Systemic paediatrics: atrioventricular septal defect in Down syndrome: practice question

A Pediatrics question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pediatrics · Systemic paediatrics: atrioventricular septal defect in Down syndrome

Sample item

An infant with Down syndrome has a systolic murmur and early heart failure. ECG shows a superior (left) axis deviation with a prolonged PR interval. Which lesion is most likely?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Complete atrioventricular septal defect

Atrioventricular septal defect is the characteristic cardiac lesion of Down syndrome, from abnormal endocardial cushion development. The conduction tissue is displaced, which causes a superior axis on ECG. Early surgical repair is needed because pulmonary vascular disease develops early in these infants.

Option by option

  • A. Patent ductus arteriosus

    A PDA gives a continuous murmur and does not cause a superior axis.

  • B. Secundum atrial septal defect

    A secundum ASD gives right axis deviation and a right bundle branch pattern.

  • C. Complete atrioventricular septal defect (correct)

    Correct. Superior axis with a prolonged PR in Down syndrome points to an AV septal defect.

  • D. Isolated perimembranous ventricular septal defect

    An isolated VSD does not shift the axis superiorly.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is C, Complete atrioventricular septal defect. Atrioventricular septal defect is the characteristic cardiac lesion of Down syndrome, from abnormal endocardial cushion development.

Why is "Patent ductus arteriosus" not the answer?

A PDA gives a continuous murmur and does not cause a superior axis.

Why is "Secundum atrial septal defect" not the answer?

A secundum ASD gives right axis deviation and a right bundle branch pattern.

Why is "Isolated perimembranous ventricular septal defect" not the answer?

An isolated VSD does not shift the axis superiorly.

What concept does this question test?

It tests Systemic paediatrics: atrioventricular septal defect in Down syndrome in Pediatrics. The conduction tissue is displaced, which causes a superior axis on ECG. Early surgical repair is needed because pulmonary vascular disease develops early in these infants.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Systemic paediatrics: atrioventricular septal defect in Down syndrome?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.