Congenital Heart Defects - Patent Ductus Arteriosus

Question 1

When does the patent ductus arteriosus begin to close?

Answer 1

Normally stops functioning within 1-3 days of birth + closes within the first 2-3 weeks of life

Question 2

Auscultation sounds

Answer 2

Small may not have any abnormal heart sounds
Most significant = continuous crescendo-decrescendo “machinery” murmur that may continue during the second heart sound, making the second heart sound difficult to hear.

Question 3

Aetiology/ Risk Factors

Answer 3

Reasons why it fails to close are unclear:
- may be genetic
- repeated to maternal infections (e.g. rubella)
- PREMATURITY = key risk factor

Question 4

Pathophysiology

Answer 4

Pressure in aorta higher than pressure in pulmonary vessels, so blood flows from the aorta to the pulmonary artery = left to right shunt = pulmonary hypertension + right sided heart strain = right ventricular hypertrophy
Can lead to Eisenmengers syndrome

Question 5

Symptoms

Answer 5

Lower respiratory tract infection
SOB
Poor weight gain
Difficulty feeding
Occasionally patient can remain asymptomatic throughout childhood with signs of heart failure

Question 6

Signs

Answer 6

Cyanosis of lower extremities
Tachycardia
Continuous crescendo-decrescendo “machinery” murmur
Bounding pulse

Question 7

Investigations

Answer 7

FIRST LINE = ECHO
CXR
ECG

Question 8

Management

Answer 8

Patients are typically monitored until 1 year of age using echo
After 1 year = highly unlikely PDA will close