Lecture 8- Congenital Heart Defects

Question 1

How are congenital heart defects classified?

Answer 1

According to whether the blood shunts from left to right or from right to left.

Acyanotic involves shunting from left to right and is so called as blood has been oxygenated

Cyanotic- involves shunting of blood from right to left and so bypasses pulmonary circulation. Caused by tetralogy of fallot, VSD and pulmonary stenosis

Question 2

atrial septal defects?

Answer 2

Results in raised right ventricular pressure and eventual right heart failure. Gets worse with age as the heart stiffens and will often present then.

Question 3

Ventricular septal defects?

Answer 3

Left to right shunt. Can be heard as blood squirts at high pressure. Will cause pulmonary hypertension as right sided pressure is raised

Question 4

Atrio-ventricular septal defect?

Answer 4

Defect allows blood from all three chambers to mix. Blood less oxygenated and so heart yomps harder to compensate. Left side of heart weakens and can lead to heart failure. Inability to pump strongly also leads to pulmonary hypertension.

Question 5

Cyanosis and congenital heart defects?

Answer 5

If congenital ok as body adapts to using 65% oxygen. If not congenital then at 95% oxygen could get serious problems

Question 6

What is coarction?

Answer 6

Congenital narrowing of a short section of the aorta

Question 7

Classifying congenital heart defects?

Answer 7

Acyanotic
Left to right shunts like ASD, VSD, PDA
Obstructive lesions like aortic and pulmonary stenosis as well as coarction of aorta and mitral stenosis

Cyanotic
Tetralogy of fallot such as VSD and pulmonary stenosis
Transposition of the great arteries, total anomalous pulmonary venous drainage and univentricular heart

Question 8

Tetralogy of fallot?

Answer 8

Caused by ventricular septal defect. Overriding aorta due to it not sitting where its supposed to. Pushes pulmonary artery and and can lead to right ventricle hypertrophy. If balanced tetralogy of fallot doesnt cause too many problems

Question 9

Tricuspid atresia?

Answer 9

Tricuspid valve fails to form so no blood into i right ventricle.

With a VSD blood will flow from left ventricle to right ventricle and supply pulmonary circuit that way.

If no VSD pulmonary blood flow is achieved through the ductus arteriosus

Question 10

Transposition of great arteries?

Answer 10

Aorta and pulmonary artery swapped around. Ok in utero due to ductus arteriosus but huge problems after birth when this closes. Not viable with life unless the two circuits communicate through atrial, ventricular or ductal shunts.

Surgery can swap back but requires coronary artery to be moved as well

Question 11

Hypoplastic left heart?

Answer 11

Underdeveloped left ventricle. Right to left shunt but then blood shunts from left to right due to pulmonary pressure. Right ventricle perfuses body. Depends on DA and atrial septal defect in order to be viable with life

Question 12

Pulmonary atresia?

Answer 12

Pulmonary valve doesnt form properly. Blood from right atrium shunted directly to left atrium and blood only reaches lungs through ductus arteriosus