Cardiac Abnormalities

Question 1

Cardiac Abnormalities

Answer 1

• To understand cardiac abnormalities we’ll
look at the requirements for foetal and
neonatal circulation compared to the adults
• These requirements are met during normal
heart development
• Failure in development or failure in the
transition from foetal to neonatal circulation
can result in a cardiac abnormality

Question 2

Ventricular septal defect

Answer 2

The top part of the inter ventricular septum fails to form. More blood from the left side moves into the right than vice versa due to left side muscularity.

Question 3

Coarctation of the aorta

Answer 3

Narrowing of the aorta puts pressure on the left ventricle.
• narrowing of the aorta near
the ductus arteriosus
• muscle that closes the
ductus arteriosus has
extended around the aorta
• constriction occurs at birth
• may be pre- or post-ductal
coarctation
• if post-ductal may cause patent ductus arteriosus
• 6% of heart defects and 3x more common in males
• coarctation encourages collateral circulation
• subclavian arteries may take blood to lower body

Question 4

Tetralogy of Fallot

Answer 4

Multiple defects (4)
1 pulmonary trunk too narrow and valve stenosed. = 2 hypertrophied right ventricle. 3 ventricular septal defect and 4 aorta opens from both ventricles.

There is flow of deoxygenated (blue) blood into the general body
circulation and decreased blood flow to the lungs.

Question 5

Cyanotic

Answer 5

• Cyanotic abnormalities are when
deoxygenated blood enters the systemic
circulation
Cyanotic Abnormalities
– Tetralogy of Fallot
– Transposition of the Great Vessels

Question 6

Acyanotic

Answer 6

• Acyanotic abnormalities are when
oxygenation of the systemic circulation is
relatively normal (some oxygenated blood
may re-enter the pulmonary circulation)
• Acyanotic abnormalities include:
– Ventricular septal defects (VSDs)
• the left ventricle has a higher pressure
than the right so oxygenated blood
enters the right side of the heart to
returned to the lungs
– Atrial septal defects (ASDs)
– Aortic stenosis
– Coarctation of the Aorta

Question 7

Patent Ductus Arteriosus

Answer 7

• blood will flow from the
higher pressure aorta to the
lower pressure pulmonary
artery
• this will reduce blood flow via
aorta to systemic circulation
• increase blood flow to lungs
may cause pulmonary
oedema resulting in right
sided heart failure
• 12% of all heart defects and
2-3 x more common in
females

Question 8

Formation of the Aorta and Pulmonary Artery

Answer 8

• failure to spiral will result in
transposition of the great
vessels
• failure to divide equally will
result in a stenotic (narrowed)
aorta or pulmonary artery