Learning Objective
By the end of this section, learners should be able to explain the mechanism of action, clinical indications, and adverse effects of ivabradine in the management of chronic heart failure with reduced ejection fraction (HFrEF).
Mechanism of Action
Ivabradine is a selective pacemaker “funny” (If) sodium channel blocker.
- The If channel is responsible for the automaticity of the sinoatrial (SA) node
- These channels are upregulated in patients with chronic heart failure
Ivabradine works by:
- Decreasing the slope of diastolic depolarization in the SA node
Resulting in:
- ↓ Heart Rate
- No effect on myocardial contractility
- No effect on intracardiac conduction
This leads to improved diastolic filling time without negatively impacting cardiac output.
Clinical Indications
Ivabradine is used in chronic heart failure patients who continue to have symptoms despite receiving the maximum tolerable dose of β-blockers.
Eligibility Criteria
| Parameter | Requirement |
|---|---|
| Left Ventricular Ejection Fraction (LVEF) | ≤ 35% |
| Cardiac Rhythm | Sinus rhythm |
| Resting Heart Rate | ≥ 70 bpm |
Adverse Effects
| Common Side Effect | Clinical Manifestation |
|---|---|
| Bradycardia | Excessive slowing of the heart rate |
| Visual Disturbances | Blurred vision / luminous phenomena |
| Atrial Fibrillation | Increased incidence |
