Baroreflex: Physiology, Clinical Relevance and Diagnostic Procedures

The baroreflex is a key homeostatic mechanism of the cardiovascular system mediated by the autonomous nervous system. An increase of arterial blood pressure leads to a decrease of heart rate and arterial resistance and vice versa. This mechanism prevents excessive fluctuations and maintains a stable steady state of arterial blood pressure. The extent of baroreflex activity is a strong and independent risk predictor of mortality and adverse cardiac events. Diseases of the cardiovascular system are commonly linked to reduced baroreflex function. Good therapy response under these conditions correlates not only with an improved prognosis but also with a significant improvement of baroreflex function. Baroreflex sensitivity (BRS) is the quantitative description of the baroreflex gain in response to blood pressure changes. So far, several approaches have been proposed to assess baroreflex sensitivity. To render BRS assessment feasible in daily clinical routine, the following requirements will have to be addressed: optimization of the methods in terms of measurability and reliability; establishment of reference values; large prospective clinical validation trials.