心率变异性检测对老年心肌梗死患者预后的临床意义

目的探讨心率变异性（ＨＲＶ）检测对老年心肌梗死（心梗）患者预后的临床意义。方法测定心梗组１０２例和健康对照组３０例的ＨＲＶ时域６项指标,并作对比分析。结果心梗患者平均Ｒ－Ｒ间期标准差的均值（ＳＤ）、ＳＤ的标准差（ＳＤＳＤ）、相邻Ｒ－Ｒ间期差值均方根的均值（ｒｍＳＡＳＤ）低于健康人,分别为（３２±１４）ｍｓ比（４３±１７）ｍｓ、（１１±７）ｍｓ比（１５±７）ｍｓ和（２０±１０）ｍｓ比（２８±１８）ｍｓ（依次为Ｐ＜０．０１、Ｐ＜０．０５、Ｐ＜０．０５）;心梗后心源性死亡者ＳＤ低于存活者〔（２５±１３）ｍｓ比（３３±１３）ｍｓ,Ｐ＜０．０５〕,其中多壁心梗死亡者ＳＤ更低于单壁死亡者〔（１６±３）ｍｓ比（２０±３）ｍｓ,Ｐ＜０．０５〕。结论心梗对ＨＲＶ有明显影响,ＨＲＶ可作为确定心梗危险分层和预测心梗预后的一个指标,定期检测ＨＲＶ对判断心梗预后有一定的临床价值。     

心率变异时域分析对糖尿病患者自主神经功能的评价

采用２４小时动态心电图对８２例糖尿病患者进行心率变异（ＨＲＶ）和心率（ＨＲ）检测。８２例分为五组：Ａ组（无血管合并症）３０例、Ｂ组（合并大血管病变）１１例、Ｃ组（合并小血管病变）１２例、Ｄ组（同时合并大、小血管病变）１９例和Ｅ组（心肾功能不全）１０例，并设正常对照组。结果：糖尿病各组ＨＲＶ显著降低，Ａ组仅２４ｈ内全部正常ＲＲ间期标准差（ＳＤＮＮ，１０４．２０±２９．１９ｍｓ）和２４ｈ内５ｍｉｎ节段平均正常ＲＲ间期的标准差（ＳＤＡＮＮｉｎｄｅｘ，９３．７３±２７．５８ｍｓ）降低（对照组分别为１２７．５２±３８．５７ｍｓ和１１６．１９±３５．７０ｍｓ），Ｐ均＜０．０１；ＨＲ异常主要表现为夜间平均ＨＲ增快，白昼平均ＨＲ仅Ｅ组（８６．７６±１１．３６ｂｐｍ）高于对照组（７６．３８±９．４０ｂｐｍ），Ｐ＜０．０１。表明糖尿病患者存在自主神经受累，白昼心率增快可能是病情严重的征兆。     

心率变异预测急性心肌梗死预后的价值

为探讨急性心肌梗死（ＡＭＩ）预后与心率变异（ＨＲＶ）的关系及ＨＲＶ与左室射血分数（ＬＶＥＦ）、心室晚电位（ＶＬＰ）联合应用对心律失常事件的预测价值，对８４例ＡＭＩ后两周的患者进行ＨＲＶ时域及频域分析和ＶＬＰ检测，并进行长期随访。平均随访１６．７５±７．７４（４～２９）个月（１２例失访）。结果表明：①发生严重心律失常事件的ＡＭＩ患者（１５例）的ＨＲＶ较无严重心律失常事件者（５７例）明显下降〔ＳＤ：３．８７９±０．３５５ｌｎ（ｍｓ）ｖｓ４．０７７±０．２８１ｌｎ（ｍｓ），Ｓｔ．Ｇｅｏｒｇｅｓ指数：３．６７７±０．５６９ｖｓ３．９２９±０．３５８，ＬＦ：４．３９９±１．１７９ｌｎ（ｍｓ２／Ｈｚ）ｖｓ５．０４１±０．９１２ｌｎ（ｍｓ２／Ｈｚ），Ｐ均＜０．０５〕。②ＨＲＶ对严重心律失常事件预测的敏感性为４６．７％，高于ＬＶＥＦ（３３．３％）及ＶＬＰ（２６．７％）；阳性预测值为３０．４％，与ＬＶＥＦ（３１．２％）及ＶＬＰ（３０．８％）相近。③ＨＲＶ分别与ＬＶＥＦ、ＶＬＰ合用，可明显提高阳性预测值（依次为６０％和５０％）。提示ＡＭＩ后心律失常事件的发生及心脏性猝死与ＨＲＶ有密切关系。     

