Heart Failure And Cyanosis In Children Acyanotic And Cyanotic Congenital Heart Disease - Part 1
Congenital heart diseases are classified as acyanotic lesions (e.g., VSD, ASD, PDA) with left-to-right shunts causing heart failure, and cyanotic lesions (e.g., Tetralogy of Fallot, TGA) with right-to-left shunts producing systemic desaturation and cyanosis.
Heart Failure in Children: Acyanotic & Cyanotic Congenital Heart Disease — Part 1
Big Idea: This lecture, delivered by Professor Yiu-fai Cheung (Division of Paediatric Cardiology, HKU), focuses on paediatric heart failure — a fundamentally different entity from adult heart failure. In adults, heart failure is usually caused by myocardial dysfunction (e.g., ischaemic heart disease destroying muscle). In children, the heart muscle is often perfectly normal — the problem is structural congenital heart defects that impose excessive workload (volume or pressure overload) on an otherwise healthy myocardium. This distinction is the conceptual backbone of the entire lecture. [1]
Learning Objectives (from the lecture overview slide):
Concept of 'heart failure' — Important categories of structural congenital heart lesions that cause heart failure in neonates and infants — 'Duct-dependent' systemic circulation — Management of heart failure [1]
How it fits into exams and clinical practice:
- Paediatric CHD is a favourite topic for written papers (MCQ, SAQ, minicase). Questions test your ability to distinguish causes of heart failure by age group (neonate vs infant vs older child), understand the haemodynamics of left-to-right shunts, recognise duct-dependent lesions, and know when to give Prostaglandin E1.
- Clinically, missing a coarctation or duct-dependent lesion in a neonate is catastrophic — the baby collapses when the duct closes.
1. The Concept of Paediatric Heart Failure
"The pathophysiologic state in which the heart fails to pump blood at a rate to meet the demand of the body." [1]
This is a supply vs demand mismatch. The lecture emphasises two distinct mechanisms: [1]
| Mechanism | Explanation | Predominant Age Group |
|---|---|---|
| Dysfunction of the heart | Intrinsic problem with contractility (myocardium itself is sick) | More common in adults; also neonates (myocarditis, cardiomyopathy, ischaemia) and older children |
| Cardiac overload (pressure or volume overload) | Heart muscle contracts normally, but faces an abnormal haemodynamic burden from structural CHD | Much more common in children |
Key Conceptual Point — The Patient A vs Patient B Slide
The lecture opens with echocardiograms of two patients. Patient A has excellent contractility. Patient B has poor contractility. Intuitively, you'd say Patient B has heart failure. But BOTH have heart failure symptoms. This demonstrates that impaired contractility is not the only cause of heart failure — in children, structural lesions causing overload produce heart failure despite normal systolic function. [1][2]
Why this matters from first principles:
- In an adult with IHD, myocytes die → contractility drops → forward failure + backward congestion.
- In a baby with a large VSD, the heart muscle is fine, but blood keeps shunting left-to-right → pulmonary overcirculation → volume overloads the LA and LV → heart failure despite normal or even hyperdynamic contraction.
In adults, heart failure is predominantly due to dysfunction of the heart. In children, heart failure is predominantly due to overloading of the heart. [1]
This is a crucial exam discriminator. If asked "What is the most common mechanism of heart failure in paediatric patients?", the answer is volume/pressure overload from congenital structural heart defects, not myocardial dysfunction.
