CoHD Condition Types

Find trusted information on the spectrum of childhood-onset heart disease (CoHD) condition types, including congenital heart diseases and acquired heart diseases.

Congenital Heart Diseases (CHD)

Each year, between 2,400 and 3,000 Australian babies are born with a form of congenital heart disease. It is the most common congenital disorder in newborns affecting up to 1 in 100 births.

CHD incorporates a group of abnormalities of the heart and is a general name for any type of malformation of the heart, heart valves or major blood vessels which are present at birth. Defects can range from simple to complex and can occur alone or in groups, depending on how the heart has developed.

Aortic Valve Disease

Aortic valve disease is a condition in which the valve between the main pumping chamber of your heart (left ventricle) and the main artery to your body (aorta) doesn't work properly.


There are two commonly known types of AVD:

  • Aortic valve stenosis: Occurs when the flaps (cusps) of the aortic valve may become stiff or fuse together. This causes narrowing of the aortic valve opening. The narrowed valve cannot open fully, which can block blood flow from the heart into the body (aorta) and the rest of the body.
  • Aortic valve regurgitation: Occurs when the aortic valve doesn't close properly, causing blood to flow backward into the left ventricle.

Aortic valve disease may be a heart defect condition present at birth (congenital).


AVD may be a heart condition that is present at birth (congenital).

Other causes that may result in AVD include:

  • Infections (from endocarditis or rheumatic fever)
  • Age-related changes to the heart (calcium deposits may cause the valves to become stiff and thickened)
  • High blood pressure or injury to the heart (heart attack and heart failure)

Learn more about Aortic Valve Stenosis

Atrial Septal Defect (ASD)

Atrial septal defect (ASD) occurs when there is a hole in the wall (septum) that divides the upper chambers (atria) of the heart.

As a baby’s heart develops during pregnancy, there are normally several openings in the wall dividing the upper chambers of the heart (atria). These usually close during pregnancy or shortly after birth.

In some children, the hole (ASD) may close on its own without treatment.

The hole increases the amount of blood that flows through the lungs. Over time, it may cause damage to the blood vessels in the lungs.

Damage to the blood vessels in the lungs may cause problems in adulthood, such as high blood pressure in the lungs and heart failure. Other problems may include abnormal heartbeat, and increased risk of stroke.

Learn more about Atrial Septal Defects

Atrio-ventricular Septal Defect (AVSD)

Atrio-ventricular septal defect (AVSD) is a defect in which there are holes between the chambers of the right and left sides of the heart, and the valves that control the flow of blood between these chambers may not be formed correctly.

In AVSD, blood flows where it normally should not go. The blood may also have a lower than normal amount of oxygen, and extra blood can flow to the lungs.

This extra blood being pumped into the lungs forces the heart and lungs to work hard and may lead to congestive heart failure.

Early surgical repair is needed in most cases (in the first 4 - 6 months).

This video explains AVSD:

Learn more about Atrio-ventricular Septal Defect

Coarctation of the Aorta

Coarctation of the aorta is also called aortic narrowing. If your aorta is narrow, it means your heart must pump harder to force blood through the narrow part.

Although this condition can affect any part of the aorta, the defect is most often located near a blood vessel called the ductus arteriosus. Symptoms can range from mild to severe.

Treatment is usually successful, but this condition still requires careful lifelong follow-up.

This video explains Coarctation of the Aorta:

Coarctation of the aorta often occurs along with other heart defects.


Coarctation of the aorta commonly presents at birth. Sometimes it might not be detected until adulthood, depending on how much the aorta is narrowed.

Babies with severe coarctation of the aorta may begin having symptoms shortly after birth. The signs include pale skin, irritability, heavy sweating, difficulty breathing and feeding.

Adults with coarctation of the aorta may also have signs or symptoms of other heart defects, which often occur with the condition. Signs or symptoms of coarctation of the aorta after infancy commonly include high blood pressure, headaches, muscle weakness, leg cramps or cold feet, nosebleeds, and chest pain.

Learn more about Coarctation Of The Aorta.

Cyanotic Congenital Disease (CCHD)

Cyanotic congenital heart disease (CCHD) refers to a group of many different heart defects that result in a low blood oxygen level.

Cyanosis refers to a bluish colour of the skin and mucous membranes. This often occurs in the lips, toes or fingers.


  • Blue lips, toes, or fingertips and palms.

Additionally, some children experience spells during which their oxygen levels are very low. As a result, they get anxious, which results in blue skin, and they may hyperventilate.


In many cases, genetics will play a role in a CCHD diagnosis.

  • Family history: An infant is more at risk for CCHD when there’s a family history of congenital heart diseases.
  • Genetic syndromes: Certain syndromes, such as down syndrome, can be accompanied by defects that cause CCHD.

In some instances, external factors can cause CCHD.

  • Toxic chemicals or drugs during pregnancy: If a pregnant woman is exposed to toxic chemicals or certain drugs, it can negatively affect her infant's heart development.
  • Infections during pregnancy: This can play a role in an infant developing CCHD.
  • Gestational diabetes: Poorly controlled gestational diabetes can lead to a higher risk of an infant developing CCHD.

