心得安食管心房超速负荷试验中QTd诊断冠心病的价值

目的 :观察患者食管心房超速负荷试验 （TRAS- ECG）及心得安食管心房超速负荷试验 （TRAS- Prop- ECG ）前后心电图校正 QT间期 （QTc）及 QT间期离散度 （QTd）的变化 ,以评价 TRAS- Prop- ECG诊断冠心病的价值。方法 :对 5 0例冠心病 （CHD）患者 （CHD组 ）及 30例正常者 （对照组 ）进行 TRAS- ECG和 TRAS- Prop- ECG试验 ,记录试验前后 12导联同步心电图 ,测量其 QTc及 QTd,根据分布曲线求出 QTc及 QTd的截断点。分别计算两种试验的敏感度、特异度及准确度。结果 :如以 QTd≥ 4 0 ms为截断点 ,以 TRAS- ECG诊断 CHD时 ,其敏感度、特异度及准确度分别为 76 %、6 7%、73% ;以 TRAS- Prop- ECG诊断 CHD时 ,其敏感度、特异度及准确度分别为 92 %、93%、93%。结论 :TRAS- Prop- ECG时 ,如以 QTd≥ 4 0 ms为截断点 ,可明显提高其诊断的敏感度、特异度及准确度。QTd≥ 4 0 ms可作为 TRAS- Prop- ECG诊断 CHD的一项重要参考指标。     

潘生丁负荷试验中QTd诊断冠心病的价值

目的 :观察冠心病患者潘生丁试验 （DP- ECG）及潘生丁食管心房调搏复合试验 （TRAS- DP- ECG）前、后心电图 ST段、校正 QT间期 （QTc）及 QT间期离散度 （QTd）的变化 ,以评价 TRAS- DP- ECG诊断冠心病的价值。方法 :对 5 0例冠心病 （CHD）患者 （CHD组 ）及 30例正常者 （对照组 ）进行 DP- ECG和 TRAS- DP- ECG,记录试验前后 12导联同步心电图 ,测量其 ST段 ,QTc及 QTd。根据分布曲线求出 QTc及 QTd的截断点。分别计算两种试验的敏感度、特异度及准确度。结果 :如以 QTd≥ 40 m s为截断点 ,以 DP- ECG诊断 CHD时 ,其敏感度、特异度、准确度分别为 76 % ,93% ,82 % ;以 TRAS- DP- ECG诊断 CHD时 ,其敏感度、特异度、准确度分别为 92 % ,93% ,92 %。结论 :TRAS- DP- ECG时 ,如以 QTd≥ 40 m s为截断点 ,可明显提高其诊断的敏感度及准确度而不影响其特异度。 QTd≥40 m s可作为 TRAS- DP- ECG时诊断 CHD的一项重要参考指标     

潘生丁试验中QT间期离散度增加对冠心病诊断价值的探讨

目的观察冠心病患者潘生丁试验前后心电图ST段、校正QT间期(QTc)及QT间期离散度(QTd)的变化,以探讨潘生丁试验时诊断冠心病的更敏感及特异的指标。方法对30例冠心病患者(冠心病组)及32例正常者(对照组)进行潘生丁试验,记录试验前后12导联同步心电图,测量其ST段,QTc及QTd的改变。根据受试者作业特征曲线(ROC曲线)求出QTc及QTd的阳性分界点,结合传统诊断标准ST段下移≥0．1mV,分别计算其特异性及敏感性。并与“并联诊断”方法进行比较。结果以潘生丁试验诊断冠心病时,如分别以ST段下移≥0．1mv、QTc≥440ms、QTd≥40ms为标准,其特异性分别为100％、68．8％、93．8％;敏感性分别为53．3％、83．3％和87．6％。如采用“并联诊断”方法,分别以ST段下移≥0．1mV和QTc≥440ms、ST段下移≥0．1mV和QTd≥40ms、QTc≥440ms和QTd≥40ms为标准,其特异性分别为68．8％、93．8％、68．8％。敏感性分别为70．0％、96．8％、90．0％。结论在潘生丁试验时,如以传统的诊断标准(ST段下移≥0．1mV),结合QTd≥40ms,可明显提高其诊断的敏感性而不影响其特异性,QTd≥40ms可作为潘生丁试验时诊断冠心病的一项重要参考指标。     

