Give four basic facts you absolutely completely without a doubt have to know about the heart
1. Right Ventricle pumps deoxygenated blood to lungs 2. Pulmonary circulation has low resistance 3. Left ventricle pumps oxygenated blood at systemic blood pressure to Aorta 4. Each ventricle is morphologically adapted for its task
What two features are required for a right to left shunt?
A hole and a distal obstruction
What are the two classes of congenital HD?
Acyanotic and Cyanotic
What are the two main causes of acyanotic congenital heart disease?
Left to right shunts Obstructive lesions
What are the four main causes of cyanotic congenital heart disease?
– Tetralogy of Fallot (VSD/Pulm stenosis …) – Transposition of the Great Arteries – Total Anomalous Pulmonary Venous Drainage – Univentricular Heart
What are the four haemodynamic effects of atrial septal defects?
1. Increased pulmonary blood flow 2. RV Volume overload 3. Pulmonary hypertension is rare 4. Eventual Right Heart Failure
What are four haemodynamic effects of ventricular septal defects?
1.Left to right shunt 2. LV Volume overload 3. Pulmonary Venous congestion 4. Eventual pulmonary hypertension
How common is a ventricular septae defect?
Makes up 25% of all forms of congenital heart defects
What is the most common site for a ventricular septal defect, and why does it occur?
Membranous part of IVS develops seperatel from muscular part, so is a common site for VSD
In which direction does blood move in an VSD?
From left to right, due to high left ventricular pressure as compared to the right.
What single general effect does a VSD have?
Increases pulmonary blood flow
What are the 6 effects of a LARGE congenital VSD?
o Progressive obliteration of the pulmonary vasculature > pulmonary arterial pressure = systemic pressure \ shunt may be reduced/reversed > central cyanosis o Pulmonary hypertension o Pneumothorax o Breathlessness o Pulmonary oedema o Lung damage
What are the 2 moderate effects of a VSD?
Fatigue Dyspnoea with cardiac enlargement
What is the least common type of VSD?
A defect in the muscular part
What does an atrial septae defect allow?
Left to right shunts
What happen to people with an ASD above the age of 30?
* Above age of 30, there may be an increase in pulmonary vascular resistance > pulmonary hypertension > atrial arrhythmias esp. atrial fibrillation are common
What type of ASD is responsible for 75% of all ASD?
* Ostium secundum (foramen ovale) (75%) o Abnormally large opening in the atrial septum at the site of the foramen ovale and the ostium secundum
Why are both ASD and VSD's acyanotic?
Because oxygenated blood moves from left to right due to pressure differences - No deoxygenated blood in systemic circulation
What is the less common version of ASD?
An ostium primum ASD in the inferior portion of the septum (15%)
What is a patent foramen ovale and how common is it?
Foramen ovale remains open after birth, present in 20% of population
Why is a PFO not a true atrial septal defect?
Because higher left atrial pressure causes functional closure of the flap valve
Why can a PFO be clinically significant?
Can be the route by which a venous embolism reaches the systemic circulation if pressure on the right side of the heart increases even transiently
What is the effect of a left to right shunt?
* Left heart pressure > right heart pressure * Pulmonary resistance low so RV is easily compliant
What is a patent ductus arteriosus?
Vessel which sunts blood from the pulmonary artery to the aorta remains open after birth.
Which way does blood flow in a PDA?
From the aorta (high pressure) to athe plmonary artery (low pressure)
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What can chronic left to right shunting result in?
Vascular remodelling of the pulmonary circulation and an increase in pulmonary resistance.
What happens if there is an increase in pulmonary resistance due to chronic left to right shunting? What is the name of the syndrome?
If pulmonary resistance increases beyone that of systemic circulation, the shunt will reverse direction as pressures on the right side of the heart increase. Eisenmenger syndrome
What is coarctation of the aorta?
A narrowing of the aortic lumen in the region of the ligamentum arteriosum (former ductus arteriosus)
What effect does coarctation of the aorta have on the heaart?
Increases afterload on left ventricle, which can lead to left ventricular hypertrophy
Why are the upper limbs and head usually unaffected by aortic coarctation?
Because the vessels to the head and upper limbs usually emerge proximal to the coarctation.
What happens if coarctation of aorta severe?
Infant presents with symptoms of heart failure shortly after birth
What are the symptoms of a mild coarctation of the aorta?
