Combined analysis of time and frequency series regularity applied to the study of atrial fibrillation

Atrial Fibrillation (AF) is the most common arrhythmia encountered in the clinical practice. In this work, a new method based on electrocardiogram (ECG) signal processing is carried out in order to distinguish between AF episodes that will terminate immediately and those that will sustain. This new method is based on a combined analysis of the atrial activity (AA) series regularity in both time and frequency domains. The regularity is measured by using the non-linear regularity estimator Sample Entropy (SampEn). The SampEn of these series of spectral parameters and the SampEn of the AA in the time-domain are studied jointly in a discriminant analysis. In global percentages, forty eight of fifty recordings (96%) were classified correctly by the discriminant analysis, which provided an improvement of 6% with respect to the univariate analysis of SampEn.