The heart rate story

The role of heart rate is well established in the development and pathophysiology of myocardial ischaemia. In patients with coronary artery disease, most ischaemic episodes are triggered by an increase in heart rate, which induces an imbalance between myocardial oxygen delivery and consumption. Therefore, heart rate reduction has been considered as an important therapeutic approach in preventing ischaemia by reducing myocardial oxygen consumption and improving myocardial perfusion, by prolonging the diastolic interval. In addition to the beneficial effects of heart rate reduction for the prevention of ischaemia, a lower heart rate is associated with a more favourable prognosis. Recently, prospective investigation of the prognostic role of resting heart rate in patients with coronary artery disease and left ventricular systolic dysfunction, using the placebo arm of the BEAUTIFUL study, showed that elevated heart rate was associated with an increased risk of adverse fatal and non-fatal cardiac events. Ivabradine is a new medication which lowers heart rate by selectively inhibiting the If current, without other direct cardiovascular effects. Therefore, ivabradine opens up new opportunities in the management of patients with coronary artery disease.