Anomalous pulmonary venous connection (APVC), where all veins from the lungs are connected to the right (instead of the left) collecting chamber (atrium) of the heart. This is usually diagnosed by echocardiogram and occasionally MRI. The type of abnormal connection (partial or total), determines whether surgery needs to be carried out urgently or not. An interventional approach is only carried out as a rescue treatment.

Aortic stenosis is where the valve connecting the left pumping chamber of the heart and the main artery that goes to the body is too narrow. This is typically diagnosed by echocardiography and treated with interventional cardiac catheterisation. Depending on the severity and the presence of other heart conditions, surgery might be necessary.

Atrial septal defect (ASD) is a connection (hole) between both collecting chambers (atria) of the heart.Diagnosis is usually by transthoracic, and occasionally, transoesophageal echocardiography. ASDs are commonly treated using cardiac catheterisation, but depending on the size and location of the defect, surgery may be necessary.

Coarctation (CoA) of the aorta is when the main body artery narrows, which means the blood supply to the lower half of the body is impaired. Diagnosis and treatment for babies is based on clinical findings (such as weak pulses in the legs) and echocardiography. Typically treatment is surgery, but occasionally cardiac catheterisation may be the treatment of choice. In older children, diagnosis is based on clinical findings (such as weak pulses in the legs and high blood pressure), echocardiography and MRI. Treatment depends on the type of lesion. Surgery may be recommended, but in teenagers and adults, interventional cardiac catheterisation is usually the preferred treatment

Complete atrio-ventricular septal defect (AVSD) is where instead of two valves connecting the two collecting chambers (atria) with the two pumping chambers (ventricles), there is only one common valve connecting all four chambers of the heart. Diagnosis is usually established by echocardiography and ECG (electrocardiogram). This heart condition is treated surgically. The timing of surgery is dependant on the size of the defect (hole) and how well the cardiac valves are working.

Partial atrio-ventricular septal defect (AVSD) is similar to complete AVSD outlined above. From the hemodynamics (bloodflow), this defect is very much the same as an ASD. However, as with the complete AVSD, the standard approach is surgery.

Hypoplastic left heart syndrome (HLHS) is when the left pumping chamber is underdeveloped. Treatment usually involves 3 operations:

• Carried out in the neonatal period
  
• In the first year of life
• Between the ages of 2 and 5

Recently, some patients have been able to have a combined surgical and interventional approach, avoiding cardiopulmonary bypass (hybrid operation).

Persistent ductus arteriosus (PDA) is an arterial duct between the main blood vessels of the heart is present during pregnancy. This should close during birth. Specialised devices now enable this to be closed in most patients. Pre-term babies still need surgery.

Pulmonary atresia with an intact ventricular septum is when the valve connecting the right pumping chamber of the heart (right ventricle) and the main artery to the lungs (pulmonary artery) does not open. The right ventricle can be underdeveloped. Depending on the size of the right ventricle, it may be possible to open the blockage with a balloon and insert a stent at the arterial duct. If the right ventricle grows well enough, surgery may not be necessary.

Pulmonary atresia with ventricular septal defect is the valve connecting the right pumping chamber of the heart (right ventricle) and the main artery to the lungs (pulmonary artery) does not open. Treatment depends on the size of the ventricles and the vessels connected to the heart. In most cases this involves surgery.

Pulmonary stenosis (PS) is when the valve connecting the right pumping chamber of the heart (right ventricle) and the main artery to the lungs (pulmonary artery) is narrow. In most cases, a heart murmur leads to further investigation. Diagnosis is by echocardiography. Usually, treatment involves heart catheterisation to open the narrow valve with a balloon.

Tetralogy of Fallot (ToF) is when the septum between both pumping chambers (ventricles) is not developed, leading to a narrowing of the outflow part of the right pumping chamber (ventricle), a ventricular septal defect with overriding of the aortic valve. Depending on the size of the child, surgery involves one or two steps. In some cases an artificial vessel (called a BT-shunt), is needed first to provide enough bloodflow into the lungs to allow the arteries to grow. Later, corrective surgery is carried out. In most cases the shunt is not necessary.

Transposition of the great arteries is when the main body artery (aorta) and the main lung artery (pulmonary artery) are both connected to the wrong pumping chamber (ventricle). Diagnosis is by echocardiography and treatment is usually within the first few days of life. Occasionally an MRI is needed to investigate the heart in even more detail. Treatment depends on the exact defect.

Congenitally corrected transposition of the great arteries is when the main body artery (aorta) and the main lung artery (pulmonary artery) are both connected to the wrong pumping chamber (ventricle). The collecting chambers are wrongly connected as well. Depending on the presence of additional congenital heart disease, treatment is timed.

Tricuspid atresia is when the valve connecting the right collecting chamber (atrium) and the right pumping chamber (ventricle) does not open. Treatment consists of staged surgery.

Ebstein's Anomaly is when the valve connecting the collecting chamber (atrium) and the right pumping chamber (ventricle) (the tricuspid valve) is displaced towards the tip of the heart. Depending on the degree of valvar displacement, surgery may be necessary. The frequent rhythm disturbances need to be followed.

Truncus arteriosus (single arterial trunk) is where instead of the main body artery (aorta) and the main lung artery (pulmonary artery) there is only one vessel arising from both ventricles. Treatment is usually surgery.

Ventricular septal defect (VSD) large is a large hole between both pumping chambers (ventricles). The large defects have to be closed surgically. Ventricular septal defect (VSD) small is a hole between both pumping chambers (ventricles). Depending on the location of the defect, cardiac catheterisation may be possible, avoiding open heart surgery.