Standard Deviation Of All NN Intervals Research Articles

Interplay of heart rate variability and resting heart rate on mortality in type 2 diabetes

AimsHeart rate variability (HRV) and resting heart rate (RHR) are usually analyzed and interpreted separately. We aimed to assess the interplay of HRV and RHR on mortality in type 2 diabetes. MethodsThe study included 7,529 participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. HRV metrics included standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). Abnormal values were defined based on <25th percentile for HRV and >75th percentile for RHR. Interactions of HRV status and RHR status were tested on multiplicative and additive scales. Results were validated in a subset of patients with type 2 diabetes (n = 745) from the Multi-Ethnic Study of Atherosclerosis. ResultsLow SDNN was associated with increased all-cause mortality in the high RHR group (HR 1.60; 95% CI 1.29–1.97), but not in the normal RHR group. Compared with those who had neither low SDNN nor high RHR, the presence of either low SDNN or high RHR was not significantly associated with an increased risk of all-cause mortality. In contrast, the combination of low SDNN and high RHR was associated with a significantly increased risk of all-cause mortality (HR 1.68; 95% CI 1.43–1.97). Significant multiplicative and additive interactions were found between HRV status and RHR status on risk of all-cause mortality (all Pinteraction < 0.05). Similar findings were observed for cardiovascular mortality, in analyses using rMSSD, and in the Multi-Ethnic Study of Atherosclerosis. ConclusionsThe association between HRV and mortality risk is modified by RHR levels. Furthermore, low HRV and high RHR have interdependent and synergistic associations with mortality risk.

Association between health-related quality of life and heart rate variability in elderly individuals with cognitive impairment in Korea: cross-sectional study

BackgroundCognitive impairment, a characteristic and prior stage of dementia, is a serious public health concern in Korea a country with rapidly aging population. In a neurovisceral integration model, cognitive ability is connected to emotional and autonomic regulation via an interconnection in the brain, which may be associated with health-related quality of life (HRQoL).MethodsThis study investigated the association between the HRQoL and the autonomic nervous system (ANS) via EuroQoL-5 Dimension (EQ-5D) and heart rate variability (HRV) among 417 patients who visited the Neurology Department in Veterans Health Service Medical Center, Seoul, South Korea.ResultsThe mean age of 275 patients in the cognitive impairment group (CIG) was higher than that of 142 patients in the normal cognition group (NCG) (74.85 years vs. 72.96 years, p < 0.001). In a generalized linear model with a beta coefficient (β), an increase in HRQoL was associated with higher HRV levels was observed only in CIG (CIG: the standard deviation of all NN intervals (SDNN) (ln, ms): β = 0.02, p = 0.007; Total power spectral density (TP) (ln, ms2): β = 0.01, p = 0.007; High frequency (HF) (ln, ms2): β = 0.01, p = 0.015; Low frequency (LF) (ln, ms2): β = 0.01, p = 0.003) (NCG: SDNN (ln, ms): β = 0.01, p = 0.214; TP (ln, ms2): β = 0.01, p = 0.144; HF (ln, ms2): β = 0.00, p = 0.249; LF (ln, ms2): β = 0.01, p = 0.294).ConclusionsWe found a significant association between HRQoL and HRV in Korean elders with cognitive impairment. However, this study is cross-sectional, so we cannot define direct causation. Further studies are needed to support our findings and to elucidate the biological mechanisms underlying these associations, especially in people cognitively impaired.

Intensive Glycemic Therapy in Type 2 Diabetes Patients With Cardiac Autonomic Dysfunction: The ACCORD Trial

ObjectiveTo assess whether the presence of cardiac autonomic dysfunction denoted by low heart rate variability (HRV) modifies the effect of intensive glycemic therapy on outcomes in patients with type 2 diabetes. Patients and MethodsThis study included 7946 participants in the ACCORD (Action to Control Cardiovascular Risk in Diabetes) trial from January 2001 through June 2009. Heart rate variability measures included standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). Abnormal values were defined based on less than the 10th percentile for SDNN and rMSSD. ResultsCompared with standard therapy, intensive therapy was associated with improved primary outcome (composite of cardiovascular events) in the low-HRV group (SDNN: HR, 0.57; 95% CI, 0.39 to 0.84; rMSSD: HR, 0.57; 95% CI, 0.38 to 0.84), but not in the normal-HRV group (SDNN: HR, 0.90; 95% CI, 0.77 to 1.05; rMSSD: HR, 0.90; 95% CI, 0.77 to 1.05). A similar pattern was found for coronary heart disease. Conversely, intensive therapy had a neutral effect on all cause death in the low-HRV group (SDNN: HR, 0.88; 95% CI, 0.54 to 1.41; rMSSD: HR, 0.71; 95% CI, 0.43 to 1.17;), but increase risk of all-cause death in the normal-HRV group (SDNN: HR, 1.21; 95% CI, 1.00 to 1.46; rMSSD: HR, 1.25; 95% CI, 1.03 to 1.51). Intensive therapy induced a greater risk of hypoglycemia in the normal-HRV group than that in the low-HRV group. ConclusionCardiac autonomic dysfunction expressed as low HRV identified subpopulations in ACCORD with more benefits and less harms from intensive therapy.

