• Lesions are being increasingly identified on antenatal ultrasound screening

• Most lesions are diagnosed by echocardiography, the mainstay of diagnostic imaging

• MRI allows three-dimensional reconstruction of complex cardiac disorders, assessment of haemodynamics and flow patterns and assists interventional cardiology, reducing the need for cardiac catheterisation

• Most defects can be corrected by definitive surgery at the initial operation

• An increasing number of defects (60%) are treated non-invasively, e.g. persistent ductus arteriosus

• New therapies are available to treat pulmonary hypertension and delay transplantation

• The overall infant cardiac surgical mortality has been reduced from approximately 20% in 1970 to 2% in 2010.

Epidemiology

Heart disease in children is mostly congenital. It is the most common single group of structural malformations in infants:

The nine most common anomalies account for 80% of all lesions (Box 17.1), but:

Aetiology

Genetic causes are increasingly recognised in the aetiology of congenital heart disease, now in more than 10%. These might affect whole chromosomes, point mutations or microdeletions (Table 17.1). Polygenic abnormalities probably explain why having a child with congenital heart disease doubles the risk for subsequent children and the risk is higher still if either parent has congenital heart disease. A small proportion are related to external teratogens.

Circulatory changes at birth

In the fetus, the left atrial pressure is low, as relatively little blood returns from the lungs. The pressure in the right atrium is higher than in the left, as it receives all the systemic venous return including blood from the placenta. The flap valve of the foramen ovale is held open, blood flows across the atrial septum into the left atrium and then into the left ventricle, which in turn pumps it to the upper body (Fig. 17.1).

With the first breaths, resistance to pulmonary blood flow falls and the volume of blood flowing through the lungs increases six-fold. This results in a rise in the left atrial pressure. Meanwhile, the volume of blood returning to the right atrium falls as the placenta is excluded from the circulation. The change in the pressure difference causes the flap valve of the foramen ovale to be closed. The ductus arteriosus, which connects the pulmonary artery to the aorta in fetal life, will normally close within the first few hours or days. Some babies with congenital heart lesions rely on blood flow through the duct (duct-dependent circulation). Their clinical condition will deteriorate dramatically when the duct closes, which is usually at 1–2 days of age but occasionally later.

Presentation

Congenital heart disease presents with:

Heart failure

Symptoms

• Breathlessness (particularly on feeding or exertion)

• Sweating

• Poor feeding

• Recurrent chest infections.

Signs

• Poor weight gain or ‘faltering growth’

• Tachypnoea

• Tachycardia

• Heart murmur, gallop rhythm

• Enlarged heart

• Hepatomegaly

• Cool peripheries.

Signs of right heart failure (ankle oedema, sacral oedema and ascites) are rare in developed countries, but may be seen with long-standing rheumatic fever or pulmonary hypertension, with tricuspid regurgitation and right atrial dilatation.

In the first week of life, heart failure (Box 17.2) usually results from left heart obstruction, e.g. coarctation of the aorta. If the obstructive lesion is very severe then arterial perfusion may be predominantly by right-to-left flow of blood via the arterial duct, so-called duct-dependent systemic circulation (Fig. 17.2). Closure of the duct under these circumstances rapidly leads to severe acidosis, collapse and death unless ductal patency is restored (Case History 17.1).

Box 17.2   Causes of heart failure

1 Neonates – obstructed (duct-dependent) systemic circulation

• Hypoplastic left heart syndrome

• Critical aortic valve stenosis

• Severe coarctation of the aorta

• Interruption of the aortic arch

2 Infants (high pulmonary blood flow)

• Ventricular septal defect

• Atrioventricular septal defect

• Large persistent ductus arteriosus

3 Older children and adolescents (right or left heart failure)

• Eisenmenger syndrome (right heart failure only)

• Rheumatic heart disease

• Cardiomyopathy.

After the first week of life, progressive heart failure is most likely due to a left-to-right shunt (Case History 17.2). During the subsequent weeks, as the pulmonary vascular resistance falls, there is a progressive increase in left-to-right shunt and increasing pulmonary blood flow. This causes pulmonary oedema and breathlessness.

Such symptoms of heart failure will increase up to the age of about 3 months, but may subsequently improve as the pulmonary vascular resistance rises in response to the left-to-right shunt. If left untreated, these children will develop Eisenmenger syndrome, which is irreversibly raised pulmonary vascular resistance resulting from chronically raised pulmonary arterial pressure and flow. Now the shunt is from right to left and the teenager is blue. If this develops, the only surgical option is a heart-lung transplant, if available, although medication is now available to palliate the symptoms.

Cyanosis

• Peripheral cyanosis (blueness of the hands and feet) may occur when a child is cold or unwell from any cause or with polycythaemia

• Central cyanosis, seen on the tongue as a slate blue colour, is associated with a fall in arterial blood oxygen tension. It can only be recognised clinically if the concentration of reduced haemoglobin in the blood exceeds 5 g/dl, so it is less pronounced if the child is anaemic

• Check with a pulse oximeter that an infant’s oxygen saturation is normal (≥94%). Persistent cyanosis in an otherwise well infant is nearly always a sign of structural heart disease.

Cyanosis in a newborn infant with respiratory distress (respiratory rate >60 breaths/min) may be due to:

• Cardiac disorders – cyanotic congenital heart disease

• Respiratory disorders, e.g. surfactant deficiency, meconium aspiration, pulmonary hypoplasia, etc.

• Persistent pulmonary hypertension of the newborn (PPHN) – failure of the pulmonary vascular resistance to fall after birth

• Infection – septicaemia from group B streptococcus and other organisms

• Metabolic disease – metabolic acidosis and shock.