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?     

缺血性心脏病患者心率变异性研究

应用Ｈｏｌｔｅｒ，测定４０～４９，５０～５９，６０～６９以及７０岁以上４个年龄段的缺血性心脏病患者的心率变异性（ＨＲＶ）并与相应年龄的对照组进行比较，指标为时域法的２４ｈ平均正常Ｒ－Ｒ间期标准差（ＳＤＮＮ）。结果：缺血组与对照组各年龄段比较有显著性差异，分别为：１４１．５２±２８．９２ｍｓＶＳ９３．７２±２７．５４ｍｓ；１３２．４２±２７．６３ｍｓＶＳ９３．１９±３３．１８ｍｓ；１２１．８４±２７．８７ｍｓＶＳ７４．５０±２４．０１ｍｓ；１１０．３１±２３．９６ｍｓＶＳ６３．９３±２３．７３ｍｓ，Ｐ均＜０．０１；对照组及缺血组的ＨＲＶ均随年龄增长呈下降趋势（组内比较，Ｐ均＜０．０１），呈完全负相关（ｒ（对照组）＝－０．９５，ｒ（缺血组）＝－０．９８）。随访发现缺血组中ＨＲＶ≤５０ｍｓ患者发生心源性猝死（ＳＣＤ）９例和室性心动过速１例；＞５０ｍｓ者发生ＳＣＤ２例。     

健康老年人和老年心衰,糖尿病患者心率变异性的初步分析

应用动态心电图仪，定量观察了６０例健康人（其中青年及老年人各３０例）、３０例老年心衰患者、３０例老年糖尿病患者的心率变异性。结果显示：健康老年人２４小时正常Ｒ－Ｒ间期标准差（ＳＴＳＤ）为１２３．５±１８．８ｍｓ，２４小时内连续５分钟节段正常Ｒ－Ｒ间期标准差的平均数（ＳＤ）为４５．４±１１．３ｍｓ，２４小时内连续５分钟节段平均正常Ｒ－Ｒ间期标准差（ＳＤＡＮＮ）为１１２．３±１８．３ｍｓ，２４小时内每２个相邻Ｒ－Ｒ间期大于５０ｍｓ的绝对数（ＲＲ_（５０））为５６６６．６±６２４９．２，低频频域测量（ＬＦＰＳＤ）５４４．２±２８６．４ｍｓ￣２／Ｈｚ，高频频域测量（ＨＦＰＳＤ）９０．７±１２１．２ｍｓ￣２／Ｈｚ，均明显低于青年人（Ｐ＜０．００１）。老年心衰患者的ＨＲＶ明显低于健康人，两组间的ＳＴＳＤ、ＳＤ、ＳＤＡＮＮ、ＬＦＰＳＤ比较，差异有显著性（Ｐ＜０．００１）；糖尿病患者ＳＴＳＤ、ＳＤ，ＳＤＡＮＮ，ＬＦＰＳＤ均明显低于健康人（Ｐ＜０．０１）。提示心率变异性可作为判断老年人糖尿病、心衰等预后的手段之一。     

