Automatic recognition of electrocardiographic waves by digital computer.

A PPLICATIONS of electronic computers .in analysis of medical and biological data are of increasing interest. Large-scale computers offer the advantages of high speed of operation, relatively great accuracy, and extreme versatility. Great amounts of data can be processed in a relatively short time. Thus, extensive statistical studies, mass screening of the population, and data handling in large medical centers should be facilitated. The electrocardiogram was chosen for a pilot study in automatic processing of medical data because of its widespread use as a diagnostic aid. Since even the largest available digital computers are limited in memory capacity , a study in data reduction had to precede the data processing proper. It could be shown that corrected orthogonal three-lead electrocardiograms contain the same clinical information which is being used in conventional 12-lead analysis. 1 Thus, data reduction by a factor of 4:1 could be accomplished without sacrificing clinical information. An automatic procedure for electroeardiographic data conversion from the original analog into digital form has been described previously. 2 Commercially available digital computers can be used, once the electrocardiogram is converted into proper digital format. Since the electrocardiogram consists of several distinct wave forms with different elec-trophysiological significance, the prime objective of any automatic electrocardiographic analysis has to be the development of a computer program which allows automatic recognition of each electrocardiographic wave. Their beginning and end have to be determined accurately in order to obtain measure-ment^ of duration of the complexes and of the time intervals in between them. Although automatic screening of electrocardiograms for certain abnormalities is feasible when the time interval over a complete cardiac cycle is obtained , 3 a detailed analysis of the electro-cardiogram is not possible without proper identification of each wave. An automatic procedure which allows accurate determination of beginning and end of P waves, QRS complexes, and end of T waves is described in the present report. The computer program was successfully tested in a series of 395 elec-trocardiograms. Methods Out of a total of 395 eleetroeardiographie records used for the present study, 173 were read as normal and the remainder as abnormal. The technically poorest records were selected from a tape-recorded electrocardiogram library of approximately 2,500 cases. In most of these tracings, a large amount of interference, such as 60-eycle A.C. noise and/or muscle tremor, was present. It was felt that an automatic wave recognition program could be tested more rigidly with …