Ono Takashi, Yasuda Yoshifumi, Ito Tomonori, Barros Allan K, Ishida Koji, Miyamura Miharu, Yoshizawa Makoto, Yambe Tomoyuki
Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya 464-8601, Japan.
Tohoku J Exp Med. 2004 Mar;202(3):181-91. doi: 10.1620/tjem.202.181.
The purpose of this study was to assess the validity of an adaptive filter, the scaled Fourier linear combiner (SFLC), in the impedance cardiography (ICG). Eight healthy males underwent constant-load bicycle exercise at different intensities from unloaded to near maximal intensity. The stroke volume (SV) and cardiac output (Q) measured by ICG at each condition were compared with those by the CO2 rebreathing method. We found that the noises were greatly reduced in the impedance waveform and that the inflection points, so-called the B- and X-points, were clearly detected even during strenuous exercise using the SFLC. Although a high correlation was observed between Qs measured by the two methods, the mean values of Qs in each method differed significantly and the regression line also differed significantly from the identity line. Likewise, a significant correlation was observed between SVs obtained by the two methods, but a significant difference in the group mean values and a trend of the regression line were observed. These findings suggest that the use of SFLC in ICG improves the performance in eliminating the noises and in detecting the inflection points in the waveform, thereby contributing to the accurate and beat-to-beat measurements of SV and Q especially during exercise.
本研究的目的是评估一种自适应滤波器——缩放傅里叶线性组合器（SFLC）在阻抗心动图（ICG）中的有效性。八名健康男性进行了从无负荷到接近最大强度的不同强度的恒负荷自行车运动。将每种情况下通过ICG测量的每搏输出量（SV）和心输出量（Q）与通过二氧化碳重呼吸法测量的结果进行比较。我们发现，使用SFLC时，即使在剧烈运动期间，阻抗波形中的噪声也会大大降低，并且能够清晰地检测到所谓的B点和X点等拐点。尽管两种方法测量的Qs之间观察到高度相关性，但每种方法中Qs的平均值存在显著差异，回归线也与恒等线有显著差异。同样，两种方法获得的SVs之间观察到显著相关性，但组平均值存在显著差异，并且观察到回归线的趋势。这些发现表明，在ICG中使用SFLC可提高消除噪声和检测波形中拐点的性能，从而有助于特别是在运动期间准确地逐搏测量SV和Q。
