Reliability of Ultra‐Short ECG Indices for Heart Rate Variability

Background: Heart rate variability (HRV) is an accepted and reliable means for assessing autonomic nervous system dysfunction. A 5‐minute measurement of HRV is considered methodologically adequate. Several studies have attempted to use shorter recordings of 1–2 minutes or 10 seconds. The aim of this study was to determine the reliability of HRV parameters calculated from ultra‐short electrocardiogram recordings. Methods: Seventy healthy volunteers were recruited for the study. HRV was evaluated for 5 minutes according to accepted procedures. Thereafter, HRV parameters were recalculated from randomly selected 1‐minute and 10‐second intervals. The standard and ultra‐short measurements were correlated using intraclass correlation coefficients. Results: Good correlations between the 5‐minute electrocardiograms (ECGs) and both the 1‐minute and 10‐second ECGs were noted for average RR interval, and root mean square of successive differences in RR intervals (RMSSD). No correlation was noted for standard deviation of the RR interval (SDNN) and several other HRV parameters. Conclusions: RMSSD, but not SDNN, seem a reliable parameter for assessing HRV from ultra‐short (1 minute or 10 seconds) resting electrocardiographic recordings. Power spectral analysis and evaluation of other HRV parameters require longer recording periods. Further research is required to evaluate the importance of ultra‐short RMSSD for cardiovascular risk stratification. Ann Noninvasive Electrocardiol 2011;16(2):117–122     

老年高血压合并糖尿病患者心率变异性及其昼夜变化临床分析

目的研究老年高血压合并糖尿病患者的心率变异性(HRV)及其昼夜变化规律,探讨老年糖尿病患者心脏自主神经变化的临床意义。方法选择87例原发性高血压患者(EH组)及68例高血压合并糖尿病患者(EH+DM组),监测24 h动态心电图,进行HRV时域指标SDNN、SDANN、SDNN Index、RMSSD、PNN50的分析。比较2组间HRV指标的差异以及HRV昼夜指标差异。结果 EH+DM组较EH组24 h、日间、夜间HRV各项指标均明显降低,且有统计学差异;EH组SDNN以及RMSSD呈昼低夜高,但无明显统计学差异,SDNN Index和PNN50仍呈昼低夜高现象(P0.01);EH+DM组SDNN以及RMSSD呈昼高夜低现象(P0.05),SDNN Index和PNN50昼夜间无统计学差异。结论老年高血压合并糖尿病患者HRV显著降低,高血压患者昼夜节律已有明显受损,高血压合并糖尿病患者昼夜节律进一步受损,心脏自主神经功能失调。     

糖尿病与冠心病患者心率变异性分析

目的 探讨糖尿病与冠心病患者心率变异（ＨＲＶ）改变及其异同,并观测疾病状态下ＨＲＶ改变的昼夜节律性。方法 观察２５例糖尿病患者、２例冠心病患者及４８名健康人２４ｈ、白天段及夜间段心率变异长程时域。结果 糖尿病组与冠心病组ＨＲＶ各指标ＳＤＮＮ、ＲＭＳＳＤ、ＰＮＮ５０、ＳＤＡＮＮ均显著低于健康对照组（Ｐ〈０．０１）。糖尿病组与冠心病组及２组内白天与夜间ＨＲＶ各指标比较均无显著性差异。结论 糖尿病、冠心     

慢性肾功能不全患者的心率变异性分析

目的 引入心率变异性（HRV）分析的方法，评价慢性肾功能不全（CRI）患者的自主神经功能受损状况，并了解HRV变化与肾功能水平之间的关系。方法 CRI患者30例，正常人30名，采用olter-Star系统进行24h长程心电图监测和HRV分析，比较两组间HRV指标的总体差异及昼夜节律性，并将CRI患者按肾功能受损严重程度分为三个亚组，观察HRV指标与肾功能指标间的关系及三个亚组间的HRV差异性。结果 与正常人相比，CRI患者的所有14项HRV指标均极显著降低，且无昼夜节律变化，仅有部分HRV指标（SDNN、SDANN、RMSSD、TINN及Triangular Index等）与肾功能指标（BUN、Scr、Ccr）之间存在一定的相关性，而且其变化与肾功能的恶化相平行。结论 CRI患者有严重的自主神经功能受损，主要表现为迷走神经张力减退，HRV分析可作为有效的评价方法。     

Comparison of heart rate variability and treadmill exercise score in patients with stable coronary artery disease

