When AFib occurs, the interest to maintain the SR is still required, even if recent studies did not show a significant difference in term of total mortality between rate or rhythm control strategies [AFFIRM, RACE and PIAF studies]. The studies published underlined the anti-arrhythmic drugs limits in patients with both arrhythmias [AFib and AFL]. After years centered on the mechanisms and the electric treatments of AFib, researchers are nowadays focusing on the study's evaluation of the atrial tissue substrate.