Case History

17.1 Shock

A 2-day-old baby had been discharged home the day after delivery following a normal routine examination. He suddenly collapsed and was rushed to hospital. He was pale, with grey lips. The right brachial pulse could just be felt, the femoral pulses were impalpable and his liver was significantly enlarged. Blood gases showed a severe metabolic acidosis. The differential diagnosis was:

• Congenital heart disease

• Septicaemia

• Inherited disorder of metabolism.

He was ventilated and treated with volume support. Blood cultures were taken and antibiotics started for possible sepsis. Blood and urine samples were taken for an amino acid screen and urine for organic acids. As the femoral pulses remained impalpable, a prostaglandin infusion was started. Within 2 hours, he was pink and well perfused and the acidosis was resolving. Severe coarctation of the aorta (Fig. 17.3) was diagnosed on echocardiography. He had developed shock from a left heart outflow tract obstruction once the arterial duct had closed.

Maintaining ductal patency is the key to early survival in neonates with a duct-dependent circulation.

Case History

17.2 Heart failure

A 5-week-old female infant was referred to hospital because of wheezing, poor feeding and poor weight gain during the previous 2 weeks. Before this, she had been well. Her routine neonatal examination had been normal. She was tachypnoeic (50–60 breaths/min) and there was some sternal and intercostal recession. The pulses were normal. There was a thrill, a pansystolic murmur at the lower left sternal edge and a slightly accentuated pulmonary component to the second heart sound. There were scattered wheezes. The liver was enlarged, palpable at two fingerbreadths below the costal margin. The ECG was unremarkable. The chest radiograph showed cardiomegaly and increased pulmonary vascular markings. An echocardiogram showed a moderate-sized ventricular septal defect (VSD) (Fig. 17.4). Treatment was medical with diuretics and captopril. The VSD closed spontaneously at 18 months.

This infant developed heart failure from a moderate VSD presenting at several weeks of age when the pulmonary resistance fell, causing increased left-to-right shunting of blood. The defect closed spontaneously.

Summary

Presentation of congenital heart disease

• Antenatal ultrasound screening – increasing proportion detected

• Detection of a heart murmur – need to differentiate innocent from pathological murmur

• Cyanosis – if duct dependent, prostaglandin to maintain ductal patency is vital for initial survival

• Heart failure – usually from left-to-right shunt when pulmonary vascular resistance falls

• Shock – when duct closes in severe left heart obstruction.

Whether the presentation of congenital heart disease is with a heart murmur, heart failure, cyanosis or shock depends on the underlying anatomic lesion causing:

• left to right shunt

• right to left shunt

• common mixing

• outflow obstruction in the well or sick child.

This is summarised in Table 17.2.

Table 17.2

Types of presentation with congenital heart disease

Type of lesion	Left-to-right shunt	Right-to-left shunt	Common mixing	Well children with obstruction	Sick neonates with obstruction
Symptoms	Breathless or asymptomatic	Blue	Breathless and blue	Asymptomatic	Collapsed with shock
Examples	ASD	Tetralogy of Fallot	AVSD	AS	Coarctation
	VSD	TGA	Complex congenital heart disease	PS	HLHS
	PDA			Adult-type CoA

ASD, atrial septal defect; VSD, ventricular septal defect; PDA, patent ductus arteriosus; TGA, transposition of the great arteries; AVSD, atrioventricular; AS, aortic stenosis; PS, pulmonary stenosis; CoA, coarctation of the aorta; HLHS, hypoplastic left heart syndrome.

Diagnosis

If congenital heart disease is suspected, a chest radiograph and ECG (Box 17.3) should be performed. Although rarely diagnostic, they may be helpful in establishing that there is an abnormality of the cardiovascular system and as a baseline for assessing future changes. Echocardiography, combined with Doppler ultrasound, enables almost all causes of congenital heart disease to be diagnosed. Even when a paediatric cardiologist is not available locally a specialist echocardiography opinion may be available via telemedicine, or else transfer to the cardiac centre will be necessary. A specialist opinion is required if the child is haemodynamically unstable, if there is heart failure, if there is cyanosis, when the oxygen saturations are <94% due to heart disease and when there are reduced volume pulses.

Nomenclature

The European (as opposed to American) system for naming congenital heart disease is referred to as sequential segmental arrangement. The advantage is that it is not necessary to remember the pattern of an eponymous syndrome, e.g. tetralogy of Fallot. The disadvantage is that it is longwinded. The idea is that each component is described in turn, naming the way the atria, then the ventricles and then the great arteries are connected. Hence, a normal heart will be described as situs solitus (i.e. the atria are in the correct orientation), concordant atrioventricular connection and concordant ventriculo–arterial connection. Therefore a heart of any complexity can be described in a logical step-by-step process. This system is not described here, as it is beyond the scope of this book.

Left-to-right shunts

These are:

Atrial septal defect

There are two main types of atrial septal defect (ASD):

• Secundum ASD (80% of ASDs) (Fig. 17.5a)

• Partial atrioventricular septal defect (primum ASD, pAVSD) (Fig 17.5b).

Both present with similar symptoms and signs, but their anatomy is quite different. The secundum ASD is a defect in the centre of the atrial septum involving the foramen ovale.

Partial AVSD is a defect of the atrioventricular septum and is characterised by:

• An inter-atrial communication between the bottom end of the atrial septum and the atrioventricular valves (primum ASD)

• Abnormal atrioventricular valves, with a left atrioventricular valve which has three leaflets and tends to leak (regurgitant valve).

