一种室性QRS波检出技术

本文提出了一种ＡＥＣＧ分析中宇上检出的新方法，包括噪声检出、ＱＲＳ检出、特征提取和ＱＲＳ波形分类。     

A new approach of QRS complex detection based on matched filtering and triangle character analysis

QRS complex detection usually provides the fundamentals to automated electrocardiogram (ECG) analysis. In this paper, a new approach of QRS complex detection without the stage of noise suppression was developed and evaluated, which was based on the combination of two techniques: matched filtering and triangle character analysis. Firstly, a template of QRS complex was selected automatically by the triangle character in ECG, and then it was time-reversed after removing its direct current component. Secondly, matched filtering was implemented at low computational cost by finite impulse response, which further enhanced QRS complex and attenuated non-QRS regions containing P-wave, T-wave and various noise components. Subsequently, triangle structure-based threshold decision was processed to detect QRS complexes. And RR intervals and triangle structures were further analyzed for the reduction of false-positive and false-negative detections. Finally, the performance of the proposed algorithm was tested on all 48 records of the MIT-BIH Arrhythmia Database. The results demonstrated that the detection rate reached 99.62?%, the sensitivity got 99.78?%, and the positive prediction was 99.85?%. In addition, the proposed method was able to identify QRS complexes reliably even under the condition of poor signal quality.     

Development of robust,fast and efficient QRS complex detector: a methodological review

The basis and reliability for timely diagnosis of cardiovascular diseases depend on the robust and accurate detection of QRS complexes along with the fiducial points in the electrocardiogram (ECG) signal. Despite, the several QRS detection algorithms reported in the literature, the development of an efficient QRS detector remains a challenge in the clinical environment. Therefore, this article summarizes the performance analysis of various QRS detection techniques depending upon three assessment factors which include robustness to noise, computational load, and sensitivity validated on the benchmark MIT-BIH arrhythmia database. Moreover, the limitations of these algorithms are discussed and compared with the standard signal processing algorithms, followed by the future suggestions to develop a reliable and efficient QRS methodology. Further, the suggested method can be implemented on suitable hardware platforms to develop smart health monitoring systems for continuous and long-term ECG assessment for real-time applications.     

高频稳态噪声对心血管系统影响的调查

目的 观察高频稳态噪声对心血管系统的影响。方法 测量噪声作业女工的血压、心率、心律、QRS间期、ST段改变、Q—T间期等参数。结果 工龄小于15年的噪声组窦性心动过速、窦性心律不齐、束支传导阻滞与对照组比较差异有显著性，血压升高及其他心电图参数变化不明显；工龄大于和等于15年噪声组窦性心动过缓，血压升高、QRS时间延长、ST段改变、Q—T间期延长、左心室高电压与对照组比较差异有显著性。结论 接触高频稳态噪声可对心血管系统产生不良影响，影响的范围和程度与接触时间有关。     

Specific features of QRS-complex identification algorithms for real-time ECG systems

The paper reviews the existing methods for identifying QRS complexes. An attempt is made to make a well-defined classification of available algorithms in an approach to QRS detection. Emphasis is laid on the consideration of specific requirements for such algorithms by computer-aided real-time ECG systems. A task of choice of the most suitable method is formulated. An algorithm based on the well-known principles of frequency-time detection is proposed as an alternative solution of this task. The algorithm makes it possible to single out QRS complexes from real-time ECG and to effectively make a digital signal processing by available optimized libraries. The method initially used in the Matlab package has been integrated within the laboratory computerized ECG system.     

以心率和心率变异性为指标的疲劳分析系统

从心电信号中提取心率(HR)和心率变异性(HRV),并对其5项时频域指标进行分析。实验结果发现:疲劳后,HRV时域测量指标中的正常R-R间期的标准差(SDNN)明显上升,HRV频域测量指标中的总功率值TP明显上升,低频段功率值LF明显上升,高频段功率值HF明显下降,LF与HF的比值LF/HF明显上升。并根据其上升与下降的速率的不同划分疲劳等级。因而,采用此5项心电图时频域指标,可以对疲劳程度进行定量化的反映和评价。     

论心电信号检测中的噪声与干扰及其消除方法

目的：认识心电信号是从体表检测到的心脏电生理信号,它对心脏疾病的诊断意义重大。方法：强调在心电信号检测过程中,很容易受到噪声（干扰）的影响,如随机噪声、工频干扰、检测系统的内部噪声等。结果：分析了心电检测中各种噪声和干扰产生的原因及消除和减小噪声（干扰）的方法。结论：为了尽可能地消除噪声（干扰）,又不使检测到的心电信号失真,这就需要改进采集电路、滤波电路,运用新的运算方法。     

