After reading this chapter you should:
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understand investigation of cardiac diseases, e.g. ECG, echocardiograms, cardiac catheterisation and their appropriate selection in diagnosis and management
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know the various presentations of congenital heart problems and to be able to assess, diagnose and manage
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be able to assess, diagnose and manage murmurs, chest pain, palpitations, cardiac arrhythmias and syncope
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be able to assess, diagnose and manage heart failure, myocarditis, pericardial disease and cardiomyopathy
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be able to assess, diagnose and manage pulmonary hypertension and make appropriate referrals
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be able to assess, diagnose and manage infective endocarditis
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know the cardiac complications of other system disorders
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know the indications and common side effects of drugs used to treat common cardiac conditions including duct dependent cyanosis, heart failure and arrhythmias
Many conditions will impact on cardiac function in children and although specific diseases of the heart are less common, they are a regular feature in the clinical practice of paediatricians.
Investigations
Chest radiograph
A plain radiograph can provide information on cardiac shape and size, appearances of main vessels and any change in pulmonary perfusion. Many of the classical appearances of congenital heart disease are now rarely seen on radiographs as echocardiography has superseded the plain film as the most appropriate initial investigation. Furthermore, treatments will often be undertaken before classical radiological features develop. It is, however, important to understand the contributions that the various cardiac structures make to the radiological appearance ( Figure 16.1 ).
Electrocardiogram
A 12 lead ECG is a basic investigation and will reveal rate, rhythm, wave interval and axis ( table 16.1 ). It has the added issue in paediatric practice in that it changes in appearance depending on the age of the child ( Figure 16.2 ). The ECG of a newborn baby will reflect right ventricular dominance up to the age of 6 months.
| Wave | Appearance | Implication |
|---|---|---|
| P wave (right axis deviation) | prominent (peaked) | right atrial hypertrophy (p pulmonale) |
| P wave | prolonged m shaped | left atrial hypertrophy (p mitrale) |
| ST segment (low voltages) | raised | pericarditis or pericardial effusion |
| QT interval | prolonged | hypocalcaemia |
| QT interval | shortened | hypercalcaemia |
| QRS complex | widened | hyperkalaemia |
| T wave (with U wave) | flattened | hypokalaemia |
| T wave | peaked | hyperkalaemia |
| T wave | upright in V1 | right ventricular hypertrophy |
| T wave | downward in V6 | left ventricle cardiomyopathy |
Ambulatory ECG monitoring
Useful for patients who may have episodic arrhythmias who have a 3 lead ECG attached to a recording device for one or more days. Abnormal rhythms, however, can still be difficult to record even with this close monitoring. Alternatives are now available such as rhythm cards, digital watches or smartphone ECG recordings.
Echocardiography
Echocardiography is a skilled technique which gives real-time information about cardiac structure and blood flow. The AKP exam will not expect candidates to be able to interpret echocardiographic images.
Cardiac catheterisation
Catheterisation will allow the insertion of specific devices which may close defects or dilate strictures. The inserted catheter can also establish pressures and oxygen saturations in each of the four chambers and the major vessels ( Figure 16.3 ). Such information will improve the understanding of the problem and the extend of any abnormalities.
Hyperoxia test
The hyperoxia test is used in newborn babies where there is a concern whether cyanosis is cardiac or noncardiac in origin. The baby is exposed to 100% oxygen for 10 minutes (via intubation or in head box) after which an arterial blood gas is taken. If the PaO 2 is more than 20 kPa then the cyanosis is not due to congenital heart disease.
Congenital heart disease
Congenital heart disease is identified through antenatal echocardiogram, by the detection of a heart murmur on routine checks and by the acute presentation of a child with cyanosis, heart failure or collapse ( table 16.2 ). Cyanosis is the result of right to left shunting of blood either through defects or connections or through common mixing in the circulation.
Clinical features
Ultrasonography of the fetal heart has become a routine part of the fetal anomaly scan performed in between 18 and 20 weeks’ gestation, and approximately 70% of those infants who require surgery in the first 6 months of life are diagnosed in this way. Early diagnosis allows the parents to be counselled appropriately and, depending on the diagnosis, the choice of terminating the pregnancy. The majority, however, continue with the pregnancy and can have their child’s management planned antenatally. Those babies with a duct-dependent lesion, which will need treatment within the first few days of life, can be offered delivery at, or close to, a cardiac centre. They will be commenced on prostaglandin at birth in order to prevent them from becoming sick and collapsing.
