⚕️ FCPS MCPS IMM MD Paediatrics TOACS · Mock Test
ECG Interpretation · 8-Minute Observed Station
📚 paeds.online
⏱️ TIME REMAINING
08:00
❓ Q1. Describe the ECG findings.
✅ Model Answer:
• ECG findings: Left axis deviation (superior QRS axis, -90 to -180°), counterclockwise inscription, rsR' in V1 (RV conduction delay), Q waves in I and aVL, right atrial enlargement.
• Pathognomonic: Left axis deviation (superior QRS axis) – distinguishes primum from secundum ASD (which has right axis deviation).
• ECG findings: Left axis deviation (superior QRS axis, -90 to -180°), counterclockwise inscription, rsR' in V1 (RV conduction delay), Q waves in I and aVL, right atrial enlargement.
• Pathognomonic: Left axis deviation (superior QRS axis) – distinguishes primum from secundum ASD (which has right axis deviation).
❓ Q2. What is the pathophysiology of ostium primum ASD? What are the anatomical abnormalities?
✅ Model Answer:
• Anatomy: Primum ASD (lower atrial septum) + cleft anterior mitral leaflet (MR) + intact ventricular septum.
• Hemodynamics: Left-to-right shunt (LA → RA → RV → PA), mitral regurgitation (due to cleft) → LA volume overload.
• Associated with Down syndrome (40-50%).
• Anatomy: Primum ASD (lower atrial septum) + cleft anterior mitral leaflet (MR) + intact ventricular septum.
• Hemodynamics: Left-to-right shunt (LA → RA → RV → PA), mitral regurgitation (due to cleft) → LA volume overload.
• Associated with Down syndrome (40-50%).
❓ Q3. How do you differentiate ostium primum ASD from secundum ASD clinically and on ECG?
✅ Model Answer:
• ECG: Primum = left axis deviation (superior QRS axis). Secundum = right axis deviation.
• Physical exam: Primum has apical holosystolic murmur (MR) in addition to fixed split S2 and LUSB systolic murmur.
• Down syndrome: Strong association with primum (40-50%).
• ECG: Primum = left axis deviation (superior QRS axis). Secundum = right axis deviation.
• Physical exam: Primum has apical holosystolic murmur (MR) in addition to fixed split S2 and LUSB systolic murmur.
• Down syndrome: Strong association with primum (40-50%).
❓ Q4. This child has Down syndrome. What is the association between Down syndrome and AVSD? What other cardiac defects are common?
✅ Model Answer:
• 40-50% of Down syndrome patients have CHD. AVSD is the most common (40% of CHD).
• Other defects: VSD (30%), PDA (10%), TOF (5%), secundum ASD (5%).
• All newborns with Down syndrome should have an echocardiogram.
• 40-50% of Down syndrome patients have CHD. AVSD is the most common (40% of CHD).
• Other defects: VSD (30%), PDA (10%), TOF (5%), secundum ASD (5%).
• All newborns with Down syndrome should have an echocardiogram.
❓ Q5. Describe the auscultatory findings in ostium primum ASD. What is the significance of the apical holosystolic murmur?
✅ Model Answer:
• Auscultation: Fixed widely split S2 (hallmark), systolic ejection murmur at LUSB (increased pulmonary flow), apical holosystolic murmur (mitral regurgitation from cleft mitral valve).
• Apical holosystolic murmur indicates MR – requires surgical repair (mitral valvuloplasty).
• Auscultation: Fixed widely split S2 (hallmark), systolic ejection murmur at LUSB (increased pulmonary flow), apical holosystolic murmur (mitral regurgitation from cleft mitral valve).
• Apical holosystolic murmur indicates MR – requires surgical repair (mitral valvuloplasty).
❓ Q6. What are the echocardiographic findings in ostium primum ASD? What is the gooseneck deformity?
✅ Model Answer:
• Echo: Primum ASD, cleft anterior mitral leaflet with MR, RV volume overload, normal ventricular septum.
• Gooseneck deformity: Abnormal elongation and narrowing of LVOT – hallmark of AVSD, may lead to subaortic stenosis.
• Echo: Primum ASD, cleft anterior mitral leaflet with MR, RV volume overload, normal ventricular septum.