Clinical features

Symptoms

• None (commonly)

• Recurrent chest infections/wheeze

• Arrhythmias (fourth decade onwards).

Physical signs (Fig. 17.5c)

• An ejection systolic murmur best heard at the upper left sternal edge – due to increased flow across the pulmonary valve because of the left-to-right shunt

• A fixed and widely split second heart sound (often difficult to hear) – due to the right ventricular stroke volume being equal in both inspiration and expiration

• With a partial AVSD, an apical pansystolic murmur from atrioventricular valve regurgitation.

Atrial septal defect

Investigations

Chest radiograph (Fig. 17.5d)

Cardiomegaly, enlarged pulmonary arteries and increased pulmonary vascular markings.

ECG

• Secundum ASD – partial right bundle branch block is common (but may occur in normal children), right axis deviation due to right ventricular enlargement (Fig. 17.5e)

• Partial AVSD – a ‘superior’ QRS axis (mainly negative in AVF) (Fig 17.5f). This occurs because there is a defect of the middle part of the heart where the atrioventricular node is. The displaced node then conducts to the ventricles superiorly, giving the abnormal axis.

Echocardiography

This will delineate the anatomy and is the mainstay of diagnostic investigations.

Management

Children with significant atrial septal defect (large enough to cause right ventricle dilation) will require treatment. For secundum ASDs, this is by cardiac catheterisation with insertion of an occlusion device (Fig 17.5g), but for partial AVSD, surgical correction is required. Treatment is usually undertaken at about 3–5 years of age in order to prevent right heart failure and arrhythmias in later life.

Ventricular septal defects

Ventricular septal defects (VSDs) are common, accounting for 30% of all cases of congenital heart disease. There is a defect anywhere in the ventricular septum, perimembranous (adjacent to the tricuspid valve) or muscular (completely surrounded by muscle). They can most conveniently be considered according to the size of the lesion.

Small VSDs

These are smaller than the aortic valve in diameter, perhaps up to 3 mm.

Clinical features

Symptoms

• Asymptomatic.

Physical signs

• Loud pansystolic murmur at lower left sternal edge (loud murmur implies smaller defect)

• Quiet pulmonary second sound (P₂).

Investigations

Chest radiograph

• Normal.

ECG

• Normal.

Echocardiography

• Demonstrates the precise anatomy of the defect. It is possible to assess its haemodynamic effects using Doppler echocardiography. There is no pulmonary hypertension.

Management

These lesions will close spontaneously. This is ascertained by the disappearance of the murmur with a normal ECG on follow-up by a paediatrician or paediatric cardiologist and by a normal echocardiogram. While the VSD is present, prevention of bacterial endocarditis is by maintaining good dental hygiene.

Large ventricular septal defect

Large VSDs

These defects are the same size or bigger than the aortic valve (Fig. 17.6a).

Clinical features

Symptoms

• Heart failure with breathlessness and failure to thrive (faltering growth) after 1 week old

• Recurrent chest infections.

Physical signs (Fig. 17.6b)

• Tachypnoea, tachycardia and enlarged liver from heart failure

• Active precordium

• Soft pansystolic murmur or no murmur (implying large defect)

• Apical mid-diastolic murmur (from increased flow across the mitral valve after the blood has circulated through the lungs)

• Loud pulmonary second sound (P₂) – from raised pulmonary arterial pressure.

Investigations

Chest radiograph (Fig. 17.6c)

• Cardiomegaly

• Enlarged pulmonary arteries

• Increased pulmonary vascular markings

• Pulmonary oedema.

ECG (Fig. 17.6d)

• Biventricular hypertrophy by 2 months of age.

Echocardiography

• Demonstrates the anatomy of the defect, haemodynamic effects and pulmonary hypertension (due to high flow).

Management

Drug therapy for heart failure is with diuretics, often combined with captopril. Additional calorie input is required. There is always pulmonary hypertension in children with large VSD and left-to-right shunt. This will ultimately lead to irreversible damage of the pulmonary capillary vascular bed (see Eisenmenger syndrome, below). To prevent this, surgery is usually performed at 3–6 months of age in order to:

• Manage heart failure and failure to thrive

• Prevent permanent lung damage from pulmonary hypertension and high blood flow.

Persistent ductus arteriosus (PDA, persistent arterial duct)

The ductus arteriosus connects the pulmonary artery to the descending aorta. In term infants, it normally closes shortly after birth. In persistent ductus arteriosus it has failed to close by 1 month after the expected date of delivery due to a defect in the constrictor mechanism of the duct. The flow of blood across a persistent ductus arteriosus (PDA) is then from the aorta to the pulmonary artery (i.e. left to right), following the fall in pulmonary vascular resistance after birth. In the pre-term infant, the presence of a persistent ductus arteriosus is not from congenital heart disease but due to prematurity. This is described in Chapter 9.

Clinical features

Most children present with a continuous murmur beneath the left clavicle (Fig. 17.7a). The murmur continues into diastole because the pressure in the pulmonary artery is lower than that in the aorta throughout the cardiac cycle. The pulse pressure is increased, causing a collapsing or bounding pulse. Symptoms are unusual, but when the duct is large there will be increased pulmonary blood flow with heart failure and pulmonary hypertension.

Investigations

The chest radiograph and ECG are usually normal, but if the PDA is large and symptomatic the features on chest radiograph (Fig. 17.7b) and ECG (Fig. 17.7c) are indistinguishable from those seen in a patient with a large VSD. However, the duct is readily identified on echocardiography.

