Effect of atrial fibrillation organization on internal defibrillation threshold

Aim of the present study is to assess the effect of the organization of atrial fibrillation in the right atrium on the minimum effective cardioversion energy. Thirteen patients were studied, selected a priori for low-energy internal cardioversion (LEIC). LEIC was carried out at increasing energy levels. All patients were monitored by a multipolar basket catheter in basal condition and during cardioversion. Our results showed that the mean organization correlates with the energy of successful cardioversion, and that after each shock no significant differences (Kruskal-Wallis test) were observed in the level of organization. Similar results have been obtained for the differences of organization values, immediately before and after each shock. These results prompt for further studies aimed at measuring electrophysiological properties to predict energy thresholds.