• Gooseneck deformity: Abnormal elongation and narrowing of LVOT – hallmark of AVSD, may lead to subaortic stenosis.
❓ Q7. What is the management of ostium primum ASD? When is surgical repair indicated?
✅ Model Answer:
• Management: Surgical repair (patch closure of ASD + mitral valvuloplasty). Transcatheter closure is NOT possible.
• Indications: Qp:Qs >1.5:1, RV enlargement, significant MR, symptoms.
• Timing: 1-2 years of age.
• Management: Surgical repair (patch closure of ASD + mitral valvuloplasty). Transcatheter closure is NOT possible.
• Indications: Qp:Qs >1.5:1, RV enlargement, significant MR, symptoms.
• Timing: 1-2 years of age.
❓ Q8. What is the surgical approach for ostium primum ASD repair? What are the risks?
✅ Model Answer:
• Surgery: Patch closure of primum ASD + suture of cleft mitral leaflet (valvuloplasty).
• Risks: Complete heart block (1-2%, requires pacemaker), residual MR (5-10% require reoperation), subaortic stenosis, arrhythmias.
• Surgery: Patch closure of primum ASD + suture of cleft mitral leaflet (valvuloplasty).
• Risks: Complete heart block (1-2%, requires pacemaker), residual MR (5-10% require reoperation), subaortic stenosis, arrhythmias.
❓ Q9. What are the long-term complications after ostium primum ASD repair?
✅ Model Answer:
• Complications: MR (5-10% reoperation), subaortic stenosis (5%), complete heart block (1-2%), arrhythmias (atrial flutter/fibrillation), residual shunt.
• Lifelong cardiology follow-up required.
• Complications: MR (5-10% reoperation), subaortic stenosis (5%), complete heart block (1-2%), arrhythmias (atrial flutter/fibrillation), residual shunt.
• Lifelong cardiology follow-up required.
❓ Q10. Can ostium primum ASD be closed with a transcatheter device? Why or why not?
✅ Model Answer:
• No, transcatheter closure is NOT suitable.
• Reasons: proximity to AV valves and conduction system (risk of heart block), cleft mitral valve requires surgical repair, inadequate rims for device anchoring.
• No, transcatheter closure is NOT suitable.
• Reasons: proximity to AV valves and conduction system (risk of heart block), cleft mitral valve requires surgical repair, inadequate rims for device anchoring.
❓ Q11. This child is 5 years old and asymptomatic. Is there a risk of pulmonary hypertension? When does it develop?
✅ Model Answer:
• Risk of PH: Less common than complete AVSD, but can develop if large shunt or significant MR. Down syndrome patients may develop PH earlier.
• Early repair (1-2 years) prevents pulmonary vascular disease.
• Risk of PH: Less common than complete AVSD, but can develop if large shunt or significant MR. Down syndrome patients may develop PH earlier.
• Early repair (1-2 years) prevents pulmonary vascular disease.
❓ Q12. What is the differential diagnosis of ostium primum ASD? What other conditions can cause left axis deviation on ECG?
✅ Model Answer:
• Differential: Secundum ASD (right axis), tricuspid atresia (left axis + cyanosis), complete AVSD (primum ASD + VSD + common AV valve).
• Other causes of left axis deviation: left anterior fascicular block, post-surgical.
• Differential: Secundum ASD (right axis), tricuspid atresia (left axis + cyanosis), complete AVSD (primum ASD + VSD + common AV valve).
• Other causes of left axis deviation: left anterior fascicular block, post-surgical.
❓ Q13. A 10-year-old with repaired primum ASD presents with a systolic ejection murmur at LUSB and a new systolic thrill. Echocardiogram shows a gradient of 60 mmHg across the LVOT. What is the diagnosis and management?
✅ Model Answer:
• Diagnosis: Subaortic stenosis – complication of primum ASD repair (gooseneck deformity or fibrous ridge).
• Management: Surgical resection of subaortic membrane (myectomy/membranectomy). Monitor for recurrence.
• Diagnosis: Subaortic stenosis – complication of primum ASD repair (gooseneck deformity or fibrous ridge).
• Management: Surgical resection of subaortic membrane (myectomy/membranectomy). Monitor for recurrence.
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