心肌梗死后期不同时段QT离散度变化的临床意义

The significance of QT dispersion in different phases in patients with healing myocardial infarction

目的 :研究心肌梗死 (MI)后期不同时段 QT离散度 (QTd)变化对判断预后的临床价值。方法 :5 6例MI患者病情好转后 ,于入院第 6周 9时、2 1时各做同步 12导联心电图 1份 ,当日 8时进行 2 4h动态心电图检查 ,了解 QTd变化及其他检测结果 ,重点分析 6～ 12时及 18～ 2 4时室性心律失常、心肌缺血与 QTd改变之间的关系并随访 1年。结果 :患者 QTd、QTcd明显高于国内报道正常值。且 9时 QTd高于 2 1时 QTd(P <0 .0 1) ,91.1% (5 1例 )有室性心律失常 ,85 .7% (4 8例 )有心肌缺血。 6～ 12时为上述情况出现的高峰期 ,与 QTd密切相关。随访期内死亡 12例 ,心源性猝死 9例 ,6例死于 6～ 12时。结论 :不同时段 QTd延长 ,可能与心肌缺血有关 ,及时了解其变化 ,有助于预报恶性室性心律失常 。

Objective:To evaluate the clini ca l value of QT dispersion for predicting the incidence of malignant ventricular a rrhythmias and the prognosis in patients with healing myocardial infarction.Method:QT dispersion of 12-lead surface ECG was measured in 56 patients with acute myocardial infarction at 9∶00 and 21∶00 respectively in the sixth week after myocardial infarction, and 24 hour dynamic electrocardi ogram (DCG) was recorded concurrently in those patients. Attention was paid to t he incidence of ventricular arrhythmia and myocardial ischemia in two phases of 6:00～12:00 and 18:00～24:00. One year follow-up survey was carried out in thos e patients.Result:QT and QT dispersion in patients with myocardial in farction were higher than those in normal people. For each patient, QT dispersio n at 9:00 was significantly higher than that at 21:00 (P< 0.01).Ventricu lar arrhythmia occurred in 51 patients ( 91.1%) and myocardial ischemia in 48 patients ( 85.7%). They often occurred in the phase of 6:00～12:00 and corre lated positively with QT dispersion (r= 0.262, 0.394, P< 0.05 ). During 1 year follow-up, 12 patients died. Among them, 9 patients died of ca rdiac sudden death due to malignant ventricular arrhythmias, 6 patien ts died in the phase of 6:00～12:00.Conclusion:The prolong ed QT dispersion in different phases is possibly associated with myocardial isch emia. Measuring QT dispersion timely helps to predict the incidence of malignant ventricular arrhythmia and cardiac sudden death.