QRS complex detection in digital EKG signals using the Hilbert transform

This paper investigates the use of the Hilbert transform in locating the QRS complex in an electrocardiogram (EKG) signal. Two methods are proposed and evaluated. One method uses the Hilbert transform as a zero crossing detector on the first derivative of the EKG signal. The second uses the Hilbert transform to calculate the envelope of the signal. The two methods were tested on a standard database.; The Hilbert transform is calculated in two ways. One is in the frequency-domain via the discrete Fourier transform (DFT). The other uses an FIR filter to approximate the Hilbert transform. Both ways were implemented and evaluated.; Both methods were successful in detecting the location of QRS complexes within 100ms. The derivative based method had an average error rate of 6.55%. The envelope based method had an average error rate of 5.79%. Additionally, each method was evaluated for its effectiveness in detecting QRS complexes in abnormal beats.