Congenital heart disease

Clinical presentation

• Growth failure, sweating, dyspnoea
• Tachypnoea, cardiomegaly, hepatomegaly, gallop rhythm, tachycardia, cool/mottled extremities
• Clinical and X-ray signs of lung congestion
• Liver enlarges rapidly in infants (much more helpful than JVP)

Differential diagnosis

Heart failure at birth

• Birth asphyxia
• Sepsis
• Severe anaemia
• Obstructive left-sided lesions presenting after closure of ductus
  • Coarctation of aorta
  • Aortic stenosis
  • Interrupted aortic arch
  • Hypoplastic left heart syndrome
• Truncus arteriosus
• Systemic AV fistula (liver/kidney)
• Congenital cardiomyopathy
• Arrhythmia: Congenital SVT or heart block
• Persistant pulmonary HTN of newborn

Heart failure in first 8 weeks

• Large left-to-right shunts
  • VSD, PDA, total anomalous pulmonary venous drainage
• Infiltrative cardiomyopathy
• Anomalous origin of left coronary artery from pulmonary artery
• Hypothyroidism

Heart failure later in childhood

• Congenital heart disease: Subaortic stenosis, VSD
• Post-operative: Fontan procedure, obstructed prosthetic valve, post-ventriculotomy, coronary artery injury, large Blalock-Taussig shunt
• Cardiomyopathy: Infective, infiltrative, asphyxia, ischaemia (Kawasaki), toxic (eucalyptus oil, carbamazepine, verapamil, flecainide), heart transplant rejection
• Valvular: Rheumatic, IE, trauma
• Arrhythmia: SVT, complete heart block
• Severe polycythaemia or anaemia
• Cor pulmonale
• Acute HTN: GN, HUS

Differential diagnosis by cyanosis

• Acyanotic (pink or grey)
  • Left-to-right shunt
    • VSD
    • ASD
    • AVSD
    • PDA
  • No shunt
    • Aortic stenosis
    • Pulmonary stenosis
    • Tricuspid stenosis
    • Coarctation
• Cyanotic
  • Tetralogy of Fallot
  • Transposition of great vessels
  • Hypoplastic left heart
  • Pulmonary atresia
  • Eisenmenger’s (later life L -> R becomes R -> L with pulmonary HTN)
  • Truncus arteriosus
  • Tricuspid atresia
  • Total anomalous pulmonary venous drainage (TAPVD)
  • Ebstein anomaly (inferior displacement of TV into RV with R -> L shunt through ASD = Lithium)

Age <1 month or >1 month

• If <1 month with cyanosis or shock
  • Consider duct-dependent congenital heart disease until proven otherwise
  • Almost always left heart/ductal dependent lesion e.g. TofF
  • Almost always benefits from prostaglandin
• If >1 month
  • Left-to-right shunting or mixed lesions (e.g. VSD/PDA/CCF) typically present at 1-6 months due to physiological drop in Hb and pulmonary vascular resistance

Differential by colour

• Pink = Heart failure
  • Adequate pulmonary flow, relatively well perfused and oxygenated
  • Shunting lesion
• Grey
  • Shock/circulatory collapse
  • Not enough systemic flow, not oxygenating well
  • Left-sided obstructive, duct-dependent lesions
  • Very sick
  • Almost all benefit from fluids (and prostaglandin if <1 month)
• Blue
  • <1 month: Right obstructive duct-dependent
  • >1 month: Right obstructive duct-dependent or mixing lesion
  • Almost always require prostaglandins

Cyanotic heart disease

• Occurs if:
  • Pulmonary blood flow reduced (e.g. pulmonary atresia)
  • Parallel circuits
  • Overt mixing
• Cyanosis with oligaemia on CXR
  • Stenosis at, below or above the pulmonary valve or by tetralogy of fallot
  • If <1 month:
    • PGE1 infusion (5-25ng/kg/min)
    • FiO2 0.50 gives small increase in O2 delivery
    • Lungs very compliant and any pressures >12-15 reduce lung blood flow further
    • Most will need Blalock-Taussig shunt
  • If >1 month:
    • If PaO2 <30 or cyanotic spells despite fluid resuscitation and oral beta-blockers, urgent Blalock-Taussig shunt required. 
    • Urgent treatment of ToF spells requires high FiO2, knee-chest or legs raised position, N/saline bolus 20mL/kg and IV morphine 0.1mg/kg. 
    • If this fails, esmolol can reduce subpulmonary obstruction. 
    • Inotropes and vasopressors should be avoided

