双谱特征在基于心电图的心肌缺血检测方法中的应用

ST-T段改变是心电图检测心肌缺血的主要表现。首先,从心电信号中提取ST-T趋势信号,以便有效降低检测ST-T特征点的难度,且避免其他心电波形(如P波,QRS波)的影响;然后,对其进行双谱分析,主要的双谱特征包括双谱值、双谱权值中心(WCOB)和双谱最大幅值。实验结果表明:对心电信号进行双谱特征分析,有很好的抗噪能力;WCOB可为各心拍ST-T段的一致性分析提供一项有效的指标。经公共数据库Long-Term ST database(LTST)验证,双谱最大幅值在心肌缺血和非心肌缺血两种状态下有显著性差异,可为检测心肌缺血提供依据。     

一种基于R波和T波的心电图ST段夹逼检测方法

ST段变化是心电图(ECG)检测心肌缺血(MI)主要的临床表现,受基线漂移、体位变化、电极等因素影响,给ST段的有效检测带来困难。目前ST段常用的检测方法有:R+x和J+x,但它们受T波形态变异影响很大,且J点定位也存在一定的难度。基于上述原因,本文提出了一种方便准确的T波起点检测方法,该方法不需定位T波峰点,且受基线漂移、T波变异等的影响很小。然后联合R波峰点和T波起点提出了一种ST段夹逼检测方法,经公共数据库Long-Term ST database(LTST)验证,该方法有很好的实时性和鲁棒性,且准确率能够达到92%以上。     

基于心电图的心肌缺血非线性分析

心电图是心肌缺血检测的一种方便、经济、无创的工具,其主要的临床表现为ST-T段变化.鉴于心脏是一个混沌系统,本文从非线性角度出发,对心电图特征参数序列进行分形维数和最大Lyapunov指数分析,其中特征参数序列包括：心电图RR间期,瞬时心率HR（heart rate）,ST段的平均幅值STmean,ST段最小幅值STmin,STmean与HR的比值STr,T波峰末间期TpTe,R波峰值Ramp,T波峰值Tamp.利用公共数据库Long-term ST database（LTST）中心肌缺血和非心肌缺血心电数据,通过统计t检验分析,除最大分形维数分析中的TpTe与最大Lyapunov指数分析中的Ramp和Tamp特征参数外,其余参数均有显著性差异.基于心电图的非线性分析为心肌缺血检测与诊断提供另一重要依据.     

基于小波变换的运动心电ST段检测方法

心电图中ST段异常与心肌缺血有直接联系,在临床上是预测心肌梗死的重要指标.在静息状况下,有时心肌缺血不明显,而在运动负荷下,才能准确捕获ST段异常的现象.由于ST段信号微弱易受干扰,所以长时间运动心电检测ST段的主要障碍是基线漂移和肌电干扰.结合小波变换良好的时域定位特性和心电信号特点相结合,本文提出了QRS波群窗口滤波法.经长时间ST段数据库验证和临床实际检验,该方法具有良好的抗干扰性和准确性.     

探讨胎儿心电图ST段改变的临床价值

目的探讨胎儿心电图(FECG)ST段异常改变的临床意义.方法经腹壁间接检测孕37～42w2582例FECG-ST段异常改变进行分析.结果出现胎儿ST段异常改变者251例,占被检测总数的9.72%.其中ST段压低者135例(53.79%),ST段抬高者106例(42.23%),ST段压低和抬高同时出现者(简称混合型)10例(3.98%).其改变主要与脐带异常(63.04%)、羊水异常(25.02%)、胎盘异常(6.77%)等因素有关.胎儿宫内复苏的成功率为90.04%.结论FECF可判断宫内胎儿ST段的异常改变及其主要原因,宫内复苏对逆转胎儿ST段的异常改变具有重要的临床意义.     