2. Clinical Presentation: How Do Infants and Children with Heart Failure Present?
Breathlessness, especially on exertion — Poor feeding — Excessive sweating — Failure to thrive — Recurrent chest infection — Exercise incapacity in older children [1]
Why each symptom occurs — explained from first principles:
| Symptom | Mechanism | Clinical Correlation |
|---|---|---|
| Breathlessness on exertion | Pulmonary congestion from elevated LA pressure → interstitial oedema → reduced lung compliance → increased work of breathing | In infants, "exertion" = feeding. A baby who takes 20 minutes to finish 30 mL of milk and gets breathless is "exerting" maximally |
| Poor feeding | Combination of breathlessness during feeds + increased metabolic demand + splanchnic hypoperfusion | Infants cannot tell you they're breathless; they just stop feeding or take very small volumes |
| Excessive sweating | Sympathetic activation (compensatory mechanism to maintain CO) → diaphoresis, especially during feeds | Sweating during feeds is a classic history clue in paediatric heart failure |
| Failure to thrive | Increased metabolic demand from tachycardia + tachypnoea + poor caloric intake (feeds poorly) → negative energy balance | Weight faltering is often the presenting complaint that leads to discovery of CHD |
| Recurrent chest infections | Pulmonary overcirculation (in L-to-R shunts) → pulmonary congestion → impaired mucociliary clearance → predisposition to lower respiratory infections | A baby with "recurrent pneumonia" should be investigated for underlying CHD |
| Exercise incapacity | Relevant for older children; inability to keep up with peers during sports | Less relevant in infancy since infants don't exercise formally |
2.2 Signs (Physical Examination)
The lecture categorises signs into three groups: [1]
Tachypnoea — Subcostal insucking — Wheezing in infants [1]
| Sign | Why It Happens |
|---|---|
| Tachypnoea | Elevated LA pressure → increased pulmonary venous pressure → transudation into interstitium → stiff lungs → compensatory rapid shallow breathing |
| Subcostal insucking (retractions) | Increased work of breathing against non-compliant, congested lungs → accessory muscle use. In infants, the chest wall is very compliant, so retractions are prominent |
| Wheezing in infants | Bronchial oedema from pulmonary congestion + compression of small airways by distended pulmonary vessels. This is often mistaken for "bronchiolitis" or "asthma" — a classic trap! |
Common Trap — Cardiac Wheeze Mimicking Respiratory Disease
Hepatomegaly — Distension of neck veins (not obvious in small children) — Peripheral oedema (rare in the absence of cardiac dysfunction) [1]
| Sign | Why It Differs From Adults |
|---|---|
| Hepatomegaly | The most reliable sign of right-sided or biventricular failure in infants and children. The liver edge should normally be ≤1–2 cm below the costal margin in children < 2–3 years. Anything beyond this in the context of tachypnoea and tachycardia = heart failure until proven otherwise [3] |
| JVP distension | Anatomically difficult to assess in infants because of short, fat necks. Not a reliable sign in small children [1] |
| Peripheral oedema | Rare in the absence of cardiac dysfunction [1]. In children with structural overload (e.g., large VSD), peripheral oedema is uncommon. If you see significant peripheral oedema in a child with heart failure, think about myocardial dysfunction (myocarditis, cardiomyopathy) or nephrotic syndrome |
Tachycardia — Cardiomegaly [1]
- Tachycardia: Sympathetic activation → increased heart rate to maintain cardiac output (CO = HR × SV). This is one of the earliest signs.
- Cardiomegaly: Chronic volume overload → ventricular dilation (Frank-Starling mechanism) → the heart enlarges to accommodate increased preload. Detectable on CXR (cardiothoracic ratio > 0.6 in infants, > 0.55 in older children) and on palpation (displaced apex beat).
Cool extremities — Prolonged capillary refill — Decreased pulse volume — These signs are unusual, only when decompensated [1]
Why this is "unusual": In most paediatric heart failure from structural overload, compensatory mechanisms (tachycardia, ventricular dilation, sympathetic drive) maintain forward output for a long time. It's only when these mechanisms are overwhelmed — or when the duct closes in duct-dependent lesions — that you get frank low cardiac output.
When you DO see these signs, the child is critically ill and needs urgent intervention.