• Cyanosis with pulmonary oedema in newborn
  • TGA, single ventricle, truncus arteriosus, total anomalous pulmonary vein drainage
  • Present with tachypnoea, tachycardia, cardiomegaly and hepatomegaly
  • DDx includes primary lung disease
  • Correct acidaemia and FiO2 should be high
  • Mechanical ventilation and dobutamine helpful
  • PGE1 in all cases except:
    • If small heart on CXR with cyanosis and pulmonary oedema suggesting TAPVD with obstruction of pulmonary veins, in which case PGE1 will exacerbate the problem

PEARLs

• Work of breathing
  • Increased work of breathing often respiratory origin
  • Silent tachypnoea often cardiac or metabolic acidosis
• Neonatal cyanosis
  • CHD
  • Sepsis
  • Respiratory disorders
  • Haemoglobinopathy (polycythaemia, methaemoglobinaemia)
• Central vs. peripheral cyanosis
  • Look inside mouth

History

• Timing of symptoms
  • Respiratory – Starts at birth
  • Cardiac – Days after birth (ductus begins closing)
• Examination
  • Silent dyspnoea – Cardiac or metabolic
  • Overt increased WOB – Respiratory
  • Hepatomegaly (CHF)
    • Liver edge should be <2cm from costal margin
    • Normal liver <8cm in diameter

Investigations

• Hyperoxia test
  • Compare SpO2 before and after 100% O2 for 5-10 minutes (15 min in Cameron)
  • If improves, consider respiratory causes
    • Passed test = PaO2 >250
    • Failed test = PaO2 <100
    • PaO2 100-250 suggests mixed lesion
  • If fails to improve, likely cardiac (shunt)
  • Caution: 100% O2 is a pulmonary vasodilator and could worsen respiratory distress in duct-dependent lesion by decreased PVR and increasing pulmonary flow

• Femoral pulse delay or absence
  • May suggest coarctation of aorta
• Brachial-femoral pulse differential
• Blood pressure differential
  • Preductal (right arm) and lower limb BP differential >10mmHg may suggest coarctation
• O2 saturation differential
  • >3% difference between right arm and right leg, <94% in lower extremities or <90% in any extremity are considered significant

ECG

• LVH at any stage
  • S wave in V1 >98th percentile for age
  • R wave in V6 >98^th percentile for age
  • Cameron
    • S in V1 + r in V6 >30mm to 1 year or >40mm after 1 year
• RVH after 1 month
  • R in V1 >98th percentile for age
  • S wave in V6 >98^th percentile for age
  • Cameron
    • R >S in V1 after 1 week and/or T wave upright in V1 after 1 week
    • S in V6 >15mm at 1 week, 10mm at 6mo and 5mm at 1 year

CXR

• Clear black lung fields = Right heart obstruction
• Cardiomegaly = Left-to-right shunting

CXR

• Boot shaped heart
  • Tetralogy of Fallot 

CXR

• Snowman
  • Total anomalous pulmonary circulation

CXR

• Egg on a string
  • Transposition of the Great Arteries

POCUS

• Is global cardiac function poor?
• Are there four chambers?
• Is the septum intact?

