Congenital Heart Disease

Question 1

What are levocardia, mesocardia and dextrocardia?

Answer 1

• Levocardia – apex of heart points to the left (normal)
• Mesocardia – apex of heart points to the middle
• Dextrocardia – apex of heart points to the right

Question 2

What are situs solitus situs inversus and heterotaxy?

Answer 2

• Situs solitus – left atrium on left and right atrium on right (normal)
• Situs inversus – left atrium on the right and right atrium on the left
• Heterotaxy – two left or right atria (left/right isomerism)

Question 3

What are AV concordance, AV discordance and double inlet ventricle?

Answer 3

• AV concordance – LA connects to LV and RA connects to RV (normal)
• AV discordance – LA connects to RV and RA connects to LV
• Double inlet ventricle – both atria empty into one ventricle

Question 4

What are VA concordance, VA discordance and double outlet ventricle?

Answer 4

• VA concordance – arteries come off of correct ventricles
• VA discordance – arteries come off of wrong ventricles
• Double outlet ventricle – both arteries come off the same ventricle

Question 5

What are the morphological features of the RV?

Answer 5

• Trabeculated endocardium
• Insertion of chordae to IVS
• Moderator band

Question 6

What are the morphological features of the LV?

Answer 6

• Smooth endocardium
• Ellipsoid cavity

Question 7

What is a shunt?

Answer 7

• The mixing of red and blue blood

Question 8

What is the difference between cyanotic and acyanotic CHD?

Answer 8

• Cyanotic means blue blood is getting into the circulation and acyanotic means this isn’t happening

Question 9

What is the pathophysiology and complications of an ASD?

Answer 9

• Secundum most common
• Shunts right to left when in isolation
• Right heart volume loading
• Pulmonary flow murmur and split second heart sound
• May lead to RV failure, tricuspid regurgitation, pulmonary HTN, atrial arrhythmias and Eisenmenger syndrome (increased pressure in RV/RA eventually reverses shunt leading to a cyanotic leasion)

Question 10

What is the pathophysiology and management of coarctation of the aorta?

Answer 10

• Narrowing of the aorta
• Pressure proximal to coarctation is high and distal is low
• Tends to form after left subclavian artery in a ‘juxta-ductal’ position
• Pre-ductal can cause lower limb cyanosis
• Upper body HTN, Berry aneurysms, claudication and renal insufficiency may ensue
• Rib notching may present on CXR due to retrograde flow from high pressure anterior intercosal arteries to low pressure posterior
• Surgical repair (subclavian flap, end to end, jump graft)

Question 11

What is the pathophysiology of Tetralogy of Fallot?

Answer 11

• Ventricular septal defect
• Overriding aorta
• RVOT obstruction
• RV hypertrophy
• Can be repaired by BT shunt (one branch of subclavian or carotid artery is seperated and connected with the pulmonary artery) or complete repair (pulmonary artery and RV enlarged using a patch, muscular obstruction removed and VSD closed using a patch)

Question 12

What is the pathophysiology of transposition of the great arteries?

Answer 12

• Oxygenated blood from pulmonary veins is re-circulated to the lungs
• Deoxygenated blood from the body is recirculated to the body
• Maintained in-utero as oxygenation by maternal placenta
• After birth PFO and ductus arteriosus allow blood to pass through but close soon after birth
• Incompatible with life if not repaired

Question 13

What is the pathophysiology of Fontan circulation?

Answer 13

• Tricuspid valve hasn’t formed
• Need an ASD or PFO to allow blood to reach other atrium
• Also need a VSD to allow blood to get to lungs
• Lungs are exposed to systemic BP which causes pulmonary HTN
• Beyond conventonal repair
• Repair involves making one large ventricle and one large atrium. Blood from the lungs enters the right (now common) atrium, moves into the left (now common) ventricle and is pumped into the body, deoxygenated and goes back to the pulmonary artery and passively to the lungs