In heart failure (HF), there is a reduced baroreflex sensitivity at rest, and during dynamic exercise there is enhanced muscle metaboreflex activation (MRA). However, how the arterial baroreflex modulates HR during exercise is unknown. We tested the hypothesis that spontaneous baroreflex sensitivity (SBRS) is attenuated during exercise in HF and that MRA further depresses SBRS. In seven conscious dogs we measured heart rate (HR), cardiac output, and left ventricular systolic pressure at rest and during mild and moderate dynamic exercise, before and during MRA (via imposed reductions of hindlimb blood flow), and before and after induction of HF (by rapid ventricular pacing). SBRS was assessed by the sequences method. In control, SBRS was reduced from rest with a progressive resetting of the baroreflex stimulus-response relationship in proportion to exercise intensity and magnitude of MRA. In HF, SBRS was significantly depressed in all settings; however, the changes with exercise and MRA occurred with a pattern similar to the control state. As in control, the baroreflex stimulus-response relationship showed an intensity- and muscle metaboreflex (MMR)-dependent rightward and upward shift. The results of this study indicate that HF induces an impairment in baroreflex control of HR at rest and during exercise, although the effects of exercise and MRA on SBRS occur with a similar pattern as in control, indicating the persistence of some vagal activity.

Iellamo, F., Sala Mercado, J.a., Ichinose, M., Hammond, R.l., Pallante, M., Ichinose, T., et al. (2007). Spontaneous baroreflex control of heart rate during exercise and muscle metaboreflex activation in heart failure. AMERICAN JOURNAL OF PHYSIOLOGY. HEART AND CIRCULATORY PHYSIOLOGY, 293(3), H1929-H1936 [10.1152/ajpheart.00564.2007].

Spontaneous baroreflex control of heart rate during exercise and muscle metaboreflex activation in heart failure

IELLAMO, FERDINANDO;PALLANTE, MARCO;
2007-01-01

Abstract

In heart failure (HF), there is a reduced baroreflex sensitivity at rest, and during dynamic exercise there is enhanced muscle metaboreflex activation (MRA). However, how the arterial baroreflex modulates HR during exercise is unknown. We tested the hypothesis that spontaneous baroreflex sensitivity (SBRS) is attenuated during exercise in HF and that MRA further depresses SBRS. In seven conscious dogs we measured heart rate (HR), cardiac output, and left ventricular systolic pressure at rest and during mild and moderate dynamic exercise, before and during MRA (via imposed reductions of hindlimb blood flow), and before and after induction of HF (by rapid ventricular pacing). SBRS was assessed by the sequences method. In control, SBRS was reduced from rest with a progressive resetting of the baroreflex stimulus-response relationship in proportion to exercise intensity and magnitude of MRA. In HF, SBRS was significantly depressed in all settings; however, the changes with exercise and MRA occurred with a pattern similar to the control state. As in control, the baroreflex stimulus-response relationship showed an intensity- and muscle metaboreflex (MMR)-dependent rightward and upward shift. The results of this study indicate that HF induces an impairment in baroreflex control of HR at rest and during exercise, although the effects of exercise and MRA on SBRS occur with a similar pattern as in control, indicating the persistence of some vagal activity.
2007
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore MED/09 - MEDICINA INTERNA
English
Con Impact Factor ISI
Autonomic; Blood pressure; Nervous system; Skeletal muscle afferents
Iellamo, F., Sala Mercado, J.a., Ichinose, M., Hammond, R.l., Pallante, M., Ichinose, T., et al. (2007). Spontaneous baroreflex control of heart rate during exercise and muscle metaboreflex activation in heart failure. AMERICAN JOURNAL OF PHYSIOLOGY. HEART AND CIRCULATORY PHYSIOLOGY, 293(3), H1929-H1936 [10.1152/ajpheart.00564.2007].
Iellamo, F; Sala Mercado, Ja; Ichinose, M; Hammond, Rl; Pallante, M; Ichinose, T; Stephenson, Lw; O'Leary, Ds
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/36063
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