Hypoplastic Left Heart Syndrome (HLHS)

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect in which the left side of the heart is underdeveloped or too small.

When this condition occurs, the left side of the heart cannot pump oxygen-rich blood to the body properly.

HLHS is amongst the most severe forms of heart defect. Most babies are very ill in the early days of life and need urgent surgery to survive.

This video explains HLHS:

Learn more about Hypoplastic Left Heart Syndrome (HLHS).

Hypoplastic Right Heart Syndrome (HRHS)

Hypoplastic right heart syndrome (HRHS) is a range of congenital defects in which the right-sided structures of the heart are underdeveloped or not formed.

When these structures (triscupid valve, right ventricle and/or pulmonary valve) are too small or do not function properly, the right side of the heart cannot send enough blood to the lungs.

Untreated HRHS causes a baby to have abnormally low oxygen levels.

Mitral Valve Disease

Mitral valve disease occurs when the mitral valve doesn’t work properly, allowing blood to flow backward into the left atrium.

As a result, your heart does not pump enough blood out of the left ventricular chamber.

Mitral valve disease has many causes. Some forms of mitral valve disease can be present at birth (congenital).

Mitral valve regurgitation can be caused by problems with the mitral valve, also called primary mitral valve regurgitation. Mitral valve regurgitation is often caused by mitral valve prolapse, in which the mitral valve flaps (leaflets) bulge back into the left atrium. Diseases of the left ventricle can lead to secondary mitral valve regurgitation.

Mitral valve stenosis is often caused by rheumatic fever, which is a complication of a strep infection that can affect the heart.

Persistent Ductus Arteriosus (PDA)

Persistent ductus arteriosus (PDA) is the name of the tube that carries blood between the aorta and the pulmonary artery in the foetus.

This tube normally closes at or shortly after birth. Sometimes, however, the mechanism of closure does not work.

When the connection remains open, it causes blood to enter your lungs. This means your heart and lungs have to work harder.

If the PDA is small, it doesn't have to be closed because it doesn't make the heart and lungs work harder.

Aortic valve disease may be a heart defect condition present at birth (congenital).

Learn more about Persistent Ductus Arteriosus (PDA)

Pulmonary Atresia

Pulmonary atresia is a defect of the pulmonary valve.

Your pulmonary valve usually controls the blood flow from the lower right chamber of the heart to the main pulmonary artery (the blood vessel that carries blood from the heart to the lungs).

Pulmonary atresia is when this valve doesn’t form, and no blood can go from the right ventricle of the heart out to the lungs.

Most babies with pulmonary atresia will need medication to keep the ductus arteriosus open after birth.

Keeping this blood vessel open will help with blood flow to the lungs until the pulmonary valve can be repaired.

Learn more about Pulmonary Atresia

Pulmonary Stenosis

Pulmonary stenosis (also called pulmonic stenosis) is when the pulmonary valve (the valve between the right ventricle and the pulmonary artery) is too small, narrow, or stiff.

Symptoms of pulmonary stenosis depend on how small the narrowing of the pulmonary valve is.

If symptoms are mild, pulmonary stenosis may never need any treatment.

More severe pulmonary stenosis will need a procedure to fix the pulmonary valve so blood can flow properly through the body.


In children, pulmonary stenosis happens when a baby's heart doesn't develop the way it should during pregnancy.

Doctors don't know why this happens. It isn't caused by anything a mother did or didn't do during her pregnancy, so could not have been prevented.

Learn more about Pulmonary Stenosis

Pulmonary Valve Disease

Pulmonary valve disease is a condition in which the pulmonary valve doesn't work properly. This condition can interrupt blood flow from the heart to your lungs.

The pulmonary valve is located between the heart's lower right heart chamber (right ventricle) and the artery that delivers blood to the lungs (pulmonary artery).

Treatment depends on the type and severity of the condition.

Single Ventricle Pathology

Single ventricle pathology occurs when one lower chamber (ventricle) does not develop.

This results in the heart having only one pumping chamber. The result is that the amount of oxygen-rich blood getting to the body is decreased.

In most children, the cause isn't known. Some children can have other heart defects at the same time too.

Learn more about Single Ventricle Pathology

Tetralogy of Fallot (ToF)

Tetralogy of Fallot (ToF) is made up of a combination of four defects that commonly occur together.

ToF is made up of the following four defects of the heart and its blood vessels:

  • Ventricular septal defect: A hole in the wall between the two lower chambers (ventricles) of the heart.
  • Pulmonary stenosis: A narrowing of the pulmonary valve and main pulmonary artery.
  • Ventricular hypertrophy: The muscular wall of the lower right chamber of the heart (right ventricle) is thicker than normal.
  • Overriding aorta: Occurs when the aortic valve, which opens to the aorta, is enlarged and seems to open from both ventricles, rather than from the left ventricle only, as in a normal heart. In this defect, the aortic valve sits directly on top of the ventricular septal defect.

This video explains Tetralogy of Fallot:

What happens?

