心脏变时指数对冠心病的诊断

Value of chronotropic index in identifying coronary artery disease.

目的评价心脏变时指数对冠心病的诊断价值。方法对疑诊冠心病的162例患者，先常规行运动平板试验，测定运动试验过程中心电图ST段变化值和心脏变时指数。平板运动试验后3周内行冠状动脉造影检查，以冠状动脉造影结果作为诊断冠心病的标准。结果心脏变时指数标准与传统ST段标准诊断冠心病的敏感性为70．1％和60．9％（P〈0．05），特异性为84．0％和73．3％（P〈0．05），准确性为76．5％和66．7％（P〈0．05）。心脏变时指数指标与冠状动脉造影一致性检验的Kappa值为0．534（〉0．4）。心脏变时指数与冠状动脉病变支数相关，心脏变时指数平均值从0支冠状动脉病变的0．88±0．09，逐渐下降到3支冠状动脉病变的0．68±0．06（P〈0．01）。相关性分析显示心脏变时指数阳性与右冠状动脉病变的相关性更好。结论心脏变时指数可能成为诊断冠心病的一项阳性指标，其敏感性、特异性和准确性均高于ST段标准的普通运动心电图试验。

Objective To assess the diagnostic value of chronotropic index in identifying coronary artery disease （CAD）. Methods One hundred and sixty two patients with suspected CAD were referred for a routine treadmill exercise electrocardiogram and subsequently underwent selective coronary angiography within 3 weeks. The magnitude of ST segment depression and chronotropic index were measured by a computerized ECG system. CAD was defined by coronary angiography. Results In detecting CAD, the sensitivity was 70. 1% versus 60. 9% （ P 〈 0.05 ）, the specificity was 84.0% versus 73.3 % （ P 〈 0.05 ）, and the accuracy was 76.5 % versus 66.7 % （ P 〈 0.05） by chronotropic index and standard electrocardiographic test criteria. The value of Kappa statistic for chronotropic index consistency in our experiment was 0.534（ 〉 0.4）. The number of diseased vessels was correlated with the mean value of chronotropic index. The chronotropic index decreased from 0. 88 ± 0. 09 in patients without coro- nary disease to 0. 68 ±0.06 in those with 3 vessels involved （P 〈0. 01 ）. A more closed relationship was found between chronotropic index and lesion in the right coronary artery. Conclusions Chronotropic index is possibly a valuable positive index for the diagnosis of CAD. The sensitivity, specificity and accuracy of chronotropic index are significantly higher than those of standard electrocardiographic test criteria in identifying CAD.