Management

Closure is recommended to abolish the lifelong risk of bacterial endocarditis and of pulmonary vascular disease. Closure is with a coil or occlusion device introduced via a cardiac catheter at about 1 year of age (Fig. 17.7d–f). Occasionally, surgical ligation is required.

Summary

Left-to-right shunts

Lesion	Symptoms	Signs	Management
ASD
Secundum	None	ESM at ULSE	Catheter device closure at 3–5 years
		Fixed split S2
Partial AVSD	None	ESM at ULSE	Surgery at 3 years
		Fixed split S2
		Pansystolic murmur at apex
VSD
Small (80–90% of cases)	None	Pansystolic murmur at LLSE	None
Large (10–20% if cases)	Heart failure	Active precordium, loud P2, soft murmur, tachypnoea, hepatomegaly	Diuretics, captopril, calories
			Surgery at 3–6 months old
PDA	None	Continuous murmur at ULSE ± bounding pulses	Coil or device closure at cardiac catheter at 1 year, or ligation

ASD, atrial septal defect; AVSD, atrioventricular septal defect; VSD, ventricular septal defect; PDA, persistent ductus arteriosus; ESM, ejection systolic murmur; ULSE, upper left sternal edge; LLSE, lower left sternal edge.

Persistent ductus arteriosus

Right-to-left shunts

These are:

Presentation is with cyanosis (blue, oxygen saturations ≤94% or collapsed), usually in the first week of life.

Tetralogy of Fallot

This is the most common cause of cyanotic congenital heart disease (Fig. 17.8a).

Tetralogy of Fallot

Clinical features

In tetralogy of Fallot, as implied by the name, there are four cardinal anatomical features:

• A large VSD

• Overriding of the aorta with respect to the ventricular septum

• Subpulmonary stenosis causing right ventricular outflow tract obstruction

• Right ventricular hypertrophy as a result.

Symptoms

Most are diagnosed:

• antenatally or

• following the identification of a murmur in the first 2 months of life. Cyanosis at this stage may not be obvious, although a few present with severe cyanosis in the first few days of life.

The classical description of severe cyanosis, hypercyanotic spells and squatting on exercise, developing in late infancy, is now rare in developed countries, but still common where access to the necessary paediatric cardiac services is not available. However, it is important to recognise hypercyanotic spells, as they may lead to myocardial infarction, cerebrovascular accidents and even death if left untreated. They are characterised by a rapid increase in cyanosis, usually associated with irritability or inconsolable crying because of severe hypoxia, and breathlessness and pallor because of tissue acidosis. On auscultation, there is a very short murmur during a spell.

Signs

• Clubbing of the fingers and toes will develop in older children

• A loud harsh ejection systolic murmur at the left sternal edge from day 1 of life (Fig. 17.8b). With increasing right ventricular outflow tract obstruction, which is predominantly muscular and below the pulmonary valve, the murmur will shorten and cyanosis will increase.

Investigations

Chest radiograph (Fig. 17.8c)

A radiograph will show a relatively small heart, possibly with an uptilted apex (boot-shaped) due to right ventricular hypertrophy, more prominent in the older child. There may be a right-sided aortic arch, but characteristically, there is a pulmonary artery ‘bay’, a concavity on the left heart border where the convex-shaped main pulmonary artery and right ventricular outflow tract would normally be profiled. There may also be decreased pulmonary vascular markings reflecting reduced pulmonary blood flow.

ECG (Fig. 17.8d)

Normal at birth. Right ventricular hypertrophy when older.

Echocardiography

This will demonstrate the cardinal features, but cardiac catheterisation may be required to show the detailed anatomy of the coronary arteries.

Management

• Initial management is medical, with definitive surgery at around 6 months of age. It involves closing the VSD and relieving right ventricular outflow tract obstruction, sometimes with an artificial patch, which extends across the pulmonary valve.

• Infants who are very cyanosed in the neonatal period require a shunt to increase pulmonary blood flow. This is usually done by surgical placement of an artificial tube between the subclavian artery and the pulmonary artery (a modified Blalock–Taussig shunt), or sometimes by balloon dilatation of the right ventricular outflow tract.

• Hypercyanotic spells are usually self-limiting and followed by a period of sleep. If prolonged (beyond about 15 min), they require prompt treatment with:

– sedation and pain relief (morphine is excellent)

– intravenous propranolol (or an α adrenoceptor agonist), which probably works both as a peripheral vasoconstrictor and by relieving the subpulmonary muscular obstruction that is the cause of reduced pulmonary blood flow

– intravenous volume administration

– bicarbonate to correct acidosis

– muscle paralysis and artificial ventilation in order to reduce metabolic oxygen demand.

Transposition of the great arteries

The aorta is connected to the right ventricle, and the pulmonary artery is connected to the left ventricle (discordant ventriculo–arterial connection). The blue blood is therefore returned to the body and the pink blood is returned to the lungs (Fig. 17.9a). There are two parallel circulations – unless there is mixing of blood between them this condition is incompatible with life. Fortunately, there are a number of naturally occurring associated anomalies, e.g. VSD, ASD and PDA, as well as therapeutic interventions which can achieve this mixing in the short term.

Clinical features

Symptoms

Cyanosis is the predominant symptom. It may be profound and life-threatening. Presentation is usually on day 2 of life when ductal closure leads to a marked reduction in mixing of the desaturated and saturated blood. Cyanosis will be less severe and presentation delayed if there is more mixing of blood from associated anomalies, e.g. an ASD.

Physical signs (Fig. 17.9b)

• Cyanosis is always present

• The second heart sound is often loud and single

• Usually no murmur, but may be a systolic murmur from increased flow or stenosis within the left ventricular (pulmonary) outflow tract.

