Heart rate as a treatable cardiovascular risk factor

Although several epidemiological studies demonstrate the association between resting heart rate (HR) and cardiovascular morbidity and mortality, an elevated HR remains a neglected cardiovascular risk factor. This review summarizes the results of published studies on the relationship between elevated HR and cardiovascular risk. The role of HR in myocardial ischaemia in coronary patients is well known. Experimental data and clinical observations support the importance of HR in the pathophysiology of atherosclerosis and plaque rupture. A large body of evidence points to high resting HR as a risk factor for mortality in various populations, including coronary patients. HR reduction is suggested to be a mechanism explaining the prognostic benefit of beta-blockers after myocardial infarction or in heart failure patients. However, it was unclear whether HR reduction per se directly affects cardiovascular prognosis. Treatment with ivabradine, a pure HR-reducing agent, provides an opportunity to assess the effects of selectively lowering HR without altering other aspects of cardiac function. The results of the recent Morbidity-Mortality Evaluation of the I-f Inhibitor Ivabradine in Patients with Coronary Disease and Left Ventricular Dysfunction study underline the importance of HR reduction in the management of stable coronary artery disease. The prospective analysis of data from the placebo arm demonstrated that elevated resting HR (>= 70 bpm) is a strong independent predictor of clinical outcomes. Consistent with these data, ivabradine significantly improved coronary outcomes in patients with a HR of 70 bpm or more. These data support the importance of HR in the management of stable coronary artery disease to assess prognosis and to guide optimal therapy.