微伏极T波电交替对心肌梗死急性期患者发生恶性心律失常的预测价值

Prognostic value of microvolt T-wave alternans to life-threatening tachyarrhythmia in patients with acute myocardial infarction

目的评估微伏极T波电交替（MTWA）能否预测急性心肌梗死早期患者恶性心律失常的发生。方法起病7d内的急性ST段抬高型心肌梗死患者175例入选，根据起病12h内有无行直接经皮冠脉介入治疗（PCI）分为两亚组：Ia组（n=68行直接PCI），Ib组（n=107未行直接PCI）。另选无心肌梗死来我院健康体检者82例作为对照组。所有入选者均做动态心电图用时域分析法检测MTWA最大值，用超声心动图检测左心室射血分数（LVEF），用心室晚电位分析仪检测心室晚电位，观察住院期间有无恶性心律失常发生，并比较上述这些指标组间有无差异，用Logistic回归分析筛选恶性心律失常的预测因子。结果心肌梗死组合并糖尿病者高于对照组，Ib组合并糖尿病者高于Ia组。急性心肌梗死组恶性心律失常发生率、心室晚电位阳性率和MTWA最高值均高于对照组，而LVEF值低于对照组。急性心肌梗死两亚组间比较，Ib组恶性心律失常发生率、心室晚电位阳性率和MTWA最大值均高于Ia组，而LVEF值低于Ia组。Logistic回归分析结果显示MTWA最大值、LVEF、心室晚电位阳性率和有无糖尿病是患者是否发生恶性心律失常的独立预测因子，相关系数R分别为0．34、0．29、0．21、0．13，相对危险度（OR）分别为2．82、1．55、1．36、0．87，MTWA的相关性最强（R=0．34），相对危险度最高（OR=2．82）。当LVEF和心室晚电位进入回归方程时，决定系数R^20．448，增加MTWA最大值进入回归方程后，决定系数R^2显著增加至0．628。结论MTWA最大值、LVEF和心室晚电位是早期急性心肌梗死患者恶性心律失常发生的预测因子，MTWA的预测价值优于LVEF和心室晚电位。如果三者联合运用能更好地预测早期急性心肌梗死患者恶性心律失常发生。

Objective The aim of the study was to explore whether the microvoh T-wave alternans （MTWA） can predict the life-threatening tachyarrhythmia after early acute myocardial infarction （AMI）. Methods Two hundred and fifty-seven subjects were enrolled in present study. One hundred and seventy-fiye consecutive patients with ST-elevation AMI within 7 days, of which 68 received primary pereutaneous coronary intervention （PCI） as Ia group and 107 without PCI as Ib group. Eighty-two persons without MI were enrolled as the control group. The MTWA was analyzed using the modified moving average method by 24 h digital ambu- latory electrocardiogram. Left ventricular ejection fraction （LVEF） was evaluated by echocardiography. Late po- tentials （LP） were analyzed by signal averaged electrocardiogram. The primary outcome was ventricular tachya- rrhythmia/ventricular fibrillation （VT/VF） during the hospital. These indexes were compared among the three groups and the predictors of VT/VF were evaluated by Logistic regression. Results The patients with diabetes in AMI group were more than in I b group, and I b group were more in the control group. The MTWA, positive LP and VT/VF evidence in AMI group were higher than in the control group, and in I b group were higher than in I a group too;while the LVEF in AMI group was lower than in the control group and that in I b group was lower than in I a group too. Multivariate analysis identified the following as independent correlates of VT/VF： MTWA, LVEF, LP and diabetes. Correlation R was 0. 34,0. 29,0. 21and 0. 13 respectively, and odds ratio was 2. 82,1.55,1.36 and 0. 87 respectively. The best correlation and odds ratio was the MTWA. Coefficient of determination R^2 was 0. 448 when the LVEF and LP went into regression ,whereas that was 0. 628 when The MTWA, LVEF and LP went into regression. Conclusions The MTWA, LVEF and LP were the predictors of VT/VF in patients with early AMI, and the prognostic value of the MTWA was better than that of the LVEF and LP. The better predictive value was obtained if the MTWA, LVEF and LP were combined.