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 sin us 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.