Muscle sympathetic nerve activity and ventilation during exercise in subjects with and without chronic heart failure

Heat stress evokes significant increases in muscle sympathetic nerve activity (MSNA) in healthy individuals. The MSNA response to heat stress in chronic heart failure (CHF) is unknown. We hypothesized that the MSNA response to heat stress is attenuated in CHF. Passive whole body heating was applied with water-perfused suits in 13 patients (61 ± 2 yr) with stable class II-III CHF, 12 age-matched (62 ± 2 yr) healthy subjects, and 14 young (24 ± 1 yr) healthy subjects. Mild heating (i.e., increases in skin temperature ΔTsk ~2–4°C, internal temperature ΔTcore <0.3°C) significantly decreased MSNA in CHF patients; however, it did not significantly alter the MSNA in the age-matched and young healthy subjects. Heat stress (i.e., ΔTsk ~4°C and ΔTcore ~0.6°C) raised MSNA in the age-matched (32.9 ± 3.2 to 45.6 ± 4.2 bursts/min; P < 0.001) and young (14.3 ± 1.7 to 26.3 ± 2.4 bursts/min; P < 0.001) controls, but not in CHF (46.2 ± 5.3 to 50.5 ± 5.3 bursts/min; P = 0.06). The MSNA increase by the heat stress in CHF (Δ4.2 ± 2.0 bursts/min) was significantly less than those seen in the age-matched (Δ12.8 ± 1.7 bursts/min, P < 0.05) and young (Δ12.0 ± 2.7 bursts/min, P < 0.05) control groups. These data suggest that the MSNA response to heat stress is attenuated in CHF patients. We speculate that the attenuated MSNA response to heat stress may contribute to impaired cardiovascular adjustments in CHF in a hot environment.

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Altered firing pattern of single-unit muscle sympathetic nerve activity during handgrip exercise in chronic heart failure

The Journal of Physiology ◽

10.1113/jphysiol.2009.172627 ◽

2009 ◽

Vol 587 (11) ◽

pp. 2613-2622 ◽

Cited By ~ 30

Author(s):

Hisayoshi Murai ◽

Masayuki Takamura ◽

Michirou Maruyama ◽

Manabu Nakano ◽

Tatsunori Ikeda ◽

...

Keyword(s):

Heart Failure ◽

Chronic Heart Failure ◽

Sympathetic Nerve ◽

Single Unit ◽

Firing Pattern ◽

Sympathetic Nerve Activity ◽

Muscle Sympathetic Nerve Activity ◽

Handgrip Exercise ◽

Nerve Activity

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P-42 Arterial Baroreflex Control of Single-Unit Muscle Sympathetic Nerve Activity in Chronic Heart Failure with Atrial Fibrillation

CVD Prevention and Control ◽

10.1016/s1875-4570(09)60236-9 ◽

2009 ◽

Vol 4 ◽

pp. S64

Author(s):

Tatsunori Ikeda ◽

Masayuki Takamura ◽

Hisayoshi Murai ◽

Jyunichirou Inomata ◽

Daisuke Kobayashi ◽

...

Keyword(s):

Heart Failure ◽

Atrial Fibrillation ◽

Chronic Heart Failure ◽

Sympathetic Nerve ◽

Single Unit ◽

Sympathetic Nerve Activity ◽

Muscle Sympathetic Nerve Activity ◽

Arterial Baroreflex ◽

Nerve Activity ◽

Baroreflex Control

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Respiratory Modulation of Muscle Sympathetic Nerve Activity in Patients With Chronic Heart Failure

Circulation ◽

10.1161/hc2901.093111 ◽

2001 ◽

Vol 104 (4) ◽

pp. 418-423 ◽

Cited By ~ 77

Author(s):

Yukiko Goso ◽

Hidetsugu Asanoi ◽

Hisanari Ishise ◽

Tomoki Kameyama ◽

Tadakazu Hirai ◽

...

Keyword(s):

Heart Failure ◽

Chronic Heart Failure ◽

Sympathetic Nerve ◽

Sympathetic Nerve Activity ◽

Muscle Sympathetic Nerve Activity ◽

Nerve Activity ◽

Respiratory Modulation

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Abstract 17981: Decreased Oscillatory Pattern of Sympathetic Nerve Activity is Associated With Arterial Baroreflex Dysfunction in Chronic Heart Failure Patients

Circulation ◽

10.1161/circ.132.suppl_3.17981 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Edgar Toschi-Dias ◽

Raphaela V Groehs ◽

Ligia M Antunes-Correa ◽

Patrícia F Trevizan ◽

Denise M Lobo ◽

...

Keyword(s):

Heart Failure ◽

Chronic Heart Failure ◽

Ejection Fraction ◽

Sympathetic Nerve ◽

Sympathetic Nerve Activity ◽

Muscle Sympathetic Nerve Activity ◽

Inverse Association ◽

Arterial Baroreflex ◽

Nerve Activity ◽

Oscillatory Pattern

Background: Sympathetic activation and arterial baroreflex (ABR) dysfunction typify chronic heart failure (CHF). In addition, decreased oscillatory pattern of muscle sympathetic nerve activity (MSNA, LF MSNA /HF MSNA ) seems to contribute to sympathetic exacerbation in patients with CHF. Unknown is whether the LF MSNA /HF MSNA is associated with ABR dysfunction in CHF patients. To answer this question, we investigated the association between gain, latency and coupling of ABR function and LF MSNA /HF MSNA in CHF patients. Methods and Results: Forty-three CHF patients, Functional Class II to III, NYHA, ejection fraction ≤40% were allocated into two groups according to the level of LF MSNA /HF MSNA index: 1) Higher LF MSNA /HF MSNA (n=21, 52±2 years) and 2) Lower LF MSNA /HF MSNA (n=22, 54±1 years). Blood pressure (BP, oscillometric beat-to-beat basis) and MSNA (microneurography technique) were recorded during 10 min at rest. Spectral and cross-spectral analyses of BP and MSNA variabilities were conducted to assess the LF MSNA /HF MSNA and the gain, latency and coupling between BP and MSNA of ABR function. Etiology, ejection fraction, gain and latency of ABR function were similar between groups. However, the patients with lower LF MSNA /HF MSNA had increased MSNA bursts frequency (53±2vs. 39±3 bursts/min, P<0.01) and total activity (180±15 vs. 126±17 a.u, P=0.03) compared to the patients with higher LF MSNA /HF MSNA . In contrast, the patients with lower LF MSNA /HF MSNA had reduced coupling of ABR function (69±3 vs. 80±2 %, P<0.01). Further analysis showed a significant association between the coupling of ABR function and LF MSNA /HF MSNA (R=0.36, P=0.02). Conclusions: There is an inverse association between the LF MSNA /HF MSNA index and sympathetic nerve activity. In addition, there is a direct association between the LF MSNA /HF MSNA index and the coupling of ABR, which suggests that the ABR dysfunction explains, at least in part, the augmented sympathetic nerve activity in CHF patients.

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