经食道心房调搏后QT离散度的变化在诊断冠心病中的价值

目的 研究经食道心房调搏后QT离散度的变化在诊断冠心病的中价值.方法 按世界卫生组织冠心病的诊断标准,选取住院患者58人做为观察对象,同期选取健康人30人做为对照组,两组均经食道心房调搏心脏负荷试验,当达到负荷心率或出现心绞痛,ST段下移≥0.1mv,停止试验,并于调搏前和调搏后做同步12导联体表心电图,走纸速度为50mm/s,并测量其QT离散度.结果 观察组调搏前后QT离散度有明显变化(P<0.01),而对照组变化不明显(P>0.01),如以QTd≥60ms做为临界值诊断冠心病,其敏感性为89.6%,特异性为93.3%.结论 以QTd≥60ms做为标准,经食道心房调搏诊断冠心病是一可靠的指标.     

平板运动试验QTd、QTcd、JTd对老年冠心病的诊断价值

QT离散度（QTd）预测严重室性心律失常和心源性猝死的价值已得到公认。文献报道冠心病患者QTd明显增大。近年来，QTc（用心率校正的QT间期）延长及QTd增大的临床意义不断受到重视。但对于老年冠心病患者报道较少。本文通过对38例明确诊断冠心病的老年患者行运动试验，对比其运动前后的QTd、QTc、JTd的变化，以比较其对冠心病的诊断价值。     

急诊经皮冠状动脉介入治疗对QT间期离散度的影响

目的探讨急诊经皮冠状动脉介入治疗（PCI）后对QT间期离散度（QTd）的影响。方法对70例ST段抬高的急性心肌梗死（AMI）患者行急诊PCI前和PCI后24h内12导联同步心电图QT间期、校正QT间期（QTc）、QTd及校正QT间期离散度（QTcd）4项指标进行对比分析。并监测严重心律失常发生情况。结果PCI后QT和QTc与术前差异无显著性,而QTd和QTcd则较术前明显减少,差异有显著性意义（P<0.01）。28例术前有恶性心律失常,其QTd明显高于无心律失常的患者[（70±18）msvs（52±15）ms,P<0.01];术后QTd降至（45±16）ms（P<0.01）,室性心律失常消失或减少。结论急诊PCI能显著减少AMI患者的QTd和QTcd,降低急性期恶性心律失常的发生。     

运动负荷试验中心电图QT离散度和缺血性ST段下移对冠心病的诊断价值

目的 分析心电图平板运动负荷试验中QT离散度(QTd)及ST段变化对冠心病的诊断价值。方法 观察158例经冠状动脉造影诊断为冠心病的患者及96例平板运动试验阴性的健康者QTd与ST段的变化。结果 冠心病组较对照组QTd明显延长(P<0.05),其延长程度与心电图ST段压低程度相关,QTd≥60ms对冠心病诊断的准确性优于传统的ST段诊断标准。结论 心电图平板运动试验QT离散度的变化可成为临床诊断及治疗冠心病的新指标。     

活动平板运动试验QT离散度对冠心病诊断的意义

目的:探讨活动平板运动试验的QT离散度对冠心病诊断的意义.方法:30例正常人和27例冠心病人进行活动平板运动试验,测定运动前和运动高峰的QT离散度(QTd)及校正QT离散度(QTcd).结果:正常人群运动前后QTd及QTcd无差别,而冠心病患者运动后QTd和QTcd较运动前明显增大.结论:运动后QT离散度增大是反映冠心病心肌缺血的重要指标,运动后QTd、QTcd增大结合ST段偏移可增加对冠心病诊断的敏感性.     

活动平板运动试验QT离散度对冠心病诊断的意义

目的：探讨活动平板运动试验的QT离散度对冠心病诊断的意义。方法：30例正常人和27例冠心病人进行活动平板运动试验,测定运动前和运动高峰和QT离散度（QTd)及校正QT离散度（QTcd)。结果：正常人群运动前后QTd及QTcd无差别,而冠心病患运动后QTd和QTcd较运动前明显增大。结论：运动后QT离散度增大是反映冠心病心肌缺血的重要指标,运动后QTd,QTcd增大结合ST段偏移可增加对冠心病诊断的敏感性。     

