Curr Hypertens Rep (2010) 12:61–66 carotid arteries. A programmer system can interact with the pulse generator, making it possible to noninvasively control the delivery of the activation energy. The device has independent output circuits for the left and right leads, and four independent therapies can be programmed, to optimize the performance. Each therapy has independent control of start and stop times, ramp function, dose settings, burst settings, pulse amplitude, pulse width, pulse frequency, and therapy pathway. In 2003, 11 normotensive patients undergoing carotid endarterectomy were enrolled in the Baroreflex Activation System Study (BRASS) [51 ]. The carotid sinus barore- ceptors were briefly stimulated under local or general anesthesia through 1-minute incremental intervals. This study demonstrated an average decrease in systolic blood pressure from 144 mm Hg to 131 mm Hg, directly related to the intensity of stimulation. Chronic experimental application in humans is the next step. A case report recently described a patient with malignant hypertension who was successfully treated with the chronic implantable Rheos System [52 ]. Now, results from a multicenter feasibility study are available; participants with treatment-resistant hypertension underwent implan- tation of the Rheos System. This study shows an acceptable safety profile and a clinically and statistically significant reduction in office blood pressure of over 20 mm Hg systolic after 3 months of stimulation in 37 participants. A cohort of 17 participants was observed for up to 2 years and it was found that the blood pressure reduction could be sustained. Future Perspectives This new device may stimulate further research into the applicability of electrical activation of the carotid baroreflex, not only for treatment-resistant hypertension but also for related cardiovascular disorders. Studies are now being undertaken to evaluate baropacing in patients with conges- tive heart failure. Angina pectoris may be another area where the device could be useful. Of course, many problems still must be addressed. Apart from technical issues, these relate to the optimal use of the system. For instance, we do not know which settings will give the best results. Currently, frequency and voltage are set empirically, but there may be more dynamic ways to stimulate the baroreceptor system. We need to find out how we can best modify the settings in relation to the circadian pattern of blood pressure and heart rate. Also, it is unknown whether both carotids must be paced or whether unilateral stimulation will be effective. Beyond determining the preferred settings, another challenge is creating a closed- loop feedback system. 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