The abnormal flow of blood from the heart into the lungs leads to blood being diverted through the ventricular septal defect (VSD) to the aorta. Blood flow and lung circulation is reduced causing the child to appear blue.

Because a baby with ToF may need surgery or other procedures soon after birth, this birth defect is considered a critical congenital heart defect.

Learn more about Tetralogy of Fallot

Transposition of the Great Arteries (TGA)

Transposition of the great arteries (TGA) is a birth defect in which the two main arteries carrying blood out of the heart (the main pulmonary artery and the aorta) are switched in position, or 'transposed.'

In babies with TGA, oxygen-poor blood from the body enters the right side of the heart. But, instead of going to the lungs, the blood is pumped directly back out to the rest of the body through the aorta.

Oxygen-rich blood from the lungs entering the heart is pumped straight back to the lungs through the main pulmonary artery.

This video explains TGA:

TGA is considered a critical congenital heart defect.

This is because a baby with this defect may need surgery or other procedures soon after birth.

Other defects

Often, babies with TGA have other heart defects.

This can include a hole between the lower chambers of the heart (a ventricular septal defect) or the upper chambers of the heart (an atrial septal defect) that allow blood to mix so that some oxygen-rich blood can be pumped to the rest of the body.

The patent ductus arteriosus also allows some oxygen-rich blood to be pumped to the rest of the body.

Learn more about Transposition of the Great Arteries

Ventricular Septal Defect (VSD)

Ventricular septal defect (VSD) means there is a hole in the heart.

The hole occurs in the wall (septum) that separates the heart's lower chambers (ventricles) and allows blood to pass from the left to the right side of the heart. The oxygen-rich blood then gets pumped back to the lungs instead of out to the body.

A VSD happens during pregnancy if the wall that forms between the two ventricles does not fully develop, leaving a hole.

In a baby with a VSD, blood often flows from the left ventricle through the VSD to the right ventricle and into the lungs. This extra blood being pumped into the lungs forces the heart and lungs to work harder.

VSD is the most common type of congenital heart defect.

Over time, if not repaired, this defect can increase the risk for other complications, including heart failure, high blood pressure in the lungs (called pulmonary hypertension), irregular heart rhythms (called arrhythmia), or stroke.

Learn more about Ventricular Septal Defects.

Acquired Childhood Heart Disease

While people often think of acquired heart disease in adults, it is relatively common in children too. Some of the more common heart conditions acquired during childhood include Kawasaki Disease and Rheumatic Heart Disease.

Kawasaki Disease (KD)

Kawasaki disease (KD) is a relatively uncommon illness that mostly affects children under 5 years of age.

The most serious complication of KD is damage to the coronary arteries, which supply blood to the heart.

If untreated, up to 25% of children with KD develop coronary artery dilation which can damage the coronary arteries and put them at risk of heart disease.

If the symptoms and signs of KD are recognised early and treated with intravenous immunoglobulin, most children make a full recovery and coronary artery complications are prevented or minimised.

KD primarily affects young children. Approximately 75% of patients are under 5 years of age. Older children and more rarely teenagers can also get KD. It is more common in boys than girls.

Kawasaki Disease (KD) is the leading cause of acquired heart disease in children.


Early symptoms of Kawasaki Disease include:

  • Fever that can last for several days
  • Rash, can be over whole body and may be worse in the groin area
  • Red eyes – without discharge
  • Bright red, swollen, or cracked lips
  • Red tongue (strawberry like)
  • Swollen hands and feet
  • Redness of the palms and soles
  • Swollen lymph node in the neck

Children with KD are often very irritable.


There is no specific test for Kawasaki Disease. Doctors make a clinical diagnosis based on symptoms, physical findings and laboratory tests.


The cause of Kawasaki Disease is unknown. It is thought that an infection may trigger the condition, but KD is not contagious.

Learn more about Kawasaki Disease

Rheumatic Heart Disease (RHD)

Rheumatic heart disease is a serious disease of the heart involving damage to one or more of the four small heart valves. The valve damage can remain after acute rheumatic fever.

During rheumatic fever the heart valve tissue, and sometimes other parts of the heart (the heart lining or muscle) can become swollen and/or inflammed, and this is called carditis.

Following carditis, the heart valves can remain damaged then become scarred, and the result is an interruption to normal blood flow through the damaged valves.

When the heart is damaged in this way, the heart valve is not able to function adequately, and this is called rheumatic heart disease.

A person who has been diagnosed with RHD is required to have a lifelong treatment schedule of antibiotic injections and daily blood-thinning medications. HeartKids works side by side with Aboriginal and Torres Strait Islander Community-Controlled organisations and communities to develop culturally safe and responsive resources aimed at education and prevention of RHD.

RHD has a high impact on the social and emotional wellbeing of Aboriginal and Torres Strait Islander people, especially youth, who are at higher risk due to inadequate housing and inequitable health care.

Many of these young people face a lifelong treatment regime of monthly antibiotic injections and daily blood-thinning medication.

Between 30-40 young people with RHD per year travel from the Northern Territory to The Royal Children's Hospital in Melbourne for surgery.

Learn more about Rheumatic Heart Disease (RHD)

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