Weak, delayed femoral pulse and upper body hypertension
What is cyanosis?
Cyanosis: increased deoxygenated blood circulating in the body > blue appearance
What is the tetralogy of fallot?
A group of 4 lesions occurring together as the result of a single developmental defect which places the outflow portion of the interventricular septum too far in the anterior and cephalad directions.
What are the four features of the aptly named tertalogy of fallot?
Overriding Aorta VSD Pulmonary Stenosis Right Ventricular hypertrophy
What does pulmonary stenosis cause in tetralogy of fallot?
Persistence of the foetal right ventricular hypertrophy as the right ventricle must operate at a high pressure to pump blood through the pulmonary artery. - Right ventricular hypertrophy causes increased pressure and right to left shunting through VSD and overriding aorta - The causes mixing of deoxygenated blood with oxygenated blood - Cyanosis results
What does the severity of cyanosis depend on in the tetralogy of fallot?
The severity of pulmonary stenosis
What are the clinical features of the tetralogy of fallot
o Dyspnoea or fatigue o Cyanosis o Chronic hypoxaemia o Clubbing
What is tricuspid artesia?
Lack of development of the tricuspid valve, leaving no inlet to the right ventricle
What does a tricuspid atresia mean?
There must be a complete right to left shunt of all the blood returning to the right atrium (ASD or PFO) and a VSF or PA to allow blood flow to the lungs
What is transpostion of the great arteries?
Right ventricle connected to the aorta and left ventricle to the pulmonary trunk
What condition is commonly associated with transposition of the great arteries?
VSD in 50% of cases
How does transpostion of the great arteries occur in development?
Contruncal septum does not adopt spiral course
What is the path of blood when transposition of the great arteries has occured?
* \ deoxygenated blood from systemic veins > systemic circulation * & oxygenated blood from pulmonary veins > lungs
What is the chief clinical symptom when transposition of the great arteries occurs
Cyanotic blue baby Not compatible to life
How can transposition of the great arteries be fixed
A shunt must be maintained or created immediately following birth in order to allow two circulations to comminicate Most commonly the ductus arteriosus maintained, or ASD formed.
What is total anomalous pulmonary venous drainage
* All 4 pulmonary veins drain into vena cava or the right atrium Systemic and pulmonary venous blood mix in the right atrium
What is univentricular heart?
Atria drain into one ventricle
What is aortic stenosis caused by?
Senile calcification - inflammatory process
What happens in aortic stenosis?
* Leaflets now stiff > reducing systolic opening > increased LV pressure
What are the symptoms of aortic stenosis?
* Exercise induced angina, syncope & heart failure due to ischaemia of LV myocardium
What is aortic atresia?
* No LV outlet > impeded blood flow from LV * Only source of blood flow via PDA
What is pulmonary stenosis caused be?
* Usually due to a congenital lesion > rubella
What does pulmonary stenosis cause?
* Obstruction to RV systole > RV hypertrophy > RA hypertrophy * Fatigue, sycope and right heart failure
What is pulmonary artresia?
* No RV outlet * R to L shunt of entire venous system * Blood flow to lungs via PDA
Why would a patent ductus arteriosus form?
If duct is malformed, it will not close If they lack the mechanism to clsoe
What does a PDA cause?
Aorta to pulmonary shunt, increased venous return to left heart Left ventricular overload
What happens if shunt is too large in PDA?
o Left heart failure (in later adult life) o Pulmonary hypertension
Why does systemic hypertension result from coarctation of the aorta?
Decreased renal perfusion
What heart defect is shown in the picture?
Tetralogy of fallot
What does D show?
Narrowing of the pulmonary valve (stenosis)
What is C, and why does it come about?
Thickening of right ventricle wall, which hypertrophies due to higher pressure required to pump blood through pulmonary stensosis
What does A show?
Displacement of aorta over ventricular septal defect
What does B show?
Ventricular septal defect - opening between the left and right ventricles
Give the incidence/100,000 births for the following
Atrial septal defect
Patent Foramen Ovale
Ventricular septal defect
Give the incidence per 100,000 births for the following
Patent ductus arteriosus
Coarctation of the aorta
Tertalogy of Fallot
Give the incidence per 100,000 births for the following
Transposition of the great arteries
Hypoplastic left heart
What is hypoplastic left heart?
Left ventricle fails to develop properly, with a PFO or ASD also present, with blood supply to systemic circulation via PDA.