二次微分小波在心电图QRS波检测中的应用

叙述将小波变换应用于ECG信号检测QRS波。利用二进Marr小波对信号按Mallat算法进行变换;从等效滤波器的角度分析了信号奇异点（R波峰值点）与其小波变换模极大值的关系;探讨了二次微分小波与一次微分小波在奇异点分析时性能上的差异。在检测中运用了一系列策略以增强算法的抗干扰能力,提高QRS波的正确检测率。经MIT／BIH标准心律失常数据库验证,QRS波的正确检测率高达99．8％。     

12导联同步心电信号自动检测技术的研究

论述基于ＰＣ机的标准十二导联同步心电图自动检测系统的构成，本系统软件采用Ｗｉｎｄｏｗｓ开发平台面向对象的程序设计方法，从整体结构上分析实现ＱＲＳ复合波、Ｐ波、Ｔ波以及ＳＴ段的检测，实现心电信号的自动分析。内容涉及心电信号预处理技术、波形特征参数检测技术和波形模式识别技术，介绍小波变换在波形特征点识别中的应用方法。     

应用小波变换模极大值检测ECG特征点

利用小波变换模极大值对ECG信号进行奇异性检测，提取ECG信号P波、T波和QRS波群的特征点，具有定位准确，检出率高的特点。实验中选用Mexicanhat连续小波算法，应用MATLAB6．5对MIT-BIH心电数据库的数据进行处理，证实了算法的有效性和可靠性。     

基于LabVIEW的心电信号读取及处理分析

LabVIEW在仪器设计中的优势已越来越明显。本文在软件平台上利用LabVIEW输入MIT库中的心电信号，将其依次进行陷波、高通、低通等滤波处理，分析、计算出心率和QRS波的振幅及间期，实现了虚拟仪器中信号的分析处理任务。     

创新Ⅰ导联左耳与右上肢连接方式对QRS波群的影响

目的：探讨创新Ⅰ导联左耳与右上肢连接方式对QRS波群的影响。方法：选择2009年8月-2012年5月在笔者所在医院心电图室接受常规心电图检查的门诊和住院患者以及健康体检者共110例,每位受检者记录一份常规十二导联心电图和创新Ⅰ导联左耳与右上肢连接方式心电图,经统计学处理后对QRS波群进行分析。结果：标准Ⅰ导联和aVL导联波形变化明显,Ⅱ、Ⅲ、aVF导联波形相同,aVL导联和aVR导联波形相近,具体表现为：（1）Ⅰ导联呈波形极小的“rs”型,且多数情况下r／s〈1,少数情况r／s=1,即呈等电位线;（2）Ⅱ导联QRS波群时限、形态、振幅、方向不变同标准连接图;（3）Ⅲ和aVF导联波形同Ⅱ导联,只是振幅较标准图形增高1．5～6．2mm;（4）aVL导联和aVR导联波形接近,且avL导联负向波振幅较aVR导联深;（5）胸前V1-6导联QRS波群时限、形态、方向与标准图形相同,只是振幅高低有微小差异,可以忽略不计;（6）额面平均心电轴男性（90．69±6．58）°,女性（89．98±7．51）°;（7）以上各导联的变化男女性别之间无明显差异。结论：创新Ⅰ导联左耳与右上肢连接方式与标准十二导联图形相比,对QRS波群有一定的影响,但孙心电图总体的诊断结果影响不大,可以作为左侧上肢无法安置电极时记录心电图的一种临时补救方法,同样可以为临床提供心电图辅助诊断依据。     

无线寻呼台微波作业人员心电图分析

对某无线寻呼台３２１例微波作业人员进行了心电图（ＥＣＧ）检查与分析。全部受测对象为现职连续６个月以上的寻呼电脑女性操作者（接触组），并以１０７例非接触微波的女性为对照组。结果表明：无线寻呼台电脑机前微波漏能功率密度为２０～５０ｍＷ／ｍ２，均未超标。寻呼台室外环境微波漏能功率密度为２２０～８８０ｍＷ／ｍ２，有一定的微波漏能。接触组ＥＣＧ的异常发生率为２７．７３％，对照组为１１．２１％，有非常显著性差异（Ｐ＜０．０１）。经分析发现接触组中窦性心律不齐发生率（１９．３６％）明显高于对照组（５．６０％），Ｐ＜０．０１；接触组Ｐ－Ｒ间期（０．１５５４±０．０２１１）ｍｓ较对照组（０．１４８±０．０２２７）ｍｓ延长，Ｐ＜０．０１。其余心率、ＱＲＳ间期、Ｑ－Ｔ间期的数值以及窦性心动过缓、窦性心动过速和心电轴左偏等发生率，两组之间均无差异（Ｐ＞０．０５）。结果提示：无线寻呼台电脑操作人员长期接触低强度微波，可导致机体植物神经功能紊乱，从而出现窦性心率不齐的改变。     

