Automatic Recognition of Electrocardiographic Waves by Digital Computer

A digital computer program for automatic recognition of electrocardiographic waves has been described. First, a filtering procedure was applied in order to eliminate extraneous noise. Consequently, the spatial velocity derived from three orthogonal electrocardio-graphic leads was determined for an entire cardiac cycle. It was found that a critical value of 3 µV per msec, was never exceeded during T-P intervals, P-R segments, and S-T segments. This limit for the spatial velocity could be used to indicate the beginning and end of electrocardiographic waves. The method was tested in a series of 395 records. The computer failed in 1.3 per cent of all expected measurements. "With one exception, failures were encountered only in eases with cardiac arrhythmias but not with regular sinus rhythm. Comparison between computed and visual time measurements showed close agreement, especially when limits of visual accuracy and beat-to-beat variations in wave duration were taken into account. The described procedure can serve as the basis for a complete electrocardiographic analysis by digital computer.