Standard Deviation Of NN Intervals Research Articles

Telemetry-derived heart rate variability responses to a physical stressor.

To assess the validity and reliability of telemetry-derived HRV responses to an orthostatic challenge. Twenty healthy adults (26+5years, 45% male) were tested on three separate mornings. Following 20-min supine rest, R-R intervals were recorded using a telemetric device during three conditions: BASE, TILT and RECOVERY. ECG was simultaneously used on 1day for validity comparison. Measures of HRV included the following: standard deviation of normal-to-normal intervals (SDNN), the root-mean-square of successive differences (RMSSD) and the low-frequency (LF) and high-frequency (HF) spectral power. For all parameters, there was excellent agreement between devices for BASE (r=0·96-0·99), TILT (r=0·89-1·00) and RECOVERY (r=0·96-1·00). For the telemetric device, between-day intraclass coefficient values for RMSDD, SDNN and HF were all above the 0·75 criterion for each condition, indicating excellent between-day reliability. For each condition, the reliability coefficient, expressed as a percentage of the mean (RC%), was marginally lower (greater reliability) for RMSDD (RC% 11-13) and SDNN (RC% 10-12) compared to HF (RC% 12-17). However, SDNN did not significantly respond to the orthostatic challenge. Telemetric HRV, particularly RMSDD and HF, can be used to provide a sensitive, valid and reliable assessment of autonomic control of heart rate.

Evaluation of heart rate variability in patients with coronary artery ectasia and coronary artery disease.

The present study compared heart rate variability (HRV) parameters in patients with coronary artery ectasia (CAE) and coronary artery disease (CAD). The study population consisted of 60 consecutive patients with CAE (14 women; mean age 51.63±7.44 years), 60 consecutive patients with CA (15 women; mean age 53.67±9.31 years), and 59 healthy individuals (13 women; mean age 52.85±8.19 years). Electrocardiograms, 24-hour Holter analyses, and routine biochemical tests were performed, and clinical characteristics were evaluated. Coronary angiography images were analyzed. Time-domain HRV parameters, including the standard deviation (SD) of normal-to-normal intervals (SDNN) and the root mean square of difference in successive normal-to-normal intervals (RMSSD) were evaluated, as were frequency-domain HRV parameters including low-frequency (LF), very low-frequency (VLF), high-frequency (HF), the proportion derived by dividing low- and high-frequency (LF/HF), and total power (TP). SDNN was lower in both the CAE and CAD groups, compared to the healthy group (140.85±44.21, 96.51±31.28, and 181.05±48.67, respectively). A significant difference in RMSSD values among the groups was determined (p=0.004). Significantly decreased VLF and HF values were found in the CAE group, compared with the healthy group (VLF p<0.001; HF, p=0.007). TP, VLF, and HF values were significantly lower (p<0.001, p<0.001, and p<0.001, respectively), but LF and LF/HF values were significantly higher (p<0.001 for both) in the CAD group than in the healthy group. TP values were significantly higher (p<0.001), and LF and LF/HF values were lower in the CAE group, compared with the CAD group (p<0.001 for both). A decrease in vagal modulation or an increase in sympathetic activity of cardiac function, assessed by HRV analysis, is worse in patients with CAD than in patients with CAE.

EVALUATION OF AUTONOMIC DYSFUNCTION BY HEART RATE VARIABILITY ANALYSIS IN TYPE 2 DIABETES MELLITUS

ABSTRACTObjective: Cardiac autonomic neuropathy (CAN) is a severe and common, yet highly underdiagnosed, complication of Type 2 diabetes mellitus(T2DM). Subclinical CAN may have reduced heart rate variability (HRV) but normal Ewing battery test. This study was performed to evaluate theimportance of 5 minutes HRV for the detection of autonomic dysfunction in T2DM without (CAN-T2DM).Methods: This cross-sectional observational study was conducted at the Department of Physiology, Bangabandhu Sheikh Mujib Medical University(BSMMU) on 30 recently diagnosed T2DM (RT2DM) and 54 long-term CAN-male T2DM patients (LT2DM), aged 45-55 years, from the EndocrinologyOut Patient Department of BSMMU, Dhaka. 30 age and body mass index matched apparently healthy male subjects were control. Ewing battery testwas used to rule out CAN positive T2DM. HRV data were recorded by a polyrite-D and analyzed by software. HRV was assessed by time domainmethod. For statistical analysis, ANOVA and unpaired t-test were used.Results: Mean RR, standard deviation of NN intervals (SDNN) (p&lt;0.05), and root mean square of the successive differences (RMSSD) were significantly(p&lt;0.001) lower, and mean HR and SDNN/RMSSD were (p&lt;0.001) significantly higher in LT2DM compared to RT2DM and control. In addition, SDNNwas also significantly (p&lt;0.05) lower in RT2DM than that of control.Conclusions: Results conclude that autonomic dysfunction may occur in both LT2DM and RT2DM patients without neuropathy and 5 minutes HRVtest is an important tool for detecting subclinical CAN.Keywords: Type 2 diabetes mellitus, Cardiac autonomic neuropathy, Heart rate variability.

