依托咪酯或丙泊酚对老年冠心病非心脏手术围插管期心率变异性的影响

目的 研究依托咪酯和丙泊酚对老年冠心病患者行非心脏手术时在全身麻醉诱导气管插管期间心率变异性(HRV)的影响.方法将90例择期行中上腹部手术的老年冠心病患者随机分成依托咪酯组(E组)和丙泊酚组(P组),每组各45例.分别于麻醉前、麻醉诱导后及气管插管后用心率变异功率谱分析技术观察两组患者的HRV变化.结果麻醉诱导后,E组总功率(TP)和HRV低频(LF)[(756±535)ms2/Hz和(316±301)ms2/Hz],P组LF、HRV高频(HF)、LF/HF及TP[(187±168)ms2/Hz、(89±48)ms2/Hz、2.3±1.6和(616±462)ms2/Hz]均较麻醉前显著降低(P<0.05);组间比较,麻醉诱导后,E组LF、HF、LF/HF及TP均显著高于P组(P<0.05).气管插管后,两组LF、HF、LF/HF及TP均较麻醉前显著升高(P<0.05);组间比较,气管插管后两组HRV各指标比较差异均无统计学意义(P>0.05).结论丙泊酚在麻醉诱导时对老年冠心病自主神经功能的抑制作用强于依托咪酯;而对于气管插管引起的心血管反应而言依托咪酯和丙泊酚药效相似.     

以心率和心率变异性为指标的疲劳分析系统

从心电信号中提取心率(HR)和心率变异性(HRV),并对其5项时频域指标进行分析。实验结果发现:疲劳后,HRV时域测量指标中的正常R-R间期的标准差(SDNN)明显上升,HRV频域测量指标中的总功率值TP明显上升,低频段功率值LF明显上升,高频段功率值HF明显下降,LF与HF的比值LF/HF明显上升。并根据其上升与下降的速率的不同划分疲劳等级。因而,采用此5项心电图时频域指标,可以对疲劳程度进行定量化的反映和评价。     

晕船病与心率变异性的关系

目的分析心率变异性(heart rate variability,HRV)与晕船病的关系,探索预测晕船病易感性的生理指标。方法采集58名健康受试者陆上安静状态下和海上航行中的的短程心率变异指标,根据航海中是否出现晕船反应分为晕船病组26人和不晕船对照组32人。应用心率变异性时域、频域分析方法,分别评价其自主神经功能状态。结果海上航行中,晕船病组心率变异性时域指标明显高于对照组:RR间期平均值(MRR)增高21.26%,RR间期平均值的标准差(SDNN)增高27.75%,相邻RR间期差值的标准差(rMSSD)增高18.42%,相邻RR间期相差大于50ms占总心动周期的百分比(PNN50)增高32.14%,心率变异性指数(HRVI)增加24.05%。心率变异频域指标中,晕船病组与对照组比较,低频带(LF)增高81.98%,高频带(HF)增高13.59%,总功率谱密度(TP)增加32.43%,LF与HF比值(LF/HF)降低31.82%。在陆地上安静状态下,晕船病组心率变异性指标与对照组比较:SDNN、PNN50、HRVI分别增加26.68%、30.32%、30.48%,VLF、LF、HF、TP分别增加31.82%、45.05%、41.98%、37.62%;LF/HF降低32.43%。结论自主神经功能在运动病的发生中起着重要作用。晕船病者固有的自主神经张力较高,而且在发生晕船病时自主神经张力明显增高,特别是以迷走神经张力为主。心率变异性检测可以作为预测晕船病易感性的一个重要指标。     

