Congenital Heart Disease Flashcards
Describe morphology of the RA?
Contains the SA node
Broad appendage
Describe morphology of the LA?
Narrow, long appendage
Describe morphology of the RV?
Trabeculated endocardium
Insertion of the chordae to the IV septum
Thick moderator band muscle.
Describe morphology of the LV?
Smooth endocardium, ellipsoid cavity.
What is the most common atrial septal defect?
Secundum
How does a secundum ASD occur?
When foramen ovale fails to close leaving a hole between atria.
What happens to blood in a secundum ASD?
Blood can mix and normally shunts left to right.
How could you identify a secundum ASD on examination?
Pulmonary flow murmur
Fixed split second heart sound.
What other heart problems can a secundum ASD lead to?
- RV failure as RV receives blood from both atria and becomes dilated.
- Atrial arrhythmias such as AF.
- Tricuspid regurgitation.
What other non-heart problems can a secundum ASD cause?
- Pulmonary hypertension
- Eisenmenger Syndrome
- Stroke
How are secundum ASD’s treated?
Surgery via sternotomy or transcatheter approach from groin.
What is transposition of the great arteries?
Where they aorta and pulmonary artery switch.
Aorta is connected to the RV
Pulmonary artery now connected to the LV.
2 separate circulation systems exist.
Is transposition of the great arteries a cyanotic condition?
Yes - incompatible with life.
What is the M:F ratio for transposition of the great arteries?
4:1
What immediate treatment is given to babies with transposition of the great arteries? Why?
When born, the foramen ovale and ductus arteriosus close over the first hours of life. When this occurs in this condition, 2 seperate circulation systems are created and there is a seperate systemic and pulmonary circulation therefore the blood travelling round the body is deoxygenated.
We give prostaglandins to maintain these structures to allow mixing of blood so oxygenated blood can also get into the systemic circulation. This buys times.
Describe long term treatment options for transposition of the great arteries?
Atrial switch: Creates a baffle (tunnel) between atria so blood can mix
Arterial switch: Cut pulmonary artery and aorta above valves and switch them to resemble normal anatomy.
Discuss problems with surgery for transposition of the great arteries?
Atrial switch: Issue as RV isnt made to provide systemic circulation so it dilates. This can also stretch the tricuspid valve and cause regurgitation.
Stretched atria can also cause atrial arrrhythmias.
Arterial switch: Coronary arteries are attached to the pulmonary artery so need switched also. They can become disrupted or occluded by surgery causing cardiac perfusion problems.
What are the features of tetralogy of Fallot? list only.
- Ventricular septal defect.
- Overriding aorta.
- RVOT obstruction.
- RV hypertrophy.
What is the result of the features in a tetralogy of Fallot?
- VSD: mixing of blood down pressure gradient from left to right.
- Overriding aorta: Aorta pulled towards RV and sits above septum. Mixed blood goes up aorta causing cyanosis.
- RVOT obstruction: Due to no pulmonary valve or bulky muscle mass under the valve. Causes restricted blood flow to the pulmonary arteries.
- RV hypertrophy: Due to RV working harder.
What are the treatment options for tetralogy of Fallot?
BT shunt: use subclavian or carotid artery and plumb into the pulmonary artery to improve blood supply to the lungs. Can now use goretex tubes to do the same.
Patch: used to close septal defect.
Can cut away bulk affecting pulmonary valve.
As lung arteries are under-developed can enlargen (using patch???)
Highlight some post-surgical problems in tetralogy of fallot?
- Over time surgery tires. May leads to pulmonary regurgitation and RV dilatiation.
(combat this by valve replacement). - Arrhythmia as increased RV pressure causes increased RA pressure and RA dilates to cope. Dilation can be vunerable to tachycardiac arrhythmias.
- Pulmonary artery stenosis.
What is a univentricular heart?
Heart with only one ventricle.
Relies on shunt for mixing of blue and red blood.
Why does a univentricular heart occur?
Many reasons, most common is tricuspid atresia.
How is a univentricular heart treated?
Aim to make 2 ventricles, but irregular anatomy may not allow for this.
Can create Fontan circulation.
- IVC and SVC are plumbed directly into the pulmonary arteries.
What are the issues with Fontan circulation?
Without an RV to pump blue blood to pulmonary circulation, we rely on high systemic pressure to drive blood to pulmonary arteries.
This is a vunerable balance.
Any pressure changes could cause haemodynmic compromise, for example..
- arrhythmias
- dehydration
- PE
- blood loss
What drug are all patients with fontan circulation on?
Anti-coagulants.
How does a foetus receive oxygenated blood?
From the placenta.
What 2 important structures are present in foetal hearts?
Foramen ovale
Ductus arteriosus
Describe foeal circulation in relation to these structures?
Because the lungs are not fully formed, vascular resistance in the pulmonary arteries is high.
Therefore blood from IVC takes the path of least resistance and passes through the foramen ovale to the LA.
A small amount of blood goes through the RV to the pulmonary vein, but nearly all passes through the ductus arteriosus to the aorta.
When do the foramen ovale and ductus arteriosus regress?
When baby takes first breath, pressure changes in the heart and the lungs.
Over the next few hours these structures close.
What is co-arctation of the aorta?
Congenital narrowing of the aorta.
Where does co-arctation normally occur?
after the left subclavian artery in a juxta-ductal position.
What happens to the LV in co-arctation of the aorta?
LV has to pump harder to force blood through narrowing.
This causes LV hypertrophy.
If not corrected = LV failure
Why do co-lateral vessels form in co-arctation of the aorta?
As blood tries to take the path of least resistance so tries to find alternative ways to by pass the narrowing.
If severe co-arctation is severe, what signs would you see?
- cold feet
- claudication
- abdominal angina
- upper body hypertension: BP in arms is greater than the legs
- radio-femoral pulse delay
- headaches
- berry aneurysms
- renal insufficency.
What signs on x-ray would indicated co-arctation?
Rib notching due to retrograde flow from anterior intercostal arteries to low pressure posterior arteries.
What would you hear on auscultation of a co-arctation?
Narrowing cause turbulent flow which can be heard as a continuous murmur on the front and back of chest.
What treatments can be offered for co-arctation?
Surgical
- Subclavian artery flap
- Resection of narrowing and anastamose ends (this is used now!)
Transcatheter
- Use balloon via femoral artery to dilate narrowing.
