Key Facts

Congenital heart disease is the most common category of congenital malformation, encompassing a wide spectrum from minor defects requiring no intervention to complex lesions requiring neonatal surgery. Early detection through the NIPE programme and pulse oximetry screening has improved outcomes.

Epidemiology

Incidence is approximately 6-8 per 1,000 live births. Approximately 25% of CHD is critical, requiring intervention in the first year of life. Survival has improved dramatically — over 90% of children with CHD now survive to adulthood. CHD accounts for approximately 3-4% of infant deaths in the UK.

Aetiology

Most CHD is multifactorial (genetic + environmental). Identifiable causes include:

• Chromosomal: Trisomy 21 (AVSD), Turner syndrome (coarctation), trisomy 13/18 (multiple defects)
• Microdeletion: 22q11.2/DiGeorge (interrupted aortic arch, truncus arteriosus, TOF)
• Single gene: Noonan syndrome (pulmonary stenosis), Marfan syndrome (aortic root dilatation)
• Maternal: Diabetes (TGA, VSD), rubella (PDA, pulmonary stenosis), alcohol (VSD, ASD), SLE (heart block), phenytoin, lithium (Ebstein's anomaly)

Pathophysiology

Acyanotic (left-to-right shunts): Blood shunts from systemic to pulmonary circulation → pulmonary overcirculation → heart failure. If uncorrected, pulmonary vascular resistance rises irreversibly → Eisenmenger syndrome (shunt reversal, cyanosis).

Cyanotic (right-to-left shunts): Deoxygenated blood enters systemic circulation → cyanosis. Two physiological groups:

• Reduced pulmonary blood flow: TOF, pulmonary atresia, tricuspid atresia
• Abnormal mixing/parallel circulations: TGA, TAPVR, truncus arteriosus

Acyanotic Lesions

• Heart failure: Tachypnoea, poor feeding, faltering growth, sweating during feeds, hepatomegaly
• Murmur detected on NIPE or routine examination
• Recurrent lower respiratory tract infections

Cyanotic Lesions

• Central cyanosis not improving with supplemental oxygen (failed hyperoxia test: PaO2 remains <15kPa on 100% O2)
• Tet spells in TOF: Paroxysmal cyanosis, irritability, hyperpnoea — infant draws knees to chest
• Duct-dependent lesions presenting with collapse at day 2-7 when ductus closes

Specific Lesions

• VSD: Pansystolic murmur at left sternal edge; small VSDs louder than large
• ASD: Fixed split S2, ejection systolic murmur at upper left sternal edge
• PDA: Continuous machinery murmur below left clavicle; bounding pulses
• TOF: Ejection systolic murmur (pulmonary stenosis), cyanosis; boot-shaped heart on CXR
• TGA: Cyanosis from birth, single loud S2; egg-on-side cardiac silhouette
• Coarctation: Radio-femoral delay, upper limb hypertension, ejection systolic murmur

Red Flags

• Cyanosis unresponsive to oxygen in a neonate — duct-dependent CHD until proven otherwise
• Collapse at day 2-7 of life — consider duct-dependent lesion
• Absent femoral pulses — coarctation of the aorta
• Hepatomegaly with tachypnoea in infant — heart failure

Bedside

• Pulse oximetry screening: Pre-ductal (right hand) and post-ductal (either foot) saturations; >3% difference suggests duct-dependent lesion or coarctation
• Hyperoxia test: PaO2 after 15 min of 100% O2 — if <15kPa, cyanotic CHD likely
• 4-limb blood pressure: Coarctation causes >20mmHg difference between upper and lower limbs
• ECG: Axis deviation, chamber hypertrophy, rhythm abnormalities

Bloods

• Blood gas: Assess oxygenation, metabolic acidosis (poor cardiac output)
• FBC: Polycythaemia in chronic cyanosis
• Chromosomal analysis/microarray: If dysmorphic features — check for trisomy 21, 22q11.2 deletion

Imaging

• Chest X-ray: Heart size and shape, pulmonary vascularity (plethoric vs oligaemic)
• Echocardiography: Gold standard — defines anatomy, shunt direction, pressure gradients
• Cardiac MRI: For complex anatomy, great vessel assessment, quantification of shunts
• Cardiac catheterisation: Pre-surgical planning, interventional procedures

Special Tests

• CT angiography: Vascular rings, aortic arch anatomy
• Genetic testing: Karyotype, FISH for 22q11.2, microarray

Non-pharmacological

• Feeding support: NG feeds, high-calorie formula for failure to thrive
• Infection prevention: RSV prophylaxis with palivizumab for haemodynamically significant CHD (NICE TA791)
• Endocarditis prophylaxis: Good dental hygiene; antibiotic prophylaxis no longer routinely recommended (NICE CG64) except for high-risk procedures

Pharmacological

• Duct-dependent lesions: Alprostadil (PGE1) 5-20 ng/kg/min IV — maintain ductal patency (side effects: apnoea, fever, hypotension)
• Heart failure: Furosemide 0.5-2mg/kg/dose BD-TDS, captopril 0.1-0.3mg/kg TDS, spironolactone 1-2mg/kg BD
• Tet spells: Knee-to-chest position, oxygen, morphine 0.1mg/kg IV, IV fluids, phenylephrine 5-20mcg/kg IV; propranolol 0.5-1mg/kg QDS for prevention

Surgical/Interventional

• VSD: Surgical patch closure if large/symptomatic; catheter device closure selected cases
• ASD: Catheter device closure (secundum); surgical for primum/sinus venosus
• PDA: Catheter occlusion or surgical ligation; ibuprofen/paracetamol for premature infants
• TOF: Complete repair at 3-6 months (VSD closure + RVOT relief)
• TGA: Arterial switch operation (Jatene) in first 2 weeks; balloon atrial septostomy (Rashkind) as bridge
• Coarctation: Surgical repair or balloon angioplasty ± stenting

Referral Criteria

• Any suspected CHD — urgent paediatric cardiology referral
• Cyanosis unresponsive to O2 — emergency transfer to cardiac centre
• Pathological murmur with symptoms — echocardiography within 2 weeks

• Overall CHD survival: >90% now survive to adulthood in the UK
• VSD: ~80% of small muscular VSDs close spontaneously; large VSDs require surgery with excellent outcomes
• ASD: Life expectancy normal after closure; risk of atrial arrhythmias if repaired late
• TOF: >95% operative survival; most require pulmonary valve replacement in adulthood
• TGA post-arterial switch: >97% operative survival; excellent long-term outcomes
• Eisenmenger syndrome: Once established, 5-year survival approximately 80%; heart-lung transplant only curative option
• Adults with CHD: Growing population — estimated 220,000 adults living with CHD in the UK

Common CHD Lesions and Associations

CXR Appearances