Influence of 12 weeks of basketball training on college students' heart function.

This study aims to investigate the influence of 12 weeks of basketball training on college students' heart function. The subjects were 30 college male basketball players. Carry out 8-week interval training, monitor the training load and interval time of athletes, and strictly control the heart rate during the interval. Before and after training, we used safe and effective experimental instruments - without any damage to the athletes - to detect the relevant indicators of the athletes' physiological functions; hence we compared and analyzed the various indicators before and after training. The time domain indexes Root Mean Square of Successive Differences (RMSSD), Statistically Determined Spatial Drift (SDSD), percentage of NN50 in the total number of NN intervals (PNN50), and Standard Deviation of all NN intervals for all 5-min segment (SDNN) after training were significantly higher than those before training, and the differences were statistically significant (p<0.05). Average (Avag) and Statistically Determined Allocation Weights (SDAW) after training were significantly higher than those before training, the difference was statistically significant (p<0.05); Asymmetry (Asym) and Tension index (TI) were significantly lower than those before training, the difference was statistically significant (p<0.05), Application Information Index (ApInf) had no significant difference (p>0.05). There was no significant difference in shooting hit rate (p>0.05). The speed of the 8-character dribble in the whole field after training was significantly lower than that before training, and the differences were statistically significant (p<0.05). There was no significant difference in average jump height, maximum jump height, average time in the air, and best jump time in the air after training (p>0.05). For the test of athletes' explosive power, five vertical jumps in situ were selected for testing, and the jump height and time in the air of each vertical jump were counted to calculate the maximum and average values of five vertical jumps. The results showed that there was no significant change in the explosive force of the athletes' lower limbs after training. The reason may be that strength training needs to follow the principles of heavy load, specialization, exercise sequence and reasonable interval. The intermittent training method used during training is not specialized in strength training, and the reasonable interval of strength training was not considered in the training process. Intermittent training can increase the tension of the cardiac vagus nerve of college basketball players, increase the cardiac reserve function and the load that the heart can bear, so that the cardiac function can be improved well. It can improve the cardiopulmonary function and aerobic work ability of college basketball players. It can improve the adjustment ability of the heart, lungs, liver, and other organs of college basketball players. It also can increase the load intensity that the central nerve can bear and improve the function of the central nerve and autonomic nerve. The anti-fatigue ability of athletes can be improved. It can improve the speed quality of college basketball players.

Effect of Objective Daytime Sleepiness on Heart Rate Variability in Patients With Obstructive Sleep Apnea

Excessive daytime sleepiness (EDS) is associated with cardiovascular events in patients with obstructive sleep apnea (OSA). Our study explored the correlation between objective daytime sleepiness assessed with daytime multiple sleep latency tests (MSLT) and heart rate variability (HRV) in OSA patients. The results may provide insight into possible mechanisms underlying increased risk of cardiovascular events in patients with OSA. A retrospective analysis was conducted with the data of 139 patients with OSA and 35 patients with primary snoring. All subjects underwent polysomnography (PSG) and MSLT at West China Hospital between January 2019 and May 2022. We used mean sleep latency (MSL) to measure the severity of EDS and to categorize OSA patients into three groups, severe EDS, light EDS, and non-EDS, with MSL of less than 5 minutes, 5 to 10 minutes, and greater than 10 minutes as the respective defining criteria for classification. A comparison of sleep structure, clinical characteristics, and HRV parameters was performed in order to evaluate the difference between OSA subgroups with varying levels of objective EDS and the primary snoring group. In addition, we also analyzed the correlation between MSL and HRV parameters. Severe EDS patients had higher values of standard deviation of all N-N intervals (SDNN), total spectral power (TOT), and low-frequency power (LF) as compared to non-EDS patients, which was indicative of sympathetic stimulation ( P<0.05). Additionally, high-frequency power (HF) was also higher in severe EDS patients, which indicated decreased parasympathetic drive. A significantly positive correlation was found between MSL and the values of SDNN, TOT, LF, and HF in OSA patients. OSA patients with objective EDS have elevated sympathetic drive and decreased parasympathetic drive. A positive correlation was found between this change in neural activity and the shortening of MSL.

