Patients with chronic stable angina pectoris were randomized to treatment with ivabradine (5 to 7.5 mg bid) or placebo for 4 months, in addition to atenolol 50 mg od. The effect of treatment on exercise tolerance test parameters was analyzed in two groups according to baseline HR: > 65 bpm (n = 418) versus ¡Ü 65 bpm (n = 436) (above and below the median, respectively).
Ivabradine reduced resting HR in both groups with placebo-corrected reductions of ? 9.1 (95 % CI ? 11.0 to ? 7.3; > 65 bpm group) and ? 5.9 (95 % CI ? 7.5 to ? 4.3; ¡Ü 65 bpm group) (both P < 0.001 versus placebo). Ivabradine reduced heart rate at all stages of exercise (all P < 0.001). Improvements in exercise capacity (total exercise duration, time to limiting angina, angina onset, and 1-mm ST segment depression, all P < 0.05) were recorded in both HR groups. There were no differences between the two groups in terms of safety.
Ivabradine resulted in significant improvements in exercise capacity relative to placebo in patients with stable angina pectoris receiving beta-blocker therapy whether their resting HR was above or below 65 bpm.