Congenital heart disease

What is congenital heart disease?

Congenital heart disease is a heart condition you are born with. The word congenital means “present at birth.” Congenital heart disease can range from very minor conditions which never cause problems, to more serious conditions that require treatment.

A congenital heart defect happens when the chambers, walls or valves of your heart – or the blood vessels near the heart – don’t develop normally before birth. There are many different types of defects listed below.

If congenital heart disease has affected you or your family, it is important to know that:

  • The outlook for children with congenital heart disease has improved thanks to medical advances in Canada and around the world. 
  • Many adults are able to avoid or manage complications,and improve their quality of life because of improvements in the management and care of congenital heart disease.
9 in 10

Today, 9 in 10 children with congenital heart disease survive to adulthood.

Types of congenital heart defects

There are many ways that a heart can be affected before birth and many different types of congenital heart defects. It might help you to learn the parts of a healthy heart and how they work together.

There are two main types of congenital heart defects.   

1. Holes in the heart (septal defects)

When a baby is born with an abnormal opening in the wall that separates the right and left chambers of the heart (the septum), blood can leak between the chambers instead of flowing normally to the rest of the body. This may cause the heart to become enlarged.

The most common holes in the heart are:

  • Atrial septal defect (ASD) Normally, oxygen-rich blood that's already been to the lungs flows from the left atrium to the left ventricle, out the aorta and to the body. An abnormal opening between the right and left atria (the upper chambers of the heart) allows some blood from the left atrium to leak back into the right atrium. Your heart has to work extra hard to move the extra blood out to the lungs. The seriousness of the problem depends on the size of the opening.

    Patent foramen ovale (PFO) is one type of atrial septal defect. The hole between the left and right atria usually closes within the first few years of life. Even if it doesn’t close, the hole may not cause any complications unless you have a second heart defect. PFOs are very common and many people will never know they have one.
  • Ventricular septal defect (VSD) If there is a hole between your right and left ventricles, oxygen-rich blood returning from your lungs leaks from the left ventricle into the right ventricle instead of being pumped into the aorta and out to the rest of your body. Depending on the size of the opening, you may need surgery to close the hole.

2. Obstruction of blood flow

Stenosis is a narrowing or obstruction in heart valves, arteries or veins that affects the flow of blood. Atresia is when a passageway in the body is abnormally shut or has not formed properly. Different types of stenosis and atresia can partly or completely block blood flow in the heart.

  • Pulmonary valve stenosis If your pulmonary valve narrows, the flow of oxygen-poor blood from the right ventricle through the pulmonary arteries to your lungs is restricted. This interferes with the blood’s ability to pick up oxygen and deliver it to the rest of your body. The right ventricle has to work harder to pump blood through the narrowed pulmonary valve and the pressure in the heart is often increased.
  • Pulmonary atresia The pulmonary valve lets blood flow from the right ventricle to the lungs via the pulmonary artery. In pulmonary atresia, the pulmonary valve does not form properly and it remains closed at birth. Blood is not able to flow properly to the lungs to get oxygenated. If left untreated, this condition is fatal. Visit About Kid’s Health to learn more.
  • Tricuspid atresia The tricuspid valve controls blood flow between the right atrium and the right ventricle. In tricuspid atresia, the valve does not form properly and there is no opening between these two chambers. Blood is not able to flow from the right atrium into the right ventricle and then onto the lungs, to get oxygenated. If left untreated, this condition is fatal. Visit About Kid’s Health to learn more.
  • Aortic stenosis When the aortic valve narrows, blood flow is restricted from the heart through the main artery to your body (aorta) and onwards to the rest of the body. As a result, the left ventricle has to contract harder to push blood across the aortic valve. This eventually weakens the heart muscle and makes your heart less efficient. Surgery may be necessary. Aortic stenosis can be treated, but life-long follow-up will be needed.
  • Coarctation of the aorta This is the narrowing of the largest artery in the body. When the aorta is pinched or constricted, the flow of blood to the lower part of the body is reduced and blood pressure above the constriction is increased. The heart is forced to pump harder in order to deliver enough blood to the rest of your body. Coarctation of the aorta can range from mild to severe. It usually occurs with other heart defects. The condition can be treated, but life-long follow-up will be needed.
  • Patent ductus arteriosus The ductus arteriosus is a passageway for blood between the aorta and pulmonary artery that normally closes a few days after birth. If it fails to close properly, too much blood flows to the lungs. The condition is common in premature babies, but rare in full-term babies. How serious it is depends on how large the opening is and how premature the baby is. In some circumstances an open ductus is necessary for survival – where blood flow is blocked, or if the blood vessels supplying the lungs and body are switched (transposition of the great arteries).