利用小波变换的方法检测心电信号的QT间期

主要介绍尝试一种新的方法对心电信号的QT间期进行检测。QT间期指心电波形中QRS波起点到T波终点这一段所对应的时间间隔,代表心室去极化过程。QT间期及其变异对于预测恶性心率失常具有一定准确性和临床意义。小波变换是一种信号的时间-尺度分析方法,它具有多分辨率的特点即对于信号的低频部分具有较高的频率分辨率和较低的时间分辨率,在信号高频部分具有较高的时间分辨率和较低的频率分辨率。根据QT间期起始点的特点选择高斯函数的二阶导数作为小波基,并用其对心电信号进行多尺度变换,观察结果选择QRS波起点、T波终点特征明显的波形作间期检测对象。将检测结果转化成校正QT间期—QTC,转化后可进一步评测间期长短,对疾病进行预测。     

A combined heart rate and movement sensor: proof of concept and preliminary testing study

OBJECTIVE: Heart rate monitoring has previously been used as a technique for measuring energy expenditure (EE) in field studies. However, the combination of heart rate monitoring with movement sensoring could have theoretical advantages compared to either method used alone. Therefore, this study was undertaken to develop and validate a new combined heart rate monitor and movement sensor instrument (HR+M) for measuring EE. METHODS: The HR+M instrument is a single-piece instrument worn around the chest which records minute-by-minute heart rate and movement. Eight subjects underwent an individual calibration in which EE and heart rate were measured at rest and during a sub-maximal bicycle ergometer test. They then wore the HR+M for 24 hours in a whole-body calorimeter and underwent a standard protocol including periods of physical activity and inactivity. Minute-by-minute heart rate was converted to EE using individual calibration curves with the motion data discriminating between periods of inactivity and activity at low heart rate levels. EE was also calculated using the HRFlex method which relies on heart rate alone. Both estimates of EE were compared to EE measured in the whole-body calorimeter. RESULTS: The mean percentage error of the HR+M method calculating TEE compared with the gold standard of the calorimeter measurement was 0.00% (95% CI of the mean error -0.25, 1. 25). The HRFlex method using the heart rate information alone resulted in a mean percentage error of 16.5% (95% CI of the mean error -0.57, 1.76). CONCLUSIONS: This preliminary test of HR+M demonstrates its ability to estimate EE and the pattern of EE and activity throughout the day. Further validation studies in free-living individuals are necessary. SPONSORSHIP: NJW is an MRC Clinician Scientist Fellow. KLR holds an MRC PhD scholarship.     

ECG changes in humans exposed to 50 Hz magnetic fields

Possible health issues of ELF EMFs include cardiovascular effects since both electrocardiogram and heart-rate changes have been reported in the literature. A non-linear relationship between field strength and biological response has been reported in some studies. In this study, a total of 59 subjects, divided into three independent magnetic field strength groups, were compared. A calculated 12-hour time weighted average (TWA) value of the fields was used as an exposure metric for each of the three locations ("low": 0.067 muT, "medium": 1.18 muT and "high": 5.2 muT) and subsequently used to estimate workers' exposure at these sites. Electrocardiograms were recorded in the resting position. Five parameters were derived from the ECG: heart rate (HR), duration of P wave and QRS wave, and duration of PR and QT intervals. The QT intervals were normalized to a heart rate of 60 (QTc). The obtained data were analyzed first by means of multivariate analysis of covariance and then oneway univariate analyses of covariances (ANCOVA) using exposure duration as a covariate. Only the ANCOVA on the QTc interval was significant. Our results suggest that the relationship between field strength and response is non-linear: the adjusted mean QTc values are similar between the "low" and the "high" group, but significantly lower in the "medium" group. One possible interpretation of our results is that a specific exposure pattern might be responsible for the non-linear effects observed, so that generally, characterizing exposure to electric and magnetic fields using simple metrics such as TWA may be insufficient.     

