Carotid chemoreflex and muscle metaboreflex interact to the regulation of ventilation in patients with heart failure with reduced ejection fraction.

Autor: Machado AC; Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, RJ, Brazil.; Latin American Institute of Life and Nature Sciences, Federal University of Latin American Integration, Foz do Iguaçu, PR, Brazil., Vianna LC; Faculty of Physical Education, University of Brasília, Brasilia, DF, Brazil., Gomes EAC; Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, RJ, Brazil., Teixeira JAC; Antonio Pedro University Hospital, Faculty of Medicine, Fluminense Federal University, Niterói, RJ, Brazil., Ribeiro ML; Antonio Pedro University Hospital, Faculty of Medicine, Fluminense Federal University, Niterói, RJ, Brazil., Villacorta H; Antonio Pedro University Hospital, Faculty of Medicine, Fluminense Federal University, Niterói, RJ, Brazil., Nobrega ACL; Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, RJ, Brazil., Silva BM; Department of Physiology, Federal University of São Paulo, São Paulo, SP, Brazil.
Jazyk: angličtina
Zdroj: Physiological reports [Physiol Rep] 2020 Feb; Vol. 8 (3), pp. e14361.
DOI: 10.14814/phy2.14361
Abstrakt: Synergism among reflexes probably contributes to exercise hyperventilation in patients with heart failure with reduced ejection fraction (HFrEF). Thus, we investigated whether the carotid chemoreflex and the muscle metaboreflex interact to the regulation of ventilation ( V ˙ E ) in HFrEF. Ten patients accomplished 4-min cycling at 60% peak workload and then recovered for 2 min under either: (a) 21% O 2 inhalation (tonic carotid chemoreflex activity) with legs' circulation free (inactive muscle metaboreflex); (b) 100% O 2 inhalation (suppressed carotid chemoreflex activity) with legs' circulation occluded (muscle metaboreflex activation); (c) 21% O 2 inhalation (tonic carotid chemoreflex activity) with legs' circulation occluded (muscle metaboreflex activation); or (d) 100% O 2 inhalation (suppressed carotid chemoreflex activity) with legs' circulation free (inactive muscle metaboreflex) as control. V ˙ E , tidal volume (V T ) and respiratory frequency (f R ) were similar between each separated reflex (protocols a and b) and control (protocol d). Calculated sum of separated reflexes effects was similar to control. Oppositely, V ˙ E (mean ± SEM: Δ vs. control = 2.46 ± 1.07 L/min, p = .05) and f R (Δ = 2.47 ± 0.77 cycles/min, p = .02) increased versus control when both reflexes were simultaneously active (protocol c). Therefore, the carotid chemoreflex and the muscle metaboreflex interacted to V ˙ E regulation in a f R -dependent manner in patients with HFrEF. If this interaction operates during exercise, it can have some contribution to the HFrEF exercise hyperventilation.
(© 2020 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)
Databáze: MEDLINE
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