CVS 3 Congenital Heart Disease Flashcards
What is the incidence rate of congenital heart disease?
6-8/1000 births
What are the most common defects?
Ventricular Septal Defects (VSD) followed by Atrial Septal Defects (ASD)
What is transposition of the great vessels?
Where conotruncal septum doesnt take a spiral course and so vessels connected to wrong chambers
What is tetralogy of fallot? (brief)
A group of 4 lesions occurring together as a result of a single developmental defect placing the outflow portion of the interventricular septum too far in the anterior and cephalad directions
What does it mean for a heart defect to be acyanotic?
defect not resulting in lower than normal blood oxygen concentration
What is the incidence of ASD?
67 per 100,000 live births
Why are ASDs acyanotic?
left atrial pressure is higher than right atrial pressure so blood moves from left to right meaning no mixing of deoxygenated and oxygenated blood is pumped out through the aorta
What is the most common site for an ASD?
Foramen ovale (Ostium secundum ASD). Ostium primum ASDs occur and inferior part of septum and is less common
What is a Patent Foramen Ovale?
Not a true ASD. May be present in ~20% of population and clinically silent as higher left atrial pressure causes functional closure of the flap valve.
How does a patent foramen ovale relate to embolisms?
can be the route by which venous embolisms reach the systemic circulation if there is even a transient increase in right side pressure. Called a paradoxical embolism
Where are ventricular septal defects most common?
In the membranous portion
Which way does blood move in VSDs?
Left to right
What is a patent ductus arteriosus?
Failure for ductus arteriosus to close after birth meaning that blood will flow from the aorta to the pulmonary artery.
What can be heard in patent ductus arteriosus?
Mechanical murmur heard constantly throughout systole/diastole as pressure always greater in aorta
What problems can patent ductus arteriosus cause?
Vascular remodelling of pulmonary circulation and increase in pulmonary resistance
If pulmonary resistance increases to more than that of systemic circulation shunt reverses pressures on right side of heart increase (Eisenmenger Syndrome)
What is coarctation of the aorta?
Narrowing of aortic lumen in area of ligamentum arteriosum increasing afterload on left ventricle and can lead to ventricular hypertrophy. Blood flow to head and upper limbs not compromised as narrowing further downstream but rest of body is.
When are symptoms seen of aortic coarctation?
in severe cases infant may present with symptoms of heart failure shortly after birth. In mild cases not detected until adult life.
What signs will be present in aortic coarctation?
weak femoral pulses and upper body hypertension
What is a cyanotic heart defect?
Defect with which there is mixing of oxgenated and deoxygenated blood that is pumped around the systemic circulation
What are the four abnormalities in tetralogy of fallot?
VSD
Overriding aorta
Pulmonary stenosis (variable degree)
Right Ventricular Hypertrophy (variable degree)
What causes the right ventricular hypertrophy in tetralogy of fallot?
the pulmonary stenosis causes persistence of the foetal right ventricular hypertrophy as RV operates at a higher pressure to pump blood through pulmonary artery
Which way does blood move in tetralogy of fallot and why?
there is right to left shunting due to the VSD and increased pressure on the right side of the heart. The overriding aorta picks up blue blood as sits over VSD anyway
What does the level of severity depend on in tetralogy of fallot?
the severity of pulmonary stenosis. Can present in infancy and adulthood
What is tricuspid atresia?
Lack of development of tricuspid valve meaning no inlet into the right ventricle. There must be a complete right to left shunt of all blood returnin to RA (via ASD or PFO) and a VSD to allow blood flow to the lungs. This is cyanotic.
What is a hypoplastic left heart?
Where left ventricle and ascending aorta fail to develop properly. A PFO or ASD are present and blood supply to systemic circulation is via a PDA. Lethal without surgical correction
