Optimal Frequency and Bandwidth for FIR Bandpass Filter for QRS Detection

The MIT-BIH arrhythmia database (48 ECG records of 30 min each) was used to find out, experimentally, which combination of centre frequency and bandwidth is `optimal´ for a pre-emphasis digital Finite Impulse Response (FIR) band-pass filter for QRS detection. An exhaustive search was performed for centre frequencies ranging from 13 to 20 Hz and for band-widths from 5 to 12 Hz, at integer values of 1 Hz for both. The criterion for optimality was simply the filter that, coupled with a simple threshold detector, produced the minimum number of errors (defined as the sum of false-positives and false-negatives). For the whole MIT-BIH database the `optimum´ point was found to be that where centre frequency, fo=19 Hz and bandwidth, BW=9 Hz.