Depressed heart rate variability (HRV) is associated with increased mortality and morbidity with various forms of heart disease, and the Duke treadmill score (DTS) provides diagnostic and prognostic information for the evaluation of patients with coronary artery disease (CAD). Our study was aimed at assessing any possible correlation between HRV and DTS in stable CAD. We evaluated the correlation between the HRV assessed by using 24 hour ambulatory ECG monitoring, and treadmill exercise score in 37 patients with angiographically proven and clinically stable CAD. In univariate analysis, DTS showed a significant negative correlation with age (r=–0.89, p<0.01) and a significant positive correlation with the square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD) (r=0.67, P<0.05), percent difference between adjacent normal R-R intervals >50 ms (PNN50) (r=0.69, P<0.05), and mean of the standard deviation of all R-R intervals in all the 5-minute intervals (HRVM) (r=0.63, P<0.05). There is no significant correlation between DTS and standard deviation of all R-R intervals (SDNN), standard deviation of the averages of R-R intervals in all 5-minute segments of the entire recordings (SDANN) and standard deviation of the SDNN in all the 5-minute intervals (HRVSD). In multiple regression analysis, age was the only independent significant predictor of DTS (p<0.01). DTS decreased with advancing age. SDNN, SDANN, RMSSD, HRVM and HRVSD were not apparent predictors for detecting of DTS. Age was an independent predictor of DTS. Although DTS was correlated with RMSSD, PNN50 and HRVM in patients with stable CAD, time domain parameters of HRV were not appearent predictor for DTS.     

老年急性心肌梗塞心率变异时域分析

目的分析急性心肌梗塞（ＡＭＩ）后老年患者心率变异（ＨＲＶ）时域指标，了解ＡＭＩ后ＨＲＶ变化。方法以多单位协作方式对１５７例ＡＭＩ后２周的老年患者行动态心电图检测ＨＲＶ时域法５项指标，并与健康老年组对比分析。数据经ＥｐｉＩｎｆｏ（６．０）统计软件处理。结果①ＡＭＩ患者的正常Ｒ－Ｒ间期标准差（ＳＤＮＮ）、平均值的标准差（ＳＤＡＮＮ）和标准差的平均值（ＳＤＮＮＩｎｄｅｘ）低于对照组（Ｐ＜０．０１），而相邻正常Ｒ－Ｒ间期差值的均方根（ＲＭＳＳＤ）和相邻正常Ｒ－Ｒ差值大于５０ｍｓ记数占总Ｒ－Ｒ间期数的百分比（ＰＮＮ５０）虽低于对照组，但无显著差异（Ｐ＞０．０５）。②ＡＭＩ后ＨＲＶ时域５项指标男、女性别间无显著性差异（Ｐ＞０．０５）。③ＳＤＮＮ、ＳＤＡＮＮ和ＳＤＮＮＩｎ－ｄｅｘ在心肌梗塞各部位间无显著差异（Ｐ＞０．０５），ＲＭＳＳＤ和ＰＮＮ５０前间壁低于下壁心肌梗塞（Ｐ＜０．０５）。结论老年人ＡＭＩ后ＨＲＶ降低。反映交感神经活性的ＳＤＮＮ、ＳＤＡＮＮ和ＳＤＮＮＩｎｄｅｘ和反映迷走神经活性的ＲＭＳＳＤ和ＰＮＮ５０２组指标变化不相同。     

2型糖尿病患者无症状心肌缺血心率变异性的研究

目的冠心病是2型糖尿病主要心血管并发症,且经常表现为无症状心肌缺血（SMI）,本研究观察2型糖尿病患者SMI发作与心率变异性的相关性。方法在我院行运动负荷心肌灌注显像检查的患者中,选取1个月内做过动态心电图监测的157名无冠心病临床症状的2型糖尿病患者,其中34例为SMI患者;123例为无心肌缺血发作患者,并在其中随机选37例为对照组。结果SMI的发生率为21．6％;SMI组除24小时平均心率高于无心肌缺血组外。心率变异性各参数中：总体标准差、均值标准差、标准差均值、差值的均方根和差值〉50ms的百分比与无心肌缺血组相比较均明显下降。结论心率变异性减低与2型糖尿病合并SMI明显相关,而心率变异性减低作为评价心脏神经自主病变的早期信号,说明2型糖尿病合并SMI的发病与心脏自主神经病变密切相关,心率变异性或可作为无症状的2型糖尿病患者SMI筛查的指标之一。     