动态心电图ST段分析要注意的几个问题

目前对无症状心肌缺血的诊断,判断冠心病的预后及临床疗效评价,都依赖于对动态心电图ST移位的精确定量分析进行诊断。因此在对HolteryST段分析时,对下列影响ST段记录及分析精确度的一些因素应予特别重视。一、影响ST段记录精确度的因素导联的选择三通道动态心电图记录仪CMv5导联对左室前壁引起的ST段下移较敏感,主要用于检测前壁心肌缺血;CSavf对下壁心肌缺血敏感性高,用于观察下壁心肌缺血。Holter检测对左室下壁的缺血性ST段改变敏感性较低。     

老年人ST段水平延长对冠心病的诊断价值

目的讨论老年人ST段水平延长对冠心病的诊断价值。方法回顾性分析有心绞痛病史、冠状动脉造影确诊冠心病者56例为试验组。冠状动脉造影正常者56例为对照组。比较两组患者ST段水平延长的差异,并分析其对冠心病诊断价值。结果试验组患者ST段水平延长发生率为87.5%显著高于对照组26.8%,比较具有统计学差异(P0.05);ST段水平延长诊断冠心病的敏感性为87.5%(49/56),特异性为73.2%(41/56),阳性预测值为76.6%(49/64),阴性预测值为85.4%(41/48),准确率为80.4%(90/112)。结论 ST段水平延长对冠心病诊断价值较高,具有较高的敏感性及特异性,值得临床选择。     

丹冰通颗粒对心肌缺血的保护作用

目的探讨丹冰通颗粒治疗心肌缺血的保护作用。方法采用异丙肾上腺素致大鼠心肌缺血实验模型,检测心电图ST段、心肌丙二醛(MDA)、超氧化物歧化酶(SOD)和乳酸脱氢酶(LDH)的含量;采用垂体后叶素致大鼠心肌缺血实验模型,检测对T波的影响,并检测离体大鼠心脏冠脉流量。结果丹冰通颗粒能明显抑制异丙肾上腺素所致的心肌缺血大鼠心电图ST段偏移,使血清LDH活性和MDA含量降低,SOD活性增高(P0.05)。丹冰通颗粒能明显抑制垂体后叶素所致的心肌缺血大鼠心电图T波高度的变化,可明显增加离体大鼠心脏冠脉流量。结论丹冰通颗粒对心肌缺血具有保护作用。     

动态心电图在无症状性心肌缺血患者中的诊断价值

目的:观察动态心电图在无症状性心肌缺血患者中的诊断价值。方法:收集石河子大学医学院第一附属医院2017年1月至2017年12月无症状性心肌缺血患者88例,性别不限,年龄40~82岁。根据护理人员抽签法分为动态心电图组和常规心电图组,每组44例,两组患者分别采用动态心电图和常规心电图检查,比较两组患者ST段压低幅度、心率和检出率。结果:动态心电图组患者ST段压低幅度和心率明显低于常规心电图组(P<0.05)。动态心电图组检出率为95.5%(42/44例),常规心电图组为79.5%(35/44例),差异有统计学意义(P<0.05)。结论:动态心电图在无症状性心肌缺血患者诊断中检出率高。     

冠心病Holter监测ST段缺血性改变分析

目的 了解冠心病在Holter监测中ST段缺血性改变的临床意义.方法 从192例冠心病(CAD)康复疗养病人的Holter监测结果中选出记录到心肌缺血的103例,共1066阵次ST段缺血性下移进行分组比较和统计学处理.结果 无痛性心肌缺血(SMI)67例(65%),伴典型心绞痛者11例(10.6%).心肌缺血发作的快频率依赖者66例(64%).昼夜发作规律为0-9Am发生率最高.结论 冠心痛缺血发作以无痛性缺血,快频率依赖者多见,且多发于深夜及凌晨.     

基于心电图QRS波群的心肌缺血时域分析

目的 ST-T段变化是心电图检测心肌缺血主要的临床表现,代表了心室复极的电位变化;但其特征点定位存在很大的不准确性,为了克服这一难点,本研究从心电图QRS波群出发进行心肌缺血分析.方法 从心电图QRS波群(代表了心室的除极过程)出发,综合提取QRS波群的各个时域参数,然后进行心肌缺血与非心肌缺血条件下的统计检验.结果 ...     

