Heart rate: an independent risk factor in cardiovascular disease

Large epidemiological studies have demonstrated that elevated heart rate is an independent risk factor for mortality and morbidity in healthy individuals with and without hypertension and in patients with coronary artery disease (CAD), myocardial infarction, and congestive heart failure. Elevated heart rate has been found to be a more powerful predictor of later death than depressed left ventricular function. This means that heart rate in patients with congestive heart failure is not only reflecting depressed cardiac function. Heart rate should be viewed in the same light as other risk factors, such as elevated blood pressure or cholesterol, smoking, cardiac dysfunction, or diabetes. It is well documented that interventions against these risk factors improve prognosis, in terms of both primary and secondary prevention. Several large placebo-controlled trials of patients with acute myocardial infarction or congestive heart failure have demonstrated that beta-blocking agents reduce mortality and morbidity. In fact, the effects seem to be more marked in patients with higher pre-treatment heart rates, and these patients also demonstrate a more marked reduction in heart rate. It seems reasonable to believe that heart rate reduction per se is of major importance for the effects of beta-blockers. Beneficial effects on the prognosis after myocardial infarction have also been shown for some calcium antagonists, which also reduce heart rate. Heart rate should be considered as an important risk factor in patients at risk of CAD or with established CAD. Treatment should be started to reduce heart rate to a normal level, similar to the aim in the treatment of patients with hypertension.