Interpretation of coarse-graining of Lempel-Ziv complexity measure in ECG signal analysis

Lempel-Ziv (LZ) complexity measure has been applied to classify ventricular tachycardia (VT) and ventricular fibrillation (VF). The coarse-graining process plays a crucial role in the LZ complexity measure analysis, which directly affects the separating performance of VT and VF in ECG signal analysis. The question of different coarse-graining approaches interpretability in ECG signal analysis and their influence on the performance of ECG classification have not yet been previously addressed in the literature. In this paper, we present four coarse-graining process approaches, K-Means, Mean, Median and Mid-point. Our test shows that K-Means algorithm is superior to the other three approaches in VT and VF separation rate, Particularly, optimum performance is achieved at a 8-second window length.