Non-Linear analysis of the main atrial wave to estimate organization in paroxysmal atrial fibrillation

The analysis of spontaneous Atrial Fibrillation (paroxysmal AF) termination or maintenance could avoid unnecessary therapy and contribute to take the appropriate decisions on its management. The aim of this work is to study if an AF episode terminates spontaneously or not by analyzing the increase of atrial activity (AA) organization prior to AF termination. The organization varies as a consequence of the decrease in the number of reentries into the atrial tissue. The analysis was carried out noninvasively through the use of surface electrocardiogram (ECG) recordings. Sample entropy (SampEn) was selected as non-linear organization index. It was observed that noise and ventricular residues degrade AA organization estimation performance, therefore the use of selective filtering to get the main atrial wave (MAW) was necessary. Using the MAW organization analysis, that is the signal produced by the fundamental atrial waveform, 46 out of 50 of the terminating and non-terminating analyzed AF episodes were correctly classified (92%). Therefore, this method can provide a clear benefit for patients, doctors and health systems, since it avoids useless therapeutic intervention and minimises the risks for the patients.