The most common presentation of more minor congenital heart disease is with a heart murmur although the vast majority of such children will have a normal heart. The murmur is then described as ‘innocent’ or ‘benign’.
Babies with a pathological left to right shunt will present after the first few days of life, initially with a heart murmur, or at a later date, with signs of heart failure. They never have a murmur on the first day of life, due to the fact that the pulmonary vascular pressures are high, so that there is no ‘shunting’ until these pressures start to fall. These signs are often detected at the 6 week GP baby check when the baby has faltering growth or may be breathlessness, especially on feeding. Conditions such as ASD, VSD and PDA will present in this way.
Those with a right to left shunt can present at any age, but the most critical are those with a duct-dependent cyanotic cardiac lesion where the pulmonary circulation is dependent on a patent ductus arteriosus. They are diagnosed soon after birth when oxygen saturations are found to be less than 94%. Many children with Tetralogy of Fallot are not cyanosed at birth and instead present with a murmur on the first day of life (due to the narrow right ventricular outflow tract).
Children with lesions which result in a common mixing of blood within the circulation will present with breathlessness (due to left to right shunt) and cyanosis (due to right to left shunt) and usually have very complex heart disease.
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Tetralogy of Fallot
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Transposition of the Great Vessels
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Truncus Arteriosus
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Total Anomalous Pulmonary Venous Drainage
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Tricuspid Atresia
Children with a mild obstructive cardiac lesion usually present with a heart murmur and are often well and without symptoms. Some babies with severe obstructive cardiac lesions, however, may have a duct-dependent systemic circulation and they will then present in the first few days of life as the duct closes.
| Physiology | Symptoms | Conditions |
|---|---|---|
| left to right shunts | breathless or asymptomatic | atrial septal defect ventricular septal defect persistent ductus arteriosus |
| right to left shunts | cyanosis | tetralogy of Fallot transposition of the great arteries Eisenmenger syndrome |
| common mixing | breathless; cyanosis | complete atrio-ventricular septal defect complex heart disease |
| well child with obstruction | asymptomatic | aortic stenosis pulmonary stenosis |
| sick neonate | collapse | coarctation of the aorta hypoplastic left heart syndrome totally anomalous pulmonary venous connection |
Left to right shunt ( table 16.3 )
| Defect | Sign | Investigation | Management |
|---|---|---|---|
| Atrial septal defect—secundum | ejection systolic murmur at upper left sternal edge | ECG: partial right bundle branch block CXR: cardiomegaly | ASD closure device inserted in catheter lab age 3 years |
| Atrial septal defect—primum—now called partial AVSD | ejection systolic murmur at upper left sternal edge apical pansystolic murmur | ECG: superior axis CXR: cardiomegaly | open heart surgery at 3 years to close the defect and repair the leaky left AV valve |
| Ventricular septal defect | pan-systolic murmur at left lower sternal edge | small defect—closes spontaneously large defect—undergo open heart surgery at 3–6 months | |
| Persistent ductus arteriosus | continuous (machinery) murmur at upper left sternal edge | PDA closure device in catheter lab age 1 year |
Atrial septal defect (secundum)
The majority of children with an isolated secundum ASD will present in infancy with a murmur found on routine examination or when examined because of unconnected chest infection. Classically, it is an ejection systolic murmur at the upper left sternal edge due to the increased flow across the pulmonary valve. It is rare to hear the additional fixed-split of the second heart sound in children.
Investigations
The ECG will show sinus rhythm with evidence of incomplete right bundle branch block and possibly right ventricular hypertrophy. A chest radiograph may show right atrial enlargement, a large heart and pulmonary plethora. The diagnosis is confirmed by echocardiography. This allows measurement of the size and location of the defect and assessment of the degree of right ventricular enlargement.
Treatment and management
For significant ASDs, closure is commonly performed around the age of 3 years using an ASD closure device at cardiac catheterisation which has a very low mortality and an excellent long-term prognosis.
Partial atrio-ventricular septal defect
Previously called atrial septal defect (primum). The child may present in heart failure in infancy if there is significant left to right shunting with left atrio-ventricular valve regurgitation. The ECG shows superior axis whilst the radiograph shows cardiomegaly. Correction requires patch closure of the defect and, in all patients, repair of the left AV valve (which leaks because it is not a mitral valve).