Moderate continuous- and high-intensity interval training elicit comparable cardiovascular effect among middle-aged men regardless of recovery mode

ABSTRACT To assess the effect of active and passive intra-interval recovery modes in time-efficient high-intensity interval training (HIT) on cardiorespiratory fitness, autonomic function, and endothelial function in sedentary middle-aged men. Participants (n = 62; age: 49.5 ± 5.8 y; BMI: 29.7 ± 3.7 kg·m−2) completed the assessments of cardiorespiratory fitness, flow-mediated dilation (FMD) and heart rate variability before being randomly allocated to control (CON; n = 14), moderate intensity continuous training (MICT; n = 15), HIT with passive (P-HIT; n-15), or active recovery (A-HIT; n = 15). Participants performed thrice weekly exercise sessions for 12 weeks. MICT completed 50–60 min of continuous cycling at 60–70% heart rate (HR) maximum. HIT completed 30-s work intervals (∼85% HR) interspaced with 2.5 min of active or passive recovery. All exercise modalities increased oxygen uptake (V̇O2) (MD: ≥ 3.1 ml·kg−1·min−1, 95%CI: 1.5–4.7 ml·kg−1·min−1; P < 0.001), power output (MD: ≥ 26 W, 95%CI: 15–37 W; P < 0.001) and cycle duration (MD: ≥ 62 s, 95%CI: 36–88 s; P < 0.001) at 85% HRM. Significant pre-to-post differences were observed among all exercise groups for FMD (MD: ≥ 3.4%, 95%CI: 0.3–6.5%; P < 0.05), while MICT and P-HIT significantly increased the standard deviation of all NN intervals (SDNN) pre-to-post intervention (MD: ≥ 7 ms, 2–13 ms; P ≤ 0.05). Time-efficient HIT elicits significant improvements in cardiorespiratory fitness, FMD and autonomic modulation following a thrice weekly 12-week exercise intervention among sedentary middle-aged men. Active recovery between successive high-intensity intervals provided no additional benefit among this deconditioned cohort.

Could Heart Rate Variability Serve as a Prognostic Factor in Patients with Pulmonary Hypertension? A Single-center Pilot Study.

Heart rate variability (HRV), which is defined as cyclic changes in sinus rate with time, is used as a measure of cardiac autonomic tone. Our aim was to determine the impact of HRV on short-term prognosis in pulmonary hypertension (PH). We enrolled 64 PH patients and 69 healthy subjects (control group). Patients were evaluated by Holter-ECG, echocardiography, and laboratory tests. 24-h Holter-ECG monitoring was used for HRV. The development of adverse events (right heart failure, hospitalization, syncope, and death) during the 6-month follow-up was evaluated in PH group. PH group (39 ± 16 years, 37.5% males) comprised of 16 patients with idiopathic pulmonary arterial hypertension (PAH) (25%), 36 patients with PAH associated with congenital heart disease (56.3%), 3 PAH associated with connective tissue disease (4.7%), 1 with portopulmonary (1.6%), and 8 chronic thromboembolic PH (12.5%). The time-dependent (standard deviation of all NN intervals for a selected time period [SDNN], standard deviation of the 5-min mean R-R intervals tabulated over an entire day [SDANN], SDNN Index, and Triangular Index) and frequency-dependent HRV indices (low frequency, high-frequency power, and total power,) were significantly reduced in those with PH. Functional class was negatively associated with SDNN, SDANN, SDNN Index, and Triangular Index. Adverse events developed in 25% of the patients during the 6-month follow-up period (200 ± 92 days) (7 patients had right-heart failure, 5 syncope, 12 patients were hospitalized, and 9 had died). All the time and frequency-dependent indices significantly associated with adverse events. Mortality correlated with SDNN (rS = -0.354, P = 0.005), SDANN (rS = -0.368, P = 0.004), SDNN Index (rS = -0.257, P = 0.045), Triangular Index (rS = -0.310, P = 0.014), and VLF (rS = -0.265, P = 0.039). HRV is significantly depressed in patients with PH and is associated with the clinical status. HRV indices might predict clinical deterioration, adverse events, and mortality for 6 months. Non-invasive assessment of HRV through Holter-ECG may be a valuable and practical tool in risk stratification of patients with PH for short-term outcomes.

