Adachi K, Ohnishi Y, Shima T, Yamashiro K, Takei A, Tamura N, Yokoyama M
First Department of Internal Medicine, Kobe University School of Medicine, Japan.
J Am Coll Cardiol. 1999 Aug;34(2):374-80. doi: 10.1016/s0735-1097(99)00208-9.
The aim of this study was to clarify the clinical significance and the determinant of microvolt-level T-wave alternans (TWA) in patients with dilated cardiomyopathy (DCM).
The prevention of sudden death in patients with DCM remains the therapeutic target. T-wave alternans has been proposed as a powerful tool for identification of patients at high risk for ventricular arrhythmias and sudden death in coronary artery disease.
In 58 DCM patients, TWA was measured during bicycle exercise testing using a CH 2000 system (Cambridge Heart, Bedford, Massachusetts). The New York Heart Association class, signal-averaged electrocardiogram, QT dispersion, left ventricular end-diastolic diameter (LVDd) and percent fractional shortening detected by echocardiogram and the grade of the ventricular arrhythmia were obtained in all patients.
T-wave alternans was positive in 23 patients (TWA+ group), negative in 25 (TWA- group) and indeterminate in 10. Univariate analysis showed that the percentage of patients with ventricular tachycardia (VT) and the LVDd in the TWA+ group was significantly higher than those in the TWA- group (61% vs. 8%, p < 0.001 and 65 +/- 11 mm vs. 58 +/- 8 mm, p < 0.05, respectively). The sensitivity, specificity and predictive accuracy of TWA for VT were 88%, 72% and 77%, respectively. Multivariate analysis showed that the presence of VT was a major independent determinant of TWA in patients with DCM (p = 0.003).
T-wave alternans was closely related to VT in patients with DCM. T-wave alternans is a useful noninvasive test for identifying high risk patients with DCM who have VT.
本研究旨在阐明扩张型心肌病（DCM）患者中微伏级T波交替（TWA）的临床意义及决定因素。
预防DCM患者猝死仍是治疗目标。T波交替已被认为是识别冠心病室性心律失常和猝死高危患者的有力工具。
对58例DCM患者，使用CH 2000系统（剑桥心脏公司，马萨诸塞州贝德福德）在自行车运动试验期间测量TWA。获取所有患者的纽约心脏协会心功能分级、信号平均心电图、QT离散度、左心室舒张末期内径（LVDd）、超声心动图检测的左心室缩短分数百分比以及室性心律失常分级。
23例患者T波交替阳性（TWA+组），25例阴性（TWA-组），10例不确定。单因素分析显示，TWA+组室性心动过速（VT）患者百分比和LVDd显著高于TWA-组（分别为61%对8%，p<0.001；65±11mm对58±8mm，p<0.05）。TWA对VT的敏感性、特异性和预测准确性分别为88%、72%和77%。多因素分析显示，VT的存在是DCM患者TWA的主要独立决定因素（p = 0.003）。
DCM患者中T波交替与VT密切相关。T波交替是识别有VT的DCM高危患者的一种有用的非侵入性检查。