小剂量倍他乐克对应急训练心率变异的影响

目的观察服用小剂量倍他乐克对部队战士应急训练 (5km越野 )过程中心率变异的影响 ,评价小剂量倍他乐克对运动过程中心血管自主神经的调节作用。方法 80名 18～ 2 2岁男性战士 ,随机分为倍他乐克组 (倍他乐克 6 .2 5mg·次 1,每日 2次 ,共 1周 )和对照组 (安慰剂 )。测量受试者运动前后血糖、血乳酸及血浆儿茶酚胺 (E、NE)的浓度 ;采用Holter记录运动前 10min ,运动中 30min及运动后 2 0min的心电信号 ,进行心率变异 (HRV)分析。结果应急训练可显著升高血糖、血乳酸 ,但服用倍他乐克和安慰剂后 ,两组均无显著差异 ;运动使血浆E和NE显著升高(P <0 .0 1) ,对照组NE较倍他乐克组升高更显著 (P <0 .0 5 )。两组在运动中低频峰 (LF)均升高 ,高频峰 (HF)下降 ,LF/HF升高。对照组LF较倍他乐克组升高更为显著〔(191.4± 30 .8)(b·min 1) 2 /Hz　vs .(16 9.8± 32 .7) (b·min 1) 2 /Hz ,P <0 .0 5〕 ,而HF下降更显著〔(34.4± 11.4 )(b·min 1) 2 /Hzvs .(5 7.2± 12 .4 ) (b·min 1) 2 /Hz ,P <0 .0 5〕。结论应急训练使心脏交感神经兴奋 ,迷走神经抑制 ,心率变异性降低 ;小剂量倍他乐克可提高应急训练时的心率变异性 ,使心脏交感神经和迷走神经的平衡调节改善     

中年人群短时心率变异性分析

目的探讨中年人群心率变异性(HRV)特征,分析其自主神经活性及功能、疲劳度和心理压力的大小,比较不同时期中年人心率变异性差异。方法收集2016年1—12月体检中心进行心率变异性分析的中年人共837例,采用5 min短时心率变异分析仪记录HRV的各项指标。计量资料组间比较采用单因素方差分析,两两比较采用SNK-q检验,计数资料比较采用χ~2检验,HRV相关因素分析采用多重线性回归,P0.05为差异有统计学意义。结果不同时期中年人SDNN、TP、LF、LF/HF比较差异有统计学意义(均P0.05),HF比较差异无统计学意义(P0.05)。调整期窦性心博间期标准差(SDNN)和点功率(TP)较低,壮实期低频功率(LF)和平衡度(LF/HF)较高;疲劳度随年龄增加而增大,心理压力在壮实期最高,自主神经活性和功能在调整期最低。多重线性回归分析结果显示,年龄、疲劳度、心理压力、平均心率对该人群HRV各项指标的影响具有统计学意义(均P0.05)。结论随着年龄的增长,中年人群疲劳度增高,自主神经活性及功能降低,壮实期中年人群心理压力最高。     

阻塞性睡眠呼吸紊乱综合征有效治疗前后的心率变异性分析

目的通过观察OSAS患者经过有效治疗前后HRV的变化,评价患者的心率变异性变化情况。方法对51例OSAS病人在有效治疗前后同步进行PSG检查及动态心电监测,统计其HRV的时阈指标SDNN、rMSSD及频阈指标LF、HF及LF/HF,采用SPSS/PC统计软件中配对样本t检验进行处理。结果SDNN、LF、LF/HF等指标在治疗前后的差异有显著性(p<0·05),rMSSD、HF的变化无显著性差异(p>0·05)。结论有效治疗OSAS可使植物神经系统的功能得到恢复,降低心脏事件发生的危险性。     

外周神经阻滞时术中镇静对老年患者心率变异性的影响

目的 观察靶控输注咪达唑仑和普鲁泊福镇静时老年患者心率变异性(HRV)的变化.方法 选择在外周神经阻滞下行四肢手术的老年患者30例,按随机数字表法分为普鲁泊福组和咪达唑仑组,每组15例.比较两组的平均动脉压(MAP)、心率及HRV指标.结果 普鲁泊福组意识恢复时间[(6.3±1.3)min]明显短于咪达唑仑组[(15.4±3.1)min](P＜0.05).随着镇静程度的加深,咪达唑仑组低频成分(LF)、LF标准化值(nuLF)、LF/高频成分(HF)、总功率(TP)和MAP逐渐降低,HF标准化值(nuHF)逐渐升高.普鲁泊福组中HF、LF、nuHF、nuLF和TP随着镇静程度的加深明显降低,尤以HF降低为明显,LF/HF有上升趋势.结论 咪达唑仑主要抑制交感神经活性,而普鲁泊福主要抑制副交感神经活性.     