Impaired heart rate variability in patients with arrhythmogenic cardiomyopathy: A multicenter retrospective study in China

Cardiac sympathetic nerve system (SNS) might play an important role in arrhythmogenesis of arrhythmogenic cardiomyopathy (ACM). This study aims to assess the activity of cardiac SNS in ACM patients by heart rate variability (HRV), and to investigate its predictive value for sustained ventricular tachycardia (sVT). A total of 88 ACM patients and 65 sex- and age- matched healthy participants were enrolled. The time domain measures were used to evaluate the activity of cardiac SNS. An independent cohort with 48 ACM patients was as the validation cohort. ACM patients had lower levels of standard deviation of all NN intervals (SDNN) [118.0 (90.3, 136.8) vs. 152.0 (132.5, 174.5) ms, p < 0.001] compared with healthy participants. Further analysis showed ACM patients with sVT had lower levels of SDNN than those without sVT (105.0 ± 28.1 vs. 131.8 ± 33.1 ms, p < 0.001). Multivariate logistic regression analysis showed SDNN was independently associated with sVT in ACM patients [odds ratio (OR) 0.59, 95% confidence interval (CI) (0.45-0.78), p < 0.001]. Receiver operating characteristics curve demonstrated SDNN had clinical values in predicting sVT in ACM patients [area under the curve (AUC) = 0.73, 95% CI (0.63-0.84), p < 0.001], which was verified in the validation cohort. The present study suggests that HRV is impaired in patients with ACM, and the SDNN level has a moderate value in risk stratification for sVT in ACM patients. In addition, the finding might provide new target for the further management of ACM with integrated traditional Chinese and western medicine.

Heart rate variability in patients with insomnia disorder: a systematic review and meta-analysis.

Though logical inference based on small studies suggests that patients with insomnia have a blunted heart rate variability (HRV), this condition not been clearly shown. This meta-analysis aimed to determine whether or notHRV was impaired in patients withinsomnia. We conducted a comprehensive literature search for studies that examined the association of HRV with insomnia disorder. HRV measures were extracted using the SDNN (time-domain measure, i.e., standard deviation of all NN intervals,) or the HF-norm (frequency-domain measure, i.e., high-frequency power normalized using total power). The effect size estimates of R_equivalent obtained from p values and sample size were synthesized. We identified 17 studies with 921 participants. The pooled R_equivalent was 0.19 with 95% CI of 0.12 and 0.25 (p < 0.001), and there was no significant heterogeneity (I2 = 0.0%, p = 0.809). A p value of 0.075 corresponding to the R_equivalent of 0.19 was obtained, suggesting that blunted HRV was not significant in patients with insomnia disorder. The current evidence did not confirm that HRV was reliably impaired in patients with insomnia disorder. Prospective studies using standard HRV measures are needed to clarify the HRV dynamics in different insomnia subtypes.

Analysis of Heart Rate and Heart Rate Variability Immediately After Continuous Positive Airway Pressure Titration in Patients With Moderate to Severe Obstructive Sleep Apnea

Background and Objectives Recurrent hypoxia, hypercapnia, and arousal during sleep can induce hyperactivity of the sympathetic nervous system (SNS) in patients with obstructive sleep apnea (OSA), which contributes to the development of hypertension and cardiovascular disease. This study was designed to compare changes in heart rate (HR) and heart rate variability (HRV), both of which reflect the activity of the autonomic nervous system (ANS) in OSA patients before and immediately after continuous positive airway pressure (CPAP) titration.Subjects and Method Thirty-five OSA patients (47.8±12.3 years) and 16 healthy subjects (43.2±12.5 years) were enrolled in this study. A night CPAP titration was performed on the OSA patients, and HRV was calculated by RR intervals from the electrocardiogram signals during the total sleep time.Results The mean age of OSA patients was 47.8 years (M:F=34:1), and the control group was 43.3 years (M:F=14:2). The mean AHI of OSA patients was 53.4±31.9, and decreased 17.3±19.4 after CPAP titration, and 4.3±1.6 in the normal controls. During CPAP titration, the mean HR of OSA patients was 68.0±8.9, which was significantly higher than that of the normal controls, 59.5±9.0 (&lt;i&gt;p&lt;/i&gt;=0.003). For HRV, standard deviation of all NN intervals (&lt;i&gt;p&lt;/i&gt;=0.001), root mean square of the successive NN intervals (&lt;i&gt;p&lt;/i&gt;&lt;0.001), and low frequency (LF) (&lt;i&gt;p&lt;/i&gt;=0.006) values were significantly decreased after CPAP titration compared to the baseline. After CPAP titration, LF (&lt;i&gt;p&lt;/i&gt;=0.017) and LF/HF (&lt;i&gt;p&lt;/i&gt;=0.003) values were still significantly higher than those of the normal controls.Conclusion HRV analysis revealed that CPAP titration for one day caused decreased SNS activity but did not induce a balance in ANS when compared to the normal controls.