    Medication in the first few weeks of life can either close (or keep open) the ductus arteriosus. As your baby gets older and if the medication isn’t working, the ductus can be closed off using a cardiac catheterization procedure. This will restore normal circulation.
  • Blue babies (cyanotic defects) When blood that is pumped from the lungs and heart to the body contains less-than-normal amounts of oxygen, it causes a blue discoloration of the skin, lips, gums, nail beds, and the areas around the eyes and mouth (cyanosis). There are several different conditions that can lead to a blue baby.
    • Tetralogy of fallot is a combination of four defects that make the level of oxygen in the blood too low:
      • A large hole in the wall between the two ventricles allows some oxygen-rich blood to be pumped to the right side of the heart instead of to the rest of the body through the aorta. (See ventricular septal defect above.)
      • A narrowing of the pulmonary valve can block the flow of blood from the right side of the heart to the lungs. (See pulmonary valve stenosis above.)
      • A more-muscular-than-normal right ventricle can cause the heart muscle to become stiff over time, eventually making the heart weak (right ventricular hypertrophy).
      • An aorta that lies directly over the right ventricle allows a mixture of oxygen-rich and oxygen-poor blood to flow into the aorta (overriding aorta).
    • Transposition of the great arteries In this condition, your baby’s pulmonary artery and the aorta are reversed. Their aorta is connected to the right ventricle, so most of the blood returning to the heart from the body is pumped back out to their body without first getting oxygen from the lungs. The pulmonary artery is connected to the left ventricle, so that most of the oxygen-rich blood returning from their lungs goes back to the lungs again. The condition is often detected during the first week of life and can be corrected with surgery during your baby’s first month.

      Other defects between the right and left sides of the heart often co-exist with transposition of the great arteries. An atrial septal defect, ventricular septal defect or ductus arteriosus can actually help oxygenated blood circulate to the body.
    • Ebstein's anomaly The tricuspid valve controls blood flow between the right atrium and the right ventricle. Ebstein’s anomaly is a rare condition in which the tricuspid valve is located lower than normal and has abnormal flaps (leaflets). This can cause blood to leak backwards through the valve and prevent the heart from working efficiently. This causes the ventricle to be too small and the atrium to be too large. Many children with Ebstein’s anomaly have mild cases that don’t cause symptoms. If your child’s tricuspid valve is leaking badly, heart valve surgery may be necessary.
  • Hypoplastic left heart syndrome Children born with this syndrome have an underdeveloped left side of their heart.
    • The left ventricle is underdeveloped and too small.
    • The mitral valve is not formed or too small.
    • The aortic valve is not formed or too small.
    • A part of the aorta (the ascending aorta) is underdeveloped or too small.

    Children with this condition often have an atrial septal defect as well (see above).

Often, there’s no known cause for congenital heart disease.

Known causes include:

  • exposure of the fetus to maternal illnesses such as diabetes, German measles (rubella), fever illnesses and a problem metabolising an amino acid during pregnancy (phenylketonuria)
  • smoking, alcohol or recreational drug use during pregnancy
  • some therapeutic drugs (thalidomide)
  • environmental factors such as air pollution, pesticides and extreme heat waves
  • certain inherited genetic defects and chromosomal abnormalities

Diets rich in folic acid, vitamin B2, riboflavin and nicotinamide have been shown to help protect unborn children from congenital heart disease.


The symptoms of congenital heart defects include:

  • heart murmur
  • rapid, fluttering, pounding heartbeats (heart palpitations)
  • abnormal heart rhythms (arrhythmia)
  • bluish tint to the skin, lips and fingernails (blue baby, cyanosis)
  • cool, clammy skin
  • fast breathing
  • shortness of breath
  • fainting
  • poor feeding – especially in infants because they tire easily while nursing
  • poor weight gain in infants
  • fatigue during exercise or activity in older children
  • irritability and/or prolonged crying
  • abnormal rounding of the nail-bed (clubbing)
  • stroke

A congenital heart defect may be discovered through an ultrasound during pregnancy, from a physical examination after birth or because of a baby’s symptoms. Some defects aren’t discovered until adulthood, when your body puts greater demands on your heart.

If your healthcare team suspects that you or your child may have a heart defect, you will be referred to a cardiologist or a pediatric cardiologist. Your doctor will do a physical exam and look into your:

  • signs and symptoms
  • medical history
  • family history
  • test results.

Tests may include:

  • pulse oximetry – measures the oxygen in a baby’s blood through a sensor attached to their hand or foot.
  • cardiac catheterization
  • chest X-ray
  • echocardiogram – can be done before a child is born.
  • ECG or EKG (electrocardiogram)
  • heart MRI (magnetic resonance imaging)
  • genetic testing – may be done if the healthcare team suspects a heart defect is related to a genetic condition.

