平板运动负荷试验中冠心病患者QT间期的动态变化

Dynamic alternation of QT interval in the treadmill exercise testing of patients with coronary heart disease.

目的观察冠心病患者平板运动负荷试验中QT间期的动态变化规律并探讨其机制。方法收集经冠状动脉造影确诊的冠心病患者21例和对照组20例，分析两组受试者冠状动脉造影前的平板运动负荷试验心电图，每位受试者测量50个点的RR间期、QTp间期和QTe间期，计算QTpc间期、QTec间期和Tp—Te间期。以RR间期为横坐标，QTp间期、QTe间期、QTpc间期、QTec间期或Tp—Te间期为纵坐标，作直线相关分析，求相关直线斜率。结果平板运动负荷试验伞程，冠心病组QTe／RR斜率高于对照组（P〈0．05），而两组间QTp／RR、QTpc／RR、QTec／RR和Tp—Te／RR斜率比较差异无统计学意义（P〉0．05）；运动期，冠心病组QTe／RR和QTec／RR斜率高于对照组（P〈0．05）；恢复期，冠心病组QTpc／RR斜率高于对照组（P〈0．05），Tp—Te／RR斜率低于对照组（P〈0．05）。冠心病组运动期QTe／RR、QTec／RR和Tp—Te／RR斜率高于恢复期（P〈0．05），运动期QTpc／RR斜率低于恢复期（P〈0．05）。对照组运动期和恢复期QTe／RR、QTp／RR、QTec／RR、QTpc／RR和Tp．Te／RR斜率比较差异均无统计学意义（P〉0．05）。结论冠心病患者运动负荷试验中的QT滞后现象与交感神经张力异常增高和T波终末部的异常动态改变有关。

Objective To investigate the dynamic alternation of QT interval in treadmill exercise testing（TET） of patients with coronary heart disease（CHD） and its underlying mechanisms. Methods Twenty-one patients with CHD,which were diagnosed based on their coronary artery angiography results, were enrolled as CHD group. Twenty people with negative angiography results were enrolled as control group （CON）. All subjects underwent treadmill exercise test according to Bruce protocol. For each recording,50 points were selected for the RR, QTp,and QTe interval measurement. QTpc ,QTec and Tp-Te were calculated. QTp, QTe, QTpc, QTec and Tp-Te interval were plotted against corresponding RR interval using linear regression analysis, respectively. The slopes of correlation line were calculated. Results During whole period of TET, the QTe/RR slope of CHD group was higher than CON group （ P 〈 0.05 ）, but QTp/RR, QTpc/RR, QTec/RR and Tp-Te/RR slope didn＇t show significant difference （P 〉 0.05 ）. During exercise period, the QTe/RR and QTec/RR slope were significant higher in CHD group（ P 〈 0.05 ）. During recovery period, the QTpc/RR slope were significant higher in CHD group （ P 〈 0. 05 ） , and Tp-Te/RR slope were significant lower in CHD group（ P 〈 0.05 ）. In CHD group ,the QTe/RR, QTec/RR and Tp-Te/RR slope of exercise period were significantly higher than recovery period （ P 〈 0.05 ） , the QTpc/RR slope of exercise period were significantly lower than recovery period （ P 〈 0.05 ）. In CON group, all QTe/RR, QTp/RR, QTec/RR, QTpc/RR and Tp-Te/RR slope didn＇ t show significant difference between exercise and recovery period（ P 〉 0.05 ）. Conclusion In treadmill exercise testing, patients with CHD show overt QT interval hysteresis phenomenon, which relates to increased activity of sympathetic nerve and abnormal dynamic alternation in Tp-Te interval.