Mizukami Kazuya, Yokoshiki Hisashi, Mitsuyama Hirofumi, Watanabe Masaya, Tenma Taro, Kamada Rui, Takahashi Masayuki, Sasaki Ryo, Maeno Motoki, Tsutsui Hiroyuki
Department of Cardiovascular Medicine, National Hospital Organization Hokkaido Medical Center, Yamanote 5-7-1-1, Nishi-ku, Sapporo 063-0005, Japan.
Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo 060-8638, Japan.
J Arrhythm. 2017 Jun;33(3):214-219. doi: 10.1016/j.joa.2016.08.005. Epub 2016 Oct 1.
Wavelet is a morphology-based algorithm for detecting ventricular tachycardia. The electrogram (EGM) source of the Wavelet algorithm is nominally programmed with the Can-RV coil configuration, which records a far-field ventricular potential. Therefore, it may be influenced by myopotential interference.
We performed a retrospective review of 40 outpatients who had an implantable cardioverter-defibrillator (ICD) with the Wavelet algorithm. The percent-match score of the Wavelet algorithm was measured during the isometric chest press by pressing the palms together. We classified patients with percent-match scores below 70% due to myopotential interference as positive morphology change, and those with 70% or more as negative morphology change. Stored episodes of tachycardia were evaluated during the follow-up.
The number of patients in the positive morphology change group was 22 (55%). Amplitude of the Can-RV coil EGM was lower in the positive morphology change group compared to that in the negative group (3.9±1.3 mV vs. 7.4±1.6 mV, =0.0015). The cut-off value of the Can-RV coil EGM was 5 mV (area under curve, 0.89). Inappropriate detections caused by myopotential interference occurred in two patients (5%) during a mean follow-up period of 49 months, and one of them received an inappropriate ICD shock. These patients had exhibited positive morphology change.
The Wavelet algorithm is influenced by myopotential interference when the Can-RV coil EGM is less than 5 mV.
小波变换是一种基于形态学的室性心动过速检测算法。小波算法的心电信号（EGM）源通常采用Can-RV线圈配置进行编程，该配置记录的是远场心室电位。因此，它可能会受到肌电位干扰的影响。
我们对40例植入了带有小波算法的植入式心脏复律除颤器（ICD）的门诊患者进行了回顾性研究。在等长胸部按压时，通过双手掌心相对按压来测量小波算法的百分比匹配分数。我们将因肌电位干扰导致百分比匹配分数低于70%的患者分类为阳性形态改变，而将分数在70%及以上的患者分类为阴性形态改变。在随访期间对存储的心动过速发作情况进行评估。
阳性形态改变组患者有22例（55%）。阳性形态改变组Can-RV线圈EGM的幅度低于阴性组（3.9±1.3 mV对7.4±1.6 mV，P = 0.0015）。Can-RV线圈EGM的截断值为5 mV（曲线下面积，0.89）。在平均49个月的随访期内，有2例患者（5%）因肌电位干扰出现不适当检测，其中1例接受了不适当的ICD电击。这些患者表现出阳性形态改变。
当Can-RV线圈EGM小于5 mV时，小波算法会受到肌电位干扰的影响。