替米沙坦对2型糖尿病患者心率变异性的影响

目的 研究替米沙坦对2型糖尿病患者心率变异性的影响.方法 2型糖尿病40例及2型糖尿病并高血压40例,服用替米沙坦,分别在治疗前与治疗14周后进行动态心电图及心率变异性(heart rate variability,HRV)检查,并与对照组40例进行比较.结果 替米沙坦治疗后正常R-R间期标准差(standard deviation of normal number of intervals,SDNN),正常相邻R-R均方差(root mean square values of the standard deviation between adjacent normal number of intervals,RMSSD),相邻R-R间期大于50 ms百分数(percentage of differences exceeding 50 ms between adjacent normal number of intervals,PNN50)、高频功率(high frequency,HF)值均上升;低频功率(low frequency,LF),与高频功率比值(LF/HF)降低,差异有统计学意义(P＜0.05).结论 2型糖尿病患者存在HRV时域指标下降而频域指标升高,并高血压患者改变更明显,而替米沙坦可改善HRV,有可能改善预后.     

Heart rate variability measures during sinus rhythm predict cycle length entropy during atrial fibrillation

Introduction: Several noninvasive measures of cardiac risk such as heart rate variability (HRV) cannot be used in patients with atrial fibrillation (AF). One promising exception is the measure of ventricular cycle length entropy (VCLE) where initial data suggest that a reduction in VCLE portends an increased risk of cardiac death in patients with chronic AF. In this study, we hypothesized that measures of short‐term HRV during sinus rhythm would correlate with measures of cycle length entropy during paroxysms of AF. Methods: We tested 25 Holter recordings of paroxysmal AF from the Physionet AF Prediction Database. We calculated HRV parameters including standard deviation of all NN intervals (SDNN), the root mean square root of the differences between adjacent NN intervals (RMSSD), standard deviation of 5‐minute averages of NN intervals (SDANN), percentage of adjacent NN interval differences >50 ms (pNN50), and interbeat correlation coefficient (ICC) from 30 minutes of normal sinus rhythm, and entropy measures (the Shannon Informational Entropy [ShEn] and Average of Approximate Entropy [ApEn]) from 5 minutes of AF that occurred during the same 24‐hour monitor. Pairwise correlations were used to assess associations, as regression residuals were normally distributed. Results: The mean entropy measures during AF were: ShEn: 4.78 ± 0.82, ApEn: 0.198 ± 0.21. When assessed during the 30 minutes immediately preceding AF onset, ICC showed a significant negative correlation with both ShEn (r =–0.65, P < 0.001) and ApEn (r =–0.60, P < 0.01). RMSSD also correlated with both ShEn (r = 0.41, P = 0.04) and ApEn (r = 0.39, P = 0.05), but other HRV measures showed no correlation with VCLE during AF. Conclusion: Reductions in RMSSD or increases in ICC, two short‐term HRV measures that are known to reflect parasympathetic function in sinus rhythm, are correlated with reductions in the entropy of ventricular response intervals during AF. Our findings suggest that entropy during AF may be modulated, in part, by vagal innervation.     

40岁以上正常人的心率变异分析

报道５０例正常人的心率变异分析。按参数间密切相关将６项频域、１０项时域参数分成三组：总频成分（ＴＯＴ）、超低频成分（ＵＬＦ）极低频成分（ＶＬＦ）、连续５ｍｉｎ正常Ｒ－Ｒ间期标准差均值（ＡＳＤ）；高频成分（ＨＦ）、相邻正常Ｒ－Ｒ间期差值均方根（ＲＭＳＳＤ）、相邻正常Ｒ－Ｒ间期超过５０ｍｓ的百分比（ＰＮＮ５０）、ＲＭＳＳＤ心率校正值（ＲＭＳＤＣ）及正常Ｒ－Ｒ间期标准差（ＳＤ）、ＳＤ心率校正值（ＳＤＣ）、连续５ｍｉｎ正常Ｒ－Ｒ间期均值的标准差（ＳＤＡ）、ＳＤＡ的心率校正值（ＳＤＡＣ）。健康男性ＳＤ显著高于女性，女性ＲＭＳＤＣ显著高于男性。各参数随年龄增长而变小，年龄与低频成分（ＬＦ）和ＡＳＤＣ（ＡＳＤ的心率校正值）相关最密切（ｒ分别为－０．６５和－０．６１），其次与ＲＭＳＤＣ、ＰＮＮ５０、ＨＦ、ＶＬＦ、ＲＭＳＳＤ、ＴＯＴ、ＡＳＤ、ＳＤＣ、ＳＤ等呈显著负相关（Ｐ＜０．０５）。心率与ＴＯＴ、ＵＬＦ、ＶＬＦ、ＳＤ、ＡＳＤ、ＲＭＳＳＤ等呈负相关（Ｐ＜０．０５）。多项参数有明显昼夜规律。     

