The Efficacy of Electrical Baroreflex Activation Therapy is Independent of Peripheral Chemoreceptor Modulation

Introduction Baroreflex activation through electrical carotid sinus stimulation has been developed for the treatment of patients with arterial hypertension not sufficiently responding to pharmacological therapy. Previous studies suggested that peripheral chemoreflex afferents located in proximity to carotid baroreceptors are tonically active in hypertensive patients and may inhibit baroreflex responses. Therefore, we hypothesized that peripheral chemoreflex activation attenuates the efficacy of electrical carotid sinus stimulation. Methods We screened 35 patients with an implanted electrical carotid sinus stimulator. Of those, 11 patients exhibited a consistent acute depressor response and were included in the study (7 men/4 women, age: 67±8 years, BMI: 31.6±5.2 kg/m2, 6±2 antihypertensive drug classes). We assessed responses to electrical baroreflex stimulation during normoxia, isocapnic hypoxia (SpO2: 79.0±1.5%), and hyperoxia (40% end-tidal O2 fraction) by recording ECG, blood pressure (SBP), ventilati...