Automated detection of transient ST-segment episodes in 24h electrocardiograms

A novel automated system is presented for improved detection of transient ischaemic and heart rate-related ST-segment episodes in ‘real-world’ 24 h ambulatory ECG data. Using a combination of traditional time-domain and Karhunen-Loève transform-based approaches, the detector derives QRS complex and ST-segment morphology feature vectors and, by mimicking human examination of feature-vector time series and their trends, tracks the time-varying ST-segment reference level owing to clinically unimportant, non-ischaemic causes, such as slow drifts, axis shifts and conduction changes. The detector estimates the slowly varying ST-segment level trend, identifies step changes in the time series and subtracts the ST-segment reference level thus obtained from the ST-segment level to obtain the ST-segment deviation time series, which are suitable for detection of ST-segment episodes. The detector was developed using the Long-term ST database containing 24h ambulatory ECG records with human-expert annotated transient ischaemic and heart rate-related ST-segment episodes. The average ST episode detection sensitivity/positive predictivity obtained when using the annotations of the annotation protocol B of the database were 78.9%/80.7%. Evaluation of the detector using the European Society of Cardiology ST-T database as a test database showed average ST episode detection sensitivity/positive predictivity of 81.3%/89.2%, which are better performances, comparable with those of the systems being developed using the European database.     

基于心电图的心肌梗死识别分类研究

心肌梗死（MI）是一种严重的心脏病,症状前的健康检查可以发现早期的MI。心电图（ECG）是一种常用的无创健康检查诊断工具。一些使用ECG预测MI的研究存在基于私人数据集、样本量小、分析方法简单等不足。为了解决这些问题,本研究提出在英国最大的开放采集生物信息资源平台UK Biobank上进行MI的首次基准预测实验,涵盖基于临床特征的机器学习方法和基于ECG信号的深度学习方法。结果显示,基于临床特征的AUC为0.690,深度学习使用原始ECG信号的AUC为0.728,提升近4%。证明深度学习基于原始ECG信号能学习到比临床特征更多的信息。另外,对XGBoost和ResNet方法的结果进行了初步的可解释性分析,发现ST波与MI的关联更密切。     

Serum myoglobin and creatine kinase enzymes in acute myocardial infarction treated with Anistreplase.

AIMS: To compare plasma myoglobin concentration and cardiac enzyme activity with electrocardiographic (ECG) changes in two groups of patients (reperfused and non-reperfused) participating in a placebo-controlled randomised double blind trial of treatment of myocardial infarction (MI) with intravenous thrombolytic therapy (Anistreplase). METHODS: Twenty two patients with confirmed MI obeying strict inclusion and exclusion criteria were studied. Plasma myoglobin was measured by radioimmunoassay and creatine kinase enzyme (CK and CKMB) by NAC activated and NAC activated/immunoinhibition methods respectively in all patients before and at frequent intervals after injection of Anistreplase or placebo. Patients were divided into reperfused (R) and non-reperfused (NR) groups on the basis of ECG criteria. Reperfusion was diagnosed if the measured ST segment elevation fell by greater than or equal to 50% at 2 hours post dosing. RESULTS: The time to peak (TTP) myoglobin was significantly less in the R group compared with the NR group but there was considerable overlap in the range of values. The area under the enzyme time curves (AUCs) and summed ST segment epsilon ST elevations were significantly smaller in the R compared with the NR group. CONCLUSIONS: Although TTP myoglobin results were significantly lower in the R group, TTP myoglobin will probably not be useful as an non-invasive indicator of reperfusion because of the overlap in values between the two groups. The significant reduction in the AUC and epsilon ST only in the R group suggests decreased infarct size. However, in this small preliminary study reperfusion did not occur more frequently with Anistreplase than without.     

冠心病患者血清同型半胱氨酸与胱抑素C水平的相关性分析

目的 探讨冠心病患者血清同型半胱氨酸（Hcy）与胱抑素C（CysC）水平的变化及其临床意义.方法 选取218例冠心病患者与129例健康对照者,分别检测其血清Hcy与CysC水平,并进行比较与分析.结果 冠心病组的血清Hcy与CysC水平显著高于对照组（P＜0.01）,且其阳性率显著高于对照组（P＜0.01）,而联合检测的阳性率显著高于单项检测（P＜0.01）;血清Hcy与CysC对冠心病诊断有较高的特异度（分别为92.2％与97.7％）与阳性预测值（分别为89.2％与96.1％）,而灵敏度（分别为38.1％与33.9％）与阴性预测值（分别为46.9％与46.7％）不高,联合并联检测可显著提高诊断灵敏度至51.8％;血清Hcy水平与CysC水平正相关（r=0.363,P＜0.01）.结论 Hcy、CysC水平与冠心病关系密切,联合检测对于冠心病患者的诊断、治疗及预后具有重要临床意义.     