The results of rehabilitation of the patients presenting with arterial hypertension: the types of adaptation, the vegetative status, and intracardial hemodynamics

The objective the present work was to study the changes of the types of adaptation in the patients presenting with arterial hypertension under the influence of the spa and health resort-based rehabilitative treatment. The study included 50 patients with essential hypertension at the age from 54.0 to 62.0 (mean 58.0) years given a course of the spa and health resort-based rehabilitative treatment. All the patients underwent electrocardiographic and echocardiographic examination for the assessment of the systolic and diastolic left ventricular functions. Cardiointervalography with the use of the ORTO Expert diagnostic system was performed in the patients at rest and during the active orthostatic test (AOT); the types of the adaptation were evaluated. The patients were divided into 2 groups depending on the results of repeated AOT obtained after rehabilitation. Group 1 was comprised of the patients showing the improvement of adaptation (n=24), group 2 consisted of the patients in whom the level of adaptation remained unaltered (n=26). The structural characteristics of echocardiography estimated in both groups were not significantly different. The number of patients in group 1 showing the satisfactory level of adaptation intensity in the absence of its failures increased significantly. In group 2, a significant decrease of the following AOT parameters was documented: the tension index of the regulatory system (p=0.02), the standard deviation of NN-intervals (SDNN) (p=0.03), and root mean square of successive differences (RMSSD) (p=0.02). The multiple logistic regression analysis showed that the factors associated with the positive effect of rehabilitation were the normal and low degree of regulatory system tension (p=0.01) and the initially adequate or reduced response in the orthostatic test (p=0.04). The improvement of rehabilitation of the adaptive capacity was documented in as many as 48% of the patients who had undergone the spa and health resort-based rehabilitative treatment. The absence of positive dynamics or deterioration of adaptation were associated with the increase of the sympathetic activity at rest and in response to the AOT. The beneficial effect of rehabilitation was observed in the patients with the initially normal or low tension of regulatory systems and with the adequate or reduced baseline response in AOT.

Heart Rate Variability as a Predictor of Death in Burn Patients

Heart rate variability (HRV), a noninvasive technique used to quantify fluctuations in the interval between normal heart beats (NN), is a predictor of mortality in some patient groups. The aim of this study was to assess HRV in burn trauma patients as a predictor of mortality. The authors prospectively performed 24-hour Holter monitoring on burn patients and collected demographic information, burn injury details, and in-hospital clinical events. Analysis of HRV in the time and frequency domains was performed. A total of 40 burn patients with a mean age of 44 ± 15 years were enrolled. Mean %TBSA burn was 27 ± 22% for the overall population and was significantly higher in those who died compared with those who survived (55 ± 23% vs 19 ± 13%; P < .0001). There was a statistically significant inverse linear correlation between SD of NN intervals and %TBSA (r = -.337, R = 0.113, 95% CI = -0.587 to -0.028, two-tailed P = .034), as well as with ultra low frequency power and %TBSA burn (r = -0.351, R = 0.123, 95% CI = -0.152 to -0.009; P = .027). The receiver-operator characteristic showed the area under the curve for %TBSA as a predictor of death was 0.82 (P < .001), for SDANN was 0.94 (P < .0001), and for ultra low frequency power was 0.96 (P < .0001). Deranged HRV in the early postburn period is a strong predictor of death.

Influences of improving sleep on heart rate variability and cardiac function among adult chronic heart failure patients

Objective To explore the influences of improving sleep on heart rate variability (HRV) and cardiac function of adult chronic heart failure patients. Methods We selected 38 adult chronic heart failure (CHF) patients with insomnia from January 2012 to January 2013 from the Number One Hospital of Zhangjiakou as control group, and 38 patients from February 2013 to January 2014 as observation group. Patients of two groups were treated with conventional medicine treatment about CHF and routine care, and the patients of observation group received nursing care to improve patients′ sleep quality based on routine care. Standard deviation of NN intervals (SDNN), SDANN, rMSSD, pNN50, the high frequency (HF) and low frequency (LF) and other HRV indexes, LVEF and patients′ satisfaction with effectiveness of medical treatment and nursing between two groups were analyzed. Results After 4 weeks nursing, the rate of patients with insomnia in the observation group was 28.95% and 55.26% in the control group (χ2=5.398, P 0.05). Conclusions Improving CHF patients′ sleep quality can improve HRV and LVEF effectively. Improving sleep is in favor of improving heart function because the HRV is related to heart function. Key words: Adult; Chronic heart failure; Cardiac function; Sleep improving; Heart rate variability; Patients′ satisfaction

