糖尿病心血管自主神经功能检查法比较分析

目的 比较分析两种心血管功能检查法对糖尿病心血管自主神经病变(DCAN)的诊断价值.方法 对50例2型糖尿病患者进行心血管自主神经功能的检测:Ewing法和心率变异性(HRV)分析,对比两者DCAN检出率,并进行两种方法的相关分析.结果 Ewing法和HRV分析对DCAN的检出率分别为58%和42%(χ2= 65.51,P＞0.05);Ewing积分与LF/HF值的相关最密切(r=0.43,P＜0.01).结论 Ewing法和HRV分析存在相关关系;HRV分析不宜作为DCAN的常规筛选检查.     

2型糖尿病患者血清胱抑素C与低心率变异性的相关性研究

目的探讨T2DM患者血清胱抑素C(Cys-C)与心率变异性(HRV)的相关性。方法选取T2DM患者222例,根据Cys-C分为高Cys-C(n=112)和低Cys-C组(n=110)。免疫比浊法检测Cys-C,24h动态心电图评估HRV。结果高Cys-C组5min心搏间期均值的标准差(SDANN)低于低Cys-C组[109(89,136)vs 132(105,187)m/s,P0.05]。多元线性回归分析显示,Cys-C(log)与SDANN(log)(β=-0.395,P0.01)、低频/高频(LF/HF)(log)(β=-0.141,P0.01)、总功率TP(log)(β=-0.174,P0.01)独立相关。结论 T2DM患者血Cys-C与HRV指标(SDANN、LF/HF、TP)呈负相关,提示高Cys-C与糖尿病心脏自主神经病变(DCAN)相关。     

Ewing试验与心率变异性诊断糖尿病心血管自主神经病变的应用价值

目的探讨Ewing试验及心率变异性(HRV)诊断糖尿病心血管自主神经病变(CAN)的应用价值。方法选择我院内分泌科糖尿病档案管理数据库中的2型糖尿病病人114例为研究对象,所有受试者均接受Ewing试验和24 h动态心电图检查并分析HRV指标,分别采用Ewing试验积分法及Ewing试验联合HRV法诊断CAN。比较两种方法的结果差异。结果 Ewing试验结果:CAN阳性率为41.2%,CAN阳性组静息心率、Valsalva指数、深呼吸时每分钟心率差、立卧位心率变化评分明显高于阴性组,差异有统计学意义(P<0.05)。选取糖尿病病人人数较多的50～59岁及60～69岁年龄段,以Ewing试验为标准,分析CAN阳性组与阴性组HRV各指标,其中50～59岁病人,CAN阳性组与阴性组均方根值(rMSSD)、相邻R-R间期差异≥50 ms的百分数(PNN50)、低频功率(LF)比较,差异有统计学意义(P<0.05);60～69岁病人,CAN阳性组与阴性组rMSSD、总功率(TP)、LF比较,差异有统计学意义(P<0.05)。分析长时程HRV指标结果:存在异常病人34例,其中两项及以上异常病人20例。指标正常组与异常组Ewing评分比较,差异有统计学意义(P<0.05)。Ewing试验联合HRV法结果:CAN阳性率为37.7%,与Ewing试验积分法的总符合率为91.2%。结论 Ewing试验积分法与HRV法在诊断CAN时均有较高的检出率,两者符合率较高;2型糖尿病病人CAN以副交感神经功能损害为主;Ewing试验评分疑似阳性病人可进一步行HRV分析以减少漏诊。     

