.jpg)
Tetralogy of Fallot is the most common
heart defect in children. The condition causes mixing of oxygen-poor blood with
the oxygen-rich blood being pumped out of the heart and into the circulatory
system of blood vessels.
·
The blood leaving the heart has less
oxygen than is needed by the organs and tissues of the body, a condition called
hypoxemia.
·
Chronic (ongoing, long-term) lack of
oxygen causes cyanosis, a bluish color of the skin, lips, and membranes inside
the mouth and nose.
The normal heart works as follows:
·
The heart is made up of 4 chambers: 2
upper chambers called atria and 2 lower, larger chambers called ventricles.
Each atrium is separated from its paired ventricle by a valve.
·
The heart has a left and a right side.
The left and right sides of the heart are separated by a septum (wall). The
right side of the heart receives oxygen-depleted or blue blood returning by
veins (superior vena cava and inferior vena cava) from the body.
·
The blood flows from the right atrium
through the tricuspid valve into the right ventricle, which pumps it through
the pulmonic valve into the pulmonary artery, the main artery to the lungs.
·
In the lungs, the blood absorbs oxygen
and then returns to the left atrium through the pulmonary veins.
·
From the left atrium, the blood is
pumped through the mitral valve to the left ventricle. The left ventricle pumps
the blood out of the heart into the circulatory system via a large artery known
as the aorta.
·
The blood moves throughout the body,
supplying oxygen and nutrients to organs and cells.
·
Organs cannot work properly if they do
not receive enough oxygen-rich blood.
The 4 abnormalities (tetralogy) of the heart described by
Fallot include the following:
·
Right ventricular hypertrophy:
Narrowing or blockage of the pulmonary valve and/or muscle under the pulmonary
valve coming out of the right ventricle. This restriction to blood outflow
causes an increase in right ventricular work and pressure, leading to right ventricular
thickening or hypertrophy.
·
Ventricular septal defect (VSD): This is a hole in the heart
wall (septum) that separates the 2 ventricles. The hole is usually large and allows
oxygen-poor blood in the right ventricle to pass through, mixing with
oxygen-rich blood in the left ventricle. This poorly oxygenated blood is then
pumped out of the left ventricle to the rest of the body. The body gets some
oxygen, but not all that it needs. This lack of oxygen in the blood causes
cyanosis.
·
Abnormal position of the aorta: The
aorta, the main artery carrying blood out of the heart and into the circulatory
system, exits the heart from a position overriding the right and left ventricles.
(In the normal heart, the aorta exits from the left ventricle.) This is not of
major importance in infants.
·
Pulmonary valve stenosis (PS): The
major issue with tetralogy of Fallot is the degree of pulmonary valve stenosis,
since VSD is always present. If the stenosis is mild, minimal cyanosis occurs,
since blood still mostly travels to the lungs. However, if the PS is moderate
to severe, a smaller amount of blood reaches the lungs, since most is shunted
right-to-left through the VSD.
Tetralogy of Fallot Symptoms
Most infants with tetralogy of Fallot develop cyanosis in
the first year of life.
·
The skin, lips, and mucous membranes
inside the mouth and nose take on a noticeably dusky blue color.
·
Only some infants with very severe
obstruction of the right ventricle outflow turn blue at birth.
·
A small number of children with
tetralogy of Fallot never turn blue at all, especially if the pulmonary
stenosis is mild, the ventricular septal defect is small, or both.
·
In some children, the cyanosis is quite
subtle and may go undetected for some time.
The following symptoms suggest tetralogy of Fallot:
·
Growth and development are slower,
especially if the pulmonary stenosis is severe. Puberty may be delayed if the tetralogy is
untreated.
·
The child usually tires easily and begins
panting with any form of exertion. He or she may play for only a short time
before sitting or lying down.
·
Once able to walk, the child often
assumes a squatting position to catch his or her breath and then resumes
physical activity. Squatting increases the pressure transiently in the aorta
and left ventricle, causing less blood to move into the left ventricle, more
out the pulmonary artery to the lungs.
Medical Treatment
.jpg)
Surgery is the primary way to correct the heart problem.
Your child may be prescribed medication for tet spells. You will also be given
information for dealing with future tet spells.
·
The child will be placed on his or her
back in the knee-to-chest position to increase aortic resistance. The increased
aortic and left ventricular pressure reduces the rush of blood through the
septal hole from the right ventricle and improves blood circulation to the
lungs, so more red blood reaches the tissues.
·
The child may be given oxygen through a
face mask to increase the amount of oxygen in the blood.
No comments:
Post a Comment