congenital heart defects Flashcards
how can congenital heart lesions be categorised
acyanotic or cyanotic
what is cyanosis
blue-purple discoloration of the skin and mucous membranes caused by an elevated blood concentration of deoxygenated hemoglobin
in which direction is the shunt in an acyanotic defect
left to right shunt.
flow from left to right
in which direction is the shunt in a cyanotic defect
right to left shunt
give some examples of acyanotic lesions
atrial septal defect ventricular septal defect Patent Ductus Arteriosus Congenital Aortic Stenosis Pulmonic Stenosis Coarctation of the Aorta
give some examples of cyanotic lesions
Tetralogy of Fallot
Transposition of the Great Arteries
what is an atrial septal defect
a persistent opening in the interatrial septum after birth that allows direct communication between the left and right atria
where is the most common site of ASD
most common site is at the region of the foramen ovale, termed an ostium secundum ASD
what is a patent foramen ovale (PFO)
not a true ASD
the foramen ovale typically functionally closes in the days after birth, and it is permanently sealed by the age of 6 months through fusion of the atrial septa. A PFO remains when this fusion fails to occur.
clinically silent until the right atrial pressure becomes elevated (pulmonary hypertension or right-heart failure)
deoxygenated blood passes directly into the arterial circulation
what are the consequences fo ASD
- oxygenated blood from the left atrium is shunted into the right atrium
- increased pulmonary blood flow
- RV vol overload , leading to enlargement of right side of heart
- pulmonary hypertension is rare
- eventual right heart failure
what is a ventricular septal defect and where are they most commonly found
an abnormal opening in the interventricular septum
most often located in the membranous and muscular portions of the septum
what are the haemodynamic effects of ventricular septal defects
- left to right shunt
- LV volume overload
- pulmonary venous congestion
- eventual pulmonary hypertension
what is Patent Ductus Arteriosus
The ductus arteriosus is the vessel that connects the pulmonary artery to the descending aorta during fetal life. PDA results when the ductus fails to close after birth, resulting in a persistent connection between the great vessels
what are the consequences of Patent Ductus Arteriosus
Prenatally, when the pulmonary vascular resistance is high, blood is diverted away from the immature lungs to the aorta. As the pulmonary resistance drops postnatally, the shunt reverses direction, and blood flows from the aorta into the pulmonary circulation instead. Because of this left-to-right shunt, the pulmonary circulation, left atrium, and LV become volume overloaded. This can lead to left ventricular dilatation and left-sided heart failure
what is Congenital Aortic Stenosis
when the aortic valve has bicuspid leaf structure instead of three-leaflet configuration
what are the consequences of Congenital Aortic Stenosis
the valvular opening has narrowed so left ventricular systolic pressure must increase to pump blood across the valve into the aorta.
LV hypertrophies
The high-velocity jet of blood that passes through the stenotic valve may damage the aortic wall and contribute to dilatation of that vessel.
what is Pulmonic Stenosis
Obstruction to right ventricular outflow due to stenosis of pulmonary valve
what is the consequence of pulmonary stenosis
right ventricular outflow, which leads to increased RV pressures and chamber hypertrophy
what is Coarctation of the Aorta and what are the effects
discrete narrowing of the aortic lumen
the LV faces an increased afterload
development of left ventricular hypertrophy
what is the Tetralogy of Fallot
1) a VSD caused by anterior malalignment of the interventricular septum
2) pulmonary stenosis
3) right ventricular hypertrophy
4) overriding aorta
what happens in transposition of great arteries
1)RV is connected to aorta
2)LV is connected to pulmonary artery
this is not viable
this is a =n example of bidirectional shunting
what happens in hypoplastic left heart syndrome
1) left ventricle is underdeveloped
2) ascending aorta very small
3) right ventricle supports systemic circulation
4) obligatory right to left shunt
what is pulmonary atresia
the pulmonary valve doesn’t develop properly, preventing it from opening. Blood can’t flow from the right ventricle to the lung
blood flow to lungs via Patent ductus arteriosus
what is tricuspid atresia
lack of development of tricuspid valve leaving no inlet to the right ventricle.
