Sporton S C, Taggart P, Sutton P M, Walker J M, Hardman S M
Department of Academic, University College London Medical School, UK.
Lancet. 1997 Feb 1;349(9048):306-9. doi: 10.1016/S0140-6736(96)06143-0.
The aim of this study was to test the hypothesis that acute myocardial ischaemia increases QT dispersion measured from the 12-lead electrocardiogram.
Incremental atrial pacing was used to induce myocardial ischaemia in 18 patients with coronary artery disease and QT dispersion was measured. Six patients with normal coronary arteries served as the control group.
All the patients with coronary artery disease developed angina and/or ST depression accompanied by marked increases in QT dispersion (mean increase 38 ms, 95% CI 30 to 45 ms, p < 0.001). In contrast, in the six patients with normal coronary arteries who remained without symptoms and without ST changes, there was no significant change in QT dispersion in response to pacing. Baseline QT dispersion did not distinguish those patients with coronary artery disease from those with normal coronary arteries (44 ms [95% Cl 39-49 ms] vs 40 ms [25-55 ms]), respectively.
These results demonstrate that myocardial ischaemia induced by incremental atrial pacing in patients with coronary artery disease causes an acute increase in QT dispersion. Such "inducible" QT dispersion may prove more useful than resting QT dispersion in assessing the individual risk of arrhythmic events in patients with coronary artery disease.
本研究的目的是检验急性心肌缺血会增加从12导联心电图测得的QT离散度这一假设。
采用递增性心房起搏诱导18例冠心病患者发生心肌缺血，并测量QT离散度。6例冠状动脉正常的患者作为对照组。
所有冠心病患者均出现心绞痛和/或ST段压低，同时QT离散度显著增加（平均增加38毫秒，95%可信区间30至45毫秒，p<0.001）。相比之下，6例冠状动脉正常且无症状及ST段改变的患者，起搏后QT离散度无显著变化。基线QT离散度无法区分冠心病患者和冠状动脉正常的患者（分别为44毫秒[95%可信区间39 - 49毫秒]和40毫秒[25 - 55毫秒]）。
这些结果表明，递增性心房起搏诱导冠心病患者发生心肌缺血会导致QT离散度急性增加。在评估冠心病患者心律失常事件的个体风险时，这种“可诱导的”QT离散度可能比静息QT离散度更有用。
