Pham Quan, Quan Kara J, Rosenbaum David S
Department of Medicine, The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH 44109-1998, USA.
J Electrocardiol. 2003;36 Suppl:75-81. doi: 10.1016/j.jelectrocard.2003.09.018.
Sudden cardiac death (SCD) is a leading cause of cardiovascular mortality. Therefore, identifying patients at highest risk for SCD is crucial. Conventional noninvasive markers of SCD are inadequate because of low positive predictive value. The presence of visible T-wave alternans (TWA) on electrocardiogram often predicts the occurrence of lethal ventricular arrhythmias. Signal processing methods have made it possible to detect microvolt-level and visually inapparent TWA on electrocardiogram. TWA is caused by underlying regional inhomogeneities of ventricular repolarization, which predispose patients to have ventricular arrhythmias. Microvolt TWA provoked either by atrial pacing, pharmacological stress, or exercise is a promising marker of arrhythmia vulnerability. Several large trials have shown TWA to be comparable or superior to other noninvasive markers and electrophysiologic study in the prediction of SCD. The patient populations in these trials include post myocardial infarction, both ischemic and nonischemic heart failure, and suspected arrhythmias. Prospective trials regarding benefits of implantation of cardioverter-defibrillator therapy based on TWA results are ongoing.
心脏性猝死（SCD）是心血管疾病死亡的主要原因。因此，识别SCD高危患者至关重要。由于阳性预测值较低，传统的SCD无创标志物并不充分。心电图上可见的T波交替（TWA）常可预测致死性室性心律失常的发生。信号处理方法已使在心电图上检测微伏级且肉眼不可见的TWA成为可能。TWA由心室复极潜在的局部不均一性引起，这使患者易发生室性心律失常。心房起搏、药物负荷试验或运动诱发的微伏TWA是心律失常易感性的一个有前景的标志物。几项大型试验表明，在SCD预测方面，TWA与其他无创标志物及电生理检查相当或更优。这些试验中的患者群体包括心肌梗死后患者、缺血性和非缺血性心力衰竭患者以及疑似心律失常患者。基于TWA结果进行植入式心脏复律除颤器治疗获益的前瞻性试验正在进行。