心率变异性参数对接受胰岛素治疗的2型糖尿病患者发生夜间无症状低血糖的预测价值

目的分析心率变异性(HRV)参数对接受胰岛素治疗的2型糖尿病(T2DM)患者发生夜间无症状低血糖的预测价值。方法选取2020年3月至2021年11月于扬州大学附属医院接受胰岛素治疗的T2DM患者207例。剔除夜间有症状低血糖患者19例,根据夜间低血糖发生情况将剩余患者分为夜间血糖正常组(137例)和夜间无症状低血糖组(51例)。比较两组患者基线资料、生化指标、HRV参数〔低频功率归一化值(LFnu)、高频功率归一化值(HFnu)、低频功率(LF)/高频功率(HF)、正常R-R间期的标准差(SDNN)、SDNN中每5 min R-R间期平均值的标准差(SDANN)、相邻R-R间期之差的均方根(RMSSD)、相邻R-R间期差值>50 ms的个数占总R-R间期个数的百分比(PNN50)〕。采用多因素Logistic回归分析探讨接受胰岛素治疗的T2DM患者发生夜间无症状低血糖的影响因素。采用ROC曲线分析HRV参数对接受胰岛素治疗的T2DM患者发生夜间无症状低血糖的预测价值。结果夜间无症状低血糖组患者空腹血糖、糖化血红蛋白低于夜间血糖正常组(P<0.05)。夜间无症状低血糖组患者HFnu、SDANN、RMSSD、PNN50低于夜间血糖正常组,LF/HF高于夜间血糖正常组(P<0.05)。多因素Logistic回归分析结果显示,HFnu、LF/HF、SDANN、RMSSD、PNN50是接受胰岛素治疗的T2DM患者发生夜间无症状低血糖的影响因素(P<0.05)。ROC曲线分析结果显示,HFnu、LF/HF、SDANN、RMSSD、PNN50预测接受胰岛素治疗的T2DM患者发生夜间无症状低血糖的AUC分别为0.768〔95%CI(0.680,0.856)〕、0.776〔95%CI(0.693,0.859)〕、0.769〔95%CI(0.693,0.845)〕、0.767〔95%CI(0.698,0.836)〕、0.770〔95%CI(0.695,0.844)〕,最佳截断值分别为38.38 Hz、1.91、52.31 ms、22.23 ms、6.14 ms,灵敏度分别为81.80%、74.50%、74.50%、70.80%、73.70%;特异度分别为66.70%、72.30%、72.50%、72.50%、74.50%。HFnu、LF/HF、SDANN、RMSSD、PNN50联合预测接受胰岛素治疗的T2DM患者发生夜间无症状低血糖的AUC为0.936〔95%CI(0.892,0.980)〕,灵敏度为70.60%,特异度为98.50%。HRV参数联合预测接受胰岛素治疗的T2DM患者发生夜间无症状低血糖的AUC分别大于HFnu、LF/HF、SDANN、RMSSD、PNN50单独预测接受胰岛素治疗的T2DM患者发生夜间无症状低血糖的AUC,差异有统计学意义(Z值分别为3.324、3.341、3.688、4.035、3.737,P值均<0.05)。结论HRV参数中的HFnu、LF/HF、SDANN、RMSSD、PNN50对接受胰岛素治疗的T2DM患者发生夜间无症状低血糖具有一定预测价值,而其联合预测的价值更高,其有望成为接受胰岛素治疗的T2DM患者发生夜间无症状低血糖的新型诊断标志物。     

2型糖尿病治疗前后心率变异性分析

目的：观察2型糖尿病（type 2 diabetes mellitus,T2DM）患者治疗前后心率变异性（heart rate variability,HRV）的变化。方法选取48例T2DM患者作为糖尿病组,另选取50例健康志愿者作为对照组。观察 T2DM患者治疗前后 HRV 时域指标 SDNN、SDANN、rMSSD、PNN50和HRV频域指标LF、HF、LF／HF、VLF的变化,并与对照组比较。结果糖尿病组治疗前HRV时域和频域指标均低于对照组（P＜0．05）;与治疗前相比,糖尿病组治疗后HRV时域指标SDNN、SDANN、rMSSD、PNN50和 HRV 频域指标 LF、HF、VLF 均有不同程度的改善（P＜0．05）。结论 T2 DM患者存在心脏自主神经调节功能异常,以迷走神经受损为主,治疗后自主神经调节功能有不同程度的恢复。     

