scholarly journals Oscillatory Pattern of Sympathetic Nerve Bursts Is Associated With Baroreflex Function in Heart Failure Patients With Reduced Ejection Fraction

2021 ◽  
Vol 15 ◽  
Author(s):  
Edgar Toschi-Dias ◽  
Nicola Montano ◽  
Eleonora Tobaldini ◽  
Patrícia F. Trevizan ◽  
Raphaela V. Groehs ◽  
...  
Keyword(s):  
Left Ventricular Ejection Fraction ◽  
Ejection Fraction ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Nerve Activity ◽  
Ventricular Ejection Fraction ◽  
Baroreflex Function

Sympathetic hyperactivation and baroreflex dysfunction are hallmarks of heart failure with reduced ejection fraction (HFrEF). However, it is unknown whether the progressive loss of phasic activity of sympathetic nerve bursts is associated with baroreflex dysfunction in HFrEF patients. Therefore, we investigated the association between the oscillatory pattern of muscle sympathetic nerve activity (LFMSNA/HFMSNA) and the gain and coupling of the sympathetic baroreflex function in HFrEF patients. In a sample of 139 HFrEF patients, two groups were selected according to the level of LFMSNA/HFMSNA index: (1) Lower LFMSNA/HFMSNA (lower terciles, n = 46, aged 53 ± 1 y) and (2) Higher LFMSNA/HFMSNA (upper terciles, n = 47, aged 52 ± 2 y). Heart rate (ECG), arterial pressure (oscillometric method), and muscle sympathetic nerve activity (microneurography) were recorded for 10 min in patients while resting. Spectral analysis of muscle sympathetic nerve activity was conducted to assess the LFMSNA/HFMSNA, and cross-spectral analysis between diastolic arterial pressure, and muscle sympathetic nerve activity was conducted to assess the sympathetic baroreflex function. HFrEF patients with lower LFMSNA/HFMSNA had reduced left ventricular ejection fraction (26 ± 1 vs. 29 ± 1%, P = 0.03), gain (0.15 ± 0.03 vs. 0.30 ± 0.04 a.u./mmHg, P < 0.001) and coupling of sympathetic baroreflex function (0.26 ± 0.03 vs. 0.56 ± 0.04%, P < 0.001) and increased muscle sympathetic nerve activity (48 ± 2 vs. 41 ± 2 bursts/min, P < 0.01) and heart rate (71 ± 2 vs. 61 ± 2 bpm, P < 0.001) compared with HFrEF patients with higher LFMSNA/HFMSNA. Further analysis showed an association between the LFMSNA/HFMSNA with coupling of sympathetic baroreflex function (R = 0.56, P < 0.001) and left ventricular ejection fraction (R = 0.23, P = 0.02). In conclusion, there is a direct association between LFMSNA/HFMSNA and sympathetic baroreflex function and muscle sympathetic nerve activity in HFrEF patients. This finding has clinical implications, because left ventricular ejection fraction is less in the HFrEF patients with lower LFMSNA/HFMSNA.

scholarly journals Training heart failure patients with reduced ejection fraction attenuates muscle sympathetic nerve activation during mild dynamic exercise

2019 ◽  
Vol 317 (4) ◽  
pp. R503-R512 ◽  
Author(s):  
Catherine F. Notarius ◽  
Philip J. Millar ◽  
Daniel A. Keir ◽  
Hisayoshi Murai ◽  
Nobuhiko Haruki ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Sympathetic Nerve ◽  
Muscle Sympathetic Nerve Activity ◽  
Reactive Hyperemia ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ventricular Ejection Fraction ◽  
Muscle Metaboreflex ◽  
Reduced Ejection Fraction

