在作者與英國GLASGOW大學合作之正常1555例正常標準傳統心電圖研究顯示出來男性的QRS duration比女性約長8ms。另外由研究的正常英國人195例的平均信號心電圖研究之中也顯示出男比女在filtered QRS duration有10.2ms之差距，但近年來在此方面之研究均由西洋人的數據在中國人先有新加坡有小孩之數據，因此本研究之目的乃在於建立中國人的正常成人平均信號心電圖數據。本實驗共有122名學生及教職員工參與（男105人，女17人），本研究使用之平均信號心電圖儀器為Siemens Elema MEGACART，filter為BUTTERWORTH bi-directional filter，頻率訂在40到250 Hz之間，取樣之Noise level定在0.3 microV以下，通常Sampling均超過300個心律週期以上，本研究中使用的三個主要的參數如下：（1）Total filtered QRS duration （QRSd）（2）LAS40（在40 mtcrnV以下的低幅信號期間）（3）RMS40（最後40mS的根號平方值）本研究結果顯示中國人男女之間QRSd反而女比男大（3.47ms）與以前英國人之研究相比較：RMS40及QRSc在中國人均為女比男大，LAS40男大於女，而在英國人中QRSd，LAS40男比女大，RMS40女比男大，因此可能由於種族因素之差異，由本研究可知平均信號心電圖用來檢測心室遲緩電位必須因民族而有所不同。

　　　　　The results from a previous study on 12-lead ECG in 1555 normal Caucasians by the Glasgowgroup had shown that the QRS duration in men was 8 ms greater than women. The other study onsignal averaged ECG (SAECG) of 195 normal Caucasians also showed that the filtered total QRSduration in men was 10.2 ms greater than women. The purpose of this research is to establish thenormal limits of SAECG in Chinese. In total, 122 normal subjects (105 men and 17 women) were recruited for the present study.The machine used to record signal averaged electrocardiogram is Siemens Elema Megacart ECGrecorder, which adopted the Butterworth bi-directional filter and the frequency range is set at 40250 Hz. Usually, the sampling process is completed after running for more than 300 cardiac cycles.Three time domain parameters of the QRS vector amplitude, namely (1) filtered total QRSduration (QRSd), (2) duration of the low amplitude signals under 40 microV (LAS40), and (3) rootmean square voltage of the last 40 ms (RMS40), were evaluated. In Chinese, filtered total QRS duration in women is 3.47 ms greater than in men. RMS40 andQRSd are greater in women than in men and opposite in LAS40. In Caucasian, men were 10.2 msgreater than women in QRSd and LAS40. Therefore, the racial difference between Chinese andCaucasian is significant.