平板运动试验中校正的QT间期离散度及ST段下移对冠心病诊断价值的对比研究

目的 :比较运动试验中校正的QT间期离散度 (QTcd)与ST段下移标准对冠心病的诊断价值。　　方法 :选择 89例运动试验同期完成冠状动脉造影患者 ,将其分为冠状动脉造影阴性组 (n =63 )、冠状动脉造影阳性组 (n =2 6)。分别测量缺血型ST段下移的最大值及运动后QTcd值。使用SPSS软件包绘制受试者工作特征 (ROC)曲线。　　结果 :与ST段下移标准比较 ,QTcd≥ 5 0ms诊断冠心病的特异度较高 (68 2 5 %vs 80 95 % ,P <0 0 5 ) ,而敏感度较低 (76 92 %vs 61 5 4% ,P <0 0 5 ) ,但两种方法ROC曲线下的面积无统计学差异 (0 85 6vs 0 899,P >0 0 5 )。　　结论 :运动试验中QTcd与ST段下移标准对冠心病的诊断价值相当。     

食管心房调搏负荷试验联合平板运动试验对男性冠心病患者的诊断价值

目的 探讨食管心房调搏负荷试验联合平板运动试验对男性冠心病患者的诊断价值.方法 选择拟诊冠心病的男性患者82例,入选病例全部行冠状动脉造影,且造影前或后1个月行食管心房调搏负荷试验和平板运动试验,观察对比直径法确定的冠状动脉狭窄程度和范围与食管心房调搏负荷试验和平板运动试验结果.结果 以冠状动脉造影结果为标准,食管心房调搏负荷试验联合平板运动试验诊断冠心病的敏感度为72.9％,特异度为52.6％,阳性预测价值为90.4％,阴性预测价值为78.7％,食管心房调搏负荷试验及平板运动试验显示冠状动脉狭窄支数越多,ST段压低出现越早、压低程度越大、持续时间越长（P＜0.001）.冠状动脉造影阳性而食管心房调搏负荷试验、平板运动试验阴性者,多为单支病变或病变较轻.结论 简便易行且无创的食管心房调搏负荷试验联合平板运动试验能提高冠心病的诊断率,并可初步估测冠状动脉狭窄程度.     

U波异常有助诊断缺血性心脏病—冠脉造影与心电图对照

目的 探讨U波异常在诊断缺血性心脏病中的价值。方法 选择临床拟为冠心病的男性患者52例，排除电解质紊乱，应用常规心电图、运动负荷心电图及冠脉造影，分析ST段缺血性改变、U波异常在诊断缺血性心脏病中的敏感性和特异性。结果 52例临床拟诊冠心病患者，冠脉造影阳性者38例。冠脉造影阳性者中，常规心电图ST段呈缺血性改变者16例，U波异常者8例，其诊断缺血性心脏病的灵敏度分别为42．11％、21．11％(16/38、8/38)；运动试验阳性者26例，运动诱发U波异常者15例，其诊断缺血性心脏病的灵敏度分别为68．42％、39．47％(26/38、15／38)。冠脉造影阴性者(n＝14)中，常规心电图ST段无缺血性改变6例，U波正常13例，特异度分别为42．86％、92．86％(6／14、13／14)5运动负荷时，结果 阴性9例，U波正常14例，特异度分别为64．29％、100％(9／14、14／14)。运动负荷时尚见2例单独U波异常，其冠脉造影证实有病理性狭窄。结论 U波异常在诊断缺血性心脏病中敏感性虽不如ST段下移的高，但U波异常的特异性高，尤其是运动诱发的U波异常更具诊断价值；缺血性U波异常有助诊断冠心病。     

心电图ST段压低、QTc、QTd及投影间夹角有助于判断慢性心力衰竭患者心脏同步化治疗的预后

目的:探讨心肌复极异常心电图对慢性心力衰竭（CHF）患者心脏再同步化治疗（CRT）预后的预测价值。方法：收集102例CHF且行CRT治疗患者的临床病历资料，术后随访3年，依据随访终点情况分为死亡组25例和存活组77例。CRT术前完善所有患者心电图及心脏彩超，比较2组患者ST段压低、QTc、QTd、投影间夹角（TMD）及QRS波时限情况；采用多因素Logistic回归分析影响CHF患者CRT治疗预后的因素；绘制心电图指标对CHF患者预后的受试者工作特征（ROC）曲线，判断心电图ST段压低、QTc、QTd及TMD对CHF患者CRT治疗预后的预测价值。结果：2组的病程、纽约心脏协会（NYHA）分级、并发心房颤动、左室射血分数(LVEF)、左心室内径（LVD）及左心房内径（LAD）比较，差异有统计学意义（P均＜0.05）；死亡组病例心电图具有明显更高的ST段压低、QTc、QTd及TMD（P均<0.05）。多因素Logistic回归分析可知，NYHA分级、心房颤动、ST段压低、QTc、QTd、TMD、LVEF、LVD及LAD均是CHF患者CRT治疗预后的独立危险因素。ROC曲线显示，TMD具有最大的预测效能，其曲线下面积（AUC）为0.839，约登指数为0.61；其次为QTd，AUC为0.817，约登指数为0.44；ST段压低的AUC为0.748，约登指数为0.41；最低为QTc，AUC为0.724，约登指数为0.36。结论：心电复极参数ST段压低、QTc、QTd及TMD异常增加均提示CHF患者CRT治疗预后效果较差。     

