Understanding irregularity characteristics of short-term HRV signals using sample entropy profile

Abstract

Sample entropy (SampEn), a popularly used 'regularity analysis' tool, has restrictions in handling short-term segments (largely N ≤ 200) of heart rate variability (HRV) data. For such short signals, the SampEn estimate either remains undefined or fails to retrieve 'accurate' regularity information. These limitations arise due to the extreme dependence of SampEn on its functional parameters, in particular the tolerance r. Evaluating SampEn at a single random choice of parameter r is a major cause of concern in being able to extract reliable and complete regularity information from a given signal. Here, we hypothesize that, finding a complete profile of SampEn (in contrast to a single estimate..