Spatiotemporal Permutation Entropy as a Measure for Complexity of Cardiac Arrhythmia

• Main Authors: Alexander Schlemmer, Sebastian Berg, Thomas Lilienkamp, Stefan Luther, Ulrich Parlitz
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2018-05-01
• Series: Frontiers in Physics
• Subjects: permutation entropy; cardiac arrhythmia; Fenton-Karma simulation; complexity; excitable media; phase singularities
• Online Access: https://www.frontiersin.org/article/10.3389/fphy.2018.00039/full

Permutation entropy (PE) is a robust quantity for measuring the complexity of time series. In the cardiac community it is predominantly used in the context of electrocardiogram (ECG) signal analysis for diagnoses and predictions with a major application found in heart rate variability parameters. In this article we are combining spatial and temporal PE to form a spatiotemporal PE that captures both, complexity of spatial structures and temporal complexity at the same time. We demonstrate that the spatiotemporal PE (STPE) quantifies complexity using two datasets from simulated cardiac arrhythmia and compare it to phase singularity analysis and spatial PE (SPE). These datasets simulate ventricular fibrillation (VF) on a two-dimensional and a three-dimensional medium using the Fenton-Karma model. We show that SPE and STPE are robust against noise and demonstrate its usefulness for extracting complexity features at different spatial scales.