The Impact Of Varying Blood Flow Restriction Cuff Size On Cardiac Autonomic Modulation In Healthy Males

Blood flow restriction (BFR) training is commonly utilized to stimulate skeletal muscle hypertrophy and assist in strength gains in various populations, ranging from healthy, athletic, clinical, and elderly populations. BFR has the potential to influence the sympathetic and parasympathetic interaction by stimulating acute changes in the vascular endothelium, thereby altering cardiac autonomic modulation (CAM). Heart rate variability (HRV) is a non-invasive way to assess changes in CAM. What is unknown is the influence BFR may have on CAM due to the changes in venous and arterial pressure. PURPOSE: To determine if different BFR cuff sizes and materials alter CAM when assessed in healthy young men. METHODS: Twenty healthy males (n = 20 males, Age 25 ± 5 years, HR 66 + 11.3 bpm, SBP 125.1 + 13.4 mmHg, DBP 75.1 + 12.5 mmHg) completed a randomized, counter-balanced, cross-over design that utilized a widely-employed wide rigid (WR) cuff, along with the largest (NE) and manufacturer recommended sizes (NER) of a novel narrow-elastic cuff. HRV was measured in the supine position at baseline and amidst all three BFR cuffs at 80% arterial occlusion pressure using an elastic belt and Bluetooth monitor (Polar H7). CardioMood software was used to process HRV variables high frequency (HF), low frequency (LF), total power (TP) was assessed for frequency domain, and standard deviation of all NN intervals (SDNN) and the square root of the mean of the squares of successive R-R interval differences (RMSSD) for the time domain. The data were analyzed with SPSS using a repeated-measures ANOVA to examine differences between dependent variables, including selected time and frequency domain HRV indices. RESULTS: HRV frequency domain variables LF, HF, LF/HF, and TP, and time domain, SDNN, and RMSSD variables were not significantly altered with WR, NE, or NER cuff protocols when compared to baseline. There were no significant differences between cuff protocols. CONCLUSION: There were no changes in CAM with BFR cuff protocols in healthy young men. The lack of changes indicates that changes in the venous and arterial pressure ratio due to BFR were not great enough to offset the sympathetic and parasympathetic systems.

Cross-sectional and longitudinal associations of styrene and ethylbenzene exposure with heart rate variability alternation among urban adult population in China

Styrene and ethylbenzene (S/EB) are the monomers of polystyrene (PS) and polyethylene (PE), respectively, and have been identified as significant hazardous air pollutants by the U.S. Environmental Protection Agency. However, the adverse effects of S/EB on human health, especially cardiovascular health, have not been well established. Urinary biomarker of S/EB exposure and heart rate variability (HRV) were measured in urban adults from the Wuhan-Zhuhai cohort and were repeated after 3-year and 6-year follow-ups. Linear mixed models were used to estimate associations of S/EB exposure biomarker with HRV and longitudinal additional annual change of HRV. The mediating role of transforming growth factor (TGF)-β1 was tested by using mediation analysis. A total of 2842 general adults were included at baseline analysis, and 4748 observations were included in the repeated measurement study. In the cross-sectional analysis, each 1% increment in urinary S/EB exposure biomarker was significantly associated with a 0.106 % (95 % CI: −0.160, −0.052), 0.109 % (−0.169, −0.049), 0.099 % (−0.145, −0.053), 0.040 % (−0.060, −0.020), and 0.031 % (−0.054, −0.007) decrement in low frequency (LF), high frequency (HF), total power (TP), standard deviation of all normal-to-normal intervals (SDNN), and square root of the mean squared difference between adjacent normal-to-normal interval, respectively. Smoking status modified the relationships of urinary S/EB exposure biomarker with TP and SDNN. TGF-β1 mediated 3.09–5.16 % of the association between urinary S/EB biomarker and lower HRV. The follow-up analyses detected a negative association between urinary S/EB exposure biomarker and the additional annual change of LF (β: −0.016; 95 % CI: −0.028, −0.004), HF (−0.014; −0.026, −0.001), and TP (−0.011; −0.021, −0.001). Our findings demonstrated that S/EB exposure was associated with HRV reduction among the general urban adults and the TGF-β pathway may play a part of the mediating role in this association.

Differences in the Impact of Heart Rate Variability on the Surgical Approach in Patients With Early Cervical Cancer: Laparoscopic versus Open Surgery.