Pre-Transplant Autonomic Nervous System Malfunction Is a Powerful Predictor for Survival after Allogeneic Hematopoietic Cell Transplantation

Background: Autonomic nerve function can be affected by various factors such as patient activity of daily living, disease status, treatment history and/or comorbidity. Indeed, autonomic nervous system dysfunction, as indexed by heart rate variability (HRV), has shown prognostic value for various disease outcomes, but its influence on outcomes following allogeneic hematopoietic cell transplantation (allo-HCT) is unclear. We therefore conducted a prospective observational study to determine the impact of autonomic nervous system dysfunction on outcomes following allo-HCT.Methods: From July 2011 to July 2013, we prospectively registered patients who had received allo-HCT in our institute. We also applied well-established examination of HRV as a surrogate maker of the autonomic nervous system. HRV data were collected from 24-hour ambulatory ECG recordings within 28 days of the starting day of the conditioning regimen for allo-HCT. Obtained data were analyzed with RR data analysis software (MemCalc/CHIRAM version 3, GMS Co., LTD., Tokyo, Japan). The following parameters were employed as markers of HRV: standard deviation of NN interval (SDNN) and the squares of the differences between adjacent normal-to-normal RR intervals (r-MSSD) in time domain analysis, and low-frequency (LF) and high-frequency (HF) power in frequency domain analysis. Δ Akaike's information criterion (Δ AIC) was used to compare the HRV components-added model to the basic model by the Pre-transplantation Assessment of Mortality (PAM) score, HCT-specific comorbidity index (HCT-CI), or disease risk index (DRI) in a Cox proportional hazards model.Results: We registered 112 consecutive allo-HCTs (103 patients) who agreed to participate in this study. The median age of the patients was 45.5 years (range: 18-66) and the median follow-up period for survivors (76 patients) was 961 days (range: 159-1654). Diagnoses included acute myeloid leukemia (n=55, 49%), acute lymphoid leukemia/lymphoblastic lymphoma (n=13, 12%), mixed phenotype acute leukemia (n=3, 3%), myelodysplastic syndrome (n=15, 13%), adult T cell leukemia/lymphoma (n=7, 6%), aggressive lymphomas (n=6, 5%), indolent lymphoma/chronic lymphoid leukemia (n=3, 3%), chronic myeloid leukemia/other myeloproliferative neoplasms (n=5, 4%), aplastic anemia (n=2, 2%), and others (n=3, 3%). Stem cell sources consisted of HLA-matched related donors for 18 transplants (16%), mismatched related donors for 24 transplants (22%), matched unrelated donors for 32 transplants (29%), mismatched unrelated donors for 8 transplants (7%), and cord blood for 30 transplants (27%). Myeloablative conditioning was employed for 84 transplants (75%).Median value of LF, HF, SDNN, and r-MSSD was 409 msec2 (range: 27-1279), 103 msec2 (range: 5-1309), 122 msec (range: 48-231), and 20 msec (range: 4-95), respectively.From univariate analysis, the reduction of LF, HF, SDNN, or r-MSSD was significantly associated with decreased probability of OS (hazard ratio (HR): 0.7 for LF per 100 msec2 (p<0001), 0.5 for HF per 100 msec2 (p=0.001), 0.2 for SDNN per 100 msec (p=0.004), and 0.6 for r-MSSD per 10 msec(p=0.01), respectively). Of these four HRV components, the LF-added model for PAM, HCT-CI, and DRI had the highest values of Δ AIC (16.5, 22.2 and 11.4, respectively). From the analysis with stratification into four LF groups divided equally by the number of transplants (n=28), two-year OS was 92.9, 84.5, 59.7, and 33.2%, respectively (p <0.0001). LF solely represented a better discriminating variable for the prediction of survival. Additionally, from bivariate analysis for OS on each LF-added model to PAM, HCT-CI, or DRI, decreased LF was found to be an independent predictor for lower OS (adjusted HR for LF per 100 msec2: 0.7 (p=0.0003), 0.7 (p<0.0001), or 0.7 (p=0.001), respectively).Conclusions: Pre-transplant autonomic nervous system dysfunction is a powerful predictor of survival likely because it reflects the comprehensive physiological or pathological status of the patient. Of note, LF was a powerful predictor for survival and statistically independent from well-known prognostic indexes or scoring systems such as PAM, HCT-CI, and DRI. DisclosuresNakane:Otsuka: Honoraria. Nakamae:Otsuka: Other: My spouse receives research funding from Otsuka; Kyowa Kirin: Other: My spouse receives research funding from Kyowa Kirin. Nishimoto:Otsuka: Honoraria. Hino:Celgene: Honoraria. Nakamae:Otsuka: Honoraria, Research Funding; Kyowa Kirin: Honoraria, Research Funding.

