Congenital Heart Disease Flashcards
What could cause a congenital heart disease?
Genetic - Down’s, Turner’s, Marfan’s
Environmental - Teratogenicity from drugs, alcohol ect..
Maternal infections - Rubella, Toxoplasmosis ect..
How are the left and right ventricle different?
Right ventricle wrap around left. -
They are morphologically adapted for their tasks.
For example, the left ventricle is thicker and more muscular because it pumps blood at a higher pressure. The left also forms the apex of the heart.
What is the oxygen saturation of deoxygenated blood?
67% (ish)
What are the effects of left to right shunt?
Required a hole!
Blood from the left heart is returned to the lungs instead of going to the body.
Increased lung blood flow by itself is not damaging but increased pulmonary artery or pulmonary venous pressure is.
What are the effects of a right to left shunt?
It required a hole and distal obstruction
De-oxygenated blood bypasses the lungs.
Results in cyanosis at birth so can lead to perinatal death unless corrected surgically. Most common is tetralogy of fallot.
ASV VSD If pressure increased in right side
What is cyanosis? List some cyanotic congenital heart diseases.
It is the bluish discolouration of the skin due to blood having low oxygen saturation. Cyanotic defects are complex and occur with left to right shunts. Cyanosis occurs in:
- Tetralogy of Fallot
- Transposition of the great arteries
- Total anomalous pulmonary venous drainage
- Univentricular heart
What is acynosis? List come acynotic congenital heart defects.
This is when cyanosis does not occur. It occurs in:
Left to right shunts: ASD, VSD, PDA
Obstructive lesions: Aortic stenosis (hypoplasia), Pulmonary stenosis (Valve outflow, branch). Coarctation of the Aorta, Mitral stenosis
What are atrial septal defect?
This is an opening in the wall / septum between the two atria which persists following birth. Because presssure is higher in the left side, blood will usually flow from left to right.
As ASD most commonly occurs as an ostium secundum atrial septal defect. This arises because of enlarged foramen ovale, inadequate growth of the septum secundum or the excessive absorbtion of the septum premium.
What are the haemodynamic effects of atrial septal defects?
- Increased pulmonary blood flow
- RV Volume overload
- Pulmonary hypertension is rare
- Eventual right heart failure
What is a patent foramen ovale?
This is not a true ASD. PFOs may be present in around 20% of the population and are generally clinically silent since the higher left atrial pressure causes functional closure of the flap valve.
What are ventricular septal defects?
It is an abnormal opening in the interventriculae septum. This most commonly occurs in the membranous part of the septum but can occur at any point.
It is a left to right shunt and it causes:
- LV Volume overload
- Pulmonary Venous congestion
- Eventual pulmonary hypertension
What is coarctation?
Congenital narrowing of of the aortic lumen in the region of the ligamentum arteriosum (former ductus arteriosus). This leads to afterload on the left ventricle and can lead to left ventricular hypertrophy.
Blood flow to the head and upper limbs is not comprimised because the vessle supplying this usually emerges proximally to the coarctation. But, blood flow to the rest of the body is reduced.
What is tetralogy of Fallot?
This is a group of four lesions occuring together as a result of a single developmental defect which places the outflow portion of the interventricular septum too far un the anterior and caphalid region.
The four defects are:
- Pulmonary stenosis - causes persistance of right ventricle hypertrophy as RV must operate at a higher pressue to pump blood through PA.
- Ventricular septal defect
- Right ventricular hypertrophy
- Over-riding aorta
Cyanosis occurs in this condition. This occurs as a result of increased pressure on the right hand side, VSD and overriding aorta. The severity depends in the severity of the pulmonary stenosis.
What is tricuspid Atresia?
This is a lack of development of the tricuspid valve. This leaves no right ventricle inlet. There must be a complete right to left shunt of all the blood returning to the right atrium (ASD or PFO) and a VSD or PDA to allow blood flow to the lungs.
What is transposition of the great arteries?
The right ventricle is connected to the aorta and the left ventricle is connected to the pulmonary artery.
This results in two unconnected parallel circulations instead of two circulations in series.
It is not viable unless the two circuits communicate ie via atrial ventricular or ductal shunts. It is an example of bi-directional shunting.