3. Causes of Paediatric Heart Failure — Organised by Age
This is the core organisational framework of the lecture. The aetiology differs dramatically by age:
1) Left ventricular outflow tract obstruction — 2) Myocardial dysfunction — 3) Abnormalities of heart rate or rhythm — 4) Extra-cardiac causes [1]
| Category | Specific Causes | Key Features |
|---|---|---|
| LVOT obstruction | Coarctation of the aorta, Interrupted aortic arch, Critical aortic stenosis, Aortic atresia (HLHS) [1] | Present in first days of life when ductus arteriosus closes → sudden loss of systemic perfusion → shock |
| Myocardial dysfunction | Transient myocardial ischaemia, Myocarditis, Cardiomyopathy [1] | These cause true pump failure with reduced contractility |
| Abnormal heart rate | Supraventricular tachycardia (SVT), Complete heart block (CHB) [1] | SVT: rate too fast → inadequate diastolic filling → ↓CO. CHB: rate too slow → ↓CO despite normal SV |
| Extra-cardiac causes | Sepsis, Asphyxia, Hypocalcaemia, Anaemia [1] | Systemic disturbances causing secondary ventricular dysfunction. Sepsis → myocardial depressant factors. Asphyxia → myocardial ischaemia. Hypocalcaemia → impaired excitation-contraction coupling |
Why Hypocalcaemia Causes Heart Failure
3.2 Left Ventricular Outflow Tract (LVOT) Obstruction — In Detail
This section is extensively covered in the lecture and is extremely high-yield.
1) Coarctation or interruption of the aorta — 2) Critical aortic stenosis — 3) Aortic atresia (hypoplastic left heart syndrome) [1]
Coarctation of the aorta is a localised narrowing of the aorta, typically at or near the site of the ductus arteriosus (juxtaductal). [1]
Haemodynamics from first principles:
- In utero: The ductus arteriosus is open → blood bypasses the coarctation via the duct → baby is fine.
- After birth: The ductus begins to close (physiologically by day 1–2) → the narrow segment is now the only pathway for systemic blood flow to the lower body → if the coarctation is severe ("critical"), the LV cannot push blood past it → acute LV failure + lower body ischaemia.
Presentation:
- Days 2–7 of life (as duct closes): shock, poor perfusion, weak/absent femoral pulses, metabolic acidosis, oliguria/anuria
- Upper limb hypertension with lower limb hypotension (4-limb BP discrepancy)
Importance of pulse examination — Femoral pulse in particular [1]
MUST-KNOW Clinical Sign
Weak or absent femoral pulses in the presence of palpable upper limb pulses = coarctation of the aorta until proven otherwise. The femoral pulse MUST be palpated in every neonatal examination — it may be the ONLY sign of CoA. Radio-femoral delay is usually NOT detectable in neonates because of the short aorta and fast heart rate. [1][3]
Interrupted aortic arch is the most severe form of aortic arch obstruction — there is a complete discontinuity in the aortic arch. [1]
- The lower body is entirely dependent on the ductus arteriosus for systemic blood flow.
- When the duct closes → catastrophic circulatory collapse.
- Often associated with DiGeorge syndrome (22q11 deletion) — look for associated features.
Critical aortic stenosis — the aortic valve cusps are thickened and fused, creating severe obstruction to LV outflow from birth. [1]
- If severe enough, the LV cannot generate adequate systemic output → LV failure → duct-dependent systemic circulation.
- Management: balloon dilation (catheter-based) or surgical repair. [1]
Aortic atresia (Hypoplastic Left Heart Syndrome) — the left ventricle, mitral valve, and aortic valve are severely underdeveloped or atretic. [1]
- There is essentially no functional left ventricle → the entire systemic circulation depends on the RV pumping blood through the PDA to the systemic circuit.
- When the duct closes → immediate circulatory collapse and death without intervention.
- Management: staged surgical palliation (Norwood procedure) or heart transplantation.
Concept of 'ductal-dependent systemic circulation' — Prostaglandin E1/E2 [1]
This is one of the most important concepts in paediatric cardiology for exams and clinical practice.
What does "duct-dependent systemic circulation" mean?
- In lesions where the LVOT is critically obstructed (CoA, IAA, critical AS, HLHS), the lower body (and sometimes the entire systemic circulation) receives blood flow via the ductus arteriosus — blood travels from the pulmonary artery → through the PDA → into the descending aorta.
- If the duct closes (which it naturally does within 24–48 hours after birth), systemic perfusion is lost → shock, organ failure, death.
