Rationale and Design of the Effect of Ivabradine on Exercise Tolerance in Patients With Chronic Heart Failure (EXCILE-HF) Trial - Protocol for a Multicenter Randomized Controlled Trial.

Background: A high resting heart rate is an independent risk factor for mortality and morbidity in patients with cardiovascular diseases. Ivabradine selectively inhibits the funny current (I _f) and decreases heart rate without affecting cardiac conduction, contractility, or blood pressure. The effect of ivabradine on exercise tolerance in patients with heart failure with reduced ejection fraction (HFrEF) on standard drug therapies remains unclear. Methods and Results: This multicenter interventional trial of patients with HFrEF and a resting heart rate ≥75 beats/min in sinus rhythm treated with standard drug therapies will consist of 2 periods: a 12-week open-label, randomized, parallel-group intervention period (standard drug treatment+ivabradine group and standard drug treatment group) to compare changes in exercise tolerance between the 2 groups; and a 12-week open-label ivabradine treatment period for all patients to evaluate the effect of adding ivabradine on exercise tolerance. The primary endpoint will be the change in peak oxygen uptake (V̇O₂) during the cardiopulmonary exercise test from Week 0 (baseline) to Week 12. Secondary endpoints will be time-dependent changes in peak V̇O₂ from Week 0 to Weeks 12 and 24. Adverse events will also be evaluated. Conclusions: The EXCILE-HF trial will provide meaningful information regarding the effects of ivabradine on exercise tolerance in patients with HFrEF receiving standard drug therapies and suggestions for the initiation of ivabradine treatment.