不同程度冠心病患者QT变异和QT变异指数的观察

QT interval variability and QT variability index among coronary heart disease.

目的探讨冠心病患者的QT变异(QTV)和病变程度的相关性。方法122例冠心病患者(75例劳累性心绞痛患者,47例非ST段抬高性心肌梗死患者)和55例正常对照组,在保持日常生活起居的情况下佩戴12导联动态心电图监测仪,计算机辅助下自动测量QT间期,计算相应时间段的QT间期均值(QTm)、QTV、HR间期均值(HRm)、HR间期变异(HRV)和QT变异指数(QTVI)。同时采用时域法(SDNN)和频域法(LF、HF)分析心率变异性。结果①正常对照组24hLF/HF、HF、QTV均呈昼夜节律性变化。②非ST段抬高性心肌梗死组、劳累性心绞痛组和正常对照组之间的QTV差异显著(29.2±13.6ms、26.8±13.1ms、21.7±12.4ms,P<0.05)。③正常对照组QTV与SDNN存在负相关,相关系数为-0.40,P<0.05。而劳累性心绞痛组和非ST段抬高性心肌梗死组的QTV与SDNN无相关性,P>0.05。④QTV、QTVI随着冠状动脉病变程度的加重而变大,且各组比较有显著性差异,P<0.05。结论QTV与冠状动脉病变程度有关,QTV的变化不仅依赖于自主神经,而且是许多不同病理生理因素作用的结果,在心肌缺血的情况下,能更直接地反映心肌的代谢和病变状态。

Objective To investigate the relationship between QT interval variability （QTV） and the severity of coronary heart disease. Methods 75 effort angina pectoris patients, 47 non-ST-segment elevation myocardial infarction patient and 55 healthy subjects underwent 24 hours Holter monitoring in normal life style. The mean QT intervals （ QTm）, the standard deviation of QT intervals （ QTV）, the mean HR intervals （ HRm）, the standard deviation of HR intervals （ HRV）, and QT variability index（QTVI） were calculated for every hour during the day and the night. The heart rate variability （SDNN and LF/HF, HF） were analyzed simultaneously by computer for every hour during 24 hours. Results ① The QTV was larger during the day than during the night in healthy subjects. ②The patients of non-ST-segment elevation myocardial infarction and effort angina pectoris displayed significantly higher values of QTV compared with the healthy subjects （29.2 ± 13.6 ms.26.8 ± 13.1 ms.21.7 ± 12.4 ms,P 〈0.05）. ③The QTV had a negative correlation with SDNN in healthy subjects, but not in coronary patients. ④The QTV and QTVI significantly correlated with the severity of coronary artery disease in the effort angina pectoris. Conclusions QTV and QTVI are related not only to the autonomic nervous activity, but also to the metabolizability and pathological changes of ventricular myocardium.