Ivabradine decreases heart rate without affecting the heart's contractility.  It works by decreasing sodium flow across funny channels, which decreases SA node firing and subsequently slows the heart rate. Since it does not affect inotropy, it can be used to treat angina and systolic heart failure in patients who can’t be on a beta-blocker.  Adverse effects include a luminous phenomenon, which is caused by inhibition of ion channels in the retina that resemble funny channels.

Key Points

  • Ivabradine
    • Mechanism
      • Selective inhibition of funny channels
        • Prolongs the slow depolarization phase (phase 4) of the pacemaker potential
      • Decreases SA node firing
        • Negative chronotropic effect without inotropy
        • Reduces cardiac O2 requirement
    • Clinical Use
      • Chronic stable angina in patients who cannot take B-blockers
      • Chronic heart failure with reduced ejection fraction
    • Adverse Effects
      • Luminous phenomenon / visual brightness
        • Caused by inhibition of ion channels in the retina that are similar to funny channels
      • Bradycardia