Standard Deviation Of All Normal RR Intervals Research Articles

Predictive value of heart rate variability and electrochemical skin conductance measurements for cardiovascular autonomic neuropathy persistence in type 2 diabetes and prediabetes: A 3-year follow-up study

ObjectiveThe study aimed to explore risk stratification approaches for cardiovascular autonomic neuropathy (CAN) in individuals with prediabetes and type 2 diabetes (T2DM) over a three-year follow-up period. MethodsParticipants underwent evaluations of autonomic function encompassing cardiovascular autonomic reflex tests (CARTs), baroreflex sensitivity (BRS), heart rate variability (HRV) in time domains (standard deviation of all normal RR intervals (SDNN)) and frequency domains (high frequency/low frequency ratio), and electrochemical skin conductance (ESC). The diagnosis of CAN relied on abnormal CART results. Subjects were categorized into 4 groups, based on their assessment of cardiac autonomic function at 3-year follow-up, relative to the presence or absence of CAN at baseline assessment: Persistent absence of CAN; Resolution of CAN; Progression to CAN; and Persistent CAN. ResultsParticipants with T2DM/prediabetes (n = 91/7) were categorized as: Persistent absence of CAN (n = 25), Resolution of CAN (n = 10), Progression to CAN (n = 18), and Persistent CAN (n = 45) groups. The Persistent absence of CAN group showed significant associations with SDNN. The Resolution of CAN group exhibited notable associations with mean HbA1C (follow-up), while the Progression to CAN group displayed a significant link with baseline estimated glomerular filtration rate. The Persistent CAN group demonstrated significant associations with SDNN and Sudoscan CAN risk score. Screening recommendations involve biennial to annual assessments based on risk levels, aiding in CAN detection and subsequent comprehensive and time-intensive autonomic function tests for confirmation. The study's findings offer improved risk categorization approaches for detecting CAN, which has relevance for shaping public health strategies.

Effect of cognitive processing therapy on markers of cardiovascular risk in posttraumatic stress disorder patients: A randomized clinical trial

ObjectivePosttraumatic stress disorder (PTSD) is associated with elevated risk of coronary heart disease (CHD); however, the effects of PTSD treatment on CHD biomarkers is unknown. This study examined whether cognitive processing therapy (CPT) improves 24-hourheart rate variability (HRV), a predictor of CHD mortality. MethodsIndividuals between the ages of 40 and 65 years with PTSD (n = 112) were randomized to receive 12 sessions of CPT or a Waiting List (WL) intervention comprised of 6 weekly telephone checks of emotional status. The primary outcome variable was 24-hour HRV estimated from the standard deviation of all normal R-R intervals (SDNN); secondary outcomes were the root mean square of successive differences between heart beats (RMSSD), low-frequency HRV (LF-HRV) and high-frequency HRV (HF-HRV). Secondary outcomes also included 24-hour urinary catecholamine excretion, plasma C-reactive protein (CRP), and flow-mediated dilation (FMD) of the brachial artery. For outcomes, linear mixed longitudinal models were used to estimate mean differences (Mdiff). ResultsParticipants randomized to the CPT group did not show improved SDNN (Mdiff = 9.8; 95%CI, −2.7 to 22.3; p = 0.12), the primary outcome variable, but showed improved RMSSD (Mdiff = 3.8; 95% CI, 0.5 to 7.1; p = 0.02), LF- HRV (Mdiff =0.3; 95% CI, 0.1 to 0.5; p = 0.01), and HF-HRV (Mdiff = 0.3; 95% CI, 0.0 to 0.6; p = 0.03) compared to WL. There were no differences between groups in catecholamine excretion, FMD, or inflammatory markers. ConclusionTreating PTSD may not only improve quality of life but may also help ameliorate heightened CHD risk characteristics of PTSD.