高压氧辅助治疗2型糖尿病心脏自主神经病变的观察

将65例2型糖尿病(T2DM)合并DCAN患者,随机分成HBO治疗组35例,对照组30例,两组均给予常规药物治疗,治疗组加20次HBO治疗。治疗前后均测定心率、血压、血清钾和FPG及HbA1c,全部进行24小时动态心电图及心率变异性(HRV)分析。结果治疗组较对照组治疗前后心率、血压、血清钾和FPG及HbA1c比较差异无统计学意义(P0.05),而SDNN、SDANNr、MSSD、PNN50、LF、HF和LF/HF比较差异有统计学意义(P0.05)。结论高压氧治疗可以提高糖尿病患者心脏自主神经病变。     

老年糖尿病手术患者自主神经功能与无症状性心肌缺血的关系

目的探讨老年糖尿病(DM)患者手术前后心脏自主神经功能变化与无症状性心肌缺血(SMI)的关系。方法选择择期非心脏手术老年患者54例,其中非DM患者18例(NDM组),DM患者16例(DM组),DM合并SMI患者20例(SMI组)。监测3组患者心率变异性的变化,包括总功率(TP)、高频功率(HF)、低频功率(LF)、极低频功率(VLF)及LF/HF。结果与NDM组比较,DM组及SMI组术前TP、HF显著降低(P<0.05)。3组术后TP、HF、LF及VLF总的趋势是降低,其中SMI组下降最为明显。术后1天,SMI组TP、HF及VLF与术前比较明显降低,TP、HF、LF及VLF与NDM组差异明显(P<0.01,P<0.05),HF和VLF与DM组差异明显(P<0.05)。术后2天,除DM组LF外,3组TP、HF、LF及VLF分别与术前形成明显差异(P<0.05,P<0.01)。结论DM患者合并有心脏自主神经病变,手术应激引起机体自主神经调节心脏功能的进一步紊乱,是造成DM患者围手术期SMI高发的重要原因。     

2型糖尿病心脏自主神经病变与贫血相关性的研究

目的 探讨T2DM心脏自主神经病变（DCAN）与贫血的相关性。方法 选取2017年10月至2021年10月于重庆医科大学附属第一医院内分泌科住院治疗的T2DM患者1192例，根据Ewing试验分为单纯T2DM组（n=804）、早期DCAN组（n=234）和确诊DCAN组（n=154）。比较各组临床特征、血红蛋白（Hb）等。Spearman相关分析DCAN与其他指标的相关性，Logistic回归分析DCAN的影响因素。结果 与T2DM组比较，早期DCAN组、确诊DCAN组贫血占比升高，Hb降低（P<0.05）。Spearman相关分析显示，DCAN与Hb呈负相关（P<0.01）。Logistic回归分析显示，校正混杂因素后，贫血是DCAN的影响因素。结论 贫血与DCAN相关，是DCAN发生的危险因素。     

2型糖尿病患者非糖尿病后代心率变异性与血清脂联素水平的相关性研究

目的旨在探讨血清脂联素浓度降低是否与2型糖尿病(T2DM)患者非糖尿病后代心率变异性(heart rate variability,HRV)改变有关.方法31例(男16例,女15例)T2DM患者,所有子女(91例)排除已进行药物治疗的T2DM患者14例,其余空腹静脉取血测定血浆葡萄糖,排除≥7.0 mmol/L者3例,排除5.6~7.0 mmol/L之间者7例.选择其空腹血糖≤5.6 mmol/L后代行口服葡萄糖耐量试验,均未达到T2DM诊断标准,分为正常葡萄糖耐量组(NGT,n=32),葡萄糖耐量异常组(IGT,n=35),对照组(n=32)为无糖尿病家族史的健康查体者.行24 h动态心电图检查测定HRV,指标包括:全部正常窦性R-R间期值的标准差(SDNN);全程按5 min分成连续的时间段,先计算每5 min正常R-R间期的平均值,再计算所有平均值的标准差(SDANN);全部相邻R-R间期差的均方根(rMSSD);总功率(TP);低频功率(LF);高频功率(HF).ELISA法测定血清脂联素.结果T2DM非糖尿病后代血清脂联素水平与其体重指数(BMI)、空腹胰岛素负相关,与高密度脂蛋白胆固醇(HDL-c)、SDNN、SDANN、rMSSD、TP、LF、HF正相关.对照组、NGT组、IGT组之间血清脂联素逐渐降低、空腹胰岛素、SDNN、SDANN、rMSSD、TP、LF、HF逐渐升高.IGT组BMI、血清三酰甘油高于HDL-c,低于对照组和NGT组.结论自主神经平衡的改变与胰岛素抵抗和血清脂联素水平改变具有相关性.     