扩张型心肌病自主神经功能及昼夜变化

目的 研究扩张型心肌病(DCM)自主神经功能及昼夜变化。方法 采用临床病例对照,DCM组31例与正常人31例根据性别、年龄配对,运用动态心电图和计算机数据处理技术,结合心率变异(HRV)长时程时域分析与昼夜6个时点频域分析,观察平均心动周期、24小时全部正常心动周期的标准差(SDNN)、低频(LF)与高频(HF)功率、LF/HF比值等指标的变化。结果 (1)DCM患者24小时平均心动周期较对照组短,昼夜平均心动周期差减小(P<0.01);DCM组SDNN为93.78±45.06ms,正常人149.72±31.32ms,差异有显著意义(P<0.01)。(2)DCM组患者各时点的LF、HF均较对照组降低。对照组白天LF明显高于HF,DCM组LF稍高于HF,但LF/HF值升高;对照组夜间HF高于LF,但DCM组LF高于HF,LF/HF值升高。结论 DCM患者自主神经功能受损,交感神经及迷走神经活性降低,昼夜节律异常,交感-迷走神经功能平衡失调。夜间交感神经功能相对亢进,可能是夜间恶性心律失常及猝死的原因。     

卡维地洛对慢性充血性心力衰竭患者心功能及心率变异性的影响

目的　观察卡维地洛对慢性充血性心力衰竭 (CHF)患者心功能和心率变异性 (HRV)的影响。方法　 63例CHF患者随机分为两组 ,在心衰常规用药的基础上 ,卡维地洛由小剂量开始 ,逐渐递增至目标剂量。治疗前及治疗 6月后测定心功能及HRV指标。结果　治疗 6月后卡维地洛组与对照组比较 ,左室舒张末期内径 (LVEDD)、左室收缩末期内径 (LVESD)显著下降 (P <0 0 5 ) ,左室射血分数 (LVEF)显著增加 (P <0 0 5 ) ;心率变异性指标全部窦性心律R -R间期的标准差 (SDNN) ,全程连续 5minR -R间期标准差的平均值 (SDANN) ,全部相邻R -R间期差值的均方根 (rMSSD) ,相邻RR间期差值 >5 0ms的百分比 (PNN5 0 ) ,低频率段功率 ( 0 0 4～ 0 15Hz) (LF) ,高频率段功率 ( 0 15～ 0 40Hz) (HF)显著增加 ( P <0 0 5 ) ,LF/HF比值显著下降 ( P <0 0 5 )。结论　卡维地洛加心衰常规治疗 ,在改善CHF患者心功能的同时显著改善HRV ,从而改善自主神经的平衡性 ,改善患者的预后     

有或无心脏症状的更年期女性心率变异分析

目的:探讨更年期女性有或无心脏症状与心率变异性(HRV)的关系。方法:96例更年期女性按照有无心脏症状分为无症状组(46例)和有症状组(50例),应用24 h动态心电图对两组患者进行HRV的对比分析。结果:有症状组SDNN、SDNN Index、rMSSD、PNN50、TP、LF及HF较无症状组明显降低(P<0.01),LF/HF比值增高(P<0.01)。结论:更年期女性有心脏症状者HRV降低,表现为交感神经张力增高,迷走神经张力降低,两者协调作用失衡。     

Opuntia ficus indica's effect on heart-rate variability in high-level athletes

Opuntia ficus indica (OFI) has many physiological effects, but a relationship between OFI and heart-rate variability (HRV) has never been established. The aim of this study was to describe the effects of a diet supplement of OFI on HRV in athletes. The first day, heart rate (HR) was measured at rest in supine (SU) and standing (ST) positions to analyze HRV in 10 athletes, followed by a randomized assignment to an OFI (5) or placebo (5) group. The next day, the athletes repeated the HRV test. One month later the crossover protocol was applied. In OFI, the high-frequency-activity HF(SU) (1,773 +/- 2,927 vs. 5,856 +/- 8,326 ms(2), p < .05), HF(ST) (295 +/- 313 vs. 560 +/- 515 ms(2), p < .05), and low-frequency LF(SU) (1,621 +/- 1,795 vs. 6,029 +/- 9,007 ms(2), p < .01) increased. HR(SU) (66 +/- 13 vs. 57 +/- 11 beats/min, p < .01) and HR(ST) (87 +/- 11 vs. 76 +/- 9 beats/min, p < .01) decreased. A diet supplement of OFI increases HF and LF activities and decreases HR.     

