Cardiac problems in babies with Down’s syndrome explained

Posted: 17/03/2015

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At around 20 weeks gestation all women are offered an ultrasound scan, known as the ‘anomaly’ scan. The purpose of this scan is to check for structural abnormalities in the baby. One of the organs carefully checked during this scan is the heart. This scan may highlight heart defects in the baby which can then be investigated with a more detailed scan known as a ‘fetal echocardiogram’.

In some cases, this leads to a diagnosis of Down’s syndrome before a baby is born. When this happens, parents will be informed about the treatment that their baby will need. They may also consider the option of ending the pregnancy.

Half of babies born with Down’s syndrome will also have a heart condition. Accordingly, when a baby is diagnosed with Down’s syndrome, their heart will be carefully assessed to detect and treat any problems as soon as possible.

The most common heart defects identified in Down’s syndrome babies are:

• An atrioventricular septal defect (AVSD) – there is a hole between the atria and between the ventricles. The one atrioventricular valve often leaks either into the left or right atrium or both. This makes the heart less efficient than normal so it has to work harder to function.
• A ventricular septal defect (VSD) - failure of development of the septum between the two heart ventricles. When the hole does not close, it may cause higher pressure in the heart or reduced oxygen to the body.
• Secundum atrial septal defects (ASD) – there is an abnormally large opening in the atrial septum which results in left to right shunting of blood.
• Persistent ductus arteriosus (PDA) - the ductus arteriosus is a normal foetal blood vessel that closes soon after birth. In a PDA, the vessel does not close resulting in irregular transmission of blood between two of the most important arteries close to the heart.
• Tetralogy of fallot - this is a rare condition caused by a combination of four heart defects that are present at birth causing oxygen-poor blood to flow out of the heart and into the rest of the body.

It is very important that these conditions are identified as soon as possible. Early examination may reveal a heart murmur or later signs can include slowing growth or signs of heart failure such as poor feeding and breathing difficulties. Once the condition is identified, an informed treatment plan can be started.

If a congenital abnormality is not identified early enough (particularly if this is an AVSD), this can lead to the development of pulmonary hypertension. This is particularly significant in those with Down’s syndrome as they are at a higher risk of this developing. Pulmonary hypertension makes it impossible to operate to correct the original congenital defect and conservative management is then the only way forward.

In this situation the patient may go on to develop Eisenmenger Complex. This is the term used to describe the prolonged effects of pulmonary hypertension in patients with uncorrected heart defects, which eventually leads to a reversal in the shunting of the blood within the heart.

Eisenmenger Complex is a very serious condition. A patient suffering from this can experience ‘blue spells’, dizziness and fainting, breathlessness and chest pain. They can be prone to suffering small strokes or coughing up blood. Eisenmengers is a life-limiting condition and therefore it is extremely important to identify and treat congenital heart defects while there is an opportunity to do so and before pulmonary hypertension occurs.

Congenital heart defects should be identified promptly as there are serious consequences if they are not. The patient loses the opportunity to undergo surgery and is left with significant treatment needs which, as well as being distressing and painful for the patient and their family, are a significant cost to the NHS in ongoing treatment needs. These may include the use of oxygen, venesection (the draining of blood to decrease the presence of red blood cells), and the use of various medications to manage the symptoms, some of which are very expensive.

Helen Hammond, an associate in the Penningtons Manches clinical negligence team, comments: “Babies born with Down’s syndrome 20 years ago are more likely to have developed Eisenmenger Complex, as it was more commonplace at that time not to operate on a child with Down’s syndrome with a congenital heart defect due to the risks of surgery. With modern advances in treatment and surgery, the development of Eisenmenger Complex, while not avoidable, should be a much rarer occurrence.”

If your child has recently been diagnosed with a heart condition and you would like some help and support, you can contact the Down’s Heart Group (www.dhg.org.uk), a charity that specialises in providing support and information to individuals with Down’s syndrome and associated heart conditions and their families.

If you have any concerns that your child’s heart condition should have been diagnosed sooner - either before they were born or more quickly after their birth) it may be possible to pursue a claim to compensate them for the pain, suffering and injury that they suffered.

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