BackgroundEvidence suggests that the risk of recurrence and death in patients with early cervical cancer (ECC) undergoing minimally invasive surgery is significantly higher than that in patients undergoing open surgery. However, the mechanisms underlying such a difference remain unclear. Heart rate variability (HRV) represents autonomic nerve activity, which is related to tumorgenesis and can be used as a prognostic indicator for various cancers. The main purpose of this study was to explore the difference in the effects of laparoscopic and open surgery on HRV in ECC patients.MethodsA total of 68 ECC (FIGO IA1 with lymphovascular space invasion -IIA2) patients undergoing radical hysterectomy for the first time (84% open group vs. 16% laparoscopic group) were included. A single-lead micro-ECG recorder was used to collect 5 min electrocardiograms 1 day before the operation and 3 days after the operation, and then HRV time domain and frequency domain indices were analyzed, including mean heart rate (MeanHR), maximum heart rate (MaxHR), minimum heart rate (MinHR), the standard deviation of all normal-to-normal intervals (SDNN), the root mean square of successive interval differences (RMSSD), very low-frequency power (VLF), low-frequency power (LF), high-frequency power (HF), total power (TP), and the ratio of LF to HF (LF/HF).ResultsHeart rate (i.e., MeanHR, MaxHR, and MinHR) were significantly higher, and HRV (i.e., SDNN, RMSSD, LF, HF, and TP) were significantly lower after the operation than before the operation in both the laparoscopic and open groups (P < 0.05). The postoperative reduction in RMSSD and HF was significantly higher in the laparoscopic group than in the open group (P < 0.05).ConclusionsThese data suggest that radical hysterectomy can lead to increased heart rate and decreased HRV in patients with ECC, which can negatively affect cardiac autonomic regulation. Compared with open surgery, laparoscopic surgery has a greater negative impact on the HRV of ECC patients.

Risk Factors and Heart Rate Variability Associated with Left Ventricular Enlargement in Patients with Frequent Premature Ventricular Contractions

Introduction: Premature ventricular contractions (PVCs) were now well recognized to carry the risk of inducing left ventricular (LV) enlargement and were closely related to the cardiac autonomic nervous activity quantified by heart rate variability (HRV) analysis. However, the relationship between LV enlargement and HRV in patients with frequent PVCs is still unclear. This study aimed to investigate the risk factors and HRV for LV enlargement in patients with frequent PVCs. Methods: Patients with frequent PVCs (n = 571), whose PVC burden counts >10,000/24 h or PVC burden >10%, were recruited. Patients were divided into LV enlargement group (n = 161), defined as female left ventricular end-diastolic diameter (LVEDD) >49.8 mm or male LVEDD >54.2 mm, and LV normal group (n = 410). Two groups were compared on their clinical, electrocardiographic, and HRV parameters. Logistic regression analysis was used to predict the risk factors of LV enlargement in patients with frequent PVCs. The parameters of echocardiography, Holter monitoring, and HRV were collected after ablation. Results: There were significant differences between the patients with left enlargement and with normal LV structure, in terms of sex, left ventricular ejection fraction (LVEF), level of N-terminal pro-brain natriuretic peptide (NT-proBNP), 24-h PVC burden, with nonsustained ventricular tachycardia, multifocal PVCs, QRS duration of PVC, and values of very low-frequency power of HRV parameter (all p < 0.05). Multivariate analysis showed that female gender (odds ratio [OR] = 2.753, p < 0.001), increased NT-proBNP (OR = 1.011, p = 0.022), increased LVEF (OR = 0.292, p < 0.001), increased 24-h PVC burden (OR = 1.594, p < 0.001), increased standard deviation of all NN intervals (SDNN) (OR = 1.100, p = 0.003), increased the proportion of consecutive NN intervals that differ by more than 50 ms (pNN50) (OR = 0.844, p = 0.026) were predictors for LV enlargement in patients with frequent PVCs. 84.4% (54/64) of patients with LV enlargement at baseline had normalized their LV structure after ablation. The values of SDNN, standard deviation of the averages of NN intervals in all 5-min segments, the square root of the mean of the sum of the squares of differences between adjacent NN intervals, pNN50, low-frequency power (LF), LF/high-frequency power ratio of patients were significantly decreased after ablation (all p < 0.05). Conclusion: Female gender, increased level of NT-proBNP, lower LVEF, higher PVC burden, increased sympathetic parameters SDNN, and reduced parasympathetic parameters pNN50 were the independent risk factors of LV enlargement in patients with frequent PVCs. LV enlargement induced by PVCs can be reversible after PVC elimination by ablation. The activities of sympathetic and parasympathetic were reduced after ablation.