甲状腺功能亢进症患者植物神经功能的昼夜周期改变

目的 研究甲状腺功能亢进症(甲亢)患者植物神经功能的昼夜周期改变.方法 记录33例初发甲亢患者(甲亢组)和35例健康体检者(对照组)的24 h动态心电图,并通过心率变异性的时域和频域分析来评价心脏植物神经功能状态.结果 甲亢组所有NN间期的标准差(SDNN);以5 min为间隔将24 h连续记录分为288段,先计算每段的平均NN间期,然后计算288个NN间期平均值的标准差(SDANN);以5 min为间隔将24 h连续记录分为288段,先计算每段的NN间期标准差,然后计算288个NN间期标准差的平均值(ASDNN);所有相邻NN间期差值的均方根(rMSSD)显著低于对照组[(82.3±29.0)ms比(139.4±40.2)ms;(75.0±27.4)ms比(130.3±43.9)ms;(29.9±14.9)ms比(57.3±14.4)ms;(19.8±10.9)ms比(29.5±9.4)ms](P＜0.01或＜0.05).甲亢组总功率(TP)、高频功率(HF)、低频功率(LF)和极低频功率(VLF)显著低于对照组[(566.1±573.2)ms2/Hz比(1894.2±984.3)ms2/Hz、(68.1±88.9)ms2/Hz比(232.7±155.5)ms2/Hz、(127.4±163.0)ms2/Hz比(551.3±390.6)ms2/Hz、(330.3±300.6)ms2/Hz比(1073.2±570.2)ms2/Hz](P＜0.01).短时频域分析甲亢组VLF在全天大多数时间均显著高于对照组(P＜0.05),LF主要在白天显著高于对照组(P＜0.05),HF在全天散在时间高于对照组(P＜0.05);两组LF/HF在全天绝大多数时间差异无统计学意义(P＞0.05).结论 甲亢患者心脏变时性低,交感神经张力在全天均增高,而迷走神经张力虽有相应增高,但以白天增高为主,夜间接近正常水平.

Abstract：

Objective To investigate the circadian change of autonomic nervous system in hyperthyroidism (HT) patients. Methods Recording 24 h dynamic electrocardiography from 33 HT patients( HT group) and 35 controls (control group). The cardiac autonomic nervous function was evaluated by the time domain and frequency domain analysis of heart rate variability( HRV). Results Comparing with control group, the SDNN, SDANN, ASDNN and rMSSD were significantly lower in HT group[ (82.3 ± 29.0)ms vs. (139.4±40.2 ) ms, ( 75.0 ± 27.4) ms vs. ( 130.3 ± 43.9) ms, (29.9 ± 14.9 ) ms vs. (57.3 ± 14.4) ms,( 19.8 ± 10.9 ) ms vs. (29.5 ± 9.4) ms ] (P ＜ 0.01 or ＜ 0.05 ), the long term total power (TP), high frequency (HF), low frequency (LF) and very low frequency (VLF) were significantly lower in HT group [ (566.1±573.2) ms2/Hz vs. ( 1894.2 ± 984.3)ms2/Hz, (68.1 ± 88.9 ) ms2/Hz vs. (232.7 ± 155.5 ) ms2/Hz, ( 127.4 ±163.0) ms2/Hz vs. (551.3 ± 390.6) ms2/Hz, (330.3 ± 300.6) ms2/Hz vs. (1073.2 ± 570.2) ms2/Hz] (P ＜0.01 ). Comparing with control group, short term VLF was higher in HT group during most time in 24 hours (P＜ 0.05 ). Short term LF was higher in HT group mainly in day time (P＜ 0.05 ). Short term HF was higher in HT group occasionally in the whole day (P＜0.05). Short term LF/HF didn't show significant difference between HT group and control group at most time points (P＞0.05).Conclusion In HT patients, cardiac chronotropic property is impaired, sympathetic activity increases in whole day, vagal activity increases correspondently but the increase in day is more marked than that in night.     