2型糖尿病心脏自主神经病变临床特征和危险因素分析

目的探讨2型糖尿病心脏自主神经病变(diabetic cardiac autonomic neuropathy,DCAN)的临床特征及相关危险因素。方法纳入2012年2月至2013年1月在广东省人民医院内分泌科就诊的2型糖尿病患者47例(按1999年世界卫生组织建议的糖尿病诊断标准),所有2型糖尿病患者进行葡萄糖耐量试验(OGTT)、胰岛素释放试验、血脂等分析,并以Ewing试验作为诊断DCAN的标准,对DCAN的患病情况、临床特征及可能的主要危险因素进行分析。同时,招募糖耐量正常者19例设为正常对照组。结果以Ewing试验为标准诊断心脏自主神经病变(cardiac autonomic neuropathy,CAN),正常对照组CAN的患病率仅为5.3%(1/19),2型糖尿病组为55.3%(26/47),两组比较差异有统计学意义(P=0.001)。2型糖尿病组中病程≤5年患者的DCAN患病率为45.2%(14/31),>5年患者为75.0%(12/16),两者比较差异有统计学意义(P=0.051)。2型糖尿病组中DCAN患者心率、收缩压、空腹胰岛素、胰岛素抵抗指数(HOMA-IR)、胰岛素分泌指数(HOMA-β)、尿酸与正常对照组患者比较,差异有统计学意义(P<0.05)。静息心率>80次/min、收缩压>140 mm Hg(1 mm Hg=0.133 kPa)、空腹胰岛素>100 pmol/L、胰岛素抵抗指数>5.3或胰岛素分泌指数>102.65、尿酸>350μmol/L的患者的DCAN患病率均较正明显增加,均差异有统计学意义(P<0.05)。Logistic回归分析显示,糖化血红蛋白(HbA1c)(OR=11.788)、胰岛素抵抗指数(OR=17.211)、尿酸(OR=5.757)是DCAN的主要独立危险因素。结论 2型糖尿病患者是CAN的高危人群;糖化血红蛋白、胰岛素抵抗指数、尿酸是DCAN的主要独立危险因素。     

Ewing试验及心率变异性对初诊2型糖尿病患者心血管自主神经病变诊断的比较

目的了解初诊2型糖尿病患者的心血管自主神经病变（CAN）患病情况及其特点,比较Ewing试验及心率变异性（HRV）两种常用评价方法对诊断CAN的差异。方法以2009年5月至2010年12月广东省4家医院（中山大学附属第三医院、汕头大学医学院第一附属医院、广东省人民医院、南方医科大学珠江医院）内分泌科收治的90例初诊2型糖尿病患者为糖尿病组,其中男58例,女32例,平均年龄（47±1）岁。以同期40名健康体检者为对照组,其中男21名,女19名,平均年龄为（45±2）岁。所有受试者均接受Ewing试验和24h动态心电图检查并分析HRV指标以诊断CAN,对比两种方法的结果差异。计量资料间比较采用t检验或单因素方差分析,等级资料采用秩和检验。结果（1）Ewing试验显示糖尿病组CAN阳性率[22．2％（20／90）]高于对照组[7．5％（3／40）,X2=4．12,P〈0．05];糖尿病组Ewing试验总评分（92．5分）高于对照组（7．0分,Z=-3．72,P〈0．01）,Ewing试验各指标（Valsalva指数、深呼吸心率差、立卧位心率变化及血压差）评分均较对照组升高,差异均有统计学意义（z值分别为-2．99、-2．23、-1．99、-2．36,均P〈0．05）。（2）HRV分析显示糖尿病组CAN阳性率[34．4％（31／90）]高于对照组[12．5％（5／40）,X2=6．66,P〈0．05];糖尿病组HRV中反映副交感神经功能的指标[全部正常窦性心搏问期（N—N）的标准差、连续5min正常R—R间期均值的标准差及低频功率]均降低,与对照组相比差异均有统计学意义（t值分别为2．06、2．24、6．48,均P〈0．05）,而代表交感神经功能的指标（全程相邻N．N间期之差的均方根值、相邻R—R间期差异≥50ms的百分数、高频功率）差异均无统计学意义（t值分别为0．27、0．15、1．40,均P〉0．05）。结论Ewing试验和HRV检测均显示初诊2型糖尿病患者中CAN阳性率较高,且以副交感神经损害为主;HRV检测较Ewing试验的CAN阳性率高。     