Effects of Acute Exercise on Cardiac Autonomic Response and Recovery in Non-Dialysis Chronic Kidney Disease Patients

ABSTRACT Purpose: Heart rate variability (HRV) has gained acceptance as a key marker of cardiovascular health. We compared HRV responses after continuous moderate-intensity exercise (CMIE) and high-intensity interval exercise (HIIE) matched for intensity and duration in individuals with midspectrum chronic kidney disease (CKD). Methods: Twenty men and women (age 62.0 ± 10 yrs.) diagnosed with CKD stages G3a and G3b participated in a 2 (condition) x 4 (time point) repeated cross-over measures design study. HRV time-domain indices were based on the standard deviation of all NN intervals (SDNN) and the square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD) and frequency domain. High-frequency (HF), low-frequency (LF), total power (TP) were examined. CMIE consisted of treadmill walking for 30 minutes at a 2% incline and speed corresponding to 60%–65% of reserve volume of oxygen (VO2R). HIIE included five intervals of 3 minutes at 90% of VO2R and 2 minutes at 20% VO2R intervals. Conditions were designed to be of the same average intensity (60% to 65% of VO2R) and caloric expenditure (~144 kcal). Results: Immediately following exercise SDNN, RMSSD, HF, LF, and TP were significantly lower compared to before exercise (p <.05). HRV responses were not different between conditions and conditions X time (p >.05). Conclusions: Thirty minutes of either CMIE or HIIE decreased HRV indices, pointing to an autonomic imbalance favoring vagal mediation. HRV’s responses regarding HIIE were no different from CMIE, therefore, from an autonomic function point of view this similarity may be useful for CKD exercise prescription and programming.

Association of heart rate variability with progression of retinopathy among adults with type 2 diabetes.

AimWe evaluated the associations of heart rate variability (HRV) with incident vision‐threatening retinopathy and retinopathy progression among adults with type 2 diabetes.MethodsParticipants recruited to the ACCORD (Action to Control Cardiovascular Risk in Diabetes) study with HRV measures at baseline were analysed. HRV measures included standard deviation of all normal‐to‐normal intervals (SDNN) and root mean square of successive differences between normal‐to‐normal intervals (rMSSD). Low SDNN was defined as SDNN <8.2 ms; low rMSSD as rMSSD <8.0 ms. We used multivariable adjusted Cox proportional hazards and modified Poisson regression models to generate risk estimates for incident vision‐threatening retinopathy and retinopathy progression, respectively.ResultsA total of 5810 participants without incident vision‐threatening retinopathy at baseline (mean age 62 years, 40.5% women, 63.5% White) were included. Over a median of 4.7 years, 280 incident vision‐threatening retinopathy cases requiring treatment occurred. Low HRV (vs. normal HRV) was associated with higher risk of incident vision‐threatening retinopathy (adjusted hazard ratio 1.32 [95%CI 1.03–1.71] and 1.14 [95%CI 1.01–1.28] for low SDNN and rMSSD, respectively). In the subset of 2184 participants with complete eye examinations at baseline and 4 years, 191 experienced retinopathy progression, and low HRV (vs. normal HRV) was associated with a higher risk of retinopathy progression (adjusted relative risks 1.36 [95%CI 1.01–1.83] and 1.36 [95%CI 1.01–1.84] for low SDNN and rMSSD, respectively).ConclusionsCardiac autonomic neuropathy, as assessed by low HRV, was independently associated with increased risks of incident vision‐threatening retinopathy and overall retinopathy progression in a large cohort of adults with type 2 diabetes.

Stimulation method and individual health index study for real-time cardiovascular and autonomic nervous system reactivity analysis using PPG signal

Homeostasis in a healthy heart is maintained through the interaction of the autonomic nervous system (ANS) with the cardiovascular system (CS) in response to changes in the environment. However, the problem of the ANS and CS reactivity caused by aging and chronic disease increases the risk of fatal heart disease and negatively affects an individual's health. Therefore, we propose a method and heart rate variability (HRV) index that can continuously monitor the reactivity of ANS and CS in daily life. To analyze real-time changes in ANS and CS of a total of 22 subjects, HRV was induced by changing the posture from a sitting position to a standing position while measuring photoplethysmogram. As a result, it was confirmed that the HRV changed from 0.75 ± 0.11 s to 0.65 ± 0.10 s (P < 0.05) had a change value similar to the method used in clinical. Physiological ANS activity can be confirmed through the standard deviation 1 (SD1) and 2, and ANS activity reflected in CS can be obtained through the standard deviation of all NN intervals (SDNN) and the root mean square of successive heartbeat interval differences (RMSSD) analysis. As a result of analyzing the two values, the 5-minute average SD1/RMSSD is identified as an indicator that can confirm the function of the baroreceptors indicative of CS reactivity. In addition, we propose a real-time SDNN as an index that can check the term of the activated ANS in response to a sudden CS change.

