信号平均心电图的应用现状

信号平均心电图(SAECG)是把微弱电信号进行叠加、平均以突出重复出现的、有规律的心电信号同时降低随机性的噪声的一种特殊心电图,主要用于检测常规体表心电图无法显示出来的微弱高频电位。1971年这种技术首先用于体表希氏束电位检测。1978年Fontaine在临床室速病人用信号平均技术记录到低振幅、碎裂的心室晚电位。此后SAECG又用于检测心房晚电位。随着心内电生理检查技术的日益成熟及在临床的推广使用,体表希氏束电图的地位迅速下降,目前已不认为是一项有意义的检查。目前SAECG主要用于检测心室晚电位。心室晚电位极少在正常人群中…     

24小时动态心电图对冠心病的诊断价值

对41例胸痛患者进行24小时动态心电图(AECG)及冠状动脉造影检查,其中24例在作上述检查2—3周内进行平板运动试验。10例正常冠状动脉患者AECG显示心肌缺血者仅1例,特异性90％;冠状动脉病变31例中显示心肌缺血20例,敏感性65％。心肌缺血检出敏感性与冠状动脉病变程度有关,多支病变为78％,单支病变为46％(P<0.01).AECG对单支病变患者,心肌缺血检出率明显低于平板运动试验(P<0.01);对多支病变患者,心肌缺血检出率与平板运动试验相同,均为88％。     

信号平均心电图与非缺血性室性心动过速

信号平均心电图与非缺血性室性心动过速黄震华综述徐济民审校信号平均心电图（ＳＡＥＣＧ）检测心室晚电位对于心肌梗死病人的预后估测、冠心病患者心血管事件和猝死危险性测定有重要意义。最近研究表明信号平均心电图和心室晚电位对各种非缺血性心脏病引起的室性心律失常...     

动态心电图对隐性冠心病的诊断价值

隐性冠心病是指在病理解剖上冠状动脉已有病变，临床上患者常无心绞痛，或其它心脏病方面的表现(亦称无症状心肌缺血)，但有心肌缺血的客观依据：如典型心肌缺血的ST段及T波异常变化的心电图。无症状心肌缺血是冠心病的一种特殊类型．由于无症状常被患者及医务人员忽视．严重者可发生心肌梗死及致命心律失常而猝死，对此已引起国内外学者的特别关注。     

动态心电图对冠心病无症状性心肌缺血的诊断价值

作者应用动态心电图检测110例冠心病患者,结果发生缺血性ST段下移386次,其中无症状性心肌缺血(SMI)291次,占缺血总数75%。SMI发作时心率平均65±14.5次/分,有症状性心肌缺血(MI)发作时心率79.2±5.6次/分,两组比较有显著性差异。SMI发作频率以上午6～9时最高,占24小时发作总数的30%,而夜间10时～凌晨1时发作频率最低,占24小时发作总数的7%。提示动态心电图为诊断冠心病SMI的有效方法。     

信号平均心电图正常值调查

本文对104名正常人进行信号平均心电图检测。各参数正常值为:ORS_T:75～112ms;LAS 40≤39ms,有年龄差异;RMS_(40)≥19μV。     

高频心电图对冠心病诊断的探讨

高频心电图（ＨＦＥＣＧ）是一种无创伤性的诊断技术,易为病人所接受,不少文献报道,ＨＦＥＣＧ对冠心病诊断的敏感性和特异性都很高。为探讨ＨＦＥＣＧ在冠心病诊断方面的临床意义,本文就冠心病和非冠心病患者ＨＦＥＣＧ改变进行比较和分析,现报道如下。１　资料和方法１．１　病例选择　按世界卫生组织专家委员会拟定的冠心病诊断标准,检测住院和门诊病人共２２６例,分为冠心病组和非冠心组,其中冠心病组共１４４例,年龄５０～８４岁,平均７０－６岁;非冠心病组共８２例,年龄５０～８３岁,平均６１－７岁。１．２　方法　采用…     