基于短时傅里叶变换的胎心音瞬时心率检测算法

目的：针对母亲的活动和胎儿在子宫内的活动都会导致胎心音信号的幅度出现较大波动,传统自相关算法难以准确测量胎儿瞬时心率的问题,提出一种基于短时傅里叶变换的胎心音瞬时心率检测新方法,．方法：对胎心音进行短时傅里叶变换,从二维时频图中提取出胎心音特征模板并与目标图像进行归一化互相关匹配,绘制出互相关曲线,根据互相关曲线中的相邻峰值点时间间隔,计算出胎儿的瞬时心率。结果：实验结果表明,该算法的识别准确率比传统算法高5％。结论：该算法克服了胎心音易受噪声干扰的弱点,实现了胎心音瞬时心率的计算,而且还提高了胎心率计算的准确性,为胎心音波形分析和胎心率监护提供了一种新的方法。     

Myocardial ischemia analysis based on electrocardiogram QRS complex

Electrocardiogram (ECG) is an economic, convenient, and non-invasive detecting tool in myocardial ischemia (MI), and its clinical appearance is mainly exhibited by the changes in ST–T complex. Recently, QRS complex characters were proposed to analyze MI by more and more researchers. In this paper, various QRS complex characters were extracted in ECG signals, and their relationship was analyzed systematically. As a result, these characters were divided into two groups, and there existed good relationship among them for each group, while the poor relationship between the groups. Then these QRS complex characters were applied for statistical analysis on MI, and five characters had significant differences after ECG recording verification, which were: QRS upward and downward slopes, transient heart rate, angle R and angle Q. On the other hand, these QRS complex characters were analyzed in frequency domain. Experimental results showed that the frequency features of RR interval series (Heart Rate Variability, HRV), and QRS barycenter sequence had significant differences between MI states and normal states. Moreover, QRS barycenter sequence performed better.     

十二导联心电图诊断线索对宽QRS波心动过速的临床价值

目的分析十二导联心电图诊断线索对宽QRS波心动过速（wide QRS complex tachycardia,WQRST）的临床价值,探索Ⅱ导联QRS波第1峰时限（R-wave peak time,RWPT）〉150ms和Ⅱ导联QRS波时限≥130ms对室性心动过速（ventricular Tachycardia,VT）和室上性心动过速（supraventricular tachycardia,SVT）的鉴别诊断意义。方法回顾性地分析就诊于黄冈市中心医院的198例WQRST（心率〉100次／min且QRS时限〉0．12s）患者。并经心脏电生理学检查明确诊断,记录并分析十二导联心电图对WQRST的鉴别诊断线索,记录所有十二导联心电图的Ⅱ导联QRS波第1峰时限及Ⅱ导联QRS波时限。结果区别VT和SVT的主要诊断线索有QRS波时限、QRS波心电轴、QRS波正负同向性、房室分离、室性融合波和心室夺获、胸前导联Rs是否缺失及时限、窦性心律时是否伴显性预激或同形态室性早搏、Vi／Vt≤1、V1和V6导联特殊形态学诊断标准等。除V1、V6负向一致性差异无统计学意义外,其余各个指标差异均有统计学意义（P〈0．05）,II导联RWPT≥50ms时能够较好地区分VT和SVT,敏感度和特异度分别为0．89、0．85。结论十二导联心电图是WQRST鉴别诊断的重要方法之一,在临床中应该灵活运用各种诊断线索。Ⅱ导联RWPT≥50ms能够作为区分VT和SVT一种简单实用的鉴别标准,用于重症监护室和急诊科等。     

职业性噪声对暴露人群外周血中去甲肾上腺素及心血管系统的影响

目的研究职业性噪声对作业工人血清中去甲肾上腺素（NE）含量以及相关心血管系统指标的影响。方法选取某企业接触职业性噪声的职工130人作为噪声暴露组,另选该企业不接触噪声和其他毒物的134名职工为对照组,抽取空腹静脉血,采用酶联免疫法（ELISA）测定其外周血中NE的含量,按照《职业健康监护管理办法》进行职业性噪声暴露人群的健康检查。结果暴露组和对照组的NE含量分别为（0．1387±0．099）ng／ml和（0．1019±0．080）ng／ml,差异有统计学意义（P〈0．05）;血压、心率以及心电图异常的检出率差异也有统计学意义（P〈0．05）。结论职业性噪声可引起暴露人群外周血中NE含量的升高,并可能通过此途径对心血管系统产生影响。