Steinbigler Peter, Haberl Ralph, Steinbeck Gerhard
Medical Hospital I, University of Munich, München, Germany.
Pacing Clin Electrophysiol. 2004 Feb;27(2):156-65. doi: 10.1111/j.1540-8159.2004.00405.x.
Conventional methods using Holter ECG recordings for noninvasive risk stratification are limited in patients with idiopathic dilated cardiomyopathy (IDC) prone to ventricular fibrillation (VF) having atrial fibrillation (AF) or bundle branch block (BBB). We therefore investigated, whether spectral assessment of beat-to-beat alternations of repolarization is associated with VF in these patients. Twenty-four-hour Holter ECG recordings in 462 patients with IDC were used. The VF group comprised of 64 consecutive patients who survived cardiac arrest, the no VF group consisted of 398 consecutive patients without a history of malignant ventricular arrhythmia. One hundred patients with ischemic cardiomyopathy (ICM) served as a control group. In each patient, 1,024 consecutive T waves were aligned using cross correlation methods. Two-dimensional Fourier transform (2D FFT) used the data matrix of 1,024 consecutive 200-ms segments centered to the T wave peak. Power spectra of the 2D FFT revealed the frequency content of the T wave in the first dimension and the periodicity of this frequency content in the second dimension. The ratio between periodic frequency contents and the sum of nonperiodic and periodic frequency contents between 0.5 and 50 Hz is equal to the T wave spectral variance (TWSV) index. Thus, TWSV index = 0 would mean that all 1,024 T waves are identical and TWSV index = 1 would mean that the 1,024 T waves are totally variable. The TWSV index was significantly higher in the VF group (0.93 +/- 0.14) than in the no VF group (0.53 +/- 0.13, P < 0.01). The best cutoff between the VF and the no VF group was achieved by using a TWSV index of 0.75 (sensitivity = 89%, specificity = 78%). No significant differences were observed between patients with and without AF or with and without BBB, and between patients with IDC and ICM. Even in the presence of BBB or AF spectral assessment of T wave alternations by TWSV index using 2D FFT in Holter ECG recordings, allows the identification of patients with IDC at risk for VF.
对于患有特发性扩张型心肌病（IDC）且容易发生心室颤动（VF）并伴有心房颤动（AF）或束支传导阻滞（BBB）的患者，使用动态心电图记录进行无创风险分层的传统方法存在局限性。因此，我们研究了复极逐搏交替的频谱评估是否与这些患者的室颤相关。我们使用了462例IDC患者的24小时动态心电图记录。室颤组由64例心脏骤停存活的连续患者组成，无室颤组由398例无恶性室性心律失常病史的连续患者组成。100例缺血性心肌病（ICM）患者作为对照组。在每位患者中，使用互相关方法对1024个连续的T波进行对齐。二维傅里叶变换（2D FFT）使用以T波峰值为中心的1024个连续200毫秒段的数据矩阵。2D FFT的功率谱在第一维度上揭示了T波的频率成分，在第二维度上揭示了该频率成分的周期性。周期频率成分与0.5至50 Hz之间的非周期和周期频率成分总和之比等于T波频谱方差（TWSV）指数。因此，TWSV指数 = 0意味着所有1024个T波相同，TWSV指数 = 1意味着1024个T波完全可变。室颤组的TWSV指数（0.93±0.14）显著高于无室颤组（0.53±0.13，P < 0.01）。使用0.75的TWSV指数可实现室颤组与无室颤组之间的最佳截断值（敏感性 = 89%，特异性 = 78%）。在有或无AF、有或无BBB的患者之间，以及IDC患者和ICM患者之间均未观察到显著差异。即使存在BBB或AF，在动态心电图记录中使用2D FFT通过TWSV指数对T波交替进行频谱评估，也能够识别出有室颤风险的IDC患者。
