Ivabradine is a speci c inhibitor of the If current involved in sinoatrial nodal activity and reduces the heart rate of patients in normal sinus rhythm without lowering blood pressure. In the SHIFT (Systolic HF Treatment with the If Inhibitor Ivabradine) trial of 6,505 subjects with stable, chronic, predominantly NYHA class II and III HFrEF, ivabradine therapy, when added to GDMT, resul- ted in a signi cant reduction in HF hospitalizations (28). Bene ts were noted especially for those patients with contraindications to beta-blockers, on beta-blocker doses #50% of GDMT targets (29), and with resting heart rate $77 beats/min at study entry (30). It is important to emphasize that ivabradine is indicated only for patients mainly in sinus rhythm, not in those with persistent or chronic AF, those experiencing 100% atrial pacing, or unstable patients. A history of paroxysmal AF is not a contraindication to ivabradine; in the SHIFT study, nearly 10% of patients had a history of paroxysmal AF. In this study, there was a requirement for sinus rhythm at least 40% of the time. From a safety standpoint, patients treated with ivabradine had greater rates of bradycardia and transient blurring of vision (28). In the 2016 ACC/AHA/HFSA HF guideline update (6), ivabradine was recommended as a Class IIa, Level of Ev- idence: B-R (3,4) therapy to reduce the risk of HF hospi- talization in patients with HFrEF (LVEF #35%) already receiving GDMT (including a beta-blocker at the maxi- mally tolerated dose), and who are in sinus rhythm with a heart rate greater than 70 beats/min at rest (Figures 2 and 3, Tables 1, 2, and 5). The contraindications to ivabradine are enumerated in Table 4. 