Congenital Heart disease Flashcards
Why does a baby have shunts?
Blood doesnt pass through the pulmonary circulation as lungs not functional with gas exchange in mother
What are the three foetal shunts?
Ductus venosus
Foramen ovale
Ductus arteriosis
Where is the ductus venosus?
Umbilical vein to IVC
What does ductus venosus allow?
Blood to bypass RV and pulmonary circulation
Where is the foramen ovale? What does it allow to bypass?
RA and LA - allows bypass RV and pulmonary circulation
Where is the ductus arteriosis and what does it allow to bypass?
Pulmonary artery with aorta, bypasses pulmonary circulation
How does the foramen ovale ckose after birth?
First breath expands alveoli decreasing pulmonary vascular resistance -> decreased pressure in RA, which means LA has higher pressure, squashing atrial septum and closes foramen ovale
What does the foramen ovale become a few weeks after birth>
Foramen ovalis - weeks (when structurally shut)
What keeps the ductus arteriosus open?
Prostaglandins
What causes the ductus arteriosis to close?
Increased blood oxygenation -> drop in circulating prostaglandins, causing closure of ductus arteriosus
What does the ductus arteriosus become?
Ligamentum arteriosum
Why does the ductus venossu shut immediately after birth?
Umbilical cord clamped, no flow in umbilical veins
Structura;y closese in dyas -> ligamentum venosum
What to remember about presentation of PDA?
Pink and stable - breathless
When does the ductus arteriosus stop functioning vs structurally close?
Stop functioning 2-3 days after birth
Completely closes 2-3 weeks
What causes PDA?
Unclear
Prematurity high risk
Maternal infections? eg rubella
When is PDA asymptomatic?
Small - no functional problems, spontaneous closure
When do adults present with heart failure after PDA?
Undiagnosed PDA because asymptomatic
What direction does the blood flow through the PDA?
Left to right shunt
Aorta to pulmonary vessels
How does PDA lead to HF?
Increased pressure in pulmonary vessels as blood continues passing from the aorta into them
Pulmonary hypertensin
Rs heart strain
-> RV hypertrophy
Increased afterload -> LV hypertrophy
Symptoms of PDA and ASD in childhood
SOB
difficulty feed
Poor weight gain
LRTIs
Murmur heard with significatn PDAs
Continuous cresceno-decrescendo machinery murmur (may continue with second heart sound)
How to diagnose PDA?
ECHO cardiogram
Size and charcteristics of shunt
How long are patients with PDA monitored for?
Until 1 year of age
When is surgery considered for PDA and why?
sYMPTOMATIC
Evicdence of HF as direct consequence of PDA
After one year as then highly unlikely to spontaneously close
What is an atrial septal defect?
Hole in septum between artria - mizing of blood between them
Where do defects a=occur in development to ause ASD?
Problems with septum primum and septum secundum or with them fusing together or with endocardial cushion
What hole should occur in the septum secundum?
Foramen ovale
Which direction does blood move in ASD?
L to R - increased pressure in L pushes
How cna RH failure be caused by ASD?
Increased flow to R -> overload and heart strain
-> pulm hypertension and RH failure
What can pulmonary hypertension lead to long term?
Eisenmonger syndrome
What is eisenmonger syndrome?
Pulmonary pressure > systemic
Shunt reverses - R to L across ASD
Blood bypasses lungs
Patient becomes cyantoics
What could you suspect in a patient with long term ASD where they become cyanotic?
Eisenmonger syndrome - reversla in direction of ASD shunt
Most to least common ASDs
Ostium secondum (primum secundum fails to close)
Patent foramen ovale
Ostium primum -> Atrioventricular septal defect
Complications from ASD
Stroke in ctonext of VTE
Atrial fibrillation or flutter
Pulm hypertension and RSH failure
Eisenmonger syndrome
What is a DVT likely to cause in a patient with ASD?
Stroke
Why do patients with ASD have a stroke from a VTE rather than a PE?
Embolus from DVT -> RA -> LA across ASD
Clot -> LV -> aorta -> brain -> stroke
What is heard with an ASD?
Mid-systolic, crescendo-decrescendo murmur loudest at L sternal border with fized slit second heart sound
What is a fixed split S2?
Split does not change with inspriation or expiration (normally get normal split on inspiration)
Why is their a fixed split heard in ASD?
RV has more blood to empty due to shunt before pulmonary valve can close
How can ASDs present in al=dulthood?
Dyspnoea
Heart failure
Stroke
How can PDAs be treated surgically
Transcatheter
Surgical valve closure
How can ASDs be surgically fixed
Transvenous catheter closure via femoral vein
Open heart surgery
Management for ASD options
Watch and wait - small and asymtpomatic
Anticoagulatns - reduce risk clots in adults
Surgery
What colour do patients present with eisenmenger syndrome?
Blue, unstable
What underlying lesions can cause eisenmenger syndrome?
ASD
Ventricular septal defect
PDA
How long does eisenmenger syndrome take to develop large vs small shunts?
Large - 1-2 years
Small - Adulthood
When monitor for eisenmenger syndrome in pregnant women?
Develops more quickly in pregancy
history of hole in heart
ECHO
Close cardiologist monitoring
Main causes of death with eisenmengers
HF
Infection
VTE
haemorrhage
Main causes of death with eisenmengers
HF
Infection
VTE
haemorrhage
Mortality in eisenmengers
20 year reduced life expectancy
50% mortality in pregnancy
What shunts cause deoxygenation vs not
L to R shunt does NOT cause cyanosis 0 blood stull travels to lungs and is oxygenated
R to L shunt - blood is removed from pulmonary circultation, not enough gets oxygenated to provide for body -> cyanosis
Mechanism allowing chagning direction of shunt in eisenmengers?
Extra blood into R system causing pulmonary HPTN -> eventually succeeds systemic pressure, changes blood flow R to L
Allows deoxygenated blood back into the body circulation.