动态心电图对冠心病心肌缺血的诊断价值

目的：参照冠状动脉造影，观察动态心电图(Holter)对冠心病心肌缺血的诊断价值。方法：选择76例曾作冠状动脉造影的患者，分析其Holter的缺血性ST段改变。结果：Holter与冠状动脉造影的诊断符合率为51.3％，其诊断冠心病的敏感性为36.5％，特异性为82.5％。多支病变及严重狭窄的冠心病可提高Holter的敏感性。结论：Holter对冠心病的诊断特异性高，而敏感性较低，多支冠脉狭窄及严重可提高其敏感性。     

高频心电图诊断冠心病的价值观察

分析81例有冠状动脉造影(CAG)资料对照的高频心电图(HFECG)检测结果,CAG阳性组和阴性组的高频切迹数分别为9.9±3.2和5.9±3.6个,HFECG诊断冠心病的敏感性和特异性分别为80.6％和76.0％。对于无心肌梗塞的冠心病的早期诊断,其敏感性亦高于常规ECG和DCG,与单光子发射断层扫描SPECT相似;而特异性则与上述3项无创性检查均相似。切迹数及其分布导联数与冠脉阻塞支数无明显关系。     

高频心电图对冠心病的判别作用研究

为探讨高频心电图对冠心病的判别作用，采用Ｂａｙｅｓ方法分析９３例冠心病率患者和７７例正常人体表１２导联的高频切迹。结果显示：除Ｉ和Ｖ２导联外，其余１０个导联的高频切迹对冠心病和正常人具有明显的判别作用。     

动态心电图在冠心病心律失常诊断中的应用观察

目的探讨动态心电图在冠心病心律失常诊断中的应用价值。 方法回顾性分析2016年3月至2018年3月胶州市人民医院收治的70例冠心病患者的临床资料,所有患者均经冠状动脉造影确诊,检查前均接受常规心电图与动态心电图检查,对比两种检查方式对心肌缺血与心律失常(房性心律失常、室性心律失常、房室传导阻滞、矩阵室上速等)的检出率。 结果70例冠心病患者中,常规心电图检查显示心肌缺血阳性检出率为80.00%(56/70),低于动态心电图检查92.86%(65/70),差异有统计学意义(P<0.05)。动态心电图房性心律失常、室性心律失常、房室传导阻滞、矩阵室上速阳性检出率高于常规心电图,差异有统计学意义(P<0.05)。 结论动态心电图可提高冠心病心律失常的检出率,为疾病评估与预后判断提供丰富而详细的影像与数据。     

Effects of tilt and exercise on signal-averaged electrocardiogram after acute myocardial infarction

To determine whether enhanced sympathetic activity could altera non-invasive index of cardiac instability, we analysed theeffects of 90° head-up tilt and submaximal exercise stresstest on high amplification signal-averaged electrocardiogramin 64 patients after acute myocardial infarction. At rest, ventricularlate potentials were detected in 25% of patients, characterizedby a significant prolongation of filtered QRS complex (137 ±3vs 115 ±2 ms) and of its components smaller than 40 fiV(38 ±2 vs 16 ±1 ms), as well as by a reduced rootmean square voltage calculated for the terminal 40 ms of QRScomplex (RMS40 voltage) (19 ± 1 vs 75 ± 9µV)in comparison to patients without micropotentials. Sympathetic activation induced by tilt caused a significantincrease in heart rate (from 67 ±3 to 79 ±3 beatsmin^–1) but did not modify either the incidence of ventricularlate potentials or the values of any of the signal-averagedelectrocardiogram parameters considered. In 19 patients, recordingswere also obtained during a submaximal bicycle exercise stresstest at a heart rate of 114 ±4 beats min^–1 andwith systolic arterial blood pressure at 153 ±6 mmHg.No effect on signal-averaged electrocardiogram parameters wasdetectable during this experimental intervention. These data indicate that after myocardial infarction, sympatheticactivation does not seem to modify signal-averaged electrocardiogramparameters.     