Investigations

Chest radiograph (Fig. 17.9c)

This may reveal the classic findings of a narrow upper mediastinum with an ‘egg on side’ appearance of the cardiac shadow (due to the anteroposterior relationship of the great vessels, narrow vascular pedicle and hypertrophied right ventricle, respectively). Increased pulmonary vascular markings are common due to increased pulmonary blood flow.

ECG (Fig. 17.9d)

This is usually normal.

Echocardiography

This is essential to demonstrate the abnormal arterial connections and associated abnormalities.

Management

• In the sick cyanosed neonate, the key is to improve mixing.

• Maintaining the patency of the ductus arteriosus with a prostaglandin infusion is mandatory.

• A balloon atrial septostomy may be a life-saving procedure which may need to be performed in 20% of those with transposition of the great arteries (Fig. 17.9e–g). A catheter, with an inflatable balloon at its tip, is passed through the umbilical or femoral vein and then on through the right atrium and foramen ovale. The balloon is inflated within the left atrium and then pulled back through the atrial septum. This tears the atrial septum, renders the flap valve of the foramen ovale incompetent, and so allows mixing of the systemic and pulmonary venous blood within the atrium.

• All patients with transposition of the great arteries will require surgery, which is usually the arterial switch procedure in the neonatal period. In this operation, performed in the first few days of life, the pulmonary artery and aorta are transected above the arterial valves and switched over. In addition, the coronary arteries have to be transferred across to the new aorta.

Transposition of the great arteries

Eisenmenger syndrome

If high pulmonary blood flow due to a large left-to-right shunt or common mixing is not treated at an early stage, then the pulmonary arteries become thick walled and the resistance to flow increases (Fig. 17.10). Gradually, those children that survive, become less symptomatic, as the shunt decreases. Eventually, at about 10–15 years, the shunt reverses and the teenager becomes blue, which is Eisenmenger syndrome. This situation is progressive and the adult will die in right heart failure at a variable age, usually in the fourth or fifth decade of life. Treatment is aimed at prevention of this condition, with early intervention for high pulmonary blood flow. Transplantation is not easily available although there are now medicines to palliate such pulmonary vascular disease (see Pulmonary hypertension, below).

Summary

Cyanotic congenital heart disease

Lesion	Clinical features	Management
Tetralogy of Fallot	Loud murmur at ULSE	Surgery at 6–9 months
	Clubbing of fingers and toes (older) Hypercyanotic spells
Transposition of the great arteries	Neonatal cyanosis	Prostaglandin infusion
	No murmur	Balloon atrial septostomy
		Arterial switch operation in neonatal period
Eisenmenger syndrome	No murmur	Medication to delay transplantation
	Right heart failure (late)

Common mixing (blue and breathless)

These include:

Atrioventricular septal defect (complete)

This occurs in:

• Atrioventricular septal defect (complete)

• Complex congenital heart disease

This is most commonly seen in children with Down syndrome (Fig. 17.11). A complete atrioventricular septal defect (cAVSD) is a defect in the middle of the heart with a single five-leaflet (common) valve between the atria and ventricles which stretches across the entire atrioventricular junction and tends to leak. As there is a large defect there is pulmonary hypertension.

Features of a complete atrioventricular septal defect are:

• Presentation on antenatal ultrasound screening

• Cyanosis at birth or heart failure at 2–3 weeks of life

• No murmur heard, the lesion being detected on routine echocardiography screening in a newborn baby with Down syndrome

• There is always a superior axis on the ECG

• Management is to treat heart failure medically (as for large VSD) and surgical repair at 3–6 months of age.

Complex congenital heart disease

It is difficult to generalise about these conditions, (tricuspid atresia, mitral atresia, double inlet left ventricle, common arterial trunk – truncus arteriosus) since their main presenting feature depends on whether cyanosis or heart failure is more predominant. Tricuspid atresia is the commonest.

Tricuspid atresia

In tricuspid atresia (Fig. 17.12), only the left ventricle is effective, the right being small and non-functional.

Clinical features

There is ‘common mixing’ of systemic and pulmonary venous return in the left atrium. Presentation is with cyanosis in the newborn period if duct dependent, or the child may be well at birth and become cyanosed or breathless.

Management

Early palliation (as with all the common mixing complex diseases) is performed to maintain a secure supply of blood to the lungs at low pressure, by:

• A Blalock–Taussig shunt insertion (between the subclavian and pulmonary artery) in children who are severely cyanosed

• Pulmonary artery banding operation to reduce pulmonary blood flow if breathless.

Completely corrective surgery is not possible with most, as there is often only one effective functioning ventricle. Palliation is performed (Glenn or hemi-Fontan operation connecting the superior vena cava to the pulmonary artery after 6 months of age and a Fontan operation to also connect the inferior vena cava to the pulmonary artery at 3–5 years).

Thus, the left ventricle drives blood around the body and systemic venous pressure supplies blood to the lungs. The Fontan operation results in a less than ideal functional outcome, but has the advantages of relieving cyanosis and removing the long-term volume load on the single functional ventricle.

Summary

Common mixing

Lesion	Clinical features	Management
Atrioventricular septal defect (complete)	Down syndrome (often) Cyanosis at birth Breathless at 2–3 weeks of life

Treat heart failure medically

Surgical repair at 3 months

Complex diseases (e.g. tricuspid atresia)

Cyanosis

Breathless

Shunt (Blalock–Taussig) or pulmonary artery banding,

then surgery (Fontan operation)

Outflow obstruction in the well child

These lesions are:

Aortic stenosis

The aortic valve leaflets are partly fused together, giving a restrictive exit from the left ventricle (Fig. 17.13a). There may be one to three aortic leaflets. Aortic stenosis may not be an isolated lesion. It is often associated with mitral valve stenosis and coarctation of the aorta, and their presence should always be excluded.