Association between occupational noise exposure duration and heart rate variability among Chinese adults: The role of plasma miRNAs

We aimed to explore the association between occupational noise exposure duration and heart rate variability (HRV) and the underlying mechanism. A total of 449 subjects in a manufacturing company in Wuhan, China were included in our study and six candidate miRNAs (miR-200a-3p, miR-200b-3p, miR-200c-3p, miR-1-3p, miR-92a-3p and miR-21–5p) were tested among 200 individuals. Information combining the work histories and the occupational noise monitoring records were used to calculate the exposure of occupational noise, HRV indices were measured by using 3-channel digital Holter monitors, including the standard deviation of all normal R-R intervals (SDNN), the root mean of the square of successive differences between adjacent normal NN intervals (r-MSSD), SDNN index, low-frequency power (LF), high-frequency power (HF) and TP (total power). We found a significant linear negative dose-response relationship between occupational noise exposure duration and HRV indices (P for overall <0.05, P for nonlinear >0.05), including SDNN, r-MSSD, SDNN index, LF and HF. In the continuous models, the β (95% CIs) for each 1-year occupational noise exposure were −0.002 (−0.004, −0.001) for SDNN, −0.002 (−0.004, −0.001) for r-MSSD, −0.002 (−0.004, −0.001) for SDNN index, and −0.006 (−0.012, −0.001) for HF. Meanwhile, we also found that occupational noise exposure duration was significantly associated with lower expression of five miRNAs, when adjusting for other covariates. The β (95% CIs) were −0.039 (−0.067, −0.011) for miRNA-200c-3p, −0.053 (−0.083, −0.022) for miRNA-200a-3p, −0.044 (−0.070, −0.019) for miRNA-200b-3p, −0.032 (−0.048, −0.017) for miRNA-92a-3p, and −0.063 (−0.089, −0.038) for miRNA-21–5p in the continuous models. In addition, we found a positive association between miRNA-1-3p and LF (β = 0.039, 95% CI = 0.002, 0.080). Our study suggests that occupational noise exposure duration is associated with cardiac autonomic dysfunction, and the role of miRNAs in noise induced HRV reduction needs to be confirmed in future studies.

Association Between Physical Activity Levels in Different Domains and Cardiac Autonomic Modulation in Breast Cancer Survivors: A Cross-sectional Study.

Breast cancer survivors frequently present cardiac autonomic dysfunction. Physical activity (PA) has been associated with better cardiac autonomic modulation (CAM) in breast cancer survivors. This study aimed to analyze the association between CAM and PA levels performed in different domains (work and occupation, sport and exercise, and leisure time and commuting) in breast cancer survivors. This is a cross-sectional study with 99 breast cancer survivors (age, 55.3 ± 10.4 years). Cardiac autonomic modulation was assessed by heart rate variability, and PA levels at work and occupation, sport and exercise, and leisure time and commuting were assessed using the Baecke PA questionnaire. The sum of these 3 domains provided the total PA. The Mann-Whitney test was used to compare CAM between active and inactive women in different domains of PA. Cardiac autonomic modulation was similar between active and inactive women in the different domains ( P > .05). However, when considering the total PA, active breast cancer survivors presented higher SDNN (average standard deviation of all normal RR intervals) (20.0 ± 13.4 vs 28.8 ± 14.0; P = .008) and SD2 (standard deviation of the long-term intervals between consecutive heartbeats) indices (29.2 ± 17.3 vs 38.7 ± 19.9; P = .005) compared with their inactive counterparts. Breast cancer survivors with higher total PA presented better CAM compared with their less active peers. The results of this study are promising and show the importance of increasing PA levels in different domains for the maintenance of cardiovascular health among breast cancer survivors.

Polyunsaturated Fatty Acid EAB-277® Supplementation Improved Heart Rate Variability and Clinical Signs in Tracheal Collapse Dogs.

