NGR 5141 - Module 8 QUESTIONS AND ANSWERS. LATEST 2023

A neonate has a harsh, loud, systolic murmur shortly after birth. This is best heard at the left lower sternal border. The neonate is acyanotic and has no other symptoms. What type of congenital heart disorder does this infant have? Explain why the neonate is not cyanotic. When could the infant become cyanotic? This infant has a ventricular septal defect (VSD). This is an abnormal communication between the ventricles. The VSD allows a large amount of shunting from left to right. The shunted blood then goes directly out the right ventricle outflow tract and into the pulmonary artery instead of the right ventricle cavity. Cyanosis does not occur because the pulmonary artery, left atrium, and left ventricle all enlarge which causes left ventricle hypertrophy so that the heart can pump the rest of the volume adequately. The pulmonary system is also effected since there is increased blood flow due to the left to right shunting. The smooth muscle layer in the arteriolar walls thickens which causes a lessening of the diameter of the pulmonary vessels which in turn, increases blood flow resistance. However, if the systemic vascular resistance is exceeded, the shunt through the VSD is reserved and deoxygenated blood is allowed to flow into the systemic circulation. This would cause the infant to become cyanotic and it termed Eisenmenger syndrome. 2. Why do children with tetralogy of Fallot have cyanosis? Why do they squat? Explain the pathophysiology and anatomic features involved. Tetralogy of Fallot has four