Paediatric Cardiology

Question 1

Innocent Murmurs (Flow Murmurs)

Answer 1

Innocent murmurs are also known as flow murmurs. They are very common in children. They are caused by fast blood flow through various areas of the heart during systole.

Innocent murmurs have typical features, all beginning with S:

Soft
Short
Systolic
Symptomless
Situation dependent, particularly if the murmur gets quieter with standing or only appears when the child is unwell or feverish
Clear innocent murmurs with no concerning features may not require any investigations. Features that would prompt further investigations and referral to a paediatric cardiologist would be:

Murmur louder than 2/6
Diastolic murmurs
Louder on standing
Other symptoms such as failure to thrive, feeding difficulty, cyanosis or shortness of breath

Question 2

Investigating murmurs

Answer 2

The key investigations to establish the cause of a murmur and rule out abnormalities in a child are:

ECG
Chest Xray
Echocardiography

Question 3

Pan-Systolic Murmurs

Answer 3

The differentials of a pan-systolic murmur and where they are heard loudest are:

Mitral regurgitation heard at the mitral area (fifth intercostal space, mid-clavicular line)
Tricuspid regurgitation heard at the tricuspid area (fifth intercostal space, left sternal border)
Ventricular septal defect heard at the left lower sternal border

Question 4

Ejection-Systolic Murmurs

Answer 4

The differentials of an ejection-systolic murmur and where they are heard loudest are:

Aortic stenosis heard at the aortic area (second intercostal space, right sternal border)
Pulmonary stenosis heard at the pulmonary area (second intercostal space, left sternal border)
Hypertrophic obstructive cardiomyopathy heart at the fourth intercostal space on the left sternal border

Question 5

Splitting of the Second Heart Sound

Answer 5

During inspiration the chest wall and diaphragm pull the lungs open. This also pulls the heart open. This is called negative intra-thoracic pressure. This causes the right side of the heart to fill faster as it pulls in blood from the venous system. The increased volume in the right ventricle causes it to take longer for the right ventricle to empty during systole, causing a delay in the pulmonary valve closing. When the pulmonary valve closes slightly later than the aortic valve, this causes the second heart sound to be “split”.

Question 6

Atrial Septal Defect

Answer 6

Atrial septal defects cause a mid-systolic, crescendo-decrescendo murmur loudest at the upper left sternal border, with a fixed split second heart sound. Splitting of the second heart sound can be normal with inspiration, however a “fixed split” second heart sound means the split does not change with inspiration and expiration. This occurs in an atrial septal defect because blood is flowing from the left atrium into the right atrium across the atrial septal defect, increasing the volume of blood that the right ventricle has to empty before the pulmonary valve can close. This doesn’t vary with respiration.

Question 7

Patent Ductus Arteriosus

Answer 7

A small patent ductus arteriosus may not cause any abnormal heart sounds. More significant PDAs cause a normal first heart sound with a continuous crescendo-decrescendo “machinery” murmur that may continue during the second heart sound, making the second heart sound difficult to hear.

Question 8

Tetralogy of Fallot

Answer 8

The murmur in tetralogy of Fallot arises from pulmonary stenosis, giving an ejection systolic murmur loudest at the pulmonary area (second intercostal space, left sternal border).

Question 9

Cyanotic Heart Disease

Answer 9

Cyanosis occurs when deoxygenated blood enters the systemic circulation. Cyanotic heart disease occurs when blood is able to bypass the pulmonary circulation and the lungs. This occurs across a right-to-left shunt. A right-to-left shunt describes any defect that allows blood to flow from the right side of the heart (the deoxygenated blood returning from the body) to the left side of the heart (the blood exiting the heart into the systemic circulation) without travelling through the lungs to get oxygenated.

