Microcomputer-based measurement of beat-to-beat intervals and analysis of heart rate variability.

This paper presents detailed information about a small, low-cost computerized system for on-line data processing which may easily be adapted to various problems. In the application described, the system operates as a heart detector and analyzer providing ECG signal filtering, measurement of beat-to-beat intervals (resolution: 1 ms), elimination of both artifacts and extrasystoles, and statistical analysis. All data and results are stored on magnetic tape and printed. This device proved to be a valuable tool in the investigation of heart rate abnormalities, which seem to indicate the presence of autonomic dysfunction observed in long-term diabetes mellitus. Preliminary results show that the decrease of normal beat-to-beat variation in diabetics is highly correlated with diabetic neuropathy and microangiopathy of the eye.