Heart Rate As a Biomarker in Heart Failure: Role of Heart Rate Lowering Agents
Heart failure (HF) is a common clinical condition affecting more than 5.8 million people in the United States, it remains the leading cause of death in the United States and worldwide. Ongoing challenges for biomarker identification include the need for objective assessment, measurement precision, and meaningful replication. Biomarkers not only serve as traditional predictors of prognosis, they can also help to identify high-risk patients who need closer monitoring and more aggressive therapy; therefore, we reviewed the use of heart rate (HR) as a biomarker in HF both of diagnostic and prognostic values, in addition, to being easily detected. HR is a determinant of myocardial oxygen demand, coronary blood flow, and myocardial performance and is central to the adaptation of cardiac output to metabolic needs. Increased HR is known to predict adverse outcome in the general population and in patients with chronic HF. Part of the ability of HR to predict risk is related to the forces driving it, namely, neurohormonal activation. We reviewed therapies, which slow the HR like β-blockers and ivabradine (a drug that is a pure HR-reducing agent), and all the clinical studies suggest the benefit of these drugs in the management of HF, and increasing evidence suggests HR as a biomarker of both diagnostic and prognostic values in HF.