Microcontroller-based real-time QRS detector for ambulatory monitoring

The design and test results of a real-time QRS detector are presented. The detector is based on the Hamilton-Tompkins backward difference algorithm. The QRS detection relies upon the frequency response of a bandpass filter for power-line interference cancellation, base-line wander removal, and high-frequency muscle bursts purging. Differentiation and squaring further improved the signal-to-noise ratio for an adaptive threshold decision stage. The accuracy of the QRS detector was tested with signals like the artificial test waveform established in the ANSI/AAMI EC13-1992 standard but purposely corrupted with noise. An average QRS detection error rate of 0.2% was achieved during the tests.