本研究比较了两种窗起点对频谱时间标测分析结果的影响。窗起点位于滤波综合ＱＲＳ波终未电压低于４０μＶ处时，其敏感性、特异性、阳性预告值及阴性预告值均高于窗起点位于ＱＲＳ波终点前２０ｍｓ时。窗起点位于ＱＲＳ波终点前２０ｍｓ时，持续性室速／室颤组与健康人组晚电位阳性率无显著差异。证明前者优于后者。 This study compares the impact of two kinds of window start-up on the results of spectral time-mapping analysis. Sensitivity, specificity, positive predictive value and negative predictive value were all higher than those of the window beginning at 20 ms before the end of QRS wave when the window start point was at the voltage of less than 40μV at the end of filtering integrated QRS wave. There was no significant difference in the positive rate of late potentials between continuous ventricular tachycardia / ventricular fibrillation group and healthy people at 20 ms before the end of the window of QRS wave. The former is better than the latter.