Heart defects that can cause a right-to-left shunt, and therefore cyanotic heart disease, are:

Ventricular septal defect (VSD)
Atrial septal defect (ASD)
Patent ductus arteriosus (PDA)
Transposition of the great arteries
Patients with a VSD, ASD or PDA are usually not cyanotic. This is because the pressure in the left side of the heart is much greater than the right side, and blood will flow from the area of high pressure to the area of low pressure. This prevents a right-to-left shunt. If the pulmonary pressure increases beyond the systemic pressure blood will start to flow from right-to-left across the defect, causing cyanosis. This is called Eisenmenger syndrome.

Patients with transposition of the great arteries will always have cyanosis because the right side of the heart pumps blood directly into the aorta and systemic circulation.

Question 10

Patent ductus arteriosus

Answer 10

The ductus arteriosus normally stops functioning within 1-3 days of birth, and closes completely within the first 2-3 weeks of life. When it fails to close, this is called a “patent ductus arteriosus” (PDA). The reasons why it fails to close are unclear, but it may be genetic or related to maternal infections such as rubella. Prematurity is a key risk factor.

A small PDA can be asymptomatic, cause no functional problems and close spontaneously. Occasionally patients can remain asymptomatic throughout childhood and present in adulthood with signs of heart failure.

Question 11

Pathophysiology of patent ductus arteriosus

Answer 11

The pressure in the aorta is higher than that in the pulmonary vessels, so blood flows from the aorta to the pulmonary artery. This creates a left to right shunt where blood from the left side of the heart crosses to the circulation from the right side. This increases the pressure in the pulmonary vessels causing pulmonary hypertension, leading to right sided heart strain as the right ventricle struggles to contract against the increased resistance. Pulmonary hypertension and right sided heart strain lead to right ventricular hypertrophy. The increased blood flowing through the pulmonary vessels and returning to the left side of the heart leads to left ventricular hypertrophy.

Question 12

Presentation of patent ductus arteriosus

Answer 12

A patent ductus arteriosus can be picked up during the newborn examination if a murmur is heard. It may also present with symptoms of:

Shortness of breath
Difficulty feeding
Poor weight gain
Lower respiratory tract infections

Question 13

Patent ductus arteriosus murmur

Answer 13

A small patent ductus arteriosus may not have any abnormal heart sounds. More significant PDAs cause a normal first heart sound with a continuous crescendo-decrescendo “machinery” murmur that may continue during the second heart sound, making the second heart sound difficult to hear.

Question 14

Diagnosing patent ductus arteriosus

Answer 14

The diagnosis of PDA can be confirmed by echocardiogram. The use of doppler flow studies during the echo can assess the size and characteristics of the left to right shunt. An echo is also useful for assessing the effects of the PDA on the heart, for example demonstrating hypertrophy of the right ventricle, left ventricle or both.

Question 15

Managing patent ductus arteriosus

Answer 15

Patients are typically monitored until 1 year of age using echocardiograms. After 1 year of age it is highly unlikely that the PDA will close spontaneously and trans-catheter or surgical closure can be performed. Symptomatic patient or those with evidence of heart failure as a result of PDA are treated earlier.

Question 16

Pathophysiology of atrial septal defect

Answer 16

During the development of the fetus the left and right atria are connected. Two walls grow downwards from the top of the heart, then fuse together with the endocardial cushion in the middle of the heart to separate the atria. These two walls are called the septum primum and septum secondum.

Defects this these two walls lead to atrial septal defects, a hole connecting the left and right atria. There is a small hole in the septum secondum called the foramen ovale. The foramen ovale normally closes at birth.

An atrial septal defect leads to a shunt, with blood moving between the two atria. Blood moves from the left atrium to the right atrium because the pressure in the left atrium is higher than the pressure in the right atrium. This means blood continues to flow to the pulmonary vessels and lungs to get oxygenated and the patient does not become cyanotic, however the increased flow to the right side of the heart leads to right sided overload and right heart strain. This right sided overload can lead to right heart failure and pulmonary hypertension.

