Zareba W, Moss A J, Konecki J
University of Rochester Medical Center, New York 14642, USA.
J Electrocardiol. 1998;30 Suppl:191-5. doi: 10.1016/s0022-0736(98)80074-5.
The purpose of this study was to evaluate area-derived parameters of repolarization dispersion in LQTS patients and their unaffected family members and to use this analysis to challenge the concept of dispersion of repolarization in surface ECG. The area under the curve between the J point and the next P wave was measured automatically in 12 leads of the digital ECG in 34 LQTS patients and 22 unaffected family members. The area-derived measures of repolarization included total repolarization area, T wave amplitude, time to accumulate the first (tA50) and the median (tA25-75) 50% of the total area, and the time to accumulate 97% of the total repolarization area (tA97). In comparison with unaffected family members, LQTS patients had significantly higher dispersion of tA50 (tA50-SD = 34 +/- 18 ms vs 11 +/- 6 ms, respectively, P < .001) and tA25-75 (t[A25-75]-SD = 44 +/- 19 ms vs 24 +/- 15 ms, respectively, P < .001), whereas no significant difference was observed in the dispersion of total repolarization area, T wave amplitude, and time to accumulate total repolarization area (tA97-SD = 44 +/- 20 ms vs 53 +/- 19 ms, respectively, ns). It is concluded the analysis of area-derived parameters of repolarization showed that LQTS patients have increased interlead variability of the repolarization morphology (tA50-SD and t[A25-75]-SD), whereas they do not have increased dispersion of the total repolarization duration (tA97-SD). This observation indicates that an increase in traditional measures of dispersion (QT dispersion) may represent a heterogeneity of repolarization shape, whereas the true dispersion of the total duration of repolarization, which is related to electrocardiographic lead projection, is similar in patients and healthy subjects.
本研究的目的是评估长QT综合征（LQTS）患者及其未受影响的家庭成员中基于面积的复极离散参数，并利用该分析对体表心电图复极离散的概念提出质疑。在34例LQTS患者和22名未受影响的家庭成员的数字心电图的12导联中自动测量J点与下一个P波之间的曲线下面积。基于面积的复极测量指标包括总复极面积、T波振幅、累积总面积的第一个50%（tA50）和中位数50%（tA25 - 75）的时间，以及累积总复极面积的97%（tA97）的时间。与未受影响的家庭成员相比，LQTS患者的tA50离散度（tA50 - SD分别为34±18 ms和11±6 ms，P <.001）和tA25 - 75离散度（t[A25 - 75] - SD分别为44±19 ms和24±15 ms，P <.001）显著更高，而在总复极面积、T波振幅和累积总复极面积的时间离散度方面未观察到显著差异（tA97 - SD分别为44±20 ms和53±19 ms，无显著性差异）。结论是，对基于面积的复极参数的分析表明，LQTS患者复极形态的导联间变异性增加（tA50 - SD和t[A25 - 75] - SD），而总复极持续时间的离散度并未增加（tA97 - SD）。这一观察结果表明，传统离散度测量指标（QT离散度）的增加可能代表复极形状的异质性，而与心电图导联投影相关的总复极持续时间的真正离散度在患者和健康受试者中相似。