Canine tracheal collapse is a progressive disease in small breed dogs resulting from chronic inflammation of the tracheal mucosal lining. Polyunsaturated fatty acid EAB-277® is one of the nutraceuticals that can alleviate inflammation and oxidative stress. Heart rate variability (HRV) is a prognostic tool related to sympathovagal balance and oxidative stress level, which is widely used with cardiorespiratory diseases. However, the effect of EAB-277® on HRV in tracheal collapse dogs has rarely been investigated. In this study, 26 tracheal collapse dogs were divided into two groups. In the control group, the dogs received the standard treatment, whereas the dogs in the EAB-277® group received standard treatment combined with EAB-277®. After being treated for 5 weeks, changes in radiographic findings, blood profiles, serum malondialdehyde, inflammatory markers, and HRV were evaluated. This study found that clinical signs were improved in both groups (p < 0.05). However, serum malondialdehyde (MDA), Interleukin-6 (IL-6), and Tumor necrosis factor-alpha (TNF-α) were decreased only in the EAB-277® group after treatment for five weeks (p < 0.05) and the mean percent change of MDA, IL-6, and TNF-α at week five compared to baseline in the EAB-277® group was greater than in the control group (p < 0.05). Additionally, greater sympathovagal imbalance indicated by decreased standard deviation of all normal R-R intervals (SDNN) and standard deviation of the averaged R-R intervals for all 5-minutes segments (SDANN) was found in the control group at week five compared to baseline (P < 0.05), whereas EAB-277® improved SDNN and SDANN and decreased low frequency/high-frequency component (LF/HF ratio) after being treated for five weeks (P < 0.05). This study demonstrates that EAB-277® improves clinical signs and attenuates HRV impairment by reducing oxidative stress and inflammation in tracheal collapse dogs.

Premature cardiac beats in children with structurally normal heart: autonomic dysregulation.

Premature ventricular contractions and supraventricular contractions are common rhythm disorders requiring comprehensive investigation in children. The aim of the study was to evaluate the heart rate variability (HRV) in premature ventricular contractions (PVCs) and supraventricular contractions (PSVCs) in children. The study compared the characteristics of HRV in 175 children with PVCs and 160 children with PSVCs who underwent 24-h Holter monitoring, with 101 healthy children. Significant differences were found between standard deviation of all normal RR intervals (SDNN), standard deviation of average RR intervals in all 5 min segments of registration (SDANN), root mean square of the successive differences (rMSSD), and the proportion of NN50 divided by total number of NNs (pNN50) values of the patient and control groups. The PVCs group had a significantly lower high frequency (HF) and higher low frequency (LF)/HF ratio and the PSVCs group had a significantly higher LF and higher LF/HF ratio compared to the control group. No significant correlation existed between frequency and the SDNN index, rMSSD, and pNN50 values of the PVCs group. The receiver operating characteristics analysis showed a significantly changed LF/HF ratio when premature contractions exceeded 60 beats per hour in children with PVCs. This study indicated an increased sympathetic tone and a significantly decreased vagal tone in children with PVCs and PSVCs. HRV can be used increasingly as a non-invasive method in the follow-up of children with premature cardiac contractions.

Influence of a 100-mile ultramarathon on heart rate and heart rate variability

AimsThis study aimed to investigate the impact of an ultramarathon (UM) with a distance of 100 miles on heart rate (HR) and heart rate variability (HRV).Methods28 runners (25 men and...

Feasibility of combining heart rate variability and electrochemical skin conductance as screening and severity evaluation of cardiovascular autonomic neuropathy in type 2 diabetes.

Aims/IntroductionClinical studies show that either heart rate variability (HRV) or electrochemical skin conductance (ESC) alone can serve as a simple and objective method for screening cardiovascular autonomic neuropathy (CAN). We tested the hypothesis that combining these two quantitative approaches can not only reinforce accuracy in CAN screening but also provide a better estimate of CAN severity in patients with type 2 diabetes (T2DM) who had already had CAN in outpatient clinics.Materials and MethodsEach patient received a complete battery of cardiovascular autonomic reflex tests (CARTs), with ESC measured by SUDOSCAN, time domain of HRV measured by standard deviation of all normal RR intervals (SDNN) and frequency domain of HRV (low frequency [LF], high frequency [HF], and LF/HF ratio), and peripheral blood studies for vascular risk factors. Severity of CAN was measured by CAN score.ResultsThe 90 T2DM patients included 50 males and 40 females. Those with more severe CAN had lower values in feet ESC (P = 0.023) and SDNN (P < 0.0001). Multiple linear regression analysis also showed that feet ESC and SDNN value (P = 0.003 and P < 0.0001) were significantly associated with CAN score. Combining SDNN and feet ESC also can increase the diagnostic accuracy of CAN with respective to sensitivity and specificity by using receiver operating characteristic analysis.ConclusionsCombining the results of SDNN and feet ESC can not only assess, but also quantitatively reflect the progress or improvement of autonomic nerve function (including sympathetic and parasympathetic activity) in patients with T2DM.