Clinical features

Most present with an asymptomatic murmur. Those with severe stenosis may present with reduced exercise tolerance, chest pain on exertion or syncope.

In the neonatal period, those with critical aortic stenosis and a duct-dependent systemic circulation may present with severe heart failure leading to shock.

Physical signs (Fig. 17.13b)

• Small volume, slow rising pulses

• Carotid thrill (always)

• Ejection systolic murmur maximal at the upper right sternal edge radiating to the neck

• Delayed and soft aortic second sound

• Apical ejection click.

Investigations

Chest radiograph (Fig. 17.13c)

Normal or prominent left ventricle with post-stenotic dilatation of the ascending aorta.

ECG (Fig. 17.13d)

There may be left ventricular hypertrophy.

Management

In children, regular clinical and echocardiographic assessment is required in order to assess when to intervene. Children with symptoms on exercise or who have a high resting pressure gradient (>64 mmHg) across the aortic valve will undergo balloon valvotomy. Balloon dilatation in older children is generally safe and uncomplicated, but in neonates this is much more difficult and dangerous.

Aortic stenosis

Most neonates and children with significant aortic valve stenosis requiring treatment in the first few years of life will eventually require aortic valve replacement. Early treatment is therefore palliative and directed towards delaying this for as long as possible.

Pulmonary stenosis

The pulmonary valve leaflets are partly fused together, giving a restrictive exit from the right ventricle.

Pulmonary stenosis

Clinical features

Most are asymptomatic (Fig. 17.14a). It is diagnosed clinically. A small number of neonates with critical pulmonary stenosis have a duct-dependent pulmonary circulation and present in the first few days of life with cyanosis.

Physical signs (Fig. 17.14b)

• An ejection systolic murmur best heard at the upper left sternal edge; thrill may be present

• An ejection click best heard at the upper left sternal edge

• When severe, there is a prominent right ventricular impulse (heave).

Investigations

Chest radiograph (Fig. 17.14c)

Normal or post-stenotic dilatation of the pulmonary artery.

ECG (Fig. 17.14d)

Shows evidence of right ventricular hypertrophy (upright T wave in V₁).

Management

Most children are asymptomatic and when the pressure gradient across the pulmonary valve becomes markedly increased (> about 64 mmHg), intervention will be required. Trans-catheter balloon dilatation is the treatment of choice in most children.

Adult-type coarctation of the aorta

This uncommon lesion (Fig. 17.15a) is not duct dependent. It gradually becomes more severe over many years.

Clinical features (Fig 17.15b)

• Asymptomatic

• Systemic hypertension in the right arm

• Ejection systolic murmur at upper sternal edge

• Collaterals heard with continuous murmur at the back

• Radio-femoral delay. This is due to blood bypassing the obstruction via collateral vessels in the chest wall and hence the pulse in the legs is delayed.

Investigations

Chest radiograph (Fig. 17.15c)

• ‘Rib notching’ due to the development of large collateral intercostal arteries running under the ribs posteriorly to bypass the obstruction

• ‘3’ sign, with visible notch in the descending aorta at site of the coarctation

Coarctation of the aorta

Summary

Outflow obstruction in the well child

Lesion	Signs	Management
Aortic stenosis	Murmur, upper right sternal edge; carotid thrill	Balloon dilatation
Pulmonary stenosis	Murmur, upper left sternal edge; no carotid thrill	Balloon dilatation
Coarctation (adult type)	Systemic hypertension	Stent insertion or surgery
	Radio-femoral delay

ECG

• Left ventricular hypertrophy (Fig. 17.15d).

Management

When the condition becomes severe, as assessed by echocardiography, a stent may be inserted at cardiac catheter. Sometimes surgical repair is required.

Outflow obstruction in the sick infant

These lesions include:

Clinical features are:

Interruption of the aortic arch

• Uncommon, with no connection between the proximal aorta and distal to the arterial duct, so that the cardiac output is dependent on right-to-left shunt via the duct Fig. 17.16

• A VSD is usually present

• Presentation is with shock in the neonatal period as above

• Complete correction with closure of the VSD and repair of the aortic arch is usually performed within the first few days of life.

• Association with other conditions (DiGeorge syndrome – absence of thymus, palatal defects, immunodeficiency and hypocalcaemia and 22q11.2 gene micro-deletion).

Hypoplastic left heart syndrome

In this condition there is underdevelopment of the entire left side of the heart (Fig. 17.17). The mitral valve is small or atretic, the left ventricle is diminutive and there is usually aortic valve atresia. The ascending aorta is very small, and there is almost invariably coarctation of the aorta.

Clinical features

These children may be detected antenatally at ultrasound screening. This allows for effective counselling and prevents the child from becoming sick after birth. If they do present after birth, they are the sickest of all neonates presenting with a duct-dependent systemic circulation. There is no flow through the left side of the heart, so ductal constriction leads to profound acidosis and rapid cardiovascular collapse. There is weakness or absence of all peripheral pulses, in contrast to weak femoral pulses in coarctation of the aorta.

Management

The management of this condition consists of a difficult neonatal operation called the Norwood procedure. This is followed by a further operation (Glenn or hemi-Fontan) at about 6 months and again (Fontan) at about 3 years.

