Estimation and removal of baseline drift in the electrocardiogram.

Estimation procedures for baseline drift have been developed using cubic spline, polynomial, and rational functions. In a test set of 50 electrocardiograms (ECGs), each of 2.5-sec duration, baseline stability was significantly improved by application of any of these methods, except rational function approximation. Amplitude histograms of clinical ECGs after subtraction of estimated baseline distortions showed only small baseline variations over the recording period. For a quantitative validation of the estimation procedures, 10 ECGs with artificial baseline drift were constructed and analyzed by correlation and mean square error calculations. From these comparisons, the polynomial approximation emerged as the most efficient method.