FCPS TOACS · Secundum ASD Mock Test

❓ Q1. Describe the ECG findings.

✅ Model Answer:
• ECG findings: Right axis deviation, rsR' pattern in V1 (minor RV conduction delay), tall R waves in V1, deep S waves in V5-V6, right atrial enlargement (tall peaked P waves).
• Classic pattern: Right axis deviation + rsR' in V1.
• Differentiation: Primum ASD has left axis deviation.

❓ Q2. Explain the pathophysiology of secundum ASD. Why does it cause RV volume overload?

✅ Model Answer:
• Left-to-right shunt because LV is more compliant than RV → blood flows LA → RA.
• Qp:Qs typically 2:1 to 4:1.
• RV volume overload: Increased volume in RA → RV dilation.
• Pulmonary artery pressure usually normal.
• No cyanosis unless Eisenmenger develops.

❓ Q3. Describe the auscultatory findings in secundum ASD. What is the mechanism of the fixed widely split S2?

✅ Model Answer:
• Fixed widely split S2 – hallmark of ASD. Split does not vary with respiration.
• Mechanism: Increased RV stroke volume prolongs RV ejection → pulmonary closure delayed throughout respiratory cycle.
• Systolic ejection murmur at LUSB (increased flow across pulmonary valve).
• Mid-diastolic rumble at LLSB (increased flow across tricuspid valve) – Qp:Qs ≥2:1.

❓ Q4. What are the indications for closure of a secundum ASD?

✅ Model Answer:
• Qp:Qs >1.5:1
• RV enlargement (RVEDV index >120 mL/m²)
• Paradoxical embolism (stroke/TIA)
• Symptoms (exercise intolerance, palpitations)
• Atrial arrhythmias
• Optimal age: 2-4 years.

❓ Q5. What is the transcatheter device used for ASD closure? What are the criteria for device closure?

✅ Model Answer:
• Device: Amplatzer septal occluder (double-disc nitinol mesh).
• Deployed via femoral vein under TEE/ICE guidance.
• Criteria: Secundum ASD, defect ≤38 mm, adequate rims (≥5 mm, especially aortic rim), weight ≥10-15 kg.
• Success rate >95%.
• Post-procedure: aspirin 6 months.

❓ Q6. When is surgical closure preferred over transcatheter closure?

✅ Model Answer:
• Large defects (>38 mm)
• Deficient rims (<5 mm, especially aortic rim)
• Multiple fenestrations
• Primum or sinus venosus ASD
• Failed device closure
• Inadequate vascular access.

❓ Q7. What is the natural history of unrepaired secundum ASD? Why is early closure recommended?

✅ Model Answer:
• Childhood: Usually asymptomatic. Small ASDs may close spontaneously.
• Adulthood: Exercise intolerance, atrial arrhythmias, pulmonary hypertension, right heart failure.
• Early closure: Prevents late complications, improves survival, reduces paradoxical embolism risk.
• Optimal age: 2-4 years.

❓ Q8. A 30-year-old with unrepaired ASD presents with a stroke. What is the mechanism and management?

✅ Model Answer:
• Mechanism: Paradoxical embolism – DVT clot passes from RA to LA through ASD → stroke.
• Management: Acute stroke treatment, anticoagulation (warfarin/DOAC), ASD device closure (regardless of shunt size), evaluate for DVT.

❓ Q9. How does the ECG in secundum ASD differ from that in ostium primum ASD?

✅ Model Answer:
• Secundum ASD: Right axis deviation + rsR' in V1.
• Primum ASD: Left axis deviation (superior QRS axis) + rsR' in V1.
• Primum ASD also has cleft anterior mitral leaflet (MR) and strong association with Down syndrome.
• Primum ASD requires surgical closure + mitral valvuloplasty.

❓ Q10. A child with secundum ASD and first-degree AV block. Family history of ASD in father. What genetic condition should be suspected?

✅ Model Answer:
• NKX2.5 gene mutation – autosomal dominant.
• Features: Familial ASD (secundum or primum) + progressive AV conduction disease (first-degree to complete heart block).
• Management: Genetic testing, annual ECG monitoring, pacemaker if complete heart block develops, family screening.

❓ Q11. A 2-year-old with a small secundum ASD (4 mm) and no RV enlargement. What is the management?

✅ Model Answer:
• Observation with serial echocardiograms.
• Small ASDs (<5-6 mm) have high chance of spontaneous closure in first 2 years.
• Repeat echo at 2-3 years. If defect remains small and no RV enlargement, no intervention needed.
• If still present at school age with RV enlargement → closure indicated.

❓ Q12. A 6-year-old post-ASD device closure presents with chest pain and dyspnea 2 weeks later. Echocardiogram shows pericardial effusion. What is the diagnosis and management?

✅ Model Answer:
• Diagnosis: Device erosion into aorta/atrium – rare (<0.3%).
• Management: Urgent echocardiogram, pericardiocentesis if tamponade, emergency surgical repair to remove device and repair erosion.
• Prevention: Careful patient selection (adequate rims especially aortic rim ≥5 mm).

❓ Q13. An adult with unrepaired secundum ASD presents with cyanosis, clubbing, and loud P2. What is the diagnosis and management?

✅ Model Answer:
• Diagnosis: Eisenmenger syndrome – reversed shunt (right-to-left) due to severe pulmonary hypertension.
• Management: ASD closure is CONTRAINDICATED. Pulmonary vasodilators (bosentan, sildenafil), anticoagulation, heart-lung transplantation for end-stage, avoid pregnancy.

⚕️ FCPS MCPS IMM MD Paediatrics TOACS · Mock Test