as the interval between qrs waves and t wave in ecg, qt interval represents the depolarization of ventricle.
qt间期指心电波形中qrs波起点到t波终点这一段所对应的时间间隔,代表心室去极化过程。
positions of 18 monitoring leads electrodes can reflect objective change of st-t and qrs waves of routine 18-lead electrocardiogram. this method may be used widely.