Makindo Medical Notes

⚠️ Because of the high complication rate of permanent pacemaker insertion during the neonatal period, it should be reserved for selected cases only.

ℹ️ About

• 🍼 Rare disorder in newborns – ~1 in 20,000 pregnancies
• 🕐 Onset usually detected between 18–34 weeks gestation
• Represents the most common cause of congenital bradycardia

🧬 Aetiology

• ⚡ Atrophy and fibrosis of the fetal/neonatal AV node
• 🧪 Caused by maternal autoantibodies (anti-Ro/SSA, anti-La/SSB) crossing the placenta → immune-mediated injury
• 🤰 Strong association with maternal autoimmune disease, especially SLE and Sjögren’s syndrome

🩺 Clinical Features

• 👩‍🦰 Mother may have active or latent connective tissue disease (e.g. SLE)
• 🚼 In utero: fetal hydrops, intrauterine death, or congestive heart failure
• 👶 Many infants are asymptomatic at birth
• ⚡ Symptomatic children: syncope, presyncope, poor feeding, or lethargy
• 📉 Long-term: risk of dilated cardiomyopathy, heart failure
• 💀 Risk of Stokes–Adams attacks (transient asystole) or sudden cardiac death if untreated

🔎 Investigations

• 📈 ECG + 24-hour Holter: shows persistent complete heart block (atria and ventricles beating independently)
• 🩻 Echocardiogram: exclude structural congenital heart disease
• 🧪 Maternal serology: check anti-Ro/SSA and anti-La/SSB antibodies
• 📡 Fetal echocardiography during pregnancy for early detection

💊 Management

• 👶 Careful monitoring in neonatal period; watchful waiting if asymptomatic with adequate heart rate
• 🔌 Permanent pacemaker for symptomatic children or those with severe bradycardia
• 💉 Antenatal maternal steroids (e.g. dexamethasone) may reduce progression in selected fetal cases
• 📅 Affects risk in future pregnancies → mothers require close monitoring in subsequent pregnancies

📚 References

• Congenital Complete Heart Block – European Cardiology Review

💊 Case Reports

• 💓 Case 1 – Neonatal Lupus–Associated Heart Block (Age: 2 days): Term infant born to a mother with known systemic lupus erythematosus (anti-Ro/SSA positive). Detected to have persistent bradycardia (HR 50 bpm) shortly after birth, with no structural cardiac abnormality on echocardiography. Investigations: ECG showed complete atrioventricular (AV) dissociation with narrow QRS complexes. Diagnosis: Congenital complete heart block secondary to transplacental passage of maternal autoantibodies damaging the fetal conduction system. Management: Close neonatal monitoring; later required pacemaker implantation at 4 months due to symptomatic bradycardia and poor feeding. Teaching point: Maternal anti-Ro/SSA and anti-La/SSB antibodies can cause irreversible fetal AV nodal fibrosis — early detection by fetal echocardiography enables timely planning for neonatal pacing.
• 🩺 Case 2 – Isolated Congenital Heart Block (Age: 12 years): Previously well child presented with exertional fatigue and dizziness. No maternal autoimmune disease. Pulse rate persistently 45 bpm. Investigations: ECG showed complete heart block with junctional escape rhythm (rate 45 bpm); echocardiogram normal. Diagnosis: Idiopathic congenital complete AV block. Management: Dual-chamber pacemaker insertion with good symptomatic improvement. Teaching point: Isolated congenital complete heart block may present later in childhood due to stable compensatory escape rhythms — pacing is indicated if symptomatic or with ventricular dysfunction.