Cardiology: atrioventricular block: 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: atrioventricular block

Sample item

A 72-year-old man has had two syncopal episodes. His ECG shows a constant PR interval of 180 ms in conducted beats, with intermittent single non-conducted P waves and a QRS duration of 140 ms. Which is the most appropriate definitive treatment?

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

The answer and the reasoning

C. Permanent pacemaker implantation

A constant PR interval with sudden dropped beats is Mobitz type II block, usually infranodal (His-Purkinje) and associated with a wide QRS. It can progress abruptly to complete heart block and asystole, so a permanent pacemaker is indicated, especially with syncope. Mobitz I (Wenckebach) has progressive PR lengthening, is usually nodal and is often benign.

Option by option

  • A. Observation, because this pattern is benign

    Observation suits asymptomatic Wenckebach block, not infranodal Mobitz II with syncope.

  • B. Radiofrequency ablation of the AV node

    AV node ablation would create complete block and is used for rate control in refractory atrial fibrillation, not to treat block.

  • C. Permanent pacemaker implantation (correct)

    Mobitz II with symptoms is a class I indication for permanent pacing.

  • D. Long-term oral atropine

    Oral atropine is not a reliable long-term treatment and is ineffective for infranodal block.

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 C, Permanent pacemaker implantation. A constant PR interval with sudden dropped beats is Mobitz type II block, usually infranodal (His-Purkinje) and associated with a wide QRS.

Why is "Observation, because this pattern is benign" not the answer?

Observation suits asymptomatic Wenckebach block, not infranodal Mobitz II with syncope.

Why is "Radiofrequency ablation of the AV node" not the answer?

AV node ablation would create complete block and is used for rate control in refractory atrial fibrillation, not to treat block.

Why is "Long-term oral atropine" not the answer?

Oral atropine is not a reliable long-term treatment and is ineffective for infranodal block.

What concept does this question test?

It tests Cardiology: atrioventricular block in General Medicine. It can progress abruptly to complete heart block and asystole, so a permanent pacemaker is indicated, especially with syncope. Mobitz I (Wenckebach) has progressive PR lengthening, is usually nodal and is often benign.

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: atrioventricular block?

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.