【摘要】 目的 探讨QT离散度(QTd)的正常参考值及在不同心电图记录纸速、不同时间重复测量、不同测量方法之间的可重复性。方法 分别以纸速25mm/s、50mm/s记录504例健康成人体表12导联同步心电图，用手工分规和电脑半自动测量QTd，比较不同心电图纸速、不同时间重复测量、不同测量方法之间的可重复性。结果 (1)同一或不同测量者不同时间内重复测量的QTd、QTcd、RR间期显著相关，r分别为0.93、0.95、0.99，P均小于0.01。(2)计算机半自动测量与手工分规测量的QT、QTd显著相关，r分别为0.84、0.88，P均小于0.01。(3)在25mm/s纸速与50mm/s纸速的心电图分别测量QTd、QTcd、RR间期，两次结果相关性好，r分别为0.86、0.84、0.96，P均<0.05。(4)用不同方法测量QTd、QTcd的结果差异无显著性，其平均误差小于7ms。(5)QTd、QTcd的正常参考值为45±13ms、49±14ms。结论 ①QTd在不同心电图记录纸速、不同时间重复测量、不同测量方法之间显著相关，可重复性好。②QTd的正常参考值为45±13ms，范围为20～70ms。

    The study of methodology and normal value of QT dispersion(QTd) Liu Yan, Guo Yingchun, Ma Yi, et al.Department of Cardiology, First Affiliated Hospital, Xi ′an Medical University,Xi ′an710061

     【Abstract 】 Objective This study wasaimed to investigate the normal value and reproducibility of QTd in different paperspeeds, different times of measurements repeated by same or different observers, and tocompare user-interactive computer (mouse and computer screen) with manual dividersmeasurements.Methods The 12-lead synchronyelectrocardiograms (ECGs) in 504 healthy people (age:18-60 years) were recorded at 25mm*s^-1 and 50mm*s^-1 paper speeds. All ECGs at 50mm*s^-1 were analysed fornormal value of QTd by manual dividers. 60 of 504 ECGs chosen randomly were re-analysed atleast 1 month after the first measurment by both manual and computer methods. The ECGs at25mm*s^-1 of these 60 people were measured by manual dividers only.Results (1) The QTd, QTcd showed a significant correlation between thedifferent paper speeds (25mm*s^-1 and 50mm*s^-1 ), differentmeasurements repeated by same or different observers, and different methods, the r valueswere from 0.84 to 0.99, P<0.05. The repeat measurement errors of QTd was 6ms,user-interactive computer and manual dividers measurement errors were 6ms, 25mm*s^-1 and 50mm*s^-1 ECGs errors of QTd was 7ms. (2)The QTd 、QTcd 、QRSd of these healthyadults were 45±13 (20-70),49±14 (25-75), 29±11 (10-65)ms respectively.Conclusion There are good correlations and reproducibility of QTd in differentpaper speeds, repea-ting measurements by same or different observers, and the differentways in measurement.

     【Key words 】 QT dispersion electrocardiography reference values

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