2型糖尿病患者心率震荡与自主神经功能损伤的关系

目的探讨2型糖尿病（T2DM）患者并发自主神经功能损伤与心率震荡现象（HRT）之间的关系。方法分为室速组，频发室早组，偶发室早组，对照组4组，分别做动态心电图检查，得出心率变异性（HRV）和心率震荡（HRT）的各项指标，对各组指标进行对比分析。结果偶发室早组、频发室早组、室速组患者TO明显高于对照组，TS，SDNN，LF，HF明显低于对照组（P〈0．05）；频发室早组、室速组患者TS值低于偶发组（p〈0．05）；在灵敏度、特异度方面，TO、TS高于SDNN，TS高于TO。结论糖尿病患者自主神经功能受损时，交感神经活性提高，迷走神经活性降低，心率震荡对其预测的灵敏度与特异度均高于心率变异性。     

Heart rate variability in white-coat hypertension

OBJECTIVES: The objective of this study was to compare heart rate variability (HRV) in patients with essential hypertension, in patients with white-coat hypertension and in normotensive control individuals, and to investigate a possible relation between HRV and vasoactive hormones. METHODS: Patients with essential hypertension (n=19, 61 years, median and interquartile range: 40-66 years), patients with white-coat hypertension (n=8, 52 years, median and interquartile range: 41-64 years) and normotensive participants (n=13, 50 years, median and interquartile range: 39-57 years) participated in the study. HRV was measured at rest in the supine position, during standing and during controlled forced breathing (respiration frequency >20/min). Power spectral density was calculated using Fourier transformation. RESULTS: Controlled breathing caused a decrease in low frequency (LF) variation and LF/high frequency variation (LF/HF) in all blood pressure groups. The decrease in LF was smaller in the hypertensive group (-60 ms2) than in the normotensive group (-139 ms2) (P=0.03; hypertensive group vs. normotensive group). The decrease in LF/HF induced by controlled breathing was -0.9 ms in the hypertensive group, -2.0 ms2 in the white-coat hypertensive group and -2.8 ms2 in the normotensive group, (P=0.037; hypertensive group vs. normotensive group). We found a positive correlation between baseline plasma renin concentration and LF (r=0.330, P=0.037) and LF/HF (r=0.378, P=0.016) at rest. CONCLUSION: The observed differences in HRV might reflect the impaired responsiveness to autonomic challenge in hypertensive patients. We did not find the HRV spectrum in white-coat hypertension different from the HRV spectrum in hypertension or normotension.     

Study of the autonomous nervous system with heart rate spectral analysis in acute myocardial infarction]

