Cardiology: complications of myocardial infarction: 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: complications of myocardial infarction

Sample item

Four days after an inferior myocardial infarction, a 66-year-old man suddenly develops severe breathlessness and pulmonary oedema. A new loud apical pansystolic murmur is heard, but the first heart sound is soft and the ECG shows no new infarct. Which structure is most likely involved, and why is it vulnerable?

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

The answer and the reasoning

B. Posteromedial papillary muscle, which has a single blood supply

Papillary muscle rupture occurs 2 to 7 days after infarction and causes acute severe mitral regurgitation and flash pulmonary oedema, sometimes with only a soft murmur because equalisation of pressures occurs rapidly. The posteromedial papillary muscle is supplied only by the posterior descending artery, so it is more often infarcted than the anterolateral muscle, which has a dual supply. Urgent echocardiography and surgery are needed.

Option by option

  • A. Anterolateral papillary muscle, which has a dual blood supply

    The anterolateral papillary muscle is supplied by both LAD and circumflex branches, so it is relatively protected.

  • B. Posteromedial papillary muscle, which has a single blood supply (correct)

    Single-vessel supply makes the posteromedial muscle prone to necrosis and rupture in inferior infarction.

  • C. Chordae of the tricuspid valve, which are thin

    Tricuspid chordal rupture would not cause left-sided pulmonary oedema.

  • D. Interventricular septum, which has a single blood supply

    Septal rupture causes a VSD murmur at the left sternal edge, not an apical mitral regurgitation murmur.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is B, Posteromedial papillary muscle, which has a single blood supply. Papillary muscle rupture occurs 2 to 7 days after infarction and causes acute severe mitral regurgitation and flash pulmonary oedema, sometimes with only a soft murmur because equalisation of pressures occurs rapidly.

Why is "Anterolateral papillary muscle, which has a dual blood supply" not the answer?

The anterolateral papillary muscle is supplied by both LAD and circumflex branches, so it is relatively protected.

Why is "Chordae of the tricuspid valve, which are thin" not the answer?

Tricuspid chordal rupture would not cause left-sided pulmonary oedema.

Why is "Interventricular septum, which has a single blood supply" not the answer?

Septal rupture causes a VSD murmur at the left sternal edge, not an apical mitral regurgitation murmur.

What concept does this question test?

It tests Cardiology: complications of myocardial infarction in General Medicine. The posteromedial papillary muscle is supplied only by the posterior descending artery, so it is more often infarcted than the anterolateral muscle, which has a dual supply. Urgent echocardiography and surgery are needed.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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: complications of myocardial infarction?

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.