急性心肌梗塞患者心率变异性及其临床意义

采用心率变异性（ＨＲＶ）时域指标──２４ｈ心电图中全部窦性Ｒ－Ｒ间期标准差（ＳＤＮＮ），研究急性心肌梗塞（ＡＭＩ）患者ＨＲＶ改变及其与肌酸激酶同功酶（ＣＫ－ＭＢ）、心功能和住院期间病死率的关系。结果显示：ＡＭＩ后２～３ｄ的ＳＤＮＮ（６０．５３±２０．６０ｍｓ）较正常对照组（１３０．２０±３０．４１ｍｓ）显著降低（Ｐ＜０．００１），并与ＣＫ－ＭＢ峰值呈显著负相关（ｒ＝－０．４８，Ｐ＜０．０５）；服用美多心安者的ＳＤＮＮ显著高于未服者（６１．２７±１３．４４ｍｓＶＳ４７．５３±１１．２５ｍｓ，Ｐ＜０．０５）；心功能Ⅱ～Ⅳ级者ＳＤＮＮ显著低于Ⅰ级者（４９．７１±１８．１０ｍｓＶＳ６８．５２±１８．８０ｍｓ，Ｐ＜０．０１）；住院期间死亡者ＳＤＮＮ显著低于存活者（４２．２５±６．４５ｍｓＶＳ６２．５６＋２０．６３ｍｓ，Ｐ＜０．０１）；ＳＤＮＮ＜５０ｍｓ者的住院病死率显著高于＞５０ｍｓ者（３１％ＶＳ０，Ｐ＜０．０５）。提示ＡＭＩ早期心脏交感神经活动增强而迷走神经活动受抑制，其改变的程度与心功能损害和梗塞面积相关；ＡＭＩ早期测定ＨＲＶ可获得重要临床信息和有助于对患者作早期危险性的分层。     

非持续性室性心动过速患者心率变异的研究

对非持续性室性心动过速（ＮＳＶＴ）患者进行心率变异（ＨＲＶ）分析。记录２４ｈ动态心电图分析６个ＨＲＶ时域指标，并对照分析ＮＳＶＴ发作前、后的窦性Ｒ－Ｒ间期标准差（ＳＤ）。结果：ＮＳＶＴ患者（ｎ＝３５）之ＨＲＶ时域指标中２４ｈ平均Ｒ－Ｒ间期（ＭＲＲＩ）、ＳＤ、５ｍｉｎ节段Ｒ－Ｒ间期均值的标准差（ＳＤＡ）、５ｍｉｎ节段Ｒ－Ｒ间期标准差的均值（ＭＳＤ）较正常对照组（ｎ＝１０５）明显下降（其中ＳＤ为９０．８８±３７．７７ｍｓｖｓ１４３．１８±３１．００ｍｓ，Ｐ＜０．０１），与病例对照组（ｎ＝４４）比较无显著性差异（Ｐ＞０．０５）。ＮＳＶＴ发作前、后５ｍｉｎ和１ｈ的ＳＤ（５ｍｉｎＲ－Ｒ节段）无显著性差异。结论：ＮＳＶＴ患者ＨＲＶ较正常对照组下降，但ＨＲＶ下降与ＮＳＶＴ无明显关系。     

老年高血压心肌肥厚患者的年龄与心率变异指数

目的了解老年高血压心肌肥厚患者的年龄与心率变异性指数（ＨＲＶＩ）的关系。方法１７１例老年及老年前期高血压心肌肥厚患者经超声心动图和２４小时动态心电图测定左室质量指数（ＬＶＭＩ）、左室射血分数（ＬＶＥＦ）、ＨＲＶＩ，并采用多元逐步回归法分析了年龄与ＨＲＶＩ的关系。结果ＨＲＶＩ减低的发生率和平均ＨＲＶＩ在４５～５９岁组（４５例）为５７．８％，２４．７±９．１；在６０～７４岁组（７０例），为６７．１％，２２．９±１０．３；在≥７５岁组（５６例）为７６．８％，２０．９±８．７（Ｐ＜０．０５）。多元逐步回归分析显示，ＨＲＶＩ的变化与年龄（ｒ＝－０．２７４６，Ｐ＝０．０００１２）和ＬＶＭＩ（ｒ＝－０．４０１５，Ｐ＝０．０００２１）呈负相关关系，而与ＬＶＥＦ呈正相关关系（ｒ＝０．４２８３，Ｐ＝０．００００９）。结论老年高血压左心室肥厚患者随年龄增长ＨＲＶＩ逐渐减低。     