Management — Prostaglandin E1 (PGE1) / E2 (PGE2):
- PGE1 (alprostadil) or PGE2 (dinoprostone) maintain ductal patency by relaxing the smooth muscle of the ductus arteriosus.
- This is a life-saving bridge while the baby is stabilised and prepared for corrective surgery or catheter intervention.
| Feature | Details |
|---|---|
| Drug | PGE1 (IV infusion) or PGE2 |
| Mechanism | Relaxes ductal smooth muscle → prevents/reverses ductal closure |
| Side effects | Apnoea (important — may need ventilatory support), fever, diarrhoea, jitteriness, flushing |
| When to give | Any neonate presenting with shock + absent femoral pulses → suspect duct-dependent lesion → start PGE immediately, even before definitive diagnosis |
Differential cyanosis and clubbing in duct-dependent systemic circulation:
- In CoA/IAA with PDA: the upper body receives oxygenated blood from the LV via the aortic arch. The lower body receives mixed (deoxygenated) blood via the PDA from the RV.
- Result: upper body pink, lower body cyanotic = differential cyanosis. [6][3]
- Over time (if chronic), differential clubbing develops (toes but not fingers).
3.4 Heart Failure in Infants (Weeks to Months of Life)
Large left-to-right shunts: Ventricular septal defect, Atrioventricular septal defect, Persistent arterial duct [1]
Later onset of symptoms (as compared to left ventricular outflow obstructive lesions) [1]
Why is the onset later?
- At birth, pulmonary vascular resistance (PVR) is high (similar to systemic vascular resistance) → even with a structural defect allowing communication between systemic and pulmonary circulations, there is little net shunt.
- Over the first 2–3 months of life, PVR falls physiologically (as the thick-walled fetal pulmonary arterioles remodel) → the pressure difference between the systemic and pulmonary circuits widens → blood shunts left-to-right through the defect → pulmonary overcirculation → heart failure symptoms emerge.
- This is why babies with large VSDs or PDAs typically present at 6–8 weeks of age with symptoms of heart failure, not at birth.
Increased pulmonary blood flow → Increased pulmonary venous return → Volume overloading of left atrium and left ventricle (except atrial septal defect) [1]
Step-by-step mechanism:
- Blood shunts from left (high pressure) to right (low pressure) through the defect
- Pulmonary blood flow increases (Qp:Qs ratio rises above 1:1)
- More blood returns to the left atrium via pulmonary veins
- LA and LV become volume-overloaded → LA dilation, LV dilation
- Increased LV end-diastolic pressure → elevated LA pressure → pulmonary venous congestion → pulmonary oedema → tachypnoea, feeding difficulties, failure to thrive
- If uncorrected: chronic pulmonary overcirculation → pulmonary vascular disease → irreversible pulmonary hypertension → Eisenmenger syndrome (reversal of shunt)
VSD is the most common congenital heart defect (~30% of all CHD). [5]
- Small VSD: Restrictive → small shunt → loud pansystolic murmur (high-velocity jet) → usually asymptomatic → may close spontaneously
- Large VSD: Non-restrictive → large L-to-R shunt → heart failure by 6–8 weeks → soft or mid-systolic murmur (low-velocity, wide-open defect) → requires surgical closure
AVSD involves a defect in the endocardial cushion → single AV valve spanning both ventricles + atrial and ventricular level communication. [1]
- Strongly associated with Down syndrome (trisomy 21)
- Complete AVSD: both atrial and ventricular components + common AV valve → large L-to-R shunt + AV valve regurgitation → early heart failure
- Management: surgical repair at 3–6 months [5]
Persistent arterial duct (PDA) = failure of the ductus arteriosus to close after birth. [1]
- Blood shunts from aorta (high pressure) to pulmonary artery (low pressure) → pulmonary overcirculation
- Classic murmur: continuous "machinery" murmur at the left infraclavicular area
- Common in premature infants and associated with congenital rubella
- Management: indomethacin/ibuprofen (promotes closure in premature infants by inhibiting prostaglandin synthesis) or surgical ligation/device closure [5]
ASD is an uncommon cause of heart failure in infancy and childhood — volume overloading of the right atrium and right ventricle [1]
Shunting from LA to RA → Increased flow through tricuspid valve during diastole → Volume overloading of right ventricle [1]
Why is ASD different?
