Introduction: Mechanisms of atrial fibrillation (Afib) termination still poorly understood. A new method - noninvasive electrocardiographic imaging (ECGI) allows panoramic mapping of Afib in humans. The goal of this study is to investigate the Afib termination processes in patients using ECGI.
Methods: Seven patients (4 male, ages 54±8) with paroxysmal Afib were involved in this study. All patients underwent ECGI procedure (Amycard 01 K System, EP Solutions, SA). In three patients we were able to capture the moment of spontaneous Afib termination in baseline conditions. In four patients we observed Afib termination under intravenous administration of propafenone (dosage 0.5 mg/kg).

Results: In all cases AFIb stopped as results of collision and annihilation of phase singularity points with opposite signs of topological charges (i.e. cores of the rotors with opposite directions of rotations). In 4 cases it occurred by reduction of the unclosed wave fronts (Fig A), in 3 cases by closing of the wave fronts into the rings (fig B).
Conclusions: The observed underlying mechanisms of AFib termination in patients with paroxysmal Afib was the collision and annihilation of the counter- rotated rotors.