Atrial septal defects

Question 1

How common is it that an infant will be born with significant cardiac malformations?

Answer 1

8 per 1000 live born infants

(1-2% of live births will have some abnormality of the cardiovascular system)

Question 2

What is ASD?

What are the two different types?

Answer 2

An artial septal defect

Two types:

• A secundum ASD (80%)
• Partial AVSD

Question 3

What is the difference between a secundum ASD and a partial AVSD?

(in terms of symptoms and anatomy)

Answer 3

• Both present with similar symptoms but very different anatomy

Secundum ASD

• Is a defect in the centre of the artial septum involving the the foramen ovale

Partial AVSD

• Is a defect of the artioventricular septum
• Characterised by an inter-artial communication between the bottom end of the artial septum and the artrioventricular valves

Question 4

Symptoms for an ASD?

Physical signs?

Answer 4

Symptoms:

• Commonly none
• Recurrent chest infections/wheeze
• Arrhythmias (4th decade onwards)

Signs:

• An ejection systolic murmer best heard at the ULSE (due to increased flow across the pulmonary valve because of the left to right shunt)
• A fixed and widely spilt second heart sound (hard to hear)
• With a partial AVSD an apical pansystolic murmer may be heard

Question 5

What investigations would you do for a patient with a secundum ASD or partial AVSD? (3)

What would they show?

Answer 5

Chest x-ray:

• Cardiomegaly
• Enlarged pulmonary arteries
• Increased pulmonary vascular markings

ECG:

• Secundum ASD
  
  • Partial RBBB
  • Right axis deviation due to right ventricular enlargement
• Partial AVSD
  
  • A ‘superior’ QRS axis (largely negative in AVF) due to the defect being near the AV node

Echocardiogram:

• Will show anatomy ad is the mainstay of diagnostic investigations

Question 6

How should a child with a secundum ASD be managed?

Answer 6

If defect large enough it will cause right ventricular dilation will require treatment

Treatment:

• Cardiac catheterisation with the insertion of an occulsion device

Question 7

How should a child with a partial AVSD be managed?

At what age and why?

Answer 7

If defect large enough it will cause right ventricular dilation will require treatment

Treatment:

• Surgical correction is required
• Usually undertaken at about 3-5 years in order to prevent right heart failure and arrhythmias in later life