Manipulation of heart rate variability can modify response to anger-inducing stimuli

ABSTRACTResearch suggests that heart rate variability (HRV) is a physiological indicator of the flexibility of the autonomic nervous system and can provide an objective measure of an individual’s ability to appropriately match emotional responses to environmental demands. The present study investigated whether angry response to emotional stimuli was related to HRV, and whether manipulation of HRV using biofeedback could change the anger response in a healthy adult population. Fifty-eight participants received HRV biofeedback (n = 29) or an active control condition (n = 29). HRV measures included standard deviation of normal-to-normal intervals (SDNN), low-frequency (LF) and high-frequency (HF) power, and was recorded across three sessions: baseline, training, and anger induction. The anger induction procedure resulted in increased subjective experience of anger, as well as physiological changes. The biofeedback group had higher HRV than active controls both during the training session (SDNN and LF HRV) and during anger induction (LF HRV). HRV during anger induction was significantly associated with self-reported emotional response for participants receiving biofeedback but not for active controls. Results provide support for HRV as an index of emotion regulation, specifically anger. Further research is needed to determine whether long-term HRV biofeedback can have a lasting effect on managing anger.

Exposure to sub-chronic and long-term particulate air pollution and heart rate variability in an elderly cohort: the Normative Aging Study.

BackgroundShort-term particulate air pollution exposure is associated with reduced heart rate variability (HRV), a risk factor for cardiovascular morbidity and mortality, in many studies. Associations with sub-chronic or long-term exposures, however, have been sparsely investigated. We evaluated the effect of fine particulate matter (PM2.5) and black carbon (BC) exposures on HRV in an elderly cohort: the Normative Aging Study.MethodsWe measured power in high frequency (HF) and low frequency (LF), standard deviation of normal-to-normal intervals (SDNN), and the LF:HF ratio among participants from the Greater Boston area. Residential BC exposures for 540 men (1161 study visits, 2000–2011) were estimated using a spatio-temporal land use regression model, and residential PM2.5 exposures for 475 men (992 visits, 2003–2011) were modeled using a hybrid satellite based and land-use model. We evaluated associations between moving averages of sub-chronic (3–84 day) and long-term (1 year) pollutant exposure estimates and HRV parameters using linear mixed models.ResultsOne-standard deviation increases in sub-chronic, but not long-term, BC were associated with reduced HF, LF, and SDNN and an increased LF:HF ratio (e.g., 28 day BC: −2.3 % HF [95 % CI:−4.6, −0.02]). Sub-chronic and long-term PM2.5 showed evidence of relations to an increased LF and LF:HF ratio (e.g., 1 year PM: 21.0 % LF:HF [8.6, 34.8]), but not to HF or SDNN, though the effect estimates were very imprecise and mostly spanned the null.ConclusionsWe observed some evidence of a relation between longer-term BC and PM2.5 exposures and changes in HRV in an elderly cohort. While previous studies focused on short-term air pollution exposures, our results suggest that longer-term exposures may influence cardiac autonomic function.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-015-0074-z) contains supplementary material, which is available to authorized users.

Impact of heart rate variability on C-reactive protein concentrations in Japanese adult nonsmokers: The Toon Health Study

ObjectiveLower heart rate variability (HRV) is associated with the inflammation that is linked with the progression of atherosclerosis. We examined this association, taking insulin sensitivity into consideration, as it is related to both HRV and inflammation. MethodsSubjects were 1728 individuals ages 30–79 years who did not smoke between 2009 and 2012. C-reactive protein (CRP) concentrations and white blood cell (WBC) counts were assessed as markers of inflammation. The homeostasis model assessment index for insulin resistance (HOMA-IR) and Gutt's insulin sensitivity index (ISI) were calculated based on fasting and 2h-post-load glucose and insulin concentrations in a 75-g oral glucose tolerance test. Pulse was recorded for 5 min, and time-domain HRV indices of standard deviation of NN intervals (SDNN) and root mean square of successive differences (RMSSD) were calculated. Power spectral analysis provided frequency domain measures of HRV: high frequency (HF) power, low frequency (LF) power and LF/HF. ResultsSex and age-adjusted logistic models presented quartiles of SDNN, RMSSD, LF, and HF significantly associated with the highest quartile of CRP or WBC. After adjustment for body mass index and ISI, the associations were attenuated for WBC; however, even after further adjustment for several variables, SDNN, RMSSD, LF, and HF remained significantly associated with elevated CRP concentrations. When results were stratified by weight, the associations appeared more evident among non-overweight individuals. ConclusionLowered HRV, primarily due to parasympathetic dysfunction, was associated with elevated inflammation, independent of weight, insulin sensitivity, and other related factors.