- In VSD/AVSD/PDA, the shunt volume-loads the left heart (LA and LV).
- In ASD, the shunt goes from LA → RA → RV → pulmonary artery. The left heart is NOT volume-overloaded; it is the right heart that bears the burden.
- Because the RV is very compliant, it can accommodate the extra volume for years or decades without symptoms → hence ASD rarely causes heart failure in childhood.
- ASD typically presents in adulthood (30s–40s) with symptoms or is discovered incidentally as a fixed split S2 + soft ejection systolic murmur at LUSB.
| Lesion | Chamber Overloaded | Timing of HF |
|---|---|---|
| VSD, AVSD, PDA | LA + LV | 6–8 weeks (when PVR falls) |
| ASD | RA + RV | Rarely in childhood; usually adulthood |
Myocardial disease: Myocarditis, Cardiomyopathy (primary, secondary) — Unoperated structural heart defects — Certain repaired or palliated congenital heart defects [1]
In older children, the spectrum shifts back toward myocardial dysfunction being a more common cause:
| Cause | Examples |
|---|---|
| Myocarditis | Viral (Coxsackie B, adenovirus), post-infectious |
| Primary cardiomyopathy | Dilated, hypertrophic, restrictive |
| Secondary cardiomyopathy | Iron overload (thalassaemia major), post-chemotherapy (anthracyclines), neuromuscular disease (Duchenne muscular dystrophy) |
| Unoperated CHD | Late presentation of previously unrecognised defects |
| Repaired/palliated CHD | Ventricular dysfunction after surgery (e.g., systemic RV in Fontan circulation) |
4. Management of Paediatric Heart Failure
1) Identification of the cause and precipitating factors — 2) Tackling of precipitating factors — 3) General supportive management — 4) Medical therapy of heart failure (diuretics, digoxin, ACEI, carvedilol) — 5) Treatment of underlying cause, if possible, by surgical or catheter intervention — 6) Mechanical circulatory support and heart transplantation [1]
| Step | Details |
|---|---|
| 1. Identify cause | History, examination, CXR, ECG, echocardiogram |
| 2. Tackle precipitating factors | Treat infection, correct anaemia, address arrhythmia, correct electrolytes |
| 3. General supportive | Fluid restriction, nutritional support (high-calorie feeds via NG if needed), oxygen, positioning |
| 4. Medical therapy | Diuretics (frusemide — reduce preload/congestion), Digoxin (positive inotrope + rate control), ACE inhibitors (captopril/enalapril — reduce afterload, counteract RAAS), Carvedilol (beta-blocker — reduce sympathetic drive, improve remodelling) |
| 5. Definitive treatment | Surgical repair (e.g., VSD closure, CoA repair) or catheter intervention (e.g., balloon dilation of critical AS, device closure of ASD/PDA) |
| 6. Advanced therapies | ECMO, ventricular assist device (VAD), heart transplantation |
Initial stabilisation by PGE1/E2 → Corrective surgery or catheter intervention [1]
Surgical closure of VSD and PDA — Device closure of ASD and PDA [1]
| Method | Applicable Lesions | Details |
|---|---|---|
| Surgical closure | VSD, PDA, AVSD | Open-heart surgery with CPB; gold standard for large defects |
| Device closure (catheter-based) | Suitable ASD (secundum type), suitable PDA | Less invasive, shorter recovery; not suitable for all defects (e.g., primum ASD requires surgical repair) |
4.4 Mechanical Circulatory Support
ECMO [1] — Provides temporary cardiopulmonary support. Used as a bridge to recovery or bridge to transplantation in acute, potentially reversible causes of heart failure (e.g., fulminant myocarditis, post-cardiotomy failure).
Ventricular Assist Device — Concept of Bridging [1]
- VADs mechanically augment ventricular output.