老年人胫骨超声检测的临床意义

目的了解老年人胫骨骨强度的变化。方法用骨定量超声仪（ＱＵＳ）测量１５５例老年人和３８５例青年人胫骨超声速度（ＳＯＳ），女性同时用双能Ｘ线骨密度仪（ＤＥＸＡ）测左前臂中、远端１／３交界处骨矿密度（ＢＭＤ）。结果两组（６０～６９岁组和≥７０岁组）老年人ＳＯＳ，女性分别为３７６８±１２１和３７４８±１３２ｍｓ－１，男性分别为３９０６±１２３和３９２５±６６ｍｓ－１。老年人ＳＯＳ显著低于青年人（Ｐ＜０．００１），女性分别低５．２％±３．０％和５．７％±３．３％，男性分别低１．８％±３．１％和１．３％±１．７％，男女差异有显著性（Ｐ＜０．００１）。两组老年人骨质疏松症（ＯＰ）检出率女性分别为４６．５％和６１．１％，男性分别为１１．４％和９．１％，女性显著高于男性（Ｐ＜０．００１）。ＱＵＳ与ＤＥＸＡ的相关系数（ｒ）为０．６５７（Ｐ＜０．００１），ＯＰ检出率分别为４９．４％和５５．１％，诊断符合率为６０．０％。结论老年人胫骨ＳＯＳ明显下降，老年女性ＳＯＳ明显低于老年男性。     

Diurnal variation in cholesterol saturation of gall-bladder bile.

In order to determine whether a diurnal variation in cholesterol saturation index is present in gall-bladder bile, samples of bile were taken by nasoduodenal intubation and cholecystokinin infusion at 9 am after the conventional 12 hour fast, and also at 5 pm five hours after a meal containing no cholesterol or phospholipid. In healthy controls saturation index (mean +/- SEM) fell from 1.02 +/- 0.08 at 9 am to 0.86 +/- 0.08 at 5 pm (n = 8, p less than 0.05). In untreated cholesterol gall-stone patients saturation index fell from 1.30 +/- 0.07 to 1.04 +/- 0.07 (n = 8, p less than 0.05); on chenodeoxycholic acid 15 mg/kg/day it fell from 0.91 +/- 0.06 to 0.78 +/- 0.07 (n = 16, p less than 0.01). The degree of diurnal variation was similar in those taking chenodeoxycholic acid at bedtime and in those taking it at mealtimes. The 9 am sample was supersaturated in three non-responders (showing no evidence of gall stone dissolution on oral cholecystogram after at least six months treatment) and in four responders. The 5 pm sample was a better predictor of treatment failure, being supersaturated in all four non-responders but in only one out of the 12 responders (p less than 0.01).     

Heart rate variability as a potential diagnostic tool to predict compensatory hyperhidrosis after sympathectomy in patients with primary focal hyperhidrosis