Eventually pulmonary hypertension can lead to Eisenmenger syndrome. This is where the pulmonary pressure is greater than the systemic pressure, the shunt reverses and forms a right to left shunt across the ASD, blood bypasses the lungs and the patient becomes cyanotic.

Question 17

Types of atrial septal defect

Answer 17

The types of atrial septal defect from most to least common are:

Ostium secondum, where the septum secondum fails to fully close, leaving a hole in the wall.
Patent foramen ovale, where the foramen ovale fails to close (although this not strictly classified as an ASD).
Ostium primum, where the septum primum fails to fully close, leaving a hole in the wall. This tends to lead to atrioventricular valve defects making it an atrioventricular septal defect.

Question 18

Complications of atrial septal defect

Answer 18

Stroke in the context of venous thromboembolism (see below)
Atrial fibrillation or atrial flutter
Pulmonary hypertension and right sided heart failure
Eisenmenger syndrome

TOM TIP: It is worth remembering atrial septal defects as a cause of stroke in patients with a DVT. Normally when patients have a DVT and this becomes an embolus, the clot travels to the right side of the heart, enters the lungs and becomes a pulmonary embolism. In patients with an ASD the clot is able to travel from the right atrium to the left atrium across the ASD. This means the clot can travel to the left ventricle, aorta and up to the brain, causing a large stroke. An exam question may feature a patient with a DVT that develops a large stroke and the challenge is to identify that they have had a lifelong asymptomatic ASD.

Question 19

Presentation of atrial septal defect

Answer 19

ASDs cause a mid-systolic, crescendo-decrescendo murmur loudest at the upper left sternal border with a fixed split second heart sound. Splitting of the second heart sound is where you hear the closure of the aortic and pulmonary valves at slightly different times. This can be normal with inspiration, however a “fixed split” second heart sound means the split does not change with inspiration or expiration. This occurs in an atrial septal defect because blood is flowing from the left atrium into the right atrium across the atrial septal defect, increasing the volume of blood that the right ventricle has to empty before the pulmonary valve can close. This doesn’t vary with respiration.

Atrial septal defects are often picked up through antenatal scans or newborn examinations. It may be asymptomatic in childhood and present in adulthood with dyspnoea, heart failure or stroke. Typical symptoms in childhood are:

Shortness of breath
Difficulty feeding
Poor weight gain
Lower respiratory tract infections
Interestingly, there is a possible link between migraine with aura and patent foramen ovale. Trials such as the PREMIUM trial found that treating the PFO did not have a significant effect on the migraines, and screening people with migraines for a PFO or treating a PFO to help migraines is not currently recommended.

Question 20

Managing atrial septal defect

Answer 20

Patients with an ASD should be referred to a paediatric cardiologist for ongoing management. If the ASD is small and asymptomatic, watching and waiting can be appropriate. ASDs can be corrected surgically using a transvenous catheter closure (via the femoral vein) or open heart surgery. Anticoagulants (such as aspirin, warfarin and NOACs) are used to reduce the risk of clots and stroke in adults.

Question 21

Ventricular septal defect

Answer 21

A ventricular septal defect (VSD) is a congenital hole in the septum (wall) between the two ventricles. This can vary in size from tiny to the entire septum, forming one large ventricle. VSDs can occur in isolation, however there is often an underlying genetic condition and they are commonly associated with Down’s Syndrome and Turner’s Syndrome.

Due to the increased pressure in the left ventricle compared to the right, blood typically flows from left the right through the hole. Blood is still flowing around the lungs before entering the rest of the body, therefore they remain acyanotic (not cyanotic) because their blood is properly oxygenated. A left to right shunt leads to right sided overload, right heart failure and increased flow into the pulmonary vessels.

The extra blood flowing through the right ventricle increases the pressure in the pulmonary vessels over time, causing pulmonary hypertension. If this continues, the pressure in the right side of the heart may become greater than the left, resulting in the blood being shunted from right to left and avoiding the lungs. When this happens the patient will become cyanotic because blood is bypassing the lungs. This is called Eisenmenger Syndrome.

