川崎病患儿的心率变异性指标与血清NT-proBNP及cTnI水平的相关性

目的:研究川崎病患儿的心率变异性指标与血清氨基末端脑钠肽前体(NT-pro BNP)及肌钙蛋白I(cTnI)水平的相关性,为临床诊疗提供依据。方法:选取2013年7月到2015年7月我院收治的川崎病患儿120例为研究组,根据患者是否存在冠状动脉损害分为A组(有冠状动脉损害)60例和B组(无冠状动脉损害)60例,同时选取同期健康体检儿童60例为对照组,比较各组窦性N-N间期标准差(SDNN)、5min N-N间期平均值标准差(SDANN)、极低频功率(VLF)、低频功率(LF)、高频功率(HF)、NT-proBNP水平以及cTnI水平。结果:研究组SDNN、SDANN、VLF、LF以及HF显著低于对照组,且A组显著低于B组,差异具有统计学意义(P0.05);研究组NT-proBNP水平和cTnI水平显著高于对照组,且A组显著高于B组,差异具有统计学意义(P0.05);研究组NT-proBNP与SDNN和HF呈负相关关系(P0.05),cTnI与SDNN和HF呈负相关关系(P0.05)。结论:心率变异性指标与川崎病患儿冠状动脉损害有关,与NT-proBNP、cTnI呈负相关关系。     

体位改变对Beagle犬心脏自主神经控制的影响

目的观察体位改变对Beagle犬心脏自主神经控制的影响。方法利用大动物无创生理遥测技术,监测清醒活动状态下雌性Beagle犬在静态姿势（lying、standing、sitting、hanging）和运动（walking）姿势下的心电图（ECG）,并用HRV功率谱分析其自主神经功能。结果在静态姿势下,Beagle犬RR间期（RRI）、RR间期的标准差SDNN（SDNN）、相邻RR间期差值平方和的均方根RMSSD（RMSSD）、相邻R-R间期差值〉50 ms的窦性个数占心搏总数的百分比pNNabs（50）（pNNabs（50））、TP总功率（TP）、VLF极低频功率（VLF）、标准化高频功率（HFnorm）均明显高于运动状态（P〈0.05,P〈0.01）,而心率（HR）、标准化低频功率（LFnorm）和低频功率/高频功率（LF/HF）平衡指数则明显低于运动状态（P〈0.05,P〈0.01）。结论不同体位姿势在静息状态下以迷走神经活动兴奋为主,相反,在运动状态下以交感神经活动兴奋为主;体位姿势改变能引起心率的变化,必然影响心脏自主神经控制能力,其主要取决于迷走神经活动强弱有关,且导致LF/HF均衡性的破坏。     

Analysis of Heart Rate Variability in Masked Hypertension

To investigate heart rate variability (HRV) in patients with masked hypertension (MH), participants were classified based on clinic and 24-h ambulatory blood-pressure monitoring: essential hypertension (EH, n = 40; MH, n = 36) and normotension (NT, n = 48). The HRV parameters were observed using a 24-h Holter monitor. Compared with NT controls, the parameters of HRV (SDNN, SDANN, SDNN Index, RMSSD, HF) and parameters in EH and MH patients had significantly decreased. No statistically significant difference in the HRV parameters was found between the EH and MH groups. The changes in HRV parameters show cardiac autonomic nerve dysfunction in patients with MH.     

电刺激迷走神经对蟾蜍心率和心率变异的影响

目的:观察不同频率迷走神经刺激对蟾蜍离体心脏的心率及心率变异的影响。方法:将蟾蜍心脏和右侧迷走交感干离体后,以不同频率电刺激神经,记录心电图曲线并作心率变异性(HRV)分析。结果:交感神经阻断后,电刺激迷走交感干,心率(HR)显著下降(P0.01),全部正常心动周期的标准差(SDNN)和相邻正常心动周期差值的均方根(RMSSD)显著升高(P0.01),不同频率刺激组之间没有明显差异;与对照组相比,各指标变化较大;给药组0.2Hz时高频(HF)显著升高(P0.01),低频/高频比值(LF/HF)明显降低(P0.05),0.8Hz时HF和LF/HF接近刺激前水平。结论:一定范围内增加刺激频率,迷走神经降低心率的作用增强;没有交感神经调节条件下的迷走神经对心率和心率变异的调节可能存在不同的机制。     

Heart rate variability after radiofrequency ablation of epicardial ganglionated plexuses on the ovine left atrium

Background

Ganglionated plexuses (GP) are terminal parts of cardiac autonomous nervous system (ANS). Radiofrequency ablation (RFA) for atrial fibrillation (AF) possibly affects GP. Changes in heart rate variability (HRV) after RFA can reflect ANS modulation.

