they do their post-delivery checks or within a few days of going home when the midwife or health visitor should notice that the baby needs to see a doctor.

Once the baby has been referred to a paediatrician (baby doctor) tests will be done to try and find out what is causing the problem. Medicine called Prostaglandin will be given to the baby to try and keep the ductus arteriosus open, as this will keep the baby alive until treatment decisions can be made. (See Fetal Circulation).

The baby will be transferred with a medical team to the nearest hospital that treats congenital heart defects. Here the baby will have an ultrasound scan (echocardiogram or echo) similar to the scans done in pregnancy. The specialist heart team will be able to see what the heart looks like and will be able to make a diagnosis.

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Questions commonly asked at time of diagnosis

What causes the heart to form this way?

As yet the causes of single ventricle heart conditions are unknown. It cannot be linked with mild drinking or the taking of ‘over the counter’ or most prescribed medications.

There are some indications that it can be linked to heavy smoking, alcohol or drug abuse, and anyone with diabetes has an increased risk of having a child with a heart condition.

It is very likely that one or more abnormalities are present before the third month of pregnancy but they may become more obvious as the heart is growing through the last part of the pregnancy.

Heart abnormalities can be present in babies that have other congenital problems, for example, genetic disorders like Down’s syndrome or Di-George syndrome (22q Deletion).

Why was the problem not detected during pregnancy?

It is possible to detect single ventricle heart disease during pregnancy but it may not be obvious during scans due to the size or position of the baby. In some cases the condition can become more evident later in pregnancy after the routine scans have been performed. (See Antenatal Diagnosis).

Can my baby have treatment anywhere in the country?

Over the past few years, an increasing number of centres around the country have begun offering surgery for these conditions, but not all, so it may be necessary for your baby to move hospital to receive treatment.

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The normal heart



In order to understand what a complex heart condition means, it is helpful to understand what the normal heart does. The heart’s job is to pump blood around the body. There are two separate circulations: the first takes blood to the lungs (the right side of the heart), and the second takes blood to the body (the left side of the heart).

This is how the journey begins: blood returns from the body, via veins, to the right side of the heart into a collecting chamber called the right atrium. This blood has a bluish tinge (blue blood) because the body has extracted oxygen from it (deoxygenated blood).

The blood is then passed through a valve (tricuspid valve) to a pumping chamber (right ventricle), which pumps the blood to the lungs via the lung arteries (pulmonary arteries).

The blood picks up oxygen as it passes through the lungs which turns the blood a red colour (oxygenated blood). This blood then returns to the left collecting chamber (left atrium) and it then passes through a valve (mitral) to the left pumping chamber (left ventricle). The left ventricle then pumps blood to the body through a valve (aortic valve) and to the body via the body artery (aorta). The body uses the oxygen from the blood, turning it blue again. And the journey starts again.

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The circulation before birth (fetal circulation)



When the baby is still in the mother’s womb it does not need to breathe for itself as the mother is supplying all the oxygen to the baby via the umbilical cord.

The circulation before birth is different from that after birth. It is designed so that the oxygen-filled blood from the umbilical cord goes to the most important parts of the body, for example, the brain. Very little blood needs to go to the lungs.

There is a hole between the upper two collecting chambers (the left and right atrium) called the foramen ovale. Oxygen-filled blood from the umbilical cord is directed to the right collecting chamber (right atrium) and passes to the left collecting chamber (left atrium) through the hole and then on into the left pumping chamber (left ventricle), from where it is pumped around the body.

There is also a connection between the lung artery (pulmonary artery) and the body artery (aorta) called the ductus arteriosus (duct). Blood passes from the right pumping chamber (right ventricle) into the lung artery (pulmonary artery). Some of this blood then passes to the lungs.

When the baby is born and starts to breathe for itself, the bypass systems are no longer needed. Gradually over the first few days or weeks after birth, the duct (ductus arteriosus) and the hole (foramen ovale) between the upper two pumping chambers will close off and the baby’s circulation will be as described earlier. (See Normal Heart).

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Possible treatment choices

Having explained your child’s diagnosis, the doctor will go on to discuss what treatments are available. None of these treatments provide a long-term cure but, for many children, they can offer a reasonable quality of life.

It is vital that parents are fully included in the treatment discussions and decisions taken for their child.

These treatment options may include:

Surgical treatment

The aim of this treatment is to re-route the blood through the right side of the heart, bypassing the blockages on the left side. This surgery is offered in three stages over three or more years and involves extremely high-risk open-heart surgery. Your doctors will explain the risks for your child. Even after all the surgery has been performed, your child’s heart will not look normal or work normally, and it may be that it will gradually fail and your child may need a heart transplant in teenage years or early adult life. More information on the surgery follows.

Supported comfort care

As the long-term outcome is unclear for children with Hypoplastic Left Heart Syndrome, it is important to know that there is the option not to put a child forward for surgery. The baby is allowed to die peacefully either in the hospital or at home; the family would be fully supported by hospital and community nursing and medical staff.


Heart transplantation is one of the possible treatments for single ventricle heart disease, but it is not offered as a first treatment within the United Kingdom for the following reasons.

There are very few donor hearts small enough for a baby available in the United Kingdom.

Transplanted hearts do not last for ever and there are many risks involved throughout the recipient’s life. Offering surgery as a first treatment path and retaining transplant as a future option offers a greater chance of a longer life for a child.

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Many families who have a child with congenital heart disease ask why their child was born with the condition. In some cases the malformation will have occurred because of a genetic problem that has affected the heart as it formed in the womb.

A blueprint

When a new house is built the architect draws up a plan of what the house will look like and how it is going to be built.

When a new child is being created, information is drawn from the mother and the father to make a plan of how the child will look and how its body will be put together to work.

A genetic blueprint

Every person in the world has a genetic blueprint of their own. The blueprint is stored in every cell in their body and holds the information required to help the body grow, develop and work properly. The information is made up of lots of messages which we call genes. We have about 30,000 genes in each cell of our body. Different genes have different messages that are responsible for instructing our body to do specific things. For instance, genes determine the colour of our hair or eyes or how cells work in different organs, for example, the liver, heart or lungs. It is our very own information computer.

The genes are stored in coils and split into chromosomes. Humans have 23 pairs of chromosomes, so 46 in total. 23 chromosomes (one of each pair) come from the mother and the other 23 from the father. They are transferred in the egg and the sperm that make a child.

The picture below shows what the chromosomes look like – if you look at the last set of chromosomes in this picture you will see that they are labelled X and Y. These are the chromosomes that decide if you are male or female. The chromosomes below must come from a man because there is an X and a Y chromosome. A woman has two X chromosomes.




Genetics and heart disease

Some congenital heart conditions are linked to a genetic disorder such as Down’s syndrome or 22q Deletion. These disorders are caused when one of the 46 information chromosomes is malformed. As the baby grows in the womb, the genetic malformation will cause a particular part of the heart to develop incorrectly. In some cases the genetic condition can be detected before birth.

Geneticists (genetics doctors) are always looking for genetic causes for congenital conditions; however, there are many heart conditions that do not have a specific genetic cause. Many of the single ventricle heart conditions fall into this group.

There may be many factors, as yet unknown, that cause a baby’s heart to develop abnormally. The problems can occur early in pregnancy as the heart forms or later as it grows.

Congenital heart conditions occur in 1 in 100 pregnancies. If you have previously had a child with a single ventricle heart problem, the risks of it happening again to parents, their other children or the child affected themselves rises to between 5 and 8%. Although the risk is higher, over 90% of future babies will not have a problem with their heart.

Updated: June 2017

Review due: June 2019

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