Cyanosis, Atrial And Ventricular Septal Defects, Coarctation Of The Aorta

Question 1

What is cyanotic heart disease and cyanosis?

Answer 1

Cyanotic heart disease refers to a group of different structural heart defects that are congenital, these result in low O2 as deoxygenated blood enters the systemic circulation.

Cyanosis has a bluish colour of the skin and mucous membranes resulting from deoxygenated blood +/- reduced blood flow

Question 2

What structural heart defects does cyanotic heart disease include?

Answer 2

• ventricular septal defects (VSD)
• atrial septal defect (ASD)
• coarctation of the aorta
• Hypoplastic left heart syndrome
• Tetralogy of Fallot
• Transposition of great vessels
• Ebstein anomaly - tricuspid valve sits lower than normal in RV and tricuspid valve leaflets are abnormally formed

Question 3

Symptoms of cyanotic heart disease

Answer 3

• blue lips, fingers and toes
• breathing problems
• tiredness
• sweating
• poor weight gain
• fainting and chest pain may occur

Question 4

Cyanotic HD can cause HF. What are the symptoms of heart failure in a baby?

Answer 4

• rapid and laboured breathing
• hypoxia
• enlarges +/- pulsation liver
• poor feeding
• failure to grow
• cardiomegaly on chest X-ray

Question 5

What is an atrial septal defect?

Answer 5

A congenital defect with a hole in the septum that divides the atria

Question 6

What can ASD lead to?

Answer 6

• results in decreased LV diastolic filling, increased pulmonary-systemic flow ratio through the defect and diminished systemic flow
• means oxygenated blood flows from LA to RA so there is a loss of oxygenated blood from the systemic circulation resulting in poor oxygenation of tissues - cyanosis

Question 7

ASD criteria

Answer 7

• voltage evidence of RVH
  
  • dominant R wave in V1 >7mm
  • dominant S wave V5-V6> 7mm
  • RV strain pattern with ST depression and T wave inversion in V1-V3, II, III and aVF
• slight RAD
  
  • negative in I
  • positive in II, III, avF
  • lead III has the tallest QRS
• incomplete RBBB/ or RBBB
• tall P wave (indicative of RAE)

Question 8

What is a ventricular septal defect?

Answer 8

• congenital hole in septum

Question 9

What can a VSD cause?

Answer 9

-left to right shunts where direction and magnitude of blood flow are determined by the size of the defect
-mixture of oxygen poor blood and oxygen rich blood from LV to RV causing reduced cardiac output and oxygen to body

Question 10

ECG changes with VSD

Answer 10

Extra blood supply to RV from LV causes increased lung flow causing:
- if VSD is small, ECG is normal
- LAE (wide, notched P wave)
- LVH ( deep S waves V1, tall R waves V5-V6)
Can result in pulmonary resistance increasing due to pulmonary hyper flow leading to;
-RVH
- RAD
- Dominant R wave in V1>7mm
- Dominant S wave V5/V6> 7mm
- RV strain pattern, ST depression/ T inversion V1-V3 and inferior leads

Question 11

How can the shunt change directions?

Answer 11

As pulmonary pressure increases, pulmonary HTN develops.
As pressure differences between systemic and pulmonary systems decreases, flow across shunt decreases (left to right shunt)
If pulmonary vascular resistance exceeds systemic resistance, the direction of shunt reverses and cyanosis develops

Question 12

What is coarctation if the aorta?

Answer 12

Congenital disease in which the aortic segment is constricted (narrowed). This is usually at the ligamentum arteriosum.

Question 13

What can coarctation of the aorta cause?

Answer 13

• Narrowing of vessel causes increased resistance to blood flow, which increases afterload of LV causing LVH
• Blood supplying head, arms, neck not affected, although can increase bp. However there is reduced bp in lower limbs due to reduced blood supply . This can cause weakness in lower limbs and a weak femoral pulse (radio-femoral delay) : a mismatch in timing of radial pulse and femoral pulse
• important to catch as infants cannot otherwise survive past neonatal period

Question 14

Treatment options for coarctation of aorta

Answer 14

• surgery to correct defect
• balloon angioplasty and stenting using cardiac catheterisation

Question 15

Hypoplastic left heart syndrome and treatment

Answer 15

• left side of heart (LA/LV/aorta) are small and underdeveloped and mitral valve is atretic (underdeveloped and failed to open)
• survival dependant on presence of ASD and PDA
• treatment involves connection superior VC and inferior VC directly to pulmonary arteries (Fontan)
• the main pulmonary artery is connected to the aorta and becomes a systemic vessel from a systemic RV

Question 16

Tetralogy of Fallot and treatment

Answer 16

• most common cause of cyanotic CHD
• includes a VSD, a narrow pulmonary valve, RVH and misplaced aortic valve ( (VSD), pulmonary stenosis, a misplaced aorta and a thickened right ventricular wall (right ventricular hypertrophy))
• the defects lead to oxygenated and deoxygenated blood mixing
• treatment involves patching VSD and either bypassing the narrowed pulmonary valve with a conduit or ballooning the valve

Question 17

Total anomalous pulmonary venous return

Answer 17

Pulmonary veins drain into SVC/IVC/coronary sinus. ASD is present. Treatment involves surgically connecting veins to LA

Question 18

Transposition of the great arteries and treatment

Answer 18

Great vessels are transposed so that aorta rises from RV and pulmonary valve arises from LV.
- a septal defect or PDA might be present for survival
- treatment involves surgically switching the vessels

Question 19

Patent foramen ovale (PFO)

Answer 19

• hole between LA and RA, existing in utero and closes shortly after birth
  -PFO fails to close after baby is born, so venous blood leaks from RA to LA and then to body
  -blood clots can form and causes strokes in brain
  treatment involves cardiac catheterisation, to permanently close the PFO, however this is not usually treated unless person has other heart problems, symptoms or have had a stroke