OBJECTIVES: Characterize power spectrum pattern of heart rate variability (HRV) and assessment of relative cardiac nervous system in patients with acute myocardial interaction of sympathetic and parasympathetic infarction. We also compared the spectral power with some known prognostic risk variables. STUDY DESIGN: Study of patients with acute myocardial infarction (AMI) and sedentary healthy subjects sex matched. SUBJECT AND METHODS: 19 postinfarction patients aged 55.7 +/- 10.5 years and 19 healthy subjects controls aged 53.9 +/- 11.0. ECG signals were recorded after 15 minutes of supine rest with controlled breathing at 15 cycles/min. Signal acquisition was done at 300 samples/sec. From 512 consecutive sinus beats, we calculated the average, standard deviation, maximum and minimum values and rate between the longest and shortest R-R interval (E/I). We also calculated, after computing the fast Fourier transform, the total spectrum power, low frequency component (LF, from 0.01 to 0.15 Hz), high frequency component (HF, from 0.15 to 0.50 Hz) and its ratio (LF/HF). Thereafter, we correlated these results with radionuclide ejection fraction, duration of treadmill test, Holter ventricular premature complex and localization of infarction. RESULTS: The average R-R interval was 757.9 +/- 116.3 and 850.9 +/- 133.9 msec (p less than 0.05), the R-R corrected standard deviation was 15.3 +/- 6.0 and 38.2 +/- 8.5 msec (p less than 0.001) and ratio E/I was 1.13 +/- 0.06 and 1.32 +/- 0.09 (p less than 0.001) in AMI and control group, respectively. In AMI group, low frequency spectral band was very decreased (LF = 0.03 +/- 0.02 sec2) and high frequency was virtually absent (HF = 0.01 +/- 0.01 sec2) compared with control group (LF = 0.13 +/- 0.06 and HF = 0.14 +/- 0.15 sec2), p less than 0.001; ratio LF/HF was increased in AMI group. There were no significant differences between groups for normalized LF (LF%) and HF (HF%). CONCLUSIONS: These results showed that spectral pattern in AMI patients had very low LF and HF power density. Decreased HRV in that group was mainly due to diminished parasympathetic influence in cardiac regulation; nevertheless ratio LF/HF was increased which represents an imbalance of sympatho-vagal activity with predominance of sympathetic tone. We found poor correlation between frequency domain indices and other risk variable; best correlation was between total spectral power and radionuclide ejection fraction (r = 0.642, p less than 0.01), which could express independent prognostic value in AMI patients risk stratification.     

Comparison of various methods of assessment of heart rate variability including simple cardiovascular reflex tests as predictors of sudden cardiac death after myocardial infarction.

Long term heart rate variability is used for prediction of sudden cardiac death (SD). There are simpler methods of assessment of autonomic cardiac control - registration of heart rate response to reflex tests and determination of heart rate variability (HRV) on short ECG recordins. Comparative value for prognosis of SD after myocardial infarction (MI) of these 3 techniques has not been studied yet. METHODS: Valsalva maneuver with calculation of Valsalva ratio (VR) and deep breath test with calculation of difference between average maximal and minimal HR during first minute of test (HR difference - HRD) were performed in 188 patients on days 4-11 of MI (68.1% men, age 34-75 years, 93.6% on beta-blockers, without heart failure NYHA IV on the day of tests). Time and frequency domain HRV measures were assessed during 15 min at bed rest and at Holter monitoring for median 24 h on the same day as reflex tests. RESULTS: During follow up for 2.1+/-0.8 years there were 9 sudden and 13 non-sudden cardiac deaths. ROC analysis was used to determine cut-off values of VR, HRD and HRV measures for dichotomization of patients into those with low- and high-risk of SD and these values were used in logistic regression analysis. The following parameters were univariate predictors of SD: obtained at reflex tests - VR <1.13 (OR 7.8, 95% CI 1.6-39.0; p=0.012), HRD <3.36 (OR 4.3, 95% CI 1.1-16.9; p=0.034); HRV parameters from 15 min ECG recordings - total frequency power <739 ms(2), VLF power <294 ms(2), LF power <197 ms(2) and LF/HF <1.5; HRV parameters from long term ECG recording - LF power <491 ms(2), LF/HF <1.4. At multivariate analysis only LF power for 15 min <197 ms(2) among HRV parameters remained independent predictor of SD (OR 24.2, 95% CI 2.4-245.5; p=0.007). Other predictors were clinical - VF during acute phase of MI (OR 94.7, 95% CI 4.2-2115.2; p=0.004) and history of MI (OR 8.4, 95% CI 1.4-48.5; p=0.017). CONCLUSION: In this population of patients without severe heart failure low LF power on 15 min resting ECG recordings on days 4-11 of MI was more powerful predictor of sudden cardiac death during subsequent 2 years than other HRV parameters including heart rate response to Valsalva maneuver and deep breath test.     

