Circadian pattern of heart rate variability in chronic heart failure patients Effects of physical training

The effect of physical training on the circadian pattern ofheart rate variability (recorded over 24 h in relation to bothtime and frequency) was assessed in 12 chronic heart failurepatients randomized, in a cross-over design, to 8 weeks trainingor detraining, and compared with 12 age-matched normals. Trainingimproved heart rate variability indices: all R-R interval 5min standard deviations increased by 17.6%, the root mean squareof the differences of successive R-R intervals by 34.9%, thepercentage difference between adjacent normal RR intervals>50ms by 112.5%, total power by 58.3%, high frequency by 128.5%and low frequency by 65.0%. Compared with controls, circadianvariations in autonomic parameters were maintained in chronicheart failure. Training-induced changes were observed at differenttime intervals throughout the day: the highest values were at0100 h-0700 h (detraining: low frequency 361±83 ms²,high frequency 126±47 ms²; training: low frequency 535±202ms², high frequency 227±115 ms², P<0.01) and the lowestat 1300 h-1900 h (detraining: low frequency 91±23 ms²,high frequency 39±14 ms²; training: low frequency 154±42ms², high frequency 133±67 ms², P<0.05). In chronicheart failure, training maintains and improves circadian variationsin heart rate variability measures.     

慢性肾衰血液透析患者心率变异性及其影响因素分析

目的 :分析慢性血液透析患者的心率变异性 （HRV）及其影响因素。方法 :观察了 80例接受慢性血液透析治疗的患者。血液透析开始前记录 2 4h动态心电图 ,采用 R- R间期的标准差 （SDNN）作为 HRV的指标。采用多元回归法 ,对年龄、性别、透析前体重指数、缺血性心肌病、糖尿病肾病、吸烟、累积进行血液透析的时间、透析前平均血压、血细胞比容 （Hct）、血浆尿素氮水平 （BU N）、转换酶抑制剂 （ACEI）和β-受体阻滞剂的使用等 12个可能影响 SDNN的独立因素进行了分析。结果 :老年 （P<0 .0 1） ,原发病为糖尿病肾病 （P<0 .0 1） ,Hct降低 （P=0 .0 12 2 ） ,透析前体重指数增加 （P=0 .0 132 ） ,长期进行血透的患者 （P=0 .0 2 0 1）及吸烟者 （P=0 .0 34 5 ）与 SDNN的降低呈明显的相关性。结论 :除已证明的因素外 ,慢性血液透析患者的肾性贫血、透析前体重指数及累计进行血液透析的时间也是患者心率变异性的独立影响因素     

体育锻炼对正常男性心率变异性的影响

目的:探讨长期体育锻炼对男性自主神经功能的影响。方法:对长期锻炼组60例与非锻炼组60例测定时域心率变异性并进行对照分析。结果:锻炼组与对照组比较SDNN、SDANN、RMSSD、PNN50指标均有显著提高(P< 0．05)。结论:(男性)长期坚持体育锻炼能提高心率变异性。     

Effects of clonidine on heart rate variability.

We compared the effects of intravenous infusions of clonidine and placebo on heart rate variability in 10 healthy male controls. Clonidine produced a significant decrease in blood pressure and significantly decreased the heart rate variability during quiet standing.     

瑞芬太尼对中老年人心率及心率变异性的影响

目的: 观察瑞芬太尼对不同年龄组患者心率及心率变异性的影响,以及阿托品对心率的保护作用。方法: 选择行择期手术的全麻患者,先按年龄分组:中年(M,40～59岁)和老年(O,≥60岁),每一组又随机分为单纯应用瑞芬太尼(R)组和阿托品(A)预处理,共分为4个组（每组20例）:中年单纯瑞芬太尼组（RM）、老年单纯瑞芬太尼组（RO）、中年阿托品预处理组（ARM）和老年阿托品预处理组（ARO）。RM组和RO组静脉恒速泵入瑞芬太尼2 μg/kg,泵速为1 μg/(kg·min)。其余两组患者给药方式相同,只是在静脉应用瑞芬太尼之前30 min肌肉注射阿托品0.5 mg。记录用药前（T0）、用药后1 min(T1)、2 min(T2)、3 min(T3)、5 min(T5)、7 min(T7)等各时间点的心率(HR)、低高频比值(LF/HF)。结果: RM组和RO组患者的HR、LF/HF值在T1~T7各时间点,与T0相比均降低(P<0.05);而ARM组患者给药后的各时间点的HR、LF/HF值与T0相比较,未出现有统计学意义的变化;ARO组的HR和LF/HF值在给药后也出现有统计学意义的下降（P<0.05）,但与RO组相比,下降的幅度较小。结论: 静脉泵入瑞芬太尼时,中老年患者心率及心率变异性明显降低,而阿托品可以拮抗瑞芬太尼减慢心率的作用,因此瑞芬太尼应用于中老年患者时,提倡预先应用阿托品以预防心动过缓。     