Question 22

Presentation of ventricular septal defect

Answer 22

Often VSDs are initially symptomless and patients can present as late as adulthood. They may be picked up on antenatal scans or when a murmur is heard during the newborn baby check.

Typical symptoms include:

Poor feeding
Dyspnoea
Tachypnoea
Failure to thrive

Question 23

Examining ventricular septal defect

Answer 23

Patients with a VSD typically have a pan-systolic murmur more prominently heard at the left lower sternal border in the third and fourth intercostal spaces. There may be a systolic thrill on palpation.

TOMTIP: When you hear a pan-systolic murmur it is worth giving your top differential but also mention the other causes of this type of murmur. The causes of a pan-systolic murmur are ventricular septal defect, mitral regurgitation and tricuspid regurgitation.

Question 24

Treating ventricular septal defect

Answer 24

Treatment should be coordinated by a paediatric cardiologist. Small VSDs with no symptoms or evidence of pulmonary hypertension or heart failure can be watched over time. Often they close spontaneously.

VSDs can be corrected surgically using a transvenous catheter closure via the femoral vein or open heart surgery.

There is an increased risk of infective endocarditis in patients with a VSD. Antibiotic prophylaxis should be considered during surgical procedures to reduce the risk of developing infective endocarditis.

Question 25

Eisenmenger syndrome

Answer 25

Eisenmenger syndrome occurs when blood flows from the right side of the heart to the left across a structural heart lesion, bypassing the lungs. There are three underlying lesions that can result in Eisenmenger syndrome:

Atrial septal defect
Ventricular septal defect
Patent ductus arteriosus
Eisenmenger syndrome can develop after 1-2 years with large shunts or in adulthood with small shunts. It can develop more quickly during pregnancy, so women with a history of having a “hole in the heart” need an echo and close monitoring by a cardiologist during pregnancy.

Question 26

Pathophysiology of Eisenmenger syndrome

Answer 26

Normally when there is a septal defect blood will flow from the left side of the heart to the right. This is because the pressure in the left side is greater than in the right. Remember, the left ventricle has to pump blood through the entire body, whereas the right ventricle simply has to fill the lungs. A left to right shunt means blood still travels to the lungs and gets oxygenated, so the patient does not become cyanotic.

Over time the extra blood flowing into the right side of the heart and the lungs increases the pressure in the pulmonary vessels. This leads to pulmonary hypertension. When the pulmonary pressure exceeds the systemic pressure, blood begins to flow from the right side of the heart to the left across the septal defect. This is a right to left shunt. Essentially it becomes easier for the right side of the heart to pump blood across the defect into the left side of the heart compared with pumping blood into the lungs. This causes deoxygenated blood to bypass the lungs and enter the body. This causes cyanosis.

Cyanosis refers to the blue discolouration of skin relating to a low level of oxygen saturation in the blood. The bone marrow will respond to low oxygen saturations by producing more red blood cells and haemoglobin to increase the oxygen carrying capacity of the blood. This leads to polycythaemia, which is a high concentration of haemoglobin in the blood. Polycythaemia gives patients a plethoric complexion. A high concentration of red blood cells and haemoglobin make the blood more viscous, making patients more prone to developing blood clots.

Question 27

Examination findings with Eisenmenger syndrome

Answer 27

Examination findings associated with pulmonary hypertension:

Right ventricular heave: the right ventricle contracts forcefully against increased pressure in the lungs
Loud P2: loud second heart sound due to forceful shutting of the pulmonary valve
Raised JVP
Peripheral oedema
Examination findings related to the underlying septal defect:

Atrial septal defect: mid-systolic, crescendo-decrescendo murmur loudest at the upper left sternal border
Ventricular septal defect: pan-systolic murmur loudest at the left lower sternal border
Patent ductus arteriosus: continuous crescendo-decrescendo “machinery” murmur
Arrhythmias
Findings related to the right to left shunt and chronic hypoxia:

Cyanosis
Clubbing
Dyspnoea
Plethoric complexion (a red complexion related to polycythaemia)

Question 28

Prognosis of Eisenmenger syndrome

Answer 28

Eisenmenger syndrome reduces life expectancy by around 20 years compared with healthy individuals. The main causes of death are heart failure, infection, thromboembolism and haemorrhage. The mortality can be up to 50% in pregnancy.

