Epidemiological studies have shown that a high heart rate at rest is a risk factor for global and cardiovascular mortality.1-3 A rapid heart rate is associated with a variety of prognostic factors indicative of worse heart conditions (for example, hypoxaemia, anaemia, alcohol consumption, low physical training status). The link between a high resting heart rate and an increase in overall and cardiovascular mortality has, however, been shown to be independent of cardiac conditions that can contribute to an increase in the resting heart rate, and persists after adjustment for other classic variables (sex, arterial pressure, and alcohol consumption).2 ,3

Recently, an elegant study showed that, among mammals, the relation between the number of beats per lifetime and life expectancy was remarkably constant, and the provocative question was raised as whether human life could be extended by slowing the heart rate.4Of course, such a study using bradycardiac drugs has not yet been performed, but these data point to the potential beneficial effect of heart rate lowering drugs in patients with cardiac disorders. This review examines the impact on the cardiovascular system of treatments which lower the heart rate.