Summary

Left heart outflow obstruction in the sick infant – duct-dependent lesions

Lesion	Clinical features	Management
Coarctation of the aorta	Circulatory collapse	Maintain ABC
	Absent femoral pulses	Prostaglandin infusion
Interruption of the aortic arch	Circulatory collapse	Maintain ABC
	Absent femoral pulses and absent left brachial pulse	Prostaglandin infusion
Hypoplastic left heart syndrome	Circulatory collapse	Maintain ABC
	All peripheral pulses absent	Prostaglandin infusion

Care following cardiac surgery

Most children recover rapidly following cardiac surgery and are back at nursery or school within a month. Exercise tolerance will be variable and most children can be allowed to find their own limits. Restricted exercise is advised only for children with severe residual aortic stenosis and for ventricular dysfunction.

Most of the children are followed up in specialist cardiac clinics. Most lead normal, unrestricted lives, but any change in symptoms, e.g. decreasing exercise tolerance or palpitations, requires further investigation. An increasing number of adolescents and young adults require revision of surgery performed in early life. The most common reason for this is replacement of artificial valves and relief of post-surgical suture line stenosis, for example re-coarctation or pulmonary artery stenosis.

Cardiac arrhythmias

Sinus arrhythmia is normal in children and is detectable as a cyclical change in heart rate with respiration. There is acceleration during inspiration and slowing on expiration (the heart rate changing by up to 30 beats/min).

Supraventricular tachycardia

This is the most common childhood arrhythmia. The heart rate is rapid, between 250 and 300 beats/min. It can cause poor cardiac output and pulmonary oedema. It typically presents with symptoms of heart failure in the neonate or young infant. It is a cause of hydrops fetalis and intrauterine death. The term re-entry tachycardia is used because a circuit of conduction is set up, with premature activation of the atrium via an accessory pathway. There is rarely a structural heart problem, but an echocardiogram should be performed.

Investigation

The ECG will generally show a narrow complex tachycardia of 250–300 beats/min (Fig. 17.18). It may be possible to discern a P wave after the QRS complex due to retrograde activation of the atrium via the accessory pathway. If heart failure is severe, there may be changes suggestive of myocardial ischaemia, with T-wave inversion in the lateral precordial leads. When in sinus rhythm, a short P–R interval may be discernible. In the Wolff–Parkinson–White (WPW) syndrome, the early antegrade activation of the ventricle via the pathway results in a short P–R interval and a delta wave.

Management

In the severely ill child, prompt restoration of sinus rhythm is the key to improvement. This is achieved by:

• Circulatory and respiratory support – tissue acidosis is corrected, positive pressure ventilation if required

• Vagal stimulating manoeuvres, e.g. carotid sinus massage or cold ice pack to face, successful in about 80%

• Intravenous adenosine – the treatment of choice. This is safe and effective, inducing atrioventricular block after rapid bolus injection. It terminates the tachycardia by breaking the re-entry circuit that is set up between the atrioventricular node and accessory pathway. It is given incrementally in increasing doses

• Electrical cardioversion with a synchronised DC shock (0.5–2 J/kg body weight) if adenosine fails.

Once sinus rhythm is restored, maintenance therapy will be required, e.g. with flecainide or sotalol. Digoxin can be used on its own when there is no overt pre-excitation wave (delta wave) on the resting ECG, but propranolol can be added in the presence of pre-excitation. Even though the resting ECG may remain abnormal, 90% of children will have no further attacks after infancy. Treatment is therefore stopped at 1 year of age. Those who have WPW syndrome need to be assessed to ensure they cannot conduct quickly and this may be undertaken in teenage life, with atrial pacing. This will reduce the small chance of sudden death in such patients. Those who relapse or are at risk are usually treated with percutaneous radiofrequency ablation or cryoablation of the accessory pathway.

Congenital complete heart block

This is a rare condition (Fig. 17.19) which is usually related to the presence of anti-Ro or anti-La antibodies in maternal serum. These mothers will have either manifest or latent connective tissue disorders. Subsequent pregnancies are often affected. This antibody appears to prevent normal development of the electrical conduction system in the developing heart, with atrophy and fibrosis of the atrioventricular node. It may cause fetal hydrops, death in utero and heart failure in the neonatal period. However, most remain symptom-free for many years, but a few become symptomatic with presyncope or syncope. All children with symptoms require insertion of an endocardial pacemaker. There are other rare causes of complete heart block.

Syncope

This is a common symptom in teenagers and usually does not represent cardiac disease.

The causes are:

In most, the cause is non-cardiac. Features suggestive of a cardiac cause are:

Check blood pressure and signs of cardiac disease (murmur, femoral pulses, Marfan syndrome).

Investigate with an ECG.

Chest pains

Rarely due to cardiac disease in children. Only those occurring with palpitations or on exertion suggest a possible cardiac origin.

Rheumatic fever

This is now rare in the developed world, but remains the most important cause of heart disease in children worldwide. Improvements in sanitation, social factors, the more liberal use of antibiotics and changes in streptococcal virulence have led to its virtual disappearance in developed countries. In susceptible individuals, there is an abnormal immune response to a preceding infection with group A β-haemolytic streptococcus. The disease mainly affects children aged 5–15 years.

Clinical features

After a latent interval of 2–6 weeks following a pharyngeal infection, polyarthritis, mild fever and malaise develop. The clinical features and diagnostic criteria are shown in Figure 17.20.