Methods

Epicardial RFA of GP on the left atrium (LA) was performed under the general anesthesia in 15 mature Romanov sheep. HRV was used to assess the alterations in autonomic regulation of the heart. A 24???hour ECG monitoring was performed before the ablation, 2 days after it and at each of the 12 following months. Ablation sites were evaluated histologically.

Results

There was an instant change in HRV parameters after the ablation. A standard deviation of all intervals between normal QRS (SDNN), a square root of the mean of the squared differences between successive normal QRS intervals (RMSSD) along with HRV triangular index (TI), low frequency (LF) power and high frequency (HF) power decreased, while LF/HF ratio increased. Both the SDNN, LF power and the HF power changes persisted throughout the 12???month follow???up. Significant decrease in RMSSD persisted only for 3 months, HRV TI for 6 months and increase in LF/HF ratio for 7 months of the follow???up. Afterwards these three parameters were not different from the preprocedural values.

Conclusions

Epicardial RFA of GP’s on the ovine left atrium has lasting effect on the main HRV parameters (SDNN, HF power and LF power). The normalization of RMSSD, HRV TI and LF/HF suggests that HRV after epicardial RFA of GPs on the left atrium might restore over time.

     

Characteristics of the autonomic regulation in humans with different susceptibility to cold

To determine the strained adaptation to cold, the cardiovascular reactivity under local cold exposure and the characteristics of regulation of the circulatory system in persons with high individual susceptibility to cold was studied. It was shown that the subjective characteristics of high susceptibility to cold in the form of initial symptoms of Raynaud’s phenomenon correlated with the symptoms of aggravated and generalized cold-induced vasoconstriction (CIV) during the local cold test. The analysis of the heart rate variability (HRV) in persons with aggravated CIV revealed a decrease in the parameters of the time-domain characteristics of HRV (RRNN, SDNN, RMSSD, pNN₅₀, and coefficient of variation) as well as a decrease in the total power (TP) of the frequency-domain characteristics and the absolute values of the frequency bands (VLF, LF, and HF) with a relative increase of the LF component. This reflects possible changes in the autonomic regulation of the cardiovascular system, which manifest themselves in a reduced contribution of reflectory mechanisms to the heart rate regulation followed by relative predominance of baroreflex regulation. The diagnostic value of aggravated cold-induced vasoconstriction in identifying disorders of adaptation to cold or premorbid state of the cardiovascular system is discussed.     

Effects of Serum Calcium and Magnesium on Heart Rate Variability in Adult Women

The present study was designed to evaluate the association of serum calcium (Ca) and magnesium (Mg) levels with heart rate variability (HRV). One hundred and sixteen adult women were recruited in this cross-sectional study. Serum Ca and Mg levels were measured, and HRV in each time and frequency domain was recorded for 5?min. Mean heart rate and standard deviation of the normal to normal interval (SDNN) and root mean square of differences of successive RR interval (RMSSD) in time domain and total power (TP), low-frequency power (LF), high-frequency power (HF), and LF/HF ratio in frequency domain were compared according to the tertiles of serum Ca and Mg levels and Ca/Mg ratio. The associations between serum Ca and Mg levels and Ca/Mg ratio with HRV were evaluated using regression analyses. Mean heart rate tended to increase from the lowest to the highest tertile of Ca levels (p?=?0.081), whereas it decreased significantly with higher Mg levels (p?=?0.026). Increasing SDNN value was observed from the lowest to the highest tertile of Mg levels (p?=?0.009). SDNN value decreased significantly from the lowest to the highest tertile of Ca/Mg ratio (p?=?0.030). Participants in the lowest tertile of Ca/Mg ratio had significantly higher TP and LF values compared to those in the middle and highest tertiles (p?<?0.05). Decreasing SDNN, TP, and LF values were significantly associated with higher Ca/Mg ratios (p?<?0.05). Associations of serum Mg level and Ca/Mg ratio with HRV could be one of the mechanisms involved in cardiovascular diseases.     