心电图踏车试验时ST段定量分析对冠心病早期诊断的再探讨

对经冠状动脉造影确诊的冠心病心绞痛患者的心电图踏车试验(BET)过程中.ST段的定量分析发现①ST段水平型或下斜型_F移≥0.35ram(P<0.05),即可提示冠心病的存在。⑦当ST段的变化<1mm时,其与冠状动脉病变的程度无相关性。③ST段变化的导联位置和数目与冠状动脉病变的部位和支数无明显关系。本研究表明.以ST段水平型或下斜型下移≥0.35mm为标准,可以提高BET诊断冠心病的敏感性。井且有较高的特异性。     

Effects of exposure to hypoxia on the signal-averaged electrocardiogram in healthy subjects

The effects of hypoxia on the signal-averaged ECG (SAECG) wereinvestigated in 26 healthy active subjects with no suggestionof cardiac disease. The SAECG was recorded in each resting subjectin normoxic and hypoxic normobaric conditions (inspired O₂ fraction20.7 vs 10.0%) which lowered resting arterial O₂ saturationfrom 98.6 +0.6% to 77.7 ± 8%. Recordings from four subjects(three men) met the definition of abnormal late potentials atbaseline; in all these subjects but one, who exhibited an improvedbut still abnormal QRS duration, these parameters returned tonormal in hypoxic conditions. The duration of the filtered QRSwas significantly reduced (from 107.6 ±13.2 to 101.6± 11.3 ms, P<001), the duration of the low amplitudesignals in the terminal portion of the QRS <40 µ V(LAS) significantly decreased (from 26.5 ± 9.5 to 22.7± 7.9 ms, P<005) and the root mean square voltagein the last 40 ms (Term-RMS) increased non-significantly (from55.8±40.2 to 69.1±38.3 µV, P=0.058). Hypoxiadetermined a higher (P<0.05) heart rate increase in subjectswith abnormal records than in normal subjects. These data could be related to a sympathic discharge. They suggestthat: (1) variation in heart rate could affect the SAECG; (2)exposure to hypoxia improves SAECG parameters in healthy subjects,possibly related to sympathetic discharge; (3) abnormal recordscollected during sinus bradycardia could represent a type offalse-positive expression of late potentials in young activeadults.     

Flecainide-related alterations in the signal-averaged electrocardiogram: similarity between patients with or without ventricular tachycardia.

The signal-averaged electrocardiogram (SAECG) identifies patients at risk of sustained ventricular tachycardia (VT), but the influence of anti-arrhythmic agents on the SAECG is not yet established. We have evaluated the effects of flecainide on the SAECG (XYZ leads, high-pass filters 25 Hz and 40 Hz, noise level 0.2 microV-0.4 microV, Model 1200 EPX, ART) in 25 patients: 15 (VT group) had documented sustained VT (nine post-MI, two dilated cardiomyopathy, four normal hearts) and 10 (control group) had supraventricular arrhythmias and structurally normal hearts. The SAECG was recorded in all patients prior to, and 5 min following a flecainide infusion (2 mg.kg-1 over 10 min). Before flecainide administration an abnormal SAECG was recorded in six patients from the VT group and in no control patient. Following flecainide, 13 patients from the VT group and eight control subjects demonstrated abnormal SAECG. Flecainide produced similar significant percentage changes in all SAECG indices in both the VT and control groups: total QRS duration was prolonged by 26.0 +/- 10.4% vs 26.7 +/- 15.7%, late potential duration under 40 microV was prolonged by 55.5 +/- 62.0% vs 106.1 +/- 61.4%, and the root mean square voltage of the last 40 ms of the QRS was reduced by 42.1 +/- 34.9% vs 55.3 +/- 24.4%, respectively. We conclude that flecainide significantly changes the SAECG parameters in patients with and without a history of VT, irrespective of the underlying disease.     