Developing new predictive alarms based on ECG metrics for bradyasystolic cardiac arrest

We investigated 17 metrics derived from four leads of electrocardiographic (ECG) signals from hospital patient monitors to develop new ECG alarms for predicting adult bradyasystolic cardiac arrest events.A retrospective case-control study was designed to analyze 17 ECG metrics from 27 adult bradyasystolic and 304 control patients. The 17 metrics consisted of PR interval (PR), P-wave duration (Pdur), QRS duration (QRSdur), RR interval (RR), QT interval (QT), estimate of serum K + using only frontal leads (SerumK2), T-wave complexity (T Complex), ST segment levels for leads I, II, V (ST I, ST II, ST V), and 7 heart rate variability (HRV) metrics. These 7 HRV metrics were standard deviation of normal to normal intervals (SDNN), total power, very low frequency power, low frequency power, high frequency power, normalized low frequency power, and normalized high frequency power. Controls were matched by gender, age (±5 years), admission to the same hospital unit within the same month, and the same major diagnostic category. A research ECG analysis software program developed by co-author D M was used to automatically extract the metrics. The absolute value for each ECG metric, and the duration, terminal value, and slope of the dominant trend for each ECG metric, were derived and tested as the alarm conditions. The maximal true positive rate (TPR) of detecting cardiac arrest at a prescribed maximal false positive rate (FPR) based on the trending conditions was reported. Lead time was also recorded as the time between the first time alarm condition was triggered and the event of cardiac arrest.While conditions based on the absolute values of ECG metrics do not provide discriminative information to predict bradyasystolic cardiac arrest, the trending conditions can be useful. For example, with a max FPR = 5.0%, some derived alarms conditions are: trend duration of PR > 2.8 h (TPR = 48.2%, lead time = 10.0 ± 6.6 h), trend duration of QRSdur > 2.7 h (TPR = 40.7%, lead time = 8.8 ± 6.2 h), trend duration of RR > 3.5 h (TPR = 51.9%, lead time = 6.4 ± 5.5 h), trend duration of T Complex > 2.9 h (TPR = 40.7%, lead time = 6.8 ± 5.5 h), trend duration of ST I > 3.0 h (TPR of 51.9%, lead time = 8.4 ± 8.0 h), trend duration of SDNN > 3.6 h (TPR of 40.7%, lead time = 11.0 ± 8.6 h), trend duration of HRV total power > 3.0 h (TPR of 25.9%, lead time = 7.5 ± 8.1 h), terminal value of ST I < −56 µV (TPR = 22.2%, lead time = 12.8 ± 8.3 h), and slope of QR > 19.4 ms h−1 (TPR = 25.9%, lead time = 6.7 ± 6.9 h). Eleven trend duration alarms, eight terminal value alarms, and ten slope alarms, achieved a positive TPR with zero FPR. Furthermore, these alarms conditions with zero PFR can be combined by the ‘OR’logic could further improve the TPR without increasing the FPR.The trend duration, terminal value, and slope of the dominant trend of the ECG metrics considered in this study are able to predict a subset of patients with bradyasystolic cardiac arrests with low or even zero FPR, which can be used for developing new ECG alarms.

Effects of Personal Exposure to Ambient Fine Particulate Matter on Acute Change in Nocturnal Heart Rate Variability in Subjects Without Overt Heart Disease

The immediate effect within minutes to hours of personal exposure to ambient fine particulate matter (PM2.5) on cardiac autonomic function is limited, particularly at night. Our study aimed to assess the lagged association between personal exposure to PM2.5 and nocturnal heart rate variability. Repeated measures panel study among 21 community adults recruited from a local health clinic during the period of March 1, 2004, to August 31, 2004, in Boston, Massachusetts, in the United States. Ambulatory electrocardiogram and continuous monitoring of personal exposure to PM2.5 and were measured for up to 2 consecutive days. We calculated 5-minute time-specific average PM2.5 exposure for each participant. Mixed-effects models were fit for 5-minute SD of normal-to-normal intervals (SDNN) and 5-minute heart rate in relation to 5-minute PM2.5 exposure lagged in 5-minute intervals up to 4 hours. We found an 8.4% decrease in nocturnal SDNN (95% confidence interval [CI] -11.3% to -5.5%) and a 1.9% increase in nighttime heart rate (95% CI 1.1% to 2.7%) for an interquartile range increase in PM2.5 (13.6 μg/m(3)), after adjusting for confounders. Significant decreases in nocturnal SDNN associated with PM2.5 exposure occurred within 2.5 hours. The largest decrease in nocturnal SDNN of -12.8% (95% CI -16.4 to -9.1%) that was associated with PM2.5 exposure was found with a lag of 25 minutes. Rapid changes in nocturnal heart rate variability associated with personal PM2.5 exposure occurred within the previous 2.5 hours, with the largest effects at 25 minutes, suggesting immediate cardiac autonomic effects of fine particulate exposure.

Validity of (Ultra-)Short Recordings for Heart Rate Variability Measurements.