The nature of very low frequency component of the heart rate variability and the role of sympathetic-parasympathetic interactions

A method of separate monitoring "instant" changes of the VLF, LF and HF power spectral components of heart rate variability, has been developed. The power of the LF and HF spectral components were proved to be continuously changing. The period of these power fluctuations could stay within 15 to 150 sec. Comparison of the heart rate variability spectrum with LF and HF spectral components power fluctuations' spectrums has shown that the frequencies of the LF and HF spectral components power fluctuations stay within the VLF range. The co-operative spectrum form of these fluctuations repeats the form of the VLF peak. In cases when the LF and HF spectral components power fluctuations' periods do not coincide, VLF has two peaks. The frequency of one VLF peak coincides with frequency of the HF power fluctuations, and the frequency of another--with the frequency of LF power fluctuations.     

Normal ranges and reproducibility of statistical, geometric, frequency domain, and non-linear measures of 24-hour heart rate variability.

Diabetic cardiovascular autonomic neuropathy (CAN) carries an increased risk of mortality. The early detection and characterization of CAN has traditionally been based on the results of autonomic reflex tests (AFTs). A variety of different measures to quantify 24-hour heart rate variability (HRV) have recently been introduced, but their normal ranges, reliability, and validity in patients with CAN have not been adequately studied. We established the normal ranges of statistical (SDNN index, CV, SNN50, RMSSD), geometric (triangular index (TI), triangular interpolation (TINN), top angle index [TAI]), frequency domain (spectral power in the VLF, LF, and HF bands, LF/HF ratio, LF in normalized units [NU]), and non-linear measures (CV1 and CV2 of the Poincaré plot) of 24-hour HRV in 94 healthy control subjects. Day-to-day reproducibility was evaluated on two occasions in 17 healthy subjects and 9 diabetic patients. The parameters of HRV were computed over time periods representing the day (6:00-24:00 hours), night (00:00-6:00 hours), and 24 hours in total. The results of all indexes, except for the LF/HF ratio and LF-NU, declined significantly with increasing age (p<0.05), but were independent of sex and BMI. The statistical, geometric, and non-linear measures (p<0.05), but not the frequency-domain parameters decreased significantly with increasing heart rate. Since the HRV data showed log normal distribution, log transformation was used to define the age-related lower limits of normal at the 2.5th centile. Intraindividual reproducibility was highest for the geometric measures. The nonlinear and statistical parameters also showed high reliability, except for the SNN50. The repeatability of the frequency domain measures was somewhat lower but still satisfactory. Reproducibility was lower in the diabetic than in the control group, higher during the day than during the night, and better than that reported previously for the AFTs. In conclusion, in healthy subjects the measures of 24-h HRV are not related to sex or BMI, but strongly dependent on age and heart rate, the latter except for the frequency domain measures. The majority of the HRV measures, in particular the geometric parameters, show a relatively high intraindividual reproducibility which underlines their suitability for the use in prospective studies.     

