Congenital Heart Defects

Question 1

Describe aetiology of congenital heart disease.

Answer 1

Genetic- Down’s, Turner’s and Marfan’s syndrome. Environmental- teratogenicity from drugs, alcohol etc. Maternal infections- rubella, toxoplasmosis, etc.

Question 2

Describe the pathophysiology of CHD.

Answer 2

Right ventricle pumps deoxygenated blood to lungs. Pulmonary circulation has low resistance. Left ventricle pumps oxygenated blood at systemic blood pressure to aorta. Each ventricle is morphologically adapted for its task.

Question 3

Describe the classification of acyanotic CHD,

Answer 3

Left to right shunts: ASD, VSD, PDA. Obstructive lesions: aortic stenosis, pulmonary stenosis, coarctation of aorta, mitral stenosis.

Question 4

Describe the classification of cyanotic CHD.

Answer 4

Tetralogy of Fallot, transposition of great arteries, univentricular heart.

Question 5

Describe left to right shunt requirements.

Answer 5

Requires a hole, blood from left heart is returned to the lungs instead of going to the body.

Question 6

Describe right to left shunt requirements.

Answer 6

Requires a hole and distal obstruction, de-oxygenated blood bypasses lungs.

Question 7

Describe the haemodynamic effects of ASD.

Answer 7

Increased pulmonary blood flow, RV volume overload, pulmonary hypertension is rare, eventual right heart failure.

Question 8

Describe the haemodynamic effects of VSD.

Answer 8

Left to right shunt, LV volume overload, pulmonary venous congestion, eventual pulmonary hypertension.

Question 9

What is the Tetralogy of Fallot?

Answer 9

POSH: Pulmonary stenosis, Overriding aorta, ventricular Septal defects, right ventricular Hypertrophy

Question 10

Describe the patho-physiology of Tricuspid Atresia.

Answer 10

No RV inlet, R to L atrial shunt of entire venous return, blood flow to lungs via VSD (or PDA).

Question 11

Describe the transposition of the Great Arteries.

Answer 11

1. RV connected to aorta. 2. LV connected to pulmonary artery. 3. Not viable unless the two circuits communicate. 4. Example of bi-directional shunting.

Question 12

Describe hypoplastic left heart.

Answer 12

1. LV is underdeveloped. 2. Ascending aorta is very small. 3. RV supports systemic circulation. 4. Obligatory right to left shunt.

Question 13

Describe the patho-physiology of pulmonary atresia.

Answer 13

No RV outlet, R to L atrial shunt of entire venous return, blood flow to lungs via PDA.