Low Energy Internal Atrial Cardioversion in Atrial Fibrillation Lasting More Than a Year

The aim of this study was to evaluate the efficacy of low energy internal atrial cardioversion in restoring sinus rhythm (SR) in patients with chronic atrial fibrillation (AF) persisting > 1 year. Fifteen patients with chronic AF lasting > 1 year (from 13–48 months, mean 24 ± 13 months) were studied. R wave synchronized 3/3 ms biphasic shocks were delivered between right atrial and coronary sinus (left pulmonary artery in five patients) electrodes. Sedatives or anesthetics were administered only at the patient's request. Results: Stable SR was restored in 14 (93%)of 15 patients after shocks with a mean leading edge voltage of 377 ± 77 V (range 260–500) and a mean delivered energy of 7.3 ± 3.4 J (range 2.6–12.9). The procedure was performed without anesthesia in 6 (40%) patients. All successfully cardioverted patients were treated with flecainide, sotalol, or amiodarone. During a follow up of 7.7 ± 7.9 months (range 1–24) AF recurred in five (36%) patients. Three of five AF recurrences occurred within 3 days after conversion to SR. Conclusion: Internal low energy atrial cardioversion is highly effective in restoring SR even in patients with AF lasting > 1 year. The long-term results from the standpoint of freedom from AF recurrences, are satisfactory, although additional antiarrhythmic treatment is required, particularly in the first days after conversion.