冠心病患者动态心电图参数与血清YKL-40、LTBP-2水平的关系研究

摘要 目的：探讨冠心病患者动态心电图参数与血清甲壳质酶蛋白40（YKL-40）、潜在转化生长因子结合蛋白2（LTBP-2）水平的关系。方法：选取本院2020年3月至2023年4月154例冠心病患者纳入冠心病组（其中单支病变38例,双支病变57例,多支病变59例;Gensini积分评估冠状动脉狭窄程度包括轻度42例,中度60例,重度52例）,另选择于本院进行健康体检者90例纳入对照组,所有纳入对象均接受动态心电图检查,并检测血清YKL-40、LTBP-2水平,分析冠心病患者动态心电图参数与血清指标的关系。结果：冠心病组24 h内全部正常心动周期的标准差（SDNN）、每5 min正常R-R间期标准差（SDANN）、相邻正常心动周期差值均方根（RMSSD）、相邻2个正常心动周期差值＞50 ms个数百分比（PNN50）水平低于对照组,低频与高频功率之比（LF/HF）水平高于对照组（P＜0.05）;不同冠脉病变狭窄范围患者SDNN、SDANN、RMSSD、PNN50水平比较,多支病变＜双支病变＜单支病变,LF/HF水平比较,多支病变＞双支病变＞单支病变（P＜0.05）;不同冠脉病变狭窄程度患者SDNN、SDANN、RMSSD、PNN50水平比较,重度＜中度＜轻度,LF/HF水平比较,重度＞中度＞轻度（P＜0.05）;冠心病组血清YKL-40、LTBP-2水平高于对照组,且多支病变＞双支病变＞单支病变（P＜0.05）;不同冠脉病变狭窄程度患者血清YKL-40、LTBP-2水平比较,重度＞中度＞轻度（P＜0.05）;冠心病患者动态心电图参数SDNN、SDANN、RMSSD、PNN50水平与血清YKL-40、LTBP-2水平呈现负相关,LF/HF水平与血清YKL-40、LTBP-2水平呈现正相关（P＜0.05）。结论：冠心病患者血清YKL-40、LTBP-2呈高表达,且其表达水平随冠脉病变狭窄范围和严重程度增加而升高,与动态心电图指标SDNN、SDANN、RMSSD、PNN50水平呈现负相关,与LF/HF水平呈现正相关。     

Acute effects of stretching exercise on the heart rate variability in subjects with low flexibility levels

The study investigated the heart rate (HR) and heart rate variability (HRV) before, during, and after stretching exercises performed by subjects with low flexibility levels. Ten men (age: 23 ± 2 years; weight: 82 ± 13 kg; height: 177 ± 5 cm; sit-and-reach: 23 ± 4 cm) had the HR and HRV assessed during 30 minutes at rest, during 3 stretching exercises for the trunk and hamstrings (3 sets of 30 seconds at maximum range of motion), and after 30 minutes postexercise. The HRV was analyzed in the time ('SD of normal NN intervals' [SDNN], 'root mean of the squared sum of successive differences' [RMSSD], 'number of pairs of adjacent RR intervals differing by >50 milliseconds divided by the total of all RR intervals' [PNN50]) and frequency domains ('low-frequency component' [LF], 'high-frequency component' [HF], LF/HF ratio). The HR and SDNN increased during exercise (p < 0.03) and decreased in the postexercise period (p = 0.02). The RMSSD decreased during stretching (p = 0.03) and increased along recovery (p = 0.03). At the end of recovery, HR was lower (p = 0.01), SDNN was higher (p = 0.02), and PNN50 was similar (p = 0.42) to pre-exercise values. The LF increased (p = 0.02) and HF decreased (p = 0.01) while stretching, but after recovery, their values were similar to pre-exercise (p = 0.09 and p = 0.3, respectively). The LF/HF ratio increased during exercise (p = 0.02) and declined during recovery (p = 0.02), albeit remaining higher than at rest (p = 0.03). In conclusion, the parasympathetic activity rapidly increased after stretching, whereas the sympathetic activity increased during exercise and had a slower postexercise reduction. Stretching sessions including multiple exercises and sets acutely changed the sympathovagal balance in subjects with low flexibility, especially enhancing the postexercise vagal modulation.     

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

Objectives

In 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.

Methods

The 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.

Results

Agreement 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.

Conclusions

Our 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.     

摄食行为对小型猪心脏自主神经功能的影响

目的观察摄食行为对小型猪心脏自主神经功能的影响。方法利用大动物无创遥测技术观察清醒活动状态下小型猪摄食前（BI）、摄食过程中（IP）、摄食后（AI）、AI 2 h和AI 4h的心电图（ECG）和自主活动,并用HRV功率谱分析其自主神经功能。结果与摄食前比较,小型猪摄食过程中心率（HR）、自主活动和标准化低频成分（LFnu）明显增加,RR间期（RRI）、总功率（TP）、极低频成分（VLF）、高频成分（HF）明显减少,LF/HF比值明显升高;且随着摄食后恢复时间的延长,小型猪HR、自主活动、LFnu均有所降低,而RRI、TP、VLF、HF均有所升高,LF/HF比值逐渐降低,并在摄食后2 h、4 h时变化显著;相关分析显示摄食行为与TP、VLF、HF、LF和LF/HF密切相关,多元线性逐步回归分析亦显示摄食行为与VLF、LF/HF和TP密切相关,且VLF起主要作用。结论小型猪摄食行为不仅影响心脏活动;而且能引起小型猪心脏自主神经控制能力发生改变,其中VLF在摄食行为过程中占有重要作用。     

