Short-Term Effects of Ivabradine in Patients with Chronic Stable Ischemic Heart Disease

INTRODUCTION: Ivabradine is a novel selective If current inhibitor with anti-ischemic and antianginal activity. OBJECTIVES: To assess the effect of the selective If current inhibitor ivabradine on heart rate, angina pectoris, and functional capacity in stable patients with chronic coronary artery disease on maximally tolerated medical therapy. MATERIALS AND METHODS: Consecutive patients from the out-patient cardiology clinic with stable coronary artery disease documented by coronary angiography were included. Patients had to be on maximally tolerated medical therapy with β-blockers, angiotensin-converting enzyme inhibitors or receptor blockers (ACE-I or ARB), antiplatelets, statins, nitrates, and anti-metabolics with a baseline heart rate of at least 70 beats per minute. All patients underwent assessment of angina (Canadian Cardiovascular Society Angina Class: CCS I to IV) and functional capacity (using a validated self-administered questionnaire), at baseline and after 4 months of ivabradine therapy. RESULTS: Twenty patients were enrolled (mean age 47 ± 7 years, all male, 60% with hypertension, 30% with diabetes mellitus). Patients were on optimal medical regimen of aspirin (100%), β-blocker (100%), statins (100%), clopidogrel (90%), nitrates (35%), anti-metabolics (90%), and ACE-I or ARB (95%). At baseline, the majority of patients (90%) were in CCS class II-IV. All patients were started on ivabradine 5 mg twice daily, and in 12 patients the dose was increased to 7.5 mg twice daily. After 4 months of treatment, the heart rate was significantly reduced from an average of 82 ± 8 to 68 ± 6 bpm (P < 0.001). The reduction in heart rate was accompanied by a significant improvement in functional capacity (score 3.5 ± 0.9 to 4.7 ± 0.7, P < 0.001) and angina classification; at baseline 10% of the patients were in CCS class I compared to 50% after 4 months of therapy (P = 0.01). No symptomatic bradycardia was reported with ivabradine. CONCLUSION: The addition of ivabradine to optimal medical therapy in patients with stable coronary artery disease is associated with significant improvement in anginal symptoms and functional capacity.