Deceleration capacity of heart rate predicts trastuzumab-related cardiotoxicity in patients with HER2-positive breast cancer: A prospective observational study.

Trastuzumab is the standard choice for anti-human epidermal growth factor receptor 2 (HER2) therapy. Cardiotoxicity is one of the main adverse effects of trastuzumab. How to early predict trastuzumab-related cardiotoxicity remains a significant problem in clinical practice. The deceleration capacity of the heart rate (DC) has been shown to be a powerful predictor of adverse outcomes in various heart diseases. In the study, the role of DC in early predicting trastuzumab-related cardiotoxicity was investigated. A total of 150 patients were prospectively investigated the clinical value of the DC in predicting trastuzumab-related cardiotoxicity in patients with HER2-positive breast cancer treated with trastuzumab at Guangxi Medical University Cancer Hospital from June 2015 to June 2017. DC, mean heart rate and heart rate variability (HRV) indices, including the standard deviation of all normal RR intervals (SDNN) and the square root of the mean of the squared differences between adjacent normal RR intervals (RMSSD), were assessed before treatment, and the left ventricular ejection fraction (LVEF) was regularly monitored for 2years (before, during and after treatment) to evaluate cardiotoxicity. Among 150 eligible patients, 28 (18.7%) developed cardiotoxicity. Patients with cardiotoxicity were older (P<.05), higher anthracycline dose (P<.001) and had lower RMSSD (P<.05), SDNN, DC and baseline LVEF (P<.001), than patients without cardiotoxicity. Logistic regression analysis revealed lower DC, lower baseline LVEF and higher anthracycline dose were independent risk factors of trastuzumab-related cardiotoxicity. Receiver operating characteristic (ROC) curve analysis revealed a greater area under the curve for DC than for the baseline LVEF in predicting cardiotoxicity (0.88 vs 0.77, P=.032). Additionally, DC had higher sensitivity (78.6% vs 67.9%) and specificity (83.6% vs 77.9%) in predicting cardiotoxicity than the baseline LVEF. Linear regression analysis showed among patients who developed cardiotoxicity, lower DC was associated with an earlier onset (P<.01). The present study found that DC was a stronger predictor of trastuzumab-related cardiotoxicity development than the baseline LVEF and HRV. Linear regression analysis showed among patients who developed cardiotoxicity, lower DC was associated with an earlier onset. DC should be a potential clinical indicator for the early prediction of trastuzumab-related cardiotoxicity.

The effect of remote ischemic postconditioning on autonomic function in patients with acute ischemic stroke: A Randomized Controlled Trail

ObjectiveThe evidence for the effect of remote ischemic postconditioning(RIpostC) on autonomic function in patients with acute ischemic stroke(AIS) is lacking and the neural mechanism underlying the protection of RIpostC remains speculative. This trial was aimed to evaluated the efficiency of RIpostC on autonomic function in AIS patients. DesignOne hundred and six AIS patients were included in this prospective, randomized, placebo-controlled trial. Patients in intervention group (n = 57) received 4 cycles of alternating inflation (cuff inflation to 200 mmHg) and deflation for 5 min on healthy upper arm once a day for 30 days. The control group underwent a sham inflation and deflation cycles. Autonomic function was evaluated by heart rate variability (HRV). ResultsAll HRV parameters except for the ratio of low frequency to high frequency (P = 0.101) increased significantly with time (P < 0.001) in the two groups. The value of standard deviation of all normal R-R intervals(SDNN) and high frequency at day7 and day30 and the value of the percent of difference between adjacent normal R-R intervals (pNN50) at day 30 in RIpostC group was significantly higher than that of the sham-RIpostC group(P < 0.05). A significant time-by-group interaction was observed in SDNN、pNN50、and high frequency over time between two groups (P < 0.05). Conclusions30-day RIpostC could improve autonomic function in AIS patients through the enhancement of the total autonomic nerve activity and vagus nerve activity. The mechanism of RIpostC mediating autonomic function needs to be further investigated.

