Almost all the epidemiological studies that aimed to answer the question of the relationship between heart rate and all-cause or cardiovascular morbidity and mortality reported that a high heart rate was associated with a higher risk of all-cause mortality and cardiovascular events. This relationship has been found to be generally stronger in men than among women. The increase in the cardiovascular risk, associated with the acceleration of heart rate, was comparable to the increase in risk observed with high blood pressure. It has been shown that an increase in heart rate by 10 beats per minute was associated with an increase in the risk of cardiac death by at least 20%, and this increase in the risk is similar to the one observed with an increase in systolic blood pressure by 10 mm Hg. It has also been shown that heart rate recorded in elderly men has a strong predictive value in survival to a very old age. Taken together, these results indicate that the risk associated with accelerated heart rate is not only statistical significant but also clinically relevant and that it should be taken into account in the evaluation of the patients. Although the association between elevated heart rate and cardiovascular morbidity and mortality has been demonstrated in a large number of epidemiological studies, tachycardia has remained a neglected cardiovascular risk factor until very recently. For the first time, the recent guidelines of the European Society of Cardiology and the European Society of Hypertension indicate than an accelerated heart rate is considered as an independent risk factor and potentially as a target for pharmacologic therapies, especially in high-risk patients.