平板运动试验时的QT离散度诊断冠心病的价值

Diagnostic Value of QT Dispersion for Coronary Artery Disease in Exercise Treadmill Test

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％。

To evaluate the diagnostic value of QT dispersion (QTd) for coronary artery disease (CAD) in exercise treadmill test (ETT),30 patients (mean age 51.7 years, 20 males) suspected CAD were underwent ETT and coronary angiography sequentially.The QTd in 12lead surface ECG before,during and post exercise was measured in every patients.CAD was established in 10 of 17 patients with positive exercise test.10 of 13 patients with negative ETT had normal coronary artery. The sensitivity,specificity and accuracy of ETT by ST segment depression for diagnosis of CAD was 76.9%,58.8% and 66.7%, respectively. QTd was significantly increased in patients with CAD before, during and post exercise (46.25±2013,71.92±20.37 and 51.25±14.48 ms, respectively;before and post vs during,P<0.005) compared to patients with normal coronary artery (32.35±6.64,30.88±9.32 and 29.38±8.54 ms,respectively,P=NS), P<0.01 in all. The stress QTd of ≥60 ms had a sensitivity of 92.3%, specificity of 100% and accuracy of 96.7% for diagnosis of CAD in ETT.Stress QTd increasing is an independent predictor of myocardial ischemia with high sensitivity and specificity in ETT.