Abstract: The methods of surface detection of His bundle activity can be generally divided into two kinds. One method uses the technique of serial signal averaging which requires digital averaging of 50-100 sequential cardiac cycles. But it can not record the His bundle signal on a beat-by-beat basis and so it is not effective in clinical applications in that some diseases such as arrhythmia, AV block and less-then-oonstant RR intervals ooour intermittently instead of in every cardiac cycle. The other method can avoid the disad ventages of serial signal averaging by using multiple parallel inputs with amplifications.
The real-time detection of the His bundle activity on a beat-by-beat basis can be achieved. Because of this advantage, the latter method deserves much attention.This paper describes the study of the His bundle activity detection based on the parallel averaging technique in the institute of BME of SUST, and its evaluation for clinical applications.

Key words: surface His bundle electrogram, logical judgment, clinical applications, parallel signal averaging