[On time-frequency analysis at mid-QRS stage on body surface electrocardiogram].

The advanced technology in signal processing has been utilized for recording high resolution electrocardiogram. It has presented some new valuable informations, possibly reflecting electrical characteristics of myocardium. Detecting ventricular late potential is practical, however, it uses only part of high resolution signals, because of difficulty of dividing into higher frequency components. Therefore, high resolutional signals were analyzed using numerical filter in order to detect and verify higher frequency components at mid-QRS stage on body surface electrocardiogram. Precordial signals were summation-averaged and underwent narrow peak filtering using various peek frequencies increasing stepwisely between 50 Hz and 400 Hz. In conclusion, this minutely analyzing system was able to pick up valuable informations in mid-QRS stage signal. For example, harmonization of peek phases in several frequencies at QRS complex had gaps that suggested abnormality of local myocardium.