Correction: Autonomic Dysfunction is Associated with Increased Cardiometabolic Risk in Patients with Childhood-Onset Craniopharyngioma.

Patients with craniopharyngioma are susceptible to autonomic dysfunction as a result of hypothalamic damage. We evaluated indices of heart rate variability (HRV) in patients with childhood-onset craniopharyngioma to investigate autonomic function and its relationship with components of the metabolic syndrome (MetS). This cross-sectional, case-only study included 53 patients (10–30 years of age). We measured the standard deviation of all normal R-R intervals (SDNN) and total power indicating overall HRV, the root-mean square of the difference of successive R-R intervals (RMSSD) and high frequency indicating parasympathetic modulation, and low frequency. These indices were compared according to the presence of the MetS. During the mean 10.8 years of follow-up, 25% of patients were diagnosed with the MetS. Patients with the MetS showed significantly lower levels of SDNN (29.0 vs. 40.6 ms), total power (416.1 vs. 1129.6 ms2), RMSSD (20.1 vs. 34.5 ms), high frequency (94.7 vs. 338.5 ms2), and low frequency (94.5 vs. 289.4 ms2) than those without (p <0.05, for all). Individual components of the MetS including insulin resistance, serum triglycerides levels, and systolic blood pressure were inversely associated with SDNN, total power, RMSSD and high frequency. Higher overall variability and parasympathetic modulation were related to decreased odds ratios for having the MetS (OR 0.91, p=0.029 for SDNN; OR 0.91, p=0.032 for total power). In conclusion, autonomic dysfunction, as evidenced by reduced HRV indices, is associated with increased cardiometabolic risk in patients with childhood-onset craniopharyngioma.

Autonomic Dysfunction is Associated with Increased Cardiometabolic Risk in Patients with Childhood-Onset Craniopharyngioma.

Patients with craniopharyngioma are susceptible to autonomic dysfunction as a result of hypothalamic damage. We evaluated indices of heart rate variability (HRV) in patients with childhood-onset craniopharyngioma to investigate autonomic function and its relationship with components of the metabolic syndrome (MetS). This cross-sectional, case-only study included 53 patients (10-30 years of age). We measured the standard deviation of all normal R-R intervals (SDNN) and total power indicating overall HRV, the root-mean square of the difference of successive R-R intervals (RMSSD) and high frequency indicating parasympathetic modulation, and low frequency. These indices were compared according to the presence of the MetS. During the mean 10.8 years of follow-up, 25% of patients were diagnosed with the MetS. Patients with the MetS showed significantly lower levels of SDNN (29.0 vs. 40.6 ms), total power (416.1 vs. 1129.6 ms2), RMSSD (20.1 vs. 34.5 ms), high frequency (94.7 vs. 338.5 ms2), and low frequency (94.5 vs. 289.4 ms2) than those without (p <0.05, for all). Individual components of the MetS including insulin resistance, serum triglycerides levels, and systolic blood pressure were inversely associated with SDNN, total power, RMSSD and high frequency. Higher overall variability and parasympathetic modulation were related to decreased odds ratios for having the MetS (OR 0.91, p=0.029 for SDNN; OR 0.91, p=0.032 for total power). In conclusion, autonomic dysfunction, as evidenced by reduced HRV indices, is associated with increased cardiometabolic risk in patients with childhood-onset craniopharyngioma.

Abstract P497: Association Between Accelerometer-estimated Physical Activity Intensity and Heart Rate Variability: Mediation by Glycemic Measures and Triglycerides (from The Cardia Study)

