The aim of this study was to compare two approaches for estimating the spectrum of the surface ECG during ventricular fibrillation (VF): the fast Fourier transform (FFT) and maximum entropy spectral analysis (MESA). The first 10 s of 10 recordings of clinical VF sampled at 250 Hz were separated into 1 s epochs for analysis by the FFT, zero padded FFT and Burg algorithm with 5, 10, 20 and 50 coefficients. The mean difference in dominant frequency between the FFT and Burg algorithm with 50 coefficients was 0.04 Hz (SD 0.56). The mean frequency of the dominant peak in the spectrum of VF can be measured accurately using either the FFT, zero padded FFT or MESA with a model order of more than 10. The overall accuracy of the standard FFT when compared to MESA is not limited by its poor resolution as long as results are averaged over large numbers of recordings.
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机译:这项研究的目的是比较心室纤颤(VF)期间估计表面ECG频谱的两种方法:快速傅立叶变换(FFT)和最大熵频谱分析(MESA)。以250 Hz采样的10个临床VF记录的前10 s被分成1 s epoch,以进行FFT,零填充FFT和Burg算法分析,系数分别为5、10、20和50。具有50个系数的FFT和Burg算法之间的主频平均差为0.04 Hz(SD 0.56)。可以使用FFT,零填充FFT或模型级大于10的MESA精确测量VF频谱中主峰的平均频率。与MESA相比,标准FFT的整体精度不受以下限制:只要对大量录音进行平均,其分辨率就很差。
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