Congenital Heart Disease

Question 1

What is congenital heart disease?

Answer 1

Abnormality of the heart structure that is present at birth (inherited/genetic disease tend not to come under this)

Also, it is a gross structural abnormality of the heart or intrathoracic great vessels that is actually or potentially of functional significance

Question 2

3 examples of congenital heart disease?

Answer 2

Ventricular-septal defect (VSD)
Patent Dustus Arteriosus (PDA)
Atrio-ventricular septal defect (AVSD)

Question 3

How does congenital heart disease present?

Answer 3

During screening (antenatal scan or newborn baby check)

Well baby with clinical signs

Unwell baby - cyanosis, shock, cardiac failure

Look carefully at babies with other congenital/genetic abnormalities, e.g: Down’s syndrome (40-50% have a congenital heart disease)

Question 4

When does congenital heart disease present and with what symptoms at these times?

Answer 4

Antenatally

Soon after birth - cyanosis

Day 1-2 baby check - murmurs, abnormal pulses, cyanosis

Days 3-7 - sudden circulatory collapse, shock, cyanosis, sudden death

4-6 weeks - sign of cardiac failure (reduced feeding, failure to thrive, breathlessness, sweatiness)

6-8 week GP check - incidental finding of murmurs at other clinical contacts

Question 5

Why is the first week particularly important?

Answer 5

Around days 3-7, the ductus arteriosus closes and, if the baby has circulation dependent on its patency, it is potentially fatal

Question 6

What does antenatal screening involve?

Answer 6

Ultrasound at 18-22 weeks gestation allows a 4-chamber heart view and outflow tract view

Question 7

Disadvantages of antenatal screening?

Answer 7

Sensitivity is very variable and dependent on:
Operate experience and training
Maternal characteristics, e.g: fat tissue, etc

Need for expert follow-up/detailed foetal echocardiography and counselling

Question 8

Advantages of antenatal screening?

Answer 8

Outcomes probably better for major disease if it is antenatally detected:
Avoid cardiovascular collapse, undiagnosed death, etc
Minimise hypoxia
Improve condition at time of going to surgery

Question 9

What does newborn screening involve?

Answer 9

Clinical examination at around 24 hrs of age, inc. checking femoral pulses, heart sounds and presence of murmurs

In some regions, inc. measurement of pre and post-ductal saturation (right hand for pre-ductal and either foot for post-ductal)

Question 10

What do pre and post-ductal saturations indicate?

Answer 10

Low sats overall could imply cardiac or respiratory disease

Difference of 3% or more between pre and post-ductal implies right to left shunt at ductus

Question 11

Effectiveness of newborn screening?

Answer 11

More than half the infants with congenital heart disease are missed by this; around 1/3 of infants with life-threatening heart abnormalities leave hospital undiagnosed

Murmurs are common in normal babies, due to remaining pressure differences and closure of the ductus arteriosus

Question 12

Causes of cyanotic heart disease?

Answer 12

Any condition causing deoxygenated blood to bypass lungs and enter the systemic circulation, e.g: PPHN

Any condition where mixed oxygenated and deoxygenated blood enters the systemic circulation from the heart, e.g: PDA

Question 13

Cyanotic appearance?

Answer 13

Bluish discolouration; if in doubt, measure stats

Question 14

Symptoms of cardiac disease causing cyanosis?

Answer 14

Tend to be blue with little/no respiratory distress; may have pre-post ductal differential

Question 15

Symptoms of respiratory disease causing cyanosis?

Answer 15

Associated with increased work of breathing and X-ray changes

Question 16

Symptoms of PPHN causing cyanosis?

Answer 16

Often seen in otherwise very unwell babies; typical to have a LARGE pre-post ductal differential

Question 17

What is transposition of the great arteries?

Answer 17

Essentially, aorta and pulmonary artery swap positions; so, aorta is the ouflow for the right ventricle and pulmonary artery is the outflow for the left ventricle
Blood in the aorta goes to left side of the heart without being deoxygenated

Question 18

Treatment of transposition of the great arteries?

Answer 18

Key to survival: PFO (Patent Foramen Ovale)

Via umbilical vein, a catheter is inserted into the IVC, into the right atrium and through the foramen ovale; a balloon is inflated and pulled through to make the foramen larger and allow more blood shunting
This is done to allow time until arterial switch surgery can be done (swap aorta and pulmonary artery)

Question 19

What are duct-dependent lesions?

Answer 19

Any condition in which the pulmonary or systemic circulation is dependent on the patency of the ductus arteriosus (PDA)e.g: any condition where there is reduced blood flow from left heart

If not detected earlier, babies present with circulatory collapse when the duct closes

Question 20

Presentation of baby with duct-dependent lesion?

Answer 20

3-5 day old infant suddenly pale, tachypnoeic and distressed and rapidly become more unwell

Clinical signs inc. pallor, prolonged CRT, poor/absent pulses, hepatomegaly, crepitations and increased work of breathing

Profoundly acidotic

Differential - inc. sepsis, metabolic conditions

Question 21

Treatment for duct-dependent lesions?

Answer 21

Diagnosis before baby becomes unwell is desirable in duct-dependent conditions

ABC - support airway and breathing as necessary

Commence low-dose PGE2 immediately to maintain duct patency

Multi-system supportive treatment

Watch for apnoea (side effect of PGE2) but avoid intubation and ventilation if possible

Move to cardiac surgical centre

Question 22

Two types of duct-dependent conditions?

Answer 22

Duct-dependent systemic circulation, e.g: hypoplastic left heart, critical aortic stenosis, interrupted aortic arch, critical coarctation of the aorta

Duct-dependent pulmonary circulation, e.g: tricuspid atresia, pulmonary atresia

Question 23

What is interruption of the aortic arch?

Answer 23

Aortic arch ends prematurely

ADD PICTURE

Question 24

What is pulmonary atresia?

Answer 24

Pulmonary valve orifice fails to develop, preventing outflow from right ventricles

ADD PICTURE

Question 25

What is tetralogy of fallot?

Answer 25

Most common cyanotic heart disease
Usually, a right-to-left shunt exists, in which higher resistance to right ventricular outflow results in more severe cyanosis symptoms

Question 26

What is total anomalous pulmonary venous connections (TAPVC)?

Answer 26

Veins from the lungs attach to the heart in abnormal positions and this problem means that oxygenated blood enters or leaks into the wrong chamber

Question 27

What do these conditions all have in common:
Transposition of the great arteries
Tetralogy of fallot
Tricuspid atresia
Pulmonary atresia with intact ventricular septum
Total anomalous pulmonary venous connections
?

Answer 27

They are all congenital cyanotic heart disease

Question 28

How does cardiac failure present?

Answer 28

Usually seen with moderate/large LEFT TO RIGHT shunts, resulting in increased pulmonary flow and increased ventricular load, e.g: large VSD

Question 29

When does cardiac failure present?

Answer 29

Tends to present after a few weeks, as pulmonary pressure drops

Question 30

Clinical signs of cardiac failure?

Answer 30

Failure to thrive or gain weight
Slow/reduced feeding
Breathlessness (esp. when feeding)
Sweatiness, esp. on forehead
Hepatomegaly
Crepitations

Question 31

What is a VSD?

Answer 31

Defect/hole in the ventricular septum, causing left to right shunt (as pressure in right side has decreased) and turbulent flow