Blood tests

• Glucose
• Electrolytes (?Adrenal insufficiency)
• Septic workup
• Methaemoglobin if cyanosis without respiratory distress
• Ammonia (metabolic panel)
• TSH
• BNP
  • <100 pg/mL has sensitivity 100% and specificity 98%
  • >123.5pg/mL has sensitivity 93% and 100% specificity to detect haemodynamically significant left-to-right shunts
  • >40pg/mL to differentiate cardiac from pulmonary causes has accuracy of 84%

Treatment of grey/blue infants

• Suspicious for duct-dependent lesions
  • Pulmonary atresia/stenosis – Duct shunts left to right to allow pulmonary flow
  • Coarctation of aorta/AS – Duct shunts right to left to allow systemic flow
  • Transposition of the great arteries requires mixing via patent ductus arteriosus sometimes
• Early empirical antibiotics in case of sepsis
• Prostaglandin therapy for any infant <1 month
  • Dose 5-21ng/kg/min
  • Can cause apnoea, fever and hypotension
  • Prepare to intubate and resuscitate
• Judicious fluid therapy
  • 5-10mL/kg to improve preload and encourage duct opening

• Oxygen
  • Target 85%
• Sodium bicarbonate if acidotic as this minimises hypoxic pulmonary vasoconstriction
• Inotropes/vasopressors to maintain systemic and pulmonary perfusion
• Avoid ketamine for induction
  • Increases peripheral vascular resistance and worsens left-to-right shunt, leading to cardiovascular collapse
  • Fentanyl is better choice
• If starting PPV, use low PEEP initially
  • Can increase PVR and decreased SVR and preload

Treatment of pink infants

• Suspicious for paediatric CHF – VSD, ASD, aortic stenosis, PDA + SVT, AV block, cardiomyopathy and myocarditis
• Oxygen therapy ??
  • Potent pulmonary vasodilator and may worsen hypoxaemia
  • Target 85% only
• Fluid restriction (50% maintenance)
• Frusemide
  • Dose
• Inotropes or vasodilators (i.e. milrinone, dobutamine, adrenaline +- norad)
• If femoral pulses absent or aortic stenosis suspected, add prostaglandin E1

Associations (cameron)

• Maternal diabetes
  • Structural heart disease, transient cardiomyopathy
• Maternal lupus
  • Congenital complete heart block
• Maternal teratogens
  • Alcohol = ASD or VSD
  • Amphetamines = VSD, PDA, ASD, TGA
  • Lithium = Ebstein’s abnormality
  • Retinoic acid = Conotruncal abnormalities
  • Valproic acid = ASD, VSD, AS, CoA
• Maternal infections
  • Rubella = PDA and peripheral pulmonary artery stenosis
• FHx
  • Sudden cardiac death = Long QT syndrome
  • Autosomal dominant = HOCM, Supravalvular aortic stenosis, Marfan’s syndrome, idiopathic mitral valve prolapse and some ASD and long QT

Acyanotic defects (Cameron)

• Make up 75% of congenital heart defects
• Left-to-right shunts (increased pulmonary vascular markings on CXR)
  • LVH – VSD, PDA and AVSD
  • RVH – ASD
• No shunting (decreased or normal pulmonary blood flow on CXR)
  • LVH – Aortic stenosis and coarctation of the aorta
  • RVH – Pulmonary stenosis

Ventricular septal defects

• 30% of congenital heart disease
• May be small or large, membraneous or muscular
• Clinical
  • May present with murmur through to CCF
  • Loud, harsh, high-pitched systolic murmur at left sternal border, often with thrill
  • HS normal
  • CXR normal
  • ECG often shows biventricular hypertrophy or at least LVH
• Many small ones close spontaneously but untreated cases can lead to pulmonary hypertension and aortic valve prolapse

Persistent ductus arteriosus

• Pulmonary trunk to aorta with left-to-right shunting after birth
• Clinical
  • Continuous ’machinery’ murmur at upper left sternal edge
  • Soft diastolic component
  • May present with CCF if severe
  • Large lesions will have CXR changes of cardiomegaly, pulmonary plethora and LVH
  • Treatment may involve indomethacin, catheter or ligation

Atrial septal defect

• Usually at fossa ovale (secundum ASD’s)
• Clinical 
  • Ejection systolic murmur in pulmonary area due to increased pulmonary flow
  • Wide fixed splitting of S2
  • Symptoms often mild
  • CXR showed cardiomegaly, pulmonary plethora
  • ECG often showed partial RBBB

Atrioventricular septal defect

• Includes defects low on atrial septum, abutting the AV valves +- ventricular septal defect
• Often cleft MV also
• If severe MR, present with CCF
• If significant ventricular defect coexists (complete AVSD), infants present like large VSD (cardiac failure in early months)
  • Commonest association with Down’s syndrome
• CXR shows cardiomegaly and pulmonary plethora
• ECG shows left axis deviation and partial RBBB

