Congential Heart Defects Flashcards
What is a congenital heart defect?
An abnormality(s)/defect(s) that a child is born with related to the heart
Which circulation has the lower resistance, pulmonary or systemic?
Pulmonary circulation = lower resistance
What is the rough O2 saturation in all of the right side of the heart and the pulmonary trunk?
67%
Which chamber of the heart has the lowest overall pressure?
Right atrium
Which chambers of the heart have the lowest pressures? The atria or ventricles?
Atria = lowest (Right lowest then left)
Ventricles = higher (right ventricle lower than left ventricle, right ventricle has a higher pressure than the left atrium)
What is a shunt?
Passage connecting two channels/chambers leading to blood diversion or fluid diversion
What is meant by a left to right shunt?
When blood is redirected form the left side of the heart to the right side of the heart
What causes a left to right shunt to occur in the heart?
A hole
What effect does a left to right shunt have on blood flow around the body?
Increased blood flow to lungs
Some blood from left side re-enters back into pulmonary circulation
What negative effect can be caused by a left to right shunt in the heart?
Increased pulmonary artery and pulmonary venous pressure
What causes a right to left shunt?
A hole
+
Distal obstruction
Why does a left to right shunt not require an obstruction to happen?
Pressure of pump of left side of heart is greater than the right
Blood will naturally flow down pressure gradient from left side of the heart to right side of the heart through the hole
Why does a right to left shunt require a hole and distal obstruction?
Something is required to increase the pressure in the right side of the heart so that it exceeds the left side of the heart which is naturally at a higher pressure
What are the 2 classifications of congenital heart defects?
Acyanotic
Cyanotic
What does Acyanotic mean?
No blue discolouration present
What does cyanotic mean?
Blue discolouration present
What type of shunting causes Acyanotic congenital heart defects?
Left to right shunts
Why do left to right shunts cause Acyanotic congenital heart defects?
All blood that is in systemic circulation is oxygenated
What type of shunting causes cyanotic congenital heart defects?
Right to left shunts
Why do right to left shunts cause cyanotic congenital heart defects?
Deoxygenated blood enters systemic circulation
Where can shunts (holes) develop that result in left to right shunting (Acyanotic defects)?
(Just holes no obstructions)
Atrial septal defects
Ventricular septal defects
Atria-ventricular septal defects
Aorto-pulmonary defect (Patent ductus arteriosus)
What is a sinus venosus defect?
Atrial septal defect
Wall between SVC and right sided pulmonary veins not closed
Causes increased flow into pulmonary circulation from systemic circulation
What is a Ostium Secundum atrial defect?
Atrial septal defect
Hole in the CENTRE of the atrial septum
What is ostium primum defect?
Atrial septal defect
Hole in LOWER part of atrial septum near tricuspid and mitral valve
What affect do atrial septal defects have on blood flow/haemodynamics?
Left to right shunting
Increased pulmonary flow
RV volume overload
Right heart failure (hypertrophy of right heart)
What is a perimembranous septal defect?
Ventricular septal defect
Hole in membraneous part of ventricular septum (upper part)
Left to right shunting
What is Inlet Ventricular septal defect?
Hole in ventricular septum near to tricuspid and mitral valve
Just underneath the valves
Left to right shunting
What is Apical muscular defect?
Ventricular septal defect
Muscular component of ventricular septum near apex of ventricles doesn’t fully form leaving 1 or more holes
Left to right shunting
What is a sub arterial septal defect?
Ventricular septal defect
Hole in ventricular septum just beneath the valves of the great arteries (aorta and pulmonary trunk)
What affect to Ventricular septal defects have on blood flow/haemodynamics?
Left to right shunting
LV volume overload (since more blood being returned back to pulmonary circulation so more blood returned to LV)
Pulmonary venous congestion
Pulmonary hypertension
Why do ventricular septal defects (VSDs) cause LV volume overload and pulmonary venous congestion?
