Yu G L, Cheng I R, Zhao S P, Zhuang H P, Cai X Y
Department of Geriatric Cardiology, Xiang Ya Hospital, Hunan Medical University, Changsha, PR China.
Int J Cardiol. 1998 Aug;65(3):255-60. doi: 10.1016/s0167-5273(98)00120-x.
To evaluate the clinical significance of QT dispersion after exercise in patients with previous myocardial infarction, QT dispersion (QTd) and corrected QTd (QTcd) were assessed with standard 12 leads electrocardiogram in 90 patients with previous myocardial infarction and 30 healthy persons before and 3 min after a treadmill exercise test. In addition, 24 h ambulatory electrocardiogram and echo-cardiography were examined in all the subjects studied. Patients were followed up for 37.25 +/- 10.71 months. The results showed that there were no significant differences in the QTd and QTcd between the patients and the controls before exercise (36.11 +/- 13.42 ms versus 34.81 +/- 12.32 ms, P>0.05, 41.22 +/- 13.49 as versus 39.91 +/- 13.56 ms, P>0.05). Compared with those before exercise, QTd and QTcd were significantly increased in the patients 3 min after the exercise test (36.11 +/- 13.42 ms versus 47.20 +/- 14.41 ms, P<0.01, 41.22 +/- 13.49 ms versus 59.57 +/- 18.90 ms, P<0.01), but not in the controls (34.81 +/- 12.32 ms versus 38.76 +/- 12.09 ms, P>0.05, 39.91 +/- 13.56 ms versus 43.27 +/- 17.77 ms, P>0.05). The incidences of abnormal contraction of the left ventricular wall, aneurysms, NYHA III class, >III class of Lown's ventricular arrhythmia classification and cardiac sudden death were significantly higher in group A with QTcd >50 ms than that of group B with QTcd <50 ms (P<0.01). These findings indicate that the increased QT dispersion after exercise in 12 standard leads electrocardiogram might be associated with high incidences of sudden cardiac death and ventricular arrhythmia in the patients with previous myocardial infarction.
为评估陈旧性心肌梗死患者运动后QT离散度的临床意义，采用标准12导联心电图对90例陈旧性心肌梗死患者和30例健康人在平板运动试验前及运动后3分钟进行QT离散度（QTd）及校正QT离散度（QTcd）评估。此外，对所有研究对象均进行24小时动态心电图及超声心动图检查。患者随访37.25±10.71个月。结果显示，运动前患者与对照组的QTd及QTcd无显著差异（分别为36.11±13.42毫秒对34.81±12.32毫秒，P>0.05；41.22±13.49毫秒对39.91±13.56毫秒，P>0.05）。与运动前相比，运动试验后3分钟患者的QTd及QTcd显著增加（分别为36.11±13.42毫秒对47.20±14.41毫秒，P<0.01；41.22±13.49毫秒对59.57±18.90毫秒，P<0.01），而对照组无显著变化（分别为34.81±12.32毫秒对38.76±12.09毫秒，P>0.05；39.91±13.56毫秒对43.27±17.77毫秒，P>0.05）。QTcd>50毫秒的A组左心室壁异常收缩、室壁瘤、NYHAⅢ级、Lown室性心律失常分级>Ⅲ级及心脏性猝死的发生率显著高于QTcd<50毫秒的B组（P<0.01）。这些结果表明，12导联心电图运动后QT离散度增加可能与陈旧性心肌梗死患者心脏性猝死及室性心律失常的高发生率相关。
