Elevated heart rate: a major risk factor for cardiovascular disease.

Mounting evidence shows that elevated heart rate is associated with a greater risk of developing hypertension and atherosclerosis and that it is a potent predictor of cardiovascular morbidity and mortality. These relationships have been shown not only in general populations but also among hypertensive individuals, with important implications for the treatment of hypertension. In spite of this evidence heart rate has been overlooked as a risk factor, but the fact that in most studies the risk related to fast heart rate remained highly significant after controlling for major risk factors for atherosclerosis suggests that it plays a direct role in the induction of the risk. The clustering of several risk factors for coronary artery disease in subjects with fast heart rate suggests that sympathetic overactivity accounts for the increased cardiovascular morbidity in subjects with tachycardia. In fact, experimental studies have shown that a heightened sympathetic tone can cause obesity, hyperinsulinemia, and insulin resistance which in the long run can promote the development of atherosclerosis. Moreover, experimental studies in the animal suggest that the heamodynamic disturbances related to high heart rate have a direct impact on the arterial wall promoting the development of atherosclerotic plaques. Preliminary results in the experimental animal and pooled data from intervention studies in patients with myocardial infarction or congestive heart failure suggest that drug-induced reduction of heart rate may be beneficial in several clinical conditions.