Selective Inhibition of Cardiac Pacemaker (I f ) Current: the Role of Ivabradine in the Treatment of Angina

Heart rate reduction plays a pivotal role in the management of myocardial ischemia and chronic stable angina. Rate-slowing drugs, such as beta-blockers are considered the cornerstone of antianginal therapy. However, the broad use of beta-blockers is limited by their side-effects. Ivabradine is the representative of a new class of agents that exclusively reduce heart rate through inhibition of the sinoatrial pacemaker (I f ) current. Ivabradine reduces cardiac heart rate in doses that do not affect other ionic currents, resulting in a decrease in cardiac oxygen consumption and in an increase in diastolic period. Ivabradine has no negative inotropic or lusitropic effects, and does not change any major electrophysiological parameter. Large randomized trials have provided evidence for its efficacy in stable angina and have demonstrated anti-ischemic properties similar to atenolol and amlodipine. Moreover, ivabradine provides an attractive alternative to conventional therapy, whenever use of beta-blockers or calcium-channel blockers is contraindicated. Treatment of sinus tachyarrhythmias is another area where the use of ivabradine seems promising. Ongoing trials with ivabradine will determine its effect on mortality and morbidity in patients with coronary artery disease and left ventricular dysfunction.