Introduction: We estimated cross-sectional associations between accelerometer-estimated light (LPA), moderate (MPA), and vigorous (VPA) intensity physical activity (PA) and heart rate variability (HRV), and tested mediation of these associations by glycemic control indices, blood lipids, and blood pressure. Hypothesis: PA is positively and independently associated with higher (improved) HRV. Glycemic measures are partial physiological mediators of these associations. Methods: Data were from 1,668 participants (X -age = 46 ± 4 yrs, 58% F, 40% black) in Year 20 (2005-06) of the Coronary Artery Risk Development in Young Adults (CARDIA) Fitness Study. The ActiGraph 7164 estimated participants’ mean min/d of LPA, MPA, and VPA over 7d. Three sequential 10-sec 12-lead ECG strips provided standard deviation of all normal RR intervals (SDNN) and root mean square of all successive RR intervals (rMSSD) HRV. Physiological mediators included fasting glucose and insulin as well as 2-hr oral glucose tolerance (OGTT), fasting triglycerides (TG), HDL-C, and systolic blood pressure (BP). Multiple linear regression, controlling for demographic and lifestyle confounders, assessed independent associations of PA with SDNN and rMSSD HRV per 1-SD. Mediation analyses computed the proportion of the PA-HRV associations attributable to physiological mediators. Results: Participants averaged 360.2 ± 83.8, 33.0 ± 22.0, and 2.7 ± 6.2 min/d of LPA, MPA, and VPA, respectively, with mean values for SDNN (32.6 ± 22.4 ms) and rMSSD (34.0 ± 24.8 ms) similar. VPA was associated with both HRV metrics (SDNN: std = .06 [.03, .10]; rMSSD: std = .08, [.05, .12]) and LPA with rMSSD only (std = .05, [.01, .08]). Fasting glucose and insulin mediated between 11.6%-20.7% of the association of VPA and LPA with HRV (Table). Triglycerides also mediated these associations (range: 9.6%-13.4%; Table). Conclusions: Accelerometer-estimated VPA and LPA were positively associated with higher HRV. These associations may be due most to glycemia and insulinemia.

The relationship between chemotherapy-induced peripheral neuropathy and heart rate variability.

820 Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common complication related to chemotherapeutic agents and dose accumulation. Initial symptoms are known to be sensory including numbness and pain whereas autonomic symptoms are the latest. Autonomic dysfunction is related to heart rate variability (HRV) change which may precede the symptoms. But, the relationship between CIPN and heart rate variability is not fully evaluated. Therefore, we aimed to evaluate the HRV with CIPN-related questionnaires in patients underwent chemotherapy. Methods: Fifty-five patients with gastrointestinal cancers were enrolled in this cross-sectional cohort study. Patients have received chemotherapeutic agents such as paclitaxel, cisplatin, and oxaliplatin. CIPN was diagnosed using National Cancer Institute Common Toxicity Criteria for Adverse Event (NCI-CTCAE version 4.03). We evaluated the quality of life, CIPN symptom scale, and HRV. Results: Forty-two patients were male (76.4%) and mean age was 63.2 years old. Thirty-nine patients (71.0%) had CIPN of more than grade I according to NCI-CTCAE. Patients with CIPN represented lower physical and role functions. The standard deviation of all normal R-R intervals (SDNN) was decreased in the CIPN group. Parasympathetic tone (high frequency band) were decreased, but sympathetic activity (low frequency band/high frequency band) were increased in CIPN. Conclusions: CIPN affected the quality of life in gastrointestinal cancer patients underwent chemotherapy. HRV was related to CIPN. Further study may be needed to check the feasibility of HRV as early biomarkers for detecting CIPN. [Table: see text]

Impact of Using Different Levels of Threshold-Based Artefact Correction on the Quantification of Heart Rate Variability in Three Independent Human Cohorts.

Heart rate variability (HRV) is a non-invasive indicator of autonomic nervous system function. HRV recordings show artefacts due to technical and/or biological issues. The Kubios software is one of the most used software to process HRV recordings, offering different levels of threshold-based artefact correction (i.e., Kubios filters). The aim of the study was to analyze the impact of different Kubios filters on the quantification of HRV derived parameters from short-term recordings in three independent human cohorts. A total of 312 participants were included: 107 children with overweight/obesity (10.0 ± 1.1 years, 58% men), 132 young adults (22.2 ± 2.2 years, 33% men) and 73 middle-aged adults (53.6 ± 5.2 years, 48% men). HRV was assessed using a heart rate monitor during 10–15 min, and the Kubios software was used for HRV data processing using all the Kubios filters available (i.e., 6). Repeated-measures analysis of variance indicated significant differences in HRV derived parameters in the time-domain (all p < 0.001) across the Kubios filters in all cohorts, moreover similar results were observed in the frequency-domain. When comparing two extreme Kubios filters, these statistical differences could be clinically relevant, e.g. more than 10 ms in the standard deviation of all normal R-R intervals (SDNN). In conclusion, the results of the present study suggest that the application of different Kubios filters had a significant impact on HRV derived parameters obtained from short-term recordings in both time and frequency-domains.

