CVS 4 Congenital Heart Disease Flashcards
Causes of congenital heart diseases
Genetics
Environment- teratogenicity from drugs + alcohol
Maternal infections
What is teratogenicity?
Agent which causes malformation of embryo
e.g. drugs + alcohol whilst pregnant
What are some genetic conditions which have a higher chance of congenital heart disease?
Down’s syndrome
Tuner’s syndrome
Marfan’s syndrome
Two types of congenital heart defects
Acyanotic
Cyanotic
What is the shunt in acyanotic CHD?
Left to right shunt
Blood in system system fully saturated
pO2 is maintained
What is the shunt in cyanotic CHD?
Right to left
Blood mixing > deoxygenated blood in systemic circulation
Decrease in pO2
Physical presentation of cyanotic CHD?
Blue discolouration of skin + lips
What causes an atrial septal defect?
- Opening in wall between atria - foramen ovale
- Due to underdevelopment of septum primum or secundum
- Hole between atria
What is caused by underdevelopment of septum primum or secundum?
Atrial septal defect
What is the shunt in ASD?
What is the effect?
L > R shunt
Increased pulmonary blood volume > damage to vasculature > resistance > pulmonary hypertension (rare) > pulmonary oedema due to fluid forced out
Right side heart failure
What can happen in ASD if pulmonary hypertension is left untreated?
RA pressure > LA pressure
R > L shunt
Mixing of blood - cyanotic
Eisenmenger’s syndrome
What causes a ventricular septal defect?
Primary interventricular foramen remains open
Septum doesn’t develop properly
Hole between ventricles
What is caused by undevelopment of the septum?
Ventricular septal defect
What is the shunt in VSD?
What is the effect if left untreated?
L > R shunt
Pulmonary hypertension
Right sided heart failure
What is the cause of an atrioventricular septal defect?
Failure of endocardial cushion development
Holes between atria + ventricles
What condition is AVSD common in?
Down’s syndrome
What CHD is common in Down’s syndrome?
Atrioventricular septal defect
What is the shunt in AVSD?
L > R shunt
What causes aortic/pulmonary stenosis?
Semilunar valves don’t develop properly - narrow when born
What is the common defect in the aortic valve in aortic stenosis?
2 leaflets instead of 3
What can aortic/pulmonary stenosis causes?
- Heart has to work harder to push blood through stenosed valves
- Ventricular hypertrophy
- Heart failure
What is the cause of coartication of aorta?
Congenital narrowing of aorta
Common site of coartication of aorta
Ductus arteriosus area
Presentation of coartication of aorta
Radial-femoral delay
Strong radial pulse
Weak femoral pulse
Presentation of coartication of aorta if narrowing is between brachiocephalic + left subclavian artery
Radial-radial pulse delay
Delay in both wrists
Effect of coartication of aorta
- Increased pressure upstream
- Increased risk of aneurysms of aortic arch
- Increased risk of aortic root dilation > aortic valve regurgitation
What is aortic valve regurgitation?
Aortic valve doesn’t close properly
What is the cause of patent ductus arteriosus?
Ductus arteriosus remains open after birth
What happens in PDA?
What are the effects?
Ductus arteriosus doesn’t close after first breath
Blood flows from aorta to PA - acyanotic
Increased volume in PA > increased afterload for RV
Right sided heart failure
What is the cause of tricuspid atresia?
Tricuspid valve fails to form
What is the effect of tricuspid atresia?
What other CHDs do babies with TA have?
- Blood cant flow form RA > RV
- Babies have ASD + VSD to allow blood into pulmonary circulation
- ASD - R > L shunt of all venous return
- VSD - allows blood into RV + out through PA
- Blood mixing > central cyanosis
What is the cause of pulmonary atresia?
Pulmonary valve fails to form
What other CHDs are in babies with pulmonary atresia?
VSD - deoxygenated blood RV > LV
PDA - lows blood to pulmonary circulation
What is given to newborns in transposition of great arteries before surgery to keep them alive?
Prostaglandins
What causes transposition of great arteries?
Aorticopulmonary septum forms but doesn’t spiral
RV connected to aorta
LV connected to pulmonary artery
What are the 4 defects in the tetralogy of fallot?
POSH
Pulmonary stenosis
Overriding aorta
Septal defect (ventricular)
Hypertorphy of RV
Why is there hypertrophy of RV in tetralogy of fallot?
To compensate for stenosis in PA
What causes a hypoplastic heart?
Underdevelopment of left ventricle
Due to mitral or aortic valve stenosis in utero
Effect of hypoplastic heart
R > L shunt
cyanotic
Small ascending aorta if aortic valve is stenosed
What CHDs are in patients with hypoplastic heart?
ASD + PDA
ASD - allow oxygenated blood to flow to PA
PDA - allows this blood into aorta to systemic system
What causes univentricular heart?
Ventricular septum doesnt form at all
What does failure of ventricular septum formation cause?
Univentricular heart
What does underdevelopment of the left ventricle cause?
Hypoplastic heart
What does the lack of spiralling of the aorticopulmonary septum cause?
Transposition of great arteries
What does failure of pulmonary valve formation cause?
Pulmonary atresia
What does failure of the tricuspid valve formation cause?
Tricuspid atresia
What does failure of the ductus arteriosus closing after birth cause?
Patent ductus arteriosus
What does narrowing of the aorta cause?
Coartication of aorta
What does underdevelopment of the semilunar valves cause?
Aortic/pulmonary stenosis
What does failure of the endocardial cushion development cause?
Holes between atria + ventricles
Atrioventricular septal defect
What does underdevelopment of the septum cause?
Ventricular septal defects
What condition occurs if the primary interventriclar foramen remains open?
Ventricular septal defects
What defect is most likely if a newborn baby has continuous murmur + no signs of cyanosis?
Patent ductus arteriosus
What defect is most likely if a newborn baby has a loud systolic murmur in left sternal border + no signs of cyanosis?
Ventricular septal defect
List the acyanotic congenital heart defects
- atrial septal defect
- ventricular septal defect
- atrioventricular septal defect
- aortic/pulmonary stenosis
- coartication of aorta
- patent ductus arteriosus
List the cyanotic congenital heart defects
- tetralogy of fallot
- tricuspid/pulmonary atresia
- transposition of great arteries
- uni ventricular heart
- hypoplastic heart