2型糖尿病患者心率变异与下肢动脉病变关系的研究

目的　探讨 2型糖尿病患者心率变异 (HRV)各指标的变化 ,了解HRV与 2型糖尿病患者下肢动脉病变的关系及其临床意义。方法　将 2 0 0 1- 0 2～ 2 0 0 3- 11浙江大学医学院附属第一医院住院的 135例 2型糖尿病患者 (其中 6 7例无下肢动脉病变、6 8例合并下肢动脉病变 )及 2 0例正常对照者作为研究对象 ,所有研究对象测定了心率变异中总体标准差 (SDNN)、均值标准差 (SDANN)、标准差平均值 (SDNN指数 )、差值均方的平方根 (RMSSD)、爱丁堡指数 (PNN5 0 )、低频与高频比 (LF/HF)各指标。结果　 (1) 2型糖尿病有或无下肢动脉病变组各HRV指标除LF/HF外均较正常对照组低 ,差异有显著性。 (2 ) 2型糖尿病合并下肢动脉病变患者心率变异指数较无下肢动脉病变患者有进一步的下降 ,而且心率变异指数与下肢动脉病变程度呈负相关。结论　心率变异是 2型糖尿病下肢动脉病变的独立相关因素。     

Cigarette Smoking and Heart Rate Variability: Dynamic Influence of Parasympathetic and Sympathetic Maneuvers

Background: Cigarette smoking has been associated with increased activity of the sympathetic nervous system. In this study, we investigated cardiac autonomic function in heavy smokers and nonsmoker controls by analysis of heart rate variability (HRV). Method: Twenty‐four long‐term heavy smokers (men) and twenty‐two nonsmoker subjects (hospital staff) were included to study. Time domain [mean R‐R interval (RR), the standard deviation of R‐R interval index (SDNN), and the root mean square of successive R‐R interval differences (RMSSD)] and frequency domain [high frequency (HF) low frequency (LF), and LF/HF ratio] parameters of HRV were obtained from all participants after 15 minutes resting period in supine position (S), during controlled respiration (CR), and handgrip exercise (HGE) over 5‐minute periods. Results: Baseline SDNN and RMSSD values were found to be lower in smokers than in nonsmokers. (64 ± 10 vs 78 ± 22, P < 0.05 and 35 ± 12 vs 54 ± 30 ms, P < 0.05). Baseline LF/HF ratio was also found to be higher in smokers than in nonsmokers (1.3 ± 0.6 vs 0.9 ± 0.5 ms, P < 0.05). The other HRV parameters including R‐R interval, LF, and HF were not significantly different. During CR, expected increase in RR, SDNN, and RMSSD did not occur in smokers, while it did occur in nonsmokers. Most HRV indices were significantly affected by HGE in both groups. In addition, the duration of smoking was found to be inversely correlated with RMSSD and HF and positively correlated with LF/HF ratio. Conclusion: Vagal modulation of the heart is blunted in heavy smokers, particularly during a parasympathetic maneuver. Blunted autonomic control of the heart may partly be associated with adverse event attributed to cigarette smoking.     

原发性高血压合并2型糖尿病患者心率变异性与心脏变时功能不全的特点及相关性

目的 探讨原发性高血压合并2型糖尿病患者的心率变异性和心脏变时功能不全特点. 方法 原发性高血压合并2型糖尿病患者与健康人各40例,行24 h动态心电图检查,计算心脏变异性指标SDNN、SDANN、RMSSD、PNN50;行平板运动试验检查,计算运动中最大心率、心脏变时指数、心率储备率,分析心脏变时指数和心率储备率与SDNN、SDANN、RMSSD、PNN50的相关性. 结果 原发性高血压合并2型糖尿病患者SDNN、SDANN 、RMSSD、PNN50均较健康者降低（P〈0.01）.最大心率、心脏变时指数、心率储备率明显低于健康者（P〈0.01）;SDNN、SDANN、RMSSD及PNN50与心脏变时指数（r=0.522、0.472、0.337、0.321）和心率储备率（r=0.541、0.480、0.351、0.285）均存在明显正相关. 结论 原发性高血压合并2型糖尿病患者心脏自主神经受损明显,表现为迷走神经功能减退和交感神经兴奋性增高.     

