Birth Defect: Tetralogy of Fallot
Tetralogy of Fallot (te – tra – lo – je of fah – low) is a congenital heart defect – a heart defect that is present at birth – and occurs in approximately 5 out of every 10,000 babies. It is the most common heart defect in children.
A normal heart comprises four chambers: two upper chambers (atria) and two lower larger chambers (ventricles). The atria are separated from the ventricles by a valve. There is one upper chamber and one lower chamber on each side of the heart. Both sides of the heart are separated by a wall (septum). The right atrium receives oxygen-poor blood from the body, which then flows to the right ventricle and is pumped to the lungs through the pulmonary artery. Oxygen-rich blood then flows back through the pulmonary veins to the left atrium, then into the left ventricle where it is pumped to the rest of the body via the aorta. Without oxygen, organs and muscles cannot function normally.
Tetralogy of Fallot happens when four particular defects happen at one time:
- Ventricular Septal Defect (VSD) – The wall that separates the two lower halves of the heart – which normally prevents the mixing of blood from both sides of the heart –is called the ventricular septum. With VSD, there is a hole in the septum. When this happens the oxygen-rich blood from the left ventricle mixes with the oxygen-poor blood from the right ventricle.
- Pulmonary Stenosis – In pulmonary stenosis, the pulmonary valve, which normally allows blood to flow from the right ventricle to the pulmonary artery, does not fully open usually due to an obstruction. This means the heart has to work harder to pump blood through the valve and that not enough blood reaches the lungs to be oxygenated.
- Right Ventricular Hypertrophy – In right ventricular hypertrophy, the muscle of the right ventricle is thicker than normal because of all the extra work it has to do to move blood through the narrower pulmonary valve.
- Overriding Aorta – “In a healthy heart, the aorta is attached to the left ventricle. This allows only oxygen-rich blood to flow to the body. In tetralogy of Fallot, the aorta is located between the left and right ventricles, directly over the VSD. As a result, oxygen-poor blood from the right ventricle flows directly into the aorta instead of into the pulmonary artery.” (NHLBI)
Symptoms of Tetralogy of Fallot
Depending on the exact extent of the defects, a baby born with tetralogy of Fallot may not present with any obvious symptoms. If there are symptoms, they may include:
- Bluish tinge to the skin (cyanosis)
- Shortness of breath and rapid breathing, particularly during feeding
- Fainting spells
- Clubbing of fingers and toes (rounded shape of the nail bed)
- Poor weight gain
- Fatigue during play
- Prolonged crying
- Heart murmur
“Tet spells” are often the most common sign if a baby isn’t diagnosed right away. Tet spells are caused by a rapid drop in the amount of oxygen in the blood and typically happen after a bowel movement, during feeding, after crying or kicking. They are more common in infants 2 to 4 months old.
If your baby starts displaying any of these symptoms, place your child on his/her side and pull his/her knees up to the chest to increase the blood flow to the lungs and then call 9-1-1.
Treatment for Tetralogy of Fallot
Treatment for tetralogy of Fallot usually involves open-heart surgery, but may involve an initial non-open-heart surgery as well, depending on the particular case. One is a temporary solution, the other a complete repair of the heart.
In the temporary procedure, a shunt is placed to allow blood to flow from the pulmonary artery to the aorta to supply the rest of the body with oxygenated blood.
The complete repair procedure closes the VSD with a patch, removes some of the thickened muscle below the pulmonary valve to open the right ventricular outflow, repairs or removes the obstructed pulmonary valve, and, if necessary, enlarges the pulmonary arteries going to each lung.
The main long-term issue for children with tetralogy of Fallot following surgery is limited physical activity. “If the tetralogy has been repaired with surgery, and there’s no obstruction or leak in the pulmonary valve, your child may be able to participate in normal activities without much increased risk. Your child’s pediatric cardiologist will help decide if your child needs limits on physical activity.” (AHA)
Darlene Oakley is a freelance writer for EmpowHER.com.
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Tetralogy of Fallot. PubMed Health U.S. National Library of Medicine. Web. Mar 26, 2012.