Congenital Heart Defects

Question 1

Outline atrial septal defects (ASD)

Answer 1

Increased pulmonary blood flow
Right ventricular volume overload as left atrium higher pressure than right atrium
Pulmonary hypertension is rare
Eventual right heart failure

Question 2

Outline ventricular septal defect

Answer 2

Left to right shunt 
Most commonly a defect in membranous portion of interventricular septum 
Left ventricle volume overload 
Pulmonary venous congestion
Eventual pulmonary hypertension

Question 3

In what condition specifically are atrio-ventricular septal defects common in

Answer 3

Down syndrome

Question 4

What is congenital cyanotic heart defect

Answer 4

Deoxygenated blood bypassing the lungs and entering the left side of circulation
Right to left shunt requires a hole and distal obstruction

Question 5

What is Tetralogy of Fallot

Answer 5

Pulmonary stenosis - pulmonary pushed away into corner during development
Ventricular septal defect
Right ventricular outflow tract obstruction leading to right ventricular hypertrophy due to pulmonary stenosis
Overriding aorta - straddling two ventricles
Conotruncal septum formation defective
Importance of neural crest cells

Question 6

What is hypoplastic left heart

Answer 6

Left ventricle is underdeveloped
Not enough blood in chamber so atrophy of left ventricle muscle
Drugs can be given to newborns to keep the duct open to allow aortic reconstruction

Question 7

What is transposition of the great arteries

Answer 7

Not viable unless the two circuit communicate
Eg. Via atrial, ventricular or ducts shunts
Aorta arises from right ventricle
Pulmonary trunk arises from left ventricle
Leads to cyanosis
Cut aorta and pulmonary arteries and swap them over
Bidirectional shunting
Not genetic - failure of arteries and veins to rotate in embryo

Question 8

Describe tricuspid atresia

Answer 8

Lack of development of tricuspid valve
No right ventricular inlet
Right to left atrial shunt of entire venous system
Blood flow to lungs via ventricular septum defect
Blood has to flow through left ventricle and then left atrium to lungs

Question 9

Describe pulmonary atresia

Answer 9

Lack of development of pulmonary valve
No right ventricle outlet
Right to left atrial shunt of entire venous return
Blood flow to lungs via PDA

Question 10

Explain the significance of a patent ductus arteriosus

Answer 10

Patent ductus arteriosus - persistent communication between descending aorta and pulmonary artery
Ductus arteriosus shunts blood from pulmonary artery to aorta, and should close in the first breathe of the fetus as pressure in pulmonary drops
Failure to close leads to PDA (blood flow from aorta to pulmonary artery)

Question 11

Describe the effects of coarctation of the aorta

Answer 11

Coarctation is the narrowing in the aortic lumen
Increases the afterload of left ventricle and can lead to left ventricle hypertrophy
Vessels to the head and upper limbs usually emerge proximal to the coarctation, the blood supply to these regions is not compromised
Blood flow to the rest of the body is reduced