There are over 40 different types of childhood heart conditions.

Every week, 12 children are being diagnosed with a childhood heart condition and over 550 major heart surgeries are carried out on heart children every year.

Congenital Heart Disease (CHD)

CHDs are the most common serious birth abnormality in Aotearoa New Zealand.

Congenital heart disease (CHD) is a general term that covers all structural problems with the heart that are present from birth. Hearts can have incomplete or missing parts, leaky valves, holes between chambers or are simply put together the wrong way. Some CHDs are simple and don’t need treatment, while others need serious intervention.

How are congenital heart conditions diagnosed?

Some CHDs can be detected pre-birth by a Level II ultrasound or by a foetal echocardiogram. After birth, a congenital heart condition is often first detected when the doctor hears an abnormal heart sound or heart murmur when listening to the heart. Depending on the type of murmur, the doctor may order further testing such as an echocardiogram, cardiac catheterization, chest x-ray, electrocardiogram (ECG/EKG), magnetic resonance imaging (MRI) or other diagnostic testing.

What are common signs and symptoms?

The warning signs in babies and children include:

  • A heart murmur or abnormal heart sound
  • Cyanosis (a bluish tint to the skin, fingernails and/or lips)
  • Fast breathing, poor feeding
  • Poor weight gain
  • An inability to exercise and excessive sweating
What are the most common CHDs?

While there are over 40 different congenital heart conditions, there are a few that are the most common. These are:

Aortic Valve Disease (AVD)

Aortic Valve Disease is a condition where the valve between the heart’s lower left chamber (left ventricle) and the main artery connecting the heart and the body (aorta) doesn’t work properly.

There are two common types of AVD:

Aortic valve stenosis: This occurs when the flaps of the aortic valve stiffen or fuse together, narrowing the valve’s opening and blocking the flow of blood from the heart to the body.

Aortic valve regurgitation: This is when the aortic valve doesn’t close properly, allowing blood to flow back into the left ventricle.

As well as being a congenital defect that’s present at birth, AVD is sometimes the result of infections. It can also develop in older adults who develop high blood pressure or heart injuries like heart attacks.

Find out more about AVD here and here.

Atrial Septal Defect (ASD)

As a baby develops in the womb, its heart has openings in the wall dividing the organ’s upper chambers (atria). These usually close during pregnancy, or just after birth. But sometimes they don’t, and the remaining hole is called an Atrial Septal Defect.

Sometimes, these holes close without treatment. But when they don’t, the hole results in more blood flowing through to the lungs. This can cause damage to the lung’s blood vessels, which can cause problems in adulthood like high blood pressure, heart failure, abnormal heartbeat and greater risk of stroke.

Find out more about ASD here and here.

Atrio-Ventricular Septal Defect (ASVD)

With AVSD, holes between the right and left sides of the heart means that blood flows where it shouldn’t. Often, the valves which control the blood flow are defective.

This results in blood with low oxygen levels, and extra blood flowing to the lungs. The heart and lungs are forced to work harder, which can lead to congestive heart failure.

In most cases of AVSD, surgery is needed in the first six months of a child’s life.

Find out more about ASVD here, here and here.

Coarctation of the Aorta (CoA)

Also known as aortic narrowing, CoA means the heart has to pump extra hard to force blood through the narrow part of the aorta.

While the narrowing is usually found near the ductus arteriosus blood vessel, it can affect any part of the aorta.

CoA is usually identified at birth, although it depends on how much the aorta has narrowed as to how likely it is to be detected. Sometimes it’s not discovered until adulthood.

CoA symptoms range from mild to severe. Babies on the severe end will generally start showing symptoms shortly after birth: pale skin, sweating and breathing difficulties. After infancy, symptoms include high blood pressure, headaches, muscle weakness, leg cramps, nosebleeds and chest pain.

While treatment has a good success rate, CoA generally results in lifelong monitoring.

Find out more about CoA here and here.

Cyanotic Congenital Heart Disease (CCHD)

A few conditions fall under the CCHD umbrella, with each resulting in low blood oxygen levels causing breathing difficulties, and giving lips, toes, palms or fingers a bluish tinge known as cyanosis.

Genetics can play a part in CCHD. That could mean a family history of congenital heart disease, or an accompanying condition like Down Syndrome.

Sometimes, external factors during pregnancy can cause CCHD. These include drug use, toxic chemical exposure, infections or poorly controlled gestational diabetes.

Find out more about cyanotic diseases here.

Hypoplastic Left Heart Syndrome (HLHS)

In this severe congenital heart defect, the left side of the heart is under-developed or small, unable to effectively pump blood to the body.

Most babies with HLHS need urgent surgery to survive.

Find out more about HLHS here and here.

Mitral Valve Defects (MVD)

In this condition, a fault in the mitral valve causes blood to flow back into the heart’s left atrium and means the heart can’t pump enough blood out of its left ventricular chamber. This back flow is known as mitral valve regurgitation.

