Univentricular Heart occurs in a number of congenital heart conditions (a problem that a baby is born with). Below is a description of the heart condition and possible treatments offered.
In each of these conditions there is a large pumping chamber (ventricle) which both collecting chambers (atria) empty their blood into. There may be a valve at the end of each collecting chamber or just one between the two.
One of the ventricles will be smaller than the other and there will be a large hole (ventricular septal defect) between them. The two major blood vessels leaving the heart, the pulmonary artery to the lungs and the aorta to the body, may leave from either the left or right sides of the ventricle and they may be swapped around (transposed).
Treatment for this condition depends on the exact position of all the blood vessels. Your cardiac team will explain the treatment path for your child.
- Surgical treatments for right-sided single ventricle conditions
- Cavo-Pulmonary Connection (Stage Two) for all single ventricle conditions
- The Fontan Procedure (Stage Three) for all single ventricle conditions or completion of the Cavo-Pulmonary Connection
Surgical treatments for right-sided single ventricle conditions
It is often difficult to predict which early procedure will be most helpful in supporting a newborn baby with a complex right-sided single ventricle condition. Some children are born with too much blood flowing to their lungs, others with not enough. In some conditions it is not until after birth that the doctors are able to decide exactly which of the following procedures will be needed by each child.
Many single ventricle conditions cause a restriction of the blood supply to the lungs. As it is essential that blood flows to the lungs to collect oxygen for the body, connections must be created to re-route blood around any blockages within the heart. Surgeons will insert tubes made of either donated heart tissue or Gore-Tex (a specialised plastic) to form connections from the body circulation to the lung circulation. This treatment is often used within the first few weeks of life, as it is a simple solution to the circulation problem. Further more complex surgery will be done as the child grows.
Some children are born with a circulation that causes too much blood flow to the lungs. If the lungs are left with too high a flow, this can damage the lung blood vessels over time. To prevent this damage a band is placed around the base of the lung artery (pulmonary artery). This is usually removed at a later stage of surgery.
Septostomy or Septectomy
Many of the children are born with valves that are malformed so that they block the flow of blood around the heart. It is important to divert blood around the blockages by creating extra channels within the heart. Doctors may choose to create a hole between the two collecting chambers (atria) of the heart either during a cardiac catheterisation or during surgery.
Septectomy is the surgical procedure.
Septostomy is a cardiac catheterisation procedure. (See Cardiac Tests ).
Cavo-Pulmonary Connection (Stage Two) for all single ventricle conditions
Bi-directional Cavo-Pulmonary Shunt (Glenn Shunt) or The Hemi-Fontan Operation
As the children grow, they will require a more permanent supply of blood to their lungs than earlier surgical procedures can provide. A Cavo-Pulmonary Connection is normally performed between three and twelve months of age.
The aim of this operation is to redirect the flow of blue blood (deoxygenated blood) to the lungs by attaching the upper body vein (superior vena cava) directly on to the lung artery (pulmonary artery). The Gore-Tex shunt or band that was inserted at the last operation will be taken away.
In some centres the stump of the lower body vein (inferior vena cava) is attached to the base of the lung artery (pulmonary artery). This is known as the Hemi-Fontan operation. Although blood does not flow through this attachment at this time, it prepares the child for the completion of a Fontan procedure at Stage Three.
These operations have fewer risks than the first stage but it is important to talk with the medical team to find out the risks for your child.
The Fontan Procedure (Stage Three) for all single ventricle conditions or completion of the Cavo-Pulmonary Connection
The final stage of surgery will be performed as the child starts to show that they need more blood flow to the lungs. They may become more breathless on exercise or their growth may slow down. For some children this will occur before they start school. Others may be able to wait a little longer. For more information see the LHM booklet The Fontan.
The Fontan procedure aims to separate the blue (deoxygenated) blood supply and the red (oxygenated) blood supply. Although this does not make the heart function normal, it does allow the children to grow and enjoy more physical activity. The procedure can be performed in two ways.
External Fontan or External Conduit
This operation is done by attaching a tube of a special plastic (a conduit of Gore-Tex) from the lower body vein (inferior vena cava) to the base of the lung artery (pulmonary artery), diverting blue (deoxygenated) blood away from the heart straight to the lungs.
A hole (fenestration) may be created between the tube and the right collecting chamber (right atrium). As with the Internal Fontan (see below) there can be a rise in pressure in the lung arteries after surgery and the hole acts as a pressure valve.
Children may be in hospital for some weeks after the third operation as it is important to give them time to adjust to their new circulation.
This is done by creating a wall (baffle) in the right collecting chamber (right atrium) and then attaching the chamber to the base of the lung artery (pulmonary artery). This may have been partially completed at stage two, the Hemi-Fontan.
All the returning blue (deoxygenated) blood will now be flowing to the lungs, without a pump behind it. This causes an increase in pressure within the lung blood vessels, so, to aid circulation, a small hole (fenestration) may be created in the wall (baffle). This acts as a pressure release valve whilst the child’s body adjusts to the new circulation.
Updated: June 2017
Review due: June 2019