Muscle sympathetic nerve activity (MSNA) decreases during low-intensity dynamic one-leg exercise in healthy subjects but increases in patients with heart failure with reduced ejection fraction (HFrEF). We hypothesized that increased peak oxygen uptake (V̇o2peak) after aerobic training would be accompanied by less sympathoexcitation during both mild and moderate one-leg dynamic cycling, an attenuated muscle metaboreflex, and greater skin vasodilation. We studied 27 stable, treated HFrEF patients (6 women; mean age: 65 ± 2 SE yr; mean left ventricular ejection fraction: 30 ± 1%) and 18 healthy age-matched volunteers (6 women; mean age: 57 ± 2 yr). We assessed V̇o2peak (open-circuit spirometry) and the skin microcirculatory response to reactive hyperemia (laser flowmetry). Fibular MSNA (microneurography) was recorded before and during one-leg cycling (2 min unloaded and 2 min at 50% of V̇o2peak) and, to assess the muscle metaboreflex, during posthandgrip ischemia (PHGI). HFrEF patients were evaluated before and after 6 mo of exercise-based cardiac rehabilitation. Pretraining V̇o2peak and skin vasodilatation were lower ( P < 0.001) and resting MSNA higher ( P = 0.01) in HFrEF than control subjects. Training improved V̇o2peak (+3.0 ± 1.0 mL·kg−1·min−1; P < 0.001) and cutaneous vasodilation and diminished resting MSNA (−6.0 ± 2.0, P = 0.01) plus exercise MSNA during unloaded (−4.0 ± 2.5, P = 0.04) but not loaded cycling (−1.0 ± 4.0 bursts/min, P = 0.34) and MSNA during PHGI ( P < 0.05). In HFrEF patients, exercise training lowers MSNA at rest, desensitizes the sympathoexcitatory metaboreflex, and diminishes MSNA elicited by mild but not moderate cycling. Training-induced downregulation of resting MSNA and attenuated reflex sympathetic excitation may improve exercise capacity and survival.

scholarly journals The acute effect of atrioventricular pacing on sympathetic nerve activity in patients with normal and depressed left ventricular function

2008 ◽  
Vol 295 (3) ◽  
pp. H1076-H1080 ◽  
Author(s):  
Nathan M. Segerson ◽  
Stephen L. Wasmund ◽  
Marcos Daccarett ◽  
Manuel L. Fabela ◽  
Christopher H. Hammond ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Normal Sinus Rhythm ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Nerve Activity ◽  
Ventricular Ejection Fraction ◽  
Group 2 ◽  
Group 1

Although modest elevations in pacing rate improve cardiac output and induce reflex sympathoinhibition, the threshold rate above which hemodynamic perturbations induce reflex sympathoexcitation remains unknown. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressures (MAP) and sympathetic nerve activity (SNA) were measured during normal sinus rhythm (NSR) and atrioventricular (AV) sequential pacing in 25 patients. Pacing was performed at 100, 120, and 140 beats/min with an AV interval of 100 ms. Patients were divided into two groups based on normal or abnormal left ventricular ejection fraction (LVEF): group 1 ( n = 11; mean LVEF, 55%) and group 2 ( n = 14; mean LVEF, 31%). In group 1, relative to NSR, SBP decreased an average of 2%, 3%, and 8% at 100, 120, and 140 beats/min ( P < 0.001), respectively. DBP and MAP increased 9%, 15%, and 15% ( P = 0.001) and 3%, 6%, and 5% [ P = not significant (NS)], respectively. In group 2, SBP reductions were even greater, with an average decrease of 4%, 8%, and 16% ( P < 0.001). Whereas DBP increased 9%, 9%, and 8% at 100, 120, and 140 beats/min ( P = NS), MAP increased 3% and 2% at 100 and 120 beats/min but decreased 3% at 140 beats/min ( P = 0.001). SNA recordings were obtained in 11 patients (6 in group 1 and 5 in group 2). In group 1, SNA decreased during all rates, with a mean 21% reduction. In group 2, however, SNA decreased at 100 and 120 beats/min (49% and 38%) but increased 24% at 140 beats/min. Patients with depressed LVEF exhibited altered hemodynamic and sympathetic responses to rapid sequential pacing. The implications of these findings in device programming and arrhythmia rate control await future studies.

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