Ivabradine reduces heart rate in heart failure patients with sinus rhythm by selectively blocking:

• A Funny current (If) HCN channels in SA node pacemaker cells ✓
• B β1-adrenoceptors in the SA node
• C L-type calcium channels in SA node
• D Muscarinic M2 receptors in the AV node

Explanation

Ivabradine specifically blocks the hyperpolarisation-activated cyclic nucleotide-gated (HCN) channels responsible for the funny current (If) in SA node pacemaker cells, which slows spontaneous depolarisation and reduces heart rate without affecting myocardial contractility or blood pressure. It is used in HFrEF patients in sinus rhythm with resting HR ≥70 bpm despite maximally tolerated beta-blocker therapy.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.