Question 29

Managing Eisenmenger syndrome

Answer 29

Ideally the underlying defect should be managed optimally or corrected surgically to prevent the development of Eisenmenger syndrome.

Once the pulmonary pressure is high enough to cause the syndrome, it is not possible to medically reverse the condition. The only definitive treatment is a heart-lung transplant, however this has a high mortality.

Patients with Eisenmenger syndrome will be closely followed up by a specialist. Medical management involves:

Oxygen can help manage symptoms but does not affect overall outcomes
Treatment of pulmonary hypertension, for example using sildenafil
Treatment of arrhythmias
Treatment of polycythaemia with venesection
Prevention and treatment of thrombosis with anticoagulation
Prevention of infective endocarditis using prophylactic antibiotics

Question 30

Coarctation of the aorta

Answer 30

Coarctation of the aorta is a congenital condition where there is narrowing of the aortic arch, usually around the ductus arteriosus. The severity of the coarctation (or narrowing) can vary from mild to severe. It is often associated with an underlying genetic condition, particularly Turners syndrome.

Narrowing of the aorta reduces the pressure of blood flowing to the arteries that are distal to the narrowing. It increases the pressure in areas proximal to the narrowing, such as the heart and the first three branches of the aorta.

Question 31

Presentation of coarctation of the aorta

Answer 31

Often the only indication of coarctation in a neonate may be weak femoral pulses. Performing a four limb blood pressure will reveal high blood pressure in the limbs supplied from arteries that come before the narrowing, and lower blood pressure in limbs that come after the narrowing. There may be a systolic murmur heard below the left clavicle (left infraclavicular area) and below the left scapula. Coarctation may have other signs in infancy:

Tachypnoea and increased work of breathing
Poor feeding
Grey and floppy baby
Additional signs may develop over time:

Left ventricular heave due to left ventricular hypertrophy
Underdeveloped left arm where there is reduced flow to the left subclavian artery
Underdevelopment of the legs

Question 32

Managing coarctation of the aorta

Answer 32

The severity of the coarctation varies between patients. In mild cases patients can live symptom free until adulthood without requiring surgical input, and in severe cases patients will require emergency surgery shortly after birth.

In cases of critical coarctation where there is a risk of heart failure and death shortly after birth Prostaglandin E is used keep the ductus arteriosus open while waiting for surgery. This allows some blood flow flow through the ductus arteriosus into the systemic circulation distal to the coarctation. Surgery is then performed to correct the coarctation and to ligate the ductus arteriosus.

Question 33

Congenital aortic stenosis

Answer 33

Patients with congenital aortic valve stenosis are born with a narrow aortic valve that restricts blood flow from the left ventricle into the aorta. The severity of the stenosis varies between patients and will determine the symptoms.

The aortic valve is normally made up of three leaflets, called the aortic sinuses of Valsalva, which allow blood to flow from the left ventricle into the aorta, but prevent blood from flowing back into the left ventricle. Patients with aortic stenosis may have one, two, three or four leaflets.

Question 34

Presentation of congenital aortic stenosis

Answer 34

Mild aortic stenosis can be completely asymptomatic, discovered as an incidental murmur during a routine examination. More significant aortic stenosis can present with symptoms of fatigue, shortness of breath, dizziness and fainting. Symptoms are typically worse on exertion as the outflow from the left ventricle cannot keep up with demand. Severe aortic stenosis will present with heart failure within months of birth.

