Cardiology Flashcards
Name three shunts facilitating transfer of waste (Co2, lactate) and nutrients (oxygen etc.) in the foetal circulation?
- Ductus venosus
- Foramen ovale
- Ductus arteriosus
What does the ductus venosus facilitate?
Blood to bypass the liver:
Umbilical vein –> IVC
What does the foramen ovale facilitate?
Blood to bypass the RV and pulmonary circulation
Right –> Left atrium
What does the ductus arteriosus facilitate?
Blood to bypass the pulmonary circulation
Pulmonary artery –> aorta
What does the ductus venosus become at birth?
Ligamentum venosum
What does the ductus arteriosus become at birth?
Ligamentum arteriosum
How does the ductus arteriosus become X at birth?
Becomes ligamentum arteriosum by increased blood oxygenation causing drop of circulating prostaglandins
What does the foramen ovale become at birth?
Fossa ovalis
How does the foramen ovale become the fossa ovalis at birth?
- 1st breath expands alveoli
- Decreases PVR
- Causes fall in RAP
- LAP > RAP
- Atrial septum squashed
- Foramen ovale forced shut
What is a patent ductus arteriosus?
Failure of ductus arteriosus to close (normally does so in 1st 2-3 weeks of life)
Patent ductus arteriosus pathophysiological process (and which direction the shunt is):
- Aorta Pa > pulmonary vessels Pa
- Left to right shunt (blood flow from aorta to pulmonary artery)
- Pulmonary hypertension
- RS heart strain as contract against greater resistance
- RVH
- LVH
Clinical presentation of baby with patent ductus arteriosus?
Note: some patients ASx until adulthood when they present in HF
SOB, poor WG and feeding, lower RTI
What murmur is heard in patent ductus arteriosus?
Normal 1st heart sound with continuous crescendo-decrescendo “machinery” murmur :. 2nd heart sound hard to hear.
How do you diagnose patent ductus arteriosus?
Echocardiogram
Assess effect on heart and L –> R shunt
Management for patent ductus arteriosus?
Monitor until 1 year old, hoping spontaneous closure
Trans-catheter or surgical closure
What is an atrial septal defect?
Defect in septum between two atria
Simple pathophysiology of atrial septal defects?
Septum primum and septum secundum should fuse with endocardial cushion to separate atria, but do not which is ASD
Pathophysiology of atrial septal defects? Think about the process (and which direction the shunt is)
- Septum primum and septum secundum do not fuse with endocardial cushion to separate atria
- LAP > RAP
- Left to right shunt
- Blood continues to flow to pulmonary vessels and lungs for oxygenation
- Yet leads to RHS overload and strain
–> 6. PH and RSHF
What can atrial septal defects result in as a secondary complication (name of the syndrome and what is occurring)?
Eisenmenger syndrome - shunt reversal to be right to left and bypassing the lungs
Why might a patient with an atrial septal defect suffer a stroke? (previously ASx and undetected)
- Clot to the RHS of the heart
- Then goes to the lungs becoming a pulmonary embolus
- Back to heart then through the right to the left atrium across the septal defect
- Clot to RV, aorta then brain
- STROKE
Complications of atrial septal defect?
Stroke, Eisenmenger syndrome (reversal of left to right shunt to become right to left), PH, RSHF, AF
What is the murmur associated with atrial septal defect?
Mid-systolic, crescendo-decrescendo murmur at upper left sternal border with fixed split-second heart sound.
Clinical presentation of atrial septal defect?
Infant and adult separately
Infant: SOB, difficulty feeding, poor WG, lower RTI
Adult: Dyspnoea, HF, stroke
Management of atrial septal defect? Paeds and adults
Paeds: Transvenous catheter closure - correction, or open-heart surgery
Adults: Anticoagulants (aspirin, warfarin, NOACs).
Why does Eisenmenger Syndrome occur for ASD?
Reversal of left to right shunt to be R to L, due to pulmonary pressure being greater than the systemic pressure.
Patient cyanotic
What are the three classifications of ASD?
Ostium secondum
Patent foramen ovale (though not strictly a ASD)
Ostium primum
Pathophysiology of ventricular septal defect (what does it lead to)?
- Hole between the ventricles
- Left to right blood flow due to increased LV pressure
- Acyanotic as blood still oxygenated
- Long-term pressure rise; right>left so right to left shunt occurs (Eisenmenger syndrome)
Clinical presentation of ventricular septal defect?
Failure to thrive
Poor feed
Dysnpnoea
ASx; often pick up later when progress to PH, RSHF, RS overload.
What are the long-term complications of ventricular septal defect?
RHF, right side overload, PH.
What is the murmur observed in ventricular septal defect?
Pan-systolic at left lower sternal border in 3rd/4th ICS.
Treatment for VSD?
Watchful wait - spont. closure
Surgical - tranvenous cath., open heart surgery
Abx Px due to high IE risk
What is coarctation of the aorta?
Narrowing of aortic arch around the ductus arteriosus
What infection are ventricular septal defect babies at risk of?
Infective endocarditis
Pathophysiology of coarctation of the aorta?
- Reduces pressure of blood flowing to arteries distal to narrowing
- Increases pressure of blood in area proximal to narrowing e.g. heart and aorta three branches