Power spectrum analysis of heart rate variability to assess the changes in sympathovagal balance during graded orthostatic tilt.

Montano, Nicola; Ruscone, Tomaso Gnecchi; Porta, Alberto; Lombardi, Federico; Pagani, Massimo; Malliani, Alberto

doi:10.1161/01.cir.90.4.1826

Cited by 966 publications

(769 citation statements)

References 28 publications

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“…The normalisation of LF and HF was obtained by subtracting from total power the very low frequency component. This calculation is useful when evaluating the effects of different interventions in the same subject or when comparing subjects with major differences in total power [24].…”

Section: Subjects Materials and Methodsmentioning

confidence: 99%

The effect of insulin on cardiac autonomic balance predicts weight reduction after gastric bypass

et al. 2005

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Aims/hypothesis: The aim of this study was to assess the predictive role of autonomic reactivity in body weight loss induced by gastric bypass. Methods: A group of 22 morbidly obese subjects, who were due to undergo a gastric bypass, were submitted, before surgery, to a euglycaemic-hyperinsulinaemic clamp, during which a continuous recording of the ECG was performed. The effect of insulin on cardiac autonomic balance was evaluated by performing power spectral analysis of heart rate variability. The low-to-high frequency ratio was calculated before and during the clamp and its modifications were expressed as % delta low-to-high frequency ratio (%Δ L: H). Results: Preoperative %Δ L: H showed a significant (p=0.0009, r 2 =0.43), positive relationship to the reduction of body weight, measured 1 year after surgery and expressed as % excess weight loss (% EWL). Preoperative BMI was also significantly (p=0.0009, r 2 =0.43) negatively related to the 12-month % EWL. In a multiple regression analysis, %Δ L: H remained a significant (p=0.003), independent predictor of body weight loss, even when preoperative BMI or age, % fat mass, insulinaemia and glucose disposal were taken into account. Conclusions/ interpretation: The best correction of excess body weight was achieved by those obese subjects who had a preserved capacity to shift their cardiac autonomic balance towards a sympathetic prevalence in response to an euglycaemichyperinsulinaemic clamp. Further studies are needed to elucidate the mechanisms through which the autonomic nervous system influences weight reduction.

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Section: Subjects Materials and Methodsmentioning

confidence: 99%

The effect of insulin on cardiac autonomic balance predicts weight reduction after gastric bypass

et al. 2005

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“…Interestingly, previous studies have shown that a simple functional manoeuvre like slow deep-breathing can increase the BRS [17][18][19], an important and well-established prognostic index, and also reduce the sympathetic tone in conditions like heart failure, hypertension and chronic obstructive pulmonary disease [20][21][22]. In contrast, the upright posture increases sympathetic activity and reduces the BRS [23].…”

Section: Introductionmentioning

confidence: 99%

Early autonomic dysfunction in type 1 diabetes: a reversible disorder?

et al. 2009

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Aims/hypothesis Cardiac autonomic neuropathy is associated with increased morbidity and mortality rates in patients with type 1 diabetes. The prevalence of early autonomic abnormalities is relatively high compared with the frequency of manifest clinical abnormalities. Thus, early autonomic dysfunction could to some extent be functional and might lead to an organic disease in a subgroup of patients only. If this is true, manoeuvres such as slow deep-breathing, which can improve baroreflex sensitivity (BRS) in normal but not in denervated hearts, could also modify autonomic modulation in patients with type 1 diabetes, despite autonomic dysfunction.Methods We compared 116 type 1 diabetic patients with 36 matched healthy control participants and 12 hearttransplanted participants with surgically denervated hearts. Autonomic function tests and spectral analysis of heart rate and blood pressure variability were performed. BRS was estimated by four methods during controlled (15 breaths per minute) and slow deep-breathing (six breaths per minute), and in supine and standing positions. Results Conventional autonomic function tests were normal, but resting spectral variables and BRS were reduced during normal controlled breathing in patients with type 1 diabetes. However, slow deep-breathing improved BRS in patients with type 1 diabetes, but not in patients with surgically denervated hearts. Standing induced similar reductions in BRS in diabetic and control participants. Conclusions/interpretation Although we found signs of increased sympathetic activity in patients with type 1 diabetes, we also observed a near normalisation of BRS with a simple functional test, indicating that early autonomic derangements are to a large extent functional and potentially correctable by appropriate interventions.

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“…Extensive experimental and clinical evidence has shown that high frequency (HF) is synchronous with the respiratory cycle and mainly supported by vagal activity, whereas low frequency (LF) is largely correlated with sympathetic efferent activity. [7][8][9] In the present study, we used HRV as a strategy to study the sympathetic and vagal controls during sustained handgrip exercise in obese individuals with 12Glu9 deletion polymorphism of the a 2B -AR gene. Previous investigations using HRV analysis [10][11][12][13][14] and measurements of plasma catecholamines 15,16 showed altered sympathetic responsiveness during cold exposure, spicy food containing capsaicin and glucose ingestion in obese individuals.…”

Section: Introductionmentioning

confidence: 99%

α2B-Adrenergic receptor deletion polymorphism and cardiac autonomic nervous system responses to exercise in obese women

et al. 2005

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Objective: To investigate the association of short form (Glu 9 /Glu 9 ) of the 12Glu9 deletion polymorphism of the a 2B -adrenergic receptor (a 2B -AR) gene polymorphism with the cardiac autonomic responsiveness during sustained isometric handgrip exercise. Design: Cross-sectional clinical study. Subjects: In all, 97 normotensive obese women (body mass index (BMI) ¼ 33.2 kg/m 2 ). Of these, 78 (80.41%) were genotyped as Glu 12 /Glu 12 , 13 (13.40%) as Glu 12 /Glu 9 and six (6.19%) as Glu 9 /Glu 9 form. Measurements: The sympathovagal balance was assessed by means of power spectral analysis of heart rate variability at rest and during sustained isometric handgrip exercise at 30% of maximal voluntary handgrip contraction for 3 min. Two spectral components were analysed: low-frequency component reflecting sympathetic efferent activity and high-frequency power (HFnu) reflecting parasympathetic modulation. In addition, a normalized low-frequency power (LFnu) and HFnu were analysed. Genotypes were determined by polymerase chain reaction followed by agarose gel electrophoresis. Results: There were no differences in baseline measurements among groups. The absolute level of LFnu throughout handgrip exercise was significantly lower in Glu 9 /Glu 9 subjects compared with other genotypes, while the decline of absolute HFnu was significantly smaller compared with Glu 12 /Glu 12 genotype. Conclusion: These findings suggest that 12Glu9 deletion polymorphism of the a 2B -AR gene (Glu 9 /Glu 9 genotype) might result in reduced autonomic responsiveness by altering cardiac sympathetic and vagal function during sustained handgrip exercise in normotensive obese women.

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Power spectrum analysis of heart rate variability to assess the changes in sympathovagal balance during graded orthostatic tilt.

Abstract: Spectral analysis of HRV, using nu or LF-to-HF ratio, appears to be capable of providing a noninvasive quantitative evaluation of graded changes in the state of the sympathovagal balance.

Cited by 966 publications

References 28 publications

The effect of insulin on cardiac autonomic balance predicts weight reduction after gastric bypass

The effect of insulin on cardiac autonomic balance predicts weight reduction after gastric bypass

Early autonomic dysfunction in type 1 diabetes: a reversible disorder?

α2B-Adrenergic receptor deletion polymorphism and cardiac autonomic nervous system responses to exercise in obese women

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