Treatment for congenital heart disease may include medications, surgery and other procedures, and lifestyle changes. You and your doctor will discuss the treatment options for your specific condition and decide what is best for you and your circumstances.


Medications may be used to treat your symptoms and improve your condition. They can reduce the stress on your heart by controlling blood pressure, heart rate, irregular heart rhythm (arrhythmia) or the amount of fluid in your body.

Medications you are prescribed may include:

  • ACE inhibitors
  • beta-blockers
  • diuretics
  • digoxin
  • inotropes – used to strengthen your heart's ability to pump
  • prostaglandin E1 (PGE1) – a substance that keeps the ductus arteriosus open in children with patent ductus arteriosus (see above). The open ductus arteriosus improves blood flow and oxygen levels until the defect is surgically corrected.
  • antiarrythmics 
  • antibiotics – may be recommended before and after dental work or other medical procedures to prevent infection of the heart (endocarditis). Speak to your dentist or doctor about antibiotics before dental work. 

Surgery and other procedures

Some congenital heart defects may require surgery or other procedures to:

Catheter-based procedures (non-surgical)

  • Cardiac catheterization is often used to repair simple holes in the heart or open narrowed areas without surgery. A thin tube (catheter) is inserted into a blood vessel in the groin or arm and guided to the heart so that a surgeon can insert a plug inside the hole to repair it.
  • Percutaneous valve repair or replacement is used to repair defective cardiac valves that can be either too narrow or leaky.
  • Transcatheter aortic valve implantation (TAVI) (also called transcatheter aortic valve replacement) is a relatively new valve replacement procedure that places an artificial aortic valve on top of the damaged aortic valve rather than replace it. TAVI is usually considered for people who are at high risk for complications from open-heart surgery. TAVI is not available in all medical centres in Canada.

Surgical procedures

Open heart surgery through the chest may be necessary to fix problems that can’t be solved with less invasive procedures. Surgery may be used to:

You and your doctor will discuss the surgical options that are best for your condition.


You can lower your risk of developing other heart diseases and stroke by knowing and controlling your blood pressure, diabetes and blood cholesterol. It’s also important to lead a healthy lifestyle.

Talk to your doctor about the lifestyle changes that will benefit you the most.

Living with congenital heart disease

Many people who have congenital heart disease lead full lives. Here are some things to be aware of as you learn to live with your heart condition.

  • Once teenagers with congenital heart disease have transitioned to adult care at age 18, they should be seen by a cardiologist specially trained in treating adults with congenital heart disease. Visit the Canadian Congenital Heart Alliance (CCHA) to find an adult congenital heart disease centre in Canada. You can help your child learn to talk to their doctors and other healthcare providers about their health, and to understand the importance of health insurance and what medical care it covers.
  • To protect your health, learn the signs and symptoms to watch for. 
  • Ask your doctor if you would benefit from cardiac rehabilitation. Cardiac rehab is a personalised program of exercise, education and counselling. Rehab will help you regain your strength and reduce your risk of having other heart problems in the future. Talk to your doctor about a program in your area or contact your public health department or hospital. The Canadian Association of Cardiac Rehabilitation also has a cardiac rehabilitation program directory to help you find a program in your community.
  • People with congenital heart disease may be at risk of developing infective endocarditis. To reduce the risk of infection of the heart, talk to your dentist or doctor about the need for taking antibiotics before and after dental cleanings or surgery.
  • Vaccines to prevent flu and pneumonia are another proactive way to stay healthy. Many people with chronic heart problems are less able to fight infections. You might be more susceptible to respiratory tract infections that can lead to serious complications and even death. Talk to your doctor about the flu vaccine.
  • Women with CHD face unique birth control and pregnancy challenges. 
  • It’s normal to feel worried or afraid after a diagnosis of congenital heart disease. Talking about challenges and feelings could be an important part of the journey to recovery. Find someone your family can turn to for emotional support like another family member, friend, doctor, mental health worker or support group. Join our online community of survivors and sign up for our recovery newsletter. You will get the latest research news, information, tips and strategies to help you manage your recovery. Find peer support resources here.
Related information

To find useful services to help you on your journey with heart disease, see our services and resources listing.

To learn more about CHD, check our other webpages. 

The Hospital for Sick Kids website About Kid’s Health has resources to help you support your child. Use their search function to find more information on each of the conditions listed on this webpage. Check out:

The Canadian Congenital Heart Alliance (CCHA) aims to improve the quality of life and health outcomes for adults with congenital heart defects by raising awareness, providing peer support, mentoring and advancing research.

You can also visit The Canadian SADS Foundation to learn more about cardiac disorders that can cause sudden death in young people.

 A British Heart Foundation video explains CHD, and highlights the most common conditions.


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