ObjectivesIn order to investigate the applicability of routine 10s electrocardiogram (ECG) recordings for time-domain heart rate variability (HRV) calculation we explored to what extent these (ultra-)short recordings capture the “actual” HRV.MethodsThe standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive differences (RMSSD) were measured in 3,387 adults. SDNN and RMSSD were assessed from (ultra)short recordings of 10s(3x), 30s, and 120s and compared to 240s–300s (gold standard) measurements. Pearson’s correlation coefficients (r), Bland-Altman 95% limits of agreement and Cohen’s d statistics were used as agreement analysis techniques.ResultsAgreement between the separate 10s recordings and the 240s-300s recording was already substantial (r = 0.758–0.764/Bias = 0.398–0.416/d = 0.855–0.894 for SDNN; r = 0.853–0.862/Bias = 0.079–0.096/d = 0.150–0.171 for RMSSD), and improved further when three 10s periods were averaged (r = 0.863/Bias = 0.406/d = 0.874 for SDNN; r = 0.941/Bias = 0.088/d = 0.167 for RMSSD). Agreement increased with recording length and reached near perfect agreement at 120s (r = 0.956/Bias = 0.064/d = 0.137 for SDNN; r = 0.986/Bias = 0.014/d = 0.027 for RMSSD). For all recording lengths and agreement measures, RMSSD outperformed SDNN.ConclusionsOur results confirm that it is unnecessary to use recordings longer than 120s to obtain accurate measures of RMSSD and SDNN in the time domain. Even a single 10s (standard ECG) recording yields a valid RMSSD measurement, although an average over multiple 10s ECGs is preferable. For SDNN we would recommend either 30s or multiple 10s ECGs. Future research projects using time-domain HRV parameters, e.g. genetic epidemiological studies, could calculate HRV from (ultra-)short ECGs enabling such projects to be performed at a large scale.

Female Sexual Function and Heart Rate Variability

Few studies have examined the associations of resting heart rate variability (HRV) with female sexual function and behavior. Therefore, we welcome the recent study finding that women with below average resting HRV (as assessed by the standard deviation of NN intervals; SDNN) had lower sexual arousal and lower global sexual function than women with average or above average SDNN (while viewing a neutral film) (Stanton et al. 2015). The SDNN reflects relatively lower sympathetic activity and/or relatively higher parasympathetic activity. Those authors noted the lack of studies on female sexuality and HRV, but missed citing an important study which explored the associations of HRV with women’s frequency of orgasm produced by several different sexual behaviors (Costa and Brody 2012). In that study, it was found that women who had any orgasm triggered by penile-vaginal intercourse (PVI) without simultaneous clitoral masturbation (henceforth, vaginal orgasm) in the past month had higher resting HRV (as assessed by the standard deviation of heart rate, a relatively similar index of HRV) than women who did not have a vaginal orgasm in the past month (Costa and Brody 2012). Of note, orgasm produced by other sexual behaviors including PVI with concurrent clitoral masturbation for the orgasm, clitorally-focused partnered masturbation, oral sex, solitary masturbation, and anal sex were unrelated to resting HRV. Orgasm from vaginally-focused masturbation by the woman’s partner was nearly significantly associated with higher HRV, but this marginal association disappeared in multivariate analyses controlling for the other orgasm trigger frequencies, resulting in only vaginal orgasm being associated with women’s greater resting HRV. These findings were discussed in terms of lower HRV being a reflection of pathophysiological processes that can impair female orgasmic responsiveness specifically during PVI (Costa and Brody 2012). This raises the possibility that vaginal responsiveness is more easily adversely affected by psychological and physiological dysfunctional processes than responding to direct clitoral masturbation. The vagus nerve (the main driver of the parasympathetic nervous system influences on HRV) transmits afferent sensory information from the proximal vagina and cervix to the brain, but is not stimulated by the clitoris (Komisaruk and Whipple 1998; Komisaruk et al. 2004). Given that appropriate afferent vagal stimulation might increase (or ‘‘tune’’) efferent vagal activity on a relatively long-term basis (Gellhorn 1967), it is plausible that PVI may enhance HRV with concomitant health benefits (Costa and Brody 2012). These findings are congruent with another study finding that greater resting HRV (standard deviation of heart rate) was associated with greater PVI frequency in a sample of both sexes, and the sex of the research participant was not a significant confounding variable (Brody and Preut 2003). Unlike in the study by Stanton and colleagues, in these two studies, resting HRV was measured without an inserted vaginal probe (Brody and Preut 2003; Costa and Brody 2012), which Stanton and colleagues listed as a potential confounder in their own study. In a large nationally representative Czech sample, female sexual arousal disorder was related to lack of history of vaginal orgasm and difficulties in focusing on & Rui M. Costa rmscosta@gmail.com