Question 35

Signs of congenital aortic stenosis

Answer 35

The key examination finding is an ejection systolic murmur heard loudest at the aortic area, which is the second intercostal space, right sternal border. It has a crescendo-decrescendo character and radiates to the carotids.

Other signs that may be present on examination are:

Ejection click just before the murmur
Palpable thrill during systole
Slow rising pulse and narrow pulse pressure

Question 36

Managing congenital aortic stenosis

Answer 36

The gold standard investigation for establishing a diagnosis is an echocardiogram.

Congenital aortic stenosis tends to be a progressive condition that worsens over time. Patients need regular follow-up under a paediatric cardiologist, with echocardiograms, ECGs and exercise testing to monitor the progression of the condition. Patient with more significant stenosis may need to restrict physical activities.

Options for treating the stenosis are:

Percutaneous balloon aortic valvoplasty
Surgical aortic valvotomy
Valve replacement

Question 37

Complications of congenital aortic stenosis

Answer 37

Left ventricular outflow tract obstruction
Heart failure
Ventricular arrhythmia
Bacterial endocarditis
Sudden death, often on exertion

Question 38

Congenital pulmonary valve stenosis

Answer 38

The pulmonary valve usually consists of three leaflets that open and close to let blood out and prevent blood from returning to the heart. These leaflets can develop abnormally, becoming thickened or fused. This results in a narrow opening between the right ventricle and the pulmonary artery. This is called congenital pulmonary valve stenosis.

Question 39

Associations of congenital pulmonary stenosis

Answer 39

Congenital pulmonary valve stenosis often occurs without any associations. It can be associated with other conditions such as:

Tetralogy of Fallot
William syndrome
Noonan syndrome
Congenital rubella syndrome

Question 40

Presentation of congenital pulmonary stenosis

Answer 40

Often pulmonary stenosis is completely asymptomatic, and it is discovered as an incidental finding of a murmur during routine baby checks. More significant pulmonary valve stenosis can present with symptoms of fatigue on exertion, shortness of breath, dizziness and fainting.

Question 41

Signs of congenital pulmonary stenosis

Answer 41

Ejection systolic murmur heard loudest at the pulmonary area (second intercostal space, left sternal border)
Palpable thrill in the pulmonary area
Right ventricular heave due to right ventricular hypertrophy
Raised JVP with giant a waves

Question 42

Managing congenital pulmonary stenosis

Answer 42

The gold standard investigation for establishing a diagnosis is an echocardiogram.

In mild pulmonary stenosis without symptoms patients generally do not require any intervention. They are followed up by a cardiologist with a “watching and waiting” approach.

If the patient is symptomatic or the valve is more significantly stenosed, balloon valvuloplasty via a venous catheter is the treatment of choice. This involves inserting a catheter under xray guidance into the femoral vein, through the inferior vena cava and right side of the heart to the pulmonary valve, and dilating the valve by inflating a balloon. If valvuloplasty is not appropriate or fails open-heart surgery can be performed.

Question 43

Tetralogy of Fallot

Answer 43

Tetralogy of Fallot is a congenital condition where there are four coexisting pathologies:

Ventricular septal defect (VSD)
Overriding aorta
Pulmonary valve stenosis
Right ventricular hypertrophy

The VSD allows blood to flow between the ventricles. The term “overriding aorta” refers to the fact that the entrance to the aorta (the aortic valve) is placed further to the right than normal, above the VSD. This means that when the right ventricle contracts and sends blood upwards, the aorta is in the direction of travel of that blood, therefore a greater proportion of deoxygenated blood enters the aorta from the right side of the heart.

Stenosis of the pulmonary valve provides greater resistance against the flow of blood from the right ventricle. This encourages blood to flow through the VSD and into the aorta rather than taking the normal route into the pulmonary vessels. Therefore, the overriding aorta and pulmonary stenosis encourage blood to be shunted from the right heart to the left, causing cyanosis.

