Session 3

Question 0

What is a patent foramen ovale?

Answer 0

Higher pressure in LA causes functional closure of flap valve. May be the route by which a venous embolus reaches the systemic circulation if pressure on right side of the heart increases even transiently.

Question 1

What is an atrial septal defect?

Answer 1

Opening in the septum between two atria which persists following birth.

Question 2

What is a ventricular septal defect?

Answer 2

A defect of the ventricular septum. Abnormal opening in the interventricular septum.

Question 3

Where does the most common ventricular septal defect occur?

Answer 3

In the membranous portion of the septum. LV pressure greater than RV pressure therefore blood flows from left to right.

Question 4

What should happen to the ductus arteriosus after birth?

What happens if this fails?

Answer 4

Should close shortly after birth as pressure in the RA drops following perfusion of the lungs.
Failure to close leads to patent ductus arteriosus. Blood flow through a PDA will be from aorta to PA after birth (high to low pressure)

Question 5

What can chronic left to right shunting result in?

Answer 5

Vascular remodelling of the pulmonary circulation and increase in pulmonary resistance. If resistance of pulmonary circulation increases beyond that of the systemic circulation the shunt will reverse direction as pressures on RHS of heart increases. (Eisenmenger syndrome)

Question 6

What is the coarctation of the aorta?

Answer 6

Narrowing of aortic lumen in the region of the ligamentum arteriosum. Increased afterload on the LV causes LV hypertrophy. As vessels to head and upper limbs are usually proximal to coarctation, the blood supply to these regions is not compromised. Blood flow to rest of the body is compromised.

Question 7

What is tetralogy of fallot?

Answer 7

Group of 4 lesions occurring together as the result of a single developmental defect which places the outflow portion of interventricular septum too far in the anterior and cephalad directions

Question 8

What are the four anomalies that occur in tetralogy of fallot?

Answer 8

Ventricular septal defect, overriding aorta, pulmonary stenosis and right ventricular hypertrophy.

Question 9

What is pulmonary stenosis?

Answer 9

Persistence of foetal RV hypertrophy because the RV has to operate at a higher pressure to pump blood through the pulmonary arteries. Increased pressure on RHS of the heart allows a right to left shunt and mixing of oxygenated and deoxygenated blood in the systemic circulation.

Question 10

What is an overriding aorta?

Answer 10

The aorta is positioned directly over a ventricular septal defect, instead of over the left ventricle.

Question 11

What is tricuspid atresia?

Answer 11

Lack of development of the tricuspid valve, leaving no inlet to the RV. Must be a complete right to left shunt of all the blood returning to the RA and a VSD or PDA to allow blood flow to the lungs

Question 12

What is transposition of the great arteries?

Answer 12

Two unconnected parallel circulations instead of two circulation in series. RV is connected to aorta and LV is connected to pulmonary trunk.
Not compatible after birth unless a shunt exists to allow the two circulations to communicate.

Question 13

What is a hypoplastic left heart?

Answer 13

LV and ascending aorta fail to develop properly. PFO or ASD ar also present and blood supply to the systemic circulation is via a PDA.

Question 14

What is the aetiology of congenital heart diseases?

Answer 14

Genetic e.g. downs syndrome,
Environmental e.g. teratogenicity from drugs, alcohol etc
Maternal infections e.g. rubella, toxoplasmosis etc

Question 15

What is the pathophysiology of the heart ?

Answer 15

RV pumps deoxygenated blood to the lungs. Pulmonary circulation has low resistance. LV pumps oxygenated blood at systemic blood pressure through aorta. Each ventricle is morphologically adapted for its task.

Question 16

Why is a left to right shunt damaging?

Answer 16

Increased blood flow to lungs is not so damaging, its the increased pressure of the PA and/or PV that is damaging

Question 17

What are the consequences of ASD?

Answer 17

Increased pulmonary blood flow, RV volume overload, pulmonary hypertension is rare –> eventual heart failure.
Usually asymptomatic, late onset arrhythmia and RH failure.

Question 18

What are the possible outcomes of VSD?

Answer 18

Left to right shunt created. LV volume overload, PV congestion, eventual pulmonary hypertension.
Present in infancy with LH failure. Can lead to in operable pulmonary hypertension if untreated.

Question 19

What are the consequences of tricuspid atresia?

Answer 19

No RV inlet, right to left shunt of entire venous return, blood flow to lungs via VSD (or PDA)

Question 20

What are the consequences of hypoplastic left heart?

Answer 20

LV underdeveloped, ascending aorta very small, RV supports systemic circulation, obligatory R–>L shunt.

Question 21

What is the typical presentation of coarctation?

Answer 21

Neonatal - associated with PDA, right to left shunt

Adult - complicated by renal hypertension, LV hypertrophy, often associated aortic valve stenosis.

Question 22

How does tetralogy of fallot usually present?

Answer 22

Presents in infancy or early childhood with cyanotic spells.