Automatic determination of systolic time intervals.

Systolic time intervals (STI), measured non-invasively and during uninterrupted exercise, may contain information about cardiac function. A processing system was developed, which determines STI automatically from 8-sec recordings at each load level. A preprocessing unit provides automatic recording and optimal signal-to-noise ratios. One of the main tasks of the computer program, which is modular in structure and written in FORTRAN IV, is to recognize disturbances and artefacts in the signals. After selection of the complexes, usually with some kind of correlation method, a representative beat is found and the inclination points are localized. Besides these points, indicateions of possible errors are given. Preliminary results indicate that the system may be able to replace the human observer in estimating STI.