Yalın Kıvanç, Gölcük Ebru, Teker Erhan, Yılmaz Ravza, Dursun Memduh, Bilge Ahmet Kaya, Adalet Kamil
Department of Cardiology, İstanbul Faculty of Medicine, İstanbul University; İstanbul-Turkey.
Anadolu Kardiyol Derg. 2014 Aug;14(5):442-7. doi: 10.5152/akd.2014.4918. Epub 2014 Jan 1.
Microvolt T-wave Alternans (TWA) is associated with abnormal repolarization and predicts arrhythmic mortality in patients with previous myocardial infarction (MI). Infarct tissue size and heterogeneity characterized by cardiac magnetic resonance (CMR) has been shown to be associated with arrhythmogenic substrates and sudden cardiac death. Although both delayed enhancement-CMR (de-CMR) and TWA are useful in risk stratification of post-MI patients with preserved left ventricular function, the relationship between scar size and TWA has not studied yet. In this study, we aimed to study the relation between TWA and scar size and characteristics assessed with CMR in post-MI patients (pts) with relatively preserved systolic function presented with nonsustained VT.
This observational cross-sectional study was enrolled 36 post-MI patients with mild-systolic dysfunction and non-sustained ventricular tachycardia. Eight pts were excluded. Both TWA and contrast enhanced CMR were performed. Left ventricular ejection fraction (LVEF), dense scar, peri-infarct zone and total scar masses were assessed and these values to left ventricular (LV) mass ratios were calculated. Infarct ratios and characteristics were determined and compared among patients with negative TWA and those with positive TWA.
For the positive (n=12) vs. negative (n=16) TWA patients there were no significant difference between LVEF (44.9 ± 5.4% vs. 44.0 ± 3.2%, p=NS) and LV masses (121.89 ± 26.56 g vs. 106.14 ± 21.16 g, p=NS). The ratio of scar core to LV mass (3.37 ± 0.68% vs. 3.31 ± 1.01%, p=NS), peri-infarct zone to LV mass (23.61 ± 7.93% vs. 21.64 ± 9.08%, p=NS), total scar to LV mass (26.98 ± 7.86% vs. 24.96 ± 9.62%, p=NS) were all similar.
There were no association between scar size and infarct heterogeneity and prevelance of TWA in post-MI patients with relatively preserved LVEF with non-sustained VT. Our data suggest that these two modalities may reflect different arrhythmogenic mechanisms in this cohort.
微伏级T波交替（TWA）与复极异常相关，并可预测既往心肌梗死（MI）患者的心律失常性死亡。心脏磁共振成像（CMR）所显示的梗死组织大小和异质性已被证明与致心律失常基质及心源性猝死相关。尽管延迟强化CMR（de-CMR）和TWA在左心室功能保留的MI后患者的危险分层中均有用，但瘢痕大小与TWA之间的关系尚未得到研究。在本研究中，我们旨在研究TWA与CMR评估的瘢痕大小及特征之间的关系，这些患者为收缩功能相对保留且出现非持续性室性心动过速（VT）的MI后患者（pts）。
本观察性横断面研究纳入了36例有轻度收缩功能障碍和非持续性室性心动过速的MI后患者。排除8例患者。同时进行了TWA和对比增强CMR检查。评估左心室射血分数（LVEF）、致密瘢痕、梗死周边区和总瘢痕质量，并计算这些值与左心室（LV）质量的比值。确定梗死比值和特征，并在TWA阴性和TWA阳性患者之间进行比较。
对于TWA阳性（n = 12）与阴性（n = 16）的患者，LVEF（44.9±5.4%对44.0±3.2%，p =无显著性差异）和LV质量（121.89±26.56 g对106.14±21.16 g，p =无显著性差异）之间无显著差异。瘢痕核心与LV质量的比值（3.37±0.68%对3.31±1.01%，p =无显著性差异）、梗死周边区与LV质量的比值（23.61±7.93%对21.64±9.08%，p =无显著性差异）、总瘢痕与LV质量的比值（26.98±7.86%对24.96±9.62%，p =无显著性差异）均相似。
在LVEF相对保留且有非持续性VT的MI后患者中，瘢痕大小、梗死异质性与TWA患病率之间无关联。我们的数据表明，在该队列中这两种方法可能反映了不同的致心律失常机制。
