The role of heart rate in coronary artery disease and heart failure has been explored using ivabradine, a drug that selectively targets heart rateIncreased heart rate can provoke myocardial ischaemiaHeart rate reduction can reduce the symptoms of anginaIncreased heart rate is a risk marker in patients with coronary artery disease, but heart rate reduction does not improve prognosis in this clinical settingIn the setting of heart failure, elevated heart rate is a modifiable risk factor — reducing heart rate improves prognosis in these patientsExcessive bradycardia can cause dispersion of atrial fibrillation