Session P76.5

Non-Linear Analysis of the Main Atrial Wave to Estimate Organization in Paroxysmal Atrial Fibrillation

R Alcaraz*, JJ Rieta

Universidad de Castilla-La Mancha
Cuenca, Spain

A new method to study if an AF episode terminates spontaneously or not is presented in this contribution. The methodology is based on analyzing the increase of atrial activity (AA) organization prior to spontaneous AF termination. The organization varies as a consequence of the descending number of reentries wandering the atrial tissue. The analysis was carried out noninvasively through the use of surface electrocardiogram (ECG) recordings. Sample entropy (SampEn) was selected as a non-linear regularity index. Because noise and ventricular residues degrade SampEn-based organization estimation, therefore the use of selective filtering adapted to the dominant atrial frequency to get the main atrial wave (MAW) notably improved results. The MAW can be considered as the signal associated to the main atrial reentry, its wavelength being the inverse of the dominant atrial frequency.
The methodology was tested making use of 50 one minute ECG recordings, available at Physionet. This database included 26 non-terminating AF episodes, which continued in AF for at least one hour following the end of the excerpt, and 24 AF episodes terminating immediately after the end. 10 labelled recordings of each group formed a learning set. A test set was composed with the remaining 30 recordings. MAW organization analysis was applied to the learning set, and 100% sensitivity and 90% specificity were obtained. The ROC curve provided 0.0891 as optimum SampEn discrimination threshold between terminating and non-terminating AF sets. Using this threshold, 27 out 30 (90%) test signals were correctly discriminated. Therefore, the AF behaviour of 46 out 50 recordings (92%) was correctly predicted. The terminating episodes (0.0747±0.0156) presented lower SampEn values than the non-terminating (0.1047±0.0135). Indeed, both paroxysmal AF groups were statistically distinguishable (p=2.45•10^(-9)). These obtained outcomes allow to conclude that the main atrial wave, and therefore, the main atrial reentry, contains the most relevant information about spontaneous AF termination. Moreover, this clinical relevant information can be extracted through non-linear regularity analysis of non-invasive recordings.

(Abstract Control Number: 212)