Daniel Pella
The major determinants of myocardial oxygen consumption include preload, afterload, myocardial contractility, and heart rate. Presumably heart rate is the most important determinant and its reduction would be predicted to be beneficial in the management of many forms of ischaemic heart disease, including chronic stable angina, acute coronary syndromes, and heart failure. Lowering heart rate not only reduces myocardial oxygen demands but can also improve blood flow, especially in the endocardium, by increasing diastolic coronary perfusion time. More generally, a sustained elevation of heart rate has been proposed to be an independent predictor of mortality, not only in patients with coronary artery disease but in the general population as well. Furthermore, the reduction of mortality in patients with coronary artery disease or heart failure observed with therapy using beta-adrenergic blockers, or some calcium channel blockers has been attributed, in large part, to the heart rate-lowering actions of these agents. Thus, decrease of heart rate should be considered to be a new therapeutic target in these special groups of patients.