急性心梗患者心率减速力与心率变异性

目的:探讨急性心肌梗死(AMI)患者心率减速力(DC)与心率变异(HRV)、心率震荡(HRT)的相关性.方法62例窦性心律的AMI患者和51例非AMI对照组进行24h动态心电图检查,离线计算DC、HRV时域指标、HRT的两个参数震荡初始(TO)和震荡斜率(TS).结果:AMI患者的DC值、HRV降低;HRT减弱;且DC...     

Paper electrocardiograph strips may contain overlooked clinical information in screen-detected type 2 diabetes patients

Background

A large number of nondigitized electrocardiograph (ECG) strips are routinely collected in larger cohort studies such as the ADDITION study (Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen-Detected Diabetes in Primary Care). These ECG strips are routinely read manually but may contain overlooked information revealing cardiac autonomic dysfunction. The aim of this study was to investigate whether clinical information may be lost using manual R wave to R wave (RR) interval measurements in the calculation of heart rate variability (HRV) in patients with type 2 diabetes mellitus (T2DM).

Method

From the Danish part of the ADDITION study, we randomly selected 120 T2DM patients at baseline of the ADDITION study. Analysis of the ECG strips was performed using two different methods: (1) by experienced technicians using rulers and (2) by experienced technicians using a high-resolution computer-assisted method. Calculation of heart rate and time domain HRV [standard deviation of normal-to-normal RR intervals (SDNN) and root mean square of successive differences (RMSSD)] were performed with the same software.

Results

When comparing results from the two methods, the following values of Pearson''s r are obtained: 0.98 for heart rate, 0.76 for SDNN, and 0.68 for RMSSD. These results indicate that heart rate and HRV measurements by the computer-assisted and manually based methods correlate. However, Bland-Altman plots and Pitman''s test of difference in variance revealed poor agreements (p < .01) for both HRV measurements (SDNN and RMSSD); only heart rate showed substantiated agreement (p = .54) between the two methods. Low HRV was statistically significantly associated to high heart rate, systolic blood pressure, and diastolic blood pressure in these screen-detected T2DM patients.

Conclusions

Paper ECG strips may contain overlooked clinical information on the status of autonomic function in patients with T2DM. In our study, manual measurements of RR intervals were inferior to the computer-assisted method. Based on this study, we recommend cautiousness in the clinical use and interpretation of HRV based on manual or low resolution measurements of RR intervals from ECG strips. High resolution measurements of RR intervals reveal significant associations between low HRV and high heart rate, systolic blood pressure, and diastolic blood pressure among patients with screen-detected T2DM. It is feasible to use a computer-assisted method to determine RR intervals in patients with T2DM.     

扩张型心肌病患者心率减速力的临床研究

目的:研究心率减速力(DC)在扩张型心肌病(DCM)患者中的变化以及与左室射血分数(LVEF)、心率变异性(HRV)之间的关系。方法:32例DCM患者和34例正常人接受24h动态心电图检查和超声心动图检查,计算机分别测定2组患者的DC、LVEF及HRV时域指标(SDNN,RMSSD)与标化的频域指标(LFn、HFn);比较2组患者的DC、LVEF、SDNN,RMSSD、LFn及HFn,并研究DCM患者的DC与LVEF及HRV各指标之间的关系。结果:DCM患者的DC值明显小于正常对照组(3.3±2.3msvs6.9±1.4ms,P<0.01),其异常DC的发生率高达89.7%,明显高于正常对照组(P<0.01);DCM组患者的DC与LVEF、SDNN、RMSSD、LFn及HFn之间呈明显的正相关关系。结论:DCM患者的DC值明显降低,DC是一项可用以定量评估DCM患者自主神经张力并筛选高危患者的新的可靠指标。     

抑郁症患者心率减速力与心率变异性的相关陛

目的探讨抑郁症患者心率减速力（Dc）与心率变异性（tmv）的相关性。方法选择80例抑郁症患者和80例正常对照组，进行24h动态心电图监测，离线计算DC、HRV时域指标。结果抑郁症患者的DC值、HRV降低，且Dc与时域指标SDNN、RMSSD、PNN50呈显著正相关（p〈0．01）。结论抑郁症患者的Dc值明显降低，且Dc指标和HRV指标有较好的相关性，DC是一项评估自主神经功能状态的新的可靠指标。     