- Used as a bridge to transplantation (keeps the child alive while waiting for a donor heart) or bridge to recovery (supports the ventricle while myocardial function recovers, e.g., in myocarditis).
5. Integration with Related Material
From supporting sources, the overall classification of CHD by physiology is useful for context: [5][6][7]
| Category | Physiology | Examples |
|---|---|---|
| Acyanotic — L-to-R shunts | Volume overload → HF at 2–3 months | VSD, ASD, PDA, AVSD |
| Acyanotic — Outflow obstruction (sick neonate) | Pressure overload → shock when duct closes | CoA, critical AS, HLHS, IAA |
| Acyanotic — Outflow obstruction (well child) | Mild-moderate obstruction | PS, mild AS |
| Cyanotic — R-to-L shunts | Decreased pulmonary flow → cyanosis | TOF, PA, critical PS |
| Cyanotic — Common mixing | Mixing of oxygenated and deoxygenated blood | TGA, TAPVD, truncus arteriosus, univentricular heart |
Though primarily covered in Part 2, it connects to this lecture:
- Method: 100% O₂ for 10 minutes → measure PaO₂ from right radial artery
- Respiratory cause: PaO₂ usually > 15 kPa
- Cardiac cause: PaO₂ remains low
- Caveat: No longer routinely performed because high FiO₂ can promote ductal closure in duct-dependent circulation → potentially dangerous. Bedside echocardiography is preferred. [6][3]
- Central cyanosis becomes clinically apparent when deoxygenated Hb > 5 g/dL (SaO₂ ≤ 85%)
- Anaemia can mask cyanosis (insufficient total Hb to produce 5 g/dL of reduced Hb)
- Polycythaemia can exaggerate cyanosis [6]
| Syndrome | Associated CHD |
|---|---|
| Down syndrome (trisomy 21) | AVSD, VSD |
| Turner syndrome (45,X) | CoA, bicuspid AV |
| DiGeorge syndrome (22q11.2 del) | IAA, TOF, truncus arteriosus |
| Williams syndrome | Supravalvular AS |
| Noonan syndrome | ASD, PS |
| Marfan syndrome | MR, AR, MVP |
| Congenital rubella | PDA |
| Maternal SLE (anti-Ro/La antibodies) | Congenital complete heart block |
6. Exam Intelligence
| Question Type | Example Stem |
|---|---|
| MCQ | A 5-day-old neonate presents with poor feeding, tachypnoea, and absent femoral pulses. What is the most likely diagnosis? → Coarctation of the aorta |
| MCQ | Which of the following congenital heart defects causes volume overloading of the RIGHT ventricle? → ASD (not VSD, which overloads the LV) |
| SAQ | Describe the concept of duct-dependent systemic circulation and explain the role of PGE1 |
| SAQ | List 4 causes of heart failure in neonates |
| Minicase | A 6-week-old infant presents with tachypnoea, excessive sweating during feeds, and failure to thrive. On examination: tachycardia, hepatomegaly, pansystolic murmur at LLSB. Discuss the most likely diagnosis and management → Large VSD with heart failure |
| OSCE | Demonstrate palpation of femoral pulses in a neonate and explain why |
Common Exam Traps
- Confusing the timing of presentation: LVOT obstruction → presents in first days of life (duct-dependent). Large L-to-R shunts → present at 6–8 weeks (after PVR drops).
- Assuming ASD causes heart failure in childhood: ASD is an uncommon cause of heart failure in infancy and childhood — it overloads the RV, which tolerates volume well.
- Forgetting to check femoral pulses: This is the ONLY reliable sign of CoA in neonates. Radio-femoral delay is NOT detectable.
- Confusing peripheral oedema with paediatric heart failure: Peripheral oedema is rare in the absence of cardiac dysfunction in children — it suggests myocardial disease, not just structural overload.
