QT间期测量的小波分析方法

A Wavelet Transform Based Approach in Measuring QT Interval of ECG

目的 准确获取人体心电信号 (ECG)中的 QT间期值。方法 利用小波变换多尺度多分辨的特点 ,将心电信号进行多尺度分解 ,把不同频带的信号显现在小波分解各个尺度上。特征尺度上准确定位 QRS波及T波的起始点 ,从而获得 QT间期的精确值。结果 1在 2 m V的心电信号上引入峰峰值为 1m V的误差信号 ,利用二进小波进行分解和重构得到相对精确的心电波形 ,测得 QRS波、P波、T波的宽度最大误差分别为 5 .75 % ,5 .2 % ,3.8%。 2用小波分析方法对 MIT/ BIH数据库中的 ECG信号进行处理后 ,测量得到各间期的平均值及标准偏差 ,可以反映出 QT间期及相应各间期的稳定性。结论 人体心电信号随着检测状态及时间的变化具有明显的非平稳性及包含许多干扰的特点。利用小波变换将心电信号进行处理能够获得 QT间期的精确值 。

Objective To acquire accurate parameters of QT interval of ECG signal. Methods The ECG signal is decomposed in multi scales using the multi resolving power of the wavelets transform. The signals with different frequencies were showed in different scales. The onsets of QRS wave and T wave was identified in the characteristic scales to provide accurate parameters of the QT interval. Results ① Precise ECG wave was reconstructed by binary wavelets through adding of 1mV error signal to 2mV ECG signal. The maximal errors of the QRS wave, P wave, and T wave were 5.75%, 5.2%, and 3.8% respectively. ② The averages and standard deviations derived from the ECG signal of MIT/BIH disposed by wavelets reflected the stabilities of QT and other intervals. Conclusion The ECG signals are obviously unbalanced and contain many noises in the process of detecting. The QT interval can be captured perfectly by wavelets decomposed ECG signals, which provides more accurate diagnostic information for medical practice.