Stanford University School of Medicine, Stanford, CA, USA.
Am Heart J. 2012 Mar;163(3):354-64. doi: 10.1016/j.ahj.2011.11.021.
Prior studies have indicated that the magnitude of risk association of microvolt T-wave alternans (MTWA) testing appears to vary with the population studied. We performed a meta-analysis to determine the ability of MTWA to modify risk assessment of ventricular tachyarrhythmic events (VTEs) and sudden cardiac death (SCD) across a series of patient risk profiles using likelihood ratio (LR) testing, a measure of test performance independent of disease prevalence.
We identified original research articles published from January 1990 to January 2011 that investigate spectrally derived MTWA. Ventricular tachyarrhythmic event was defined as the total and arrhythmic mortality and nonfatal sustained or implantable cardioverter-defibrillator-treated ventricular tachyarrhythmias. Summary estimates were created for positive and nonnegative MTWA results using a random-effects model and were expressed as positive (LR+) and negative (LR-) LRs.
Of 1,534 articles, 20 prospective cohort studies met our inclusion criteria, consisting of 5,945 subjects predominantly with prior myocardial infarction or left ventricular dysfunction. Although there was a modest association between positive MTWA and VTE (relative risk 2.45, 1.58-3.79) and nonnegative MTWA and VTE (3.68, 2.23-6.07), test performance was poor (positive MTWA: LR+ 1.78, LR- 0.43; nonnegative MTWA: LR+ 1.38, LR- 0.56). Subgroup analyses of subjects classified as prior VTE, post-myocardial infarction, SCD-HeFT type, and MADIT-II type had a similar poor test performance. A negative MTWA result would decrease the annualized risk of VTE from 8.85% to 6.37% in MADIT-II-type patients and from 5.91% to 2.60% in SCD-HeFT-type patients.
Despite a modest association, results of spectrally derived MTWA testing do not sufficiently modify the risk of VTE to change clinical decisions.
先前的研究表明，微伏 T 波交替（MTWA）检测的风险关联程度似乎随研究人群而变化。我们进行了一项荟萃分析，以确定 MTWA 在一系列患者风险特征中改变室性快速性心律失常事件（VTE）和心源性猝死（SCD）风险评估的能力，使用似然比（LR）检测，这是一种独立于疾病流行率的测试性能衡量标准。
我们确定了 1990 年 1 月至 2011 年 1 月发表的原始研究文章，这些文章调查了光谱衍生的 MTWA。室性快速性心律失常事件定义为总心律失常死亡率和非致命性持续性或植入式心脏复律除颤器治疗的室性心动过速。使用随机效应模型为阳性和非负 MTWA 结果创建汇总估计，并表示为阳性（LR+）和阴性（LR-）LR。
在 1534 篇文章中，20 项前瞻性队列研究符合我们的纳入标准，包括 5945 名主要患有既往心肌梗死或左心室功能障碍的患者。尽管阳性 MTWA 与 VTE 之间存在适度的关联（相对风险 2.45，1.58-3.79），而非负 MTWA 与 VTE 之间存在适度的关联（3.68，2.23-6.07），但测试性能不佳（阳性 MTWA：LR+1.78，LR-0.43；非负 MTWA：LR+1.38，LR-0.56）。对分类为既往 VTE、心肌梗死后、SCD-HeFT 型和 MADIT-II 型的患者进行亚组分析，结果也显示出类似的测试性能不佳。在 MADIT-II 型患者中，阴性 MTWA 结果可将 VTE 的年化风险从 8.85%降低至 6.37%，在 SCD-HeFT 型患者中从 5.91%降低至 2.60%。
尽管存在适度的关联，但光谱衍生的 MTWA 检测结果并不能充分改变 VTE 的风险，从而改变临床决策。
