A real-time system for high-resolution ECG signal averaging usingthe analog SFP alignment technique

摘要

We have developed a real-time, signal averaging system forhigh-resolution ECG, which implements an analog version of the singlefiducial point (SFP) alignment technique. It consist essentially of asecond order, highpass (3 Hz), Butterworth filtering operation appliedto an ECG signal presenting predominantly monopolar QRS complexes. Thisoperation is complemented by zero crossing detection after a signalamplitude threshold level crossing detection. The ECG signal is alsolowpass filtered at 30 Hz to reduce the possibility of ambiguities atthe zero crossing point (the SFP point), in the presence of 60 Hz mainsinterference, or other sources of high frequency noise. The output pulsefrom the analog SFP detector was used as the trigger signal channel in adigital averaging oscilloscope, with a moving average function. Theperformance of this ECG averaging system was evaluated in the spectralrange between 100 and 300 Hz, which is the highest frequency bandwidthof interest in high-resolution electrocardiography. The system wascapable of extracting cardiac electrical events, as short as 2 ms ofduration, in the P-R interval. Hence, it can be appropriate for P-waveand His bundle potentials analysis