Tetralogy of Fallot (TOF)
Tetralogy of Fallot (TOF) is a complex congenital heart malformation
consisting of an opening in the wall between the lower heart chambers, a
narrowing of the pulmonary valve and the muscular area just beneath it,
thickening of the right ventricle, and abnormal position of the great artery
(aorta). The combination of these four heart defects comprises the condition
called tetralogy of Fallot. The result is that blue blood from the right
ventricle is partially blocked from getting to the lungs. Instead, some blood
can go through the VSD and out the overriding aorta to the body.
Symptoms of the condition
Children may appear cyanotic, which is the discoloration of the skin and
mucous membranes due to deficient oxygenation of the blood. The child will not
appear as pink as normal; his or her skin, lips and nails will appear to have a
bluish color. Another more serious symptom and event is called a “Tet
spell,” something that is sometimes seen in children with severe TOF. In a
“Tet spell,” the extra muscle in the heart below the pulmonary valve may squeeze
down tightly, allowing very little blood to get to the lungs. The
baby becomes irritable and very blue, breathes very fast and may even pass
out. If this happens, it is essential to bring the baby's knees all the way up
to his chest, call 911 and alert the doctor immediately. A “Tet spell” can be
very dangerous for the baby and may require urgent surgery.
Treatment for TOF
If the branches of the pulmonary artery are close to normal size, this operation
can be done in one step. If,
however, the pulmonary arteries of the baby are too small, an additional
procedure may be needed first to help the blood vessels grow to a more
normal size. Complete repair of
TOF is usually done in the first year of life. It consists of patch closure of the VSD so
that the aorta arises solely from the left ventricle, as well as enlarging the
right ventricle outflow tract, pulmonary valve, and branch pulmonary arteries as much as
possible.