Extent and severity of coronary heart disease. Determinations by thallous chloride Tl 201 myocardial perfusion scanning and comparison with stress electrocardiography.

Rest and exercise ECGs are the most widely used "noninvasive" tests for detecting coronary heart disease, but their sensitivity and specificity are suboptimal. Therefore, the diagnostic value of myocardial perfusion scanning using thallous chloride Tl 201 during rest and stress electrocardiography was examined in 95 patients with a chest discomfort syndrome. Overall, thallous chloride Tl 201 perfusion scanning had a sensitivity of 75% and a specificity of 91% for coronary heart disease compared with 56% sensitivity and 86% specificity with exercise-induced ST segment depression on the ECG. Combining rest and stress ECGs resulted in a sensitivity of 71%. In patients with coronary heart disease, perfusion scanning had a sensitivity of 93% for asynergy compared with 58% for exercise-induced ECG ST depression. Rest and stress myocardial perfusion scanning with thallous chloride Tl 201 provides improved sensitivity with good specificity in the diagnosis of coronary heart disease compared with exercise electrocardiography alone.     

Heart rate adjustment of the time-voltage ST segment integral: identification of coronary disease and relation to standard and heart rate-adjusted ST segment depression criteria

To assess the effect of heart rate adjustment of the magnitude of the ST integral (ST-HR integral) on exercise test performance, the exercise electrocardiogram (ECG) of 50 clinically normal subjects and 100 patients with known or suspected coronary artery disease was analyzed. At matched specificity of 96% with standard ECG criteria (greater than or equal to 0.1 mV of additional horizontal or downsloping ST segment depression), an unadjusted ST integral partition of 16 microV-s identified coronary disease in the 100 patients with known or suspected disease with a sensitivity of only 41%, a value significantly lower than the 59% sensitivity of standard ECG criteria (p less than 0.01) and the 65% sensitivity of an ST depression partition of 130 microV (p less than 0.001). However, test performance of the ST integral was greatly improved by simple heart rate adjustment: at a matched specificity of 96%, an ST-HR integral partition of 0.154 microV-s/beat per min identified coronary disease in the 100 patients with a sensitivity of 90%, a value significantly greater than the 59% sensitivity of standard criteria and 65% sensitivity of ST depression criteria (each p less than 0.001) and similar to the 91% sensitivity of the ST-HR index and 93% sensitivity of the ST-HR slope (each p = NS). Comparison of receiver-operating characteristic curves confirmed the superior overall test performance of the ST-HR integral relative to the ST integral and ST segment depression, and demonstrated improved performance that was comparable with that of the ST-HR index and the ST-HR slope.(ABSTRACT TRUNCATED AT 250 WORDS)     

平板运动试验时的QT离散度诊断冠心病的价值

为了解ＱＴ离散度（ＱＴｄ）在运动试验中的变化对冠心病心肌缺血的诊断价值，对３０例临床诊断或疑诊为冠心病的病人先后行平板运动试验（简称运动试验）及冠状动脉（简称冠脉）造影检查。１７例运动试验阳性者中１０例确诊为冠心病；１３例运动试验阴性者中１０例冠状动脉正常。运动试验诊断冠心病的敏感性７６．９％、特异性５８．８％、准确性６６．７％。冠心病组与冠脉正常组运动前、中、后ＱＴｄ分别为４６．２５±２０．１３ｍｓ、７１．９２±２０．３７ｍｓ、５１．２５±１４．４８ｍｓ及３２．３５±６．６４ｍｓ、３０．８８±９．２３ｍｓ、２９．３８±８．５４ｍｓ，两者比较，Ｐ均＜０．０１。冠心病组运动前、后与运动中ＱＴｄ比较，差异有显著性，Ｐ＜０．００５；而冠脉正常组ＱＴｄ变化无显著性。以运动中ＱＴｄ≥６０ｍｓ为异常，诊断冠心病的敏感性为９２．３％、特异性１００％、准确性９６．７％。提示运动试验中ＱＴｄ增加可作为诊断冠心病心肌缺血的敏感而特异的指标     

Prognostic value of heart rate adjustment of exercise-induced ST segment depression in the multiple risk factor intervention trial

Objectives.We sought to assess the effect of heart rate adjustment of ST segment depression on risk stratification for the prediction of death from coronary artery disease.Background.Standard analysis of the ST segment response to exercise based on a fixed magnitude of horizontal or downsloping ST segment depression has demonstrated only limited diagnostic sensitivity for the detection of coronary artery disease and has variable test performance in predicting coronary artery disease mortality. Heart rate adjustment of the magnitude of ST segment depression has been proposed as an alternative approach to increase the diagnostic and prognostic accuracy of the exercise electrocardiogram (ECG).Methods.Exercise ECGs were performed in 5,940 men from the Usual Care Group of the Multiple Risk Factor Intervention Trial at entry into the study. An abnormal ST segment response to exercise was defined according to standard criteria as ≥ 100 μV of additional horizontal or downsloping ST segment depression at peak exercise. The ST segment/heart rate index was calculated by dividing the change in ST segment depression from rest to peak exercise by the exercise-induced change in heart rate. An abnormal ST segment/heart rate index was defined as >1.60 μV/beats per min.Results.After a mean follow-up of 7 years there were 109 coronary artery disease deaths. Using a Cox proportional hazards model, a positive exercise ECG by standard criteria was not predictive of coronary mortality (age-adjusted relative risk [RR] 1.5,95% condence interval [CI] 0.6 to 3.6, p = 0.39). In contrast, an abnormal ST segment/heart rate index significantly increased the risk of death from coronary artery disease (age-adjusted RR 4.1, 95% CI 2.7 to 6.0, p < 0.0001). Excess risk of death was confined to the highest quintile of ST segment/heart rate index values, and within this quintile, risk was directly related to the magnitude of test abnormality. After multivariate adjustment for age, diastolic blood pressure, serum cholesterol and cigarettes smoked per day, the ST segment/heart rate index remained a significant independent predictor of coronary death (RR 3.6, 95% CI 2.4 to 5.4, p < 0.001).Conclusions.Simple heart rate adjustment of the magnitude of ST segment depression improves the prediction of death from coronary artery disease in relatively high risk, asymptomatic men. These findings strongly support the use of heart rate-adjusted indexes of ST segment depression to improve the predictive value of the exercise ECG.     

Changes in QT dispersion during adenosine infusion

BACKGROUND: QT dispersion (QTd) measurement during treadmill stress testing has been to shown to improve the accuracy of exercise electrocardiogram (ECG) in the detection of significant coronary artery disease (CAD). HYPOTHESIS: The aim of this study was to determine whether adenosine-induced changes in QTd could predict significant CAD and to assess its efficacy as a diagnostic index in patients undergoing adenosine stress test. METHODS: QT interval measurements were made in 57 consecutive patients undergoing adenosine sestamibi stress test. Patients with an abnormal stress test underwent coronary angiography. Patients with significant disease by coronary angiography (> 70% stenosis) were classified as having CAD (Group 1), and those with normal stress images and/or normal coronaries by angiography were classified as having no CAD (Group 2). RESULTS: QT dispersion increased from 28.2 +/- 4.5 to 43.8 +/- 4.5 ms with a delta QTd of 15.53 +/- 3.68 in Group 1 (p = 0.001) and from 28.4 +/- 2.6 to 34.8 +/- 2.8 ms with a delta QTd of 6.58 +/- 2.21 ms in Group 2 (p = 0.006). Patients in Group 1 had a significantly higher increase in QTd (delta QTd) than the patients in Group 2 (p < 0.03). Addition of delta QTd (> 10 ms) to the ST depression during adenosine infusion would increase the sensitivity of the ECG from 23 to 65% and decrease the specificity from 91 to 70% for diagnosis of significant CAD. CONCLUSIONS: delta QTd is significantly more prolonged in patients with CAD during adenosine infusion. It increases the sensitivity of the stress ECG in diagnosis of CAD during adenosine infusion when used as an adjuvant index.