The influence of the call with a mobile phone on heart rate variability parameters in healthy volunteers

It is possible that electromagnetic field (EMF) generated by mobile phones (MP) may have an influence on the autonomic nervous system (ANS) and modulates the function of circulatory system. The aim of the study was to estimate the influence of the call with a mobile phone on heart rate variability (HRV) in young healthy people. The time and frequency domain HRV analyses were performed to assess the changes in sympathovagal balance in a group of 32 healthy students with normal electrocardiogram (ECG) and echocardiogram at rest. The frequency domain variables were computed: ultra low frequency (ULF) power, very low frequency (VLF) power, low frequency (LF) power, high frequency (HF) power and LF/HF ratio was determined. ECG Holter monitoring was recorded in standardized conditions: from 08:00 to 09:00 in the morning in a sitting position, within 20 min periods: before the telephone call (period I), during the call with use of mobile phone (period II), and after the telephone call (period III). During 20 min call with a mobile phone time domain parameters such as standard deviation of all normal sinus RR intervals (SDNN [ms]--period I: 73.94+/-25.02, period II: 91.63+/-35.99, period III: 75.06+/-27.62; I-II: p<0.05, II-III: p<0.05) and standard deviation of the averaged normal sinus RR intervals for all 5-mm segments (SDANN [ms]--period I: 47.78+/-22.69, period II: 60.72+/-27.55, period III: 47.12+/-23.21; I-II: p<0.05, II-III: p<0.05) were significantly increased. As well as very low frequency (VLF [ms2]--period I: 456.62+/-214.13, period II: 566.84+/-216.99, period III: 477.43+/-203.94; I-II: p<0.05), low frequency (LF [ms(2)]--period I: 607.97+/-201.33, period II: 758.28+/-307.90, period III: 627.09+/-220.33; I-II: p<0.01, II-III: p<0.05) and high frequency (HF [ms(2)]--period I: 538.44+/-290.63, period II: 730.31+/-445.78, period III: 590.94+/-301.64; I-II: p<0.05) components were the highest and the LF/HF ratio (period I: 1.48+/-0.38, period II: 1.16+/-0.35, period III: 1.46+/-0.40; I-II: p<0.05, II-III: p<0.05) was the lowest during a call with a mobile phone. The tone of the parasympathetic system measured indirectly by analysis of heart rate variability was increased while sympathetic tone was lowered during the call with use of a mobile phone. It was shown that the call with a mobile phone may change the autonomic balance in healthy subjects. Changes in heart rate variability during the call with a mobile phone could be affected by electromagnetic field but the influence of speaking cannot be excluded.     

依托咪酯或丙泊酚对老年冠心病非心脏手术围插管期心率变异性的影响

目的研究依托咪酯和丙泊酚对老年冠心病患者行非心脏手术时在全身麻醉诱导气管插管期间心率变异性（HRV）的影响。方法将90例择期行中上腹部手术的老年冠心病患者随机分成依托咪酯组（E组）和丙泊酚组（P组）,每组各45例。分别于麻醉前、麻醉诱导后及气管插管后用心率变异功率谱分析技术观察两组患者的HRV变化。结果麻醉诱导后,E组总功率（11P）和HRV低频（LF）[（756±535）ms^2／Hz和（316±301）ms^2／Hz],P组LF、HRV高频（HF）、LF／HF及TP[（187±168）ms^2]Hz、（89±48）ms^2／Hz、2．3±1．6和（616±462）ms^2／Hz]均较麻醉前显著降低（P〈0．05）;组间比较,麻醉诱导后,E组LF、HF、LF／HF及11P均显著高于P组（p〈0．05）。气管插管后,两组LF、HF、LF／HF及11P均较麻醉前显著升高（P〈0．05）;组间比较,气管插管后两组HRV各指标比较差异均无统计学意义（P〉0．05）。结论丙泊酚在麻醉诱导时对老年冠心病自主神经功能的抑制作用强于依托咪酯;而对于气管插管引起的心血管反应而言依托咪酯和丙泊酚药效相似。     

Autonomic nervous system activity and the state and development of obesity in Japanese school children

