3) Congenital Defects Flashcards
Describe the effects of a left to right shunt
- via hole
- oxygenated blood from left mixes with deoxy in right
- blood returns to the lungs (not so damaging)
- increased pulmonary artery/venous pressure can be damaging
Name some causes of congenital heart defects
- Downs syndrome
- Turners syndrome
- Marfans syndrome
- tetragens
- drugs
- alcohol
- infection (Rubella, toxoplasminosis)
Describe a right to left shunt
- needs hole AND obstruction to pulmonary arteries
- deoxy bypasses lungs and mixes with oxy
- damaging to circulation
- cyanotic
What are the main shunts used by the developing foetus, hence those most vulnerable to defects after birth?
- Patent foreman ovale
- Patent ductus arterious
- interventricular septal defect
Describe an atrial septal defect (ASD)
- Opening between atrial septum (patent FO, ostium secundum hole or ostium primum hole)
- continued shunting of blood after birth
- LA pressure > RA so left to right shunt -asymptomatic
- can cause R-sided hypertrophy (can lead to right to lead shunt)
- late onset arrhythmia
- ^ pulmonary flow (not hypertension), RV overload and so eventual R-sided heart failure.
- can be route for a paradoxical embolism and entering circulation
Describe a VSD and it’s effects
-Opening in interventricular septum (often membranous portion)
-LV pressure > RV so left to right shunt
-can lead to LV overload due to increased pulmonary venous return
-pulmonary venous congestion
-eventual pulmonary hypertension
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Describe how a chronic patent ductus arterious can cause problems
- Shunt between PT and aorta
- aortic pressure > PT
- oxy mixes with deoxy in PT increasing volume
- CONSTANT MURMUR (aortic P always exceeds PT)
- chronic PDA will lead to pulmonary remodelling to reduce resistance to an extent
- too much resistance will cause back flow, then PT P > aortic
- deoxy enters systemic circulation (Eisenmenger syndrome)
- becomes CYANOTIC
What is coarctation of the aorta and what are its effect?
Narrowing of the aortic lumen (usually just before ligamentum arteriousum)
- larger back flow into LV
- LV hypertrophy
- BCT, LCC and LSA are not compromised as they branch proximal to the coarctation
- descending aorta receives reduced flow
- femoral (hypoT)-carotid (hyperT) pulse delay
What group of 4 lesions are known as tetralogy of fallot? And which of these unsure a right to left shunt?
VSD
Overriding aorta
Pulmonary stenosis
RV hypertrophy
What are the effects of T O F?
- right to left shunt
- cyanotic spells during stress/exercise
What is a pulmonary atresia?
- lack of development of the tricuspid valve
- no inlet to RV from RA
- need for right to left shunt (e.g ASD/PFO and VSD/PDA) to allow flow to lungs
What is the effect of transposition of the great arteries?
- 2 unconnected parallel circuits instead of 2 in series
- RV connected to aorta and LV to PT
- NOT COMPATIBLE WITH LIFE
- shunt needed immediately after birth until surgical correction (usually PDA or ASD)
What fails to develop in a hypo plastic left heart and how is flow to systemic circulation ensured?
LV, ascending aorta and mitral valve
-PFO or ASD WITH PDA
(Not compatible with life until surgical intervention)
