Congenital Heart Disease

This article aims to provide a brief overview of congenital heart disease, including subtypes, clinical signs, investigations and management.

Acyanotic lesions

Acyanotic cardiac lesions include:

• Ventricular septal defects (VSD)
• Atrial septal defects (ASD)
• Patent ductus arteriosis (PDA)

Acyantoic cardiac lesions have the following features:

• Left to right shunting, mixing of oxygenated blood with deoxygenated blood
• Increased pulmonary blood flow → risk of pulmonary hypertension and untreated acyanotic heart disease can lead to Eisenmenger syndrome
• Lesions that are above the level of the nipple usually give rise to ejection systolic murmurs while lesions below the level of the nipple typically cause pan systolic murmurs

Ventricular septal defect (VSD)

Symptoms

Symptoms differ depending on the size of the defect:

• Small – may be asymptomatic, normal growth
• Moderate – poor feeding, failure to thrive (FTT), short of breath (SOB)
• Large – poor feeding, FTT (falls below centiles), SOB, sweaty and pale with feeds

Epidemiology

• Most common congenital heart lesion (15-20%)
• Associated with Down’s syndrome (AVSD)

 Time of presentation

• Antenatal diagnosis at 16-18 weeks
• Presentation at 6-8 weeks
• Congestive heart failure typically presents after 4-6 weeks
• Persistent pulmonary hypertension of the newborn (PPHN) may become established by 6-12 months

Clinical findings

Palpate:

• Check for the presence of a thrill
• Might be useful to palpate the liver (enlarged in heart failure)

Auscultate:

• Pan-systolic murmur heard loudest at the lower left sternal border (LLSB)
• Typically grade 3-4
• Loud P2 suggests the presence of pulmonary hypertension

Investigations

• Pulse oximetry – to determine the level of oxygen saturation
• Echocardiography – visualise defect directly
• CXR – cardiomegaly and pulmonary oedema (increased pulmonary vascular markings) if severe VSD (presence of heart failure), enlarged pulmonary artery
• ECG:
  • In patients with moderate or large VSD, the ECG may demonstrate LV hypertrophy (LVH) manifesting as increased voltage in V5 and V6 or leads II, III, and aVF
  • In patients with elevated RV pressure, the ECG demonstrates RV hypertrophy (RVH), often manifesting as tall R waves in leads V4R and V1, or upright T waves in these leads beyond the first 24 hours of life, in addition to LVH

Management

• Small lesion: < 5mm usually close spontaneously, no repair required (30-40%)
• Moderate lesion:
  • Diuretic therapy (furosemide and spironolactone)
  • Feeding with high caloric feeds (Infantrini)
• Large lesion:
  • Manage as per moderate lesion
  • Optimise weight gain for surgery
  • Schedule for surgery before 12 months to prevent persistent pulmonary hypertension of the newborn (PPHN)

Atrial septal defect

Symptoms

• Typically asymptomatic
• Some children will have recurrent chest infections

Epidemiology

• Second most common acyanotic heart lesion (5-10%)

Time of presentation

• The mean age of diagnosis is 4.5 years from an incidental finding of murmur
• Symptomatic presentation is usually before the age of 40 years with arrhythmias, dyspnoea

Clinical features

• May also have no auscultatory finding in infants (asymptomatic)

Auscultate:

• Ejection systolic murmur heard loudest at the upper-left sternal border (ULSB)
• Widely fixed splitting of the second heart sound (L→ R shunting increases RV filling, thus RV ejection time is increased and pulmonary valve closure is delayed for a significant amount of time after aortic valve closure)

Investigations

• Pulse oximetry
• ECHO – visualise defect directly, shows dilated RV and increased RV filling and ejection time
• CXR – usually no findings
• ECG – incomplete RBBB

Management

• Most children are asymptomatic and rarely require congestive heart failure (CHF) therapy
• Spontaneous closure in lesions smaller than 7-8mm
• Large defects require repair – percutaneous (catheter closure) or surgery using median sternotomy incision

Patent ductus arteriosus

Symptoms

Dependent on the size of the lesion:

• Small – asymptomatic
• Moderate – congestive heart failure with failure to thrive (poor feeding)
• Large – poor feeding, severe failure to thrive, recurrent lower respiratory tract infections (preterm infants may experience failure to wean from ventilation)

Epidemiology

• 5-10% of all congenital heart defects
• Very common in preterm infants

Time of presentation

• Symptoms usually present 3-5 days after birth when the duct begins to close

Clinical features

Palpate:

• Might be useful to palpate the liver (enlarged in heart failure)
• Bounding pulses and wide pulse pressure

Auscultate:

• Continuous machinery murmur typically heard at the upper-left sternal border (best heard below left the clavicle)
• Check for the presence of a thrill at the upper left sternal border

Investigations

• 2D echocardiography and Doppler
• CXR and ECG are less useful in diagnosing PDA

Management

• If preterm – good probability of spontaneous closure
• If term – less likely to close spontaneously
• Medical – indomethacin/ibuprofen (not effective in term infants)
• Surgical – catheter closure or PDA ligation (left lateral thoracotomy incision) when weight is at least 5kg

Outflow tract obstruction: Coarctation of the aorta

Pathophysiology

• Obstruction to the left ventricles outflow tract leads to an increase in left ventricular afterload which causes left ventricular hypertrophy
• Neonates with severe aortic coarctation can develop heart failure

Epidemiology

• Approximately 5% of all congenital heart defects
• Associated with Turner’s syndrome (5-15% of girls with coarctation)

Time of presentation

• Symptoms present 3-5 days after birth when the duct begins to close as the PDA and foramen ovale allows blood to bypass the outflow obstruction

Clinical features

Palpate:

• Systolic blood pressure is high when measured with BP cuff
• Absent femoral pulses (do 4-limb BP measurement)
• Cold extremities (especially feet)
• Hepatomegaly in heart failure due to severe coarctation

Auscultate:

• Murmur heard at the back between the scapulae

Investigations

• 2D echocardiogram and Doppler – direct visualisation of defect
• CXR and ECG are less useful in the diagnosis

Management

Medical therapy:

• Continuous intravenous infusion of prostaglandin E1 to keep the ductus arteriosus open
• Dopamine or Dobutamine to improve contractility in those with heart failure
• Supportive care to correct metabolic acidosis, hypoglycemia, respiratory failure, and anaemia that may contribute to or be a consequence of heart failure

Surgical repair:

• Balloon angioplasty
• Resection with end-to-end angioplasty
• Bypass graft
• Subclavian flap

Cyanotic lesions (6 Ts)

Occur due to the mixing of deoxygenated blood with oxygenated blood (right → left shunt).

Differential diagnoses of cyanotic lesions using the 6 ‘T’s are:

• Tetralogy of Fallot
• Transposition of great arteries
• Truncus arteriosus
• Total anomalous pulmonary venous connection
• Tricuspid valve abnormalities
• Ton of others – hypoplastic left heart, double outlet right ventricle, pulmonary atresia

Tetralogy of Fallot

Tetralogy of Fallot features the following four abnormalities:

1. Ventricular septal defect
2. Overriding aorta
3. Pulmonary stenosis
4. Right ventricular hypertrophy

Symptoms