The effects of different filters on the results of the signal-averaged electrocardiogram analysis

In order to investigate the effect of different filtering techniques on the time-domain signal averaged ECG (SAECG), recordings of 1192 subjects, were analysed using both Butterworth and Del Mar filter at 10 Hz high pass filter setting. Compared with the Butterworth filter, the Del Mar filter (A) led to a systematic difference of +8% in total QRS duration, (B) was equally powerful in distinguishing between the patients with and without post infarction ventricular tachycardia, and (C) was significantly better than those survivors of acute infarction who were at high risk of arrhythmic events. In conclusion, the use of different filters may produce discordant results of SAECG analysis. Normal and abnormal values various types of SAECG recording and analysis have to be established individually for different equipment