OBJECTIVE: The autonomic nervous system (ANS) plays an important role in regulating energy expenditure and body fat content; however, the extent to which the ANS contributes to pediatric obesity remains inconclusive. The aim of this study was to evaluate whether sympathetic and/or the parasympathetic nerve activities were altered in an obese pediatric population. We further examined a physiological association between the duration of obesity and the sympatho-vagal activities to scrutinize the nature of ANS alteration as a possible etiologic factor of childhood obesity. RESEARCH METHODS AND PROCEDURES: Forty-two obese and 42 non-obese healthy sedentary school children were carefully selected from 1080 participants initially recruited to this study. The two groups were matched in age, gender, and height. The clinical records of physical characteristics and development of the obese children were retrospectively reviewed to investigate the onset and progression of obesity. The ANS activities were assessed during a resting condition by means of heart rate variability power spectral analysis, which enables us to identify separate frequency components, i.e., total power (TP), low-frequency (LF) power, and high-frequency (HF) power. The spectral powers were then logarithmically transformed for statistical testing. RESULTS: The obese children demonstrated a significantly lower TP (6.77 +/- 0.12 vs. 7.11 +/- 0.04 ln ms(2), p < 0.05), LF power (6.16 +/- 0.12 vs. 6.42 +/- 0.05 ln ms(2), p < 0.05), and HF power (5.84 +/- 0.15 vs. 6.34 +/- 0.07 ln ms(2), p < 0.01) compared with the non-obese children. A partial correlation analysis revealed that the LF and HF powers among 42 obese children were negatively associated with the duration of obesity independent of age (LF: partial r = -0.55, p < 0.001; HF: partial r = -0.40, p < 0.01). The obese children were further subdivided into two groups based on the length of their obesity. All three spectral powers were significantly reduced in the obese group with obesity of >3 years (n = 18) compared to the group with obesity of <3 years. DISCUSSION: Our data indicate that obese children possess reduced sympathetic as well as parasympathetic nerve activities. Such autonomic depression, which is associated with the duration of obesity, could be a physiological factor promoting the state and development of obesity. These findings further imply that preventing and treating obesity beginning in the childhood years could be an urgent and crucial pediatric public health issue.     

Heart rate variability and left ventricular diastolic function in anorexia nervosa

PURPOSE: To investigate the cardiac effects of starvation in a group of adolescents with anorexia nervosa (AN). METHODS: Twenty-five patients with AN (range 13-20 years), compared with 25 age-matched thin and 25 age-matched control women with body mass index > 20 Kg/m(2), underwent a complete clinical evaluation, including echocardiogram and 24-hour electrocardiogram monitoring to evaluate heart rate variability (HRV) indices. RESULTS: Compared to both thin and control women, patients with AN had greater HRV time domain indices (SDNN: 246.5 +/- 32.4 vs. 170.4 +/- 24 ms and vs. 181 +/- 21.2 ms, p <.001), and in the frequency domain a lower LF/HF ratio (4.2 +/- 1.3 vs. 6.7 +/- 1.2 and vs. 6.8 +/- 1.3 ms, p <.001). AN patients showed reduced left ventricular mass with normal systolic function and typical diastolic patterns, characterized by a lower peak velocity transmitral flow in late diastole (peak A: 35.9 +/- 8.5 vs. 45.2 +/- 7.3 cm/sec and vs. 46.6 +/- 6.3 cm/sec, p <.01), a comparable peak velocity in early diastole (peak E: 92.7 +/- 12.1 vs. 83 +/- 6.2 and vs. 86.8 +/- 9.1 cm/sec, ns) and, subsequently, a greater E/A ratio (2.8 +/- 0.7 vs. 1.8 +/- 0.3 and vs. 1.9 +/- .5, p <.01) than thinness and control groups. Moreover, SDNN was also positively related to E/A ratio (r =.54, p <.01). CONCLUSIONS: Our findings demonstrate a cardiovascular vagal hyperactivity in AN, which appears to influence the ventricular diastolic dynamics. HRV and diastolic function analysis may represent useful tools in monitoring anorexia-induced cardiac modifications.     

视觉显示终端心算作业脑力负荷的评价

目的探讨用主观评分法、主任务评定法、心理生理学评定法3种脑力负荷评定方法来评价视觉显示终端（WT）心算作业时脑力负荷的可行性。方法记录分析了受试者完成3种不同难度心算时的Cooper-Harper量表评分、正确率、做题速度、心率变异性、瞳孔直径、眨眼率等脑力负荷评定指标。结果随着心算算式变数位数的增加，3组心算的Cooper-Harper量表评分分值逐渐增加；心算的正确率逐渐下降；做题的速度逐渐减慢；瞳孔直径逐渐增大；眨眼率逐渐减少。与休息时相比，心算时心率变异性（HRV）的总的频域值（TP）、极低频成分（VLF）、低频成分（LF）、低频的归一化值（LFnorm）、低频／高频比率（LF／HF）值降低，高频的归一化值（HFnorm）、HF／TP、相邻RR间期差的均方根（rMSSD）值增大，但3组心算之间的差异无统计学意义（P〉0．05）。结论随着心算算式变数位数的增加，受试者脑力负荷增加。3种脑力负荷评定方法均能在一定程度上反映不同难度心算任务的脑力负荷信息，联合应用多种指标评定脑力负荷更为可行。     

