Ivabradine reduces heart rate by blocking funny current (If) channels in the sino-atrial node. Unlike β-blockers, it is preferred in which clinical scenario?
- A Heart failure with preserved ejection fraction (HFpEF) where β-blockers are contraindicated
- B Atrial fibrillation with rapid ventricular response where AV nodal slowing is needed
- C Heart failure with reduced ejection fraction (HFrEF) in patients already on maximally tolerated β-blocker who remain in sinus rhythm with HR ≥70 bpm ✓
- D Vasospastic (Prinzmetal's) angina where β-blockade may worsen coronary spasm
Correct answer: C. Heart failure with reduced ejection fraction (HFrEF) in patients already on maximally tolerated β-blocker who remain in sinus rhythm with HR ≥70 bpm
Explanation
Ivabradine's indication in heart failure (per ACC/AHA and ESC guidelines) is specifically HFrEF with LVEF ≤35%, sinus rhythm, resting HR ≥70 bpm despite maximum tolerated β-blocker dose (or when β-blocker is genuinely contraindicated). By inhibiting If channels in the SA node, it reduces HR without affecting myocardial contractility, conductivity through AV node, or β-adrenoceptors. It has no effect in AF (the If channel slows SA node automaticity, not AV conduction). The SHIFT trial demonstrated reduced hospitalisation and CV death.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.