BackgroundPrimary focal hyperhidrosis (PFH) is associated with autonomic nervous activity, and studies investigating this association in patients with PFH are very important. Heart rate variability (HRV) is a simple and noninvasive electrocardiographic test showing activity and balance in the autonomic nervous system, which consists of sympathetic and parasympathetic components. The aims of this study are to investigate associations between autonomic nervous activity and hyperhidrosis characteristics using HRV and to investigate the association between HRV findings and compensatory hyperhidrosis (CH) after sympathectomy.MethodsFrom March 2017 to March 2020, 105 subjects with PFH who underwent preoperative HRV tests and sympathectomy were analyzed. All subjects underwent bilateral thoracoscopic sympathectomy. T2 sympathectomy was conducted for craniofacial hyperhidrosis, and T3 sympathectomy was conducted for palmar hyperhidrosis. The following HRV parameters chosen to investigate the association between hyperhidrosis and autonomic nervous activity were measured by time and frequency domain spectral analysis: (I) time domain: standard deviation of normal-to-normal interval (SDNN) and square root of mean squared differences of successive normal-to-normal intervals (RMSSD), (II) frequency domain: total power (TP) of power spectral density, very low frequency (VLF), low frequency (LF), and high frequency (HF). HRV parameters were analyzed according to hyperhidrosis type (craniofacial vs. palmar type), sweat reduction, and CH after sympathectomy. In addition, the independent HRV parameters influencing CH after sympathectomy were investigated with multivariate analysis.ResultsCraniofacial hyperhidrosis was significantly more prevalent in the old age group (P<0.001). Sweat reduction after sympathectomy was significantly more prominent in palmar hyperhidrosis (P=0.037), and CH after sympathectomy was more prominent in craniofacial hyperhidrosis (P<0.001). Palmar type patients exhibited significantly larger SDNN, RMSSD, TP, LF, and HF than craniofacial type patients (all P<0.001). There were no significant differences in any HRV parameters according to sweat reduction after sympathectomy. Low-degree CH was associated with significantly larger SDNN, RMSSD, TP, LF, and HF than high-degree CH (P<0.001, P<0.001, P=0.002, P=0.001, and P<0.001, respectively). Multivariate analysis showed that HF and age group were associated with CH after sympathectomy (P=0.007 and P=0.010, respectively).ConclusionsThis study shows that HRV can provide useful insight into the pathophysiology of PFH and enhance preoperative risk stratification of CH. Large-scale, prospective studies are required to determine the predictive value of HRV in patients at risk for subsequent CH after sympathectomy.     

Host and environmental determinants of heart rate and heart rate variability in four European populations

OBJECTIVE: In a population-based sample of nuclear families recruited in the framework of the European Project on Genes in Hypertension (EPOGH), we investigated the association between heart rate (HR) and its variability (HRV), and gender, age, posture, breathing frequency, body mass index, systolic blood pressure, family history of hypertension and various lifestyle factors, such as smoking, alcohol and coffee consumption and physical activity. METHODS: RR interval and respiration were registered in the supine and standing positions (15 min each) in 1208 subjects in Bucharest (Romania, n= 267), Cracow (Poland, n= 323), Mirano (Italy, n= 323) and Novosibirsk (Russian Federation, n= 295). After exclusion of 199 participants on antihypertensive treatment and/or patients with diabetes mellitus (n= 40) or myocardial infarction (n= 4), 993 subjects were eligible for analysis. We evaluated 858 participants with high-quality recordings. Using fast Fourier transform, we decomposed HRV into low-frequency (LF: 0.04-0.15 Hz) and high-frequency (HF: 0.15-0.40 Hz) components, which were expressed in normalized units. RESULTS: Mean values were 35.3 years for age, 24.3 kg/m for body mass index (BMI) and 121.0/77.2 mmHg for blood pressure. The group included 462 (53.8%) women. Across four centres, HR and HRV were similarly and independently associated with gender, age and postural position (P <0.001). In the supine position, HR was higher in women than men (67.2 versus 63.7 bpm). Men had higher normalized LF power than women (48.8 versus 41.5), but lower HF power (40.6 versus 47.4). The normalized HF power decreased with age (r = -0.43), whereas LF power increased (r = 0.32). On standing, HR increased (83.3 versus 65.6 bpm), normalized HF power declined (19.2 versus 44.3) and LF power increased (67.4 versus 44.9). The independent effects of respiration frequency, systolic blood pressure, family history of hypertension, body mass index and lifestyle factors on HRV differed between populations, and explained no more than 8% of the total variance. CONCLUSIONS: Across four European populations, gender, age and posture were consistent and independent correlates of HR and HRV. Lifestyle seems to have small but varying influences on HR and/or HRV, probably depending on the environmental and cultural background of the population under study.     