- Giving high-flow O₂ to a duct-dependent neonate: This can promote ductal closure → worsen shock.
| Feature | VSD | ASD | PDA |
|---|---|---|---|
| Chamber overloaded | LA + LV | RA + RV | LA + LV |
| Timing of HF | 6–8 weeks | Rarely childhood | 6–8 weeks |
| Classic murmur | Pansystolic at LLSB | Fixed split S2 + ESM at LUSB | Continuous machinery murmur at left infraclavicular |
| Spontaneous closure | Small ones can | No (except PFO) | Indomethacin/ibuprofen in prems |
-
Q: A 3-day-old neonate presents with poor perfusion, absent femoral pulses, and metabolic acidosis. What is the most likely diagnosis and immediate management?
- A: Coarctation of the aorta (duct-dependent systemic circulation). Immediate PGE1 infusion to reopen/maintain the ductus arteriosus → stabilise → surgical repair.
-
Q: Why does heart failure from a large VSD present at 6–8 weeks rather than at birth?
- A: At birth, PVR is high → minimal L-to-R shunt. Over the first weeks, PVR falls physiologically → increasing L-to-R shunt → pulmonary overcirculation → volume overload of LA/LV → heart failure symptoms.
-
Q: Compare the chamber overloaded in ASD vs VSD.
- A: ASD → RA and RV (shunt is LA→RA). VSD → LA and LV (shunt causes increased pulmonary venous return to LA/LV).
-
Q: List 4 causes of heart failure in neonates.
- A: (i) LVOT obstruction (CoA, critical AS, HLHS, IAA), (ii) Myocardial dysfunction (myocarditis, cardiomyopathy, transient ischaemia), (iii) Arrhythmia (SVT, CHB), (iv) Extra-cardiac (sepsis, asphyxia, hypocalcaemia, anaemia).
-
Q: What is the medical therapy for paediatric heart failure?
- A: Diuretics (frusemide), Digoxin, ACE inhibitors (captopril/enalapril), Carvedilol (beta-blocker). Plus treatment of the underlying cause.
-
Q: A baby with Down syndrome presents at 4 weeks with heart failure. What CHD should you suspect?
- A: AVSD (atrioventricular septal defect) — strongly associated with trisomy 21.
High Yield Summary
Paediatric heart failure is fundamentally different from adult heart failure. In children, the most common mechanism is cardiac overload from congenital structural defects (volume or pressure overload), NOT myocardial dysfunction.
Age-based causes:
- Neonates: LVOT obstruction (CoA, IAA, critical AS, HLHS) → duct-dependent → PGE1; myocardial dysfunction; arrhythmia; extra-cardiac causes
- Infants (6–8 weeks): Large L-to-R shunts (VSD, AVSD, PDA) as PVR falls
- Older children: Myocardial disease (myocarditis, cardiomyopathy), unoperated/repaired CHD
Key clinical points:
- Cardinal triad in infants: tachypnoea + tachycardia + hepatomegaly
- Always check femoral pulses — absent = CoA until proven otherwise
- ASD rarely causes heart failure in childhood (overloads RV, not LV)
- Peripheral oedema is rare without cardiac dysfunction
- Wheezing in infants can be cardiac, not respiratory
Management: Identify cause → treat precipitating factors → supportive care → medical therapy (diuretics, digoxin, ACEI, carvedilol) → surgical/catheter intervention → ECMO/VAD/transplant if refractory.
Emergency: Duct-dependent systemic circulation → PGE1 immediately → do not wait for echo.
Active Recall - Lecture Notes
[1] Lecture slides: GC 147. Heart failure and cyanosis in children acyanotic and cyanotic congenital heart disease - Part 1.pdf (all slides p1–p43) [2] Paediatrics lecture notes: Block C - Heart failure and cyanosis in children: acyanotic and cyanotic congenital heart disease.pdf (p1) [3] Senior notes: Adrian Lui Pediatrics Notes.pdf (p185, p197) [4] Paediatrics lecture notes: Evaluation of wheezing in infants and children - UpToDate.pdf [5] Senior notes: Maksim Paediatric Notes.pdf (p55–p60) [6] Senior notes: MBBS Final MB (Pediatrics) (Felix PY Lai).pdf (p267, p279, p290) [7] Senior notes: Ryan Ho Cardiology.pdf (p184, p186, p187)
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