Assessment of Exhaustive Exercise under Internet of Things Exercise Monitoring System and Mechanism Analysis of Cardiovascular Endothelial Cell Apoptosis Induced by Oxidative Stress

To investigate the effect of high-intensity exhaustive exercise on body and the molecular mechanism of oxidative stress regulating apoptosis of cardiovascular endothelial cells (CVECs), 70 college students who took an aerobics course were recruited as the research subjects, all of which were divided into the high-intensity group (35 students) and the moderate-intensity group (35 students). The Internet of Things- (IoT-) based human exercise information monitoring system was employed to collect the electrocardiogram, serum indexes, and oxidative stress indexes of the two groups of subjects after exercise. Moreover, 30 clean male SD rats were divided into exhaustive exercise group ( n = 10 ), routine exercise group ( n = 10 ), and blank control group ( n = 10 ) using treadmill exercise as stress source, and various physiological indexes of the three groups were compared. In human experiments, the time-domain indexes of heart rate variability (HRV), 50 ms in the total number of sinus heartbeats (PNN50), the standard deviation of all NN intervals (SDNN), standard deviation of mean NN interval (SDANN), standard deviation of difference between adjacent NN intervals (SDSD), root mean square (RMSSD) in the high intensity group were lower than those in the moderate intensity group ( P &lt; 0.05 ). The levels of T-sensitive troponin I (Tnl-ultra), cortisol (COR), high-sensitive troponin T (TnT-hs), high-sensitive C-reactive protein (hs-CRP), and human heart-type fatty acid binding protein (HUMAN H-FABP) in high intensity group were higher than those in moderate intensity group ( P &lt; 0.05 ). Experiments on animals found that SOD content and mRNA expression of fork-head box 03A (FOX03A) and silencing-information regulator 1 (Sirtl) in serum of rats in exhaustion exercise group were lower than those in the routine exercise group and blank control group, while lactate dehydrogenase (LDH) and malondialdehyde (MDA) contents were opposite ( P &lt; 0.05 ). In short, strenuous exercise made the body in the state of acute stress, leading to the disturbance of cardiac autonomic nervous function and sympathetic nervous function, and increasing the risk of malignant arrhythmia. Oxidative stress induced by exhaustive exercise may promote the apoptosis of CVECs by reducing the expression of Sirtl and FOX03A and locating FOX03A to the nucleus.

Relationship Between Cognitive Appraisal of Control and Cardiac Vagal Regulation During an Unsupported Ski Crossing of Greenland.

PurposeThe aim of the present study was to investigate the relationships between Perceived Control (PC) and Heart rate variability (HRV) during a 27-day expedition, during which an unsupported crossing was made from the west coast to the east coast of Greenland (across the Ice Sheet); and that therefore a high PC represents a favourable factor for recovery and stress management.MethodsFour subjects participated in the study. PC was measured on alternated days in the evening at the end of the day, using the Pearlin Mastery Scale; and the next day, upon waking, heart rate using a wrist heart rate monitor and a chest strap. Together with the PC, the perceived effort was measured through the CR-100 Borg scale and each subject was asked to indicate the most emotionally significant event of the day.Time and frequency domain indices for heart rate variability were calculated.ResultsSeveral correlations were observed between PC and HRV indices. In particular two indices in the time domain, standard deviation of all NN intervals (SDNN) (rrm = 0.51) and root mean square of successive (RMSSD) (rrm = 0.46), showed a significant and strong positive correlation.ConclusionThe existence of a positive correlation between PC and cardiac vagal regulation is of great interest to individuals immerged into extreme situations, because it can affect performance or prevents maladaptive states or injuries. To improve stress management, it could be convenient for members of extreme expeditions to adopt forms of cognitive training that modify their cognitive appraisal in order to raise their perception of control.

Cardiac autonomic neuropathy and risk of incident heart failure among adults with type 2 diabetes.

Community-based data on the association between cardiac autonomic neuropathy (CAN) and incident heart failure (HF) in type 2 diabetes are limited. We evaluated the association of CAN with incident HF in adults with type 2 diabetes. This analysis included participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study without HF at baseline. CAN was assessed by electrocardiogram-based measures of heart rate variability (HRV) and QT interval index (QTI). HRV was measured using standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). CAN was defined using composite measures of the lowest quartile of SDNN and highest quartiles of QTI and heart rate. Multivariable Cox regression models were used to generate adjusted hazard ratios (aHR) for HF in relation to various CAN measures. A total of 7160 participants (mean age 62.3 [standard deviation 6.4] years, 40.8% women, 61.9% white) were included. Over a median follow-up of 4.9 years (interquartile range 4.0-5.7), 222 participants developed incident HF. After multivariable adjustment for relevant confounders, lower HRV as assessed by SDNN was associated with a higher risk of HF (aHR for the lowest vs highest quartile of SDNN: 1.70, 95% confidence interval [CI] 1.14-2.54). Participants with CAN (defined as lowest quartile of SDNN and highest quartiles of QTI and heart rate) had a 2.7-fold greater risk of HF (aHR 2.65, 95% CI 1.57-4.48). In a large cohort of adults with type 2 diabetes, CAN was independently associated with higher risk of incident HF.