Autonomic alterations in cocaine-exposed infants

Background Heart rate variability (HRV) reflects autonomic control of the heart. After intrauterine cocaine exposure, asymptomatic newborn infants within 72 hours of life have decreased HRV. It is unknown whether these alterations are transient (acute effect) or persist in older infants and possibly reflect a teratogenic effect of cocaine. Methods This study prospectively evaluated HRV in 2- to 6-month-old infants who were exposed to cocaine in-utero (Group 1, n = 71). Their data were compared to normal controls (Group 3, n = 77) and to newborns exposed to drugs other than cocaine (Group 2, n = 89). Based on our previous study, heavy and light cocaine exposure was also defined a priori as the amount of cocaine used during the pregnancy that was more than or less than the 70th percentile, respectively. Results At the age of 2 to 6 months, infants with in-utero cocaine exposure had higher vagal tone and higher HRV (total power) than normal controls (no exposure to drugs). Most of this increase in vagal tone occurred in the light-cocaine-exposure group. HRV and vagal tone in the heavy-cocaine-exposure group were similar to the noncocaine-exposed group. Conclusions At 2 to 6 months of age, asymptomatic infants exposed to cocaine in-utero have recovered from lower HRV seen within 72 hours of age. Infants exposed to light cocaine recovered by a rebound by increasing their vagal tone to above-normal levels. A similar response was blunted in heavily-cocaine-exposed infants. These alterations noted at follow up suggest a possible teratogenic effect of cocaine on the developing autonomic system. (Am Heart J 2002;144:1109-15.)     

Power-law behavior of heart rate variability in Chagas' disease

Beta slope is a nonlinear index derived from the power-law analysis of 24-hour heart rate variability (HRV); in healthy subjects, the beta index is typically near -1, suggesting a fractal behavior of HRV. There is scarce data on HRV in Chagas' disease. This transversal study intends to describe power-law and linear HRV patterns in different forms of Chagas' disease. Patients and healthy controls (n = 26) without other diseases were submitted to a standardized protocol, including electrocardiography, echocardiography, and 24-hour Holter monitoring. Patients with Chagas' disease were divided into groups according to their left ventricular (LV) systolic function: normal (group 1, n = 85), segmental abnormalities (group 2, n = 49), and reduced ejection fraction (group 3, n = 26). The temporal series were carefully processed to obtain the HRV indexes and beta slope. Despite the differences in the LV systolic function, the 3 groups were comparable in terms of long-term HRV index values. After adjustment for covariates, short-term HRV index values were consistently reduced in the Chagas' disease groups. The beta-index values were also diminished in Chagas' disease groups (group 1: -1.09 +/- 0.03, group 2: -1.11 +/- 0.06; group 3: -1.14 +/- 0.03; and controls: 0.95 +/- 0.03, p <0.001). This breakdown of fractal long-range correlation of RR interval dynamics, a strong predictor of mortality in other cardiomyopathies, may reflect cardiac dysautonomia that may have gone undetected in long-term time-domain analysis. This abnormality may explain the increased risk for arrhythmic sudden death found in Chagas' disease even in the absence of signs of LV dysfunction.     

Clinical and demographic determinants of heart rate variability in patients post myocardial infarction: insights from the cardiac arrhythmia suppression trial (CAST)

