Lecture 2.2: Cardiovascular Pathologies and Congenital Defects

Question 1

What are some Acyanotic Heart Defects? (5)

Answer 1

• Atrial Septal Defect (ASD)
• Patent Foramen Ovale (PFO)
• Ventricular Septal Defect (VSD)
• Coarctation of the Aorta
• Patent Ductus Arteriosus (PDA)

Question 2

Acyanotic Defects: Atrial Septal Defect (ASD)

Answer 2

• Opening in septum between atria which persists postnatally
• Left atrial pressure > right atrial pressure
• Therefore there is no deoxygenated blood being pumped systemically

Question 3

What are some complications of Atrial Septal Defect (ASD)?

Answer 3

• Left-right shunting can be problematic if untreated
• The extent of the problems is dependent on the degree of shunting
• Chronic left-right shunting can lead to vascular remodelling of the pulmonary
circulation and an increase in pulmonary resistance
• If the resistance of pulmonary circulation exceeds that of systemic circulation, t
the shunt will reverse direction (Eisenmonger syndrome)

Question 4

Acyanotic Defects: Patent Foramen Ovale (PFO)

Answer 4

• Present in ~20% of the population
• Patent foramen ovale is a hole between the left and right atria of the heart
• This hole exists in everyone before birth
• But most often closes shortly after being born
• Clinically silent usually, as higher left atrial pressure maintains functional flap
valve closure

Question 5

What are some complications of Patent Foramen Ovale (PFO)?

Answer 5

PFO can be route for venous embolism reaching systemic circulation if right atrial pressure exceeds left even transiently

Question 6

Acyanotic Defects: Ventricular Septal Defect (VSD)

Answer 6

• Abnormal opening in inter-ventricular septum
• As left ventricular pressure exceeds right, there is a left-right shunt and no
deoxygenated blood is circulated systemically

Question 7

Acyanotic Defects: Patent Ductus Arteriosus (PDA)

Answer 7

• Ductus arteriosus exists in foetus to shunt blood from the pulmonary artery into
the aorta
• Vessel should close shortly after birth as pressure in pulmonary artery drops
upon perfusion of lungs
• Failure to close leads to PDA which results in flow from aorta to pulmonary
artery (high to low pressure)

Question 8

Acyanotic Defects: Coarctation of the Aorta

Answer 8

• Narrowing of aortic lumen in the region of ligamentum arteriosum (former
ductus arteriosus)
• Increases after-load on left ventricle which can lead to left ventricular
hypertrophy
• Vessels to head and upper limbs usually proximal to lesion hence blood supply
there not compromised
• Blood to rest of body is reduced

Question 9

Complications and Signs of Coarctation of Aorta

Answer 9

• Extent of symptoms depends on severity of coarctation
• If very severe, infant may present with symptoms of heart failure shortly after
birth
• In mild cases defect may be detected in adult life
• Femoral pulses will be weak and delayed with upper body hypertension

Question 10

What are some Cyanotic Heart Defects? (4)

Answer 10

• Tetralogy of Fallot
• Tricuspid Atresia
• Transposition of the Great Arteries
• Hypoplastic Left Heart

Question 11

Cyanotic Defects: Tetralogy of Fallot

Answer 11

• Group of 4 lesions occurring together as a result of a single developmental
defect
• The four anomalies are VSD, overriding aorta, and a variable degree of
pulmonary stenosis and right ventricular hypertrophy

Question 12

Complications of Tetralogy of Fallot

Answer 12

• Pulmonary stenosis causes persistence of foetal right ventricular hypertrophy
• Increased right ventricular pressure along with VSD and overriding aorta allow
right to left shunt
• Mixture of oxygenated with deoxygenated blood within systemic circulation
leads to cyanosis
• Magnitude of shunt and level of severity dependent on degree of pulmonary
stenosis

Question 13

Cyanotic Defects: Transposition of the Great Arteries

Answer 13

• Two unconnected parallel circulations instead of two circulations in series
• Right ventricle is connected to the aorta and the left ventricle to the pulmonary
trunk
• Condition is not compatible with life after birth unless a shunt exists to allow
the two circulations to communicate
• A shunt must be maintained or created immediately following birth to sustain
life until surgical correction can be made
• The ductus arteriosus can be maintained patent and/or an atrial septal defect
formed

Question 14

Cyanotic Defects: Hypoplastic Left Heart

Answer 14

• Left ventricle and ascending aorta fail to develop properly
• A PFO or ASD are also present and blood supply to
the systemic circulation is via a PatDuctusArterio
• Without surgical correction this condition would be lethal

Question 15

Staged Reconstructive Repair of HPHS

Answer 15

• Pioneered in the 1980s
• Comprises of three separate procedures taking place within 1st 4yrs of life
• Aim is to make the right ventricle perform the traditional job of the left
supplying the body with oxygenated blood
• While the passive systemic venous pressure performs the traditional job of the
right, passing deoxygenated blood to the lungs

Question 16

Staged Reconstructive Repair of HPHS: Stage 1 The Norwood Procedure

Answer 16

• Typically done within first week of life
• ASD is made bigger
• Encouraging further mixing of oxygenated blood from left atrium into right
atrium
• New aorta is reconstructed from itself alongside the pulmonary artery
• Graft provides blood flow to lungs either from subclavian artery or direct from
right ventricle

Question 17

Staged Reconstructive Repair of HPHS: Stage 2 Glenn Repair

Answer 17

• Typically done at 4-6 months of age
• Required to reduce load on right ventricle
• Superior vena cava is disconnected from right atrium and plugged directly into
pulmonary artery
• Venous blood from upper body now bypasses heart and flows directly into
lungs
• Original shunt made during step 1 connecting arterial and venous blood is
removed

Question 18

Staged Reconstructive Repair of HPHS: Stage 3 Fontan Operation

Answer 18

• Typically done at 18-36 months of age
• IVC disconnected from heart and routed directly to pulmonary artery
• Blood from lower body now bypasses heart and goes straight to lungs

Question 19

Cyanotic Defects: Tricuspid Atresia

Answer 19

A birth defect of the heart where the valve that controls blood flow from the right upper chamber of the heart to the right lower chamber of the heart doesn’t form at all

Question 20

What are some Non-Congenital Cardiovascular Pathologies (3)

Answer 20

• Valvular Heart Disease
• Dissection of the Aorta
• Myocardial Infarction

Question 21

What is Dissection of the Aorta?

Answer 21

• Damage to tunica intima leading to a tear in which wall of aorta splits
longitudinally
• Creates false channel (false lumen) into which blood is forced under high.
pressure
• Rare but serious medical emergency
• Clinically manifests as severe sharp ‘tearing’ chest pain

Question 22

Complications of Dissection of the Aorta (4)

Answer 22

• Aortic Regurgitation
• Cardiac Tamponade
• End-Organ Ischaemia
• MI

Question 23

What is Myocardial Infarction?

Answer 23

• Cardiac death resulting in ischaemia in cardiac myocytes as a result of
atherosclerosis in the coronary arteries
• Ischaemia triggers visceral pain endings in the myocardium

Question 24

Why is MI pain often felt in the arms?

Answer 24

• These visceral pain fibres run through the sympathetic trunk into the spinal
cord from T1-T5, especially on the left side
• Pain is referred to the upper limb due to common ganglia and posterior roots
as sensory nerves deriving from the arm

Question 25

What is Valvular Heart Disease?

Answer 25

• When any valve in the heart has damage or is diseased

Question 26

Types of Valvular Heart Disease?