CVS - Congenital Heart Defects Flashcards Preview

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Flashcards in CVS - Congenital Heart Defects Deck (25):

How common are congenital heart defects?

Which are the most common?

- Common (6-8 per 1000 births)

- Ventricular Septal Defects = most common
- Atrial Septal Defects = 2nd most common


What happens to the O2 concentration in the blood as a result of acyanotic defects?

O2 concentration in the blood is NOT lower than normal


What is an atrial septal defect?

How do they happen?

- An opening in the septum between the two atria, which persists after birth

- Foramen ovale doesn't close so blood still flows between atria after birth


What is the function of the foramen ovale?

- Permits right to left shunting of oxygenated blood via the inferior vena cava

- Allows bypassing of pulmonary circulation


Why are atrial septal defects acyanotic?

- Pressure in left atrium is HIGHER than pressure in right atrium

- Flow is mostly left to right

- No mixing of deoxygenated blood with oxygenated blood when being pumped around circulation


Where do atrial septal defects most commonly occur?

- Foramen ovale = ostium secundum and is most common

- Ostium primum = inferior septum but is less common


What is a patent foramen ovale?

- Failure of the foramen ovale to close

- Higher left pressure causes functional closure = no symptoms


When may a patent foramen ovale become a problem?

- Could be a route of a venous embolism to reach systemic circulation

- If pressure on right side of heart increases transiently

- Causes a paradoxical embolism


What is a ventricular septal defect?

- An opening in the interventricular septum

- Usually in the membranous portion


Are ventricular septal defects usually problematic?

- Not usually

- Left side pressure is much higher than right so blood flows from left to right


What is the ductus arteriosus?

- A vessel in the foetus

- Shunts blood from the pulmonary artery to the aorta when lungs are non-functional

- Usually closes after birth when there is a drop in pulmonary artery pressure


What is a patent ductus arteriosus?

What are the effects?

- Ductus arteriosus fails to close

- Blood flows from the aorta to the pulmonary artery after birth

- A mechanical murmur is heard in both systole and diastole


When can a patent ductus arteriosus become a problem?

- Chronic left to right shunting = vascular remodelling of pulmonary circulation and ↑ pulmonary resistance

- If pulmonary resistance > systemic resistance then the shunt reverses

- Causes ↑ pressure in the right heart (Eisenmenger syndrome)


What is coarctation of the aorta?

What happens as a result?

- Narrowing of the aortic lumen around the ligamentum arteriosum

- ↑ afterload of left ventricle = LV hypertrophy

- Upper limb and head aren't affected as blood supply emerges before coarctation


How can coarctation of the aorta be detected?

- Weak and delayed femoral pulse

- Upper body hypertension
(mild cases)

- Severe cases = heart failure at birth


Which CHDs are acyanotic?

- Atrial septal defects

- Patent foramen ovale

- Ventricular septal defects

- Patent ductus arteriosus

- Coarctation of the aorta


Which CHDs are cyanotic?

- Tetralogy of fallot

- Tricuspid atresia

- Transposition of the Great Arteries

- Hypoplastic Left Heart


What is tetralogy of fallot?

- 4 lesions together due to a single developmental defect

- Causes outflow portion of IV septum to be too far in the anterior and cephalad direction


What abnormalities does tetralogy of fallot cause?

- Ventricular septal defects

- Overriding aorta (aorta = directly over VSD instead of LV)

- Pulmonary Stenosis

- Right Ventricular Hypertrophy


What can pulmonary stenosis as a result of tetralogy of fallot cause?

- Persistent RV hypertrophy

- ↑ pressure in RV to overcome ↑ resistance in pulmonary artery

- ↑ RH pressure + VSD + Overriding aorta = Right to left shunting

- Deoxygenated blood mixes with oxygenated in systemic circulation = cyanosis


What is tricuspid atresia?

What can happen as a result?

- Tricuspid valve doesn't develop properly

- Blood can't get into right ventricle


If tricuspid atresia has taken place, how can blood flow to the lungs?

- Needs a complete right to left shunt of blood returning to right atrium

- Atrial septal defect/ patent foramen ovale
- Ventricular septal defect/ patent ductus arteriosus


What is transposition of the great arteries?

- Two parallel circulations that aren't connected instead of two in series

- RV is connected to aorta

- LV is connected to pulmonary trunk


Can a baby survive if transposition of the great arteries?


- Maintenance of ductus arteriosus/ formation of an atrial septal defect

- Allows two circulations to communicate


What is a hypoplastic left heart?

- Development of left ventricle and ascending aorta is poor

- Patent foramen ovale and atrial septal defect also present

- Patent ductus arteriosus = allows circulation

- Will die unless treated with surgery

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