BACKGROUND: Clinical and demographic determinants of heart rate variability (HRV), an almost universal predictor of increased mortality, have not been systematically investigated in patients post myocardial infarction (MI). HYPOTHESIS: The study was undertaken to evaluate the relationship between pretreatment clinical and demographic variables and HRV in the Cardiac Arrhythmia Suppression Trial (CAST). METHODS: CAST patients were post MI and had > or =6 ventricular premature complexes/h on pretreatment recording. Patients in this substudy (n = 769) had usable pretreatment and suppression tapes and were successfully randomized on the first antiarrhythmic treatment. Tapes were rescanned; only time domain HRV was reported because many tapes lacked the calibrated timing signal needed for accurate frequency domain analysis. Independent predictors of HRV were determined by stepwise selection. RESULTS: Coronary artery bypass graft surgery (CABG) after the qualifying MI was the strongest determinant of HRV. The markedly decreased HRV associated with CABG was not associated with increased mortality. Ejection fraction and diabetes were also independent predictors of HRV. Other predictors for some indices of HRV included beta-blocker use, gender, time from MI to Holter, history of CABG before the qualifying MI, and systolic blood pressure. Decreased HRV did not predict mortality for the entire group. For patients without CABG or diabetes, decreased standard deviation of all NN intervals (SDANN) predicted mortality. Clinical and demographic factors accounted for 31% of the variance in the average of normal-to-normal intervals (AVGNN) and 13-26% of the variance in other HRV indices. CONCLUSIONS: Heart rate variability post MI is largely independent of clinical and demographic factors. Antecedent CABG dramatically reduces HRV. Recognition of this is necessary to prevent misclassification of risk in patients post infarct.     

睡眠呼吸暂停综合征对高血压病患者血压昼夜节律及心率变异性的影响

目的探讨阻塞性睡眠呼吸暂停（OSAS）对高血压病患者血压昼夜节律及心率变异性（HRV）的影响。方法入选62例高血压病患者,根据是否合并OSAS分为：单纯组（无合并OSAS）及合并组（合并OS-AS）,另选择同期30名健康人群作为对照组。比较三组患者呼吸紊乱指数（AHI）、夜间平均血氧水平、昼间及夜间血压水平、非杓型血压的比例、HRV频域指标（SDNN、PNN50）与时域指标（低频谱、高频谱）的差异。结果合并组与单纯组、对照患者比较夜间平均血氧水平、AHI、HRV频域指标（SDNN、PNN50）与时域指标（低频谱、高频谱）差异均有显著统计学意义（P均〈0.01）;合并组非杓型血压的比例显著高于其他两组,差异有显著统计学意义（P〈0.01）。结论 OSAS增加高血压病患者血压昼夜节律异常及心率变异性。     

The normal hourly variation of blood pressure in women: average patterns and the effect of work stress.

The purpose of this study was to examine the pattern of diurnal variation of blood pressure in normotensive working women, and to assess the effect of work stress on this pattern. The subjects were 121 normotensive (based on clinic readings less than 140/90 mmHg) young women (age = 30.2 +/- 7.3 years; range 20-50) who wore an ambulatory blood pressure monitor on a workday from 9 am to 6 am the next day. The effect of work stress on the pattern of variation was assessed by comparing the hourly averages among women who perceived greater stress at work on the day of study ('work stressed') (n = 67) with those of women who perceived greater or equal stress at home on the day of study ('home stressed') (n = 54). The results showed that the systolic pressure of 'work stressed' women was 5-8 mmHg higher (P less than 0.05) and diastolic 3-4 mmHg higher (P less than 0.05) than 'home stressed' women for nearly every hour from 9 am to 6 pm. From 7 pm to 6 am, both groups were similar hour by hour. These data suggest that there is no intrinsic pattern of diurnal blood pressure variation (other than an awake-sleep cycle) in working women. The data also provide a reference standard for comparison with hypertensive women.     

A three-day course of intravenous omeprazole plus antibiotics for H. pylori-positive bleeding duodenal ulcer.

