Rautaharju P M, Zhou S H, Wong S, Calhoun H P, Berenson G S, Prineas R, Davignon A
Cardiac Epidemiology Coordinating and Research Centre, (EPICORE), Univesity of Alberta, Edmonton.
Can J Cardiol. 1992 Sep;8(7):690-5.
To investigate sex differences in the evolution of the QT interval with age.
A community-based representative North American population sample of 14,379 children and adults aged from birth to 75 years. The measured QT intervals (QTm) were determined by a computer algorithm and QTm, corrected for heart rate (HR), was expressed as QT index: QTI = (QTm/Tp) x 100, where QTp is the predicted QT from the formula QTp (ms) = 656/(1 + HR/100).
The QTI values of females were significantly longer than of males in all age groups from 15 to 50 years tested at yearly intervals. This difference was due to a 20 ms drop in rate-corrected QT values in adolescent males after puberty, whereas QT values of females remained unchanged throughout the growth, maturation and reproductive years. The new QT prediction formula explained 83% of total QT variance in females and 82% in males after adjustment for heart rate and for the observed significant influence of ventricular excitation time (QRS duration) on QT interval in both sexes and a correction for QT age trend in males.
The sex difference in the QT interval is due to QT shortening in males after puberty rather than QT prolongation in women during reproductive years. The fact that QRS duration is a significant determinant of the QT interval has important theoretical implications for attempts to model the ventricular repolarization process and it indicates that the traditional concept of reverse sequence of ventricular repolarization is not universally valid in all myocardial regions.
研究QT间期随年龄变化的性别差异。
以社区为基础，选取了14379名年龄从出生到75岁的北美人群作为具有代表性的样本。通过计算机算法测定QT间期（QTm），并将校正心率（HR）后的QTm表示为QT指数：QTI = (QTm/Tp) x 100，其中QTp是根据公式QTp（毫秒）= 656/(1 + HR/100)预测的QT。
在对15至50岁的所有年龄组进行逐年测试时，女性的QTI值显著长于男性。这种差异是由于青春期后青少年男性经心率校正的QT值下降了20毫秒，而女性的QT值在整个生长、成熟和生殖期保持不变。在调整心率、考虑到心室激动时间（QRS时限）对男女QT间期的显著影响以及对男性QT年龄趋势进行校正后，新的QT预测公式解释了女性总QT变异的83%和男性的82%。
QT间期的性别差异是由于男性青春期后QT缩短，而非女性在生殖期QT延长。QRS时限是QT间期的重要决定因素这一事实，对于模拟心室复极过程的尝试具有重要的理论意义，并且表明传统的心室复极逆向顺序概念并非在所有心肌区域都普遍有效。