Effects of cigarette smoking on the circadian rhythm of heart rate variability

BACKGROUND: The effects of cigarette smoking on the circadian rhythm of heart rate variability (HRV) are not known. METHODS: We studied the effects of cigarette smoking on the circadian rhythm of HRV in 24 smoking and 21 non-smoking healthy subjects. Twenty-four hour ambulatory electrocardiograms were recorded and time domain parameters of HRV (SDNN [standard deviation of all R-R intervals], SDANN [standard deviation of the averages of R-R intervals in all 5-minute segments of the entire recording], RMSSD [the square root of the mean of the sum of the squares of differences between adjacent R-R intervals]) were determined for the entire 24-hour period and for each 3-hour period. RESULTS: In total, SDNN and SDANN were significantly lower in smokers than non-smokers (116 +/- 26 vs 136 +/- 27, p < 0.05 for SDNN, 109 +/- 25 vs 121 +/- 24, p < 0.05 for SDANN). However, there were no statistical differences between smokers and non-smokers in heart rate (81 +/- 9 vs 76 +/- 10, p > 0.05) and RMSSD (32 +/- 12 vs 37 +/- 18, p > 0.05). These HRV parameters showed a circadian variation: they increased at night and decreased during the day in both groups. The parameters were lower in smokers than non-smokers during daytime (especially, between 8-14 hours). However, no differences were detected during night-time. CONCLUSIONS: Time domain parameters of HRV (SDNN, SDANN and RMSSD) in both smoking and non-smoking healthy subjects have a circadian rhythm. SDNN and SDANN were lower in smokers than non-smokers during daytime.     

Dynamics of parameters of heart rate variability after radiofrequency ablation in patients with paroxysmal supraventricular tachycardia: holter ECG monitoring data

Changes of parameters of heart rate variability (HRV) in patients with supraventricular tachycardia (SVT) immediately after radiofrequency ablation (RFA) have been demonstrated earlier. However dynamics of HRV parameters after RFA has not been sufficiently studied. For elucidation of dynamics of HRV parameters in patients with SVT after RFA we conducted analysis of HRV basing on data of 24 hour Holter ECG monitoring before RFA, on day 2, in 1 week and 1 month after intervention in 27 patients with paroxysmal SVT. Statistically significant lowering of temporal (SDNNi, RMSSD, NN50, pNN50) and spectral (VLF, LF, HF) HRV parameters were found on day 2 and in 1 week after RFA compared with data obtained before intervention. In 1 month after RFA the studied parameters of HRV did not differ from baseline values. Reversible changes of HRV parameters evidencing for transitory autonomic dysfunction are observed after RFA.     

严重充血性心力衰竭患者自主神经功能与心率变异的关系及地高辛的影响

对２５例重度充血性心力衰竭（ＣＨＦ）患者在地高辛治疗前后测定血浆去甲肾上腺素（ＮＥ）及心率变异（ＨＲＶ）。结果显示：ＮＥ基础值与ＨＲＶ时域指标基础水平均呈负相关（Ｐ＜０．０５或＜０．０１）。地高辛治疗前后的ＮＥ相比（２９１±８０ｐｇ／ｍｌｖｓ２１３±８２ｐｇ／ｍｌ），Ｐ＜０．００１。２４小时平均ＲＲ间期及２４小时正常ＲＲ间期标准差由治疗前的７２７±１２３ｍｓ及６７．７±２１．８ｍｓ分别增加至７７７±１２２ｍｓ及８７．２±２９．２ｍｓ（Ｐ均＜０．０５）；２４小时相邻ＲＲ间期差值的均方根（ＲＭＳＳＤ）、２４小时正常相邻ＲＲ间期之差大于５０ｍｓ的心搏数所占百分比（ＰＮＮ５０）及高频（ＨＦ）由治疗前的３６．３±３０．６ｍｓ、５．３±５．５％及３７．１±２１．２ｍｓ２分别增加至５６．１±４３．７ｍｓ、１０．８±１０．６％及７９．９±５８．２ｍｓ２（Ｐ值＜０．０５至＜０．０１）；低频（ＬＦ）由治疗前的１１８．９±１３３．２ｍｓ２增加至１７１．２±１７２．８ｍｓ２（Ｐ＜０．００５）；ＮＥ下降幅度与时域指标增加幅度均呈正相关。ＨＲＶ多数时域指标增加幅度及其绝对值与血清地高辛浓度呈正相关，以ＲＭＳＳＤ和ＰＮＮ５０尤为显著（Ｐ?