Mitral valve stenosis – when the mitral valve is narrowed, blocking blood flow to the left ventricle – is often caused by rheumatic fever, a complication of a strep infection. However, in some cases, mitral stenosis is congenital.

Mitral valve prolapse (MVP) is a common congenital heart defect. The valve is abnormally formed in such a way that the two valve flaps bend backwards into the left atrium as the heart beats.

Find out more about mitral valve defects here and here.

Patent Ductus Arteriosus (PDA)

In a growing fetus, the ductus arteriosus blood vessel connects the aorta and the pulmonary artery. The tube normally closes around the time of birth. However, when it doesn’t, it results in blood flow to the lungs, making the heart and lungs work harder.

However, if the tube is small and not impacting the way these organs work, intervention might not be necessary.

Find out more about PDA here.

Pulmonary Artresia (PA)

PA is a defect of the pulmonary valve, which controls the blood flow from the heart’s lower right chamber to the main pulmonary artery (the blood vessel between the heart and the lungs).

When this valve doesn’t form properly, blood is prevented flowing from the heart’s right ventricle to the lungs.

Babies born with PA will need medication to keep their ductus arteriosus open, helping with blood flow to the lungs until the valve can be repaired.

Find out more about PA here.

Pulmonary (Valve) Stenosis (PVS)

Pulmonary (valve) stenosis is a condition caused by blockage to blood flow from the right ventricle to the pulmonary artery. This blockage (obstruction) is caused by narrowing (stenosis) at one or more points from the right ventricle to the pulmonary artery.

Children with pulmonary valvar stenosis are usually symptom free and in normal health. A heart murmur is the most common sign found by a doctor that shows that a valve problem may be present.

A newborn with critical pulmonary stenosis is an emergency that needs immediate treatment.

Find out more about PVS here and here.

Pulmonary Valve Disease (PVD)

When the pulmonary valve (located between the right ventricle and the pulmonary artery) doesn’t work properly, it can affect the flow of blood from your heart to your lungs. The treatment for pulmonary valve disease depends on the type and severity of the condition.

Single Ventricle Pathology (SVP)

If a lower ventricle fails to develop, the heart is left with just one blood-pumping chamber. This means less oxygen-rich blood flowing around the body.

Some children with single ventricles will have other heart defects, too. And in most, the  cause is unknown. Surgery and medical intervention will be required to ensure the blood pumps around the body in the right way.

Find out more about single ventricle anomalies here and here.

Tetralogy of Fallot (ToF)

This condition is a combination of four defects of the heart and its blood vessels:

  • Ventricular septal defect: a hole in the wall between the heart’s two lower chambers (ventricles).
    Pulmonary stenosis: a narrowing of the pulmonary valve, and main pulmonary artery.
    Ventricular hypertrophy: when the heart’s right ventricle wall is thicker than normal.
    Overriding aorta: when the aortic valve is enlarged, and seems to open from both ventricles, unlike a normal heart, which opens from the left.

In ToF, abnormal blood flow from the heart to the lungs results in blood being diverted through the ventricular septal defect to the aorta. This can cause lower blood flow and lung circulation and causes the child to appear blue.

ToF is considered severe, and a baby born with the condition will likely need surgery or other interventions shortly after birth.

Find out more about ToF here and here.

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.’

Find out more about TGA here, here and here.

Ventricular Septal Defect (VSD)

The most common heart defect in children, VSD is formed during pregnancy, when the wall (septum) separating the heart’s lower chambers (ventricles) doesn’t form properly.

The resulting hole allows blood to pass between the left and right side of the heart. The blood is then pumped into the lungs instead of out to the body, forcing the heart and lungs to work harder.

Without repair, the defect can cause other complications like heart failure, high blood pressure in the lungs (pulmonary hypertension), irregular heart rhythms (called arrhythmia), or stroke.

Find out more about VSD here and here.

Where can you find out more?

There are several resources and websites in Aotearoa New Zealand and abroad that provide a range of information relating to CHD. We recommend the following:

Acquired Childhood Heart Disease

An acquired heart condition is an issue with a child’s heart that develops after birth. They can be caused by bacterial or viral infections or be the result of chronic diseases or medications that affects other parts of the body.

Who is affected by acquired heart conditions?

Both adults and children, although acquired heart conditions are much less common in children.

What are the main types of acquired heart conditions in children?

Thankfully, there aren’t as many acquired childhood heart conditions as there are congenital. Here are the main ones:

Rheumatic Fever and Rheumatic Heart Disease (RHD)

Rheumatic heart disease is caused when rheumatic fever – an inflammatory disease that affects the heart, brain, skin and joints – causes damage to the heart valves.

