BACKGROUND: Chemoreflex-mediated sympathetic activation contributes to both initiation and progression of chronic heart failure (CHF). METHOD: To study the direct role of increased peripheral chemosensitivity in reducing sympathetic baroreflex function in CHF patients, we compared sympathetic baroreflex function, assessed by the slope of the relationship between muscle sympathetic nerve activity (MSNA) and DBP, in CHF patients with augmented (n = 18) and normal (n = 20) peripheral chemosensitivity. Using a double-blind, randomized, vehicle-controlled study, we examined the effect of chemoreflex deactivation (by breathing 100% oxygen for 15 min) on sympathetic baroreflex function in CHF patients with elevated and with normal chemosensitivity. RESULTS:Baseline MSNA was elevated (60.6 ± 3.2 vs. 48.9 ± 3.7 bursts/min, P < 0.05) and sympathetic baroreflex function impaired (3.06 ± 0.55 vs. 5.51 ± 0.69 % bursts/mmHg, P < 0.05) in CHF patients with augmented peripheral chemosensitivity compared with controls. Administration of 100% oxygen led to a significant decrease in MSNA (from 60.5 ± 3.2 to 52.6 ± 3.2 bursts/min, P < 0.001) and increase in sympathetic baroreflex (from 2.95 ± 0.56 to 6.18 ± 0.77, P < 0.001) in CHF patients with enhanced chemoreflex sensitivity. In contrast, neither room air nor 100% oxygen changed MSNA, hemodynamics or sympathetic baroreflex function in CHF patients with normal chemosensitivity. CONCLUSION: We report for the first time that increased peripheral chemoreflex sensitivity directly decreases sympathetic baroreflex function in CHF patients. This interaction contributes to sympathetic overactivity and blunted sympathetic baroreflex function of CHF patients and may explain how chemoreceptors contribute to the bad prognosis of CHF patients.
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BACKGROUND: Chemoreflex-mediated sympathetic activation contributes to both initiation and progression of chronic heart failure (CHF). METHOD: To study the direct role of increased peripheral chemosensitivity in reducing sympathetic baroreflex function in CHFpatients, we compared sympathetic baroreflex function, assessed by the slope of the relationship between muscle sympathetic nerve activity (MSNA) and DBP, in CHFpatients with augmented (n = 18) and normal (n = 20) peripheral chemosensitivity. Using a double-blind, randomized, vehicle-controlled study, we examined the effect of chemoreflex deactivation (by breathing 100% oxygen for 15 min) on sympathetic baroreflex function in CHFpatients with elevated and with normal chemosensitivity. RESULTS: Baseline MSNA was elevated (60.6 ± 3.2 vs. 48.9 ± 3.7 bursts/min, P < 0.05) and sympathetic baroreflex function impaired (3.06 ± 0.55 vs. 5.51 ± 0.69 % bursts/mmHg, P < 0.05) in CHFpatients with augmented peripheral chemosensitivity compared with controls. Administration of 100% oxygen led to a significant decrease in MSNA (from 60.5 ± 3.2 to 52.6 ± 3.2 bursts/min, P < 0.001) and increase in sympathetic baroreflex (from 2.95 ± 0.56 to 6.18 ± 0.77, P < 0.001) in CHFpatients with enhanced chemoreflex sensitivity. In contrast, neither room air nor 100% oxygen changed MSNA, hemodynamics or sympathetic baroreflex function in CHFpatients with normal chemosensitivity. CONCLUSION: We report for the first time that increased peripheral chemoreflex sensitivity directly decreases sympathetic baroreflex function in CHFpatients. This interaction contributes to sympathetic overactivity and blunted sympathetic baroreflex function of CHFpatients and may explain how chemoreceptors contribute to the bad prognosis of CHFpatients.
Authors: Catherine F Notarius; Philip J Millar; Hisayoshi Murai; Beverley L Morris; Susan Marzolini; Paul Oh; John S Floras Journal: J Physiol Date: 2014-12-15 Impact factor: 5.182
Authors: Jacqueline K Limberg; Jennifer L Taylor; Michael T Mozer; Simmi Dube; Ananda Basu; Rita Basu; Robert A Rizza; Timothy B Curry; Michael J Joyner; Erica A Wehrwein Journal: Hypertension Date: 2015-04-13 Impact factor: 10.190