Cardiology Flashcards
Where is the obstruction in the vast majority of aortic coarctation cases?
Distal to L subclavian artery, often at location of ductus arteriosus (aortic isthmus)
Is aortic coarctation more common in boys or girls? Syndromic caveat?
Boys
But seen in Turner syndrome
What lab finding might be apparent in aortic coarctation and why?
Raised lactate as hypoperfuse lower limbs
How does aortic coarctation present on exam?
Disparity in pulse volume in arms vs legs, also BP differences
Absent femorals
Systolic murmur below left clavicle is typical but variable
When might a coarctation present and why? What implications does this have for management?
Day 2 plus of life after a PDA has closed - it is duct dependent
Can give prostins to keep duct open and prevent CV collapse
What is milrinone and what is it used for?
Phosphodiesterase 3 inhibitor which increases heart contractility and reduces pulmonary vascular resistance, also decreases afterload via peripheral vasodilation
Used in heart failure and LCOS as well as post cardiac surgery to maintain ventricular function
How are PDAs managed?
Medical - IV indomethacin, ibuprofen in first 14 days of life
Surgical - cardiac catheter closure or ligation via open thoracotomy
What is ALCAPA?
Anomalous Left Coronary Artery from Pulmonary Artery
L heart therefore gets oxygen poor blood and undergoes ischaemia. Low BP in pulmonary artery can also cause reversal of flow over time so blood flows from LCA into pulmonary artery - pulmonary steal and worsening ischaemia
How many vessels are in the umbilical cord?
3 - 2 UAs and 1 UV
Where do the umbilical arteries branch off from?
Internal iliacs
What does the ductus venosus do?
Shunts blood across the Fetal liver to the IVC
What shunts blood across the nonfunctional Fetal liver? Into what?
Ductus venosus to the ivc
How does blood flow through the Fetal heart and why?
From R atrium into L atrium via foramen ovale
Because pulmonary vascular pressures are very high (hypoxic pulmonary vasoconstriction) which transmits back into RV, so pressure in R heart is greater than L and blood flows from R to L
What does the ductus arteriosus do?
Allows blood to flow from the pulmonary artery into the descending aorta at the isthmus, bypassing the nonfunctional Fetal lungs
What are the 2 methods the Fetal circulation uses to bypass the lungs?
Foramen ovale
Ductus arteriosus
What are the 3 shunts in the Fetal circulation?
Ductus venosus
Ductus arteriosus
Foramen ovale
What 2 major circulatory changes occur when the baby is born and what happens as a result of this?
Placenta disconnects from circulation
Lungs become functional and pulmonary pressure falls
RA and RV pressures fall; eventually to less than L sided pressures and flow reverses, closing the foramen ovale
What physiologically clamps the umbilical cord?
Wharton’s jelly
Within how long of birth does the foramen ovale usually close?
Few mins
Why does the ductus arteriosus close? What keeps it open before this?
Due to rising oxygen levels in the circulating blood
Prior to this the placenta produces prostaglandins which helps to keep it open. When this falls after birth the DA closes
3 conditions that have ductus dependent systemic circulation?
Coarctation
Critical aortic stenosis
Hypoplastic L heart syndrome
Which way does the blood flow in conditions with ductus dependent systemic circulation?
From pulmonary artery to aorta
4 conditions with ductus dependent pulmonary circulation? Which way does the blood flow?
Critical pulmonary stenosis Pulmonary atresia Tricuspid atresia Tetralogy of Fallot Blood flows from aorta to pulmonary artery
3 common L to R shunt heart defects?
VSD
PDA
ASD
2 common R to L shunt heart defects?
TOF
TOGA
What is the major presenting symptom of L to R shunts and stenotic heart disease/coarctation?
Breathlessness