The increased strain on the muscular wall of the right ventricle as it attempts to pump blood against the resistance of the left ventricle and pulmonary stenosis causes right ventricular hypertrophy, with thickening of the heart muscle.

These cardiac abnormalities cause a right to left cardiac shunt. This means blood bypasses the child’s lungs. Blood bypassing the lungs does not become oxygenated. Deoxygenated blood entering the systemic circulation causes cyanosis. The degree to which this happens is related mostly to the severity of the patients pulmonary stenosis.

Question 44

Risk factors for Tetralogy of Fallot

Answer 44

Rubella infection
Increased age of the mother (over 40 years)
Alcohol consumption in pregnancy
Diabetic mother

Question 45

Investigating Tetralogy of Fallot

Answer 45

As with all structural congenital cardiac abnormalities, an echocardiogram is the investigation of choice for establishing the diagnosis. During the echocardiogram, the machine can produce coloured pictures that demonstrate the direction of flow of blood. This is called doppler flow studies. This is useful in assessing the severity of the abnormality and shunt.

A chest xray may show the characteristic “boot shaped” heart due to right ventricular thickening. This not particularly useful diagnostically except during medical exams.

Question 46

Presenting Tetralogy of Fallot

Answer 46

Most cases are picked up before the child is born during the antenatal scans. Additionally, an ejection systolic murmur caused by the pulmonary stenosis may be heard on the newborn baby check.

Severe cases will present with heart failure before one year of age. In milder cases, they can present as older children once they start to develop signs and symptoms of heart failure.

Question 47

Signs and symptoms of Tetralogy of Fallot

Answer 47

Cyanosis (blue discolouration of the skin due to low oxygen saturations)
Clubbing
Poor feeding
Poor weight gain
Ejection systolic murmur heard loudest in the pulmonary area (second intercostal space, left sternal border)
“Tet spells”

Question 48

Tet Spells

Answer 48

“Tet Spells” are intermittent symptomatic periods where the right to left shunt becomes temporarily worsened, precipitating a cyanotic episode. This happens when the pulmonary vascular resistance increases or the systemic resistance decreases. For example, if the child is physically exerting themselves they are generating a lot of carbon dioxide. Carbon dioxide is a vasodilator that causes systemic vasodilation and therefore reduces the systemic vascular resistance. Blood flow will choose the path of least resistance, so blood will be pumped from the right ventricle to the aorta rather than the pulmonary vessels, bypassing the lungs.

These episodes may be precipitated by waking, physical exertion or crying. The child will become irritable, cyanotic and short of breath. Severe spells can lead to reduced consciousness, seizures and potentially death.

Question 49

Tet Spell Treatment Options

Answer 49

Older children may squat when a tet spell occurs. Younger children can be positioned with their knees to their chest. Squatting increases the systemic vascular resistance. This encourages blood to enter the pulmonary vessels.

Any medical management of a tet spell should involve an experienced paediatrician, as they can be potentially life threatening.

Supplementary oxygen is essential in hypoxic children as hypoxia can be fatal.
Beta blockers can relax the right ventricle and improve flow to the pulmonary vessels.
IV fluids can increase pre-load, increasing the volume of blood flowing to the pulmonary vessels.
Morphine can decrease respiratory drive, resulting in more effective breathing.
Sodium bicarbonate can buffer any metabolic acidosis that occurs.
Phenylephrine infusion can increase systemic vascular resistance.

Question 50

Management and prognosis of Tetralogy of Fallot

Answer 50

In neonates, a prostaglandin infusion can be used to maintain the ductus arteriosus. This allows blood to flow from the aorta back to the pulmonary arteries.

Total surgical repair by open heart surgery is the definitive treatment, however mortality from surgery is around 5%.

Prognosis depends on the severity, however it is poor without treatment. With corrective surgery, 90% of patients will live into adulthood.