Association between Objective Activity Intensity and Heart Rate Variability: Cardiovascular Disease Risk Factor Mediation (CARDIA).

We evaluated the associations between accelerometer-estimated physical activity (PA) intensity and heart rate variability (HRV) and examined mediation of these associations by glycemic control indices and other cardiovascular disease risk factors. Data were from 1668 participants (X[Combining Overline]age = 45.9 ± 3.5 yr, 58.0% female, 39.9% black) who participated in year 20 (2005-2006) of the Coronary Artery Risk Development in Young Adults Fitness Study. The ActiGraph 7164 estimated participants' mean minutes per day of vigorous-intensity PA (VPA), moderate-intensity PA (MPA), and light-intensity PA (LPA) over 7 d. Three sequential 10-s 12-lead ECG strips were used to derive standard deviation of all normal RR intervals (SDNN) and root mean square of all successive RR intervals (rMSSD) HRV. Mediators representing glycemic control indices included fasting glucose, fasting insulin, and 2-h oral glucose tolerance, with other mediators being traditional cardiovascular disease risk factors. Multiple linear regression assessed independent associations of PA intensity with HRV per 1-SD. Mediation analyses computed the proportion of the PA-HRV association attributable to physiological mediators. Participants averaged 2.7 ± 6.2 min·d, 33.0 ± 22.0 min·d, and 360.2 ± 83.8 min·d of VPA, MPA, and LPA, respectively, with mean values for SDNN (32.6 ± 22.4 ms) and rMSSD (34.0 ± 24.8 ms) similar. After adjustment for demographic and lifestyle behaviors, VPA was associated with both HRV metrics (SDNN: std beta = 0.06 [0.03, 0.10]; rMSSD: std beta = 0.08 [0.05, 0.12]) and LPA with rMSSD only (std beta = 0.05 [0.01, 0.08]). Fasting insulin and glucose mediated 11.6% to 20.7% of the association of VPA and LPA with HRV, with triglycerides also potentially mediating these associations (range, 9.6%-13.4%). Accelerometer-estimated VPA was associated with higher (i.e., improved) HRV. Light-intensity PA also demonstrated a positive association. Mediation analyses suggested these associations may be most attributable to glucose-insulin dynamics.

Effects of 16-Form Wheelchair Tai Chi on the Autonomic Nervous System among Patients with Spinal Cord Injury.

Objective This study aims to investigate the effects of 16-form Wheelchair Tai Chi (WCTC16) on the autonomic nervous system among patients with spinal cord injury (SCI). Methods Twenty patients with chronic complete thoracic SCI were recruited. Equivital life monitoring system was used to record and analyze heart rate variability (HRV) of patients for five minutes before and after five consecutive sets of WCTC16, respectively. The analysis of HRV in the time domain included RR intervals, the standard deviation of all normal RR intervals (SDNN), and the root mean square of the differences between adjacent NN intervals (RMSSD). The analysis of HRV in the frequency domain included total power (TP), which could be divided into very-low-frequency area (VLFP), low-frequency area (LFP), and high-frequency area (HFP). The LF/HF ratio as well as the normalized units of LFP (LFPnu) and HFP (HFPnu) reflected the sympathovagal balance. Results There was no significant difference in RR interval, SDNN, RMSSD, TP, HEP, VLFP, and LFP of SCI patients before and after WCTC16 exercise (P > 0.05). LFPnu and HF peak decreased, while HFPnu and LF/HF increased in SCI patients after WCTC16 exercise. The differences were statistically significant (P < 0.001). Conclusion WCTC16 can enhance vagal activity and decrease sympathetic activity so that patients with chronic complete thoracic SCI can achieve the balanced sympathovagal tone.