계류 유산 후 한방치료 위해 내원한 환자의 Heart Rate Variability(HRV) 특성 연구

Objectives This study aims to analyze Heart Rate Variability (HRV) in women after missed abortion compared with healthy women Methods We studied 35 women who visited Kang-Nam Kyung-Hee Korean Hospital after missed abortion from 01 January 2012 to 28 February 2015 (missed abortion group) and 35 normal women visiting medical examination center from 1 January 2014 to 31 December 2014 (Normal Group). We measured HRV of each women and investigated the difference of HRV between two groups. Results The standard deviation of NN intervals (SDNN) in Missed abortion group is lower than normal group. The square root of the mean square difference of successive NNs (RMSSD) in Missed abortion group is lower than normal group. However there was no significant difference. Total Power (TP) and Low frequency power (LF) is significantly lower in Missed abortion group compared with normal group. High frequency power (HF), Very low frequency power (VLF) and LF/HF ratio in missed abortion group is lower than normal group. but There was no significant difference. Conclusions Missed abortion group is lower in function of overall autonomic nervous system, especially sympathetic nerve.

위축성 질염을 호소하는 여성의 HRV 특성 연구

Objectives This study is performed to recognize the relationship between atrophic vaginitis and stress that have an affect on autonomic nervous system. Methods We studied 47 patients who visited Kangnam Kyunghee Korean Hospital Medical Examination Center from November, 2013 to June, 2014. They were devided into two groups, atrophic vaginitis group (AV, n=18) and non-atrophic vaginitis group (NAV, n=29). We compared the result of HRV between the two groups. Results The mean of The standard deviation of NN intervals (SDNN), the square root of the mean squared difference of successive NNs (RMSSD) in AV group was lower than NAV group, but there was no significant difference between the two groups. Total power (TP), low frequency (LF) and very low frequency (VLF) of AV group was significantly lower than NAV group. There was no significant difference in high frequency (HF). Conclusions Women with atrophic vaginitis is expected to have low adaptive capacity against stress.

P184. Heart rate variability and its modulation by auricular branch of vagus nerve stimulation in Parkinson’s disease

Objective Brainstem nuclei, especially the efferent dorsal motor nucleus of the vagal nerve may degenerate early in the course of Parkinson’s disease (PD). The vagus nerve includes axons which emerge from or converge onto different efferent and afferent brainstem nuclei, all functionally and anatomically interconnected. The auricular branch of the vagus nerve (ABVN) is known to be connected to autonomic regulation of cardiac rhythm. In the present prospective, cross-sectional observational study we tested heart rate variability (HRV) at rest and the influence ABVN stimulation. Methods Fifty patients with PD (age 64 ± 9 years, 21 females Hoehn & Yahr stage 2.3 ± 0.7, UPDRS III 20.9 ± 7.2, disease duration 6.4 ± 4.5 y) and 50 controls (age 64 ± 11 y, 21 females) were investigated. RR intervals were measured on electrocardiograms at normal breathing for 3 min under resting condition and for around 317 min during left or right transcutaneous ABVN stimulation. Several indices of the heart rate variability (HRV) were automatically computed (time and frequency domain): standard deviation of NN intervals (SDNN), RR-intervals/maximal frequency (HFV index), power spectral analysis in the low (ln(LF), 0.05–0.15 Hz) and in the high frequency spectrum (ln(HF), 0.15–0.5 Hz) and the low frequency/high frequency ratio (ln(LF/HF) ratio). Results Most HRV parameters were lower in PD patients compared to controls: SDNN ( p = 0.027), TINN ( p = 0.013), HRV index ( p = 0.003), LF ( p = 0.014) and HF (p = 0.039). The ln(LF/HF) ratio, that is believed to mirror sympathovagal balance did not differ between both groups ( p = 0.137). However, a significant decrease of ln(LF/HF) ratio during right ABVN stimulation in comparison to the resting condition across all subjects was found ( p = 0.002), but not following left ABVN stimulation ( p = 0.238). Other parameters were not significantly influenced by right or left ABVN stimulation. UPDRS III correlated negatively with ln(LF) ( r = −0.369, p = 0.014) and ln(HF) ( r = −0.291, p = 0.050) indicating a (weak) association between impairment in cardiac autonomic modulations and motor deficit. Conclusions Heart rate variability is considerably impaired in PD. Parasympathetic activity seems to be relatively enhanced over sympathetic activity by ABVN stimulation. However, our findings do not point to prominent dysfunction of processing afferent information from ABVN and its connected parasympathetic efferent pathway in PD.

Heart rate recovery and parasympathetic modulation in boys and girls following maximal and submaximal exercise.

