Tetralogy of Fallot is a complex congenital heart defect. It is characterized by four anatomical malformations of the heart. It is a heart anomaly that leads to an undersupply of oxygen to the body organs and therefore to cyanosis.
Here you will find further information as well as selected specialists and centers for tetralogy of Fallot.
Many babies and children born with tetralogy of Fallot have a bluish skin color, especially on the
This is why tetralogy of Fallot was also called "blue baby disease".
At 70 percent, tetralogy of Fallot is the most common of all heart defects leading to cyanosis (cyanotic heart defects). With an incidence (occurrence) of 1:3600, it accounts for around six to eight percent of all congenital heart defects. Boys are affected slightly more frequently than girls.
Tetralogy of Fallot is due to a maldevelopment of the vascular system during the embryonic period. Until the fifth week of development, theaorta and the pulmonary artery together form the outflow tract of the heart. After this, a septum (aorticopulmonary septum) forms, which separates the two arteries.
In a tetralogy of Fallot, this septum is offset. The pulmonary artery leading from the right ventricle is narrowed as a result.
This displacement results in the anatomical malformations characteristic of tetralogy of Fallot:
Illustration of a heart affected by tetralogy of Fallot next to a healthy heart © Mariana Ruiz | Wikimedia
Normally, the aorta originates from the left ventricle. It runs down through the chest and abdomen and supplies the body's organs with oxygen.
In tetralogy of Fallot, the aorta lies above the right ventricle due to the improper separation. The aorta virtually "rides" over the hole in the cardiac septum. As a result, it also receives blood from the right ventricle.
This blood should actually pass through the pulmonary circulation and be enriched with oxygen. It is therefore low in oxygen. In addition, the pulmonary artery is narrowed so that less blood reaches the lungs for oxygenation.
In summary, this means that less oxygen is transported into the body via the blood than normal. The severity of the tetralogy and thus the blue coloration of the skin and mucous membranes depends on this,
What triggers the underlying maldevelopment of the vascular system is not yet fully understood. Around 32 percent of those affected have genetic abnormalities, such as trisomy 21 (Down syndrome). A genetic component is therefore assumed. In addition, the risk of recurrence in children of affected parents is estimated at 1.2 to 8.3 percent.
The symptoms are largely dependent on the extent of the four characteristic malformations. They can vary greatly from person to person. One tetralogy is not exactly like another.
If the narrowing of the pulmonary artery is only mild to moderate, sufficient deoxygenated blood reaches the lungs. The affected children do not usually exhibit the typical cyanosis.
If the narrowing is severe, however, there is an undersupply of oxygen. This also causes the characteristic blue coloration of the skin and mucous membranes.
Newborns and infants are usually characterized early on by
on the lips and tongue. The blue coloration can intensify, especially when crying.
In addition, respiratory distress and limited performance are already apparent in the first year of life. Children also often adopt a squatting position (knees to chest). This position improves the body's oxygen saturation.
The outflow tract of the right ventricle can close completely during strong excitement and strong and prolonged crying. This can lead to an attack(hypoxemia) with
and unconsciousness. A hypoxemic seizure requires emergency medical treatment. In this case, parents of affected children should
In recent years, early surgical correction of anatomical malformations has become established.
However, the optimal time for such an intervention is still the subject of controversy. According to comparative studies, this is on average between the fourth and twelfth month of life.
The aim of the correction is to remove the hole in the cardiac septum and offset the septum.
This heart surgery is performed using a heart-lung machine. The surgeon first closes the hole in the cardiac septum. To do this, he uses a patch made of Gore-Tex material or a small piece of the child's pericardium (patch closure).
He then removes the constricting muscle tissue (myectomy). Finally, the outflow tract is widened below the valve ring with another sewn-in patch.
If the pulmonary artery is also too narrow, it is also widened using a patch.
If the valve ring is severely narrowed, it must be cut, bent open and enlarged again with a large patch. The patch extends from the wall of the ventricle over the open valve ring and into the pulmonary artery. This maneuver is also known as transannular patch dilatation surgery.
In some cases, it is necessary to replace parts of the pulmonary artery and its valve. If such a primary total correction is not possible, palliative measures are indicated. These are aimed at improving the pulmonary circulation.
The pulmonary circulation can be improved by medication, surgery or with the help of a catheter.
