Upper envelope detection of ECG signals for baseline wander correction: a pilot study

Abstract

Baseline wander (BW) is a common low frequency artifact in electrocardiogram (ECG) signals. The primecause from which BW arises is the patient’s breathing and movement. To facilitate reliable visual interpretation ofthe ECG and to discern particular patterns in the ECG signal, BW needs to be removed. In this paper, a novel BWremoval method is presented. The hypothesis is based on the observation that ECG signal variation covaries with itsBW. As such, the P, Q, R, S, and T peaks will follow the baseline drift. On this basis, the following proposition istrue: a reliable approximation of the baseline drift can be obtained from the shape derived from the interpolation of oneform of the ECG signal peak (peak envelope). The simulation was performed by adding artificial BW to ECG signalrecordings. The signal-to-noise ratio, mean squared error, and improvement factor criteria were used to numericallyevaluate the performance of the proposed approach. The technique was compared to that of the Hilbert vibrationdecomposition method, an empirical-mode decomposition technique and mathematical morphology. The results of thesimulation indicate that the proposed technique is most effective in situations where there is a considerable distortion inthe baseline wandering.