美托洛尔对舒张功能不良性心衰患者心率变异性的影响

目的探讨舒张功能不良性心衰患者应用美托洛尔后心脏自主神经功能的变化。方法对照组常规抗心衰治疗,治疗组在常规抗心衰治疗的基础上加服美托洛尔,从12.5mg/d开始,缓慢增加剂量至25～50mg/d,治疗前和治疗3个月后分别进行心率变异性(HRV)分析。结果与对照组比较,治疗组治疗3个月后HRV指标SDNN、SDANN、rMSSD、PNN50均明显提高(P<0.01),且心功能改善明显优于对照组(P<0.05)。结论在常规治疗的基础上,加用美托洛尔治疗舒张功能不良性心衰,可改善心脏自主神经调节功能,可提高HRV,增强疗效。     

Effects of exercise training on the heart rate variability and QT dispersion of patients with acute myocardial infarction.

Heart rate variability (HRV) reflects the autonomic tone of the heart, and QT dispersion reflects the regional inhomogeneity of ventricular repolarization. The purpose of the present study was to determine the effects of early exercise training on HRV and QT dispersion in patients with acute myocardial infarction (AMI). Forty patients (mean age: 59 years) with AMI were randomized to training rehabilitation (group Tr, n=20) or conventional rehabilitation (group C, n=20). Two weeks after AMI, group Tr underwent 10 min of exercise using a bicycle ergometer (80% of anaerobic threshold) twice a day. At the end of the second and fourth weeks, 12-lead and 24-h Holter ECGs were recorded. QT intervals were measured and corrected using Bazett's formula (QTc), and QTc dispersion (QTcd) was defined as the difference between maximum and minimum QTc. HRV was accessed by the high-frequency component (HF: 0.15-0.40 Hz) of the HRV power spectrum (parasympathetic activity) and the ratio of low frequency (0.04-0.15 Hz) to HF (L/H ratio: sympathetic activity). In group Tr, HF increased (82.5 to 131.1 ms2), the L/H ratio decreased (3.9 to 2.6), and QTcd decreased (77.2 to 57.2 ms). In group C, none of the indices changed. It was concluded that early exercise training improves sympathovagal balance and decreases QTcd, and may reduce the arrhythmogenic substrate following AMI.     

Changes in heart rate variability in chronic uremic patients during ultrafiltration and hemodialysis

BACKGROUND: The analysis of heart rate variability (HRV) is a useful tool to evaluate cardiac autonomic modulation, which is frequently impaired in chronic uremia. AIMS: The aim of this study was to evaluate HRV in chronic uremics and to separately investigate the acute changes induced by volume depletion and solute removal during a hemodialysis session. METHODS: Fourteen uremic patients (8 males and 6 females, aged 50 +/- 15 years) on maintenance hemodialysis and 14 sex- and age-matched healthy controls were studied. Both groups underwent ambulatory electrocardiogram monitoring to evaluate the HRV time and frequency domain indices. The hemodialysis session was performed by 1 h of high-rate isolated ultrafiltration followed by 3 h of bicarbonate diffusive procedure. RESULTS: In uremic patients, the overall variability in the frequency [low-frequency power (LF): 505 +/- 473, vs. 1,446 +/- 654; high-frequency power (HF): 133 +/- 162 vs. 512 +/- 417; p < 0.001] and time domain indices (standard deviation of normal R-R intervals: 101.9 +/- 33.3 vs. 181.7 +/- 44.1 ms; p < 0.001) was markedly reduced compared to controls, whereas mean heart rate (83 +/- 12.4 vs. 60.9 +/- 8.8 bpm; p < 0.001) and LF/HF ratio (5.8 +/- 3.5 vs. 2.2 +/- 0.8; p < 0.001) were increased. Isolated ultrafiltration produced a marked further decrease in HRV indices, but the subsequent diffusive hemodialysis procedure, with a low ultrafiltration rate, made HRV increase again. CONCLUSIONS: Chronic uremics showed abnormal autonomic modulation with sympathetic-vagal imbalance. The unbalanced hypersympathetic response to body fluid depletion is related to the ultrafiltration rate. Low interdialytic weight gain and a low ultrafiltration rate, associated with adequate hemodialysis, should be the preferable strategy for uremic patients with autonomic dysfunction.     

