Multi-Scale Fractal Dimension to Quantify Heart Rate Variability and Systolic Blood Pressure Variability: A Postural Stress Analysis

2019 ◽  
Vol 18 (04) ◽  
pp. 1950019 ◽  
Author(s):  
Vikramjit Singh ◽  
Amit Gupta ◽  
J. S. Sohal ◽  
Amritpal Singh
Keyword(s):  
Blood Pressure ◽  
Healthy Volunteers ◽  
Supine Position ◽  
Blood Pressure Variability ◽  
Standing Position ◽  
Multi Scale ◽  
Postural Stress ◽  
Difference Formula ◽  
Significant Difference ◽  
Systolic Blood Pressure Variability

This paper presents multi-scale fractal dimension (MFD) for the complexity assessment of heart rate variability (HRV) and systolic blood pressure variability (SBPV) under postural stress. A comparison of MFD with multi-scale approximate entropy (MAE) at multiple time scales ([Formula: see text]–10) is presented. The simulations were conducted on 50 random noise (RN), fractional Brownian motion (fBm), and MIX(p) [ 1 ] series along with standard EuroBaVar dataset. Also, 50 healthy volunteers, 20 post-acute myocardial infarction (AMI) patients participated in the study. It is observed that MFD and MAE decrease with [Formula: see text] for healthy volunteers and remained constant for post AMI and BRS failure patients. Average MFD of HRV in supine position is always significantly different than standing position scale except [Formula: see text], whereas the average MAE of HRV shows no significant difference ([Formula: see text]) between supine and standing postures at each [Formula: see text] except [Formula: see text] for healthy volunteers. Average MFD of HRV in supine position is significantly different than the standing position for [Formula: see text]–7, whereas the average MAE of HRV shows significant difference ([Formula: see text]) between supine and standing postures at [Formula: see text] for post AMI, and patients with impaired baroreflex sensitivity (BRS). Average MFD of SBPV in position is significantly different ([Formula: see text]) than standing position at each [Formula: see text], whereas the average MAE of SBPV shows no significant difference ([Formula: see text]) between supine and standing postures at each [Formula: see text] except [Formula: see text]. The complexity of HRV in standing position is less than that of supine position as shown by lower MFD and MAE values in standing than that of supine position, however, the complexity of SBPV decreases from standing to supine position indicating prevalence of sympathetic control.

Long term habitual vigorous physical activity is associated with lower visit-to-visit systolic blood pressure variability

2020 ◽  
Author(s):  
Xiaoyong Xu ◽  
Xianghong Meng ◽  
Shin-ichi Oka
Keyword(s):  
Physical Activity ◽  
Blood Pressure ◽  
Standard Deviation ◽  
Systolic Blood Pressure ◽  
Blood Pressure Variability ◽  
Vigorous Physical Activity ◽  
Systolic Blood Pressure Variability ◽  
Average Real Variability ◽  
Post Hoc

Abstract Objective Our work aimed to investigate the association between vigorous physical activity and visit-to-visit systolic blood pressure variability (BPV). Methods We conducted a post hoc analysis of SPRINT (Systolic Blood Pressure Intervention Trial), a well-characterized cohort of participants randomized to intensive (<120 mmHg) or standard (<140 mmHg) SBP targets. We assessed whether patients with hypertension who habitually engage in vigorous physical activity would have lower visit-to-visit systolic BPV compared with those who do not engage in vigorous physical activity. Visit-to-visit systolic BPV was calculated by standard deviation (SD), average real variability (ARV), and standard deviation independent of the mean (SDIM) using measurements taken during the 1-, 2-, 3-, 6-, 9- and 12-month study visits. A medical history questionnaire assessed vigorous physical activity, which was divided into three categories according to the frequency of vigorous physical activity. Results A total of 7571 participants were eligible for analysis (34.8% female, mean age 67.9±9.3 years). During a follow-up of 1-year, vigorous physical activity could significantly reduce SD, ARV, and SDIM across increasing frequency of vigorous physical activity. There were negative linear trends between frequency of vigorous physical activity and visit-to-visit systolic BPV. Conclusions Long-term engagement in vigorous physical activity was associated with lower visit-to-visit systolic BPV.

scholarly journals Correction: Prognostic impact of systolic blood pressure variability in people with diabetes

PLoS ONE ◽  
2019 ◽  
Vol 14 (10) ◽  
pp. e0224538
Author(s):  
Katy J. L. Bell ◽  
Lamiae Azizi ◽  
Peter M. Nilsson ◽  
Andrew Hayen ◽  
Les Irwig ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Blood Pressure Variability ◽  
Prognostic Impact ◽  
Systolic Blood Pressure Variability

Feedback effects of circulating norepinephrine on sympathetic outflow in healthy subjects

2005 ◽  
Vol 288 (2) ◽  
pp. H710-H715 ◽  
Author(s):  
Mikko P. Tulppo ◽  
Heikki V. Huikuri ◽  
Elli Tutungi ◽  
Derek S. Kimmerly ◽  
Adrian W. Gelb ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Sympathetic Activity ◽  
Healthy Subjects ◽  
Blood Pressure Variability ◽  
Feedback Inhibition ◽  
Adrenergic Blockade ◽  
Sympathetic Outflow ◽  
Systolic Blood Pressure Variability ◽  
Normalized Units

The amplitude of low-frequency (LF) oscillations of heart rate (HR) usually reflects the magnitude of sympathetic activity, but during some conditions, e.g., physical exercise, high sympathetic activity results in a paradoxical decrease of LF oscillations of HR. We tested the hypothesis that this phenomenon may result from a feedback inhibition of sympathetic outflow caused by circulating norepinephrine (NE). A physiological dose of NE (100 ng·kg−1·min−1) was infused into eight healthy subjects, and infusion was continued after α-adrenergic blockade [with phentolamine (Phe)]. Muscle sympathetic nervous activity (MSNA) from the peroneal nerve, LF (0.04–0.15 Hz) and high frequency (HF; 0.15–0.40 Hz) spectral components of HR variability, and systolic blood pressure variability were analyzed at baseline, during NE infusion, and during NE infusion after Phe administration. The NE infusion increased the mean blood pressure and decreased the average HR ( P < 0.01 for both). MSNA (10 ± 2 vs. 2 ± 1 bursts/min, P < 0.01), LF oscillations of HR (43 ± 13 vs. 35 ± 13 normalized units, P < 0.05), and systolic blood pressure (3.1 ± 2.3 vs. 2.0 ± 1.1 mmHg2, P < 0.05) decreased significantly during the NE infusion. During the NE infusion after PHE, average HR and mean blood pressure returned to baseline levels. However, MSNA (4 ± 2 bursts/min), LF power of HR (33 ± 9 normalized units), and systolic blood pressure variability (1.7 ± 1.1 mmHg2) remained significantly ( P < 0.05 for all) below baseline values. Baroreflex gain did not change significantly during the interventions. Elevated levels of circulating NE cause a feedback inhibition on sympathetic outflow in healthy subjects. These inhibitory effects do not seem to be mediated by pressor effects on the baroreflex loop but perhaps by a presynaptic autoregulatory feedback mechanism or some other mechanism that is not prevented by a nonselective α-adrenergic blockade.

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