Associations between Heart Rate Variability Parameters and Housing- and Individual-Related Variables in Dairy Cows Using Canonical Correspondence Analysis

We investigated the associations between heart rate variability (HRV) parameters and some housing- and individual-related variables using the canonical correspondence analysis (CCOA) method in lactating Holstein-Friesian dairy cows. We collected a total of 5200 5-min interbeat interval (IBI) samples from 260 animals on five commercial dairy farms [smaller-scale farms with 70 (Farm 1, n = 50) and 80 cows per farm (Farm 2, n = 40), and larger-scale farms with 850 (Farm 3, n = 66), 1900 (Farm 4, n = 60) and 1200 (Farm 5, n = 45) cows. Dependent variables included HRV parameters, which reflect the activity of the autonomic nervous system: heart rate (HR), the root mean square of successive differences (RMSSD) in IBIs, the standard deviation 1 (SD1), the high frequency (HF) component of HRV and the ratio between the low frequency (LF) and the HF parameter (LF/HF). Explanatory variables were group size, space allowance, milking frequency, parity, daily milk yield, body condition score, locomotion score, farm, season and physical activity (lying, lying and rumination, standing, standing and rumination and feeding). Physical activity involved in standing, feeding and in rumination was associated with HRV parameters, indicating a decreasing sympathetic and an increasing vagal tone in the following order: feeding, standing, standing and rumination, lying and rumination, lying. Objects representing summer positioned close to HR and LF and far from SD1, RMSSD and HF indicate a higher sympathetic and a lower vagal activity. Objects representing autumn, spring and winter associated with increasing vagal activity, in this order. Time-domain measures of HRV were associated with most of the housing- and individual-related explanatory variables. Higher HR and lower RMSSD and SD1 were associated with higher group size, milking frequency, parity and milk yield, and low space allowance. Higher parity and milk yield were associated with higher sympathetic activity as well (higher LF/HF), while individuals with lower locomotion scores (lower degree of lameness) were characterized with a higher sympathetic and a lower vagal tone (higher HR and LF/HF and lower RMSSD and SD1). Our findings indicate that the CCOA method is useful in demonstrating associations between HRV and selected explanatory variables. We consider physical activity, space allowance, group size, milking frequency, parity, daily milk yield, locomotion score and season to be the most important variables in further HRV studies on dairy cows.     

Heart Rate Variability and Blood Pressure during Dynamic and Static Exercise at Similar Heart Rate Levels

Aim was to elucidate autonomic responses to dynamic and static (isometric) exercise of the lower limbs eliciting the same moderate heart rate (HR) response. Method: 23 males performed two kinds of voluntary exercise in a supine position at similar heart rates: static exercise (SE) of the lower limbs (static leg press) and dynamic exercise (DE) of the lower limbs (cycling). Subjective effort, systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), rate pressure product (RPP) and the time between consecutive heart beats (RR-intervals) were measured. Time-domain (SDNN, RMSSD), frequency-domain (power in the low and high frequency band (LFP, HFP)) and geometric measures (SD1, SD2) as well as non-linear measures of regularity (approximate entropy (ApEn), sample entropy (SampEn) and correlation dimension D2) were calculated. Results: Although HR was similar during both exercise conditions (88±10 bpm), subjective effort, SBP, DBP, MAP and RPP were significantly enhanced during SE. HRV indicators representing overall variability (SDNN, SD 2) and vagal modulated variability (RMSSD, HFP, SD 1) were increased. LFP, thought to be modulated by both autonomic branches, tended to be higher during SE. ApEn and SampEn were decreased whereas D₂ was enhanced during SE. It can be concluded that autonomic control processes during SE and DE were qualitatively different despite similar heart rate levels. The differences were reflected by blood pressure and HRV indices. HRV-measures indicated a stronger vagal cardiac activity during SE, while blood pressure response indicated a stronger sympathetic efferent activity to the vessels. The elevated vagal cardiac activity during SE might be a response mechanism, compensating a possible co-activation of sympathetic cardiac efferents, as HR and LF/HF was similar and LFP tended to be higher. However, this conclusion must be drawn cautiously as there is no HRV-marker reflecting “pure” sympathetic cardiac activity.     