右美托咪定镇静对老年白内障手术患者围手术期血流动力学与心率变异性的影响

目的 探讨右美托咪定镇静对老年白内障手术患者围手术期血流动力学与心率变异性（HRV）的影响.方法 选择老年白内障患者50例,择期于局部麻醉下行超声乳化手术,按随机数字表法分为试验组和对照组,每组25例.试验组在静脉给予右美托咪定负荷量0.5μg/kg后局部麻醉,术中持续泵注右美托咪定[0.2～0.3μg/（kg·h）]维持麻醉深度.对照组静脉给予同等剂量的0.9％氯化钠后局部麻醉.局部麻醉方法：2％利多卡因及0.75％布比卡因各3ml等量混合行球后阻滞麻醉.记录两组术前（T0）、开始手术（T1）、术中10 min（T2）、术中30 min（T3）、术毕（T4）的HRV变化,并对血流动力学进行分析.结果 对照组T1、T2、T3低频（LF）标准化值（LFnu）、LF与高频（HF）比值（LF/HF）均高于T0[（73.9±9.2）％、（74.5±9.0）％、（75.8±8.5）％比（61.3±7.5）％和2.4±1.1、2.6±1.3、2.7±0.9比1.6±0.5],总频（TP）均低于T0[（1372±419）、（915±243）、（1389±142） Hz比（2351±608） Hz],差异有统计学意义（P＜0.05）.试验组T1、T2、T3 LFnu、LF/HF均较T0有所升高,但差异无统计学意义（P＞ 0.05）,试验组T1、T2、LTP均低于T0[（1458±325）、（983±272）、（1497±210） Hz比（2235±513）Hz],差异有统计学意义（P＜0.05）.两组各时间点HF标准化值比较差异无统计学意义（P＞0.05）.试验组T1、T2、T3 LFnu、LF/HF、TP均优于同期对照组,差异有统计学意义（P＜0.05）.试验组的血流动力学波动要小于对照组,差异有统计学意义（P＜0.05）.结论 右美托咪定镇静对老年白内障手术患者围手术期的HRV影响较小,可显著降低手术刺激对自主神经系统与血流动力学的影响.     

Effects of capsaicin-containing yellow curry sauce on sympathetic nervous system activity and diet-induced thermogenesis in lean and obese young women

The present study was designed to investigate the effect of capsaicin, a pungent component of red pepper, on the sympathetic nervous system (SNS) activity and energy metabolism in 16 age- and height-matched lean and obese young women. The sympatho-vagal activities were assessed by means of spectral analysis of heart rate variability (HRV) during the resting condition and after the meal (2,016 kJ) with capsaicin (3 mg). Energy expenditure was also measured under the two conditions. There was no significant difference in any of the parameters of the HRV between the obese and control groups at rest. After the capsaicin diet, however, the very low frequency component (0.007-0.035 Hz) associated with thermogenesis (315.8+/-78.0 vs. 814.8+/-211.7 ms2 x Hz(-1), p<0.05) as well as its responsiveness (delta changes: 14.6+/-104.4 vs. 369.2+/-121.7 ms2 x Hz(-1), p<0.05) were significantly lower in the obese than the control group. Energy expenditure was significantly increased in the control group after the meal (5,574.7+/-221.2 to 6,114.7+/-239.0 kJ day(-1); p<0.01), but no such significant thermogenic response was detected in the obese group despite nearly identical lean body mass of the control group. Our data indicate that regardless of the resting level of sympatho-vagal activities, the reduced sympathetic responsiveness to physiological perturbation such as a capsaicin diet, which may cause impaired diet-induced thermogenesis and further weight gain, could be an important etiological factor leading to obesity in young women.