Department of Pediatrics, National Taiwan University Hospital and Medical College, National Taiwan University, Taipei, Taiwan.
Int J Cardiol. 2012 Sep 6;159(3):220-4. doi: 10.1016/j.ijcard.2011.02.063. Epub 2011 Mar 21.
Microvolt T wave alternans (MTWA) is an indicator of repolarization heterogeneity and a predictor of ventricular arrhythmia in adults with ischemic or dilated cardiomyopathy. Its implication in patients with repaired tetralogy of Fallot (TOF) is still unclear. This study sought to define the changes and the clinical implication of MTWA in these patients.
Treadmill examination with modified moving average beat analysis (MMA) for MTWA was performed in 101 repaired TOF patients (60.4% male). Data from 103 age- and sex-matched subjects with normal hearts served as controls.
The age at latest follow-up was 20.0 ± 10.6 years. Total repair (60.4% received a transannular right ventricular outflow patch) was performed at a mean age of 4.8(± 5.8) years. After excluding 11 patients with indeterminate data, the MTWA data in 90 TOF patients revealed higher values than those in the control (25.1 ± 14.0 vs. 17.6 ± 9.2 μV, p<0.001). The values were best correlated to the presence of severe pulmonary regurgitation (p=0.006). Ten (9.9%) patients experienced late ventricular arrhythmic events. They tended to have higher MTWA values than those without (34.0 ± 16.5 vs. 24.2 ± 13.5 and p=0.053). Although the MTWA per se would not predict the late arrhythmia events better than QRS duration alone, the positive and negative predictive values increased slightly after adding the MTWA to QRS duration.
MTWA, as measured by MMA, increased in repaired TOF patients particularly in those with severe pulmonary regurgitation and late arrhythmia events. To predict late ventricular arrhythmia, MTWA however was not superior to QRS duration alone.
微伏 T 波电交替（MTWA）是复极异质性的指标，也是缺血性或扩张型心肌病成人室性心律失常的预测因子。但其在法洛四联症（TOF）修复患者中的意义尚不清楚。本研究旨在明确 MTWA 在这些患者中的变化及其临床意义。
对 101 例修复的 TOF 患者（60.4%为男性）进行改良移动平均节拍分析（MMA）的跑步机检查，以进行 MTWA。103 例年龄和性别匹配的正常心脏患者作为对照。
最近随访时的年龄为 20.0±10.6 岁。60.4%的患者接受了跨环右心室流出道补片修复。平均年龄为 4.8（±5.8）岁。排除 11 例数据不确定的患者后，90 例 TOF 患者的 MTWA 值高于对照组（25.1±14.0 比 17.6±9.2μV，p<0.001）。该值与严重肺动脉瓣反流的存在最相关（p=0.006）。10（9.9%）例患者发生晚期室性心律失常事件。他们的 MTWA 值比无事件组高（34.0±16.5 比 24.2±13.5，p=0.053）。尽管 MTWA 本身并不优于 QRS 间期预测晚期心律失常事件，但将 MTWA 与 QRS 间期联合后，阳性和阴性预测值略有增加。
通过 MMA 测量的 MTWA 在修复的 TOF 患者中增加，特别是在那些有严重肺动脉瓣反流和晚期心律失常事件的患者中。预测晚期室性心律失常时，MTWA 并不优于 QRS 间期。
