Cardiology: atrial septal defect: practice question

A General Medicine 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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General Medicine · Cardiology: atrial septal defect

Sample item

A 20-year-old woman has mild exertional dyspnoea. Examination shows a wide, fixed split of the second heart sound and a soft ejection systolic murmur in the pulmonary area. ECG shows sinus rhythm with incomplete right bundle branch block and left axis deviation. What is the most likely lesion?

ASmall restrictive ventricular septal defectBIsolated pulmonary valve stenosisCOstium secundum atrial septal defectDOstium primum atrial septal defect

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

The answer and the reasoning

D. Ostium primum atrial septal defect

Both secundum and primum atrial septal defects cause a fixed split S2 and right ventricular volume overload with RBBB. The axis separates them: secundum defects give right axis deviation, whereas an ostium primum defect, which is an atrioventricular septal defect with a cleft mitral leaflet, gives left axis deviation (superior axis).

Option by option

A. Small restrictive ventricular septal defect
A small VSD causes a loud pansystolic murmur at the left sternal edge without a fixed split.
B. Isolated pulmonary valve stenosis
Pulmonary stenosis causes a loud ejection click and murmur with a soft, delayed P2, and the split is not fixed.
C. Ostium secundum atrial septal defect
Secundum defects, the most common type, are associated with right axis deviation instead.
D. Ostium primum atrial septal defect (correct)
Left axis deviation with incomplete RBBB points to the primum type, which sits low in the septum.

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.

Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is D, Ostium primum atrial septal defect. Both secundum and primum atrial septal defects cause a fixed split S2 and right ventricular volume overload with RBBB.

Why is "Small restrictive ventricular septal defect" not the answer?

A small VSD causes a loud pansystolic murmur at the left sternal edge without a fixed split.

Why is "Isolated pulmonary valve stenosis" not the answer?

Pulmonary stenosis causes a loud ejection click and murmur with a soft, delayed P2, and the split is not fixed.

Why is "Ostium secundum atrial septal defect" not the answer?

Secundum defects, the most common type, are associated with right axis deviation instead.

What concept does this question test?

It tests Cardiology: atrial septal defect in General Medicine. The axis separates them: secundum defects give right axis deviation, whereas an ostium primum defect, which is an atrioventricular septal defect with a cleft mitral leaflet, gives left axis deviation (superior axis).

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 Cardiology: atrial septal defect?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.