Congenital heart disease

Congenital heart disease is a general term that covers all heart defects children are born with. The word congenital means the condition is present at birth.

Congenital heart defects are usually due to something disrupting the complex development of your baby’s heart in the first 6 weeks of their development in your womb. It is not clear what disrupts this process, but some things can increase your baby's risk. 

These include the following:

• Your baby having Down syndrome – a genetic condition caused by having an extra chromosome. Read more about Down syndrome.
• Your baby having Turner syndrome – a genetic condition that affects the sex chromosomes.
• Your baby having Noonan syndrome – a genetic condition that affects normal development of the body.
• Having pre-existing diabetes when you get pregnant.
• Drinking alcohol when you are pregnant or your baby having foetal alcohol syndrome.
• Getting rubella (German measles) virus when you are pregnant. This virus can damage the developing heart, so it is important to get vaccinated against rubella with the MMR vaccine at least 1 month before you get pregnant. If you come into contact with the virus in the first 3 months of your pregnancy, contact your lead maternity carer (LMC) or your doctor.
• Getting the flu when you are pregnant – it is unclear why pregnant women who get the flu during the first trimester of pregnancy have a higher risk of having a baby with congenital heart disease, but it is important you get vaccinated against the flu when you are pregnant.
• Some medicines are known to cause congenital heart disease in babies or increase your risk of having a baby with congenital heart disease. Examples include diazepam, isotretinoin, topical retinoids or ibuprofen. Don’t take any medicine when you are pregnant unless it is recommended by your doctor. Talk to your doctor, lead maternity carer (LMC), midwife or pharmacist if you are unsure.
• Having phenylketonuria (PKU) , a rare genetic condition present from birth. In this condition, your body can't break down a chemical called phenylalanine, causing it to build up in your blood and brain.

Your heart pumps blood around your body. It is separated into left and right sides by a muscle called the septum. The left side of your heart pumps blood containing oxygen through your main artery (the aorta) to other parts of your body. Tissues in your body, such as your muscles, brain and kidneys, use some of the oxygen in your blood, leaving it with a blue tinge.

The ‘blue’ or deoxygenated blood returns through your veins to the right side of your heart, which pumps it through the pulmonary arteries to your lungs. In your lungs, your blood gets oxygen again, restoring its red colour, and it returns to your heart ready to be pumped once more through your body.

In your heart, there are 4 main chambers, ie, the left atrium, the left ventricle, the right atrium and the right ventricle.

• The atriums are called receiving chambers as they receive blood either from your lungs or other parts of your body.
• The ventricles are called pumping chambers as they pump blood to your lungs or other parts of your body.
• Your left atrium and ventricle are separated from your right atrium and ventricle by a muscular partition called the septum.
• Both your atriums are also separated from the ventricles on their side by structures called valves.
• There are also valves between your ventricles and your major blood vessels such as the aorta and pulmonary artery.
• These valves are important in keeping blood flow in the proper direction.
• The right-sided valves are called the tricuspid and pulmonary valves and the left-sided valves are called the mitral and aortic valves.

There are more than 40 different types of heart defects. The main heart defects include:

• problems with heart valves
• problems with blood vessels
• holes in the heart
• a mixture of defects.

Problems with heart valves

In some types of congenital heart disease, there can be problems with heart valves not forming or working properly. You can either have:

• stenosis, which is a significant narrowing of your heart valves, or
• regurgitation, which means your valves not closing properly.

When your heart valve is narrowed, your heart has to work a lot harder to pump blood through the narrowed valve. An example of this is aortic valve stenosis. When your heart valve doesn't close properly, it can let blood flow back or leak into the heart chamber, which puts extra load on your heart.  

Problem with blood vessels

Problem with blood vessels can include coarctation (abnormal narrowing of your blood vessel), which means less blood can flow through. An example of this is coarctation of the aorta. Sometimes the coarctation is so severe that surgery is needed to correct the defect shortly after birth.

Holes in the heart 

Holes within the heart may occur in the muscular partition between your atriums or the partition between your ventricles. These holes allow an abnormally large amount of blood to flow into the right side of your heart and through your lungs. This means not enough blood with oxygen is pumped around your body. Examples of this include atrial septal defect or ventricular septal defect.

Another defect is patent ductus arteriosus, where a duct called ductus arteriosus doesn’t close normally. Before birth, there is a duct or channel between the aorta and pulmonary artery to allow blood to bypass the lungs, as the lungs have no function while your baby is still in your womb. This channel normally closes at birth, but if it doesn't the effect is similar to that caused by a hole in the heart.

A mixture of defects 

Babies can be born with a mixture of several defects, such as a hole in the heart, problems with heart valves and heart vessels, and a thickening of heart muscle. When these defects are combined it can be complicated, as ‘blue’ and red blood can mix in your heart. This means there isn’t enough oxygen in your baby's blood to be pumped throughout their body. This can cause your baby to appear blue (cyanosis).

An example of a condition with combined defects is Tetralogy of Fallot, which includes defects such as:

• ventricular septal defect – a hole between your left and right ventricle
• pulmonary valve stenosis – your pulmonary valve is narrowed
• right ventricular hypertrophy – the muscle of your right ventricle is thickened as it needs to work harder
• overriding aorta – the aorta is not in the right position coming out from your heart.

