6. Structural Heart Defects Flashcards
What are structural heart defects?
Common Congenital Cardiac Malformations
Name a congenital heart defect that is cyanotic.
Tetralogy of Fallot.
Right to left shunt.
Name 3 congenital heart defects that are not cyanotic.
- VSD.
- ASD.
- PDA.
Left to right shunt! This is okay but a bit insufficient and there is a risk of Eisenmengers syndrome.
Explain the pathophysiology of Tetralogy of Fallot.
The stenosis of the RV outflow leads to the RV being at higher pressure than the left.
Therefore: ‘blue blood’ passes from the RV to the LV.
Aetiology of Tetralogy of Fallot?
Abnormalities in separation of truncus arteriosus into the aorta and pulmonary arteries early in gestation
What are the 4 main features of Tetralogy of Fallot?
1 - Ventricular septal defect (VSD)
2 - Pulmonary stenosis
3 - Right ventricle hypertrophy (RVH)
4 - Aorta overriding the VSD (over-riding aorta)
Think PROV:
Pulmonary stenosis
RVH
Overriding aorta
Ventricular septal defect
Describe the presentation of Tetralogy of Fallot.
Acyanotic at birth; gradually become cyanotic.
Tet spells.
Fallow (hypoxic) spells - go blue, restless.
Inconsolable crying.
Toddlers may squat.
Give 2 clinical signs of Tetralogy of Fallot.
- Left pulse weaker
- Clubbing
What is the characteristic feature of a CXR in Tetralogy of Fallot?
Boot shaped heart
Management of Tetralogy of Fallot.
For Tet spells:
- Long term beta-blockers
- Oxygen (100%)
- Knee-chest position + squatting
For acute episodes:
- Rapid intervention with morphine
Surgery at less than 12 months.
Would a baby born with Tetralogy of Fallot be cyanotic?
YES! There is a greater pressure in the RV than the LV and so blood is shunted into the LV -> CYANOSIS!
What is Ventricular Septal Defect (VSD)?
An abnormal connection between the two ventricles.
What are the 2 causes of VSD?
- Congenital
- Acquired post-MI
Explain the pathophysiology of VSD.
- High pressure LV.
- Low pressure RV.
- Blood flows from high pressure chamber to low pressure chamber.
- Therefore: NOT blue.
- Increased blood flow through the lungs.
Would a baby born with VSD be cyanotic?
No. There is a higher pressure in the LV than the RV and so blood is shunted from the left to right meaning there is an increased amount of blood going to the lungs; not cyanotic.
What is the difference between large VSD and small VSD?
Large: Very high pulmonary blood flow in infancy; requires fixing in infancy
Small: Small increase in pulmonary blood flow only; no intervention needed
How might a VSD present?
Severe heart failure in infancy.
OR - asymptomatic, detected later in life
Give 4 clinical signs of a large VSD.
- High pulmonary blood flow.
- Breathless, poor feeding, failure to thrive.
- Increased respiratory rate.
- Tachycardia.
What is seen on a CXR of someone with VSD (small and large)?
Small VSD - normal sized heart ± enlarged pulmonary blood vessels.
Large VSD - cardiomegaly (big heart), large pulmonary arteries, marked enlargement of pulmonary vessels.
Does a small VSD produce louder or quieter murmurs than a large VSD?
Louder
(loud pansystolic murmur)
What murmur is heard in VSD?
Harsh pansystolic murmur at left sternal edge, with systolic thrill
What can be heard for a VSD?
- Pansystolic murmur - loudest at the left lower sternal angle)
- RV heave / loud P2 (sound produced by the closure of the pulmonic valve)
Give 2 complications of a VSD.
Aortic regurgitation.
Infundibular stenosis.
IE.
Pulmonary hypertension.
Eisenmenger’s complex.
Management of a VSD.
Medical support until spontaneous closure.
OR - surgical patch repair or device closure.
What syndrome might VSD lead on to?
Eisenmengers syndrome.