Stein Phyllis K, Sanghavi Devang, Domitrovich Peter P, Mackey Robert A, Deedwania Prakash
Washington University School of Medicine HRV Lab, 4625 Lindell Blvd., Suite 402, St. Louis, Missouri, 63108, USA.
J Cardiovasc Electrophysiol. 2008 Oct;19(10):1037-42. doi: 10.1111/j.1540-8167.2008.01225.x. Epub 2008 Jun 28.
Exercise microvolt T-wave alternans (TWA) identifies sudden cardiac death (SCD) risk. TWA can be measured from ambulatory ECGs (AECGs) using modified moving average (MMA) method. Whether MMA TWA from AECGs predicts SCD in post-MI patients with left ventricular dysfunction (LVD) is unknown.
EPHESUS enrolled hospitalized post-MI patients with heart failure and/or diabetes with LVD. Before randomization to drug treatment, AECGs were obtained in 493 patients. Of them, 46 died of cardiovascular causes, including 18 of SCD. Patients alive at end of follow-up (N = 92) were matched with 46 nonsurvivors based on age, gender, and diabetes. MMA TWA was analyzed using MARSPC system (GE Healthcare, Milwaukee, WI, USA). The three highest TWA values from artifact-free periods were averaged for AECG channels corresponding to leads V(1) and V(3). SCD prediction was tested with a prespecified 47 microV cutpoint and at a cutpoint maximizing the separation between SCD patients versus survivors or non-SCD.
TWA in either lead was higher for patients with SCD (P < or = 0.05) versus survivors or non-SCD. TWA > or = 47 microV was associated with RR = 5.2 (95%CI = 1.8-13.6, P = 0.002) in V(1) and RR = 5.5 (95% CI = 2.2-13.8, P < 0.001) in V(3) for SCD. The optimal cutpoint for TWA in V(1) was > or = 43 microV (RR = 5.9 [95%CI = 2.2-15.8, P < 0.001]). The optimal cutpoint in V(3) was > or = 47 microV. TWA greater than the optimal cutpoint in either lead was associated with RR = 7.1 (95%CI = 2.7-18.3, P < 0.001) for SCD, with 11 out of 18 patients dying of SCD.
AECG-based TWA measured with MMA is a powerful predictor of SCD in high-risk post-MI patients with LV dysfunction.
运动微伏T波交替（TWA）可识别心脏性猝死（SCD）风险。可使用改良移动平均（MMA）方法从动态心电图（AECG）中测量TWA。来自AECG的MMA TWA是否能预测心肌梗死后左心室功能障碍（LVD）患者的SCD尚不清楚。
EPHESUS研究纳入了因心力衰竭和/或糖尿病伴LVD而住院的心肌梗死后患者。在随机接受药物治疗之前，对493例患者进行了AECG检查。其中46例死于心血管原因，包括18例死于SCD。随访结束时存活的患者（N = 92）根据年龄、性别和糖尿病情况与46例非存活者进行匹配。使用MARSPC系统（美国威斯康星州密尔沃基市通用电气医疗集团）分析MMA TWA。对与V（1）和V（3）导联对应的AECG通道，将无伪迹时段的三个最高TWA值进行平均。使用预先设定的47微伏切点以及使SCD患者与存活者或非SCD患者之间分离度最大化的切点来测试SCD预测情况。
与存活者或非SCD患者相比，SCD患者任一导联的TWA更高（P≤0.05）。对于SCD，V（1）导联TWA≥47微伏时相对危险度（RR）= 5.2（95%可信区间[CI]= 1.8 - 13.6，P = 0.002），V（3）导联RR = 5.5（95% CI = 2.2 - 13.8，P < 0.001）。V（1）导联TWA的最佳切点为≥43微伏（RR = 5.9 [95% CI = 2.2 - 15.8，P < 0.001]）。V（3）导联的最佳切点为≥47微伏。任一导联TWA大于最佳切点与SCD的RR = 7.1（95% CI = 2.7 - 18.3，P < 0.001）相关，18例SCD患者中有11例死亡。
采用MMA测量的基于AECG的TWA是心肌梗死后左心室功能障碍高危患者SCD的有力预测指标。