Rheumatic fever is a serious but preventable autoimmune disease that develops when streptococcal infections like strep throat or scarlet fever are left untreated. Children who have repeated strep throat infections are most at risk for developing rheumatic fever and rheumatic heart disease.

Rheumatic heart disease can begin quickly after a strep infection or years later; over time, heart valves can become scarred which leads to leaking or narrowing.

Rheumatic fever mainly affects Māori and Pacific children between 4 and 19 years old, especially if other family members have had the disease.

Many young people who develop rheumatic heart disease need lifelong antibiotic injections and blood-thinning medication.

Common symptoms of rheumatic fever:

  • Fever
  • Painful joints, especially knees, ankles, elbows and wrists
  • Fatigue
  • Heart murmur
  • Pain that moves between different joints
  • Jerky, uncontrollable body movements
  • Painless nodules under the skin and/or rash consisting of pink rings with a clear centre (both are rare symptoms)

Symptoms of heart valve damage due to rheumatic heart disease:

  • Shortness of breath
  • Chest pain or discomfort
  • Fatigue
  • Swelling of the stomach, hands or feet
  • Rapid or irregular heartbeat

Treatment of rheumatic heart disease

There is no cure for rheumatic heart disease; the damage to the heart valves is permanent. Surgery is often required to replace or repair the damaged valve or valves in patients with severe rheumatic heart disease. Medication may also be needed to treat symptoms of heart failure or heart rhythm abnormalities depending on the severity of the disease. Medications to thin the blood and reduce the risk of blood clots may also be needed.

Further reading:

Kawasaki Disease (KD)

Kawasaki disease is one of the most common causes of acquired heart conditions. It mostly affects children under five and is more common in boys.

It’s unknown what causes KD, although it’s believed it can be triggered by an infection. If symptoms are recognised at an early stage and treated, most children make a full recovery. However, without treatment, one in four children with KD will develop coronary artery dilation, putting them at risk of heart disease.

Sign and symptoms of Kawasaki disease:

  • Fever
  • Spotty rash on the chest, back, abdomen or groin
  • Red eyes or light sensitivity
  • Swollen or cracked lips
  • A red tongue
  • Swollen hands and feet
  • Redness of the palms and soles
  • Swollen lymph nodes in the neck

Treatment of Kawasaki disease

Treated in the hospital, the standard initial treatment is intravenous immunoglobulin (IVIG) and aspirin. Given early in the illness, IVIG can reduce the risk of coronary artery issues, and the aspirin reduces fever, pain and joint swelling and can reduce the risk of blood clots forming.

Further Reading:

Myocarditis, Endocarditis and Pericarditis

All types of heart inflammation, causes can include bacterial or viral infection, autoimmune diseases such as rheumatoid arthritis or lupus or cancer.

Myocarditis: The myocardium (heart muscle) becomes inflamed. Although it will often heal on its own a severe case can weaken a child’s heart and potentially lead to abnormal heart rhythms, blood clots or heart failure.

Endocarditis: An infection that invades the heart valves, most often caused by a bacterial infection. Although rare, it is more common in those with congenital heart or valve conditions.

Pericarditis: The pericardium (sac that surrounds the heart) becomes inflamed or irritated. Most cases will be mild and only require medication, but in rare cases too much fluid builds in the pericardium.

Depending on the area of the heart affected, signs and symptoms may include:

  • Fever or chills
  • Fainting
  • Fatigue, weakness or nausea
  • Rapid breathing or shortness of breath
  • Arrhythmia (irregular heartbeat)
  • New heart murmur or changes to an existing one
  • Chest pain
  • Heart Palpitations
  • Night Sweats
  • Pain or shortness of breath when lying down

Treatment: For many patients heart inflammation improves on its own without intervention. For others, treatment options can include surgery and/or medication.

Long QT Syndrome (LQTS)

Long QT syndrome (LQTS) is rare disorder where your heart takes longer than usual to recover after each beat. It affects one in 5,000 people. At its most basic level, long QT syndrome is an electrical problem. Long QT syndrome be inherited or acquired. In other words, it can have root causes in your genes and start at birth or come later in life due to some other cause.

Further reading:


An arrhythmia is an irregular heartbeat. It means your heart is out of its usual rhythm. It may feel like your heart skipped a beat, added a beat, or is “fluttering.” It might feel like it’s beating too fast (which doctors call tachycardia) or too slow (called bradycardia). Or you might not notice anything.

Arrhythmias are divided up by where they happen. If they start in the ventricles, or lower chambers of your heart, they’re called ventricular. When they begin in the atria, or upper chambers, they’re called supraventricular.

Doctors also group them by how they affect your resting heart rate. Bradycardia is a heart rate of fewer than 60 beats per minute. Tachycardia is more than 100 beats per minute.

Further Reading:

Where can you find out more?

There are several resources and websites that provide a range of information relating to acquired heart conditions. We recommend the following: