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     

食道心房超速负荷试验中QT间期离散度诊断冠心病的价值

目的 :评价食道心房超速负荷试验的 QT间期离散度 （QTd）诊断冠心病的价值。方法 :对 32例冠心病患者 （冠心病组 ）及 34例正常者 （对照组 ）进行食道心房超速负荷试验 ,记录试验前后 12导联同步心电图 ,测量其 ST段、校正 QT间期 （QTc）及 QTd。根据 ROC曲线求出 QTc及 QTd的截断点 ,以冠脉造影为诊断冠心病的标准诊断方法 ,利用四格表法 ,分别计算各观测指标的特异度及敏感度。并与“并联试验”相互比较。结果 :ST段下移、QTc,QTd诊断冠心病的特异度分别为 10 0 % ,6 8% ,94% ;敏感度分别为 5 3% ,78%和 84%。 ST段下移和 QTd并联试验时敏感度可达 94%。结论 :食道心房超速负荷试验时 ,如以传统的诊断指标 ST段下移 ,结合 QTd,可明显提高其诊断的敏感度 ,可作一项重要参考指标     

T离散度诊断冠心病心肌缺血的价值

为探讨QT离散度 (QTd)诊断冠心病心肌缺血的价值 ,记录 5 1例冠心病胸痛发作时 ,发作前、后的 12导联同步体表ECG ,测定并计算QTd、校正的QTd(QTcd)及ST段变化 ,判断有关指标诊断冠心病心肌缺血的灵敏性和特异性。结果 :心绞痛 (AP)发作时QTd及ST段改变显著高于胸痛发作前、后的QTd及ST改变 (分别为 80 .1± 2 2 .4vs4 5 .8± 16 .2 ,4 7.8± 17.0 0ms ,P <0 .0 5 ;0 .12± 0 .0 0 8vs 0 .0 3± 0 .0 0 9,0 .0 2± 0 .0 0 7mV)。QTd增大至≥ 80ms、QTd增加≥ 5 0 %、QTd增加≥ 5 0 %兼≥ 80ms、ST段压低或抬高≥ 0 .1mV诊断心肌缺血的灵敏性分别为 86 .2 7%、80 .39%、78.4 3%、5 2 .94 % ;特异性分别为 90 .70 %、79.0 7%、10 0 %、88.37%。结论 :AP发作时QTd显著增大 ,QTd的有关定量指标可作为诊断冠心病心肌缺血的良好指标 ,其中以QTd增加≥ 5 0 %兼≥ 80ms特异性最好。     

踏车运动试验中校正QT间期的应用价值

目的 :探讨校正 QT间期 (Q Tc)在踏车运动试验中的变化及意义。方法 :分析 16 5例确诊或疑诊冠心病 (CHD)而行冠状动脉造影检查的患者亚极量踏车运动试验前后 QTc的动态变化 ,计算以运动后即刻 QTc≥430 ms作为运动试验阳性判断标准的临床价值 ,并与传统 ST段下移标准的临床价值进行对照。结果 :CHD组运动后即刻 ,2、4m in QTc较运动前均显著延长 (均 P <0 .0 1) ,而冠状动脉正常组运动后即刻 QTc较运动前仅轻度延长 (P <0 .0 5 ) ;以运动后即刻 QTc≥ 430 ms作为运动试验阳性的判断标准 ,其特异性、敏感性、准确性、阳性预测值、阴性预测值分别为 0 .886 (P <0 .0 2 )、0 .884(P >0 .0 5 )、0 .885 (P <0 .0 2 )、0 .913(P <0 .0 5 )、0 .849(P>0 .0 5 ) ,显著优于传统的 ST段下移标准。结论 :运动后即刻 QTc≥ 430 ms可作为运动试验阳性的判断标准 ,它有利于克服 ST段下移标准误诊率高、假阳性率高的缺点     

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.     

复合试验后△QTc改变对冠心病诊断的估价

本文采用潘生丁—食管心房调搏心脏负荷复合试验观察35例冠心病和31例健康人试验前、后QTc和ΔQTc变化,结果提示:冠心病组ΔQTc与健康组比较有显著性差异(0.036±0.014秒,0.013±0.014秒,P<0.01)。如取QTc≥0.425秒和ΔQTc≥0.03秒为阳性标准,其敏感性为78％,75％,特异性为93.6％,90.6％。并注意到随着刺激频率增加,冠心病组ΔQTc有逐渐延长趋势。我们建议在复合试验的基础上参考ΔQTc和QTc的变化,可进一步提高潘生丁试验的特异性。     

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。     

QTcd／HR斜率评价食管心房调搏负荷试验对冠心病的诊断价值

目的 研究经食管心房调搏负荷试验（TEAPT）中,心率调整QTd指标对冠心病的诊断价值。方法 50例研究对象在作冠状动脉造影术前后一周内进行TEAPT,记录试验前、每级起搏末的常规12导联心电图。测定每一时点心电图的QTd、QTcd值,计算QTcd／HR斜率（SQTcd）,并比较各项指标间及与ST段压低标准间的诊断效能。结果 冠心病（CAD）组（n=27）的负荷峰值QTd(QTdp)、峰值QTcd(QTcdp)、SQTcd值均显著大于冠脉无显著狭窄（NCAD,n=23)组（t≥5.18,P＜0．001）,此3个QT d有关参数在NCAD组的95％上限值分别为60ms、95ms、0．74ms/bpm。以它们为界限值,此3个参数诊断冠心病的特异性均显著大于ST压低标准（P＜0．05）,SQTcd的敏感性和准确性显著高于QTcdp及ST压低标准（P＜0．05－0．01）。结论 TEAPT可行、安全、无创,SQTcd是TEAPT诊断CAD的准确新指标。     

平板运动试验中IQTd诊断冠心病的价值

目的　评价用心率调整QTd指标 (IQTd)在平板运动试验中对冠心病的诊断价值。方法　 4 3例患者在冠状动脉造影前行平板运动试验 (ETT) ,测量其运动前、运动中与ST段下移最大时或最大负荷心率时 (无ST段下移者 )QTd、校正QTd(QTdr、QTcdr、QTdp、QTcdp) ,分别计算IQTd和IQTcd。ETT后 1周内行冠状动脉造影 (CAG) ,根据CAG结果分为冠心病 (CAD)组 2 3例和冠状动脉正常 (NCAD)组 2 0例。结果　运动前的QTdr和QTc dr在CAD与NCAD组间无显著差别。在冠状动脉正常组 ,运动过程QTdp和QTcdp无显著增加 ,而在冠心病组QTdp和QTcdp有显著性增加 (P <0 0 0 1)。在运动过程中 ,QTdp、QTcdp、IQTd、IQTcd在CAD与NCAD组间有明显差异。在NCAD组QTdp、QTcdp、IQTd、IQTcd95 %上限值分别为 74ms、86ms、0 .17ms/bpm和0 2ms/bpm。用其界值作为诊断标准 ,其特异性显著高于ST段压低 ,IQTd和IQTcd的敏感性和准确性显著高于ST压低 (P <0 0 5 )。结论　提示IQTd、IQTcd可作为平板运动试验中诊断冠心病敏感、准确和特异的指标     

女性踏车运动试验中QTc延长的意义

目的 :探讨女性踏车运动试验前后校正QT间期的变化及意义。方法 :分析 14 5例行冠状动脉 (冠脉 )造影检查的女性患者亚极量踏车运动试验前后QTc的动态变化 ,计算以运动后即刻QTc较运动前QTc延长≥ 4 0ms作为运动试验阳性判断标准的临床价值 ,并与传统ST下移标准的临床价值进行对照。结果 :冠心病(CHD)组运动后即刻QTc与运动前QTc的差值 (即刻ΔQTc)较非CHD组显著增大 ,且随冠脉狭窄程度的加重而增大 ;以运动后即刻ΔQTc≥ 4 0ms作为运动试验阳性的判断标准 ,其特异性、敏感性、准确性分别为 90 .0 % (P<0 .0 5 )、88.7% (P <0 .0 1)、89.0 % (P <0 .0 1) ,显著优于传统的ST标准。结论 :女性CHD患者运动试验后QTc显著延长 ,运动后即刻ΔQTc≥ 4 0ms可作为女性运动试验阳性的判断标准 ,它有利于克服运动试验中ST标准对女性CHD患者误诊率高、假阳性率高的缺点     

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     

运动试验时QT间期离散度诊断冠心病的价值

目的探讨QT离散度（QTd）在运动试验中的变化,及其对冠心病心肌缺血的诊断价值。方法 68例临床诊断或疑诊为冠心病的患者先后行平板运动试验（简称运动试验）及冠状动脉造影（简称冠脉造影）检查。结果 47例运动试验阳性者中30例确诊为冠心病;21例运动试验阴性者中19例冠状动脉正常。冠心病组与冠脉正常组运动前、中、后QTd分别为42.38±19.28 ms、70.58±19.45 ms、50.14±13.56 ms及31.18±6.25 ms、30.01±9.05 ms、28.24±8.12 ms,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≥60 ms为异常,诊断冠心病的敏感性为90.9%、特异性100%、准确性94.9%。结论提示运动试验中QTd增加可作为诊断冠心病心肌缺血的敏感而特异的指标。     

Effect of ST segment measurement point on performance of standard and heart rate-adjusted ST segment criteria for the identification of coronary artery disease

BACKGROUND. Recent reports critical of the performance of heart rate-adjusted indexes of ST depression during exercise electrocardiography have used J-point rather than ST segment measurements. However, no standard exists for the optimal time after the J-point at which to measure ST segment deviation. METHODS AND RESULTS. To assess the effect of ST segment measurement position on performance of standard exercise electrocardiographic criteria, the delta ST segment/heart rate (delta ST/HR) index, and the ST segment/heart rate (ST/HR) slope for the detection of coronary artery disease, the exercise electrocardiograms of 50 clinically normal subjects and 80 patients with known or likely coronary disease were analyzed using ST depression measured at both the J-point and at 60 msec after the J-point (J + 60). A positive exercise electrocardiogram by standard criteria, defined as 0.1 mV or more of additional horizontal or downsloping ST depression at end exercise, had a specificity of 96% when ST depression was measured at either the J-point or J + 60. There was no difference in sensitivity of standard electrocardiographic criteria at J + 60 and J point (both 59%, p = NS). However, at matched specificity of 96%, the delta ST/HR index and ST/HR slope calculated using ST depression at J + 60 were significantly more sensitive (90% and 93%) than when calculated using J-point depression (64% and 61%, each p less than 0.001). Comparison of areas under respective receiver operating characteristic curves confirmed the superior performance of J + 60 as opposed to J-point measurements for both the delta ST/HR index (0.98 versus 0.89, p = 0.006) and the ST/HR slope (0.96 versus 0.87, p = 0.007) and also demonstrated modestly improved overall test performance for standard electrocardiographic criteria using J + 60 measurements (0.88 versus 0.82, p = 0.001). CONCLUSIONS. Use of J-point measurements significantly degrades performance of heart rate-adjusted indexes of ST depression but has less effect on standard criteria.     

Comparison of ST segment/heart rate index to standard ST criteria for analysis of exercise electrocardiogram

The objective of our study was to compare the discriminating power of a proposed ST segment/heart rate index with that of a standard method of assessing exercise-induced ST segment depression for diagnosing coronary artery disease. We used a cross-sectional retrospective analysis of exercise test and coronary angiographic data. The study took place in a 1,200-bed Veterans Affairs Medical Center; participants were 328 male patients who had undergone both a sign and symptom-limited treadmill test and coronary angiography. The sensitivity of the ST segment/heart rate index was 54% at a cut point of 0.021 mm/(beats/min), corresponding to a specificity of 73%. The standard visual ST segment analysis had a sensitivity of 58% at this same specificity, which corresponded to an ST segment cut point of 1-mm depression relative to rest (p = NS). Similarly, for diagnosing three-vessel or left main coronary disease, no significant difference was found between the sensitivities or the two measurements at cut points of equivalent specificity. In this consecutive series of patients presenting for routine clinical testing, the ST segment/heart rate index did not improve the diagnostic accuracy of the exercise test for identifying the presence or severity of coronary artery disease relative to standard visual criteria.