Comparison between permutation and coarse-grained entropy approaches for the assessment of short-term complexity of heart period variability

The study compares permutationand coarse-grained entropy approaches for the assessment of short-term complexity of the cardiovascular control from heart period (HP) variability recordings. Approaches were applied to simulations and to HP variability series recorded during complete vagal blockadeobtained via administration of a high dose of atropine (AT). Differences between the estimated complexity indexesderived from both simulations and real data indicated that permutationentropy has a larger sensitivity to noise than coarse-grained entropy. We recommend caution in applying permutationentropy in presence of short HP variability series characterized by a low signal-to-noise ratio such as after complete vagal blockadeinduced by AT.