In this work we perform a statistical study of organization and synchronization indices in electrogram (EGM) signals obtained during ablation surgery in patients with Atrial Fibrillation (AF). We have considered organization, synchronization and delay indices, obtaining by three different ways, spectral, cross-correlation and wavefront analysis: dominant frequency, f^D, regularity index, I^R, organization index, I^O, coherence, ¿, cross-correlation, ¿ and T , interquartile consistency, C^IQR, normalized consistency measure, CE, and median delay ¿ (computed all in 10-second excerpts). We have studied their temporal and spatial stability, and the correlation between pairs of in-dices. We found that all organization indices are stable measures (C¿V¿ < 0.2) along time and a decrease in the synchronization degree with the increase of distance between electrodes.