This study examined heart rate recovery (HRR) and heart rate variability (HRV) following submaximal and maximal exercise in boys (n=13; 10.1±0.8 years) and girls (n=12; 10.1±0.7 years). Participants completed 10min of supine rest followed by a graded exercise test to maximal effort. On a separate day, participants performed submaximal exercise at ventilatory threshold. Immediately following both exercise bouts, 1-min HRR was assessed in the supine position. HRV variables were analyzed under controlled breathing in the time and frequency domains over the final 5min of rest and recovery. There were no significant differences in HRR following maximal and submaximal exercise between boys (58±8 and 59±8 beatsmin(-1), respectively) and girls (54±6 and 52±19 beatsmin(-1), respectively). There also were no significant interactions between groups from rest to recovery from maximal exercise for any HRV variables. However, there was a difference in the response between sexes from rest to recovery from submaximal exercise for log transformed standard deviation of NN intervals (lnSDNN) and log transformed total power (lnTP). No differences were observed for lnSDNN at rest (boys=4.61±0.28 vs. girls=4.28±0.52ms) or during recovery (lnSDNN: boys 3.78±0.46 vs. girls 3.87±0.64ms and lnTP: boys 7.33±1.09 vs. girls; 7.44±1.24ms(2)). Post hoc pairwise comparisons showed a significant difference between boys and girls for lnTP at rest (boys=9.14±0.42 vs. girls=8.30±1.05ms(2)). Parasympathetic modulation was similar between boys and girls at rest and during recovery from exercise, which could explain similarities observed in HRR.

Randomized controlled trial of heart rate variability biofeedback in cardiac autonomic and hostility among patients with coronary artery disease

Hostility is a psychosocial risk factor that may decrease heart rate variability (HRV) in coronary artery disease (CAD) through cardiac autonomic imbalance. Heart rate variability biofeedback (HRV-BF) increases HRV indices and baroreflex gain. This study examines the effectiveness of HRV-BF in restoring cardiac autonomic balance and decreasing hostility among patients with CAD. One hundred and fifty-four patients with CAD were assigned randomly to receive 6 weeks of HRV-BF, in addition to the standard medical care received by the wait-list control (WLC) group. A 5-min electrocardiogram, blood pressure, and hostility were assessed pre-intervention, post-intervention, and at 1-month follow-up. The standard deviation of normal-to-normal intervals (SDNN), low frequency (LF), and log LF at post-intervention was significantly higher than that at pre-intervention in the HRV-BF group. Baseline log LF was significantly higher post-intervention and at follow-up after HRV-BF training than at pre-intervention. The treatment curve of log LF pre-session increased significantly after session 2, which was maintained to post-intervention. Expressive hostility, suppressive hostility, and hostility total score at post-intervention and one-month follow-up after HRV-BF were significantly lower than at pre-intervention. This study showed increased HRV and decreased expressive and suppressive hostility behavior in patients with CAD following HRV-BF.

Pulmonary Function And Heart Rate Variability Responses To Low- And High-intensity Cycling In Diesel Exhaust

INTRODUCTION: Exposure to diesel exhaust (DE) prior to exercise increases exercise heart rate and attenuates exercise-induced bronchodilation. However, the effects of exercise combined with air pollution on pulmonary function and heart rate variability (HRV) are unclear. Furthermore, it is often assumed that increases in exercise intensity will increase the dose of air pollution, thus magnifying the resultant health effects. However, how the effects of DE on pulmonary function and HRV are modulated by exercise intensity is unknown. PURPOSE: To determine the effects to low- and high-intensity cycling in DE on pulmonary function and HRV. METHODS: Eighteen males performed 30-minute trials of low (30% VO2peak power) and high-intensity (60% VO2peak power) cycling and a resting control condition. For each subject, each trial was performed once breathing filtered air (FA) and once breathing DE (300ug/m3 of PM2.5), for a total of 6 trials. Pulmonary function and HRV were measured before, immediately after, and 1 h, and 2 h post-exposure to DE or FA. Time domain measures of HRV included the standard deviation of normal-to-normal intervals (SDNN), the root mean square of the mean differences in successive N-N intervals (RMSSD), and the HRV triangular index. Frequency domain analysis included low frequency power (LFP: 0.04–0.15 Hz), high frequency power (HFP: 0.15–0.40 Hz) as well as total power (TP). Additionally, LF and HF normalized units (LFnu, HFnu), and LF/HF ratios were determined. RESULTS: Exposure to DE had no significant effect on pulmonary function or HRV (p<0.05). As expected all time and frequency domain indices of HRV significantly decreased following high-intensity exercise (p<0.05; Pre to post high-intensity exercise: SDNN 1018.7 vs. 730.1 ms, RMSSD 65.2 vs. 19.5 ms, HRV triangular index 14.3 vs. 7.2, LFP 1408.8 vs. 455.7 ms2, HFP 1487.0 vs. 391.1 ms2, TP 4949.0 vs. 1152.8 ms2, HFnu 44.5 vs. 19.8). The exception to this pattern was LFnu and LF/HF ratio, which significantly increased following high-intensity exercise (p<0.05; Pre to post high-intensity exercise: LFnu 51.7 vs. 71.8, LF/HF 1.49 vs. 4.52). CONCLUSION: These data suggest that acute exposure to DE during exercise does not affect pulmonary function or HRV. Furthermore, performing high intensity exercise does not potentiate the effects of DE.