Increased amount of blood in pulmonary circulation leads to increased blood flow into left side of heart
Pulmonary veins back up with blood as left side gets overloaded with blood
Give some examples of atrioventricular septal defects:
No mitral valve or tricuspid valve
Holes between the atria and ventricle
What is aortic stenosis?
Aortic valve does not open correctly so its harder for blood to pass through to the aorta
What affect does Aortic stenosis have on the heart?
Increase in after load (LV HYPERTROPHY)
Left sided heart failure
Congestive heart failure
What is coarctation?
Narrowing of the aorta at the isthmus near the ligamentum arteriosum (former ductus arteriosus) after the branches of aorta given off
What is the Tetralogy of Fallot?
Congenital heart condition characterised by 4 heart defects
What are the 4 characteristic heart defects of The Tetralogy of Fallot?
Remember POSH:
Pulmonary stenosis
Overriding aorta
ventricular Septal defect
right ventricular Hypertrophy
Describe the pathology of Tetralogy of Fallot:
Eccentric/off centre spiral septum formation leads to the aorta taking up most then pulmonary trunk a little bit
-over riding aorta caused
This narrows the pulmonary trunk
-pulmonary stenosis
This means RV must work harder due to it being narrow
-RV Hypertrophy
Due to eccentric spiral septation, inter-ventricular walls don’t line up with endocardial cushions
-Ventricular Septal Defect
What affect does coarctation have on the heart?
Increased afterload of LV
LV hypertrophy
How would femoral pulse be affected by coarctation and how would carotid pulse be affected and why are they different?
Femoral pulse reduced
Carotid pulse unaffected
Region where arch of aorta branches to upper body is proximal to coarctation, so narrowing happens after the branches to the upper body form
Would Tetralogy of Fallot by cyanotic or Acyanotic and why?
Cyanotic
RV hypertrophy causes pressure on the right side of the heart (in RV) to be greater than the left leading to oxygenated blood entering systemic circulation
What is Tricuspid Atresia?
What must occur for somebody to survive with this?
No tricuspid valve develops
For survival a Right to left shunt between atria must develop
VSD or PDA leads to blood flow to lungs
What is transposition of the great arteries?
RV connected to aorta
LV connected to pulmonary artery
How can somebody with transposition of the great arteries survive?
Shunting needed
Patent Ductus arteriosus
Shunt needed to allow oxygenated blood to reach systemic circulation
Why can a baby in uteri survive with transposition of the great arteries?
Ductus arteriosus is a shunt that exists between pulmonary artery and aorta in utero
Allows flow of oxygenated blood into aorta from through the pulmonary artery
Once born this ductus arteriosus seals so deoxygenated blood is transported around the body (cyanotic) = death
What is hypoplastic left heart?
The left ventricle is underdeveloped and the ascending aorta is very small
Right ventricle must support systemic circulation
Right to left shunt must be present to survive (like patent ductus Arteriosus)
In hypoplastic left heart , what must be present in order for survival?
Right to left shunt
Atrial septal defect
Patent ductus arteriosus
What can be given to a baby to keep the Dutus arteriosus open so they can survive with a hypoplastic left heart?
Prostoglandins
What is pulmonary atresia?
How can a baby with this survive?
No Right ventricle valve//outlet
RIght to left Arial shunt
Ductus arteriosus needs to be kept open to allow blood to get oxygenated
What defect/intervention must happen in pulmonary atresia for survival?
Patent Ductus arteriosus so right side blood can be oxygenated at the lungs
What other defect must a child have to survive with pulmonary atresia?
Patent Ductus Arteriosus
What are the 3 normal shunts in the embryo?
Ductus arteriosus (between the great vessels)
Foreamen ovale (between atria)
Ductus venosus (bypasses liver)
What should the ductus arteriosus form once baby is born?
Ligamentum arteriosum
What should the foramen ovale form once the baby has been born?
Fossa ovalis
What should the Ductus venosus become once th baby is born?
Ligamentum venosum