Some of the severe defects cause symptoms soon after birth, while mild defects may only cause symptoms later as a child or an adult.

If your child has congenital heart disease, symptoms or signs can include:

• being blue or a having blue tinge to their skin, lips or fingernails (cyanosis)
• fast breathing
• your doctor hearing a heart murmur through the stethoscope
• fast heartbeat
• swelling in their legs or tummy or around their eyes
• shortness of breath when feeding or exercising (in children or adults)
• excessive sweating
• tiredness and fatigue
• difficulty gaining weight
• fainting during exercise (in children and adults)
• not growing well (children)
• frequent infections
• swelling in the hands, ankles or feet.

If you or your child has congenital heart disease, further problems can happen, including:

• problems with growth and development
• frequent respiratory tract infections (RTIs)
• infective endocarditis (a heart infection)
• pulmonary hypertension – increased blood pressure in the blood vessels of your lungs
• heart failure – when your heart fails to pump blood efficiently.

In most cases, congenital heart disease is diagnosed during pregnancy, but it may only be diagnosed after birth.

Diagnosis during pregnancy

During pregnancy, congenital heart disease can be detected during the ultrasound scan at around 18–22 weeks, also known as the anatomy scan. If your doctor suspects your baby has a congenital heart disease, they will refer you for further testing, such as a foetal echocardiography (ultrasound scan of the heart) to specifically scan the heart of your baby to confirm the diagnosis. However, it is not always possible to detect heart defects using foetal echocardiography if the defect is mild.

Diagnosis after birth

Your doctor can diagnose congenital heart disease after your baby is born if they show symptoms such as being blue around their skin or lips, swelling in their tummy or around their eyes, or shortness of breath when feeding. Your doctor will check your baby’s heart as part of the newborn and 6-week check examinations. If your baby doesn’t have any symptoms, a heart exam can sometimes pick up murmurs, which may be a sign of congenital heart disease.

Depending on what your doctor thinks is causing the symptoms, further testing may be needed, including:

• a chest x-ray
• echocardiography
• electrocardiography (ECG)
• cardiac catheterisation – this procedure involves passing special tubes through an artery or vein to take recordings and x-rays of the heart under anaesthetic.

In some types of congenital heart disease, symptoms don’t show up until later as a child or an adult. 

Treatment depends on the type and severity of congenital heart disease you or your child has. You or your child will also be referred to a cardiologist (a heart specialist doctor) for treatment. Treatment of congenital heart disease has improved dramatically over the last 30 years and there are now many treatment options available.

Treatment can include the following:

• Self-care measures – you or your child may need to avoid strenuous exercise or get vaccinated to prevent certain infections. Your doctor will advise you what is needed for your condition. Read more about how can I care for myself with congenital heart disease in the next section.
• Medicines – some types of heart defects can be treated by medicines  or require medicines to stabilise the condition before surgery.
• Surgery and operations – surgery may sometimes be needed to fix certain types of heart defects.

Some types of heart defects don’t require treatment as the defect will heal itself when your child grows. Talk to your doctor and healthcare team to find out the best treatment option for you or your child.

For many people, congenital heart disease is something you have for the rest of your life. While you may not face ongoing heart problems, you are at increased risk of developing complications.

Even if you have surgery, you need follow-up care for the rest of your life. This may be as simple as an annual check-up with your GP, or may require more extensive testing with your cardiologist (a heart specialist doctor). The most important thing is that you understand the condition and the steps to take to keep your child (or yourself) healthy. 

Here are some things to keep in mind:

• Good dental hygiene is important as bacteria can spread from your mouth to your bloodstream and cause a heart infection (infective endocarditis).
• Get any dental problems such as a dental abscess or gum disease treated.  
• Tell your dentist about your heart condition before you get any dental work done. You may need to take a preventative course of antibiotics.
• Make sure your child’s vaccinations are up-to-date to prevent infections.
• You or your child may need to avoid strenuous exercise – your doctor will advise what is needed for your condition.
• Healthy eating, regular exercise (check with your doctor first), being a non-smoker, taking your medicines correctly and having a positive attitude can also help you manage your condition well.

You can’t prevent your child from getting a congenital heart disease completely, but there are things you can do when you are pregnant to reduce the risk.

These include:

• getting vaccinated against rubella with the MMR vaccine before you are pregnant
• getting vaccinated against the flu before or while you are pregnant
• not drinking alcohol when you are trying to get pregnant and while pregnant
• avoiding medicines that can cause development defects in your child – check with your doctor or pharmacist before taking any medicines while pregnant
• taking folic acid supplements as advised by your doctor or midwife while trying to get pregnant and during the first 12 weeks of your pregnancy
• controlling your diabetes if you already have diabetes before getting pregnant
• avoiding contact with people who have an infection.

Read more about pregnancy health and wellbeing.

HeartKids NZ(external link)(external link) provides information and support for parents, carers and families about congenital heart disease. Visit their website(external link)(external link) or call them on 0800 543 943.

Heart Foundation NZ(external link)(external link) provides information and support for people who are living with a heart condition. Visit their website(external link)(external link) or call them on 0800 863 375.