Comparison of clinical outcomes of Chinese men and women after coronary stenting for coronary artery disease：a multi-center retrospective analysis of 4,334 patients

The outcome differences between Chinese male and female patients within one-year follow-up after percutaneous coronary intervention（PCI） with stent remain unclear.The present study was aimed to compare clinical outcomes in such two populations.From May 1999 to December 2009,4,334 patients with acute myocardial infarction（MI）,unstable angina,stable angina,or silent ischemia,who underwent PCI,were registered at our centers.Among these,3,089 were men and 1,245 were women.We compared these groups with respect to the primary outcomes of MI and secondary outcomes including a composite of major adverse cardiac events（MACE） including cardiac death,MI,target lesion revascularization,target vessel revascularization（TVR）,stent thrombosis（ST）,definite ST and probable ST at one-year follow-up.Chinese male patients had a higher MACE rate（13%vs.10.7%,P =0.039）,mainly led by TVR（9.09%vs.6.98%,P=0.024） at one year,which was significantly different than female patients.Chinese male and female patients showed a significant difference on MACEs.However,there was no significant difference with respect to MI between these groups.     

p53 expression in gastrointestinal stromal tumors

The understanding of gastrointestinal stromal tumors (GIST) is complex because of their divergent differentiation and unpredictable behavior. However, our understanding is becoming clearer, despite some cases of tumors which are exceptions from the typical cases. Tumor size, mitotic rate and, to a lesser degree, location, are the most important predictive parameters for the behavior of GIST. In this study, expression of p53 protein was evaluated in 15 cases of GIST. Tumors were divided into three groups: (i) benign (mitotic index [MI] < 5/50 high-power fields [HPF] and size < 5 cm); (ii) borderline (MI < 5/50 HPF and size > or = 5 cm); and (iii) malignant (MI > or = 5/50 HPF, irrespective of size). The mean values of p53 expression in the three groups were significantly different (benign, 10.6%; borderline, 33.8%; and malignant, 71%). The conclusion of the present study is that p53 overexpression correlates well with the malignant potential of GIST.     

动态心电图ST段、QTc间期预测冠心病患者心肌缺血的价值

目的:探讨动态心电图ST段、QTc间期对冠心病(CHD)患者心肌缺血的预测价值.方法:选择高度怀疑CHD心肌缺血患者250例,完善24 h动态心电图及冠脉造影检查.分析ST段、QTc间期的诊断效能,同时绘制ROC曲线,计算曲线下面积,评估上述参数的预测价值.结果:250例患者中,冠脉造影显示182例存在心肌缺血,68例...     

Computer-assisted surveillance for detecting clonal outbreaks of nosocomial infection

Whole-house surveillance for healthcare-associated infection is no longer the recommended practice because of the large personnel time investment required. We developed a computer-based tracking system using microbiologic data as an aid in detecting potential outbreaks of healthcare-associated infections on a hospital-wide basis. Monthly total isolates of 25 clinically significant hospital pathogens were tallied from 1991 to 1998 to form a database for future comparison. Two different algorithm tools (based on increases of organism numbers over baseline) were applied to determine alert thresholds for suspected outbreaks using this information. The first algorithm (2SD) defined an alert as two standard deviations above the mean monthly number of isolates. The second (MI) defined an alert as either a 100% increase from the baseline organism number over 2 months or a >/=50% increase (compared to baseline) during a three-consecutive-month period. These two methods were compared to standard infection control professional surveillance (ICP) for the detection of clonal outbreaks over 12 months. Overall, a total of seven clonal outbreaks were detected during the 1-year study. Using standard methods, ICP investigated nine suspected outbreaks, four of which were associated with clonal microbes. The 2SD method signaled a suspected outbreak 15 times, of which three were clonal and ICP had detected one. The MI method signaled a suspected outbreak 30 times; four of these were clonal, and ICP had detected one. The sensitivity and specificity values for ICP, 2SD, and MI for detecting clonal outbreaks were 57, 43, and 57% and 17, 83, and 67%, respectively. Statistical methods applied to clinical microbiology laboratory information system data efficiently supplement infection control efforts for outbreak detection.