Tetralogy of Fallot Test

Tetralogy of Fallot Test What are the 4 components of the Tetralogy of Fallot - VSD, overriding aorta, pulmonary stenosis, and RV hypertrophy What is the embryological cause of TOF - Underdevelopment of the RV infundibulum or conus What is a Tet spell? - This is an episode of cyanosis caused by right to left shunting because of hypercontractility, often seen when patient is agitated Mc coronary anomaly in Tet - Left coronary from right What is a transannular patch - A patch that goes across the pulmonary valve annulus. Often used to make the RVOT wider when there was obstruction. What does RV function depend on in general - AV synchorny, adequate preload, low pulmonary vascular resistance Describe Tetralogy of Fallow with Absent Pulmonary Valve - Severe form of TOF in which the absence of a pulmonary valve leads to a lot of pulmonary regurgitation. This leads to very large aneurysms of the central pulmonary arteries which can lead to compression of the large central airways What is embryology of TOF with absent pulmonary valve - There is thought to be no ductus arteriosus which puts a lot stress on the wall of the central pulmonary arteries. How do you treat a tet spell? - Calm patient, Increase systemic resistance compared to pulm by putting patient in knee to chest position, phenylephrine, morphine, oxygen What are symptoms of Tet spells - Crying, inconsolable, hyperpnea, cyanosis What does murmur from Tet of Fallot come from - Pulmonary stenosis 4 components of TOF - 1) Infundibular pulmonary stenosis 2) conoventricular septal defect 3) malposition of the aorta so that the aorta root overrides the VSD 4) RVH What is thought to be the primary problem in TOF - Underdevelopment of the pulmonary infundibulum, with the other defects being secondary. The reason for this hypothesis is that the degree of aortic override is proportionate to the amount of pulmonary stenosis Are the pulmonary and aortic valves normal in TOF? - Pulmonary valve: often abnormal Aortic valve: sometimes has insufficiency because the aortic root is so dilated What are the 4 types of TOF - 1) Classic 2) TOF with pulmonary atresia 3) TOF with absent pulmonary valve 4) TOF with AV canal defect What are major problems with TOF with absent pulmonary valve - 1) Lots of pulmonary regurgitation 2) absent ductus 3) massively dilated pulmonary arteries 4) Bronchioles are obstructed by the pulmonary arteries which are either dilated or have abnormal branching patterns. This leads to air trapping and therefore it can be hard to ventilate them. 5) Bronchioles may also have intrinsic defects that make breathing difficult for these patients 6) The RV is often very dilated because of volume overload. Why are patients with TOF cyanotic - Because of Right to Left shunting through the VSD What determines the amount of right-to-left