[A study on frequency characteristics of filter for detecting high frequency components of QRS complex and its...

A method to detect the high frequency component of QRS complex was developed and the mode of intraventricular conduction was analyzed from its sequential changes. An originally developed subtraction method was used to diminish the transient phenomenon related to phase shift and to obtain easily changeable filtering characteristics. The subjects included normal healthy persons (N), persons having right or left bundle branch block (R and L) and ventricular premature contraction of R or L type (VR and VL). Three components, initial low, mid high and terminal low amplitude were obtained in the N group. In the R group, mid component was lower and duration of the terminal component was longer than in the N group. In the L group, mid and terminal components were not clearly discriminated. Further, their amplitudes were low and duration of each component was markedly prolonged. In the VR and VL groups, the amplitude of the initial component was low and its duration was prolonged. From these findings, the excitation wave through the normal conduction system was short in duration and relatively high in amplitude and includes high frequency component. As contrasted, the duration was prolonged and the amplitude was low in conduction disturbance, seen in bundle branch block or ventricular premature contraction. Thus, the mode of intraventricular conduction could be defined by this newly developed method.