Abstract-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 Ն1 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 Ն6 minutes during the same experiment. Intra-arterial blood pressure was 193Ϯ9/94Ϯ5 mm Hg on medications. Acute electric baroreflex stimulation decreased systolic blood pressure by 32Ϯ10 mm Hg (range: ϩ7 to Ϫ108 mm Hg; Pϭ0.01). The depressor response was correlated with a muscle sympathetic nerve activity reduction (r 2 ϭ0.42; PϽ0.05). In responders, muscle sympathetic nerve activity decreased sharply when electric stimulation started. Then, muscle sympathetic nerve activity increased but remained below the baseline level throughout the stimulation period. Heart rate decreased 4.5Ϯ1.5 bpm with stimulation (PϽ0.05). Plasma renin concentration decreased 20Ϯ8% (PϽ0.05). Electric field stimulation of carotid sinus baroreflex afferents acutely decreased arterial blood pressure in hypertensive patients, without negative effects on physiological baroreflex regulation. The depressor response was mediated through sympathetic inhibition. (Hypertension. 2010;55:619-626.)

The results constitute the first observation of phenomena indicating electrical and mechanical coupling between allogeneic donor cardiomyocytes and recipient myocardium in-vivo. Further experiments are necessary to evaluate the technique as a potential therapy for atrioventricular block.

EF<40%, permanent atrial fibrillation, and QRS>or=150 ms are independent predictors for VT/VF occurrence in predominantly secondary prophylactic ICD patients. Combining all independent predictors, we developed a risk score for VT/VF occurrence identifying a subgroup of patients with two or more risk factors who had a 100% 2-year risk. Future studies will reveal if this risk score helps to identify ICD patients suitable for empirical anti-arrhythmic therapy and to improve patient selection for prophylactic ICD therapy.

Cumulative RV pacing > 2% and EF < 40% are independent predictors for VT/VF occurrence and mortality and hospitalization for heart failure in predominantly secondary prophylactic ICD patients. Our data show that algorithms capable of reducing cumulative RV pacing should be used more frequently in clinical practice.

small diameter vascular grafts can be engineered from an acellular allogeneic matrix seeded with autologous cells. Patency is superior to polydioxanone prostheses but inferior to the arterial autograft.