Chronic rheumatic heart disease

The most common form of long-term damage from scarring and fibrosis of the valve tissue of the heart is mitral stenosis. If there have been repeated attacks of rheumatic fever with carditis, this may occur as early as the second decade of life, but usually symptoms do not develop until early adult life. Although the mitral valve is the most frequently affected, aortic, tricuspid and, rarely, pulmonary valve disease may occur.

Management

The acute episode is usually treated with bed rest and anti-inflammatory agents. While there is evidence of active myocarditis (echocardiographic changes with a raised ESR), bed rest and limitation of exercise are essential. Aspirin is very effective at suppressing the inflammatory response of the joints and heart. It needs to be given in high dosage and serum levels monitored. If the fever and inflammation do not resolve rapidly, corticosteroids will be required. Symptomatic heart failure is treated with diuretics and ACE inhibitors, and significant pericardial effusions will require pericardiocentesis. Anti-streptococcal antibiotics may be given if there is any evidence of persisting infection.

Following resolution of the acute episode, recurrence should be prevented. Monthly injections of benzathine penicillin is the most effective prophylaxis. Alternatively, the penicillin can be given orally every day, but compliance may be a problem. Oral erythromycin can be substituted in those sensitive to penicillin. The length of treatment is controversial. Most recommend treatment to the age of 18 or 21 years, but, more recently, lifelong prophylaxis has been advocated. The severity of eventual rheumatic valvular disease relates to the number of childhood episodes of rheumatic fever.

Infective endocarditis

All children of any age with congenital heart disease (except secundum ASD), including neonates, are at risk of infective endocarditis. The risk is highest when there is a turbulent jet of blood, as with a VSD, coarctation of the aorta and persistent ductus arteriosus or if prosthetic material has been inserted at surgery. It may be difficult to diagnose, but should be suspected in any child or adult with a sustained fever, malaise, raised ESR, unexplained anaemia or haematuria. The presence of the classical peripheral stigmata of infective endocarditis should not be relied upon.

Clinical signs

• Fever

• Anaemia and pallor

• Splinter haemorrhages in nailbed

• Clubbing (late)

• Necrotic skin lesions (Fig. 17.21)

• Changing cardiac signs

• Splenomegaly

• Neurological signs from cerebral infarction

• Retinal infarcts

• Arthritis/arthralgia

• Haematuria (microscopic).

Diagnosis

Multiple blood cultures should be taken before antibiotics are started. Detailed cross-sectional echocardiography may confirm the diagnosis by identification of vegetations but can never exclude it. The vegetations consist of fibrin and platelets and contain infecting organisms. Acute-phase reactants are raised and can be useful to monitor response to treatment.

The most common causative organism is α-haemolytic streptococcus (Streptococcus viridans). Bacterial endocarditis is usually treated with high-dose penicillin in combination with an aminoglycoside, giving 6 weeks of intravenous therapy and checking that the serum level of the antibiotic will kill the organism. If there is infected prosthetic material, e.g. prosthetic valves, VSD patches or shunts, there is less chance of complete eradication and surgical removal may be required.

Prophylaxis

The most important factor in prophylaxis against endocarditis is good dental hygiene, and this should be strongly encouraged in all children with congenital heart disease.

Antibiotic prophylaxis is no longer recommended in the UK, but may be required in other countries for:

• Dental treatment, however trivial

• Surgery, which is likely to be associated with bacteraemia.

Myocarditis/cardiomyopathy

Dilated cardiomyopathy (a large, poorly contracting heart) may be inherited, secondary to metabolic disease or may result from a direct viral infection of the myocardium. It should be suspected in any child with an enlarged heart and heart failure who has previously been well. The diagnosis is readily made on echocardiography. Treatment is symptomatic with diuretics and ACE inhibitors and carvedilol, a β-adrenoceptor blocking agent. The role of steroids and immunoglobulin infusion is controversial. Myocarditis usually improves spontaneously, but some children ultimately require heart transplantation. Other cardiomyopathies (hypertrophic/restrictive) are rare in childhood and are usually related to a systemic disease (e.g. Hurler, Pompe or Noonan syndromes).

Kawasaki disease

This mainly affects children of 6 months to 5 years. Clinical features are described in Chapter 14. It is uncommon but can cause significant cardiac disease. An echocardiogram is performed at diagnosis which may show a pericardial effusion, myocardial disease (poor contractility), endocardial disease (valve regurgitation) or coronary disease with aneurysm formation, which can be giant (>8 mm in diameter). If the coronary arteries are abnormal, angiography (Fig. 17.22) or MRI will be required.

Pulmonary hypertension

This is of increasing importance in paediatric cardiology, as there is now effective medication for most causes. It can be caused by a number of different diseases (Box 17.4). From the cardiac perspective, most children with pulmonary hypertension (high pulmonary artery pressure, mean >25 mmHg), have a large post-tricuspid shunt with high pulmonary blood flow and low resistance, e.g. VSD, AVSD or PDA. The pressure falls to normal if the defect is corrected by surgery within 6 months of age. If these children are left untreated, however, the high flow and pressure causes irreversible damage to the pulmonary vascular bed (pulmonary vascular disease), which is not correctable other than by heart/lung transplantation.

Many medical therapies are now available, which may act on the pulmonary vasculature on the cyclic GMP (guanosine monophosphate) pathway (e.g. inhaled nitric oxide, intravenous magnesium sulphate and oral phosphodiesterase inhibitors including sildenafil) or on the cyclic AMP pathway (intravenous prostacyclin or inhaled iloprost). In addition, endothelin receptor antagonists are valuable but expensive therapy, e.g. oral Bosentan. Anticoagulation is often given with heparin, aspirin or warfarin. These medications allow transplantation to be delayed for many years.