信号平均心电图三维频谱分析在预测心肌梗塞后室性心动过速中的价值

THREE-DIMENSIONAL SPECTRAL ANALYSIS OF SIGNAL-AVERAGED ELECTROCARDIOGRAM TO IDENTIFY VENTRICULAR TACHYCARDIA AFTER MYOCARDIAL INFARCTION

本文采用三维频谱分析法,对心肌梗塞后伴有室性心动过速(室速)的9例(Ⅰ组),不伴室速的15例(Ⅱ组)及20例正常人(Ⅲ组)进行研究。结果表明,室速组的频谱图在50Hz以上,高振幅的频谱峰仅出现在靠近QRS终末的段上。噪音引起的频谱峰贯穿整个分析段。该法也适用于束支阻滞者。在参数NF值(正常因子)变化上,Ⅰ组与Ⅱ、Ⅲ组间均有显著性差异(P<0.05),而Ⅱ组与Ⅲ组间无明显差异(P>0.05)。该法与时域分析法比较,具有更高的敏感性及特异性。

The study was carried out by Haberl's three-dimensional spectral analysis (25 segments, size 80 ms. time shift 2 ms) in myocardial infarction patients complicated by ventrieular tachyeardia (VT) (Group Ⅰ, 9 eases), non-VT (Group Ⅱ. 15 cases) and healthy controls (Group Ⅲ, 20 cases). A total of 4 patients had bundle branch block. The result showed: In 7 out 9 patients with VT, three-dimensional spectral plots were characterized by spectral peaks > 10 dB in the range of 50-200 Hz in segments only at the end of QRS, but not far outside the QRS; in only 1 out of 15 patients without VT, such peaks could be observed. It could not be observed in 20 healthy subjects. Noise caused spectral peaks throughout all segments. 3 out of 4 patients with bundle branch block were correctly classified with spectral analysis. Significant difference was found in factor of normality (NF) between Group Ⅰ and Group Ⅱ (p<0. 05), Group Ⅰ and Group Ⅲ (p<0. 05), no significant difference was observed between Group Ⅱ and Group Ⅲ (p>0.05). This method is more sensitive and specific than time domain analysis. Thus, it provides better identification of patients with myocardial infarction prone to VT.