8. Congential Heart Defects

Question 1

What can cause congenital heart defects?

Answer 1

Genetic: Downs, Turners, Marfan’s, or polygenic
Environmental: drugs, alcohol
Maternal infections: rubella, toxoplasmosis

Question 2

What happens in a left to right shunt?

Answer 2

Blood from left heart is returned to lungs instead of going to body
Requires a hole

Question 3

Why is a left to right shunt bad?

Answer 3

Increased lung blood flow by itself I’d not damaging, but increased pulmonary artery or pulmonary venous pressure is

Question 4

What is a right to left shunt?

Answer 4

Requires a hole and distal obstruction

Deoxygenated blood bypasses the lungs

Question 5

What are the 2 classes of congenital defects?

Answer 5

Acyanotic - pink

Cyanotic - blue (circulating blood deoxygenated)

Question 6

What are the acyanotic congenital heart diseases?

Answer 6

Left to right shunts (ASD, VSD, PDA)

Obstructive lesions: aortic stenosis, pulmonary stenosis, coarctation of the aorta, mitral stenosis

Question 7

What are cyanotic congenital heart defects?

Answer 7

Complex, right to left shunts
Tetralogy of fallot
Transposition of great arteries
Total anomalous pulmonary drainage
Univentricular heart

Question 8

What shunts may be present?

Answer 8

Atrial
Ventricular
Atrioventricular
Aortopulmonary (ductal)

Question 9

Where can atrial septal defects be?

Answer 9

Sinus venous
Secundum atrial
Primum atrial

Question 10

What are the haemodynamic effects of atrial septal defects?

Answer 10

Increased pulmonary blood flow (low pressure)
RV volume overload
Sometimes pulmonary hypertension
Eventual right heart failure

Question 11

What are the haemodynamic effects of ventricular septal defects?

Answer 11

Left to right shunt
LV volume overload
Pulmonary venous congestion
Eventual pulmonary hypertension

Question 12

What is coarctation?

Answer 12

Aortic narrowing that occurs at or near the aortic arch

Question 13

What makes up a tetralogy of fallot?

Answer 13

Ventricular septal defect
Over-riding aorta
Pulmonary stenosis
Right ventricular hypertrophy

Question 14

What is tricuspid atresia?

Answer 14

No RV inlet
R to L atrial shunt of entire venous return
Blood flow to lungs via VSD or PDA

Question 15

What is transposition of the great arteries?

Answer 15

RV connected to aorta
LV connected to pulmonary artery
Not viable unless the two circuits communicate i.e. via atrial, ventricular or ductal shunts
Bi directional shunting

Question 16

What is hypoplastic left heart?

Answer 16

Left ventricle is underdeveloped
Ascending aorta very small
Right ventricle supports systemic circulation 
Obligatory right to left shunt 
Must be ASD and PDA

Question 17

What is pulmonary atresia?

Answer 17

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

Question 18

What is the natural history of ASD?

Answer 18

Usually asymptomatic late into adulthood

Lat onset arrhythmia and right heart failure

Question 19

What is atrial history of VSD?

Answer 19

Unless very small, present in infancy with left heart failure
Untreated, can lead to in-operable pulmonary hypertension

Question 20

What is the neural history of coarctation?

Answer 20

Neonatal variety: associated with PDA, R to L shunt

Adult variety: complicated by renal hypertension, often associated with aortic valve stenosis

Question 21

What is natural history of tetralogy of fallot?

Answer 21

Present in infancy or early childhood with cyanotic spells

Mild cases compatible with adulthood

Question 22

Which congenital heart diseases present as neonatal emergencies from reduced pulmonary blood flow?

Answer 22

Transposition
Hypoplastic left heart
Pre-ductal coarctation
Pulmonary atresia