In this paper, a new method is proposed for QRS complex detectionusing a special kind of IIR filter called bi-reciprocal lattice wave digital filter (WDF). This filter has some attractive features that make it more efficient than other types of filters.One of these features is its sufficient linear phase in the passband, thus yielding a perfect reconstraction condition. Therefore, it is not required to cascade the designed filter with anall-pass filter for correcting the phase distortion. The coefficients of the designedfilter areachieved by simulating the FIR response suggested in [1].A least square method solution is usedin such simulation with a genetic-based algorithm.A simplified structure for the designed filter is accomplished with less-complex realization. 50records of European ST – T ECG database is classified into four classes (Normal, Left Bundle Branch Block (LBBB), ST segment elevation, and Left Ventricular Hypertrophy (LVH)). By applying the designed filter coefficients into neural network classifier, the results show that the accuracy of the classification process is 95.9 %.