Question 51

Ebstein’s anomaly

Answer 51

Ebstein’s anomaly is a congenital heart condition where the tricuspid valve is set lower in the right side of the heart (towards the apex), causing a bigger right atrium and a smaller right ventricle. This leads to poor flow from the right atrium to the right ventricle, and therefore poor flow to the pulmonary vessels. It is often associated with a right to left shunt across the atria via an atrial septal defect. When this happens blood bypasses the lungs, leading to cyanosis. It is also associated with Wolff-Parkinson-White syndrome.

Question 52

Diagnosing Ebstein’s anomaly

Answer 52

Echocardiogram is the investigation of choice for confirming the diagnosis and assessing the severity.

Question 52

Presentation of Ebstein’s anomaly

Answer 52

Typical presenting features include:

Evidence of heart failure (e.g. oedema)
Gallop rhythm heard on auscultation characterised by the addition of the third and fourth heart sounds
Cyanosis
Shortness of breath and tachypnoea
Poor feeding
Collapse or cardiac arrest
Symptoms in patients with an associated atrial septal defect often present a few days after birth, when the ductus arteriosus closes. Where there is a right to left shunt across an atrial septal defect the ductus arteriosus allows blood to flow from the aorta into the pulmonary vessels to get oxygenated. This minimises the cyanosis. When the duct closes the patient becomes cyanotic and symptomatic.

Question 53

Managing Ebstein’s anomaly

Answer 53

Medical management includes treating arrhythmias and heart failure. Prophylactic antibiotics may be used to prevent infective endocarditis. Definitive management is by surgical correction of the underlying defect.

Question 54

Transposition of the great arteries

Answer 54

Transposition of the great arteries is a condition where the attachments of the aorta and the pulmonary trunk to the heart are swapped (“transposed”). This means the right ventricle pumps blood into the aorta and the left ventricle pumps blood into the pulmonary vessels. In this scenario are two separate circulations that don’t mix: one travelling through the systemic system and right side of the heart and the other traveling through the pulmonary system and left side of the heart.

The condition can also be associated with:

Ventricular septal defect
Coarctation of the aorta
Pulmonary stenosis
During pregnancy there is normal development of the fetus. The gas and nutrient exchange happens in the placenta, therefore it is not necessary for blood to flow to the lungs. After birth the condition is immediately life threatening as there is no connection between the systemic circulation and the pulmonary circulation. The baby will be cyanosed.

Immediate survival depends on a shunt between the systemic circulation and pulmonary circulation that allows blood flowing through the body an opportunity to get oxygenated in the lungs. This shunt can occur across a patent ductus arteriosus, atrial septal defect or ventricular septal defect.

Question 55

Presentation of transposition of the great arteries

Answer 55

The defect is often diagnosed during pregnancy with antenatal ultrasound scans. Close monitoring is necessary during the pregnancy and arrangements should be made so that the woman gives birth in a hospital capable of managing the condition after birth.

Where the defect was not detected during pregnancy it will present with cyanosis at or within a few days of birth. A patent ductus arteriosus or ventricular septal defect can initially compensate by allowing blood to mix between the systemic circulation and the lungs, however within a few weeks of life they will develop respiratory distress, tachycardia, poor feeding, poor weight gain and sweating.

Question 56

Managing transposition of the great arteries

Answer 56

Where there is a ventricular septal defect, this will allow some mixing of blood between the two systems and provide some time for definitive treatment.

A prostaglandin infusion can be used to maintain the ductus arteriosus. This allows blood from the aorta to flow to the pulmonary arteries for oxygenation.

Balloon septostomy involves inserting a catheter into the foramen ovale via the umbilicus, and inflating a balloon to create a large atrial septal defect. This allows blood returning from the lungs (on the left side) to flow to the right side of the heart and out through the aorta to the body.

Open heart surgery is the definitive management. A cardiopulmonary bypass machine is used to perform an “arterial switch” procedure within a few days of birth. If present, a VSD or ASD can be corrected at the same time.