Session 3 Flashcards
Congenital Heart Disease
In terms of pressure gradient, which way does blood flow?
From high to low
What are the acyanotic congenital heart defects? (5)
Atrial septal defect (ASD) Patent foramen ovale (PFO) Ventricular septal defect (VSD) Patent ductus arteriosus (PDA) Coarctation of the aorta
What are the cyanotic congenital heart defects? (5)
Tetralogy of Fallot Tricuspid atresia Transposition of the great arteries Hypoplastic left heart Eisenmenger's syndrome
What is an atrial septal defect (ASD)
An opening in the septum between the two atria. Failure to close the foramen ovale, or an abnormal communication allows blood to continue to flow between the atria.
Flow is from left to right.
No mixing of deoxygenated blood with oxygenated blood being pumped around systemic circulation. (acyanotic)
What two types of atrial septal defect (ASD) are there?
Ostium secundum ASD - opening at foramen ovale
Ostium primum ASD - inferior portion of the septum (less common)
What is a patent foramen ovale (PFO)?
Not a true ASD -> clinically silent since higher left atrial pressure causes function closure of the flap valve.
Only a problem when a venous embolism enters the left heart due to a transient increase in right side pressure.
What is a ventricular septal defect (VSD)?
Abnormal opening in the interventricular septum.
(most common in the membranous portion of the septum)
Left to right flow (Left ventricular pressure higher than right ventricular pressure).
What is a patent ductus arteriosus (PDA)?
Failure to close the ductus arteriosus (exists to shunt blood from pulmonary artery to aorta before lungs are functioning in the foetus -> closes when pulmonary artery pressure drops).
Blood will flow from aorta to pulmonary artery.
How can a chronic left to right shunt result in right to left shunting (cyanosis)?
Eisenmenger syndrome.
Chronic left to right shunting can lead to vascular remodelling of the pulmonary circulation increasing pulmonary resistance. If the resistance of the pulmonary circulation increases beyond systemic circulation, the shunt will reverse direction as right heart pressure increases.
What is a coarctation of the aorta?
Narrowing of the aortic lumen in the region of the ligamentum arteriosum (former ductus arteriosus).
Narrowing increases the afterload on the left ventricle -> left ventricular hypertrophy. (Blood flow to the head and upper limbs is not compromised.)
Symptoms of heart failure shortly after birth.
Femoral pulses will be weak and delayed, upper body hypertension.
What is tetralogy of Fallot?
Group of 4 lesions occuring together as the result of a single developmental defect -> outflow portion of interventricular septum is anterior and cephalad.
What are the four anomalies of tetralogy of Fallot?
VSD, overriding aorta, right ventricular hypertrophy and pulmonary stenosis.
Pulmonary stenosis causes persistence of right ventricular hypertrophy. The increased right heart pressure and VSD and overriding aorta causes right to left shunting.
This causes episodes of cyanosis.
What is tricuspid atresia?
Lack of development of the tricuspid valve -> no inlet to right ventricle.
Must be a complete right to left shunt of blood (ASD or PFO) and a VSD or PDA to allow blood flow to lungs.
What is the transposition of the great arteries?
Two unconnected parallel circulations form instead of two circulations in series.
Right ventricle connects to aorta and left ventricle to pulmonary trunk.
Results in death unless PDA or ASD is formed.
How does a hypoplastic left heart form?
Left ventricle and ascending aorta fail to develop properly.
A PFO or ASD are present and blood supply to systemic circulation is by PDA. (Without surgery this results in death).
