Search

BACKGROUND: Clinic resting heart rate (RHR), is one of the cardiovascular parameters more easily measurable. In the general population RHR has been associated with total and cardiovascular mortality and higher rate of vascular events. OBJECTIVE: The case of essential hypertension is in some ways peculiar: in the past decades has often been attributed to hypertensive subjects higher values of RHR than healthy controls as a result of the effects of the different factors leading to the development of essential hypertension itself, first of all the presence of an increased tone of the sympathetic nervous system Methods: Several excellent articles debated the issue of autonomic dysfunction in essential hypertension; nevertheless of this, after various decades of debate, this issue is to-date unresolved. The aim of this review is to discuss the reliability of the hypothesis that elevated resting heart rate in hypertensive subjects is associated to high blood pressure and both to elevated sympathetic nervous system activity or rather if these three phenomena coexist in a limited portion of subjects being not necessarily linked each other with a causal relationship. RESULTS: The ascertainment of the exact proportion of the hypertensive subjects having sympathetic overdrive appears to be hard, not only due to the multiple interferences and the constant interplay between the various determinants of the sympathetic tone, but also because a significant uncertainty remains with regard to the validity of the methods used for assessing the sympathetic tone. CONCLUSIONS: To date, any threshold used to define tachycardia is arbitrary. The percentage of hypertensive patients with elevated RHR varies considerably between the various studies, first of all because the modality of assessment influences the results. The "white coat tachycardia" is a clinical entity that must be taken into account. Ambulatory heart rate represents a good diagnostic alternative, since nocturnal mean heart rate appears to be the parameter with the highest prognostic value, probably because is less conditioned by external factors, being more representative of the "real" heart rate of the subject.