Effect of pioglitazone on cardiac sympathovagal modulation in patients with type 2 diabetes

This study aims to examine the effect of pioglitazone on potential progression of autonomic damage in addition to changes in control of cardiovascular function in patients with type 2 diabetes (T2DM). Thirty patients with T2DM and 32 healthy subjects participated in the study. Sympathovagal activity, assessed by power spectral analysis (PSA) of R–R intervals variability, and blood pressure (BP) were studied during clinostatism and orthostatism in controls and patients. We have assessed blood pressure control by 24-hour monitoring of ambulatory blood pressure. Patients were treated with pioglitazone (30 mg/day) for 6 months, and then re-evaluated by PSA for heart rate variability (HRV). Reduced levels of HbA1c (P < 0.0001) and urinary albumin (P = 0.008) were observed in pioglitazone-treated patients compared to untreated baseline levels. Arterial BP remained unchanged following pioglitazone treatment. T2DM patients had reduced HRV (low-frequency power; LF; P < 0.0001 and LF/HF; LF/HF; P < 0.0001) at baseline (clinostatism) compared to controls. Baseline clinostatic differences between groups persisted after pioglitazone treatment and no effect of treatment on basal HRV variables was observed. In controls, HF decreased and LF and LF/HF ratio increased in the orthostatic position. A similar effect for HF was observed in patients, but LF and LF/HF did not increase. The normal difference between HF-power in clinostatism versus orthostatism observed for controls (P < 0.0001) was restored in patients following pioglitazone treatment (P = 0.028). A significant decrease from lying to standing position in orthostatic LF-power (P < 0.0001) and LF/HF (P < 0.0001) was also observed between patients and controls. Although no differences in autonomic control of HRV were observed between controls and patients with T2DM, significant differences were observed in sympathovagal balance following either clinostatic or orthostatic challenge. These findings provide initial evidence of a potential additional benefit afforded by pioglitazone for the improvement of cardiac sympathovagal balance in T2DM.     

实验性心肌缺血大鼠心脏自主神经活性的动态变化及意义

采用心率变异（ＨＲＶ）时域及频域指标分析急性心肌缺血２４ｈ大鼠心脏自主神经功能的变化以探讨其意义。将实验动物分成三组，即正常对照组（２０只）、假手术组（２０只）与心肌缺血组（４８只），并运用动态心电图记录２４ｈ心电信号变化。结果显示：与假手术组及正常对照组分别比较，心肌缺血组正常窦性心律ＲＲ间期标准差（ＳＤＮＮ）下降（２８．９±９．４ｍｓｖｓ３４．４±１３．７ｍｓ或３５．１±１４．３ｍｓ，Ｐ均＜０．０５），低频（ＬＦ）及低频与高频的比值（ＬＦ／ＨＦ）明显增加（１８９．４±３６．５ｍｓ２／Ｈｚｖｓ５７．３±１７．８ｍｓ２／Ｈｚ或５１．８±１８．６ｍｓ２／Ｈｚ；３．８５±０．９１ｖｓ１．７６±０．６３或１．６８±０．５７，Ｐ均＜０．０１）；２４ｈ心率功率谱示心肌缺血组ＬＦ及ＬＦ／ＨＦ波动幅度较假手术组及正常对照组增高，缺血大鼠ＬＦ与ＬＦ／ＨＦ在缺血后０～３ｈ（２６７．５±１２．４ｍｓ２／Ｈｚ、４．３３±１．０８）及９～１２ｈ（２４４．７±１３．９ｍｓ２／Ｈｚ、３．９６±０．９８）期间增高显著，而在缺血后５～７ｈ（１４９．２±８．７ｍｓ２／Ｈｚ、２．０５±０．４２）内则相对较低。结果表明大鼠心肌缺血后ＨＲＶ降低主?