五指山小型猪高脂血症模型的心脏自主神经功能变化

目的观察五指山小型猪高脂血症模型的心脏自主神经功能的动态变化,探讨血脂异常对自主神经功能的影响和与昼夜的关系。方法利用高脂饮食诱发五指山小型猪高脂血症,造模后,每2周一次测定小型猪TG、TC、HDL-C和LDL-C和监测动态心电图,并进行24 h和昼夜心率变异性（HRV）分析,以评估小型猪的心脏自主神经功能。结果高脂饮食2周后五指山小型猪血清TC、HDL-C、LDL-C水平均显著升高（P〈0.01）,TG水平亦在高脂饮食后6周显著升高（P〈0.05）,其中,TC、LDL-C在高脂饮食0～4周时呈快速上升,在4～6周达到高峰,8～10周基本稳定并维持在一定水平;HDL-C在高脂饮食0～2周迅速上升并达到高峰,2～10周基本稳定。HRV参数分析结果,时域指标（RRI、SDNN、RMSDD、SDANN、PNN50、SDANN index、STV、LTV）和频域指标（VLF、LF、HF和TP）均渐进性显著降低（P〈0.05,P〈0.01）,LF/HF升高（P〈0.05）,夜间HRV参数变化程度均高于白天;相关分析显示HRV各参数与TC、LDL-C、TC/HDL-C、LDL-C/HDL-C具有显著的相关性（P〈0.05,P〈0.01）,经多元线性逐步回归分析发现,SDNN与TC、LDL-C、TC/HDL-C、LDL-C/HDL-C比值的相关性依次为0.673、0.672、0.665、0.681。结论高脂饮食诱发五指山小型猪高脂血症的血脂异常可引起自主神经功能的下降和紊乱,自主神经功能的紊乱程度与高血脂状态的持续时间有关;血脂异常所致心血管疾病的危险程度夜间高于白天;HRV降低与TC、LDL-C、TC/HDL-C和LDL-C/HDL-C比值升高呈一定的依赖性,SDNN降低可作为预测高脂血症引发心血管病风险的独立相关指标。     

斜角肌间臂丛阻滞影响心率变异性的危险因素分析

摘要 目的：本研究旨在探讨斜角肌间臂丛阻滞影响心率变异性的危险因素及Logistic回归分析。方法：选取2021年5月至2022年3月于我院接受肩关节开放手术治疗的患者60例作为研究对象,按照麻醉方式不同随机分为实验组和对照组2组,其中实验组患者给与超声引导下斜角肌间臂丛神经阻滞,对照组患者进行单纯斜角肌间臂丛神经阻滞,统计患者的一般临床资料,对比分析阻滞前后心率变异指标、SpO₂、心率和平均动脉压水平;同时研究危险因素与心率变异性之间的关系。结果：斜角肌间臂丛阻滞影响心率变异性的单因素分析显示,危险因素与性别、平均年龄、BMI、总胆固醇、甘油三酯、高密度脂蛋白、低密度脂蛋白、合并慢性病（糖尿病、高血压）、吸烟史和饮酒史无关（P>0.05）,镇痛维持时间较短、运动恢复时间较长、阻断节数较少的斜角肌间臂丛阻滞患者更易表现出心率变异性（P<0.05）。阻滞后,实验组LF、HF、LF/HF、RMSSD、SDNN和PNN50 %显著低于对照组（P<0.05）,而阻滞后SpO₂、心率和平均动脉压比较无差异（P>0.05）。影响心率变异性危险因素的多因素为镇痛维持时间（OR=6.224,P=0.001<0.05）、运动恢复时间（OR=9.556,P=0.002<0.05）、阻断节数（OR=7.591,P=0.001<0.05）。结论：斜角肌间臂丛阻滞出现心率变异性与镇痛维持时间、运动恢复时间、阻断节数有关。     