BACKGROUND/AIMS: This prospective trial aimed to test the efficacy of 3-day intravenous omeprazole plus antibiotics for Helicobacter pylori (H. pylori) eradication rate, and to see whether individualized response to omeprazole in intragastric pH elevation will alter the success of eradication. METHODOLOGY: One hundred and thirty-eight cases with H. pylori-positive duodenal ulcer bleeding were randomized into four therapy groups: Group 1 (n = 32) received a 3-day course of intravenous omeprazole (80 mg loading then 40 mg q 9 am & 9 pm) plus ampicillin/salbactum (1.5 gm i.v. loading then 750 mg q 9 am, 3 pm, & 9 pm); Group 2 (n = 35) followed protocol as for Group 1 except the antibiotics were metronidazole and erythromycin (both 500 mg i.v. q 9 am, 3 pm, & 9 pm). Group 3 (n = 31) followed protocol as for Group 1 and further added with erythromycin (both 500 mg i.v. q 9 am, 3 pm, & 9 pm). Group 4 served as a control group (n = 40) receiving oral dual therapy after leaving the emergency room (omeprazole 20 mg and amoxycillin 1 g bid x 2 weeks). In each case, three gastric biopsies were done for total histologic density of H. pylori (THPD) (range: 0-15) before, 1 day and 6 weeks after completion of therapy. Except for the control group, the 24-hour ambulatory intragastric pH meter (MIC Inc, Gastrograph Spark III, Swiss) was inserted as possible on the 2nd day of therapy. RESULTS: The 3-day intravenous regimens achieved high clearance rates of H. pylori (Group 1: 93.8%; Group 2: 93.9%; Group 3: 100%). The eradication rates of H. pylori in Groups 1-4 were 43.8%, 57.1%, 58.1%, and 72.8%, respectively. In Groups 1-3, the H. pylori-eradicated cases had lower pre-treatment THPD than non-eradicated cases (6.01 vs. 9.24, p < 0.001). Among 72 cases with pH meter insertion, the percentage of intragastric pH > 5.3 during 24-hour was not different among 35 H. pylori non-eradicated and 37 eradicated cases (78.7 vs. 76.7%, p > 0.05). CONCLUSIONS: The 3-day intravenous regimens may achieve clearance of H. pylori quickly. However, they were not so effective for eradication, especially in cases with higher bacterial loads. The interindividual response to omeprazole in intragastric pH elevation under the study dosage had insignificant variations to alter the success of eradication.     

Effects of physical training on heart rate variability in patients on hemodialysis.

Dysfunction of the cardiac autonomic nervous system is a known complication of end-stage renal disease. The objective of the study was to mainly investigate the effects of physical training on 24-hour vagal cardiac activity in dialysis patients. Sixty chronic uremic patients (mean age 48 +/- 12 years) on maintenance hemodialysis were studied. After initial evaluation, 30 patients (group A) were randomly assigned to a 6-month exercise training program (3/week). The other 30 patients (group B) and 30 nonuremic sedentary persons (group C) remained untrained and were used as controls. Parasympathetic activity was assessed at the beginning and the end of the study noninvasively from 24-hour electrocardiographic ambulatory monitoring by calculating heart rate variability (HRV). HRV index, mean NN interval, and standard deviation NN (SDNN) were measured according to the "triangular method." At baseline HRV index, mean RR, SDNN, and aerobic capacity were significantly reduced in both hemodialysis groups compared with values in group C. Also, 40% of all patients on hemodialysis and 16% of group C had arrhythmias (Lown class >II). Moreover, hemodialysis patients with a more depressed HRV index (<25, n = 37) had a higher incidence of arrhythmias (60%) compared to those with HRV index >25 (p <0.05). Exercise training in group A significantly increased HRV index from 22 +/- 7 to 28 +/- 9 (p <0.05) and SDNN from 0.11 +/- 0.03 to 0.13 +/- 0.04 (p <0.05). Furthermore, fewer patients continued to have an HRV index <25 (by 40%) and arrhythmias (by 33%) compared with baseline data. Training was also associated with a significant improvement in fitness level, as assessed by maximal oxygen consumption (by 41%; p <0.05) and exercise testing duration (by 33%; p <0.05). There was a significant correlation in HRV index and maximal oxygen consumption. No changes were observed in the control groups between baseline and follow-up data. Results demonstrate that physical training in hemodialysis patients augments cardiac vagal activity and decreases vulnerability to arrhythmias.