Carotid Baroreceptor Stimulation, Sympathetic Activity, Baroreflex Function, and Blood Pressure in Hypertensive Patients

• Published in: Hypertension (Dallas, Tex. 1979) Tex. 1979), 2010-03, Vol.55 (3), p.619-626
• Main Authors: Heusser, Karsten, Tank, Jens, Engeli, Stefan, Diedrich, André, Menne, Jan, Eckert, Siegfried, Peters, Tim, Sweep, Fred C.G.J, Haller, Hermann, Pichlmaier, Andreas M, Luft, Friedrich C, Jordan, Jens
• Format: Article
• Language: English
• Subjects: Adult; Aged; Antihypertensive Agents - therapeutic use; Arterial hypertension. Arterial hypotension; Baroreflex - physiology; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure - physiology; Cardiology. Vascular system; Carotid Sinus - innervation; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Drug Resistance - physiology; Electric Stimulation Therapy - methods; Feasibility Studies; Female; Heart Rate - physiology; Humans; Hypertension - drug therapy; Hypertension - physiopathology; Hypertension - therapy; Male; Medical sciences; Middle Aged; Neural Inhibition - physiology; Pressoreceptors - physiology; Prospective Studies; Renin - blood; Stroke Volume - physiology; Sympathetic Nervous System - physiology
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/HYPERTENSIONAHA.109.140665

In animals, electric field stimulation of carotid baroreceptors elicits a depressor response through sympathetic inhibition. We tested the hypothesis that the stimulation acutely reduces sympathetic vasomotor tone and blood pressure in patients with drug treatment–resistant arterial hypertension. Furthermore, we tested whether the stimulation impairs the physiological baroreflex regulation. We studied 7 men and 5 women (ages 43 to 69 years) with treatment-resistant arterial hypertension. A bilateral electric baroreflex stimulator at the level of the carotid sinus (Rheos) was implanted ≥1 month before the study. We measured intra-arterial blood pressure, heart rate, muscle sympathetic nerve activity (microneurography), cardiac baroreflex sensitivity (cross-spectral analysis and sequence method), sympathetic baroreflex sensitivity (threshold technique), plasma renin, and norepinephrine concentrations. Measurements were performed under resting conditions, with and without electric baroreflex stimulation, for ≥6 minutes during the same experiment. Intra-arterial blood pressure was 193±9/94±5 mm Hg on medications. Acute electric baroreflex stimulation decreased systolic blood pressure by 32±10 mm Hg (range+7 to −108 mm Hg; P=0.01). The depressor response was correlated with a muscle sympathetic nerve activity reduction (r=0.42; P