Pulmonary Stenosis (PS) - Pulmonary stenosis causes an obstruction of blood flow from the right ventricle to the pulmonary arteries. This obstruction causes the right ventricle to have a harder time pumping oxygen-poor blood received from the vena cava to the lungs to pick up needed oxygen. Thus causing a decrease in oxygen exchange in the lungs, as well as a decrease in blood volume to the lungs.3. Priority aorta – Due to the alignment of the ventricular septum and the formation of the VSD, the aorta is positioned “directly above the aorta. Both the right and left ventricles have access to the aorta causing increased blood outflow through the aorta. Due to pulmonary stenosis in the pulmonary arteries, blood flow to the lungs will be obstructed causing blood to back up to the right ventricle and aorta; mixing oxygenated blood with deoxygenated blood that goes to the body tissues.4. Right ventricular hypertrophy (RVH) – In a normal heart, the left ventricle has a somewhat thicker wall than the right because it has to pump oxygenated blood to the body unlike the right ventricle which has to pump only deoxygenated blood to the lungs. However, Tetralogy of Fallot causes enlargement of the right ventricular muscle due to pulmonary stenosis in the