Effects of Respiratory Rate on Heart Rate Variability in Neurologic Outpatients with Epilepsies or Migraine: A Preliminary Study

Background: Variation of spontaneous respiratory rates and influences of spontaneous and paced breathing rates on heart rate variability (HRV) were assessed in patients with epilepsy or migraine, and HRV parameters were compared between the groups. Materials and Methods: Thirty neurologic outpatients, 16 diagnosed with epilepsies and 14 with migraine, were included. Autonomic testing consisted of short-term HRV, the deep breathing test (DBT), and measurement of HRV at systematically changed breathing rates (paced breathing, 5–18 breaths per minute, bpm). Results: Spontaneous respiratory rate during short-term HRV varied from 9 to 23 bpm in the epileptic group and from 5 to 21 bpm in migraine patients and was significantly and negatively correlated with SD of all normal RR intervals (SDNN) and total power (TP) in epileptic patients but not in migraine patients. Paced breathing rate had a significant effect on all HRV parameters assessed in both groups. HRV (SD1, SDNN, TP) and DBT (E-I, SD1, SDNN) parameters were significantly lower in the epileptic group. Group differences were significantly greater during slow compared to fast breathing. Conclusions: An important and new finding is the wide variation of spontaneous respiratory rate in both groups, along with the significant negative correlation with the assessed HRV parameters. The reduction of HRV during slow breathing in epileptic patients may indicate a diminished cardiorespiratory coupling caused by a probable loss of sensitivity within the cardiovagal brainstem circuitry.

Isoflavone does not promote additional effects on heart rate variability of postmenopausal women performing combined exercise training: a clinical, controlled, randomized, double-blind study.

The aim of the study was to investigate the effects of ingesting isoflavones associated with combined aerobic and resistance exercise training on heart rate variability (HRV) indices in postmenopausal women. Twenty-eight healthy postmenopausal women performed 10 weeks of combined exercise training associated with isoflavone (n = 16) or placebo (n = 12) supplementation. The RR intervals (RRi) were collected for 20 min using a heart rate monitor. Analysis of HRV was performed in time (mean squared difference of successive RRi (RMSSD), standard deviation of all normal RRi (SDNN), and percentage of adjacent RRi differing by more than 50 ms (pNN50)), frequency (low-frequency percentage (LF%), high-frequency percentage (HF%), and low-/high-frequency ratio (LF/HF)), and nonlinear domains (standard deviation of the instantaneous variability of the beat-to-beat interval (SD1), long-term variability of the continuous RRi (SD2), and their ratio (SD2/SD1)). Student's t test did not show differences between groups in any general baseline characteristic variables. The results of the generalized estimating equation tests did not demonstrate interaction or group effects for any HRV indices. However, the results reported time effects for mean RR (p < 0.001), RMSSD (p = 0.044), and SD1 (p = 0.044), with increases in these indices in response to exercise training. There were no time effects for LF%, HF%, LF/HF, SDNN, pNN50, SD2, or SD2/SD1. In conclusion, isoflavone supplementation did not promote additional effects on HRV indices of postmenopausal women subjected to 10 weeks of combined exercise training. Novelty Combined training improves heart rate variability in postmenopausal women. Isoflavone supplementation did not promote additional effects on heart rate variability in postmenopausal women.

&lt;p&gt;Heart rate variability and incidence of depression during the first six months following first myocardial infarction&lt;/p&gt;

BackgroundPost-myocardial depression is a highly prevalent condition worsening the course and prognosis of coronary artery disease. One of the possible pathogenetic factors is dysregulation of the autonomous nervous system, resulting in heart rate variability reduction.MethodsTwenty two patients hospitalised due to a first myocardial infarction were included. The Beck Depression Inventory (BDI) was used to rate the severity of their depressive symptoms.ResultsDepressive symptomatology, defined as BDI ≥10, was present in 36.3% of the patients. Increase in heart rate variability (HRV) was observed in both groups during the first 6 months after the myocardial infarction. The HRV was significantly lower in the depressed group compared to patients without depression.ConclusionPresence of depression after the myocardial infarction (MI) is associated with a significant decrease of the time domain HRV measure SDNN (standard deviation of all normal RR intervals) and with its slower increase during at least a three months period.