Cardiology Flashcards
Foetal circulation Patent ductus arterioles Atrioventricular septal defect Coarctation of the aorta Pulmonary valve stenosis
Which vessel does oxygenated blood travel through to the baby?
Umbilical vein.
Which are the only 2 veins in the body to carry oxygenated blood?
- Pulmonary veins
2. Umbilical vein
How does the umbilical vein enter the foetal heart?
Via the ductus venosus in the liver.
What enters the right atrium of the foetus?
Deoxygenated blood from the SVC.
Mixed blood from the IVC (oxygenated from the umbilical vein and deoxygenated from the rest of the body)>
what happens once blood is in the right atrium of the foetus?
Most of the blood goes through the foramen oval into the left atrium.
Some of the blood goes into the right ventricle and into the pulmonary arteries.
Why does the right side of the heart have a higher pressure than the left side in the foetus?
Because there is vasoconstriction in the lungs due to them not needing a lot of oxygen.
This creates a back pressure in the pulmonary artery and back into the right side of the heart.
What happens to the blood that goes from the right atrium into the right ventricle?
It goes through the pulmonary artery (but not much blood is needed in the lungs) so most is passed via the ductus arteriosus into the aorta.
What happens to the blood that goes into the left atrium?
It goes into the left ventricle then into the aorta to supply the rest of the body.
Where does the deoxygenated blood go to drop off carbon dioxide?
There is 2 umbilical arteries which arise from the internal iliac arteries which take deoxygenated blood back to the placenta.
what keeps the ductus arteriosus open in utero?
The placenta produces prostaglandins.
How does the left side of the heart reach a higher pressure than the right side after birth?
Air rushes into the lungs and causes vasodilation - this reduces the pressure going back into the pulmonary arteries and right side of the heart.
how does the foramen oval close after birth?
Because there is a one way valve created by cardiac tissue which flows from right to left but once the left side of the heart is higher in pressure, the blood can’t flow from left to right.
what do the different structures become after birth?
Ductus venosus - ligamentum venosus
Umbilical artery - superior vesicle arteries (supplying bladder)
Umbilical vein - round ligament of the liver
Ductus arteriosus - ligamentum arteriosum
Foramen ovale - fossa ovalis
how does the ductus arteriosus become the ligamentum arteriosum?
the oxygen + reduction in prostaglandins from the placenta - cause the vessel to constrict.
When should the ductus arteriosus stop working?
within the first 1-3days of life.
when should the ductus arteriosus close?
Within 2-3 weeks after birth.
What are causes of patent ductus arteriosus (PDA)?
preterm baby
maternal infection (rubella)
Genetic
What are signs of a PDA?
dyspnoea poor feeding poor weight gain LRTI Murmur (not always present) Collapsing pulse
what is the pathophysiology of a PDA?
the pressure in the aorta is higher than in the pulmonary artery - creating a right to left shunt.
Increased pressure in the pulmonary vessels causes pulmonary hypertension and right sided ventricular hypertrophy.
You also get left ventricular hypertrophy.
What is the typical murmur heart in a PDA?
1st heart sound is normal.
2nd heart sound - crescendo-decrescendo machinery sounding murmur.
Which test confirms a PDA?
echocardiogram
How is a PDA managed?
In term babies - high chance of closure within 1yr.
If persists after 1 yr: Prostaglandin inhibitors (ibuprofen or indomethacin) Fluid restriction Diuretics catheter or surgical procedure.
What is an atrial septal defect?
When there is a hole in the septum between the two atrium allowing blood to flow between them.
What type of shunt do you get in an atrial septal defect?
A left to right shunt:
increasing blood pressure on the right side of the heart causing right sided overload and right heart strain.
Causes RHF and pulmonary hypertension.
What is an example of an atrial septal defect?
A patent foramen ovale.
what are complications of an atrial septal defect?
stroke atrial fibrillation atrial flutter RHF pulmonary hypertension
How does atrial septal defect cause a stroke?
usually after a DVT the clot will go through the right side of the heart and cause a PE.
If it gets from the right to the left side of the heart it can go up into the brain causing a stroke.
What type of murmur is present in an atrial septal defect?
Mid systolic crescendo-decrescendo murmur.
Heart loudest at the upper left sternal border.
What is the management for atrial septal defects?
small and asymptomatic - watch and wait.
surgery - transvenous catheter closure via the femoral vein or open heart surgery.
Anticoagulants - aspirin, warfarin, NOACs.
What is a ventricular septal defect?
A congenital hole in the septum between the two ventricles.
What conditions often cause ventricular septal defects?
downs syndrome
Turners syndrome
what is eidenmenger syndrome?
in an atrial or ventricular septal defect, the blood usually goes from the left to the right side of the heart.
BUT if the pressure in the right side gets too high then blood will go from the right to the left side - meaning it bypasses the lungs and is deoxygenated. Leading to cyanosis.
What infection is common with ventricular septal defect?
infective endocarditis.
What treatment is given for ventricular septal defect?
surgery - transvenous catheter or open heart surgery
prophylactic antibiotics during surgical procedures
what is coarctation of the aorta?
a narrowing of the aorta usually around the ductus arteriosus
What condition is associated with coarctation of the aorta?
Turners syndrome
what is the presentation of coarctation of the aorta?
weak femoral pulses High BP in upper limbs and low BP in lower limbs systolic murmur heard under left clavicle and scapula. tachypnoea poor feeding grey floppy baby Left ventricular heave underdeveloped left arm underdeveloped legs.
what is done for critical coarctation of the aorta?
prostaglandin E is given - to maintain a patent ductus arteriosus up until surgery to give some blood flow.
what syndromes are associated with pulmonary valve stenosis?
noonans syndrome
tetralogy of fallot
williams syndrome
How does a pulmonary valve stenosis present?
Raised JVP fatigue on exertion SOB dizziness fainting often asymptomatic ejection systolic murmur palpable thrill right ventricular heave
What is the prognosis for aortic valve stenosis?
often gets worse over time.
how are valve stenosis’ managed?
balloon valvuloplasty (venous catheter) or open surgery. Valve replacement.
what are the complications of aortic valve stenosis?
heart failure ventricular arrthymia bacterial endocarditis sudden death (often on exertion) left ventricular hypertrophy, dilatation and failure.
what are the signs of aortic valve stenosis?
Asymptomatic fatigue SOB dizziness fainting ejection systolic murmur palpable thrill slow rising pulse narrow pulse pressure.
What are the 4 problems in tetralogy of falot?
ventricular septal defect (VSD),
pulmonary stenosis,
a misplaced aorta
thickened right ventricular wall (right ventricular hypertrophy).