Ventricular septal defect
This is the most common congenital heart disease, and those with significant defects, if not detected antenatally, will usually present in the first few weeks of life. The child will have no signs or symptoms on the first day but will gradually develop a murmur and heart failure (if a large defect) over the first week as the pulmonary vascular resistance falls. The classical murmur is a loud pansystolic murmur at the lower left sternal edge. If there is heart failure, this is manifested as breathlessness, faltering growth, poor feeding and cold hands and feet. The defect is often associated with genetic syndromes.
The chest radiograph will show cardiomegaly and pulmonary plethora, the ECG will show bi-ventricular hypertrophy (large total voltage in V3 and V4) and the echocardiogram will establish the definitive diagnosis.
Large defects are closed at 3–4 months of age but, prior to that, the child will need treatment with diuretics and ACE inhibitors. Added calories are introduced to allow the child to put on some weight as cardiopulmonary bypass is undertaken when the child is around 4 kg in weight to achieve the best outcome with the lowest risks.
Those with small muscular VSDs are usually asymptomatic and most do not require any active treatment. The defects tend to become smaller with time and the majority undergo spontaneous closure. Those with a small (restrictive) perimembranous VSD need ongoing monitoring as the aortic valve may become distorted over time.
Persistent ductus arteriosus
These are defined as still being present one month after the baby should have been born and therefore excludes preterm babies who are still within their ‘due’ dates. They may have no symptoms or may have significant heart failure, and the severity is related to the magnitude of left to right shunting from aorta to pulmonary artery. Their cardinal signs are a systolic or continuous murmur at the upper left sternal edge and the baby may have a collapsing pulse as the blood runs back down the duct in diastole.
The term ‘patent ductus arteriosus’ refers to preterm babies who are still within their ‘due date’ and where the duct has not closed. The condition is important in the ventilator dependent preterm infant with lung disease.
Investigations
An infant with a large PDA may have cardiomegaly and pulmonary plethora on a chest radiograph and the ECG will show bi-ventricular hypertrophy (large total voltage in V3 and V4). Small defects will show no abnormalities on these investigations. Echocardiography is used to make the definitive diagnosis.
Treatment and management
Large defects may need closure at a young age by catheter device or by lateral thoracotomy surgical operation. The preferred option is to wait until they are over 5 kg and then close them with a device in the catheter laboratory. Until that time, diuretics and added calories can allow the child to put on some weight to reduce the risk of operation.
Right to left shunt ( table 16.4 )
These present with varying degrees of cyanosis if not detected antenatally.
| Defect | Sign (all are cyanosed) | Management |
|---|---|---|
| Tetralogy of Fallot | long harsh systolic murmur at mid left sternal edge | open heart surgery at 6 months |
| Transposition of the Great Arteries | cyanosis only in most patients may collapse at 2 days old when PDA closes | open heart surgery at 5–7 days (arterial switch operation) |
| Eisenmenger syndrome | cyanosis only, no murmur tend to be teenagers or older | result of untreated large septal defect pulmonary vasodilator medication |
Tetralogy of Fallot
This condition is most easily understood with four defects (VSD, sub pulmonary stenosis, overriding aorta and, as a result, right ventricular hypertrophy). The sub pulmonary stenosis forces deoxygenated blood from the right ventricle to the left via the septal defect and patients are cyanosed with oxygen saturations below 94%. The condition is usually identified on an antenatal booking scan. The infant will have no symptoms on the first day of life but will have a loud murmur (unlike in VSD) and is unlikely to be cyanosed initially. The obvious cyanosis will gradually develop and increase over the first few months of life and examination reveals a long, harsh murmur at the mid left sternal edge. Many are associated with 22q11 microdeletion. The baby will usually grow well; some infants will develop episodes when they become very blue and then pale before becoming unconscious and limp. This is called a ‘spell’ and is potentially dangerous as it represents significant reduction in pulmonary blood flow that can be confirmed acutely by absence of their heart murmur (since no blood is crossing the pulmonary valve).
Investigations
The ECG will show sinus rhythm with evidence of right ventricular hypertrophy (upright T wave in lead V1). The chest radiograph can show pulmonary oligaemia and a boot-shaped cardiac outline—which is the result of right ventricular hypertrophy and hypoplasia of the pulmonary arch ( Figure 16.4 ). The diagnosis is confirmed by echocardiography and allows definition of the precise anatomy.
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