Cardioprotective medications referred to as the fantastic four are used to treat heart failure (HF). Additionally, ivabradine can also be used if the heart rate (HR) is elevated. An elevated HR is a prognostic factor in HF patients, as well as in the general population. In both HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF), an elevated HR is associated with all-cause mortality, whereas cardiovascular death is only associated with the former. In addition, previous clinical trials revealed that ivabradine was useful only in HFrEF but not in HFpEF. Therefore, ivabradine is indicated for patients only with HFrEF. Moreover, ivabradine increases the stroke volume by ensuring an effective diastolic time as a result of the decreased HR. Including this effect, the introduction of ivabradine allowed for the discontinuation of dobutamine infusion used in HF patients and the uptitration of β-blockers in other reports. Additionally, ivabradine improves exercise tolerance and the subjective symptoms of HF. However, the effects of ivabradine on exercise tolerance remain poorly understood, and prospective clinical trials are underway. While these beneficial effects have been reported, side effects such as photopsia and atrial fibrillation have also been reported. It is important to use ivabradine appropriately in conjunction with standard HF treatment, including quadruple therapy.