Running head: TETROLOGY OF FALLOT
TETRALOGY OF FALLOT
Northern Essex Community College
NEONATAL & PEDIATRIC RESPIRATORY CARE
PROFESSOR MICHAEL CUSANO
November 14, 2018
TETRALOGY OF FALLOT
Tetralogy of Fallot is a complex condition that is a combination of several different congenital heart defects. This defect occurs in the first eight weeks of pregnancy when the heart does not form correctly in the womb and this affects normal blood flow through the heart. Tetralogy of Fallot (TOF or "TET") is a combination of four congenital heart defects, including:
- Ventricular septal defect (VSD) - an opening in the ventricular septum, or dividing wall between the two lower chambers of the heart known as the right and left ventricles.
- Pulmonary (or right ventricular outflow tract) obstruction - a muscular obstruction in the right ventricle, just below the pulmonary valve, that decreases the normal flow of blood. The pulmonary valve may also be small.
- Overriding aorta - the aorta is shifted towards the right side of the heart so that it sits over the ventricular septal defect.
- Right ventricle enlargement – the size of the right ventricle increases as it tries to pump blood past the obstruction into the pulmonary artery.
Normally, oxygen-poor (blue) blood returns to the right atrium from the body, travels to the right ventricle, then is pumped through the pulmonary artery into the lungs where it receives oxygen. Oxygen-rich (red) blood returns to the left atrium from the lungs, passes into the left ventricle, and then is pumped through the aorta out to the body. In tetralogy of Fallot, blood flow within the heart varies, and is largely dependent on the size of the ventricular septal defect, and how severe the obstruction in the right ventricle is.
· With mild right ventricle obstruction, the pressure in the right ventricle can be slightly higher than the left. Some of the oxygen-poor (blue) blood in the right ventricle will pass through the VSD to the left ventricle, mix with the oxygen-rich (red) blood there, and then flow into the aorta. The rest of the oxygen-poor (blue) blood will go its normal route to the lungs. These children may have slightly lower oxygen levels than usual, but may not appear blue.
· With more serious obstruction in the right ventricle, it is harder for oxygen-poor (blue) blood to flow into the pulmonary artery, so more of it passes through the VSD into the left ventricle, mixing with oxygen-rich (red) blood, and then moving on out to the body. These children will have lower than normal oxygen levels in the bloodstream, and may appear blue, especially whenever the pressure in the right ventricle is very high and large amounts of oxygen-poor (blue) blood passes through the VSD to the left side of the heart.
Tetralogy of Fallot occurs in about two out of every 10,000 live births. It makes up about 8 percent of all cases of congenital heart disease. Tetralogy of Fallot occurs equally in boys and in girls...