静息心电图在诊断冠状动脉病变中的作用

目的探讨常规12导联心电图指标对静息状态下冠状动脉病变的预测价值。方法回顾性分析1998年3月～2006年1月拟诊不稳定型心绞痛并行冠状动脉造影患者（104例）的造影资料及冠脉造影前心电图。以左主干、前降支、回旋支、右冠状动脉中任一支狭窄≥50％者为阳性，将患者分为阴性组（8例）、单支病变组（41例）、双支病变组（25例）、三支病变组（16例）、左主干病变组（14例，可合并单支、双支或三支病变）。各组病例的年龄、性别、化验检查等指标进行统计学分析；计数各组病例心电图aVR导联ST段抬高病例数、异常导联数、ST段移位绝对值之和、异常导联数＋ST段移位绝对值之和、ST段时间，在单支病变组、双支病变组、三支病变组和左主干组之间进行统计学分析。结果①年龄：单支病变组与左主干病变组比较有显著性差异（P〈0.05），其它各组间比较无显著性差异（p〉0．05）。（参avR导联ST段抬高、异常导联数、ST移位、异常导联＋ST段移位：单支病变组与三支病变组、左主干病变组之间比较有显著性差异（P〈0．05）；ST段改变时间：单支病变组与左主干病变组之间比较有显著性差异（p〈0.05），但与三支病变组比较无显著性差异（P〉0．05）。③aVR导联抬高、ST段移位、异常导联＋ST段移位：双支病变组与三支病变组、左主干组比较有显著性差异（p〈0．05）；异常导联，双支病变组与三支病变组、左主干病变组比较无显著性差异（p〉0．05）；ST段时间：双支病变组与左主干病变组比较有显著性差异（p〈0．05），而与三支病变组比较无显著性差异（p〉0．05）。结论aVR导联抬高、ST段移位、异常导联＋ST段移位是识别单支病变或双支病变与三支病变或左主干病变的敏感指标；ST段时间是识别单支病变或双支病变与左主干病变的敏感指标，但对识别三支病变不敏感；异常导联数对识别单支病变与三支病变或左主干病变敏感，但对识别双支病变与三支病变或左主干病变不敏感。     

老年冠心病患者心律失常的动态心电图特点及其临床意义

对192例老年冠心病患者和180例中年冠心病患者的动态心电图对比分析后发现。老年组除白天最慢心率外,其余各项心率均低于中年组(P<0.05)。老年组各种心律失常的总发生率,尤其是复杂心律失常的发生率明显高于中年组(P<0.005)。伴有心肌缺血和左室功能障碍的患者。其室性心律失常的总发生率和Ⅲ级以上室性心律失常的发生率明显高于无心肌缺血和左室功能正常的患者(P<0.005)。     

三种无创性检查方法诊断冠心病的评价

作者以冠状动脉造影（ＣＡＧ）检查为金标准，１２７例病人以冠心病收入院，行ＣＡＧ检查，并行心电图（ＥＣＧ）、心脏Ｂ超和心肌灌注断层显像等无创伤检查，对其诊断效能进行评价。结果显示:ＥＣＧ，心脏Ｂ超和心肌灌注断层显像的敏感度分别为６０．３％、７０．９％和９０．５％，特异度分别为５４．７％、６２．３％和２１．４％；准确度分别为５７．５％、６６．７％和６２．９％。ＥＣＧ和心脏Ｂ超联合试验可使敏感度提高到７８．２％，特异度提高到８３．０％。心肌灌注显像的特异度较低，但对ＣＡＧ不能检出冠状动脉的微血管病变而心肌灌注显像对此类病人的敏感度却较高。心脏Ｂ超检出的舒张期功能障碍特别是同时合并节段性室壁运动异常对冠心病的诊断具有重要意义。