索他洛尔(sotalol)对急性心肌梗死心率变异功率谱的影响及预后观察

２６例急性心肌梗死患者，应用索他洛尔治疗，并测定心率变异功率谱，发现用药后５天、１０天之功率谱较用药前有明显增加（Ｐ＜０．０５），与对照组相比亦有显著差异（Ｐ＜０．０５），应用索他洛尔组心肌梗死后心律失常发生率较对照组明显降低。     

维持性血液透析患者心率变异性与室性心律失常的研究进展

维持性血液透析患者心脏性猝死发生率高,而室性心律失常是其重要原因之一。研究表明：室性心律失常的发生与自主神经系统功能失衡有关,而心率变异性是公认的检测自主神经功能的无创性指标。近期研究多集中于室性心律失常,以及心率变异性在维持性血液透析过程中的变化及其影响因素,而探讨二者相关性的报道较少。因此开展这方面的研究、寻找早期预警室性心律失常发生的指标并适时调整血液透析治疗方案,对改善维持性血液透析患者的预后具有极其重要的临床意义。     

Effects of increased physical activity and mild calorie restriction on heart rate variability in obese women.

The effects of exercise and mild calorie restriction on heart rate variability (HRV) were investigated in 12 mildly obese, normotensive Japanese women aged 45.8+/-4.2 (SEM) years with a body mass index (BMI) of 27.3+/-0.4 kg/m2. The subjects participated in a 3-month program aimed at increasing physical activity and modifying eating behavior (intervention group). The control group consisted of 12 women (age 50.1+/-4.8 years, BMI 27.2+/-0.6 kg/m2) who did not attend the program. The frequency domain of HRV was calculated from 5-min Holter recordings while the subjects rested in a supine position. After 3 months, BMI decreased to 25.0+/-0.5 kg/m2 (p<0.001 vs baseline) in the intervention group, which was accompanied by decreases in body fat mass, waist circumference, serum total cholesterol and triglycerides, and improvement in insulin sensitivity. The mean and SD of the RR intervals, total power, and low and high frequency power of HRV significantly increased after the intervention, whereas no significant changes were seen for the controls. The changes in these HRV variables (calculated by subtracting the baseline values from the follow-up values) negatively correlated with the change in waist circumference, with the Pearson correlation coefficients being between -0.50 and -0.62 (p<0.05). A negative correlation was also seen between the changes in high frequency power and insulin resistance estimated by homeostasis model assessment (r=-0.49, p<0.05). The combination of exercise and mild calorie restriction led to changes in HRV indicative of an improvement in parasympathetic modulation.     

冠心病维持性血液透析患者心率减速力与心率变异性的分析

目的 测定心率减速力与心率变异性指标,分析维持性血液透析的冠心病患者自主神经功能变化.方法选择35例维持性血液透析的冠心病患者,与年龄、性别相匹配的35例肾功能正常的冠心病患者及35例心脏、肾功能正常者进行比较,采集24 h动态心电图的DC值和HRV各指标值进行统计分析.结果三组间DC值、SDNN、rMSSD和pNN50比较,差异具有统计学意义(P＜0.05);维持血液透析组与肾功能正常组 DC、SDNN、rMSSD和pNN50指标低于对照组(P＜0.05);维持血液透析组与肾功能正常组间DC值、SDNN、rMSSD和pNN50比较,差异无统计学意义(P＞0.05).结论维持血液透析的冠心病患者自主神经功能降低,但与肾功能正常的冠心病患者相比差异无统计学意义.     