A trial of the use of aekol in preventing psychoautonomic disorders

Autonomic dysfunction in chronic emotional stress is well documented. The aim of this study was to analyze the effects of natural antioxidant vitamin E (aekol). Twenty persons (16 women and 4 men, mean age 38 +/- 4 years) who reported recent occurrence of emotional stress were examined before and after a 4-week treatment with aekol (5 ml twice a day). Heart rate variability (taking into account very low-frequency (VLF, 0.003-0.04 Hz), low-frequency (LF, 0.04-0.15 Hz), and high-frequency (HF, 0.15-0.40 Hz) components) was computed from the power spectra (5-min epochs) of the EKG recorded in the patients in supine position. After the treatment, the HF power of the heart rate variability (an index of cardiac parasympathetic activity) increased (p < 0.05), whereas the VLF power (an index of the cerebral sympathetic activity) decreased (p < 0.01). The decrease in the VLF was accompanied by a reduction of anxiety level (p < 0.01). According to our hypothesis, the absolute and relative power of the VLF can be used as an index of anxiety or cerebral sympathetic activity, which significantly decreases after the aekol treatment.     

The Short‐Term Effect of Occupational Levels of 50 Hz Electromagnetic Field on Human Heart Rate Variability

Previous studies have indicated that there is no consensus on the effects of extremely low‐frequency electromagnetic (ELF‐EMF) exposure on the cardiovascular system. This study aimed to explore the short‐term effect of ELF‐EMF exposure on heart rate (HR) and HR variability (HRV). The sample consisted of 34 healthy males aged 18–27 years. The participants were randomly assigned to the EMF (n = 17) or the Sham group (n = 17). We employed a double‐blind repeated‐measures design consisting of three 5 min experimental periods. The chest region of each individual in the EMF group was exposed to 50 Hz, 28 μT, linear polarized, continuous EMF during the EMF exposure period. HR and HRV data were recorded continuously by using a photoplethysmography sensor. Within‐subject statistical analysis indicated a significant HR deceleration in both the EMF and Sham groups. However, the standard deviation of the NN intervals (SDNN), root mean square of successive differences (RMSSD), low‐frequency (LF), and high‐frequency (HF) powers increased only in the EMF group and remained stable in the Sham group. We also compared the same HRV indices measured during the EMF and Sham periods between the two experimental groups. The between‐subject analysis results demonstrated significantly higher SDNN, RMSSD, LF, and HF values in the EMF group than in the Sham group. The LF/HF ratio did not change significantly within and between groups. On the basis of these results, we concluded that short‐term exposure of the chest region to ELF‐EMF could potentially enhance parasympathetic predominance during the resting condition. Bioelectromagnetics. 2021;42:60–75. © 2020 Bioelectromagnetics Society.     

小剂量洋地黄对急性心肌梗死PCI术后合并心力衰竭患者心率变异性的影响

目的:探讨早期应用小剂量洋地黄类药物对急性心肌梗死(Acute myocardial infarction,AMI)行经皮冠状动脉介入治疗(Percutaneous coronary intervention,PCI)术后合并心力衰竭患者心率变异性(Heart rate variability,HRV)的影响。方法:入选32例在发病24小时内接受PCI治疗且合并心力衰竭的AMI患者,再灌注后随机分为洋地黄组(西地兰0.2 mg,n=17)和对照组(生理盐水20 m L,n=15)。在用药前、用药后30分钟、用药后3小时、用药后6小时、用药后12小时、用药后24小时进行5分钟HRV分析。结果:1洋地黄组的心率在用药6小时后显著小于对照组(P0.05);2洋地黄组SDNN在用药后3小时-6小时显著大于对照组(P0.05),两组RMSSD比较无显著统计学差别(P0.05);3洋地黄组LFnorm在用药后3小时-6小时显著大于对照组(P0.05);用药3小时后,洋地黄组HFnorm显著大于对照组(P0.05),LF/HF显著小于对照组(P0.05)。结论:小剂量洋地黄可以显著降低AMI PCI术后合并心力衰竭患者的心率、逆转迷走神经与交感神经活性的失衡状态,改善HRV。