Pulmonary stenosis

• Most common obstructive lesion
• Usually asymptomatic ejection systolic murmur at pulmonary area radiating to the back +- thrill +- ejection click in early systole
• Can present with CCF
• More severe cases may present in infancy with cyanosis due to right-to-left shunting through patent foramen ovale or ASD
• ECG shows RVH in severe cases

Aortic stenosis

• Most present with incidental ejection systolic murmur over aortic area, radiating to the carotids +- thrill +- ejection click at apex
• ECG shows LVH in severe cases
• If critical may present as CCF

Coarctation of the aorta

• Narrowing of aorta near ductus arteriosus
• Often associated bicuspid aortic valve, AS, VSD or mitral valve defects
• May present in early weeks with circulatory collapse or CCF
• Milder cases present with hypertension, murmur or reduced femoral pulses
• Radiofemoral delay only evident once collaterals develop in later years
• Upper vs. lower limb BP >20mmHg difference
• Management requires prostaglandins if presents in infancy to allow flow through ductus arteriosus

Hypoplastic left heart

• Seen with severe AS or coarctation
• Present in shock within days of birth
• Require resuscitation and prostaglandins

Cyanotic cardiac defects

• Account for 25% of lesions
• Cyanotic defects with reduced pulmonary flow
  • RVH – Tetralogy of Fallot, severe pulmonary stenosis
  • LVH – Tricuspid atresia or pulmonary atresia
• Cyanotic defects with increased pulmonary flow
  • RVH
    • TGA (separate circulations), total anomalous pulmonary venous return (TAPVR) or hypoplastic left heart syndrome
  • LVH
    • Truncus arteriosus (bidirectional shunting)

Tetralogy of fallot

• Four components: Pulmonary stenosis, overriding aorta, VSD and RVH
• Right to left shunting occurs across VSD into aorta due to impaired flow through pulmonary valve area
• Cyanosis often mild at birth and increases during infancy with clubbing and failure to thrive
  • Worse with exertion and may suffer Tetralogy spells
• Clinical
  • Systolic murmur maximal at left sternal edge and pulmonary area, radiating to the back
  • Loud single S2 (no pulmonary sound)
  • CXR: Reduced pulmonary vascularity, boot-shaped uptilted apex
  • ECG: RVH

Tetralogy spells

• Occur mostly in infants <6mo and can occur with any agitation
• Likely involves dynamic infundibular obstruction
• Net result is imbalance in pulmonary and systemic flow resulting in hypercyanotic, hypoxic or cyanotic spells
  • Squatting will increase SVR to reduce right-to-left shunting and children may do this of their own accord
• Ix
  • ABG
  • ECG
  • CXR
  • Echo

• Rx
  • Quiet, calm environment. Hold in parents arms to prevent crying and improve pulmonary flow
  • Knee-chest or squatting position is preferred
  • Supplement 100% O2
  • Continuous monitoring
  • Morphine to treat hyperpnoea and abort crying
  • Small volume challenge can be helpful
  • Propranolol IV to block infundibular beta-receptors and lessen RV outflow obstruction
  • Phenylephrine increases SVR to decrease right-to-left shunting
  • Consider bicarbonate correction of acidosis if severe

Persistent truncus arteriosus

• Single artery arises from heart and branches into pulmonary vessels and aorta
• Rare
• Truncal valve sits across large VSD and receives blood from both ventricles
• Cyanosis is mild but CCF appears in the newborn
• CXR shows cardiomegaly and pulmonary plethora
• ECG often normal

Transposition of the great arteries

• Survival possible only if there is flow between independent circuits via patent foramen ovale, ductus arteriosus or septal defect to allow mixing
• Cyanosis marked from birth
• Often forceful RV impulse with no murmur
• CXR often shows increased vascular markings and ’egg on its side’ great vessel silhouette
• ECG often normal
• Urgent balloon atrial septostomy may allow enough mixing

Last Updated on November 10, 2021 by Andrew Crofton