糖代谢异常对高血压患者心率变异性及血压变异性的影响

目的：研究糖代谢异常对高血压患者心率变异性（heart rate variability，HRV）及血压变异性（blood pressure variability，BPV）的影响，以分析其对心血管系统植物神经功能的作用。方法：选取36例单纯高血压及33例合并2型糖尿病的高血压患者，行24h动态心电及血压监测，对两组患者的HRV及BPV进行对比分析。结果：与单纯高血压患者相比，合并糖尿病的高血压患者HRV减少（P〈0．05～〈0．01）；而BPV增大（dSBPSD、dSBPCV、24SBPSD．P〈0．05～〈0．01）。结论：糖尿病患者存在心血管系统植物神经病变，进而造成心血管的结构与功能异常，改善其心血管系统植物神经功能，可能有助于减少心血管并发症的发生。     

索他洛尔对正常人和心律失常病人心率变异性的影响

分析１０例健康志愿者和２０例室性早搏病人应用索他洛尔前后的心率变异性，旨在了解索他洛尔对ＨＲＶ的影响。结果；索他洛尔增加健康志愿者和室早病人反映迷走神经活性的ＨＲＶ时域指标，且心率变异性的改变与室早抑制无相关关系，用荭前后ＨＲＶ时域指标间相关关系无明显改变。     

Determinants of heart rate variability in heart transplanted subjects during physical exercise

Respiratory sinus arrhythmia has been described in heart transplantedsubjects. In order to investigate the mecha nisms involved inthe generation of this condition in the transplanted heart andits evolution after surgery, graded exercise was performed (0–75W in 25 W steps) on a cycle ergometer by 41 subjects (mean age44 years) who had undergone heart transplantation 28 months(range 3–60) earlier and by six age matched-control subjects.R-R interval, respiratory signal, O₂ consumption (VO₂ and CO₂production (VCO were measured. Respiratory sinus arrhythmiawas assessed by the autoregressive power spectrum of the R-Rinterval and respiration. All subjects reached the anaerobicthreshold (heart transplants: 60% at 50 W, 40% at 75W Controls:150 W). In control subjects, the respiratory sinus arrhythmiawas higher than in heart transplanted subjects (5·80± 0·30 vs 1·45 ± 0·16 lnms²) and it decreased significantly (4·66 ± 0·30In ms² P<0·05) during exercise, despite the increasein breathing rate and depth. When the group of heart transplantedsubjects was considered as a whole, respiratory sinus arrhythmiawas found to be present in all conditions. It significantlyincreased at 25 W (from 1·45 ± 0·16 to2·00 ± 0·17 In ms² P<0·01), thensignificantly fell below baseline during recovery (to 0·97± 0·23 In ms P<0·01). Multiple regressionanalysis showed that a linear combination of heart rate (inversecorrelation) and VO² (direct correlation) together with monthshaving passed since transplantation surgery, could explain theobserved changes in heart rate during exercise (multiple regression:r=0·658, P<0·0001). In five long-term transplantedsubjects, non respiratory-related low frequency (0·1Hz) waves were present on the R-R spectrum, but respiratorysinus arrhythmia is also present in the recently transplantedheart and depends on the opposing effects of ventilation andheart rate. In a few cases, sympathetic modulation (re-innervation)could not be excluded. (Eur Heart J 1996; 17: 462–471)     

慢性肾衰血液透析患者血浆儿茶酚胺水平及其心率变异性分析

目的 :观察心透患者血浆儿茶酚胺水平与心率变异性 ,并探讨两者的相关性。方法 :测定慢性肾衰血透患者血浆儿茶酚胺水平及记录 2 4h动态心电图 ,分析其心率变异性。结果 :慢性肾衰血液透析患者血浆多巴胺和去甲肾上腺素水平较对照组明显升高 （分别为 P <0 .0 1和 P≤ 0 .0 5 ） ;心率变异性时域指标 SDNN,SDANN ,SDNNindex及 r MSSD均较对照组明显降低 （P<0 .0 1） ;血浆多巴胺水平与 HRV呈明显的负相关 （SDNN:r=- 0 .45 ,P≤ 0 .0 1;SDANN:r=- 0 .43,P≤ 0 .0 1;SDNN index:r=- 0 .5 1,P<0 .0 1;r MSSD:r=- 0 .49,P<0 .0 1） ,血浆去甲肾上腺素水平亦呈类似的相关性。结论 :尿毒症心脏交感神经病变以血浆儿茶酚胺水平升高和心率变异性降低为特点 ,提示交感神经作用代偿性增强