Congestive Heart Failure (CHF) Practice Test

Ivabradine lowers the heart rate by selectively blocking the If current in the sinoatrial node, reducing resting heart rate and thus myocardial oxygen demand. In heart failure with reduced ejection fraction, it is used to cut HF hospitalizations in patients who remain symptomatic despite guideline-directed therapy and who meet a specific heart-rate criterion. The key requirement is being in sinus rhythm with a resting heart rate of 70 beats per minute or higher while on maximally tolerated beta-blocker therapy. This is the population shown to benefit in trials like SHIFT.

It isn’t appropriate in atrial fibrillation because ivabradine relies on a functioning sinoatrial node in sinus rhythm to slow the rate; with AF, there isn’t a stable sinus rhythm to target. It isn’t indicated when the resting heart rate is already below 60 bpm, since further slowing could cause bradycardia and lack of benefit. It also isn’t a treatment for ventricular tachycardia, which requires other antiarrhythmic approaches.