Congenital Heart Disease

Question 1

Describe morphology of the RA?

Answer 1

Contains the SA node

Broad appendage

Question 2

Describe morphology of the LA?

Answer 2

Narrow, long appendage

Question 3

Describe morphology of the RV?

Answer 3

Trabeculated endocardium
Insertion of the chordae to the IV septum
Thick moderator band muscle.

Question 4

Describe morphology of the LV?

Answer 4

Smooth endocardium, ellipsoid cavity.

Question 5

What is the most common atrial septal defect?

Answer 5

Secundum

Question 6

How does a secundum ASD occur?

Answer 6

When foramen ovale fails to close leaving a hole between atria.

Question 7

What happens to blood in a secundum ASD?

Answer 7

Blood can mix and normally shunts left to right.

Question 8

How could you identify a secundum ASD on examination?

Answer 8

Pulmonary flow murmur

Fixed split second heart sound.

Question 9

What other heart problems can a secundum ASD lead to?

Answer 9

• RV failure as RV receives blood from both atria and becomes dilated.
• Atrial arrhythmias such as AF.
• Tricuspid regurgitation.

Question 10

What other non-heart problems can a secundum ASD cause?

Answer 10

• Pulmonary hypertension
• Eisenmenger Syndrome
• Stroke

Question 11

How are secundum ASD’s treated?

Answer 11

Surgery via sternotomy or transcatheter approach from groin.

Question 12

What is transposition of the great arteries?

Answer 12

Where they aorta and pulmonary artery switch.
Aorta is connected to the RV
Pulmonary artery now connected to the LV.
2 separate circulation systems exist.

Question 13

Is transposition of the great arteries a cyanotic condition?

Answer 13

Yes - incompatible with life.

Question 14

What is the M:F ratio for transposition of the great arteries?

Answer 14

4:1

Question 15

What immediate treatment is given to babies with transposition of the great arteries? Why?

Answer 15

When born, the foramen ovale and ductus arteriosus close over the first hours of life. When this occurs in this condition, 2 seperate circulation systems are created and there is a seperate systemic and pulmonary circulation therefore the blood travelling round the body is deoxygenated.
We give prostaglandins to maintain these structures to allow mixing of blood so oxygenated blood can also get into the systemic circulation. This buys times.

Question 16

Describe long term treatment options for transposition of the great arteries?

Answer 16

Atrial switch: Creates a baffle (tunnel) between atria so blood can mix

Arterial switch: Cut pulmonary artery and aorta above valves and switch them to resemble normal anatomy.

Question 17

Discuss problems with surgery for transposition of the great arteries?

Answer 17

Atrial switch: Issue as RV isnt made to provide systemic circulation so it dilates. This can also stretch the tricuspid valve and cause regurgitation.
Stretched atria can also cause atrial arrrhythmias.

Arterial switch: Coronary arteries are attached to the pulmonary artery so need switched also. They can become disrupted or occluded by surgery causing cardiac perfusion problems.

Question 18

What are the features of tetralogy of Fallot? list only.

Answer 18

1. Ventricular septal defect.
2. Overriding aorta.
3. RVOT obstruction.
4. RV hypertrophy.

Question 19

What is the result of the features in a tetralogy of Fallot?

Answer 19

1. VSD: mixing of blood down pressure gradient from left to right.
2. Overriding aorta: Aorta pulled towards RV and sits above septum. Mixed blood goes up aorta causing cyanosis.
3. RVOT obstruction: Due to no pulmonary valve or bulky muscle mass under the valve. Causes restricted blood flow to the pulmonary arteries.
4. RV hypertrophy: Due to RV working harder.

Question 20

What are the treatment options for tetralogy of Fallot?

Answer 20

BT shunt: use subclavian or carotid artery and plumb into the pulmonary artery to improve blood supply to the lungs. Can now use goretex tubes to do the same.

Patch: used to close septal defect.

Can cut away bulk affecting pulmonary valve.

As lung arteries are under-developed can enlargen (using patch???)

Question 21

Highlight some post-surgical problems in tetralogy of fallot?

Answer 21

• Over time surgery tires. May leads to pulmonary regurgitation and RV dilatiation.
  (combat this by valve replacement).
• Arrhythmia as increased RV pressure causes increased RA pressure and RA dilates to cope. Dilation can be vunerable to tachycardiac arrhythmias.
• Pulmonary artery stenosis.

Question 22

What is a univentricular heart?

Answer 22

Heart with only one ventricle.

Relies on shunt for mixing of blue and red blood.

Question 23

Why does a univentricular heart occur?

Answer 23

Many reasons, most common is tricuspid atresia.

Question 24

How is a univentricular heart treated?

Answer 24

Aim to make 2 ventricles, but irregular anatomy may not allow for this.
Can create Fontan circulation.
- IVC and SVC are plumbed directly into the pulmonary arteries.

Question 25

What are the issues with Fontan circulation?

Answer 25

Without an RV to pump blue blood to pulmonary circulation, we rely on high systemic pressure to drive blood to pulmonary arteries. This is a vunerable balance. Any pressure changes could cause haemodynmic compromise, for example.. - arrhythmias - dehydration - PE - blood loss

Question 26

What drug are all patients with fontan circulation on?

Answer 26

Anti-coagulants.

Question 27

How does a foetus receive oxygenated blood?

Answer 27

From the placenta.

Question 28

What 2 important structures are present in foetal hearts?

Answer 28

Foramen ovale | Ductus arteriosus

Question 29

Describe foeal circulation in relation to these structures?

Answer 29

Because the lungs are not fully formed, vascular resistance in the pulmonary arteries is high. Therefore blood from IVC takes the path of least resistance and passes through the foramen ovale to the LA. A small amount of blood goes through the RV to the pulmonary vein, but nearly all passes through the ductus arteriosus to the aorta.

Question 30

When do the foramen ovale and ductus arteriosus regress?

Answer 30

When baby takes first breath, pressure changes in the heart and the lungs. Over the next few hours these structures close.

Question 31

What is co-arctation of the aorta?

Answer 31

Congenital narrowing of the aorta.

Question 32

Where does co-arctation normally occur?

Answer 32

after the left subclavian artery in a juxta-ductal position.

Question 33

What happens to the LV in co-arctation of the aorta?

Answer 33

LV has to pump harder to force blood through narrowing. This causes LV hypertrophy. If not corrected = LV failure

Question 34

Why do co-lateral vessels form in co-arctation of the aorta?

Answer 34

As blood tries to take the path of least resistance so tries to find alternative ways to by pass the narrowing.

Question 35

If severe co-arctation is severe, what signs would you see?

Answer 35

- cold feet - claudication - abdominal angina - upper body hypertension: BP in arms is greater than the legs - radio-femoral pulse delay - headaches - berry aneurysms - renal insufficency.

Question 36

What signs on x-ray would indicated co-arctation?

Answer 36

Rib notching due to retrograde flow from anterior intercostal arteries to low pressure posterior arteries.

Question 37

What would you hear on auscultation of a co-arctation?

Answer 37

Narrowing cause turbulent flow which can be heard as a continuous murmur on the front and back of chest.

Question 38

What treatments can be offered for co-arctation?

Answer 38

Surgical - Subclavian artery flap - Resection of narrowing and anastamose ends (this is used now!) Transcatheter - Use balloon via femoral artery to dilate narrowing.