P-R段明显下斜对运动试验假阳性的预测作用

Value of markedly downsloping PR segments for predicting false positive exercise tests

目的探讨下壁导联P-R段明显下斜与运动试验假阳性的关系。方法比较76例运动试验阳性经冠状动脉造影确诊为真阳性组57例、假阳性组19例的运动试验参数。结果假阳性组有较长的运动总时间(389±112s∶287±95s,P<0.01),达到较大的代谢当量(7.9±1.9mets∶6.6±1.5mets,P<0.01),ST段压低≥1mm时间延长(284±140s:192±97s,P<0.01),运动中较少诱发胸痛及至少2个下壁导联P-R段明显下斜的比例较高(74%∶20%,P<0.01),若以运动总时间≥300s、至少2个下壁导联P-R段明显下斜判断运动试验假阳性,其敏感性为63%,特异性为91%,预测价值为88%。结论运动总时间≥300s、至少2个下壁导联P-R段明显下斜对运动试验假阳性的判断有较高的特异性。

Objective We assessed value of markedly downsloping PR segments in inferior leads for predicting false positive exercise test. Methods Seventy-six patients with a positive test were classified according to coronary angiography into two groups,true positive (n=57)and false positive(n=19). We compared two groups' parameters of exercise tests. Results Patients with false positive exercise tests had exercise duration 5 minutes or longer, markedly downsloping PR segments in two or more of inferior leads Ⅱ,Ⅲand aVF,less frequent chest pain and later occurrence≥1mm ST depression during exercise test. Sensitivity,specificity and predictive value of PRsegment and exercise duration criterion for predicting a false positive exercise test were 63%,91%and 88%,respectively. Conclusion We found markedly downsloping PR segments in at least two of three inferior ECG leads,along with exercise duration ≥300s could predict false positive exercise tests with relatively high specificity.