Cardiology: ivabradine mechanism: 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: ivabradine mechanism

Sample item

A 55-year-old man with heart failure and an ejection fraction of 30% is in sinus rhythm with a resting heart rate of 84 per minute despite the maximum tolerated beta-blocker dose. Ivabradine is added. What is its mechanism of action?

ABlockade of L-type calcium channels in the AV nodeBInhibition of the funny current in the sinus nodeCStimulation of muscarinic receptors in the atriaDBlockade of beta-1 receptors in the sinus node

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

The answer and the reasoning

B. Inhibition of the funny current in the sinus node

Ivabradine blocks the If pacemaker current in sinoatrial node cells and slows the heart rate without lowering contractility or blood pressure. It reduces hospital admission in heart failure with sinus rhythm and a rate of 70 per minute or more on optimal therapy.

Option by option

A. Blockade of L-type calcium channels in the AV node
L-type calcium channel blockade is the action of verapamil and diltiazem.
B. Inhibition of the funny current in the sinus node (correct)
Correct. Blocking the funny current slows diastolic depolarisation in the sinus node.
C. Stimulation of muscarinic receptors in the atria
Muscarinic stimulation is the action of vagal agents, not ivabradine.
D. Blockade of beta-1 receptors in the sinus node
Beta-1 blockade is the action of beta-blockers, which he already takes.

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 B, Inhibition of the funny current in the sinus node. Ivabradine blocks the If pacemaker current in sinoatrial node cells and slows the heart rate without lowering contractility or blood pressure.

Why is "Blockade of L-type calcium channels in the AV node" not the answer?

L-type calcium channel blockade is the action of verapamil and diltiazem.

Why is "Stimulation of muscarinic receptors in the atria" not the answer?

Muscarinic stimulation is the action of vagal agents, not ivabradine.

Why is "Blockade of beta-1 receptors in the sinus node" not the answer?

Beta-1 blockade is the action of beta-blockers, which he already takes.

What concept does this question test?

It tests Cardiology: ivabradine mechanism in General Medicine. It reduces hospital admission in heart failure with sinus rhythm and a rate of 70 per minute or more on optimal therapy.

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: ivabradine mechanism?

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.