Shimizu W, Kamakura S, Ohe T, Kurita T, Takaki H, Aihara N, Shimomura K
Department of Internal Medicine, National Cardiovascular Center, Oskaka, Japan.
Am J Cardiol. 1994 Oct 15;74(8):780-5. doi: 10.1016/0002-9149(94)90434-0.
The QT interval of the resting 12-lead electrocardiogram is normal or borderline in some patients with congenital long QT syndrome (LQTS). Recently, several in vivo experimental studies have shown that the time of maximum dV/dt in the ST-T segment is correlated with the time of local ventricular recovery. The purpose of this study was to examine the value of the body surface recovery time measured by 87-lead body surface mapping for detecting LQTS. Body surface mapping and 12-lead electrocardiography were performed simultaneously in 18 patients with LQTS and 40 controls of similar age and sex. The recovery time (RT), that is, the interval between QRS onset and the time of maximum dV/dt in the ST-T segment, was measured automatically by computer from each of the 87 mapping leads, and the corrected RT (RTc) was calculated by Bazett's method. The QT interval was measured from each of the 12 standard electrocardiographic leads, and the corrected QT (QTc) interval was also calculated. The maximum RT and RTc, the minimum RT and RTc, and the RT and RTc dispersions (difference between maximum and minimum RT and RTc in each patient) were significantly longer in the LQTS group than in the control group. In addition, a maximum RT of 390 msec, a maximum RTc of 430 msec 1/2, an RT dispersion of 170 msec, and an RTc dispersion of 170 msec1/2 separated the 2 groups completely (i.e., no overlap). The maximum QT and QTc, the minimum QT and QTc, and the QT and QTc dispersions (difference between maximum and minimum QT and QTc in each patient) were also significantly longer in the LQTS group than in the control group. However, the maximum QTc was normal (< or = 440 msec1/2) or borderline (< or = 460 msec1/2) in 5 of the 18 LQTS patients, and none of these parameters clearly separated the 2 groups. These results suggest that measurement of RT by 87-lead body surface mapping is useful for diagnosing latent or borderline LQTS.
在一些先天性长QT综合征（LQTS）患者中，静息12导联心电图的QT间期正常或处于临界值。最近，几项体内实验研究表明，ST-T段最大dV/dt时间与局部心室恢复时间相关。本研究的目的是探讨87导联体表标测测量体表恢复时间对检测LQTS的价值。对18例LQTS患者和40例年龄、性别相似的对照者同时进行体表标测和12导联心电图检查。恢复时间（RT），即QRS波起始至ST-T段最大dV/dt时间的间期，由计算机从87个标测导联中自动测量，并采用Bazett法计算校正恢复时间（RTc）。从12个标准心电图导联中测量QT间期，并计算校正QT（QTc）间期。LQTS组的最大RT和RTc、最小RT和RTc以及RT和RTc离散度（每位患者最大与最小RT和RTc之间的差值）均显著长于对照组。此外，最大RT为390毫秒、最大RTc为430毫秒1/2、RT离散度为170毫秒以及RTc离散度为170毫秒1/2可完全区分两组（即无重叠）。LQTS组的最大QT和QTc、最小QT和QTc以及QT和QTc离散度（每位患者最大与最小QT和QTc之间的差值）也显著长于对照组。然而，18例LQTS患者中有5例的最大QTc正常（≤440毫秒1/2）或处于临界值（≤460毫秒1/2），且这些参数均未清晰区分两组。这些结果表明，87导联体表标测测量RT有助于诊断隐匿性或临界性LQTS。
